This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ76952: Reference Plane for the MOSFET Gate (Discharge and Charge) PCB Copper Trace.

Part Number: BQ76952

Hi,

The Power MOSFET Gate signals, controlled by the CHG(Pin 45) and DSG(Pin 43) of the BQ76952 are controlled by its internal Drivers using a charge pump. What should be the reference Plane (return Path) while laying out on the PCB?

Should it be BAT+ or BAT-? We want to ensure a fast turn-off for the MOSFETs with the correct reference and with minimal Inductance.

Regards

Anvin

  • Hello Anvin, 

    Like you said, the return path is internal. You can see the return paths for the CHG/DSG FETs in our Multiple FETs app note (Figure 7-3. CHG Driver Turn-Off Current Path and Figure 9-1. DSG Turn On Current Path). Just ensure good layout practices for the gate drive and wide traces for the power path to ensure minimal inductances.

    Turn-off time would depend on the gate resistances or turn-off circuits you may have. The app note also discussed these.

    I'd also recommend to read the following app note: Driving Parallel MOSFETs Using the DRV3255-Q1. Which is for a different device, but does provide some good recommendations when creating a good layout (Specifically if using Multiple FETs in parallel)

    Best Regards,

    Luis Hernandez Salomon