DRV8872-Q1: Surge Protection

Hey Andy,

While the DRV8872-Q1 integrated motor driver provides some level of built-in protection, it may not be sufficient for driving high voltage relays due to the potential for inductive kickback surges. These surges can damage the driver if not properly addressed.  DRV8872 has overcurrent protection (OCP) and thermal protection (TSD), but it cannot protect itself from overvoltage events.  

A couple of options to implement externally:

1. Flyback Diode:

Adding a flyback diode across the relay coil provides an alternative path for the surge current, protecting the driver from damage. Choose a diode with a voltage rating exceeding the relay coil voltage and a current rating exceeding the peak surge current.  Select a fast-switching diode with a voltage rating at least 50% higher than the relay coil voltage and a current rating exceeding the peak surge current (typically 10 times the nominal coil current).

2. RC Snubber:

An RC snubber circuit consisting of a resistor and capacitor connected in parallel across the relay coil can further improve the surge suppression. The resistor dampens the surge current, and the capacitor absorbs the energy.

Best,

Jacob