LTC1729_1 [Linear]
Li-Ion Battery Charger Termination Controllers; 锂离子电池充电器控制器终止
| 型号： | LTC1729_1 |
| 厂家： | 
Linear |
| 描述： | Li-Ion Battery Charger Termination Controllers |
| 文件： | 总16页 (文件大小：222K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTC1729 Series
Li-Ion Battery Charger
Termination Controllers
U
FEATURES
DESCRIPTIO
The LTC®1729 series is a family of smart termination
controllers for lithium-ion battery chargers. These ICs
providetricklechargepreconditioning,temperaturecharge
qualification, time or charge current termination, auto-
matic charger and battery detection and status output.
Combining the LTC1729 series part with the LT®1510
(1.5A), LT1769 (2A), LT1511 (3A) and LT1505 (>4A)
step-down chargers is a simple operation. Connecting six
pins from the LTC1729 series part to the step-down
chargers completes the integration. The LTC1729 termi-
nation controllers are also compatible with step-down/
step-up(SEPIC)chargers,includingtheLT1512(2Aswitch)
and LT1513 (3A switch).
■
Built-In Termination: 3-Hour Time-Out
■
C/10 Detection with Status Indicator
■
Trickle Charge Preconditioning If Cell <2.7V
■
Charging Enabled When 0°C < T < 50°C
■
Automatic Charger Present Detection
■
Automatic Battery Present Detection
■
1- or 2-Cell, 4.1V/Cell or 4.2V/Cell Options
■
Precision Internal 0.2% Voltage Feedback Divider
■
Compatible with LT1505/LT1510/LT1511/
LT1512/LT1513/LT1769
Small Footprint/Low Profile
■
U
APPLICATIO S
■
Cellular Phones
The LTC1729 series is available in the 8-pin MSOP and SO
packages.
■
PDAs
■
Cradle Chargers
Camcorders
, LTC and LT are registered trademarks of Linear Technology Corporation.
■
U
TYPICAL APPLICATIO
MBRM120T3
INPUT POWER
8.2V TO 20V
MBRM120T3
V
SW
CC
C
IN
*
1µF
6.19k
LT1510-5
PROG
10µF
0.22µF
300Ω
L1**
BOOST
GND
10µH
1k
V
C
MMBD914L
0.1µF
OVP
SENSE
BAT
+
+
C
***
OUT
4.2V
22µF
LTC1729-4.2
1
2
3
4
8
7
6
5
0.1µF
OVP
BAT
V
CC
1.4k
†
D1
CHARGE STATUS
V
C
1µF
200Ω
SENSE STATUS
GND NTC
1729 F01
10k NTC THERMISTOR, NTHS1206N02 VISHAY/DALE
NOTE: EITHER A THERMISTOR OR 10k RESISTOR MUST BE PRESENT
* TOKIN OR MARCON SURFACE MOUNT
** COILTRONICS TP3-100, 10µH, 2.2mm HEIGHT
(0.8A CHARGING CURRENT)
OPTION: TIE RESISTOR TO STATUS FOR
CHARGE TERMINATION AT
LOW CHARGING CURRENT
COILTRONICS TP1 SERIES, 10µH, 1.8mm
HEIGHT (<0.5A CHARGING CURRENT)
*** PANASONIC EEFCD1B220
†
LUMEX SML-LX0805GW-TR
Figure 1. 500kHz Li-Ion Cell Phone Charger (0.8A)
1
LTC1729 Series
W W U W
ABSOLUTE AXI U RATI GS
(Note 1)
VCC ......................................................................... 30V
SENSE, VBAT, NTC .................................... –0.3V to 15V
VC ............................................................. –0.3V to 15V
OVP ............................................................ –0.3V to 5V
STATUS .................................................... –0.3V to 30V
Operating Temperature Range .................... 0°C to 70°C
Storage Temperature Range ................ –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
U W
U
PACKAGE/ORDER I FOR ATIO
ORDER PART
NUMBER
ORDER PART
NUMBER
TOP VIEW
LTC1729CMS8-4.1
LTC1729CMS8-4.2
LTC1729CMS8-8.2
LTC1729CMS8-8.4
LTC1729CS8-4.1
TOP VIEW
OVP
BAT
1
2
3
4
8
7
6
5
V
V
CC
C
LTC1729CS8-4.2
LTC1729CS8-8.2
LTC1729CS8-8.4
OVP
BAT
SENSE
GND
1
2
3
4
8 V
7 V
6 STATUS
5 NTC
CC
C
SENSE
GND
STATUS
NTC
MS8 PACKAGE
S8 PART MARKING
MS8 PART MARKING
8-LEAD PLASTIC MSOP
S8 PACKAGE
8-LEAD PLASTIC SO
TJMAX = 150°C, θJA = 200°C/ W
LTLY
LTJH
LTLZ
LTJG
172941
172942
172982
172984
TJMAX = 150°C, θJA = 150°C/ W
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C, VIN = 8V
LTC1729-4.1/LTC1729-4.2
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
DC CHARACTERISTICS
I
V
Supply Current
V
V
V
V
= 5V (Below UVLO)
●
●
1
5
12
2.0
21
µA
mA
mA
mA
CC
CC
IN
IN
IN
IN
= 8V, V
= 8V, V
= 8V, V
> 4.5V, No Bat
= 2.5V Trickle
= 3.5V Charge
1.0
10
0.5
1.4
17
3.0
BAT
BAT
BAT
●
●
●
5.0
V
V
V
V
V
Undervoltage Lockout High
Undervoltage Lockout Low
5.5
5.0
6.5
6.0
7.5
7.0
V
V
LKOH
LKOL
VBAT
IN
IN
I
Current
V
V
V
V
= 5V (Below UVLO), V = 4.2V
BAT
●
●
–1
40
–19
–2.7
– 0.1
73
–12
–1.3
1
µA
µA
mA
mA
BAT
IN
IN
IN
IN
= 8V, V
= 8V, V
= 8V, V
= 4.25V No Bat
= 2.5V Trickle
= 3.5V Charge
120
–9.5
–0.5
BAT
BAT
BAT
●
●
V
V
V
Clamp
No Bat (External 200µA Pull-Up on V )
BAT
4.25
4.5
4.75
V
CLAMP
MAX
BAT
High V
Threshold
Threshold
High Going Threshold
Low Going Threshold
●
●
4.25
4.25
4.51
4.50
4.75
4.75
V
V
BAT
V
Low V
High Going Threshold
Low Going Threshold
●
●
2.55
2.45
2.7
2.6
2.85
2.75
V
V
MIN
BAT
I
SENSE Pin Current
Charge State, V
= 3V
SENSE
●
●
85
100
115
µA
SENSE
V
SENSE Pin C/10 Offset
Charge State, V = (V
– V )
SENSE
±1
±2.5
mV
C10
C10
BAT
2
LTC1729 Series
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C, VIN = 8V
LTC1729-4.1/LTC1729-4.2
SYMBOL
PARAMETER
CONDITIONS
= 1V
MIN
TYP
MAX
UNITS
µA
I
NTC Pin Current
V
●
●
90
100
110
NTC
NTC
V
V
Thermistor Pin Reset Threshold
Thermistor Pin Hot Hold Threshold
0.160
0.206
0.240
V
NTC-RESET
NTC-HOT
High Going Threshold
Low Going Threshold
●
●
0.460
0.380
0.486
0.405
0.510
0.430
V
V
V
V
Thermistor Pin Cold Hold Threshold
OVP Pin Voltage
High Going Threshold
Low Going Threshold
●
●
2.70
2.10
2.79
2.23
2.90
2.35
V
V
NTC-COLD
OVP
V
= 4.1V or V
= 4.2V
●
2.455
2.460
2.465
2.465
2.475
2.470
V
V
BAT
BAT
V
V
Output Low Voltage-STATUS Pin
I = 3mA
●
●
●
0.5
0.35
40
0.9
0.6
50
1.2
0.75
65
V
V
OL-ST
OL-VC
SOFT
O
Output Low Voltage-V Pin
I = 1mA
O
C
I
Status Soft Pull-Down Current
V
= 4.5V
µA
STATUS
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C, VIN = 12V
LTC1729-8.2/LTC1729-8.4
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
DC CHARACTERISTICS
I
V
Supply Current
V
V
V
V
= 9V (Below UVLO)
●
●
1
6
12
2.0
21
µA
mA
mA
mA
CC
CC
IN
IN
IN
IN
= 12V, V
= 12V, V
= 12V, V
> 9V, No Bat
= 5V Trickle
= 7V Charge
1.0
10
0.5
1.4
17
3.0
BAT
BAT
BAT
●
●
●
5.0
V
V
V
V
V
Undervoltage Lockout High
Undervoltage Lockout Low
9.5
8.5
10.4
9.6
11.4
10.5
V
V
LKOH
LKOL
VBAT
IN
IN
I
Current
V
V
V
V
= 9V (Below UVLO), V = 8.4V
BAT
●
●
–1
60
–19
–2.7
–0.1
95
–12
–1.3
1
µA
µA
mA
mA
BAT
IN
IN
IN
IN
= 12V, V
= 12V, V
= 12V, V
= 8.5V No Bat
= 5V Trickle
= 7V Charge
140
–9.5
–0.5
BAT
BAT
BAT
●
●
V
V
V
Clamp
No Bat (External 200µA Pull-Up on V )
BAT
8.5
9
9.5
V
CLAMP
MAX
BAT
High V
Threshold
Threshold
High Going Threshold
Low Going Threshold
●
●
8.5
8.5
9.013
9
9.5
9.5
V
V
BAT
V
Low V
High Going Threshold
Low Going Threshold
●
●
5.1
4.9
5.4
5.2
5.7
5.5
V
V
MIN
BAT
I
SENSE Pin Current
Charge State, V
= 7V
●
●
●
●
85
100
±1
115
±2.5
110
µA
mV
µA
V
SENSE
SENSE
V
SENSE Pin C/10 Offset
NTC Pin Current
Charge State, V = (V
– V
)
SENSE
C10
NTC
C10
BAT
I
V
= 1V
90
100
NTC
V
V
Thermistor Pin Reset Threshold
Thermistor Pin Hot Hold Threshold
0.160
0.206
0.240
NTC-RESET
NTC-HOT
High Going Threshold
Low Going Threshold
●
●
0.460
0.380
0.486
0.405
0.510
0.430
V
V
V
V
Thermistor Pin Cold Hold Threshold
OVP Pin Voltage
High Going Threshold
Low Going Threshold
●
●
2.70
2.10
2.79
2.23
2.90
2.35
V
V
NTC-COLD
OVP
V
= 8.2V or V
= 8.4V
●
2.455
2.460
2.465
2.465
2.475
2.470
V
V
BAT
BAT
V
V
Output Low Voltage-STATUS Pin
I = 3mA
●
●
●
0.5
0.35
40
0.9
0.6
50
1.2
0.75
65
V
V
OL-ST
OL-VC
SOFT
O
Output Low Voltage-V Pin
I = 1mA
O
C
I
Status Soft Pull-Down Current
V
= 4.5V
µA
STATUS
3
LTC1729 Series
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are T = 25°C. (Note 2)
A
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
AC CHARACTERISTICS
TIMER1
TIMER2
TIMER3
TIMER4
Timer for Trickle-Charge Preconditioning
Timer for Charging
●
●
●
●
●
0.869
2.61
1
3
1.305
3.55
Hr
Hr
Timer for V
Timer for V
Filter
Filter
0.764
3.055
6.66
0.859
3.5
1.043
4.17
sec
sec
µs
MAX
C/10
t
Oscillator Period
7.63
9.09
OSC
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: V = 8V for LTC1729-4.1/LTC1729-4.2; V = 12V for
LTC1729-8.2/LTC1729-8.4
IN
IN
U W
TYPICAL PERFOR A CE CHARACTERISTICS
IVBAT vs Temperature (4.2V Version)
IVBAT vs Temperature (8.4V Version)
IVBAT vs VCC (4.2V Version)
14
12
10
8
14
12
10
14
12
10
V
BAT
= 2.5V
V
= 5V
BAT
V
= 2.5V
BAT
8
6
4
2
0
8
6
4
2
0
6
4
2
V
= 3.5V
BAT
0
25
50
100
22
30
0
75
6
10
14
18
(V)
26
25
50
100
0
75
TEMPERATURE (°C)
V
CC
TEMPERATURE (°C)
1729 G02
1729 G03
1729 G01
IVBAT vs VCC (8.4V Version)
ICC vs VCC (4.2V Version)
ICC vs VCC (8.4V Version)
14
12
10
8
14
12
12
10
V
BAT
= 5V
V
BAT
= 5V
V
= 2.5V
BAT
10
8
8
6
6
4
2
4
2
0
6
V
= 3.5V
4
V
= 7V
22
BAT
BAT
V
BAT
= 7V
2
10
14
18
22
(V)
26
30
10
14
18
26
30
6
10
14
18
22
26
30
V
CC
(V)
V
CC
V
(V)
CC
1729 G04
1729 G05
1729 G06
4
LTC1729 Series
U
U
U
PI FU CTIO S
OVP (Pin 1): Connection to an Internal Precision Resistor
Divider Used as a Voltage Feedback Monitor for Constant-
Voltage Mode Charging.
If the NTC pin is below 0.2V, the state machine is forced
in the reset mode with all the timers cleared to zero. The
current sources on the BAT pin and SENSE pin are
disabled leaving the 55k OVP divider. The STATUS pin is
pulled low in the Reset mode.
BAT (Pin 2): Input to Battery Monitor Circuits and OVP
Resistor Divider. The battery monitor circuits activate
trickle charge preconditioning, battery present detection
andC/10currentdetection. Thispinisinahighimpedance
state when VCC is below the undervoltage lockout thresh-
old. During trickle charge preconditioning and charging
the BAT pin sources 12mA and 1.3mA respectively. The
current sources are clamped from driving the BAT pin
above 4.5V/cell with an internal pull-down transistor.
There is a 100µA current source on the NTC pin to bias the
NTCthermistor.ThiscurrentsourceisactivewhentheVCC
is greater than the undervoltage lockout threshold.
STATUS (Pin 6): Open-Drain Output for C/10 Charge
Termination Detection Circuit. When in the Charge state,
thispinispulledlow. Oncethechargecurrentdropsbelow
the C/10 current threshold for three seconds, the pull-
down transistor is disabled, and a 50µA pull-down current
sink remains activated until the 1- or 3-hour time-out or
the battery or wall adapter is removed.
IntheNoBat, DoneandPausestatesortheHoldandReset
modes, thecurrentsourcesareturnedoff, leavingonlythe
55k OVP divider as a load on the BAT pin. Most chargers
have a 200µA current source that will compensate for this
50µA to 80µA load.
VC (Pin7):Open-DrainOutputforTurningOfftheCharger.
When this pin is open circuit, the charger is active.
Normally this pin allows the charger to be active for three
hours.
SENSE (Pin 3): Input to C/10 Current Detection Circuit.
Thispinsinks100µAduringtheChargestatewhichisused
to program the C/10 current threshold.
VCC (Pin 8): Input Supply. For 4.1V or 4.2V single cell
operation, VCC should be between 8V and 28V with the IC
turning off when VCC drops below 6V. For 2-cell applica-
tions, the undervoltage lockout is 10.4V with a minimum
VCC of 12V. Removing the wall adapter will trigger an
undervoltage lockout and put the IC in a high impedance
condition. When the supply is connected, the IC is initial-
izedintheResetmodewiththestatemachineforcedinthe
Charge state with all the timers set to zero.
GND (Pin 4): Ground.
NTC (Pin 5): Input to the NTC Thermistor Monitoring
Circuits. When the voltage on this pin is above 2.79V
(cold) or below 0.405V (hot), the state machine is locked
in the present state and the timer is stopped. This is called
the Hold mode. While in the Hold mode, the charger is
turned off via the VC pin and the current sources on BAT
and SENSE pins are turned off. The STATUS pin is not
affected.
5
LTC1729 Series
W
BLOCK DIAGRA
7
6
V
C
M2
M3
3
SENSE
UVLO
100µA
STATUS
–
COMP1
+
50µA
C/10
1.3mA
12mA
COMP2
COMP3
BAT
OVP
+
–
2
1
V
MAX
4.5V/CELL
CLAMP
LOGIC
AND
TIMER
UVLO
M1
4.5V/CELL
2.7V/CELL
2.465V
+
–
V
MIN
HOLD
100µA
COMP4
COMP5
COMP6
+
–
NTC
5
2.79V
+
–
0.405V
+
–
0.2V
RESET
1729 F02
Figure 2. Block Diagram
6
LTC1729 Series
W U U
APPLICATIO S I FOR ATIO
U
Comparator COMP1 is used to indicate C/10 charge cur-
rent threshold. (“C” is a term used to indicate the Ampere-
hour capacity of a cell.) Figure 3 details the C/10 detection
circuit. The resistor and capacitor on the SENSE pin filter
the signal from the 0.2Ω current sense resistor R1. The
100µA current sink on the SENSE pin develops 20mV
across the 200Ω resistor R2. This sets a 20mV offset on
COMP1 that sense resistor R1 must equal before C/10
currentisindicated.TheC/10isnotrecognizedbythelogic
until it passes through a 3-second digital filter.
Overview
The LTC1729 is a charge termination controller for the
LT1505/LT1510/LT1511/LT1512/LT1513/LT1769 con-
stant-voltage/constant-current battery charger family.
Table1detailsthesechargers.Theprimaryfunctionofthis
IC is to stop the charger after three hours of constant-
voltage/constant-current charging. The secondary func-
tion of this controller includes an indication when the
charge current (during constant-voltage mode) drops
below a user-selected threshold. A 500kHz Li-Ion cell
phonechargerisshowninFigure1. TheLTC1729requires
only six external components when combined with the
standard LT1510 application. The LTC1729 provides a
complete and tiny solution for cellular phones and other
portable applications.
Forcaseswheretherearemultiplebatteriestobecharged,
theLTC1729detectswhenabatteryisremovedandresets
the timers for the next charge cycle. The battery present
detection is the primary function of comparator COMP2.
When the battery is disconnected from the LTC1729, the
voltage at the BAT pin will begin ramping upward. This is
due to a current source inside the charger or an external
pull-up resistor. Once the voltage on the BAT pin exceeds
the 4.5V/cell limit, COMP2 signals a VMAX = true to the
logic and turns on a transistor that clamps the voltage.
Table 1. Battery Chargers
LT1505
LT1510
LT1510-5
LT1511
LT1512
LT1513
LT1769
4A Step-Down Charger with Input Current Limit
1.5A Step-Down Charger
1.5A 500kHz Step-Down Charger
3A Step-Down Charger with Input Current Limit
2A Switch SEPIC Charger
There is the possibility of an overvoltage transient at the
charging terminals. This occurs if the battery protection
circuit, which is often included in the battery pack, opens
the connection to the battery during high current charging
(constant-currentmode).Thisisaresultofenergystorage
intheinductor.COMP2sensestheovervoltageandclamps
the VC pin, reducing the duty cycle of the charger. If the
battery protection circuit quickly returns battery connec-
tion to the charger (in less than one second), then the
LTC1729 continues charging without resetting the timers.
3A Switch SEPIC Charger
2A Step-Down Charger with Input Current Limit
Block Diagram
Figure 2 shows the block diagram of the LTC1729. The IC
consists of six comparators, a resistive divider, a UVLO
block and a logic and timer block.
V
CC
CHARGING
CURRENT
LTC1729
CHARGE
LED
I
BIAS
100µA
20mV
STATUS
SENSE
BAT
–
+
–
+
LOGIC
AND
TIMERS
R2
200Ω
C1
1µF
R1
0.2Ω
3-SEC
FILTER
20mV
COMP1
+
50µA
–
1729 F03
Figure 3. C/10 Detection Circuit
7
LTC1729 Series
W U U
U
APPLICATIO S I FOR ATIO
Forabatterythathasbeendeeplydischarged,theLTC1729
provides a 12mA start-up current. This preconditioning
trickle charge begins when the battery voltage drops
below 2.7V/cell. Comparator COMP3 is used to determine
when this condition exists. The battery operating range is
summarized in Figure 4.
When the input supply is removed in step-down charger
designs, the VCC pin does not drop to 0V, but is held to a
diode drop below the battery voltage. This is due to the
internal parasitic diode from the SW pin to the VCC pin that
is present in the LT1510, LT1511, LT1769, and the body
diode of the top MOSFET in the LT1505 charger. Remov-
ing the input supply will result in the VCC pin dropping
belowtheUVLOthreshold,thusshuttingdowntheLTC1729
and minimizing battery drain. Once the input supply is
connected, the LTC1729 resets the timers and begins
another charge cycle. There is a disconnect transistor that
willremovetheOVPresistordividerfromthebatterywhen
the VCC voltage drops below the UVLO threshold.
With a 10k negative TC thermistor connected to the NTC
pin, the LTC1729 will disable charging if the temperature
is not in the 0°C to 50°C range. A thermistor must be
present at this pin, or if the temperature qualification
featureisnotused,a10kresistormustbeusedinitsplace.
This pin should not be left open. The NTC thermistor
monitoringcircuitsconsistofCOMP4,COMP5andCOMP6.
The NTC pin voltage range is shown in Figure 5.
If external circuitry is connected directly to the VCC pin and
the input power is removed, battery current will flow
through the charger’s internal parasitic diode (SW pin to
VCC pin), discharging the battery and possibly damaging
the charger if currents greater than 1A are present. If
external circuitry is used, connect it directly to the input
power source (which is the anode of the input Schottky
diode).
Comparators COMP4 and COMP5 signal the logic when
the temperature is below 0°C or above 50°C. The 100µA
bias current through the 10kΩ thermistor will generate
2.79V at 0°C and 0.405V at 50°C. The voltage hysteresis
on COMP4 and COMP5 is designed to give 10°C of
temperature hysteresis. If the voltage on the NTC pin
drops below 0.2V, the comparator COMP6 generates a
reset to the logic and timer block.
The logic and timer block consists of a state machine,
oscillator and counter. The state machine will be dis-
cussed in detail in the next section. The oscillator is
internallytrimmedto131kHz. Thecounteriscomposedof
a chain of 25 flip-flops that includes self-test circuitry.
To provide accurate charge voltages, the internal resistor
divider is trimmed to provide a precise ±0.2% voltage of
2.465V at the OVP pin for the four battery voltage options
of 4.1V, 4.2V, 8.2V and 8.4V.
HOLD MODE
2.79V
V
V
= 1V
= 0V
BATTERY CLAMP
PULL-DOWN
ON
NORMAL CHARGE
MAX
MIN
4.5V/CELL
0.405V
V
MAX
V
MIN
= 0V
= 0V
HOLD MODE
NORMAL CHARGE
2.7V/CELL
0.2V
V
MAX
V
MIN
= 0V
= 1V
TRICKLE CHARGE
PRECONDITIONING
RESET MODE
1729 F05
1729 F04
Figure 4. BAT Voltage Operating Range
Figure 5. NTC Voltage Operating Range
8
LTC1729 Series
W U U
U
APPLICATIO S I FOR ATIO
State Machine
Reset and Hold are the two modes that will cause the
chargertostopcharging(VC pinpulledlow)andignorethe
state machine. The Reset mode clears all the timers and
forces the state machine to begin in the Charge state
(STATUS pin pulled low). This mode is only activated
momentarilyatpower-uporwhentheNTCpinisbelowthe
Reset threshold. The other interrupt condition is called the
Hold mode. When the voltage on the NTC pin is above
2.79V (cold) or below 0.405V (hot), the state machine is
lockedinthepresentstateuntiltheNTCpinvoltagereturns
to the proper range. While in the Hold mode, the charging
is disabled and the timers are frozen.
The state machine is responsible for the following items:
1. When to start and stop the charger. The internal timer
must be initialized every time a new battery is installed
or when the input supply is applied.
2. When a battery is installed, the state machine must
determine if it is a new battery or if the previous battery
has been reinstalled.
3. When a deeply discharged battery is installed, trickle
charge conditioning must take place before the full
charge current.
The charger is enabled only during the charger “ON” state.
There are three ways that the state machine can exit the
charger“ON”state. Thefirstisfora3-hourtime-outwhich
is denoted as the time > tMAX transition to the Done state.
The state machine diagram is shown in Figure 6. Note that
the Charge state includes the Precondition state, the
charger “ON” state and the Reset mode.
CHARGE
RESET MODE
I
= 0
BAT
STATUS = PULL-DOWN
V
C
= PULL-DOWN
V
< V
V
> V
BAT MIN
BAT
MIN
NOTE: FOR STATUS
PULL-DOWN = HARD:
FOR CURRENT > C/10
PULL-DOWN = 50µA:
FOR CURRENT < C/10 FOR 3SEC
PRECONDITION
= 12mA
V
V
> V
< V
CHARGER “ON”
= 1.3mA
BAT
MIN
MIN
I
I
BAT
BAT
STATUS = PULL-DOWN
= PULL-DOWN
STATUS = PULL-DOWN
= OPEN
BAT
V
C
V
C
t
= 1HR
t
= 3HR
MAX
MAX
V
< V
MAX
BAT
TIME > t
V
> V
MAX
= 0
BAT
MAX
FOR MORE THAN 1SEC
PAUSE
= 0
DONE
BAT
V
< V
BAT
MAX
I
I
BAT
FOR MORE THAN 1SEC
STATUS = PULL-DOWN
= PULL-DOWN
STATUS = OPEN
V
C
V
C
= PULL-DOWN
V
> V
MAX
V
BAT
> V
MAX
BAT
FOR MORE THAN 1SEC
FOR MORE THAN 1SEC
NO BAT
BAT
STATUS = OPEN
= PULL-DOWN
I
= 0
V
C
V
NTC
V
NTC
> 2.79V OR
< 0.405V
V
NTC
V
NTC
< 2.79V AND
> 0.405V
HOLD MODE
= 0
I
BAT
STATUS = PREVIOUS STATUS
= PULL-DOWN
V
C
1729 F06
Figure 6. State Diagram
9
LTC1729 Series
W U U
U
APPLICATIO S I FOR ATIO
Second, if the battery is removed from the charger, the
VMAX signal is activated as mentioned in the Block Dia-
gram section. This causes the state machine to make the
Status Output Pin
The STATUS pin is designed to provide an indication that
the battery is charging. Once the current drops below the
C/10 threshold, the battery is close to being fully charged.
The LTC1729 turns off the hard pull-down once the
C/10 comparator is active for more than three seconds.
The 50µA soft pull down remains in effect until the 3-hour
time-out is completed or the input power is removed.
V
BAT > VMAX transition to the Pause state. The third way to
exit the charger “ON” state is with a VBAT < VMIN transition
to the Precondition state. The battery will need to drop
below 2.6V/cell to be less than VMIN. This is not a likely
scenario.
Once in the Pause state, there are two ways to proceed.
The first is to go to the No Bat state. This requires that the
VBAT remain greater than VMAX for more than one
second. From these conditions, the LTC1729 interprets
that a battery has been removed. If the voltage on the BAT
pin stays less than VMAX for more than one second, then
the state machine returns to the Charge state (Precondi-
tionandcharger“ON”).Thisisinterpretedasamomentary
open caused by the battery pack protection circuitry or
loose contact.
By using two different value pull-up resistors, a micropro-
cessor can detect three states from this pin (charging,
C/10 and stop charging). See Figure 7.
V
IN
V
DD
8
V
CC
µPROCESSOR
200k
3k
LTC1729
STATUS
6
OUT
IN
The Done state can only proceed to the No Bat state. From
outside the LTC1729 this transition is undetectable. The
requirement for this transition is for the BAT pin voltage to
exceed VMAX for more than one second. The IC now
assumes that the battery has been removed.
1729 F07
Figure 7. Microprocessor Interface
When the LTC1729 is in charge mode, the STATUS pin is
pulled down by an internal N-channel MOSFET. To detect
this mode, force the digital output pin, OUT, high and
measure the voltage at the STATUS pin. The N-channel
MOSFET will pull the pin low even with a 3k pull-up resis-
tor. Once the charge current drops to 10% of the full-scale
current (C/10), the N-channel MOSFET is turned off and a
50µA current source is connected to the STATUS pin. The
IN pin will then be pulled high by the 3k pull-up. By forcing
the OUT pin into a high impedance state, the current
source will pull the pin low through the 200k resistor.
When the internal timer has expired, the STATUS pin will
change to high impedance state and the 200k resistor will
thenpullthepinhightoindicatethecharginghasstopped.
FromtheNoBatstate,thereisonlyonepossibletransition.
TheNoBatstatecanmovetotheChargestateifthevoltage
ontheBATpinremainslessthanVMAX foronesecond.The
LTC1729 will now work on the assumption that a new
battery has been installed.
Although the Precondition and Charger “ON” both reside
in the Charge state, there are differences between these
states. The main purpose of the Precondition state is to
slowlybringaheavilydischargedbatteryuptoaminimum
level before full charge current begins. The Precondition
state uses a 12mA current source to trickle charge the
battery with a 1-hour time-out transition to the Done state.
The Charger “ON” state enables the external charger and
the time-out is increased to three hours. For the entire
time in the Precondition state, the STATUS pin uses a hard
pull-down. In the Charger “ON” state the STATUS pin uses
two types of pull-down: hard pull-down and soft 50µA
pull-down.
Terminate at C/10 Current
Charging can also be terminated using C/10 detection
before the 3-hour time-out. By connecting the low side of
the NTC thermistor to the STATUS pin instead of ground,
10
LTC1729 Series
W U U
APPLICATIO S I FOR ATIO
theNTCpinwillfloatto5VassoonastheStatuspull-down
is open. This will force the state machine into the Hold
mode. TheVC pinispulledlowwhichturnsoffthecharger.
This circuit is shown in Figure 8.
U
current). This C/10 number is not fixed, but is set by an
external resistor connected to the LTC1729 SENSE pin. A
100µA bias current through this resistor develops a volt-
age which is compared with the voltage across the charge
current sense resistor. When these voltages are equal, the
open-drain STATUS pin turns off. Connecting an LED to
the STATUS pin will give a visual indication during the
precondition trickle charge and the portion of the main
charge before C/10 has occurred.
In order to restart the charging process for a new battery,
the NTC pin will need to be momentarily brought below
0.2V or the VCC pin brought below the UVLO threshold.
The automatic battery detection features are disabled
during the Hold mode.
By reducing the LTC1729 SENSE pin resistor to 0Ω, the
STATUS pin function can be changed to a charging indica-
tor (Figure 9). The LED on the STATUS pin will always go
off after the 3-hour charge cycle is completed, regardless
of the C/10 circuitry.
Using Status as a Charging Indicator
In many applications circuits shown in this data sheet, the
STATUS pin is used to indicate when C/10 has occurred
(charge current has dropped to 10% of the full charge
LTC1729-4.2
1
2
3
4
8
V
CC
OVP
BAT
OVP
BAT
V
CC
0.1µF
7
6
5
V
C
V
C
1µF
200Ω
SENSE
SENSE STATUS
GND NTC
10k NTC THERMISTOR
NTHS1206N02 VISHAY/DALE
1729 F08
Figure 8. Terminate Charging at C/10
CHARGE
CURRENT
LTC1729
100µA
I
BIAS
SENSE
BAT
–
+
–
SENSE
RESISTOR
COMP1
+
1729 F09
Figure 9. Modify C/10 Indication to Create Charging Indicator
11
LTC1729 Series
U
TYPICAL APPLICATIO S
Wide Input Voltage Range 1A Charger
L1**
V
Si9925
C2*
4.7µF
IN
D1
+
BOOST
V
3V TO 28V
MBRS340
+
D2
C3
22µF
+
V
CAP
OSC
LV
V
1/2 BAT85S
IN
SW
+
C1
22µF
×2
LTC1044
GND
D3
L2**
1/2 BAT85S
R1
29.4k
ON/OFF
S/S
LT1512
–
CAP
V
OUT
+
V
I
FB
FB
R4 39Ω
10µF
R2
12.4k
GND
V
C
R3
0.1Ω
C4
0.33µF
R5
470Ω
C5
0.1µF
R6
0.1Ω
8.4V
R
PULL-UP
47k
LTC1729-8.4
OVP
BAT
SENSE STATUS
GND NTC
+
C7
10µF
220k
V
CC
R7 C6
100Ω 1µF
V
C
1729 TA01
R8:10k NTC THERMISTOR, NTHS1206N02 VISHAY/DALE
NOTE: EITHER A THERMISTOR OR 10k RESISTOR MUST BE PRESENT
R8
* TOKIN CERAMIC 1E225ZY5U-C203-F
** L1, L2 ARE TWO 10µH INDUCTORS: SUMIDA CDRH6D38-100
Using STATUS Pin to Indicate Charge Status
TO V
CC
12V
8
7
6
5
V
CC
0.1µF
2.2k
CONDITION
NO WALL ADAPTER
CHARGING (I
CHARGING (I
TIMER EXPIRED
AMBER GREEN
V
C
47k
OFF
ON
OFF
OFF
OFF
OFF
ON
LTC1729
10k
> C/10)
< C/10)
BAT
BAT
STATUS
NTC
ON
2k
4.7k
2k
1729 TA03
PNP: MMBT3906
AMBER LED
GREEN LED
12
LTC1729 Series
U
TYPICAL APPLICATIO S
4A, 2-Cell Lithium-Ion Battery Charger
TO
SYSTEM
LOAD
DBODY
R
M3
S4
C4
0.1µF
V
0.025Ω
IN
Si4435
D3
(FROM
MMSD4148
+
C *
IN
ADAPTER)
47µF
R7
500Ω
C1
1µF
C3
V
BOOSTC
BOOST
CC
35V
D2
C2
2.2µF
GBIAS
MMSD4148
0.68µF
M1
R
CLN
CLP
S1
TGATE
SW
Si4412
0.025Ω
5Ω
R5
3k
+
C
22µF
× 2
***
L1**
15µH
M2
Si4412
OUT
INFET
UV
D4
MBRS140
BGATE
LT1505
+
V
C
SYNC
SHDN
FLAG
CAP
8.4V
R4
3k
C5
R6
PROG
5.1k
R
4.93k
1%
PROG
3 CELL
0.33µF
V
FB
4.2V
4.1V
COMP1
R
R
S3
S2
R3
R1
1k
C7
0.68µF
200Ω
200Ω
300Ω
1%
1%
AGND
†
C
1µF
C6
PROG
PGND
0.1µF
BAT2 BAT SENSE SPIN
R
PULL-UP
10k
LTC1729-8.4
OVP
BAT
V
CC
R9
C9
0.1µF
1.4k
V
C
††
D5
C8
0.1µF
SENSE STATUS
GND NTC
R8
100Ω
10k NTC THERMISTOR, NTHS1206N02 VISHAY/DALE
NOTE: EITHER A THERMISTOR OR 10k RESISTOR MUST BE PRESENT
* SANYO OS-CON
** SUMIDA CDRH127-150
OPTION: TIE RESISTOR TO STATUS FOR
CHARGE TERMINATION AT
LOW CHARGING CURRENT
*** AVX TPSD226L025R0200
†
C6 NOT NEEDED IF FLAG NOT USED
LUMEX SML-LX0805GW-TR
1729 TA02
††
13
LTC1729 Series
U
PACKAGE DESCRIPTIO
Dimensions in inches (millimeters) unless otherwise noted.
MS8 Package
8-Lead Plastic MSOP
(LTC DWG # 05-08-1660)
0.118 ± 0.004*
(3.00 ± 0.102)
8
7
6
5
0.118 ± 0.004**
(3.00 ± 0.102)
0.193 ± 0.006
(4.90 ± 0.15)
1
2
3
4
0.040 ± 0.006
(1.02 ± 0.15)
0.034 ± 0.004
(0.86 ± 0.102)
0.007
(0.18)
0° – 6° TYP
SEATING
PLANE
0.012
(0.30)
REF
0.021 ± 0.006
(0.53 ± 0.015)
0.006 ± 0.004
(0.15 ± 0.102)
MSOP (MS8) 1098
0.0256
(0.65)
BSC
* DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH,
PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
14
LTC1729 Series
U
PACKAGE DESCRIPTIO
Dimensions in inches (millimeters) unless otherwise noted.
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.189 – 0.197*
(4.801 – 5.004)
7
5
8
6
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
1
3
4
2
0.010 – 0.020
(0.254 – 0.508)
× 45°
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0.008 – 0.010
(0.203 – 0.254)
0°– 8° TYP
0.016 – 0.050
(0.406 – 1.270)
0.050
(1.270)
BSC
0.014 – 0.019
(0.355 – 0.483)
TYP
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
SO8 1298
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
15
LTC1729 Series
U
TYPICAL APPLICATIO
3A (LT1511) Or 2A (LT1769), 2-Cell Lithium-Ion Battery Charger
D1
SS24
R1
510Ω
INPUT POWER
11.5V TO 28V
GND
SW
CLP
CLN
R
S4
1µF
0.05Ω
TO MAIN
SYSTEM
LOAD
V
CC
D4
SS24
C2
0.47µF
C1*
15µF
R5
3k
LT1511 OR LT1769
D2
SS24
BOOST
L1**
22µH
D3
MBR0540T
UV
R6
COMP1
5.1K
C3
220pF
PROG
V
C
SPIN
C4
0.33µF
C
PROG
1µF
OVP
R
R3
300Ω
SENSE
BAT
PROG
4.93k
R2
1k
R
R
S3
S2
200Ω
R
200Ω
S1
1%
0.05Ω
1%
+
+
C7***
22µF
8.4V
LTC1729-8.4
C6
R7
0.1µF
1.4k
OVP
BAT
SENSE STATUS
GND NTC
V
CC
†
V
C
R4
100Ω
D5
C5
1µF
10k NTC THERMISTOR, NTHS1206N02 VISHAY/DALE
NOTE: EITHER A THERMISTOR OR 10k RESISTOR MUST BE PRESENT
* TOKIN C55Y5U1E156Z
** SUMIDA CDRH125-220MC
*** AVX TPSD226K025R0200
OPTION: TIE RESISTOR TO STATUS FOR
CHARGE TERMINATION AT
LOW CHARGING CURRENT
†
LUMEX SML-LX0805GW-TR
1729 TA04
D1, D2, D4: GENERAL SEMICONDUCTOR
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT1505
High Efficiency Constant-Voltage/Constant-Current
Battery Charger
Uses External Synchronous N-Channel FETs
LT1510
Constant-Voltage/Constant-Current Battery charger
Up to 1.5A Charge Current for Lithium-Ion, NiCd and
NiMH Batteries, Internal R
SENSE
LT1511
LT1512
LT1513
3A Constant-Voltage/Constant-Current Battery Charger
SEPIC Battery Charger
Charges Lithium, NiCd and NiMH Batteries
V
V
Can Be Higher or Lower Than Battery Voltage, 2A Switch
Can Be Higher or Lower Than Battery Voltage, 3A Switch
IN
IN
SEPIC Battery Charger
LT1571-1/LT1571-2 200kHz/500kHz Constant-Current/Constant-Voltage Battery
Up to 1.5A Charge Current for 1- or 2-Cell Li-Ion Batteries,
Preset and Adjustable Battery Voltages, C/10 Charge Detection
LT1571-5
LTC1731
LTC1732
LTC1759
LT1769
Charger Family
Linear Charger
Programmable Timer, C/10 Flag, 8-Pin MSOP
Programmable Timer, C/10 Flag, AC Power Good, 10-Pin MSOP
LT1505 Charger Functionality with SMBus Control
28-Pin SSOP Package
Linear Charger
SMBus-Controlled Smart Battery Charger
2A Constant-Voltage/Constant-Current Battery Charger
1729f LT/LCG 0800 4K • PRINTED IN USA
LINEAR TECHNOLOGY CORPORATION 1999
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
16
●
●
(408)432-1900 FAX:(408)434-0507 www.linear-tech.com
相关型号：
LTC1730-4#TR
IC 1 A BATTERY CHARGE CONTROLLER, PDSO16, SSOP-16, Switching Regulator or Controller
Linear
LTC1730-4.2#TR
IC 1 A BATTERY CHARGE CONTROLLER, PDSO8, SO-8, Switching Regulator or Controller
Linear
LTC1730EGN-4#PBF
LTC1730 - Lithium-Ion Battery Pulse Chargers with Overcurrent Protection; Package: SSOP; Pins: 16; Temperature Range: -40°C to 85°C
Linear
LTC1730ES8-4.2#PBF
LTC1730 - Lithium-Ion Battery Pulse Chargers with Overcurrent Protection; Package: SO; Pins: 8; Temperature Range: -40°C to 85°C
Linear
©2020 ICPDF网 联系我们和版权申明