PI2123 [VICOR]
15 Volt, 15 Amp Full-Function Active ORing Solution; 15伏, 15安培全功能有源或门方案型号: | PI2123 |
厂家: | VICOR CORPORATION |
描述: | 15 Volt, 15 Amp Full-Function Active ORing Solution |
文件: | 总20页 (文件大小:1254K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
PI2123
Cool-ORingTM Series
15 Volt, 15 Amp Full-Function Active ORing Solution
Description
Features
The Cool-ORingTM PI2123 is a complete full-function
•
•
•
Integrated High Performance 15A, 3mΩ
Active ORing solution with a high-speed ORing
MOSFET controller and
MOSFET
a very low on-state
Very-small, high density fully-optimized solution
providing simple PCB layout.
Fast Dynamic Response to Power Source
failures, with 160ns reverse current turn-off
delay time
resistance MOSFET designed for use in redundant
power system architectures. The PI2123 Cool-ORing
solution is offered in an extremely small, thermally
enhanced 5mm x 7mm LGA package and can be
used in high side Active ORing applications on bus
voltages up to 9.6V. The PI2123 enables extremely
low power loss with fast dynamic response to fault
conditions, critical for high availability systems. A
master/slave feature allows the paralleling of PI2123
•
Accurate sensing capability to indicate system
fault conditions
•
•
•
•
•
Programmable under & over-voltage functions
Over temperature fault detection
Adjustable reverse current blanking timer
Master/Slave I/O for paralleling
Active low fault flag output
solutions
for
high
current
Active
ORing
requirements.
The PI2123, with its 3mΩ internal MOSFET provides
very high efficiency and low power loss during
steady state operation, while achieving high-speed
turn-off of the internal MOSFET during input power
source fault conditions that cause reverse current
flow. The PI2123 provides an active low fault flag
output to the system during excessive forward
current, light load, reverse current, over-voltage,
under-voltage and over-temperature fault conditions.
A temperature sensing function indicates a fault if
the maximum junction temperature exceeds 160°C.
The under-voltage and over-voltage thresholds are
programmable via external resistor dividers.
Applications
•
•
•
•
•
N+1 Redundant Power Systems
Servers & High End Computing
Telecom Systems
High-side Active ORing
High current Active ORing ( ≤ 9.6Vbus)
Package Information
•
17-pin 5mm x 7mm Thermally Enhanced LGA
Package
Typical Application:
Figure 2: PI2123 input current de-rating based on maximum
Figure 1: PI2123 High Side Active ORing
TJ=150°C vs. ambient temperature.
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 1 of 20
Pin Description
Pin
Name
Pin
Number
Description
1, 15, 16,
17
D
S
Drain- The Drain of the internal N-channel MOSFET, connect to the output load.
Source-The source of the internal N-channel MOSFET, connect to the input power source
bus voltage.
2, 3, 4, 5
Positive Sense Input & Clamp: Connect SP pin to the S pin. The polarity of the voltage
difference between SP and SN provides an indication of current flow direction through the
MOSFET.
SP
6
Fault State Output: This open collector pin pulls low when a fault occurs. Fault logic inputs
are VC Under-Voltage, Input Under-Voltage, Input Over-Voltage, Forward Over-Current,
light load, reverse current, and Over-Temperature. Leave this pin open if unused.
Blanking timer Input-Output: Connect a resistor from BK to GND to set the blanking time
for the Reverse Comparator function. To configure in slave mode, connect BK to VC. To
configure in master mode with the fastest turn-off response connect BK directly to GND.
Slave Input-Output: This pin is used for paralleling multiple PI2123 solutions in high power
applications. When configured as the Master, this pin functions as an output capable of
7
8
FT
BK
9
SL
driving up to 10
pins of slaved PI2123 devices. It serves as an input when the PI2123 is
SL
configured in slave mode.
Input Supply Pin: This pin is the supply pin for the control circuitry and gate driver.
Connect a 1μF capacitor between VC pin and the GND pin. Voltage on this pin is limited to
15.5V by an internal shunt regulator in high auxiliary voltage applications. For high voltage
auxiliary supply applications connect a shunt resistor between VC and the auxiliary supply.
VC
10
11
GND
Ground: This pin is ground for the gate driver and control circuitry.
Input Over Voltage Input: The OV pin is used to detect an input source over-voltage
condition in ground referenced applications. When the OV pin voltage crosses the OV
OV
12
threshold, the
pin pulls low indicating a fault condition. The input voltage OV threshold
FT
is programmable through an external resistor divider. Connect OV to GND to disable this
function.
Input Under-Voltage Input: The UV pin is used to detect an input source under-voltage
condition in ground referenced applications. When the UV pin voltage drops below the UV
UV
SN
13
14
threshold, the
pin pulls low indicating a fault condition. The input voltage UV threshold
FT
is programmable through an external resistor divider. Connect UV to VC to disable this
function.
Negative Sense Input & Clamp- Connect SN to D pin. The polarity of the voltage
difference between SP and SN provides an indication of current flow direction through the
MOSFET.
Package Pin-out
17 Pin LGA (5mm x 7mm)
Top view
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 2 of 20
Absolute Maximum Ratings
Drain-to-Source Voltage (VDS)
Source Current (IS ) Continuous
Source Current (IS ) Pulsed (10μs)
(3)
15V @ 25°C
15A
60A
54°C/W
Thermal Resistance R
θJA
VC
SN
-0.3V to 17.3V / 40mA
-0.3V to 15V / 10mA
-0.3V to 8.0V / 10mA
-0.3V to 17.3V / 10mA
-0.3V/ 5A peak
SP, OV,
SL
UV,BK,
GND
FT
Storage Temperature
-65oC to 150oC
Operating Junction Temperature
Lead Temperature (Soldering, 20 sec)
-40oC to Over Temperature Fault (TFT)
250oC
ESD Rating
2kV HBM
Electrical Specifications
Unless otherwise specified: -40°C < TJ < 125°C, VC =12V, CVc = 1uF, CSL = 10pF
Parameter
Symbol Min
Typ
Max
Units
Conditions
VC Supply
Operating Supply Range(4)
VVC-GND
IVC
VVC-CLM
RVC
4.5
15
13.2
4.2
V
No VC limiting resistors
Normal Operating Condition, No
Faults
Quiescent Current
3.7
mA
Clamp Voltage
15.5
16
7.5
4.5
V
Ω
IVC=10mA
VC Clamp Shunt Resistance
VC Under-voltage Rising Threshold
VC Under-voltage Falling Threshold
VC Under-voltage Hysteresis
Internal N-Channel MOSFET
Delta IVC=10mA
VVCUVR
VVCUVF
VVCUV-HS
4.3
4.15
150
V
4.0
15
V
mV
In OFF state, ID=250µA ,
Tj=25°C, Figure 10, page 11
Drain-to-Source Breakdown Voltage
Source Current Continuous
Drain Leakage Current
BVDSS
IS
V
A
15
10
In ON state, Tj=25°C
In OFF state, VDS=15V,
Tj=25°C
IDLK
μA
In ON state, IS=10A, Tj=25°C
VC-V(S) ≥ 5V
Drain-to-Source On Resistance
RDSon
Vf-BD
3.0
0.7
4.0
1.0
mΩ
Body Diode Forward Voltage
FAULT
V
In ON state, IS=4A, Tj=25°C
Under-Voltage Rising Threshold
Under-Voltage Falling Threshold
Under-Voltage Threshold Hysteresis
Under-Voltage Bias Current
Over-Voltage Rising Threshold
Over-Voltage Falling Threshold
VUVR
VUVF
VUV-HS
IUV
500
475
25
540
mV
mV
mV
μA
440
-1
1
VOVR
VOVF
500
475
540
mV
mV
440
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 3 of 20
Electrical Specifications
Unless otherwise specified: -40°C < TJ < 125°C, VC =12V, CVc = 1uF, CSL = 10pF
Parameter
Symbol Min
Typ
Max
Units
Conditions
FAULT (Continued)
Over-Voltage Threshold Hysteresis
Over-Voltage Bias Current
Fault Output Low Voltage
VOV-HS
25
mV
μA
V
IOV
VFTL
-1
1
0.2
0.5
10
60
IFT=2mA, VC>3.5V
Fault Output High Leakage Current
Fault Delay Time
IFT-LC
tFT-DEL
TFT
μA
μs
°C
°C
VFT=14V
20
40
160
-10
Includes output glitch filter
Over Temperature Fault (1)
Over Temperature Fault Hysteresis(1)
TFT-HS
DIFFERENTIAL AMPLIFIER AND COMPARATORS
Common Mode Input Voltage
Differential Operating Input Voltage
SP Input Bias Current
VCM
VSP-SN
ISP
-0.1
-50
-50
5.5
V
SP to GND & SN to GND
SP-SN
125
mV
μA
μA
V
-37
3.5
SP=SN=1.25V
SP=SN=1.25V
SP=0V
SN Input Bias Current
ISN
8
10.6
-2
SN Voltage
VSN
Reverse Comparator Threshold
Reverse Comparator Hysteresis
VRVS-TH
VRVS-HS
tRVS-MS
-10
2
-6
mV
mV
VCM = 3.3V
5
VCM = 3.3V
Reverse Fault to Slave Low Delay
Time
Reverse Fault to Slave Low Delay
Time
VSP-SN = -50mV step, VBK=0
(minimum blanking)
VSP-SN = -50mV step, VBK= VVC
(maximum blanking)
160
200
600
ns
ns
tRVS-SL
VFWD-TH
VFWD-HS
VOC-TH
430
6
Forward Comparator Threshold
Forward Comparator Hysteresis
2
9
mV
mV
VCM = 3.3V
VCM = 3.3V
-5
-2
Forward Over Current Comparator
Threshold
Forward Over Current Comparator
Hysteresis
60
-8
66
70
-4
mV
mV
VCM = 3.3V
VCM = 3.3V
VOC-HS
SLAVE
VSL = 1V, Normal Operating
Conditions, No Faults
Normal Operating Conditions,
No Faults
Slave Source Current
ISL
-60
4.3
-25
5.5
μA
Slave Output Voltage High
VSL-Hi
V
Slave Output Voltage Low
Slave Hold-off Voltage at VC UVLO
Slave Threshold
VSL-Lo
VSL-UV
VSL-TH
tSL-FL
0.2
0.7
0.5
1
V
V
ISL=4mA
ISL=5μA,1.5V<VC<3.5V
1.75
15
2
V
Slave Fall Time
Slave Low to FET Turn Off Delay (1)
Time Master Mode
Slave Low to FET Turn Off Delay (1)
25
ns
VBK=0
VBK=0
tG-SL
tG-SL
20
30
ns
ns
100
130
VBK=VC
Time Slave Mode
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 4 of 20
Electrical Specifications
Unless otherwise specified: -40°C < TJ < 125°C, VC =12V, CVc = 1uF, CSL = 10pF
Parameter
Symbol Min
Typ
Max
Units
Conditions
BLANK
Blank Source Current
IBK
VBK
-60
1.2
-45
0.77
1.45
-30
0.9
1.7
μA
V
VBK=0V
IBK=5μA Connected to GND
Blank Output Voltage
Blank Slave Mode Threshold
VBK-TH
V
Note 1: These parameters are not production tested but are guaranteed by design, characterization and
correlation with statistical process control.
Note 2: Current sourced by a pin is reported with a negative sign.
Note 3: Thermal resistance of PI2123 characterized on PI2121-EVAL1 evaluation board with 0 LFM airflow
(PI2121-EVAL1 evaluation board is compatible with the PI2123).
Note 4: Refer to the Auxiliary Power Supply section in the Application Information for details on the VC
requirement to fully enhance the internal MOSFET.
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 5 of 20
Functional Description:
Reverse Comparator: RVS
The PI2123 integrated Cool-ORing product takes
advantage of two different technologies combining a
3mΩ on-state resistance (Rds(on)) single N-channel
MOSFET with high density control circuitry. This
combination provides superior density, minimizing
PCB space to achieve an ideal ORing diode
function, significantly reducing power dissipation and
eliminating the need for heat sinking, while
minimizing design complexity.
The reverse comparator is the most critical
comparator. It looks for negative voltage caused by
reverse current. When the SN pin is 6mV higher
than the SP pin, the reverse comparator will enable
the BK current source to charge an internal 2pF
capacitor. The blanking timer provides noise filtering
for typical switching power conversion that might
cause premature reverse current detection. Once
the voltage across the capacitor reaches the timer
threshold voltage (1.25V) the MOSFET will be
turned off. The shortest blanking time is 50ns when
BK is connected to ground. The Blanking time will
be added to the controller delay time. The Electrical
Specifications in the DIFFERENTIAL AMPLIFIER
AND COMPARATOR section for Reverse Fault to
Slave Low Delay Time “tRVS-MS or tRVS-SL” is the
controller delay time plus the blanking time.
The PI2123’s 3mΩ on-state resistance MOSFET
used in the conduction path enables a dramatic
reduction in power dissipation versus the
performance of a diode used in conventional ORing
applications due to its high forward voltage drop.
This can allow for the elimination of complex heat
sinking
and
other
thermal
management
requirements. Due to the inherent characteristics of
the integrated MOSFET, while the gate remains
enhanced above the gate threshold voltage it will
allow current to flow in the forward and reverse
direction. Ideal ORing applications do not allow for
reverse current flow, so the integrated controller has
to be capable of very fast and accurate detection of
reverse current caused by input power source
failures, and turn off the gate of the MOSFET as
quickly as possible. Once the gate voltage falls
below the gate threshold, the MOSFET is off and the
body diode will be reverse biased preventing reverse
current flow and subsequent excessive voltage
droop on the redundant bus. During forward over-
current conditions caused by load faults, the
controller maintains gate drive to the MOSFET to
keep power dissipation as low as possible,
otherwise the inherent body diode of the MOSFET
would conduct, which has higher effective forward
drop. Conventional ORing solutions using diodes
offer no protection against forward over-current
conditions. During the forward over-current
condition, the PI2123 will provide an active-low fault
flag to the system via the fault pin. The fault flag is
also issued during the reverse current condition,
light load conditions, VC under-voltage, Input Under-
Voltage and Over-Voltage and Over-Temperature
conditions.
Reverse Blanking Timer: BK
Connecting an external resistor ( BK ) between the
R
BK pin and ground will increase the blanking time as
shown in the following chart.
Where:
RBK ≤ 200KΩ
If BK is connected to VC for slave mode operation,
then the blanking time will be about 320ns typically,
and total delay time will be 430ns.
The reverse comparator has 3mV of hysteresis
referenced to SP-SN.
If the conditions are met for a reverse current fault,
then the active-low fault flag output will also indicate
a fault to the system after the 40µs fault delay
time.
Differential Amplifier:
The PI2123 integrates a high-speed, low offset
voltage differential amplifier to sense the difference
between the Sense Positive (SP) pin voltage and
Sense Negative (SN) pin voltage with high accuracy.
The amplifier output is connected to three
comparators:
Reverse
comparator,
Forward
comparator, and Forward over-current comparator.
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 6 of 20
Forward Voltage Comparator: FWD
condition when VC is lower than the VC Under-
Voltage Threshold
The FWD comparator detects when a forward
current condition exists and SP is 6mV positive with
respect to SN. When SP-SN is less than 6mV, the
FWD comparator will assert the Fault flag to report a
fault condition indicative of a light load or “load not
present” condition or possible shorted MOSFET.
UV:
The Under-Voltage (UV) input trip point can be
programmed through an external resistor divider to
monitor the input voltage. The UV comparator
initiates a fault condition and pulls the
pin low,
FT
Forward Over Current Comparator: FOC
when UV falls below the Under-Voltage Falling
Threshold. If the PI2123 is configured in a floating
application, where the GND pin is connected to the
input voltage, the UV pin cannot detect the input
voltage. In this case, the UV pin should be disabled
by connecting it to the VC pin.
The FOC comparator indicates an excessive forward
current condition when SP is 66mV (typical) higher
than SN. When the FET is in the on-state and SP-
SN is higher than 66mV (typical) the PI2123 will
initiate a fault condition via the
pin.
FT
OV:
Slave:
The Over-Voltage (OV) input trip point can be
programmed through an external resistor divider to
monitor the input voltage. The OV comparator
In high current applications that exceed the single
PI2123 current handling capability, multiple PI2123’s
can be paralleled and synchronized by using the
slave function.
initiates a fault condition and pulls the
pin low
FT
when OV rises above the Over-Voltage Rising
Threshold. If the PI2123 is configured in a floating
application, where the GND pin is connected to the
input voltage, the OV pin cannot detect the input
voltage. In this case, the OV pin should be disabled
by connecting it to the control GND pin.
The Slave function synchronizes multiple PI2123’s
together and allows for localized control of each
paralleled MOSFET. One PI2123 will be designated
as the master and it will control the response of the
slaved PI2123’s.
When the PI2123 is configured in the “Master Mode”
Over-Temperature Detection:
The internal Over-Temperature block monitors the
junction temperature of the controller. The over-
temperature threshold is set to 160°C with -10°C of
by connecting the BK to ground, the
output having the same signal characteristics as the
internal Gate Driver. In this configuration, the
will be an
SL
hysteresis.
When the controller temperature
output is capable of driving up to ten PI2123’s,
SL
configured in “Slave Mode”, through their
corresponding pins. Logic high for the pin is
exceeds this threshold, the over-temperature circuit
initiates a fault condition and pulls the
pin low.
FT
SL
limited to 5.5V (max).
SL
Fault:
The fault circuit output is an open collector with 40μs
When the BK pin is tied to VC, the PI2123 becomes
a slave and the pin will be an input. The internal
Gate driver section and reverse current section are
the only active circuits in the slaved PI2123 while the
master performs the diagnostics and gate drive
control.
delay to prevent any false triggering. The pin
FT
SL
will be pulled low when any of the following faults
occur:
•
•
•
•
•
•
•
Reverse Current
Forward Over-Current
Forward Low Current
Over-Temperature
Input Under-Voltage
Input Over-Voltage
VC pin Under-Voltage
VC and Internal Voltage Regulator:
The PI2123 has a separate input (VC) to provides
power to the controller circuitry and the internal gate
driver. An internal regulator clamps the VC voltage
to 15.5V.
A gate voltage detector prevents FOC or FWD from
initiating a fault when the MOSFET is in an OFF
condition.
For high side applications, the VC input should be at
least 6V above the bus voltage (Vin) to properly
enhance the internal N-channel MOSFET.
The only fault condition that initiates gate turn-off of
the MOSFET (as well as a fault flag signal) is when
the reverse current fault conditions are met. All other
fault conditions issue only a fault flag signal via the
The internal regulator circuit has a comparator to
monitor the VC voltage and initiates a FAULT
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 7 of 20
reported to a Host to signal that some system level
maintenance may be required.
pin, but do not affect the gate of the MOSFET.
FT
The
pin serves as an indicator that a fault
FT
condition may be present. This information can be
Figure 3: PI2123 Internal Block Diagram
Figure 4: Comparator hysteresis, values are for reference only, please refer to the electrical specifications
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 8 of 20
Figure 5: Timing diagram for two PI2123 solutions in an Active ORing application
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 9 of 20
Figure 6: PI2123 State diagram, Master Mode
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 10 of 20
Typical Characteristics:
Figure 8: Reverse comparator threshold vs. temperature.
VCM: Common Mode Voltage.
Figure 7: Reverse Condition internal MOSFET Turn off
delay time vs. temperature.
Figure 9: Controller bias current vs. temperature.
Figure 10: Internal MOSFET Drain to source breakdown
voltage vs. temperature.
Figure 12: Internal MOSFET source to drain diode
forward voltage (pulsed ≤300µs).
Figure 11: Internal MOSFET on-state resistance vs.
temperature.
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 11 of 20
Thermal Characteristics:
Figure 13: Junction Temperature vs. Input Current
Figure 14: Junction Temperature vs. Input Current
(0LFM)
(200LFM)
Figure 16: PI2123 mounted on PI2121-EVAL1
Thermal Image picture, Iout=15A, TA=25°C,
Air Flow=200LFM
Figure 15: PI2123 mounted on PI2121-EVAL1
Thermal Image picture, Iout=15A, TA=25°C,
Air Flow=0LFM
Figure 17: PI2123 input current de-rating based on maximum TJ=150°C vs. ambient temperature
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 12 of 20
Figure 18: Plot of PI2123 response time to reverse current detection
Application Information
The PI2123 is designed to replace ORing diodes in
high current, low voltage redundant power
architectures. Replacing a traditional diode with a
PI2123 will result in significant power dissipation
reduction as well as board space reduction,
efficiency improvement and additional protection
comparator response time of 160ns typical. To
increase the blanking time, connect the BK pin to
GND via a resistor to avoid the fault response to
short reverse current pulses. Refer to the plot in the
reverse comparator functional description for
resistor values versus the reverse blanking time.
features.
This section describes in detail the
procedure to follow when designing with the PI2123
Active ORing solution.
Auxiliary Power Supply (Vaux):
Vaux is an independent power source required to
supply power to the VC input. The Vaux voltage
should be 6V higher than Vin (redundant power
source output voltage) to fully enhance the internal
MOSFET.
A bias resistor (Rbias) is required if Vaux is higher
than 15V. Rbias should be connected between the
VC pin and Vaux.
Fault Indication:
The
output pin is an open collector and should
FT
be pulled up to the logic voltage or to the controller
VC via a resistor (10KΩ)
Blanking Timer:
Connect the blanking timer pin (BK) to GND to
program the device for the fastest reverse
Minimize the resistor value for low Vaux voltage
levels to avoid a voltage drop that may reduce the
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 13 of 20
VC voltage lower than required to drive the gate of
the internal MOSFET.
reduce the magnitude of the ringing voltage, add a
ceramic capacitor very close to the source that can
react to the voltage ringing frequency and another
capacitor close to the drain. Recommended values
for the ceramic capacitors are 1µF, refer to C5 and
C7 in Figure 23.
Select the value of Rbias using the following
equations:
Vauxmin −VCclamp
Rbias =
ICmax
Slave:
Rbias maximum power dissipation:
For a high current application where one PI2123 can
not handle the total load current, multiple PI2123’s
can be paralleled in a master/slave configuration to
2
(Vauxmax −VCclamp
)
PdRbias
=
Rbias
support the total current per input.
In the
Where:
Master/Slave mode, one PI2123 is configured as the
master and the rest are configured as slaves. The
Vauxmin : Vaux minimum voltage
Vauxmax : Vaux maximum voltage
VCClamp : Controller clamp voltage, 15.5V
slave ( ) pin of the master unit will act as an
SL
output driving the units configured in slave mode.
The
pins of the slave units will act as inputs
SL
ICmax : Controller maximum bias current, use
under the control of the master.
4.2mA
Tie the BK pin to VC to configure the unit in slave
mode.
Example: Vaux 20V to 30V
Power dissipation:
Vauxmin −VCclamp
20V −15.5V
4.2mA
In active ORing circuits the MOSFET is always on in
steady state operation and the power dissipation is
derived from the total source current and the on-
state resistance of the internal MOSFET.
Rbias =
=
=1.07KΩ
ICmax
2
(30V −15.5V)2
(Vauxmax −VCclamp
)
PdRbias
=
=
=196mW
Rbias
1.07KΩ
The PI2123 internal MOSFET power dissipation can
be calculated with the following equation:
Internal N-Channel MOSFET BVdss:
The PI2123’s internal N-Channel MOSFET
breakdown voltage (BVdss) is rated for 15V at 25°C
and will degrade at -40°C to 14.4V, refer to Figure
10. In an application when the MOSFET is turned
off due to a reverse fault, the series parasitic
elements in the circuit may contribute to the
MOSFET being exposed to a voltage higher than its
voltage rating.
PdMOSFET = Is2 ∗Rds(on)
Where:
Is
: Source Current
Rds(on) : MOSFET on-state resistance
Note:
Calculate with Rds(on) at maximum MOSFET
temperature because Rds(on) is
temperature
dependent, Refer to figure 11 for normalized
Rds(on) values over temperature. PI2123 nominal
Rds(on) at 25°C is 3mΩ and will increase by ~40%
at 125°C junction temperature.
In Active ORing applications when one of the input
power sources is shorted, a large reverse current is
sourced from the circuit output through the
MOSFET. Depending on the output impedance of
the system, the reverse current may reach over 60A
in some conditions before the MOSFET is turned off.
Such high current conditions will store energy even
in a small parasitic element. For example: a 1nH
parasitic inductance with 60A reverse current will
generate 1.8µJ (½Li2). When the MOSFET is turned
off, the stored energy will be released and produce a
high negative voltage ringing at the MOSFET
source. At the same time the energy stored at the
drain side of the internal MOSFET will be released
and produce a voltage higher than the load voltage.
This event will create a high voltage difference
between the drain and source of the MOSFET. To
The Junction Temperature rise is a function of power
dissipation and thermal resistance.
Trise= Rth ∗PdMOSFET = Rth ∗Is2 ∗Rds(on),
JA
JA
Where:
RthJA : Junction-to-Ambient thermal resistance
(54°C/Watt)(3)
This may require iteration to get to the final junction
temperature. Figures 13, 14 and 17 show the
PI2123 internal MOSFET final junction temperature
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 14 of 20
curves versus conducted current at given ambient
temperatures and air flow.
Where:
V(UVTH )
: UV threshold voltage at Vin.
: OV threshold voltage at Vin.
: UV voltage set
V(OVTH )
V (UV )
IRa
OV/UV resistor selection:
The UV and OV comparator inputs are used to
monitor the input voltage and will indicate a fault
condition when this voltage is out of range. The UV
& OV pins can be configured in two different ways,
either with a divider on each pin, or with a three-
resistor divider to the same node, enabling the
elimination of one resistor. Under-voltage is
monitored by the UV pin input and over-voltage is
monitored with the OV pin input.
:
current.
Ra
Alternatively,
a
two-resistor voltage divider
configuration can be used and is shown in Figure
20.
The Fault pin (
) will indicate a fault (active low)
FT
when the UV pin is below the threshold or when the
OV pin is above the threshold. The threshold is
0.50V typical with 25mV hysteresis and the input
current is less than ±1µA. It is important to consider
the maximum current that will flow in the resistor
divider and maximum error due to UV and OV input
current. Set the resistor current to 100µA or higher
to maintain better than 1% accuracy for UV and OV
due to the bias current.
Figure 20: UV & OV two-resistor divider
configuration
The UV resistor voltage divider can be obtained from
the following equations:
V (UVTH )
The three-resistor voltage divider configuration for
both UV and OV to monitor the same voltage node
is shown in Figure 19:
R1UV
=
IRUV
Set R1UV value based on system allowable current
IRUV ≥100μA
⎛
⎞
V (UV )
⎜
⎜
⎟
⎟
R2UV = R1UV
−1
V (UVTH )
⎝
⎠
Where:
: UV threshold voltage
V (UVTH )
:
current
R1UV
IRUV
Figure 19: UV & OV three-resistor divider
V (UVTH )
configuration
R1UV
=
IRUV
V (OVTH )
Ra =
Set R1OV value based on system allowable current
IRUV ≥100μA
IRa
Set Ra value based on system allowable current
IRa
⎛
⎞
V (OV )
V (OVTH
⎜
⎜
⎟
⎟
R2OV = R1OV
−1
⎛
⎞
V (OV )
V (UV )
)
⎝
⎠
⎜
⎜
⎟
⎟
Rb = Ra
−1
Where:
V (OVTH
⎝
⎠
: OV threshold voltage
)
⎛
⎜
⎞
V (UV )
:
current.
R1OV
IROV
⎟
⎟
Rc =
(
Ra + Rb
)
−1
⎜
V (UVTH )
⎝
⎠
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 15 of 20
Typical Application Example 1:
Requirement:
Redundant Bus Voltage = 5.0V
Load Current = 12A (assume through each
redundant path)
Maximum Ambient Temperature = 75°C: no air flow.
Auxiliary Voltage = 12V (10V to 14V)
Solution:
A single PI2123 for each redundant 5.0V power
source should be used, configured as shown in the
circuit schematic in Figure 22.
Vaux: Since the Vaux voltage does not exceed the
VC pin clamp voltage, connect the Vaux directly to
the VC pin
SP and SN pins: Connect each SP pin to the S pins
and each SN pin to the D pins
Figure 21: Example 1 final junction temperature at
12A/75°C TA
BK pin: Connect the BK pin to the ground to
achieve the minimum reverse current response time.
maximum at 117°C
Rds(on) = 4.0mΩ•1.35= 5.4mΩ
SL pin: Not required, so leave floating
Rth : 54°C/W
JA
T =TA + Rth ∗Is2 ∗Rds(on)
pin: Connect to the logic input and to the logic
power supply via a 10KΩ resistor.
FT
J
JA
Recalculate TJ:
Program UV and OV to monitor input voltage:
Program UV at 4.5V and OV at 5.5V
Use the three-resistor divider configuration:
54°C
⎛
⎞
T = 75°C +
∗(12A)2 ∗5.4mΩ =116.99°C
⎜
⎟
⎠
J
W
⎝
Maximum power dissipation at 117°C Junction
Temperature:
IRa = 200μA
500mV
Pdmax = Iin2 ∗Rds(on) = (12A)2 ∗5.4mΩ = 777mW
or 2.49kΩ 1%
Ra =
= 2.5kΩ
5.5V
200μA
⎛
⎜
⎞
⎠
Reverse current threshold is:
or 549Ω 1%
Rb = 2.49kΩ
−1 = 553Ω
⎟
The following procedure demonstrates how to
calculate the minimum required reverse current in
the internal MOSFET to generate a reverse fault
condition and turn off the internal MOSFET.
4.5V
⎝
4.5V
⎛
⎝
⎞
⎠
1%
Rc =
(
2.49kΩ + 549Ω
)
−1 = 24.3kΩ
⎜
⎟
500mV
Power Dissipation and Junction Temperature:
First use Figure 13 (Junction Temperature vs. Input
Current) to find the final junction temperature at 12A
load current and 75°C ambient temperature. In
Figure 13 (illustrated in Figure 21) draw a vertical
line from 12A to half way between the TA=70°C and
TA=80°C lines. Then draw a horizontal line towards
the Y-axis (Junction Temperature). The Junction
Temperature at full load current (12A) and 75°C
ambient is 117°C.
At room temperature (25°C) typical Rds(on):
Vth.reverse − 6mV
Is.reverse =
=
= −2.0A
Rds(on)
3.0mΩ
At maximum junction temperature (117°C) and
maximum Rds(on):
Vth.reverse − 6mV
Is.reverse =
=
= −1.11A
Rds(on)
5.4mΩ
Rds(on) is 4.0mΩ maximum at 25°C and will
increase as the Junction temperature increases.
From Figure 11, at 117°C Rds(on) will increase by
~35%, then
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 16 of 20
Figure 22: Two PI2123 in High Side ORing configuration
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 17 of 20
Layout Recommendation:
Use the following general guidelines when designing
printed circuit boards. An example of the typical
land pattern for the PI2123 is shown in Figure 23:
will produce a high voltage across the MOSFET.
If it is not possible to connect the power source
and S pins with a very short trace or common
point, connect a capacitor (shown as C5 in
figure 23), recommended value 1µF, close to the
S pins and return (ground). Also for the same
reason use C7 in figure 23 at the output.
•
Make sure to have a solid ground (return) plane
to reduce circuit parasitic.
•
Connect all S pads together with a wide trace to
reduce trace parasitics to accommodate the high
current input, and also connect all D pads
together with a wide trace to accommodate the
high current output.
•
•
Connect the SP pin to the S pins and connect
the SN pin to D pins as shown in figure 23.
Use 1oz of copper or thicker if possible to
reduce trace resistance and reduce power
dissipation.
•
The VC bypass capacitor should be located as
close as possible to the VC and GND pins.
Place the PI2123 and bypass capacitor on the
same layer of the board. The VC pin and CVC
(shown as C2 in Figure 23) PCB trace should
not contain any vias or connect to the ground
plane close to GND pin.
•
Keep the power source very close to the S input
pins, any parasitic in the trace connecting the
power source and S pins will have inductive kick
back when there is high current flow in the trace
and the MOSFET turns off due to reverse
current fault conditions. The inductive kick back
Figure 23: PI2123 layout recommendation
Figure 24: PI2123 Mounted on PI2121-EVAL1
Please visit www.picorpower.com for information on PI2121-EVAL1
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 18 of 20
Package Drawing
Thermal Resistance Ratings
Parameter
Symbol
θJA
Typical
Max
-
Unit
°C/W
°C/W
Junction-to-Ambient (3)
54
Junction-to-PCB
14
-
θJC
Note 3: Thermal resistance characterized on PI2125-EVAL2 evaluation board with 0 LFM airflow.
Ordering Information
Part Number
Package
Transport Media
PI2123-00-LGIZ
5x7mm 17-pin LGA
Tape & Reel
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 19 of 20
Warranty
Vicor products are guaranteed for two years from date of shipment against defects in material or workmanship
when in normal use and service. This warranty does not extend to products subjected to misuse, accident, or
improper application or maintenance. Vicor shall not be liable for collateral or consequential damage. This
warranty is extended to the original purchaser only.
EXCEPT FOR THE FOREGOING EXPRESS WARRANTY, VICOR MAKES NO WARRANTY, EXPRESS OR
LIMITED, INCLUDING, BUT NOT LIMITED TO, THE WARRANTY OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE.
Vicor will repair or replace defective products in accordance with its own best judgment. For service under this
warranty, the buyer must contact Vicor to obtain a Return Material Authorization (RMA) number and shipping
instructions. Products returned without prior authorization will be returned to the buyer. The buyer will pay all
charges incurred in returning the product to the factory. Vicor will pay all reshipment charges if the product was
defective within the terms of this warranty.
Information published by Vicor has been carefully checked and is believed to be accurate; however, no
responsibility is assumed for inaccuracies. Vicor reserves the right to make changes to any products without
further notice to improve reliability, function, or design. Vicor does not assume any liability arising out of the
application or use of any product or circuit; neither does it convey any license under its patent rights nor the rights
of others. Vicor general policy does not recommend the use of its components in life support applications wherein
a failure or malfunction may directly threaten life or injury. Per Vicor Terms and Conditions of Sale, the user of
Vicor components in life support applications assumes all risks of such use and indemnifies Vicor against all
damages.
Vicor’s comprehensive line of power solutions includes high density AC-DC and DC-DC
modules and accessory components, fully configurable AC-DC and DC-DC power
supplies, and complete custom power systems.
Information furnished by Vicor is believed to be accurate and reliable. However, no responsibility is assumed by
Vicor for its use. Vicor components are not designed to be used in applications, such as life support systems,
wherein a failure or malfunction could result in injury or death. All sales are subject to Vicor’s Terms and
Conditions of Sale, which are available upon request.
Specifications are subject to change without notice.
Vicor Corporation
25 Frontage Road
Andover, MA 01810
USA
Picor Corporation
51 Industrial Drive
North Smithfield, RI 02896
USA
Customer Service: custserv@vicorpower.com
Technical Support: apps@vicorpower.com
Tel: 800-735-6200
Fax: 978-475-6715
Picor Corporation • picorpower.com
PI2123
Rev 1.0 Page 20 of 20
相关型号:
©2020 ICPDF网 联系我们和版权申明