STDRIVE102BH datasheet(34/56 Pages) STMICROELECTRONICS

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5.5

Thermal shutdown

The STDRIVE102BH/H has a thermal shutdown protection: if the junction temperature of the device exceeds the

thermal shutdown threshold Tj(THSD), the driver turns off the external power MOSFETs and after a tcc,off the linear

regulators and the charge pump are disabled. The nFAULT pin is forced low (refer to Figure 25).

Note that the blocks generating the supply of the drivers (VCC and VBOOT) are turned off: therefore, the supplies

slowly decrease according to the external capacitor present on the VCC and VBOOT pins. When the capacitors

are fully discharged, the external MOSFETs are kept off only by the 100 kΩ resistors present on each driver’s

output.

Turning off the 12 V regulator results in the turn off of the UVLO and power good circuitry. As a consequence, the

nFAULT is forced low together with the FLAG pin (for the STDRIVE102BH only), regardless the actual voltage on

VCC pin.

As soon as the temperature of the device decreases below the Tj(THSD),rec temperature, all the functional blocks

are enabled again. According to the duration of the thermal transient, the regulators and their different supplies

(VBOOT, VCC and VDD) can decrease below the UVLO threshold. In this case the drivers are enabled and the

nFAULT pin is released as soon as all the UVLO condition is released. In the STDRIVE102BH, the FLAG pin is

released according to the power-good circuitry (refer to Table 16 in the next section).

Figure 25. STDRIVE102BH/H thermal thresholds

nFAULT

Tj(THSD)

Gate drivers active

Gate drivers LOW

VCC(On)

Gate drivers active

VCC

VDD

Gate

Drivers

VCC

(Reg. 12V)

VDD

(Reg. 3.3V)

operative

Device Thermal

shutdown

operative

UVLO

Tj(THSD),rec

STDRIVE102BH, STDRIVE102H

Device description

DS14545 - Rev 1

page 34/56

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