Tool/software:
Hello TI team,
We designed a PCB using the BQ25750 charger IC (based on the BQ25750EVM) to charge a supercapacitor stack. The input voltage and the target stack voltage are both 24V. The register parameters are shown below. The circuit does the intended functionality and works in both forward and reverse modes. However, we are witnessing some ripple in the charging current (red circle region) when the capacitor voltage is close to its target value. A close look at the gate signals of one of the low side switches shows missing gate signals in the noise region. we were able to reduce this noise by setting the lowest deadtime option (45ns), but the noise is not gone completely. We also tried changing the switching frequency but it didn't help. The supercapacitor stack is connected to our boards with 8" twisted pair. Any suggestions as to why those gate pulses are missing and how could we remove the noise completely? Thanks.