8.3.1.4.4 MOSFET V_DS Monitors

The gate drivers implement adjustable V_DS voltage monitors to detect overcurrent or short-circuit conditions on the external power MOSFETs. When the monitored voltage is greater than the V_DS trip point (V_{VDS_OCP}) for longer than the deglitch time (t_OCP), an overcurrent condition is detected and action is taken according to the device V_DS fault mode.

The high-side V_DS monitors measure the voltage between the VDRAIN and SHx pins. In devices with three current sense amplifiers (DRV8323 and DRV8323R), the low-side V_DS monitors measure the voltage between the SHx and SPx pins. If the current sense amplifier is unused, tie the SP pins to the common ground point of the external half-bridges. On device options without the current sense amplifiers (DRV8320 and DRV8320R) the low-side V_DS monitor measures between the SHx and SLx pins.

For the SPI devices, the reference point of the low-side V_DS monitor can be changed between the SPx and SNx pins if desired with the LS_REF register setting.

The V_{VDS_OCP} threshold is programmable from 0.06 V to 1.88 V. For additional information on the V_DS monitor levels, see the Register Maps section for SPI devices and in the Pin Diagrams section hardware interface device.

Figure 28. DRV8320 and DRV8320R V_DS Monitors

Figure 29. DRV8323 and DRV8323R V_DS Monitors