5.6

Protections management summary

A summary of the protections and the effects on the functional blocks of the device can be found in Table 16. The

protections embedded in the STDRIVE102BH/H ensure a safe operation for the gate drivers and the external

power stage. The protections include:

•

Undervoltage lock-out (UVLO) for:

–

12 V LDO regulator: VCC supply (Section 5.1.1)

–

3.3 V LDO regulator: VDD supply (Section 5.1.2)

–

Charge pump: VBOOT - VM supply (Section 5.1.3)

•

VDS monitor protection (Section 5.2.3)

•

AFE comparators protection (Section 5.3)

•

Thermal shutdown protection (Section 5.5)

When a protection is triggered, the nFAULT pin is kept low as long as the FAULT condition is released. Depending

on the fault condition one or more functional blocks are disabled.

In addition to the protections listed above, the STDRIVE102BH reports a warning event on the FLAG pin, in case

the VCC supply of the drivers falls below the power-good threshold VP_GOOD(Off). The FLAG pin provides the

indication that the VCC is low and the drivers are operating with a reduced voltage. The FLAG pin is intended to

be an early warning before the actual protection that is the UVLO on the VCC pin. When VCC falls below the

VP_GOOD(Off) threshold, the open-drain FLAG pin is set low and it is released when the VCC rises above the

VP_GOOD(On) threshold (refer to Figure 7). The power-good warning does not impact on the drivers operation,

which continue working according to their driving input signals.

During the thermal shutdown, as the power-good monitoring turns off together with the VCC linear regulator, the

FLAG open-drain pin is forced low. Even if the VCC pin is forced by an external voltage higher than the

VP_GOOD(On) threshold, the FLAG pin is forced low, because the circuitry controlling the power-good signal is

disabled. After the thermal shutdown, the regulator is enabled again and the FLAG pin is released as soon as the

VCC increases above the VP_GOOD(On) threshold.

Table 16. Device protections summary

Protection

Condition

Driver

HS

Driver

LS

12 V LDO

3.3 V

LDO

Charge

pump

Release condition

Notes

UVLO VCC

VCC < VCC(Off)

LOW

LOW

Active

Active

Active

VCC > VCC(On)

UVLO VDD

VDD <

VDD(Off)

LOW

LOW

Active

Active

Active

VDD > VDD(On)

The AFE could

not work

properly,

drivers are

disabled

Charge pump

UVLO

(VBOOT - VM) <

VCPump(Off)

LOW

Active

Active

Active

Active

(VBOOT - VM) >

VCPump(On)

Thermal

shutdown

Tj > Tj(THSD)

LOW (1)

LOW (1)

Disable

Disable

Disable

Tj < Tj(THSD),rec

Both nFAULT

and FLAG are

forced low

VDS monitor

VDS > VDS,th

LOW

LOW

Active

Active

Active

Standby or EN forced

low (< Vrelease)

AFE comparators

VC_INx > VCREF

LOW

LOW

Active

Active

Active

Standby or EN forced

low (< Vrelease)

Warning on VCC

(2)

VCC < VP_GOOD(Off)

Active

Active

Active

Active

Active

VCC > VP_GOOD(On)

Warning only, it

is reported on

FLAG pin

1. The drivers can force LOW the MOSFETs’ gates only if VCC and VBOOT supplies are present. Thermal shutdown turns off both the 12 V

regulator and the charge pump, so the gate drivers’ ability to turn off the MOSFET could be affected.

2. Avaialble only for STDRIVE102BH.

STDRIVE102BH, STDRIVE102H

Device description

DS14545 - Rev 1

page 35/56