Is it possible to separate the H-Bridge voltage from the Power supply : SKU:DRI0042

Conceptually you can keep the H-bridge (motor) supply separate from the control/logic supply, and you can bring the H-bridge voltage to 0 V while keeping the controller powered — but for the DFRobot DRI0042 the board as-sold derives its 5 V logic from the motor supply, so you must take one of a few careful approaches to get the result safely. It is recommended that you use a separate motor supply + a separate logic supply.