L9908 datasheet(35/153 Pages) STMICROELECTRONICS

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Table 29. Fault output redirection configuration bit

<FLT_REF>_REDIRECT_CFG

Description

Fault redirected on FS_FLAG/IC ERR (Default)

Fault redirection masked

Figure 14. Fault output redirection logic simplified block diagram

5.6.2

Fault reaction scenarios

Here below are described the scenarios of each different fault case separately.

In case multiple faults take place at the same time the following priority in reaction is used:

•

STD fault

•

Auto-retry

•

Reduced operation mode

•

WRN fault

5.6.2.1

Shutdown faults

When a shutdown fault is detected, the related SPI flag is set to ‘1’, the IC ERR bits in the SPI FRAME are set to

‘11’ and the FS_FLAG is asserted low.

Disable logic reacts by establishing SAFE_OFF mode: all the three half bridges are disabled, with VGHS_n-

VSHS_n = 0 V and VGLS_n-VSLSn = 0V [n = 1, 2, 3]. Gate Drive Supply block is disabled (SPI configuration bit

HBn_DIS, CP1_EN and CP2_EN remain set as previously configured).

The SAFE_OFF mode can be left when all the following conditions are met in the following sequence:

STD fault is removed;

STD fault flag is cleared on read (action required by Application SW);

EN_BR is asserted low for at least T_clear and then asserted back high (action required by Application SW).

L9908

Fault Handling Management (FHM)

DS13546 - Rev 3

page 35/153

L9908 数据表(PDF) 35 Page - STMicroelectronics