SLUSDH7C February 2019 – January 2024 UCC21732-Q1
PRODUCTION DATA
The RST/EN pin has two functions. It can be used to enable and shutdown the outputs of the driver, and reset the fault signaled on the FLT pin. RST/EN pin needs to be pulled up to enable the device; when the pin is pulled down, the device is in disabled status. With a 50-kΩ pulldown resistor existing, the driver is disabled by default.
When the driver is latched after overcurrent or short circuit fault is detected, the FLT pin and output are latched low and need to be reset by RST/EN pin. RST/EN pin is active low. The microcntroller needs to send a signal to RST/EN pin after the fault mute time tFLTMUTE to reset the driver. This pin can also be used to automatically reset the driver. The continuous input signal IN+ or IN- can be applied to RST/EN pin, so the microcontroller does not need to generate another control signal to reset the driver. If non-inverting input IN+ is used, then IN+ can be tied to RST/EN pin. If inverting input IN- is used, then a NOT logic is needed between the inverting PWM signal from the microcontroller and the RST/EN pin. In this case, the driver can be reset in every switching cycle without an extra control signal from microcontroller to RST/EN pin.