How can EPS driver power supplies isolate and resist interference?

Providing isolated power to the power device drive circuit of EPS is crucial for cutting off power ground noise interference and ensuring reliable drive.

Isolation methods:

1. Isolated DC-DC module: Use a dedicated isolated DC-DC power supply module to power each drive bridge arm (especially the high-voltage side). The module should have sufficient isolation voltage and low coupling capacitance.

2. Discrete isolation scheme: Use push-pull or flyback topology, and build it yourself with isolation transformer and rectifier circuit.

Regardless of the method, the design points include:

1. Y capacitor across primary and secondary sides: Connect a small-capacity safety-certified Y capacitor (e.g., 10pF-100pF) between the primary and secondary sides of the isolation transformer or between the input and output of the isolation module to provide a loop for the high-frequency common-mode noise generated by the drive chip and prevent it from coupling through the isolation barrier.

2. Power supply decoupling: Place high-quality decoupling capacitors near the power supply pins of the drive IC.

3. Compact layout: The isolated power supply should be as close as possible to the driven power device to shorten the drive loop.