Avago Technologies

- 21 -

ACPL-352J

Data Sheet

Applications Information

Description of Gate Driver and Miller Clamping

The gate driver is directly controlled by the LED current. When LED current is driven high the output of ACPL-352J is capable of

delivering 5A maximum sourcing current to drive the IGBT's/MOSFET's gate. While LED is switched off the gate driver can provide

5A maximum sinking current to switch the gate off fast. Additional miller clamping pull-down transistor is activated when output

Figure 22 Gate Drive Signal Behavior

Description of Under Voltage Lock Out

Insufficient gate voltage to IGBT/MOSFET can increase turn on resistance of IGBT/MOSFET, resulting a large power loss and

power supply is lower than under voltage lockout (UVLO) threshold gate driver output will shut off to protect IGBT/MOSFET from

low voltage bias. During power up, the UVLO feature locks the gate driver output low to prevent unwanted turn on at lower supply

voltage.

Figure 23 Circuit Behaviors at Power Up and Power Down

Miller Clamp turns on at

Miller Clamp

HI-Z

HI-Z

UVLO

Miller Clamp

Miller Clamp

HI-Z

HI-Z