STDRIVE102BH datasheet(31/56 Pages) STMICROELECTRONICS

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Figure 23. STDRIVE102H AFE block diagram

OA_INP

CREF

Op-amp

Comp

to Control

Logic

OA_INN

OA_O

C_IN1

VDD

AGND

Comp

C_IN2

VDD

AGND

Deglitch

filter

tdg(COMP)

to Control

Logic

Deglitch

filter

tdg(COMP)

The operational amplifiers are unity-gain stable for load capacitors up to 100 pF and have a low input bias current.

They provide a rail-to-rail input and output operation, a wide bandwidth, and a fast recovery of the output after

saturation. The operational amplifiers are totally uncommitted, so they can be used as general-purpose

components within their operative range (between 0 V and VDD). As an example of typical configuration, the

operational amplifiers can be used to amplify the voltage drop across the shunt resistors placed on the low-side

half-bridge, in order to implement a current sense on each phase. Therefore, the STDRIVE102BH is suitable for

triple shunt applications, while the STDRIVE102H is suitable for single shunt applications.

The comparators in the AFE, three in the STDRIVE102BH and two in the STDRIVE102H, have a single CREF

pin, in common to all the negative inputs as shown in Figure 22 and Figure 23. The positive input of each

comparator has a dedicated pin (C_INx). As an example of typical configuration, the comparators can be used to

implement an overcurrent protection, an overvoltage protection or an overtemperature protection for the

application, in case an external temperature sensor is present in the application.

When the voltage on the positive input of one comparator (C_INx) exceeds the voltage on CREF for a time longer

than the deglitch time (tdg(COMP)), the comparator’s output triggers the protection circuitry and raises a FAULT

event, which forces the nFAULT pin low. At the same time, the power stage is disabled turning off all the external

MOSFETs with the soft-off feature (see Section 5.4). The FAULT condition triggered by the comparators is

latched: the normal operation is restored bringing the EN pin below the Vrelease threshold for a time longer than

tEN,pulse_rel (refer to Figure 24).

Figure 24. AFE comparator example

tdg(COMP)

nFAULT

Gate

Drivers

deglitch

time

CINx

VCREF

comparator protection

FAULT latched

Gate driver LOW

FAULT released

EN = 0

operative

Gate driver active

operative

Gate driver active

Vrelease

tEN,pulse_rel

STDRIVE102BH, STDRIVE102H

Device description

DS14545 - Rev 1

page 31/56

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