STGAP1ASTR datasheet(37/70 Pages) STMICROELECTRONICS

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STGAP1AS

Functional description

An echo function is implemented in order to check that input commands toward the gate are

correctly propagated to the driver's output. In case something should prevent the correct

propagation of the command, the driver is able to detect this condition and will start a new

communication (echo) in order to set the desired output state. This process has typical

duration of 4 µs.

7.14

Security check functions

The device allows verifying the gate and sense resistor connections and the functionality of

SENSE and DESAT. This can be achieved through the following security checks:



GON to gate path



GOFF to gate path



SENSE comparator



SENSE resistor



DESAT comparator

The check modes are enabled through a dedicated configuration register TEST1 (refer to

Section 9.2.9 on page 63

) and thus require entering in configuration mode.

Only one check mode at a time must be enabled. At the end of security check procedure,

the TEST1 register must be set to 0x00 before running the device in normal mode.

It is recommended to clear the status register with the ResetStatus command before and

after each check.

To prevent the SD from clearing the STATUS flags, set the SD_FLAG = '0' as described in

Section 7.11

7.14.1

GON to gate path check

The purpose of this security check is to verify the path integrity including the driver's GON

output, the GON (turn-on) gate resistor, the power switch gate and the CLAMP pin (see

Figure 17

To perform this test, the following procedure has to be followed:



Set SD = low



Send StartConfig command



Set GONCHK = '1'



Send StopConfig command



Wait tGchk



Read TSD flag

–TSD = '0' → OK (VCLAMP > VGchk)

–TSD = '1' → FAIL (VCLAMP < VGchk)

Please note that during all the time the check is enabled the gate will be forced high (GON

turned on) regardless the SD pin level. The user test routine has to take into account this

behavior.

In any case, when GONCHK = '1', the protections SENSE and DESAT, if enabled, will

continue to operate protecting the power switch regardless the SD pin.

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