STGAP1AS datasheet(31/70 Pages) STMICROELECTRONICS

31 / 70 page

DocID029344 Rev 2

31/70

STGAP1AS

Functional description

Figure 11. DESAT protection timing diagram

A deglitch filter is applied to the DESAT pin. Each pulse exceeding the VDESATth for a time

shorter than tDESfilter value shall not trigger the protection.

7.7

VCE active clamping protection

This protection is used to actively clamp the drain/collector overvoltage spikes during the

MOSFET/IGBT turn-off. This feature allows using low turn-off resistor values leading lower

turn-off losses, thus increasing efficiency, while limiting the maximum turn-off spike on the

collector (or drain) within safe limits.

The direct feedback of the collector voltage to the device can for example be made via an

element with avalanche characteristics such as a TVS. If the VCE voltage exceeds the

breakdown voltage of the TVS, the VVCECLth threshold voltage on the VCECLAMP is

reached and the IC actively slows down the power switch turn-off to keep a safe condition.

The active limiting of the driver's turn-off current strongly reduces the current flowing

through the TVS, thus preventing it from operating in overstressing conditions.

DESAT

VH level

DiagX

VL level

Blanking time

Comparator Disabled

Comparator Enabled

tBLK

tDESAT

IN+

VDESATth

GON-GOFF

tDIAGx

STGAP1AS Datasheet(PDF) 31 Page - STMicroelectronics