EM8500 [EMMICRO]
POWER MANAGEMENT CONTROLLER WITH ENERGY HARVESTING INTERFACE;![EM8500](http://pdffile.icpdf.com/pdf2/p00339/img/icpdf/EM8500_2089386_icpdf.jpg)
型号: | EM8500 |
厂家: | ![]() |
描述: | POWER MANAGEMENT CONTROLLER WITH ENERGY HARVESTING INTERFACE |
文件: | 总34页 (文件大小:1899K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
![](http://public.icpdf.com/style/img/ads.jpg)
EM MICROELECTRONIC - MARIN SA
EM8500
POWER MANAGEMENT CONTROLLER
WITH ENERGY HARVESTING INTERFACE
Features
. Flexible operation with different energy banks
. Primary cell battery
. Secondary cell battery
. Capacitors (gold-cap, super-cap)
. Ultra-low power DCDC boost converter with very high efficiency
. Operating mode minimum voltage VDD_HRV ≥ 100 mV (typical)
. Operating mode minimum power: PIN ≥ 1µW (typical)
. Quiescent current: IQ ≤ 125 nA
. Cold-start minimum voltage: VIN ≥ 300 mV
. Cold-start minimum power: PIN ≥ 3 µW (typical)
. Fast start-up on any energy storage
. Dual energy storage elements
. Power management control
. Multiple independent supply outputs
. Sleep mode and wake-up functions
. User programmable under-voltage and over-voltage levels
. Limited external components
. Device configurations are stored in on-chip E2PROM
. Dynamic configuration through a SPI or I2C interface
. Extended power management status
. Battery on protection mode
. LTS/STS connection status
. Minimum/Maximum voltage warning
Description
The EM8500 is an integrated power management solution for low
power applications. It is specifically designed for efficient operation
with a variety of DC harvesting sources including thermal electric
generators (TEG) or photovoltaic (solar) sources in the μW to mW
range.
The device is designed to speed-up system start-up time when the
main energy storage element (aka Long Term Storage – LTS) is
completely discharged or insufficiently charged to supply the
application, by using a secondary energy storage element (Short
Term Storage - STS).
. USB connected
Applications
. Energy harvesting equipped platforms
. Solar charging
. Thermo-electrical generator harvesting (TEG)
. Wearable systems
. Beacons and wireless sensor networks
. Industrial and environmental monitoring
. Battery operated platforms
When using a non-rechargeable primary battery the EM8500's on-
board PMU offers a mechanism to extend battery life when assisted
by a harvesting element.
The EM8500 incorporates a boost converter able to start with an
input voltage as low as 300 mV and an input power of few μW.
In functional mode the EM8500 operates at energy levels from a DC
harvesting source as low as 100 mV and 1 μW. To maximize
24 Lead MLF
4x4mm body
harvesting efficiency the EM8500 integrates
maximum power point tracking controller.
a programmable
The EM8500 is capable of working with a variety of energy elements
as secondary storage, namely re-chargeable batteries, super-
capacitors or conventional capacitors. In all cases the EM8500
maintains its fast start-up capability that depends only on the
harvester conditions and the STS capacitor value.
24
23
22
21
20
19
1
2
3
4
5
6
18
17
16
15
14
13
VDD_STS
WAKE_UP
VDD_USB
MOSI_SDA
MISO
BAT_LOW
HRV_LOW
VSUP
A USB connection to an external power source is available on the
EM8500 for fast charge of the long term storage element.
EM8500
N.C.
The EM8500 integrates voltage supervisory functions. Minimum and
maximum voltages are controlled on the LTS element to prevent
damage to the energy storage element. Harvester minimum voltage
monitoring allows stopping the DCDC limiting power loss when no
energy can be harvested. Output voltages are kept in a safe range
for the application.
VAUX[2]
VAUX[1]
SCL
7
8
9
10
11
12
To perform granular power management of the application, the
EM8500 integrates four independent supply outputs and a sleep
mode offering the capability to switch off part or all the supplies.
The EM8500 is available in an industry standard QFN24 4x4 package
or as a solder bump flip-chip device.
Figure 1-1 QFN24 Package
1
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
TABLE OF CONTENTS
1. Product description ..................................................................................................................... 4
1.1. Operating modes................................................................................................................................4
1.2. voltage naming conventions ...............................................................................................................4
1.3. Block diagram ....................................................................................................................................5
1.4. Functional description ........................................................................................................................6
1.4.1.
1.4.2.
1.4.3.
Cold-start on harvester ............................................................................................................................................6
Start-up on Long Term Storage (LTS) .......................................................................................................................7
System shut-down ...................................................................................................................................................8
2. Handling Procedures ................................................................................................................... 9
3. Pin description ............................................................................................................................ 9
4. Electrical specifications ............................................................................................................. 10
4.1. Absolute Maximum Ratings..............................................................................................................10
4.2. Operating Conditions........................................................................................................................10
4.3. Electrical Characteristics ...................................................................................................................10
4.4. Timing diagrams...............................................................................................................................12
4.4.1.
4.4.2.
SPI interface ...........................................................................................................................................................12
I2C Interface...........................................................................................................................................................12
5. Product configuration ............................................................................................................... 12
5.1. Status information ...........................................................................................................................12
5.2. Supervising and harvester controller behaviour ................................................................................13
5.2.1.
5.2.2.
5.2.3.
5.2.4.
Storage element.....................................................................................................................................................13
Harvester power supervisory functions.................................................................................................................14
Timing configuration..............................................................................................................................................15
Maximum Power Point tracking.............................................................................................................................16
5.3. Power management functions ..........................................................................................................16
5.4. Primary cell configuration.................................................................................................................18
5.5. Sleep mode and Wake-up functions..................................................................................................19
5.6. Lux-meter ........................................................................................................................................19
5.7. USB charging ....................................................................................................................................21
5.8. Miscellaneous functions ...................................................................................................................21
5.8.1.
5.8.2.
5.8.3.
5.8.4.
Soft reset function .................................................................................................................................................21
Register protection ................................................................................................................................................22
LTS protection DISABLE..........................................................................................................................................22
DCDC off forcing.....................................................................................................................................................22
6. Serial interface.......................................................................................................................... 22
6.1. I2C interface.....................................................................................................................................22
6.2. SPI interface.....................................................................................................................................23
6.2.1.
Interface selection .................................................................................................................................................24
6.3. E2PROM...........................................................................................................................................24
6.3.1.
Accessing the E2PROM ..........................................................................................................................................24
2
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
7. Typical characteristics ............................................................................................................... 27
8. Register map............................................................................................................................. 28
9. Typical Applications .................................................................................................................. 31
9.1. SAMPLE schematics..........................................................................................................................31
9.1.1.
9.1.2.
Solar cell assisted system.......................................................................................................................................31
termo-electrical generator (TEG) assisted system .................................................................................................32
9.2. Inductor selection.............................................................................................................................32
9.2.1.
Reference Inductors...............................................................................................................................................32
9.3. Capacitor selection...........................................................................................................................33
10. Ordering Information.............................................................................................................. 33
11. Package Information .............................................................................................................. 33
11.1.
QFN24 4x4 package .......................................................................................................................33
11.1.1. Package marking ....................................................................................................................................................33
3
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
1.
PRODUCT DESCRIPTION
The EM8500 is a power management IC with battery charger functions. It manages different energy source elements: a harvester through
VDD_HRV, external supply through VDD_USB, a battery or a Long Term Storage (LTS) through VDD_LTS. It generates a local supply on a Short
Term Storage (STS), visible through VDD_STS. The EM8500 provides the supply to the application from the energy sources. Surplus energy is
stored in a LTS element.
Features and benefits include:
Power management controller, extending application battery life: the EM8500 supplies the external application through the pins
VSUP and VAUX[i]. The voltage is delivered directly from VDD_STS or through a regulator. On the VSUP pin a wake-up function allows
to automatically re-enable the supply after a given time. For external devices using an I2C serial interface, it is possible to disconnect
their ground through the use of the auxiliary ground pins (VAUX_GND). This solution avoids supplying the devices connected to a
switched-off output supply through the pull-up of I2C bus. Overall power consumption is reduced by turning off peripheral ICs through
the EM8500.
Battery charger from harvester source: EM8500 manages energy harvesting from a low voltage and low power DC source such as
single/dual junction solar cells or thermal electrical generator (TEG). The device embeds hardware MPPT (Maximum Power Point
Tracking) algorithm to extract maximum energy from the harvester element. The DCDC boost converter is able to start the application
from the harvester source. With its dual storage architecture, application start-up is fast and independent of the battery voltage.
Battery charger from USB source : Fast charging is supported through a USB compatible supply input on the EM8500 (system
start-up and battery charging to maximum voltage with configurable speed).
Voltage and current supervisor: The EM8500 includes supervisory functions to detect harvester energy levels detecting (visible
through the HRV_LOW pin) – and to monitor low battery voltage levels (visible through the BAT_LOW pin).
The EM8500 protects the battery against over voltage conditions and automatically stops charging when a configurable threshold
level is reached.
Configuration with E2PROM, no additional external components: The mode and functional configuration of the EM8500 is
controlled by the host MCU through a SPI or an I2C interface. Voltage supervision thresholds are set by registers. Configuration
parameters are held in on-chip non-volatile memory (E2PROM). The EM8500 default configuration parameter values can be modified
by the user.
1.1. OPERATING MODES
The EM8500 operates in three main modes:
1) Normal mode (STS and LTS Connected)
-
-
-
VLTS is inside battery operating range.
LTS is connected to STS.
The system can be configured to disconnect VAUX or/and VAUX_GND pins.
2) LTS protection mode (STS and LTS disconnected)
-
-
-
-
EM8500 enters this mode when VLTS drops below minimum battery operation (v_bat_min_lo).
BAT_LOW pin is set to '1'.
LTS and STS are disconnected to protect LTS against under voltage condition.
VSUP and VAUX are maintained through the DCDC converter only.
3) Sleep mode
-
-
VSUP is not supplied – no communication on SPI/I2C interface.
VSUP can be re-activated by WAKE_UP pin or internal timer.
1.2. VOLTAGE NAMING CONVENTIONS
To describe the operation of this product, the following set of voltage naming conventions is adopted throughout this document , Table 1-1:
NAME
DESCRIPTION
v_bat_max_hi
Maximum battery voltage. High level of hysteresis.
v_bat_min_hi_dis
v_bat_min_hi_con
v_bat_min_hi
Minimum STS maintenance voltage – acts as v_bat_min_hi when STS and LTS are disconnected
Minimum battery maintenance voltage – acts as v_bat_min_hi when STS and LTS are connected
Minimum battery voltage. High level of hysteresis
Equal to v_bat_min_hi_dis or v_bat_min_hi_con according to the connection state in between STS and LTS.
The term “v_bat_min_hi” is used here whenever there is no specific usage of the connected and disconnected
values
v_bat_min_lo
v_apl_max_hi
v_apl_max_lo
Vcs_hi
Minimum battery voltage. Low level of hysteresis
Maximum application voltage. High level of hysteresis
Maximum application voltage. Low level of hysteresis
Cold start voltage level
v_ulp_ldo
Regulated voltage on VSUP pin
v_hrv_min
Minimum voltage for switching on/off the DCDC. See §5.2.2 for current or voltage detection selection.
Table 1-1 Voltage Naming Conventions
4
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
1.3. BLOCK DIAGRAM
n o i t a c i l p p A
s t s _ s t l _ w s
Figure 1-1 EM8500 Block Diagram
5
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
1.4. FUNCTIONAL DESCRIPTION
The following paragraphs describe the behavior of VSTS, VLTS and VSUP for a series of typical use cases;
(VAUX supplies have the same behavior as VSUP).
1.4.1. COLD-START ON HARVESTER
This use case outlines a start-up on harvester voltage, with all storage elements discharged or in protection mode.
VSTS
VLTS
VSUP
2
1
4
5
4
6
3
v_bat_max_hi
v_bat_max_lo
v_apl_max_hi
v_apl_max_lo
v_ulp_ldo
v_bat_min_hi
v_bat_min_lo
STS
LTS
VSUP
Vcs_hi
t
HRV_LOW
BAT_LOW
Figure 1-2 Start-up and energy storage sequence when LTS is lower than the cold-start voltage
1. The DCDC starts transferring energy from HRV to STS
2. When VSTS is higher than Vcs_hi, the cold start sequences ends, the device boots and the DCDC is switched to main charging mode
with MPPT tracking.
3. When VSTS rises above v_bat_min_hi, VSUP is connected to STS supplying the application
4. When VSTS reaches the maximum application voltage level v_apl_max_lo, the DCDC transfers energy into LTS. The application is
supplied by the CSTS only.
5. When VSTS drops to the minimum pre-defined charge value v_bat_min_hi, the DCDC transfers energy back into STS
6. The system remains in states 4 & 5 until VLTS is higher than the minimum battery voltage required to supply the external application
v_bat_min_hi. Then LTS is connected to STS and both storage elements are charged in parallel. The output BAT_LOW is set to '0'.
6
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
1.4.2. START-UP ON LONG TERM STORAGE (LTS)
This case emulates plugging in a partially charges battery with energy form harvester available. The EM8500 starts on LTS voltage, then
transfer energy form the harvester to the battery.
VSTS
VLTS
VSUP
1
3
2
5
4
5
6
v_bat_max_hi
v_bat_max_lo
v_apl_max_hi
v_apl_max_lo
VSUP
v_ulp_ldo
LTS
v_bat_min_hi
v_bat_min_lo
STS
Vcs_hi
t
HRV_LOW
BAT_LOW
Figure 1-3 Start-up and energy bank sequence when LTS is above the minimum battery level
1. LTS and STS are connected together, VSTS quickly reaches VLTS
.
2. As VSTS reaches Vcs_hi, the system boots and then VSUP is connected to STS (which is also connected to LTS).
3. After VSUP reaches VLTS and VSTS level, the system reaches the same state as the one described in state 6 of §1.4.1
4. When VLTS (and therefore also VSTS) reaches the maximum voltage of the application, VSUP is regulated to v_ulp_ldo.
5. When VLTS and VSTS reach v_bat_max_hi the DCDC stops to protect the battery against over voltage
6. When VLTS and VSTS drop to v_bat_max_lo the DCDC starts again to charge STS and LTS.
7. The system remains in states 5 & 6 to maintain the battery voltage between v_bat_max_hi and v_bat_max_lo.
When a battery charged above the maximum application voltage is connected, the system reacts as above except for VSUP which is regulated
from the start due to the too high VSTS/VLTS level.
7
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
1.4.3. SYSTEM SHUT-DOWN
The EM8500 informs the application when the available energy drops below a minimum level required for operation. After the first warning
(through the VBAT_LOW pad), the device initiates an application shut-down sequence to protect the battery.
The first example scenario shows an application drawing more current than the harvester is able to supply. The application is stopped (phase 3).
Once re-started, it keeps a low current consumption profile allowing the charging of the LTS energy storage.
VSTS
VLTS
VSUP
1
2
3
4
5
6
v_bat_max_hi
v_bat_max_lo
v_apl_max_hi
v_apl_max_lo
v_ulp_ldo
STS
v_bat_min_hi
v_bat_min_lo
LTS
VSUP
Vcs_hi
t
HRV_LOW
BAT_LOW
Figure 1-4 Application shut-down with a working harvester
The second example describes the application shut-down sequence when no energy can be harvested from the harvester cell.
VSTS
VLTS
VSUP
1
2
3
4
v_bat_max_hi
v_bat_max_lo
v_apl_max_hi
v_apl_max_lo
v_ulp_ldo
v_bat_min_hi
v_bat_min_lo
LTS
VSUP
STS
Vcs_hi
t
HRV_LOW
BAT_LOW
Figure 1-5 Application shut-down without energy from the harvester
8
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
2.
HANDLING PROCEDURES
This device has built-in protection against high static voltages or electric fields; however, anti-static precautions must be taken as for any other
CMOS component. Unless otherwise specified, proper operation can only occur when all terminal voltages are kept within the voltage range.
Unused inputs must always be tied to a defined logic voltage level.
3.
PIN DESCRIPTION
PIN
NAME
I/O TYPE
DESCRIPTION
NO.
DIRECTION
SUPPLY
1
2
3
4
5
6
7
8
9
VDD_STS
WAKE_UP
VDD_USB
MOSI_SDA
MISO
SCL
CS
VAUX_GND[2]
VAUX_GND[1]
N.C.
I/O
Input
Input
Input
Output
Input
Input
Output
Output
–
up to 3.6V
–
VSUP
VSUP
VSUP
VSUP
–
Connection for the Short Term energy Storage element (STS)
Wake-up pin
USB power supply connection
SPI MOSI or I2C SDA connection
SPI MISO connection
SPI or I2C clock
SPI chip select and SPI/I2C selection mode(when at ‘1’)
Auxiliary 2 ground connection
Auxiliary 1 ground connection
–
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
VAUX_GND[0]
VAUX[0]
VAUX[1]
VAUX[2]
N.C.
Output
Output
Output
Output
–
–
–
–
Auxiliary 0 ground connection
Auxiliary 0 supply output connection
Auxiliary 1 supply output connection
Auxiliary 2 supply output connection
VSUP
Output
Output
Output
Output
Supply
Supply
Input
–
Main supply output
HRV_LOW
BAT_LOW
VREG
VSS
VSS_DCDC
LX1
VSUP
VSUP
Energy harvester cell low indicator (when at ‘1’)
Battery low indicator (when at ‘1’)
Regulated voltage connection
Device ground connection
Device ground connection
Inductor connection for boost converters
Direct connection from energy harvester
Connection for the Long Term energy Storage element (LTS)
–
–
–
–
–
–
VDD_HRV
VDD_LTS
Input
I/O
Table 3-1 Pin-out description
The digital pads are all supplied by VSUP, with the exception of the WAKE_UP pad whose trigger levels are independent of the supply voltages.
When VSUP is disabled these pads are floating therefore the communication interface is off. All digital pads are active HIGH.
9
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
4.
ELECTRICAL SPECIFICATIONS
4.1. ABSOLUTE MAXIMUM RATINGS
VALUE
UNIT
PARAMETER
MIN
MAX
Power supply VDD_HRV
Power supply VDD_STS, VDD_LTS
Power supply VDD_USB
Input voltage
-0.2
-0.2
-0.2
VSS-0.2
-0.2
2.0
4.6
6.0
VSUP+0.2
3.8
V
V
V
V
V
Input voltage (pin WAKE_UP)
Storage Temperature Range (TSTG
Electrostatic discharge to ANSI/ESDA/JEDEC JS-001-2012 for HBM
)
-65
-2000
150
2000
°C
V
Table 4-1 Absolute maximum ratings
Stresses above these listed maximum ratings may cause permanent damages to the device. Exposure beyond specified operating conditions
may affect device reliability or cause malfunction.
Warning: The device is not functional when exposed to light. When a non-packaged version is used, it is mandatory to protect the device from
light (e.g. glob-top, non-transparent package, metal shield on the PCB …)
4.2. OPERATING CONDITIONS
PARAMETER
SYMBOL
MIN
TYP
MAX
UNIT
(1)
DC input voltage into VDD_HRV
VHRV
VLTS
VSTS
VUSB
CLTS
CSTS
CREG
CHRV
CSUP
CAUX
L1
0.1
0.5
3.0
3.0
5
2
47
1.8
4.2
4.2
5.5
V
V
V
V
F
µF
nF
µF
µF
µF
µH
Long Term energy Storage bank voltage
Short Term energy Storage bank voltage
VDD_USB voltage
Long term capacitor(2)
Short term capacitor
0.001
10
470
4.7
1
Regulated voltage capacitor
Harvester capacitor (nominal value)
VSUP capacitor
10
0.1*CSTS
0.1*CSTS
56.4
VAUX capacitor
Input inductance
1
37.6
47
(1) Cold-start has been completed
(2) When using a super-capacitor
Table 4-2 Operating Conditions
4.3. ELECTRICAL CHARACTERISTICS
Unless otherwise specified: TA=-40 to +85°C for min max specifications and TA= 25°C for typical specifications.
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNIT
End of cold-start Voltage on VDD_STS
Start of cold-start Voltage on VDD_STS
Typical DC input voltage range into VDD_HRV
Typical input power range
Minimum cold-start voltage for charging STS
Minimum cold-start input power
Vcs_hi
Vcs_lo
With VSTS increasing
With VSTS decreasing
Cold-start completed
VSTS > Vcs_hi VVDD_HRV = 0.5V
VSTS < Vcs_lo
1.3
1.1
V
V
V
mW
mV
µW
s
0.1
0.001
1.8
100
1800
300
3
2
VSTS < Vcs_lo
Cold-start duration
CSTS = 47uF, VHRV = 0.5V, PHRV = 100µW, VSTS(0s)=0V,
VLTS(0s)=0V, v_bat_min_hi=2V
CURRENT CONSUMPTIONS ON LTS
IDD in “LTS protection mode” and “HRV low
mode”
ILTS_prot1
Battery supervisory at 4Hz; VSUP and VAUX LDOs disabled
65
nA
IDD in “LTS protection mode”
IDD in “HRV low mode” STS and LTS connected
IDD in “HRV low mode” STS and LTS connected
ILTS_prot2
IHRV_lo2
IHRV_lo3
Battery supervisory at 4Hz; VSUP and VAUX LDOs disabled
Battery supervisory at 4Hz; VSUP and VAUX LDOs disabled
Battery supervisory at 4Hz; ULP LDO enabled and VAUX LDO
disabled
15
145
170
nA
nA
nA
IDD in “HRV low mode” STS and LTS connected
IDD in “HRV low mode” STS and LTS connected
IDD in “HRV low mode” STS and LTS connected
IDD in “HRV low mode” STS and LTS connected
IDD in “normal mode” STS and LTS
IHRV_lo4
IHRV_lo5
IHRV_lo6
IHRV_lo6
INORM
Battery supervisory at 4Hz; VSUP and VAUX[0] LDO enabled
Battery supervisory at 4Hz; VSUP and VAUX[1] LDO enabled
Battery supervisory at 4Hz; VSUP and VAUX[2] LDO enabled
Battery supervisory at 4Hz; VSUP and all VAUX LDO enabled
Battery supervisory at 4Hz; VSUP and VAUX LDOs disabled
(VDD_STS < VDD_LTS)
285
265
250
380
45
nA
nA
nA
nA
nA
disconnected
QUIESCENT CURRENT AND LEAKAGE ON STS (WHEN LTS IS NOT CONNECTED TO STS)
IDD in “HRV low mode”
ISTS_hrvlo
Battery supervisory at 4Hz; VSUP and VAUX LDOs disabled
65
nA
VSUP AND VAUX LDO VOLTAGE LEVEL
ULP/VAUX LDO level 0
ULP/VAUX LDO level 1
ULP/VAUX LDO level 2
ULP/VAUX LDO level 3
ULP/VAUX LDO level 4
ULP/VAUX LDO level 5
ULP/VAUX LDO level 6
ULP/VAUX LDO level 7
VSTS – VSUP> 0.3V
VSTS – VSUP> 0.3V
VSTS – VSUP> 0.3V
VSTS – VSUP> 0.3V
VSTS – VSUP> 0.3V
VSTS – VSUP> 0.3V
VSTS – VSUP> 0.3V
VSTS – VSUP> 0.3V
1.08
1.39
1.48
1.62
1.8
1.98
2.16
2.34
1.2
1.55
1.65
1.8
2
2.2
2.4
2.6
1.32
1.71
1.82
1.98
2.2
2.42
2.64
2.86
V
V
V
V
V
V
V
V
MAXIMUM CURRENT ON THE ULP AND VAUX LDO
Maximum current on ULP LDO
Maximum current on VAUX[0] LDO
Maximum current on VAUX[1] LDO
Maximum current on VAUX[2] LDO
Drop from open voltage is 100 mV, LDO level at 1.8V
Drop from open voltage is 100 mV, LDO level at 1.8V
Drop from open voltage is 100 mV, LDO level at 1.8V
Drop from open voltage is 100 mV, LDO level at 1.8V
10
20
10
5
mA
mA
mA
mA
SWITCH RESISTOR
VDD_LTS to VDD_STS
VDD_STS to VSUP
VDD_STS to VAUX[0]
VDD_STS to VAUX[1]
Rsw_LTS_STS
Rsw_VSUP
Rsw_VAUX0
Rsw_VAUX1
VDD_STS at 3V
VDD_STS at 3V
VDD_STS at 3V
VDD_STS at 3V
3.1
7.4
4.4
5.8
Ω
Ω
Ω
Ω
10
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
PARAMETER
SYMBOL
Rsw_VAUX2
Rsw_GND0
CONDITIONS
MIN
TYP
6.4
4.74
5.62
MAX
UNIT
VDD_STS to VAUX[2]
VDD_STS at 3V
VDD_STS at 3V
VDD_STS at 3V
Ω
Ω
Ω
VAUX_GND[0] to VSS
VAUX_GND[1,2] to VSS
Rsw_GND1,2
SUPERVISORY LEVELS ON STS, LTS AND HRV(1)
Maximum voltage
4.2
V
Level step from lvl0 to lvl15
Vlvl_15
Vlvl_30
Vlvl_54
73
73
73
±0.5
54
mV
mV
mV
LSB
Level step from lvl16 to lvl30 (1.24V to 2.26V)
Level step from lvl31 to lvl54 (2.34V to 4.2V)
Differential non linearity
67.9
69.4
78.1
76.7
Number of levels
HARVESTER CURRENT LEVEL DETECTOR – LUX METER
Harvester current level step
Luxmeter current detection level
“lvl” = level used for the measurement [0..15]
Short circuit voltage
Ihrv_check_lvl
Ilux_lvl
1
µA
µA
2lvl
Vhrv_scv
70
mV
USB POWER
Minimum voltage for USB charging detection
Regulated voltage on VDD_STS
Current source level 0 on LTS
Current source level 1 on LTS
Current source level 2 on LTS
Current source level 3 on LTS
E2PROM PARAMETERS
E2PROM write time
Vusb_min
VUSB_REG
IUSB_lvl0
IUSB_lvl1
IUSB_lvl2
IUSB_lvl3
3.5
2.1
0
6.9
12.7
20.6
V
V
mA
mA
mA
mA
Tee_wr
Tee_rd
Nee_cyc
Thd_rd
8
0.9
ms
ms
E2PROM read time
E2PROM maximum write cycle
E2PROM read hold time
INTERFACE PARAMETERS
Input WAKE_UP - low level
Input WAKE_UP - high level
Wake-up rising edge reaction time
Wake-up falling edge reaction time
Input - low level
1000
0.9
10
µs
Vil_wk
Vih_wk
Tr_wk
Tf_wk
Vil_si
VLTS=1.2V to 3.6V
VLTS =1.2V to 3.6V
Debouncer disabled
Debouncer disabled
VSUP=1.2V to 3.6V
0.3
V
V
µs
µs
V
4.5
120
0.2*
VSUP
Input - high level
Vih_si
VSUP =1.2V to 3.6V
0.8*
VSUP
3
3
1
V
Output – low level for I2C(3)
Output – low level for I2C
Output – low level(3)
Iol_sda
Iol_sda_1.2
Iol
VSUP =1.8V, Vol=0.2* VSUP
VSUP =1.20V, Vol=0.23*Vsup
VSUP =1.8V, Vol=0.2*Vsup
mA
mA
mA
(MISO, MOSI_SDA, BAT_LOW, HRV_LOW)
VSUP =1.20V, Vol=0.23*Vsup
(MISO, MOSI_SDA, BAT_LOW, HRV_LOW)
VSUP =1.8V, Voh=0.8*Vsup
(MISO, MOSI_SDA, BAT_LOW, HRV_LOW)
VSUP =1.2V, Voh=0.8*Vsup
(MISO, MOSI_SDA, BAT_LOW, HRV_LOW)
On MOSI_SDA and SCL
Output – low level
Output – high level(3)
Output – high level
Iol_1.2
Ioh
Ioh_1.2
Cb
1
mA
mA
mA
pF
-1
-1
I2C bus load capacitor
SPI TIMINGS
400
SPI clock input frequency
SCL low pulse
SCL high pulse
MOSI_SDA setup time
MOSI_SDA hold time
MISO output delay
MISO output delay
CS setup time
Fspi
Tlow_scl
Thigh_scl
Tsetup_mosi
Thold_mosi
Tdelay_miso
Tdelay_miso
Tsetup_cs
Thold_cs
5
MHz
ns
ns
ns
ns
ns
ns
ns
ns
20
20
20
20
25pF load, VSUP =1.6V min
25pF load, VSUP =1.2V min
30
40
50
20
CS hold time
I2C TIMINGS(2)
MOSI_SDA setup time
tsudat
thddat
Standard & Fast Modes
High Speed Mode
160
30
80
90
18
ns
ns
ns
ns
ns
ns
ns
MOSI_SDA hold time
Standard & Fast Modes with Cb =100pF Max.
Standard & Fast Modes with Cb =400pF Max
High Speed Mode with Cb=100pF Max.
High Speed Mode with Cb=400pF Max.
High Speed Mode with Cb=100pF Max.
VSUP =1.8V
115
150
24
160
SCL low pulse(3)
SCL low pulse
tlow
tlow
High Speed Mode with Cb=100pF Max. VSUP =1.2V
210
ns
(1) The v_bat_min, v_bat_max, v_apl_min with their hysteresis can be set according to the supervising levels. E.g. for v_bat_max, both v_bat_max_lo and
v_bat_max_hi will have to be set accordingly.
(2) Refers to I2C specification 2.1 (January 2000)
(3) When reg_ext_cfg.sdi_slope_ctrl = ‘1’
Table 4-3 Electrical Specifications
11
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
4.4. TIMING DIAGRAMS
4.4.1. SPI INTERFACE
CS
Thold_cs
Tsetup_cs
SCL
Tlow_scl
Thigh_scl
MOSI_SDA
MISO
Tsetup_mosi
Thold_mosi
Tdelay_miso
Figure 4-1 4-wire SPI Timing Diagram
4.4.2. I2C INTERFACE
MOSI_SDA
tbuf
tf
tlow
SCL
thigh
thdsta
tr
thddat
tsudat
MOSI_SDA
tsusta
tsusto
Figure 4-2 I2C Timing Diagram
5.
PRODUCT CONFIGURATION
The EM8500 is an autonomous power management system able to manage power domains, power sources and storage elements.
At start-up the device enters a boot sequence. It controls the state of both energy storage elements, and sets the default configuration parameters
of the device by retrieving the corresponding values from the on-chip E2PROM.
Upon completion of the boot sequence the system enters the supervising and harvester controller state (“normal mode”). It is now possible to
modify configuration parameters through the serial interface to change the behavior of the device. When updating the device configuration through
the serial interface it is recommended to write the complete set of EM8500 configuration parameters in a single transaction (see §6).
EM8500 is able to operate autonomously by using default configuration values from the on-chip E2PROM.
5.1. STATUS INFORMATION
EM8500 provides status feed-back as follows.
To allow fast system response the pins HRV_LOW and BAT_LOW directly indicate the status of the harvester cell and the battery to
the host MCU.
Additional status information is provided through register reg_status. During an SPI transaction the reg_status value sent as the first
byte (along with the indication from the MCU of the address to be accessed). In case of an I2C transaction the reg_status register has
to be polled explicitly.
12
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
Register Name: reg_status
Bit name
Address: 0x22
Description
Bits
Type Reset
'1' EEPROM being written. Wait for new configuration
'0' EEPROM ready to be written. New configuration can be written
7
eeprom_data_busy
RO
RO
RO
0
0
0
'1' lux-meter or HRV current supervisory is running
‘0’ no current measurement on the harvester on-going.
6
5
hrv_lux_busy
hrv_low
'1' HRV energy level too low for harvesting
'0' HRV has enough energy to be harvested
'1' LTS voltage lower than v_bat_min_hi in normal mode, lower than
v_bat_min_lo in primary cell mode
‘0’ LTS voltage higher than v_bat_min_hi in normal mode, higher than
v_bat_min_lo in primary cell mode
4
bat_low
RO
0
'1' DCDC is charging LTS
‘0’ DCDC is charging STS
3
2
1
0
sw_vdcdc_lts_nsts
sw_lts_sts
RO
RO
RO
RO
0
0
0
0
'1' LTS and STS are connected
‘0’ STS is disconnected from LTS
'1' USB power has been detected
‘0’ No USB power found
usb_on
'1' LTS protection mode activated (VLTS < v_bat_min_lo)
‘0’ LTS protection mode inactive (VLTS > v_bat_min_lo)
lts_protect
Table 5-1 Status Register (0x22)
EM8500 offers great flexibility in being configured for different system applications and use cases. The following chapters provide detailed
descriptions of all configuration parameters and registers available to the user.
5.2. SUPERVISING AND HARVESTER CONTROLLER BEHAVIOUR
5.2.1. STORAGE ELEMENT
Storage element voltage and state are available through the reg_vld_status register.
Reguster name: reg_vld_status
Bit name Type Reset
Address: 0x23
Description
Bits
'1' VLTS > v_bat_min_hi
'0' VLTS <= v_bat_min_hi
7
lts_bat_min_hi
RO
RO
RO
RO
RO
RO
RO
RO
0
0
0
0
0
0
0
0
'1' VLTS > v_bat_min_lo
'0' VLTS <= v_bat_min_lo
6
5
4
3
2
1
0
lts_bat_min_lo
sts_bat_max_hi
sts_bat_max_lo
sts_apl_max_hi
sts_apl_max_lo
sts_bat_min_hi
sts_bat_min_lo
'1' VSTS > v_bat_max_hi
'0' VSTS <= v_bat_max_hi
'1' VSTS > v_bat_max_lo
'0' VSTS <= v_bat_max_lo
'1' VSTS > v_apl_max_hi
'0' VSTS <= v_apl_max_hi
'1' VSTS > v_apl_max_lo
'0' VSTS <= v_apl_max_lo
'1' VSTS > v_bat_min_hi
'0' VSTS <= v_bat_min_hi
'1' VSTS > v_bat_min_lo
'0' VSTS <= v_bat_min_lo
Table 5-2 Voltage Status Register (0x23)
13
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
Operation of the two energy banks (LTS and STS) is performed through three key voltage threshold levels.
Minimum battery level voltage
Maximum battery level voltage
Maximum application level voltage
v_bat_min (reg_v_bat_min_hi_con or reg_v_bat_min_hi_dis and reg_v_bat_min_lo)
v_bat_max (reg_v_bat_max_hi and reg_v_bat_max_lo)
v_apl_max (reg_ v_apl_max_hi and reg_v_apl_max_lo)
The three levels include a hysteresis to avoid instability of the controller. The hysteresis values have to be carefully chosen according to the
application and have to fulfill the following conditions:
v_bat_min_hi_dis > v_bat_min_hi_con > v_bat_min_lo
v_apl_max_hi > v_apl_max_lo
v_bat_max_hi > v_bat_max_lo
If v_apl_max ≥ v_bat_max the application maximum level is considered to be the maximum battery level.
Supervising of the minimum battery level is performed through two registers for its highest control level (v_bat_min_hi). When the two battery
banks are not connected v_bat_min_hi_dis is used to inform the system when it has to charge STS again (see phase 4 to 5 in Figure 1-2 on
page 6). When LTS and STS are connected together v_bat_min_hi_con is used as supervising level.
The minimum value allowed for the v_bat_min_hi_dis register is 0x15 corresponding to typically 1.47 V. For any value lower than this minimum
the system may shut-down without notification through the BAT_LOW pin.
All voltage levels with prefix “v_” are configured by register according to the following equation:
v_<voltage name> = Vlvl * (reg_<voltage name>+1)
Supervisory status of the battery is also visible through the pin BAT_LOW. When the VLTS is below v_bat_min_hi for two consecutive
measurements, BAT_LOW is asserted (set to VSUP level). When two measurements show that VLTS is above v_bat_min_hi, BAT_LOW is de-
asserted (set to VSS). The only exception is during the boot phase where the BAT_LOW signal is asserted after the first measurement of VLTS
.
The EM8500 protects the battery when its voltage is too low. This corresponding threshold level can be set through the v_bat_min_lo register.
When VLTS is falling below this value the EM8500 operates only on the harvester.
5.2.2. HARVESTER POWER SUPERVISORY FUNCTIONS
The EM8500 monitors harvester power to disable DCDC operation when no energy is available.
Two mechanisms for harvester monitoring are available (selectable trough reg_v_hrv_min.hrv_check_vld) through the same Voltage
Level Detector used for the supervision of LTS and STS or through a specific dedicated engine.
Voltage detection (used for TEG harvester type): the threshold level of supervision can be set on the reg_v_hrv_cfg.v_hrv_min
register. There is no hysteresis on this threshold.
Current detection (used for solar harvester type): The device is sensing the current at the voltage Vhrv_scv delivered by the harvester.
The current threshold of detection is set through the reg_hrv_check_lvl.hrv_check_lvl register to transition from running state to DCDC
disable. To return to the running state, the EM8500 detection is done with a different principle. The current measurement is done by
connecting a resistance on VDD_HRV and sense voltage on this pin using v_hrv_min voltage level.
Resistances and currents are defined in reg_hrv_check_lvl.hrv_check_lvl:
reg_hrv_check_lvl.hrv_check_lvl 0x00 0x01 0x02 0x03 0x04 0x05 0x06 0x07 0x08 0x09 0x0A 0x0B 0x0C 0x0D 0x0E 0x0F
Current (µA)
1
2
3
4
5
6
7
8
9
7
10
11
12
13
5
14
15
16
Resistance (kΩ)
35 23.3 17.5 14 11.7 10 8.75 7.8
6.36 5.38 5.4
4.7
4.4
4.4
Table 5-3 HRV Current Detection Levels
Configuration example:
reg_hrv_check_lvl =0x00; reg_v_hrv_cfg = 0x00
The system indicates HRV_LOW =’1’ from 1µA at Vhrv_scv (70mV) and remains off until Vlvl is reached with 35 kΩ load on VDD_HRV
(2 µA at Vlvl). A hysteresis of 1 µA is applied.
Register name: reg_v_hrv_cfg
Address: 0x04
Default value mapped in E2PROM
Description
Bits
Bit name
Type
7
–
–
Reserved
'1' indicates that the HRV is checked by the voltage supervisory
'0' indicates that the HRV is checked by the current supervisory
6
hrv_check_vld
v_hrv_min
RW
RW
Minimum HRV open voltage required to generate energy.
Vhrv_min = Vlvl * (reg_v_hrv_min(5:0)+1)
5:0
if VHRV < Vhrv_min and reg_v_hrv_cfg.hrv_check_vld = '1' then reg_status.hrv_low = '1'
Table 5-4 Minimum HRV voltage (0x04)
14
www.emmicroelectronic.com
420005-A01, 2.0
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
EM8500
Register name: reg_hrv_check_lvl
Address: 0x05
Default value mapped in E2PROM
Description
Bits
Bit name
Type
7:4
–
–
Reserved
Minimum HRV short-cut current level to generate energy.
Ihrv_check = (hrv_check_lvl+1) * 1µA
3:0
hrv_check_lvl
RW
if IHRV < Ihrv_check and reg_v_hrv_cfg.hrv_check_vld = '0' then reg_status.hrv_low = '1'
Table 5-5 Minimum HRV short-cut current (0x05)
When LTS and STS are not connected internally (in “primary cell mode” or in “battery protection mode”) the DCDC booster is able to deliver up to
around 1mW maximum to the application. This value depends on input (VDD_HRV) and output (VDD_STS) voltages.
5.2.3. TIMING CONFIGURATION
In addition to voltage level supervision, the user can select independent values for the frequency of supervision on LTS, STS and the harvester.
The frequency influences the overall EM8500 power consumption and therefore its efficiency.
The STS and LTS measurement periods are set through the registers reg_t_sts_period and reg_t_lts_period. The monitoring of the harvester
however requires stopping the DCDC pumping process for a short time to measure the open voltage (in case the VLD is used) or the short-cut
current (in case the current level detector is used). The duration of the DCDC disable period is configured through the reg_t_hrv_meas register,
whereas the measurement period is configured through the reg_t_hrv_period register.
VDD_HRV
Harvester open voltage
Regulation running
sampling
MPPT target voltage
eas
t_hrv_m
t_hrv_period
t
Figure 5-1 DCDC Regulation Timings
Register value
t_hrv_meas
t_hrv_period
t_sts_period
t_lts_period
t_hrv_low_period
t_lts_hrv_low_period
0x00
0x01
16 ms
32 ms
256 ms
512 ms
1 ms
2 ms
1 ms
4 ms
256 ms
512 ms
2 ms
8 ms
32 ms
128 ms
512 ms
2 s
0x02
0x03
0x04
0x05
0x06
0x07
64 ms
128 ms
256 ms
512 ms
1 s
1 s
2 s
8 ms
16 ms
32 ms
64 ms
128 ms
256 ms
16 ms
64 ms
256 ms
1 s
1 s
2 s
4 s
4 s
8 s
8 s
16 s
32 s
4 s
16 s
32 s
8 s
2 s
16 s
32 s
Table 5-6 Timing Configuration
When entering in “HRV low mode” the monitoring on LTS and the harvester remains active, however the monitoring frequency can be adapted to
this situation where the system cannot take energy anymore from the harvester source. The measurement period is then set in parameter
t_hrv_low_period. In this mode STS is not fed by the harvester anymore. If STS and LTS are not connected internally, STS will collapse. No
monitoring is performed on STS.
When the harvester is monitored (reg_v_hrv_cfg.hrv_check_vld) based on the voltage measurement, the sampling value is set at the same
frequency as the harvester voltage check. However, if the current level detector is used, the measurement of the current is done alternatively with
the MPPT target setting, dividing by 2 the effective frequency of measurement and setting. For example if Thrv_period is set to 4 s, the period for
checking the harvester voltage is 8 s, as well as the one for the MPPT target setting, and the harvester current checking is done 4 s after the
MPPT target setting.
15
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
5.2.4. MAXIMUM POWER POINT TRACKING
To efficiently cope with different DC sources EM8500 offers a configurable MPPT controller. The MPPT target ratio for the DCDC boost converter
can be set between 50% (suitable for TEG sources) and 88% (80% being a standard value for solar cells). The ratio is programmed in register
reg_mppt_ratio.
Register name: reg_mppt_ratio
Address: 0x12
Default value mapped in E2PROM
Bits
Bit name
Type
Description
7:4
–
–
Reserved
mppt_ratio
RW MPPT ratio for the DCDC power point tracking
"0000"
"0001"
"0010"
"0011"
"0100"
"0101"
"0110"
"0111"
"1000"
"1001"
"1010"
"1011"
"11--"
(0x0)
(0x1)
(0x2)
(0x3)
(0x4)
(0x5)
(0x6)
(0x7)
(0x8)
50%
60%
67%
71%
75%
78%
80%
82%
83%
85%
86%
87%
88%
3:0
(0x9)
(0xA)
(0xB)
(0xC to 0xF)
Table 5-7 MPPT Ratio Selection Register (0x12)
5.3. POWER MANAGEMENT FUNCTIONS
The EM8500 controls four independent power supply outputs.
The VSUP power supply output is connected to STS when STS level is within the application voltage range ([v_bat_min:v_apl_max]) or to an
LDO (when above v_apl_max) to regulate the output to a given value.
The three auxiliary supply outputs VAUX [0:2], are user configurable between STS and the internal LDO. It is possible to force the use of the LDO
even though the STS voltage level is compatible with the application supply requirements.
During the boot phase – which corresponds to the set-up of the device – all the power supply outputs are floating. Once the set-up of the registers
is completed the supply output values are determined by configuration registers reg_ldo_cfg.vsup_tied_low and reg_vaux_cfg.vaux[x]_cfg.
The main application power supply (VSUP) is intended to be connected to the application controller. When connected to the LDO its maximum
power is limited as LDO is optimized for low consumption. The VSUP supply output is controlled by the reg_ldo_cfg register.
The value of the LDO is configurable through reg_ldo_cfg.v_ulp_ldo. The LDO enable can be forced with reg_ldo_cfg.frc_ulp_ldo. In “sleep state”,
VSUP can be grounded (reg_ldo_cfg.vsup_tied_low = ‘1’) or floating (reg_ldo_cfg.vsup_tied_low = ‘1’) (see §5.4).
The individual configurability of the three auxiliary supply outputs allows the creation of different power domains for the external application. The
auxiliary outputs are split into the supply and ground pins where all six outputs can be switched on/off independently.
The behavior of the VAUX pins is controlled through the reg_vaux_cfg register. reg_vaux_cfg.v_aux_ldo controls the level of the single LDO
connected to the three auxiliary supplies.
When switched on (reg_pwr_mgt.vaux[i]_en = ‘1’) the auxiliary supply output is controlled by reg_vaux_cfg.vaux[i]_cfg.
Four possible settings are available to the user:
1) Force the connection to STS
2) Force the connection to the LDO
3) Use the automatic configuration permitting the auxiliary output to float when STS drops below v_bat_min
4) Use the automatic configuration grounding the auxiliary output when STS drops below v_bat_min
The automatic configuration of the auxiliary supplies is ensures that the auxiliary output voltage is kept within the application voltage range by
auto-connecting the supply output to the LDO when STS voltage is exceeding the v_apl_max value.
When the power supply output is switched off (reg_pwr_mgt.vaux[i]_en = ‘0’), its configuration is also controlled by the reg_pwr_mgt.vaux[i]_cfg
register. The output is grounded if reg_pwr_mgt.vaux[i]_cfg is set to 3 (b11), otherwise it is kept floating.
When the LDO is used on VSUP or VAUX pins, changing the LDO settings does not generate over or under shoots on the output power supply
terminals.
EM8500 offers the possibility to control the ground pin as part of the application, by connecting it to the ground of the EM8500 or letting it float. It
is of particular interest when involving applications that are using I2C communication through the pulls of the I2C lines. The configuration of the
VAUX_GND pins is controlled through the reg_pwr_mgt.vaux_gnd[i] en register.
16
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
Register name: reg_ldo_cfg
Bit name
Address: 0x0E
Default value mapped in E2PROM
Description
Bits
Type
RW When set to '1', connects VSUP pin to ground when VSUP is disabled, otherwise VSUP
remains floating.
7
vsup_tied_low
RW VAUX LDO regulated voltage selection
"000" (0)
"001" (1)
"010" (2)
"011" (3)
"100" (4)
"101" (5)
"110" (6)
"111" (7)
1.2 V
1.55 V
1.65 V
1.8 V
2.0 V
2.2 V
2.4 V
2.6 V
6:4
v_vaux_ldo
frc_ulp_ldo
v_ulp_ldo
3
RW Force ULP LDO on as soon as VSTS > v_bat_min_hi
RW ULP LDO regulated voltage selection
"000" (0)
"001" (1)
"010" (2)
"011" (3)
"100" (4)
"101" (5)
"110" (6)
"111" (7)
1.2 V
1.55 V
1.65 V
1.8 V
2.0 V
2.2 V
2.4 V
2.6 V
2:0
Table 5-8 VSUP output supply and LDOs configuration register (0x0E)
Register name: reg_pwr_cfg
Bit name
Address: 0x0F
Default value mapped in E2PROM
Description
Bits
Type
'1' Disable USB LDO after boot sequence even if usb_crt_src_sel is > 0x0
‘0’ Keep the default behavior on USB LDO
7
usb_ldo_frc_dis
RW
'1' open the VAUX_GND[2] (pin is floating) in "HRV low" mode.
'0' Keep the same behavior as in normal mode
6
dis_vaux_gnd2_hrv_low
RW
5
4
dis_vaux_gnd1_hrv_low
dis_vaux_gnd0_hrv_low
RW "HRV low" mode VAUX_GND[1] behavior. same as for pin VAUX_GND[2]
RW "HRV low" mode VAUX_GND[0] behavior. same as for pin VAUX_GND[2]
'1' Disable vaux[2] in "HRV low" mode. It is configured by reg_vaux_cfg.vaux2_cfg
'0' Keeps its normal mode configuration.
3
dis_vaux2_hrv_low
RW
2
1
dis_vaux1_hrv_low
dis_vaux0_hrv_low
RW "HRV low" mode VAUX[1] behavior. same as for pin VAUX[2]
RW "HRV low" mode VAUX[0] behavior. same as for pin VAUX[2]
'1' Disable VSUP in "HRV low" mode. Its behavior is defined by
reg_ldo_cfg.vsup_tied_low
0
dis_vsup_hrv_low
RW
'0' Keeps its normal mode configuration
Table 5-9 "HRV low" mode power switch configuration register (0x0F)
Register name: reg_vaux_cfg
Address: 0x10
Default value mapped in E2PROM
Description
Bits
Bit name
Type
7:6
–
–
Reserved
vaux2_cfg
RW Configuration of VAUX[2] pin
"00" (0) Constantly connected to STS
"01" (1) Constantly connected to the LDO
"10" (2) Automatic configuration – floating when below VSTS < v_bat_min
"11" (3) Automatic configuration – grounded when below VSTS < v_bat_min
5:4
If VAUX[2] is disconnected – VAUX[2] is connected to ground if the value is "11", otherwise
it is floating
3:2
1:0
vaux1_cfg
vaux0_cfg
RW Configuration of VAUX[1] pin – same as for VAUX[2] pin
RW Configuration of VAUX[0] pin – same as for VAUX[2] pin
Table 5-10 Auxiliary supply configuration register (0x10)
17
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
Register name: reg_vaux_gnd_cfg
Address: 0x11
Default value mapped in E2PROM
Description
Bits
7:3
2
Bit name
Type
–
–
Reserved
vaux_gnd2_cfg
RW
'1' Auto disconnect when VSTS not within [v_bat_min.. v_apl_max]
'0' Fully manual connection
1
0
vaux_gnd1_cfg
vaux_gnd0_cfg
RW Configuration of VAUX_GND[1] pin – same as for VAUX_GND [2] pin
RW Configuration of VAUX_GND[0] pin – same as for VAUX_GND[2] pin
Table 5-11 Auxiliary ground pins configuration register (0x11)
Register name: reg_pwr_mgt
Bit name
Address: 0x19
Value at start-up mapped in E2PROM
Description
Bits
Type
7
frc_prim_dcdc_dis
RW
'1' Force the DCDC off
'0' Keep the automatic mode of the DCDC
6
5
4
vaux_gnd2_en
vaux_gnd1_en
vaux_gnd0_en
RW Enable the VAUX_GND[2] connection (see reg_vaux_gnd_cfg.vaux_gnd2_cfg) when VSTS
>
>
>
v_bat_min_hi
RW Enable the VAUX_GND[1] connection (see reg_vaux_gnd_cfg.vaux_gnd0_cfg) when VSTS
v_bat_min_hi
RW Enable the VAUX_GND[0] connection (see reg_vaux_gnd_cfg.vaux_gnd0_cfg) when VSTS
v_bat_min_hi
3
2
1
0
vaux2_en
vaux1_en
vaux0_en
sleep_vsup
RW Enable the VAUX[2] connection (see reg_vauxcfg.vaux2_cfg) when VSTS > v_bat_min_hi
RW Enable the VAUX[1] connection (see reg_vauxcfg.vaux1_cfg) when VSTS > v_bat_min_hi
RW Enable the VAUX[0] connection (see reg_vauxcfg.vaux0_cfg) when VSTS > v_bat_min_hi
RW Enable the VSUP "sleep state" – disconnects VSUP for t_sleep_vsup interval
Table 5-12 Power switch enable register (0x19)
5.4. PRIMARY CELL CONFIGURATION
The EM8500 supports supplying an application through a combination of a primary cell and a harvesting element by setting reg_lts_cfg.prim_cell
to ‘1’.
In this case the application is mainly supplied by STS. LTS is automatically connected to STS as soon as the harvesting element is not providing
enough energy to supply the application. LTS is disconnected from STS as soon as the harvester provides enough energy to the system again.
LTS and STS are connected automatically when HRV_LOW is asserted, or if after a measurement of VSTS below v_bat_min_hi_dis, a successive
measurement (1 ms later) on STS confirms that the level is still below v_bat_min_hi_dis. The connection remains for two periods of HRV
measurements.
If the battery level is below v_bat_min_lo STS and LTS are kept disconnected to avoid damaging the battery cell.
The checks on the harvester and STS are done with the same frequencies as shown in §5.2.1.
It is possible to force the connection between STS and LTS, preventing the use of the DCDC converter to harvest energy from the harvester cell
– reg_lts_cfg.prim_cell_connect = ‘1’. This is particularly useful to perform high energy tasks.
When the device is in LTS protect mode (reg.status.lts_protect = ‘1’) forcing the primary cell connection has no effect. The system continues to
be supplied by the harvester. Forcing a connection leads to the collapse of the supply as the battery is too low.
By permanently connecting STS and LTS it is also possible to use only a primary cell (without harvester) and taking advantage of the EM8500
power management features to control the 4 power supply domains and their automated nodes.
Register name: reg_lts_cfg
Address: 0x06
Default value mapped in E2PROM
Description
Bits
7:3
2
Bit name
–
Type
–
Reserved
prim_cell_connect
RW
'1' Connect LTS and STS if reg_lts_cfg.prim_cell = ‘1’.
‘0’ Normal mode on STS
1
0
prim_cell
RW
RW
'1' Sets the device in primary cell mode. The DCDC never charges LTS
‘0’ Sets the device in secondary cell mode (LTS is rechargeable)
no_bat_protect
'1' Disables the battery protection feature. (reg.status.lts_protect = ‘0’)
‘0’ Enables the battery protection feature.
Table 5-13 LTS configuration register (0x06)
18
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
When the primary cell mode is selected the lux-meter function can only be used when both LTS and STS are forced to be connected together –
reg_lts_cfg.prim_cell_connect = ‘1’.
5.5. SLEEP MODE AND WAKE-UP FUNCTIONS
In addition to the direct control of the power supply outputs the EM8500 supports stopping supplying the application (switching off VSUP) for a
given time interval to allow very low consumption modes. When enabled, the auxiliary supplies are kept in the same state as before entering in
the “sleep state”. The “sleep state” is not a functional mode of the power management unit, as the device is still working according to the
configuration parameters set and is only acting on the state of the VSUP supply output.
The “sleep state” can also be interrupted (VSUP is connected again on STS or on the LDO according to the settings of the VSUP power switch
see Table 5-8) by setting the WAKE_UP pin to a level above Vih_wk
.
During “sleep state” the serial interface is disabled.
To avoid false wake-up detection, a debouncing logic is connected to the WAKE_UP pin. The debouncer function is enabled by default (factory
default value on E2PROM), and can be disabled by setting the reg_ext_cfg. wake_up_deb_en to ‘0’. The wake-up is sensitive to the edge
configured in reg_ext_cfg.wake_up_edge_cfg. It is not permitted to set reg_ext_cfg.wake_up_edge_cfg = “00”.
Register name: reg_ext_cfg
Bit name
Address: 0x13
Default value mapped in E2PROM
Description
Bits
Type
RW MOSI_SDA pad slope control
7
sda_slopectrl
‘0’ for standard and fast I2C mode, and high speed mode if VSUP < 1.8V
‘1’ for high speed mode if VSUP > 1.8V
6
wake_up_deb_en
RW When at '1' the wake-up debouncer is enabled
5:4
wake_up_edge_cfg
RW “00” (0x0): Forbidden
“01” (0x1): wake-up on falling edge
“10” (0x2): wake-up on rising edge
“11” (0x3): wake-up on both edge
3
2
usb_frc_hrv_low_hiz
usb_frc_bat_low_hiz
usb_crt_src_sel
RW
RW
1:0
RW
Table 5-14 Wake-up terminal configuration register (0x13)
The “sleep state” duration is controlled through a 24-bit counter (reg_t_sleep_vsup[23:0]). VSUP supply can be interrupted for up to 4 hours,
with a granularity of 1 ms.
t_sleep_vsup = reg_t_sleep_vsup[23:0]/1000 seconds
When VSUP is in “sleep state” it is possible to ground VSUP to create a known voltage level on the main controller supply, by setting
reg_ldo_cfg.vsup_tied_low to ‘1’ (see above in page 17).
The VSUP “sleep state” is enabled by setting reg_pwr_mgt.sleep_vsup to ‘1’ (see Table 5-12 bit 0).
Register name: reg_t_sleep_vsup_lo
Bits Bit name Type
7:0 t_sleep_vsup_lo RW Sleep counter duration – least significant byte
Table 5-15 VSUP "sleep state" counter time-out Least significant byte (0x14)
Address: 0x14
Default value mapped in E2PROM
Description
Register name: reg_t_sleep_vsup_mid
Bits Bit name Type
7:0 t_sleep_vsup_mid
Address: 0x15
Default value mapped in E2PROM
Description
RW Sleep counter duration – byte 2
Table 5-16 VSUP "sleep state" counter time-out middle significant byte (0x15)
Register name: reg_t_sleep_vsup_hi
Bits Bit name Type
7:0 t_sleep_vsup_hi RW Sleep counter duration – most significant byte
Table 5-17 VSUP "sleep state" counter time-out Most significant byte (0x16)
Address: 0x16
Default value mapped in E2PROM
Description
5.6. LUX-METER
The device contains this specific element to determine ranges of current supplied by the harvesting element.
19
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
The lux-meter is able to run in three modes:
Fully automatic mode
Automatic range selection
Fully manual mode
In fully automatic mode (selected by writing ‘1’ in reg_lux_meter_cfg.lux_meter_auto_meas) the device determines the value range for the current
flowing in from the harvesting element. The result is available in the reg_lux_meter_result.lux_meter_result register field. The
reg_lux_meter_result.lux_meter_busy bit indicates that the measurement is still ongoing and that the result is not available yet.
In automatic range selection mode (selected by writing ‘1’ in reg_lux_meter_cfg.lux_meter_auto_rng) the EM8500 automatically determines the
optimal range, and measures the voltage at VDD_HRV for maximum precision. The reg_lux_meter_result.lux_meter_busy bit indicates that the
range search is complete. In this mode lux-meter continues to operate until user disabled by writing ‘0’ into the
reg_lux_meter_cfg.lux_meter_auto_rng.
The full manual mode allows the user to select the range. The mode is selected by writing on the bit reg_lux_meter_cfg.lux_meter_manu – ‘1’ to
activate the mode, and ‘0’ to deactivate it. The selection of the range is done through the reg_lux_meter_cfg.lux_meter_rng field.
In case a lux-meter action is requested with LTS and STS disconnected, VLTS < v_bat_min_lo or – in primary cell mode – when
reg_lts_cfg.prim_cell_connect = ‘0’ the action is disregarded and the result – in automatic mode – is invalid.
Register name: reg_lux_meter_cfg
Bit name Type Reset
Address: 0x1C
Description
Bits
7
–
–
0
0
Reserved
Start the automatic lux-meter measurement. The lux-meter is disabled
automatically when the measure is finished
6
lux_auto_meas
OS
5
4
lux_auto_rng
lux_manu
RW
RW
0
0
Enable the lux-meter, and search for the best range. It remains enabled
Enable the lux-meter in manual mode (range forced by reg_lux_meter_cfg.lux_lvl)
Target current level to be detected
"0000" (0x0)
"0001" (0x1)
"0010" (0x2)
"0011" (0x3)
"0100" (0x4)
"0101" (0x5)
"0110" (0x6)
"0111" (0x7)
"1000" (0x8)
"1001" (0x9)
"1010" (0xA)
"1011" (0xB)
"1100" (0xC)
"1101" (0xD)
"1110" (0xE)
"1111" (0xF)
1 µA
2 µA
4 µA
8 µA
15 µA
30 µA
60 µA
120 µA
0.25 mA
0.5 mA
1 mA
1.8 mA
3.2 mA
6 mA
3:0
lux_lvl
RW
0x0
11 mA
17 mA
Table 5-18 Lux Meter Configuration Register (0x1C)
20
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
Register name: reg_lux_meter_result
Bit name Type Reset
Address: 0x1D
Description
Bits
7:5
4
–
–
'000' Reserved
lux_meter_busy
RO
0
Indicates that the lux-meter is still searching for best range
Lux-meter range status (result in automatic measurement mode)
"0000" (0x0)
"0001" (0x1)
"0010" (0x2)
"0011" (0x3)
"0100" (0x4)
"0101" (0x5)
"0110" (0x6)
"0111" (0x7)
"1000" (0x8)
"1001" (0x9)
"1010" (0xA)
"1011" (0xB)
"1100" (0xC)
"1101" (0xD)
"1110" (0xE)
"1111" (0xF)
below 2 µA
from 2 µA to 4 µA
from 4 µA to 8 µA
from 8 µA to 15 µA
from 15 µA to 30 µA
from 30 µA to 60 µA
from 60 µA to 120 µA
from 120 µA to 0.25 mA
from 0.25 mA to 0.5 mA
from 0.5 mA to 1 mA
from 1 mA to 1.8 mA
from 1.8 mA to 3.2 mA
from 3.2 mA to 6 mA
from 6 mA to 11 mA
from 11 mA to 17 mA
above 17 mA
3:0
lux_meter_result
RO
0x0
Table 5-19 Lux-meter Result Register (0x1D)
5.7. USB CHARGING
The EM8500 is equipped with a USB power line input to supply the device and to charge has the energy bank elements.
When a voltage above Vusb_min is detected, a regulator between VDD_USB and VDD_STS is enabled. The regulated voltage is VUSB_REG. In addition
to the regulator, a current source is activated between VDD_USB and VDD_LTS. This function is controlled by the reg_ext_cfg register. Four user
selected level of charge current delivered to LTS are available (reg_ext_cfg.usb_crt_src_sel).
When VDD_USB is connected, pins HRV_LOW and BAT_LOW can be brought into HiZ state.
Register name: reg_ext_cfg
Bit name
Address: 0x13
Default value mapped in E2PROM
Description
Bits
7
Type
RW
RW
RW
RW
sda_slopectrl
6
wake_up_deb_en
wake_up_edge_cfg
usb_frc_hrv_low_hiz
5:4
3
‘1’ force HRV_LOW in Hi-Z state if usb_on = '1'
‘0’ HRV_LOW pin standard configuration
2
usb_frc_bat_low_hiz
usb_crt_src_sel
RW
‘1’ force BAT_LOW in Hi-Z state if usb_on = '1'
‘0’ BAT_LOW pin standard configuration
1:0
RW USB power current source selection
"00" (0x0)
"01" (0x1)
"10" (0x2)
"11" (0x3)
0 mA
5 mA
10 mA
20 mA
(do not charge)
Table 5-20 USB Configuration Register (0x13)
Warning: When VDD_LTS is to be disconnected from its load, the USB current injected into LTS must be set to 0 mA, otherwise the device
could be damaged.
5.8. MISCELLANEOUS FUNCTIONS
This chapter describes additional control functions related to the regulation loop.
5.8.1. SOFT RESET FUNCTION
The soft reset function restarts the EM8500 from its boot sequence. The behavior of the EM8500 is the same as in a normal boot sequence. A
soft reset is generated by setting the register reg_soft_res_word to 0xAB. This register is enabled only if reg_protect_key is set to 0xE2. If the
value of the reg_protect_key is different from 0xE2, the register reg_soft_res_word is set to 0x00.
The reg_protect_key register is reset by the soft reset. Creating a new soft sequence requires preloading the reg_protect_key again.
21
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
Register name: reg_soft_res_word
Bit name Type Reset
soft_res_word
Address: 0x1A
Description
Bits
7:0
RW
0x00 Force reset when set at 0xAB
Table 5-21 Soft reset register (0x1A)
Register name: reg_protect_key
Bit name Type Reset
Address: 0x1B
Description
Bits
Allow writing on reg_soft_res_word register when set at 0xE2
0x00 Allow writing on protected registers when set at 0x4B
Allow writing on E2PROM when set at 0xA5
7:0
protect_key
RW
Table 5-22 Protected registers key (0x1B)
5.8.2. REGISTER PROTECTION
The EM8500 functionality is determined by the content of the configuration registers (like the supervising levels or periods). The registers are
always accessible in read mode. Some registers are write protected against unwanted write operations.
The registers ranging is address space from 0x00 to 0x18 are write protected. Writing into these registers is enabled after setting reg_protect_key
to 0x4B.
Note: The reg_protect_key is reset at the end of the communication transaction (see §6 on page 22). It is necessary to set it on the same
communication transaction – on SPI keeping CS to ‘1’ or on I2C before putting a I2C stop.
Write access to the on-chip E2PROM is controlled by the same mechanism. Prior to a write operation into the E2PROM reg_protect_key must be
set to 0xA5.
5.8.3. LTS PROTECTION DISABLE
By default the EM8500’s monitors voltage levels, namely lower voltage limit, to prevent damage to the LTS energy storage element.
This protection can be disabled by setting register reg_lts_cfg.no_bat_protect leaving the system connected to LTS even when the voltage level
drops below v_bat_min. Disabling protection might be suitable for systems using super-caps or solid-state battery storage elements.
When LTS protection is active the EM8500 tries to start-up from LTS only once, if after booting it still detects that VLTS < v_bat_min it enables the
protection and never try to restart from LTS. The system will then re-start as from a standard cold-start.
5.8.4. DCDC OFF FORCING
It is possible to stop the regulation loop by explicitly forcing the DCDC to stop its pumping operation. To stop the DCDC it is necessary to set the
bit reg_pwr_mgt.frc_prim_dcdc_dis to ‘1’ (see Table 5-12). De-asserting this bit (write it to ‘0’) will re-enable the DCDC to its normal operation.
6.
SERIAL INTERFACE
The EM8500 offers SPI and I2C serial interfaces selected by the CS pin.(see §6.2.1).
The configuration/function of the EM8500 is updated only after the end of a communication transaction. An SPI transaction is defined by all the
bytes sent and received when the pad CS is kept to ‘1’. An I2C transaction is defined by all the data sent or received between a start and a stop
I2C patterns.
Data synchronization between the communication interface and the internal part of the device is done at the end of a supervising loop. New
information is active two milliseconds after the end of the transaction. All write transactions sent before the end of this synchronization interval are
ignored. It is recommended to perform the device configuration in one transaction. Read transactions are allowed at any time.
6.1. I2C INTERFACE
The I2C slave interface is compatible with Philips I2C Specification version 2.1 (see specific timings on electrical specifications chapter). All modes
(standard, fast, high speed) are supported. MOSI_SDA and SCL pins are not strictly open-drain (they represent diodes to VSUP).
The 7-bit device address is defined in the E2PROM (at address 0x58). This address is copied at boot into the reg_spi_i2c_cfg.ic2_addr register
field.
The I2C bus uses the 2 wires SCL (Serial Clock) and MOSI_SDA. CS has to be connected to VSS. MOSI_SDA is bi-directional with open drain to
VSS: it must be externally connected to VSUP via a pull up resistor.
The I2C interface supports single and multiple read and write transactions.
In the following figures, “S” indicates the I2C transaction start, “P” indicates the I2C transaction stop.
The multi-read and multi write transactions are described in the following figures.
22
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
ACKS
ACKS
ACKS
MOSI_SDA
SCL
Address/data couple to be
written
i2c address
Register address (n)
Register value to be written @ n
P
S
Write
Figure 6-1: I2C write (multiple transactions)
To access registers in read mode, first address should first be send in write mode. Then a stop and a start conditions must be generated and
data bytes are transferred with automatic address increment:
ACKS
ACKS
MOSI_SDA
SCL
i2c address
Register address (n)
Write
ACKS
ACKM
NOACKM
MOSI_SDA
SCL
i2c address
P
Register read @ n+1, n+2, ...
Register read @ n
Figure 6-2: I2C read (multiple transactions)
S
Read
In the case of a read transaction, it is possible to avoid stopping and starting again a new transaction by following the register address with a
repeated start.
6.2. SPI INTERFACE
The SPI interface is a standard Serial to Peripheral Interface. It is compatible with two of the four standard transmission modes. The automatic
selection between the two modes ([CPOL=’0’ and CPHA=’0’] and [CPOL=’1’ and CPHA=’1’]) is determined by the value of SCL after the CS rising
edge.
The SPI interface can be used in 4-wire or 3-wire. The 3-wire is selected by setting the register reg_spi_i2c_cfg.spi_3w_en to '1’. The pin MOSI
is used as a data pin in 3-wire mode.
The SPI interface is a byte-oriented transmission interface. The first byte sent is contains the address of the register and access type of the
transmission – on the first transmitted bit (reads register – ‘1’ – or writes register – ‘0’). The following bytes contain register values. On read access
the address read is incremented for each additional byte until the address 0x7F. When reaching this address, the devices internal address counter
wraps to 0x00 and starts to read again from this address.
In case of a write transaction the protocol is based on an interleaved scheme of address and data. The first byte contains a 7-bit address and the
write command (First sent bit of the first byte equal to ‘0’). The second byte contains data to be written to this address.
It is important to note that it is possible to send a set of write commands, followed by a multi read transaction within the same SPI transaction.
Once in read mode, write accesses are not possible anymore in the same SPI transaction.
The following example shows a write of some registers followed by a check of the data.
0x00
0x05
0x01
0x03
0x06
0x02
0x80
0x00
0x00
0x00
0x00
Set hrv_period to 1/8 Hz
Set hrv_meas to 128ms
Set the system in primary cell mode
Read registers 0x00 to 0x03
CS
SCL
MOSI_SDA
MISO
R_Wn
ST7
AD6
ST6
AD5
ST5
AD4
ST4
AD3
ST3
AD2
ST2
AD1
ST1
AD0
ST0
DI7
DI6
DI5
DI4
DI3
DO3
DI2
DO2
DI1
DI0
DO7
DO6
DO5
DO4
DO1
DO0
Figure 6-3 SPI transaction scheme CPOL=1, CPHA=1
23
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
CS
SCL
MOSI_SDA
MISO
R_Wn
ST7
AD6
ST6
AD5
ST5
AD4
ST4
AD3
ST3
AD2
ST2
AD1
ST1
AD0
ST0
DI7
DI6
DI5
DI4
DI3
DI2
DI1
DI0
DO7
DO6
DO5
DO4
DO3
DO2
DO1
DO0
Figure 6-4 SPI transaction scheme CPOL=0, CPHA=0
CS
SCL
address
status
address
data to be written
data to be written
MOSI_SDA
MISO
data to be written in 'x',
output at '0'
address "x", access type (write)
and status byte
Next address/data couple
other address/data couple
MOSI_SDA
MISO
address "n"
status
data @ n
data @ n+1
data @ n+2
data @ x
address "x", access type (read)
and status byte
Figure 6-5 Multi register access transaction
Along with the address information the SPI interface sends the status register (reg_status – address 0x22) as the first response byte. In the case
of the 3-wire mode the protocol is identical to the I2C interface, and doesn’t allow having the status byte when sending the address to the device.
Interface signals are the following:
CS
SCL
MOSI_SDA
MISO
chip select, active high
clock
data input; data input/output in 3-wire mode
data output; Hi-Z level in 3-wire mode
6.2.1. INTERFACE SELECTION
The interface selection process is done through the use of the CS pin.
At reset (at the end of the boot sequence) the default interface selection is I2C. The SPI selection is done by asserting the CS pin. After CS
assertion the SPI interface is selected until the device is shut-down (VSTS below Vcs_lo).
If the CS pin is continuously asserted (through a hard connection to VSUP) the SPI interface is permanently selected. I2C is not available in this
case.
Register name: reg_spi_i2c_cfg
Address: 0x18
Default value mapped in E2PROM
Description
Bits
7
Bit name
spi_3w_en
Type
RW Set the SPI in its 3 wire mode (shared MOSI/MISO)
RW i2c address
6:0
i2c_addr
Table 6-1 SPI/I2C configuration register (0x18)
6.3. E2PROM
6.3.1. ACCESSING THE E2PROM
The on-chip E2PROM contains the default working parameters of the device. The E2PROM address space is mapped into the EM8500 register
map from address 0x40 (E2PROM address 0) to 0x7F ((E2PROM address 63). Some addresses are reserved (0x76 to 0x7F) and are accessible
in read-only mode by the user; some contains the defaults values – as described on §8. All other addresses can be freely used.
The user can write on the E2PROM at any time. Note that no protection is built in to prevent incomplete write transaction caused by a lack of
energy (STS too low). The user must ensure that the EM8500 is able to properly finish a write transaction.
Read and write accesses are performed through the serial interface. In difference to standard registers (addresses 0x00 to 0x3F), an E2PROM
access requires a dead time. A read access needs a dead time between read address and the data. A write access requires a dead time after
having sent the write data.
24
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
CS
SCL
MOSI_SDA
MISO
Tee_rd
Figure 6-6 SPI transaction for reading the E2PROM (CPOL=1)
CS
SCL
MOSI_SDA
MISO
Tee_rd
Figure 6-7 SPI transaction for reading the E2PROM (CPOL=0)
CS
SCL
MOSI_SDA
MISO
address "n"
status
address "m"
data @ n
status
data @ m
Tee_rd
Tee_rd
Thd_rd
Table 6-2 SPI multiple E2PROM read transactions
CS
SCL
0x1B
0xA5
E2PROM address
data
0x1B
0xA5
E2PROM address
data
MOSI_SDA
MISO
status
status
Tee_wr
Tee_wr
Figure 6-8 Two consecutive single E2PROM write SPI transactions
CS
SCL
MOSI_SDA
MISO
0x1B
0xA5
E2PROM address
data
E2PROM address
data
status
Tee_wr
Tee_wr
Figure 6-9 SPI multi-byte transaction for writing the E2PROM
When the I2C serial interface is used only single action per transaction is allowed when accessing the E2PROM. As for an SPI transaction a
dead time are necessary. Prior to a write transaction into the E2PROM it is necessary to set the reg_protection_key register to 0xA5.
For a write transaction, no other I2C transaction into the E2PROM address area is allowed for Twr_ee after the end of the write transaction. A
transaction inside this time window is ignored by the device.
In the following diagram responses from EM8500 are shown in red, data from the I2C master in black.
The following abbreviations are used:
W
R
S
Write transaction request
Read transaction request
Start an I2C transaction
25
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
P
A
N
Stop an I2C transaction
I2C Acknowledge
I2C Non Acknowledge
S
I2C address
W
0x1B
0xA5
reg address
reg data
P
S
I2C address
W
0x1B
0xA5
reg address
A
reg data
P
A
A
A
A
A
A
A
MOSI_SDA
SCL
Tee_wr
Tee_wr
Figure 6-10 I2C transaction for writing on the E2PROM
For a read transaction a dead-time (Trd_ee) has to be inserted in between the address setting transaction and the read action itself.
S
I2C address
W
A
Register address
A
P
S
I2C address
R
A
Read data
N P
MOSI_SDA
SCL
Tee_rd
Figure 6-11 I2C transaction for reading the E2PROM
26
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
7.
TYPICAL CHARACTERISTICS
Figure 7-1 Charger Efficiency vs Input Voltage (IIN = 10µA)
Figure 7-3 Charger Efficiency vs Input Voltage (IIN = 100µA)
Figure 7-5 Charger Efficiency vs Input Voltage (IIN = 1mA)
Figure 7-2 Charger Efficiency vs Input Current (VIN = 1.5V)
Figure 7-4 Charger Efficiency vs Input Current (VIN = 0.5V)
Figure 7-6 Charger Efficiency vs Input Current (VIN = 0.2V)
27
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
8.
REGISTER MAP
Table 8-1 Register summary with default value defined in E2PROM
28
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
Table 8-2 Register summary – No E2PROM default values
29
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
Table 8-3 E2PROM default values memory mapping
30
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
9.
TYPICAL APPLICATIONS
9.1. SAMPLE SCHEMATICS
9.1.1. SOLAR CELL ASSISTED SYSTEM
L1
LX1
EM8500
VDD_HRV
VDD_STS
CHRV
CSTS
VSS_DCDC
VDD_USB
VREG
Cold-start Booster
WAKE_UP
VDD_LTS
CREG
CLTS
VSUP
MPPT
Boost
Controller
controller
MOSI_SDA
MISO
Battery
(typically secondary cell)
VAUX[2]
SCL
CSUP
HOST
MCU
CS
VAUX[1]
VAUX[0]
BAT_LOW
HRV_LOW
Peripheral
(sensor, RF
transmitter, …)
Charge control and
supervisory
VAUX_GND[2]
VAUX_GND[1]
VAUX_GND[0]
CAUX0
Other
peripherals
VSS
I2C interface
SPI interface
Figure 9-1 Example of Application with a Solar Cell Harvester
Symbol
Component
Booster inductor
Harvester capacitor
STS capacitor
Regulator capacitor
Value
L1
47µH
4.7µF
47µF
470 nF
1 µF
CHRV
CSTS
CREG
CSUP
CAUX2
Main supply output capacitor
Auxiliary (2) supply output capacitor
1 µF
Table 9-1 Component list for solar cell application
31
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
9.1.2. TERMO-ELECTRICAL GENERATOR (TEG) ASSISTED SYSTEM
L1
LX1
EM8500
VDD_STS
CSTS
VDD_HRV
CHRV
TEG
VSS_DCDC
VDD_USB
VREG
WAKE_UP
VDD_LTS
Cold-start Booster
CLTS
CREG
Battery
(typically secondary cell)
VSUP
MPPT
Boost
Controller
controller
Peripheral
(sensor, RF
transmitter, …)
MOSI_SDA
MISO
VAUX[0]
VAUX[1]
SCL
HOST
MCU
CSUP
CS
CAUX0
BAT_LOW
HRV_LOW
Charge control and
supervisory
Wake-up
sensor
VAUX[2]
CAUX2
VAUX_GND[2]
VAUX_GND[1]
VAUX_GND[0]
VSS
SPI interface
Figure 9-2 Example of Application with a Thermo-electrical Generator (TEG) Harvester
Component
Symbol
Value
Booster inductor
Harvester capacitor
STS capacitor
Regulator capacitor
Main supply output capacitor
Auxiliary (0) supply output capacitor
Auxiliary (2) supply output capacitor
L1
47µH
4.7µF
47µF
470 nF
1 µF
CHRV
CSTS
CREG
CSUP
CAUX0
CAUX2
1 µF
1 µF
Table 9-2 Component list for TEG application
9.2. INDUCTOR SELECTION
The boost DCDC converter requires a properly selected inductor to obtain highest efficiency. Apart from the typical value of the inductor (47 µH
± 20%), coil saturation current and the internal resistivity need to be considered.
The saturation current should be at least 30% higher than the maximum peak current. The internal resistivity should be as low as possible –
a typical value of 0.65 Ω is suitable.
9.2.1. REFERENCE INDUCTORS
Size
RDC
Manufacturer
TDK
Part number
Comments
Length Width Thickness
Typ
560mΩ
1.25Ω
2.5Ω
Max
4mm
3mm
4mm
3mm
2.4mm
1.2mm
0.8mm
644mΩ VLCF4024T-470MR44-2
High efficiency performances
TDK
1.5Ω
VLS3012ET-470M
CBMF1608T470K
TAIYO YUDEN
1.6mm 0.8mm
Up to 500uW and Vhrv 1V max
Table 9-3 List of reference inductors
32
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
9.3. CAPACITOR SELECTION
The selection of the capacitor is strongly linked to the hysteresis value set in the configuration registers. Please refer to the application notes for
capacitors values for different system applications scenarios.
10. ORDERING INFORMATION
Part Nb
Package form
Delivery form
EM8500-A001-LF24B+
QFN24 4x4 mm
Tape & Reel
Table 10-1 Ordering Information
For other delivery format please contact EM Microelectronics representative.
11. PACKAGE INFORMATION
11.1. QFN24 4X4 PACKAGE
QFN24 4x4mm
D
MIN
NOM
MAX
e
L
0.5
0.45
0.18
2.5
0.5
0.55
0.3
b
0.25
2.6
D2
E2
A
2.7
E
2.5
2.6
2.7
0.85
0.02
0.20
0.20min
4.0
0.9
A1
A3
K
0.05
TOP VIEW
D
A
E
4.0
A3
A1
SIDE VIEW
L1
0.15max
ALL DIMENSIONS ARE IN MILLIMETERS
D2
K
D2/2
SEE DETAIL "A"
L
E2/2
5 * e
E2
K
TERMINAL/SIDE
2
1
L
L1
b
e
PIN #1 ID
e
SEE DETAIL "A"
e/2
DETAIL "A"
TERMINAL TIP
5 * e
BOTTOM VIEW
Figure 11-1 QFN24 Mechanical Information
11.1.1. PACKAGE MARKING
This section reports the package marking for EM8500. Additional marking letters and numbers are used for lot traceability.
8
0
5
1
0
0
0
33
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
EM8500
EM Microelectronic-Marin SA (“EM”) makes no warranties for the use of EM products, other than those expressly contained in EM's applicable
General Terms of Sale, located at http://www.emmicroelectronic.com. EM assumes no responsibility for any errors which may have crept into
this document, reserves the right to change devices or specifications detailed herein at any time without notice, and does not make any
commitment to update the information contained herein.
No licenses to patents or other intellectual property rights of EM are granted in connection with the sale of EM products, neither expressly nor
implicitly.
In respect of the intended use of EM products by customer, customer is solely responsible for observing existing patents and other intellectual
property rights of third parties and for obtaining, as the case may be, the necessary licenses.
Important note: The use of EM products as components in medical devices and/or medical applications, including but not limited to,
safety and life supporting systems, where malfunction of such EM products might result in damage to and/or injury or death of
persons is expressly prohibited, as EM products are neither destined nor qualified for use as components in such medical devices
and/or medical applications. The prohibited use of EM products in such medical devices and/or medical applications is exclusively at
the risk of the customer.
34
www.emmicroelectronic.com
Copyright 2017, EM Microelectronic-Marin SA
8500-DS, Version 2.1, 24-May-17
420005-A01, 2.0
相关型号:
©2020 ICPDF网 联系我们和版权申明