How to reduce noise in EPS drive circuit wiring?

The routing quality of the IGBT/MOSFET drive circuit in an EPS directly affects the switching waveform and system EMC. The key to reducing noise is minimizing the parasitic inductance of the drive circuit and ensuring a clean reference ground. Routing guidelines:

1. Loop minimization: The loop area from the driver IC output to the gate and source/emitter of the switching transistor should be as small as possible. This can be achieved using adjacent gate-source traces on the same layer or overlapping traces on a double-sided board.

2. Independent reference ground (Kelvin connection): Provide an independent "drive ground" for the drive circuit. This ground should be directly and with low impedance connected to the source/emitter of the driven switching transistor via a separate trace or pin, rather than returning through the power ground.

3. Decoupling capacitor placement: High-quality high-frequency ceramic decoupling capacitors (e.g., 0.1μF) must be placed near the power supply pins of the driver IC.

4. Gate resistor close to the gate: The gate drive resistor should be placed as close as possible to the gate pin of the switching transistor.

5. High-voltage side drive isolation: Use isolated power supplies and isolated signal transmissions (e.g., optocouplers, isolated drivers).