L99DZ80EP datasheet(38/68 Pages) STMICROELECTRONICS

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L99DZ80EP

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DocID18260 Rev 6

Figure 14. H-bridge GSHx slope

3.17

Resistive low

The resistive output mode protects the L99DZ80EP and the H-bridge in the standby mode

and in some failure modes (thermal shut down (TSD), charge pump low (CP_LOW) and

stuck-at-‘1’ at pin DI). When a gate driver changes into the resistive output mode due to a

failure a sequence is started. In this sequence the concerning driver is switched into sink

condition for 32 µs to 64 µs to ensure a fast switch-off of the H-bridge transistor. If slew rate

control is enabled, the sink condition is slew-rate controlled. Afterwards the driver is

switched into the resistive output mode (resistive path to source).

3.18

Short circuit detection/drain source monitoring

The drain source voltage of each activated external MOSFET of the H-bridge is monitored

by comparators to detect shorts to ground or battery. If the voltage-drop over the external

MOSFET exceeds the threshold voltage VSCd for longer than the short current detection

time tSCd the corresponding gate driver switches the external MOSFET off and the

corresponding drain source monitoring flag (DS_MON[3:0]) is set. The DS_MON bits have

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