Broadcom
ACPL-352J-EB1200-RM100
16
ACPL-352J
Reference Manual
Infineon EconoPIM™ 3 IGBT Module EB1200-352J Evaluation Board
Figure 8: Isolated Gate Driver ACPL-352J Primary Side
4.2.2 Gate Driver Circuit: High-Voltage Side
shows the high-voltage side of the gate driver circuitry. It consists of bypass capacitors, an OC protection circuit,
and a driver output stage. The OC protection circuit is described in
Section 4.2.3, Protection Features
. The output stage of
the ACPL-352J is supplied with +15V and –15V. These voltages are supported with 1-µF bypass capacitors that provide
large transient currents that occur during switching transition. The HV blocking diodes, resistor 1 kΩ, and 220-pF blanking
capacitor are used to protect the OC pin and prevent false fault detection. During overcurrent fault conditions, the IGBT is
soft shut down through the SS pin and the rate of shutdown can be adjusted by resistor R25. The gate resistor serves to limit
the gate current and indirectly control the IGBT switching times. Schottky diode D6 is used together with the CLAMP function
to shunt parasitic IGBT Miller current during the off cycle. The status of the IGBT gate voltage is monitored by output pins
VOUTP and VOUTN. The GFAULT output goes low when the gate voltage does not correspond to the LED input logic.
Selection criteria for the gate resistors is described in
Section 4.5, Temperature Measurement
. There are two positions for
VOUTP and two positions for VOUTN on every gate driver where the gate resistor can be placed. This enables the user to
quickly adjust the gate resistor and evaluate switching characteristics of the IGBT. Equivalent turn-on gate resistance is
defined by two parallel resistors (R26 and R27 in
) while the turn-off gate resistance is defined by other two resistors
connected in parallel (R30 and R31). In case of a faulty power supply or unexpected overvoltage, the TVS diode is placed
between the gate and the emitter of the IGBT, and it ensures that no damage is done to the IGBT gate structure. Voltage is
limited to ± 18V.
Figure 9: Isolated Gate Driver ACPL-352J High-Voltage Side
4.2.3 Protection Features
A typical power stage of the three-phase inverter is susceptible to several types of failures, related to the short circuit, which
can potentially cause destruction of the IGBT. To prevent damage to the inverter, fault detection must be implemented to turn
off the IGBTs in case of an overcurrent event. The secondary output stage of the ACPL352J (VOUT, CLAMP, OC, and SS)
is controlled by the combination of VDD2, LED current (IF) and overcurrent (OC) conditions. For the details related to the
logic truth table of these outputs, refer to the ACPL-352J data sheet. The driver provides an ideal solution combining local
overcurrent detection (OC), soft shutdown (SS) with high-speed current output and highp-voltage optical isolation. The OC
part of the gate circuit is marked with a red rectangle in
Summary of Contents for ACPL-352J
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