Electrical – Bulk Capacitance inrush current limiting solutions

Fundamental in the design of a H bridge that drives a dc motor is a bulk storage capacitor across the H bridge supply. This capacitor “soaks” up the leftover energy in the motor that will force itself onto the power rail. Therefore that capacitance (implied by your circuit) acts to somewhat stabilise the voltage supply and, in many cases it can recover braking energy.

So, the four capacitors in your circuit can be regarded as equivalent to a main bulk supply capacitor and a local arc suppression. There are many ways to skin a cat of course.

Personally I don’t like the four capacitor approach because the mosfets have a hard enough time with their own parasitic capacitance. My preference is a good solid bulk capacitor across the rails and an RC snubber across the motor but, like I said, there are many ways....

If the module you bought contains a real LTC3780, you do not need any downstream protection for it, as it is already short circuit protected.

If the chip on there is made of chinesium, and you do not trust it, you can try and hack the board to regulate the inrush current changing the cap connected to the SS pin. Limiting the inrush current will surely also limit the output current, saving the board.