STDRIVE102H datasheet(29/56 Pages) STMICROELECTRONICS

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Figure 20. VDS monitoring basic diagram

VCC

BOOT

GHSx

OUTx

GLSx

SLSx

VDS,th

VDSTH

VDS,th

VDS,HS

VDS,LS

The VDS monitoring protection can detect different failures related to the power stage:

•

Gate open. The gate connection is missing, or the gate is damaged.

•

Gate short. The gate is damaged and there is a short between the gate and source.

•

OUT short. The OUT pin can be shorted to another motor phase, to GND or to VM.

In all these cases, the MOSFET does not turn on and its VDS does not fall below the expected threshold (set on

the VDSTH pin).

In other cases, the MOSFETs turn on and work correctly, but unexpected behavior can be detected as well by the

VDS monitoring.

•

Overload. In the case of current overload on the motor, the VDS on the MOSFET can increase and become

higher than the threshold. Moreover, the temperature increase due to higher current can also lead to an

increase of the RDS,on of the MOSFET and thus a further increase of the VDS measured.

•

TCC/IGATE configuration: if the driver current IGATE,on or the time tcc,on are too small, the external

MOSFET turns on too slowly or with higher RDS,on and its VDS could not fall below the expected VDS,th

threshold within the tdg(VDS) time.

STDRIVE102BH, STDRIVE102H

Device description

DS14545 - Rev 1

page 29/56

STDRIVE102H Datasheet(PDF) 29 Page - STMicroelectronics