ZHCSJU7 May 2019 DRV8340-Q1
PRODUCTION DATA.
The GHx and GLx pins are monitored such that if the voltage on the external MOSFET gate does not increase or decrease after the tDRIVE time, a gate driver fault is detected. This fault may be encountered if the GHx or GLx pins are shorted to the PGND, SHx, SLx, or VM pins. Additionally, a gate driver fault may be encountered if the selected IDRIVE setting is not sufficient to turn on the external MOSFET within the tDRIVE period. After a gate drive fault is detected, all external MOSFETs are disabled and the nFAULT pin driven low. In addition, the FAULT, GDF, and corresponding VGS bits are latched high in the SPI registers. Normal operation starts again (gate driver operation and the nFAULT pin is released) when the gate driver fault condition is removed and a clear faults command is issued either through the CLR_FLT bit or an ENABLE reset pulse (tRST). In the SPI device, setting the DIS_GDF bit high disables this protection feature. If DIS_GDF bit is set high and a gate drive fault occurs, the device keeps operating but the appropriate VGS fault bit is set high in the SPI register until cleared through the CLR_FLT bit or an ENABLE pin reset pulse (tRST). GDF cannot be disabled in the H/W device option.
Gate driver faults can indicate that the selected IDRIVE or tDRIVE settings are too low to slew the external MOSFET in the desired time. Increasing either the IDRIVE or tDRIVE setting can resolve gate driver faults in these cases. Alternatively, if a gate-to-source short occurs on the external MOSFET, a gate driver fault is reported because of the MOSFET gate not turning on. The tDRIVE time also refers to the GDF fault blanking time.
Fault handling is done as follows based on the MODE setting: