Broadcom ACPL-C87AT, ACPL-32JT User Manual
ACPL-32JT, ACPL-C87AT
Evaluation Driver Board for Fuji M652 6-in-1 IGBT
User Guide
Introduction
This evaluation driver board is optimized for a Fuji M652 6-in-1
Integrated Gate Bipolar Transistor (IGBT ) module rated at 650V,
600A. It features 6 x ACPL-32JT for IGBT gate driving and 1 x
ACPL-C87AT for bus voltage sensing.
Figure 1 Evaluation Driver Board for Fuji M652 IGBT
An ACPL-32JT monitors each IGBT for short circuit events by
way of the collector voltage and triggers a local fault shutdown
sequence when required. A small gate discharge device slowly
reduces the short circuit collector current to prevent
overvoltage damage. The IGBT is shut off before the dissipated
energy can reach destructive levels.
Key Features
Gate Driver
The ACPL-32JT is an Automotive 2.5 Amp Gate Drive
Optocoupler. It features an integrated flyback controller for
isolated DC-DC converter, IGBT desaturation sensing, and
protection with soft-shutdown.
Integrated Flyback Controller
Each ACPL-32JT has an integrated DC-DC flyback controller
that is paired with a flyback transformer to provide a split rail
Vcc2 voltage of +15V/–5V with up to 2W of isolated power for
driving each IGBT. This distributed power supply architecture
removes the need for a separate monolithic power supply.
Bus Voltage Sensing
The ACPL-C87AT is an automotive unity-gain isolated voltage
sensor that utilizes superior optical coupling technology, with a
sigma-delta analog-to-digital converter, chopper stabilized
amplifiers, and a fully differential circuit topology to provide
unequaled isolation-mode noise rejection, low offset, high gain
accuracy, and stability.
An ACPL-C87AT is used with a resistor chain for bus voltage
sensing.
Fault Detection and Protection
The power stage of a typical three-phase inverter is susceptible
to destructive failures due to overcurrent and overvoltage
conditions.
Broadcom
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ACPL-32JT, ACPL-C87AT User Guide
Board Operation
Power Supply
The board accepts 8V to 18V applied across DC12 to GND1. The
nominal voltage is 12V.
PWM Inputs
There are six Pulse Width Modulation (PWM) inputs for driving
the IGBT module: PWMLW, PWMHW, PWMLV, PWMHV, PWMLU,
PWMHU.
0V: Input Low
5V: Input High (max 5.5V)
Signals are referenced to GND1.
The input LEDs of the ACPL-32JT gate drivers are driven by an
on-board current buffer.
Desat Fault Feedback
There are six Desat Fault feedback outputs, one for each IGBT:
FLU, FHU, FLV, FHV, FLW, FHW.
When fault on gate driver secondary side is detected, Fault
feedback is pulled Low.
Low: Desat Fault Detected
High (5V): No Fault
Board Design
Gate Driving
Figure 2 Gate Driving
The Gate Driver output is connected to a push-pull buffer to
drive the IGBT gate.
The strength of the turn-on and turn-off is controlled by Ron
and Roff respectively (R23 and R24 in Figure 2).
UVLO Feedback
There are six Under-Voltage Lock Out (UVLO) feedback outputs,
one for each IGBT: ULU, UHU, ULV, UHV, ULW, UHW.
When undervoltage on gate driver secondary side is detected,
UVLO feedback is pulled Low.
Low: Undervoltage Detected
High (5V): Voltage Normal
Broadcom
Soft Shutdown
Figure 3 Soft Shutdown
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ACPL-32JT, ACPL-C87AT User Guide
The IGBT collector voltage is sensed by the ACPL-32JT gate
drivers through the Desat pin. When desaturation events are
detected, ACPL-32JT applies a soft shutdown to the IGBT gate
to prevent damage. A PNP buffer transistor is used to
customize the shutdown process. The shutdown strength is
controlled by Rssd and Cssd.
Desat Blanking
Figure 4 Desat Blanking
The total blanking time is calculated in terms of internal
blanking time tDESAT(BLANKING) (0.6 μs typ), external
capacitance CBLANK (330 pF), FAULT threshold voltage VDESAT
(7V typ), and DESAT charge current ICHG (0.9 mA typ) as
follows:
tBLANK = tDESAT(BLANKING) + (CBLANK × VDESAT/ICHG)
= 0.6 μs + (330 pF × 7V/0.9 mA)
~ 3.2 μs
Active Clamp
Figure 5 Active Clamp
A Transient Voltage Suppressor (TVS) rated at 510V is placed
between the Gate and Collector of the IGBT to provide active
clamp protection. Vce of the IGBT is clamped and protected by
the TVS.
DC/DC Converter
Figure 6 DC/DC Converter
Each ACPL-32JT Gate Driver integrates a DC/DC converter that
provides distributed power to the secondary side.
For DC12 = 8V to 18V, this circuit nominally supports a
secondary-side load of up to 60 mA (including Icc2 of
ACPL-32JT) at the regulated VCC2 voltage.
Figure 7 Compensation Network
The compensation network is referenced to a nominal
transformer of Lp = 60 μH, Ls = 260 μH.
Broadcom
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ACPL-32JT, ACPL-C87AT User Guide
Bus Voltage Sense Ratio
R146 R147+
R142 R143 R144 R145 R146 R147+++++
----------------------------------------------------------------------------------------------------------
=
2k 2k+
200k 200k 200k 200k 2k 2k+++++
-------------------------------------------------------------------------------------------
=
4.975 mV/V =
Bus Voltage Sensing
Bus voltage is sensed through a precision resistor chain. ACPL-C87AT optically isolates the signal for transmission to a
microcontroller (output Voltage Sense Output (VSO) on P1 header).
The Bus Voltage Sense Ratio may be calculated as follows:
Connection Interface (Connector Header P1)
Pin Name Typ e LEVEL Item Logic
1 FLU OUT TTL Fault Feedback for U-bottom L: Fault
3 ULU OUT TTL Under-Voltage Lock Out Feedback for
5 FLV OUT TTL Fault Feedback for V-bottom L: Fault
7 ULV OUT TTL Under-Voltage Lock Out Feedback for
9 FLW OUT TTL Fault Feedback for W-bottom L: Fault
11 ULW OUT TTL Under-Voltage Lock Out Feedback for
13 UHU OUT TTL Under-Voltage Lock Out Feedback for U-top L: Under-Voltage Lock Out
15 FHU OUT TTL Fault Feedback for U-top L: Fault
17 UHV OUT TTL Under-Voltage Lock Out Feedback for V-top L: Under-Voltage Lock Out
19 FHV OUT TTL Fault Feedback for V-top L: Fault
21 UHW OUT TTL Under-Voltage Lock Out Feedback for W-top L: Under-Voltage Lock Out
23 FHW OUT TTL Fault Feedback for W-top L: Fault
2 PWMLW IN TTL PWM input for W-bottom H: Led on, L: Led off
4 PWMHW IN TTL PWM input for W-top H: Led on, L: Led off
6 PWMLV IN TTL PWM input for V-bottom H: Led on, L: Led off
8 PWMHV IN TTL PWM input for V-top H: Led on, L: Led off
10 PWMLU IN TTL PWM input for U-bottom H: Led on, L: Led off
12 PWMHU IN TTL PWM input for U-top H: Led on, L: Led off
14 DC12 Power 8V to 18V DC power supply —
16 GND1 Ground Ground Low Voltage Side Ground —
18 GND1 Ground Ground Low Voltage Side Ground —
20 VSO OUT Analog
(0 to 2V)
22 OT1 OUT — Connection to IGBT NTC Thermistor Pin T1 —
24 OT2 OUT — Connection to IGBT NTC Thermistor Pin T2 —
U-bottom
V-bottom
W-bottom
Bus Voltage Sensor Output Analog (0 to 2V)
L: Under-Voltage Lock Out
L: Under-Voltage Lock Out
L: Under-Voltage Lock Out
Broadcom
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ACPL-32JT, ACPL-C87AT User Guide
Circuit Schematic
M652 Driver Board
GND1
GND1
GND1
GND1
GND1
GND1
GND1
GND1
GND1
GND1
GND1
GND1
DC5
C36 1nF
DC5
C37 1nF
DC5
C76 1nF
DC5
C77 1nF
DC5
C116 1nF
DC5
C117 1nF
C16 1nF
DC5
C17 1nF
DC5
C56 1nF
DC5
C57 1nF
DC5
C96 1nF
DC5
C97 1nF
R34 4K7
R33 4K7
R74 4K7
R73 4K7
R114 4K7
R113 4K7
4K7
4K7
R14
R53 4K7
R54 4K7
R93 4K7
R94 4K7
P1
FLU
1 2
ULU
3 4
FLV
5 6
ULV
7 8
FLW
9 10
ULW
11 12
UHU
13
FHU
15
UHV
17
FHV
19
UHW OT1
21
FHW OT2
23
DF11CZ24DS2V22
PWMLW
PWMHW
PWMLV
14
16
18
20
22
24
PWMHV
PWMLU
PWMHU
DC12
GND1
GND1
VSO
GND1
C11
10uF
1
GND1
Q161
2
FCX591A
3
R161
1K
1
D66
MMSZ4689ET1G
2
U11
NCV8664ST50T3G
0.1uF
1
VIN
OUT
GND
2
GND1GND1
VCC1DC12DC5 R13
C131
DC5
3
C132
10uF
GND1
GND1
GND1
GND1
R162
5K
R163
5K
R164
5K
PWMHU
PWMALU
PWMHV
PWMAHV
GND1
1
2
3
4
5
6
7
Broadcom
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U12
1A
1Y
2A
2Y
3A
3Y
GND
SN74AC04-Q1
VCC
DC5
14
PWMLVPWMAHU
13
6A
PWMALVPWMLU
12
6Y
11
PWMLW
5A
10
PWMALW
5Y
9
PWMHW
4A
8
PWMAHW
4Y
C161
0.1uF
5K
R165
R166 5K
R167 5K
GND1
GND1
GND1
GND1
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