4.1.4

OVC and STG

Overcurrent protections act sensing the voltage drop across an external shunt resistance, connected between

SENSE and OUT pin.

The OVC thresholds and related filter time depend on the status of the output voltage, if a short to GND condition

is also detected or not.

•

In case of no short to ground detected on the output voltage

–

the OVC threshold voltage is OC_HV_th and the OVC filter time is OC_HV_flt.

–

during overcurrent detection, while the filter time OC_HV_flt is applied, shall the current increase and

the voltage across the shunt go above the threshold OC_HV_fast_th, the filter time is shortened to the

value OC_HV_fast_flt.

•

In case of short to ground detected on the output voltage:

–

the OVC threshold voltage is OC_LV_th and the OVC filter time is OC_LV_flt.

–

during overcurrent detection, while the filter time OC_LV_flt is applied, shall the current increase and

the voltage across the shunt go above the threshold OC_LV_fast_th, the filter time is shorted to the

value OC_HV_fast_flt.

This architecture provides additional protection in case of output shorted to GND, lowering the threshold value.

Moreover, if a strong overcurrent condition is detected (current exceeding the HV_fast or LV_fast thresholds), the

filter time is also shortened in order to limit as much as possible high current levels through external FETs (see

Figure 6). When overcurrent detection time is expired, the HGATE and DGATE external FET are driven OFF by

the internal pulldown. Auto-retry function is present, and it is described in Section 4.2.2 Overcurrent auto retry.

Figure 6. Overcurrent digital architecture

STPM801

Functional behavior in detail

DS13990 - Rev 2

page 13/38