Datasheet

19
Application Information
Product Overview Description
The ACPL-332J is a highly integrated power control device
that incorporates all the necessary components for a
complete, isolated IGBT / MOSFET gate drive circuit with
fault protection and feedback into one SO-16 package.
Active Miller clamp function eliminates the need of
negative gate drive in most application and allows the
use of simple bootstrap supply for high side driver. An
optically isolated power output stage drives IGBTs with
power ratings of up to 150 A and 1200 V. A high speed
internal optical link minimizes the propagation delays
between the microcontroller and the IGBT while allowing
the two systems to operate at very large common mode
voltage dierences that are common in industrial motor
drives and other power switching applications. An output
IC provides local protection for the IGBT to prevent
damage during over current, and a second optical link
provides a fully isolated fault status feedback signal for
the microcontroller. A built in “watchdog” circuit, UVLO
monitors the power stage supply voltage to prevent IGBT
caused by insucient gate drive voltages. This integrated
IGBT gate driver is designed to increase the performance
and reliability of a motor drive without the cost, size, and
complexity of a discrete design.
Two light emitting diodes and two integrated circuits
housed in the same SO-16 package provide the input
control circuitry, the output power stage, and two optical
channels. The output Detector IC is designed manufac-
tured on a high voltage BiCMOS/Power DMOS process.
The forward optical signal path, as indicated by LED1,
transmits the gate control signal. The return optical signal
path, as indicated by LED2, transmits the fault status
feedback signal.
Under normal operation, the LED1 directly controls the
IGBT gate through the isolated output detector IC, and
LED2 remains o. When an IGBT fault is detected, the
output detector IC immediately begins a “soft” shutdown
sequence, reducing the IGBT current to zero in a con-
trolled manner to avoid potential IGBT damage from
inductive over voltages. Simultaneously, this fault status
is transmitted back to the input via LED2, where the fault
latch disables the gate control input and the active low
fault output alerts the microcontroller.
During power-up, the Under Voltage Lockout (UVLO)
feature prevents the application of insucient gate
voltage to the IGBT, by forcing the ACPL-332J’s output
low. Once the output is in the high state, the DESAT (VCE)
detection feature of the ACPL-332J provides IGBT pro-
tection. Thus, UVLO and DESAT work in conjunction to
provide constant IGBT protection.
Recommended Application Circuit
The ACPL-332J has an LED input gate control, and an
open collector fault output suitable for wired ‘OR’ ap-
plications. The recommended application circuit shown
in Figure 36 illustrates a typical gate drive implementa-
tion using the ACPL-332J. The following describes about
driving IGBT. However, it is also applicable to MOSFET.
Depending upon the MOSFET or IGBT gate threshold re-
quirements, designers may want to adjust the VCC supply
voltage (Recommended V
CC
= 17.5V for IGBT and 12.5V
for MOSFET).
The two supply bypass capacitors (0.1 µF) provide the
large transient currents necessary during a switching
transition. Because of the transient nature of the charging
currents, a low current (5mA) power supply suces. The
desaturation diode D
DESAT
600V/1200V fast recovery type,
t
rr
below 75ns (e.g. ERA34-10) and capacitor C
BLANK
are
necessary external components for the fault detection
circuitry. The gate resistor R
G
serves to limit gate charge
current and controls the IGBT collector voltage rise
and fall times. The open collector fault output has a
passive pull-up resistor R
F
(2.1 kW) and a 330 pF ltering
capacitor, C
F
. A 47 kW pull down resistor R
PULL-DOWN
on
V
OUT
provides a predictable high level output voltage
(V
OH
). In this application, the IGBT gate driver will shut
down when a fault is detected and fault reset by next
cycle of IGBT turn on. Application notes are mentioned at
the end of this datasheet.
Figure 35. Block Diagram of ACPL-332J
SHIELD
SHIELD
D
R
I
V
E
R
V
E
DESAT
V
CC2
V
OUT
V
CLAMP
V
EE
V
CC1
V
S
FAULT
ANODE
CATHODE
V
CLAMP
V
LED
6, 7
5, 8
2
3
1, 4
13
11
14
9, 12
10
16
15
DESAT
UVLO
LED1
LED2
SHIELD
SHIELD
D
R
I
V
E
R
V
E
DESAT
V
CC2
V
OUT
V
CLAMP
V
EE
V
CC1
V
S
FAULT
ANODE
CATHODE
V
CLAMP
V
LED
6, 7
5, 8
2
3
1, 4
13
11
14
9, 12
10
16
15
DESAT
UVLO
LED1
LED2