EVL2643-R-00A – Continuous Audible Noise in Manual Boost Mode During Validation

Dear MPS Support Team,

I am currently validating the EVL2643-R-00A Active Cell Balancer Evaluation Kit in Manual Control Mode and would like your guidance on an issue observed during the boost-balancing operation.

Test Setup:

  • Evaluation Board: EVL2643-R-00A

  • Battery Configuration: Two 18650 Li-ion cells

  • Cell 1 Voltage (Lower Cell): 3.64 V

  • Cell 2 Voltage (Upper Cell): 3.93 V

Buck Mode Test:

  • CLx-MODEx Jumper: Open

  • ENx-Sx-MODEx Jumper: Left in Manual Mode position

  • Result: Buck balancing operates correctly, and charge transfer appears normal.

Boost Mode Test:

  • CLx-MODEx Jumper: Installed (Closed)

  • ENx-Sx-MODEx Jumper: Left in Manual Mode position

  • Result: A continuous audible sound (high-frequency/whining noise) is generated from the evaluation board immediately after enabling boost mode.

My Questions:

  1. Is the observed continuous sound normal during boost-balancing operation on the EVL2643-R-00A?

  2. Could this sound indicate inductor saturation, unstable switching, incorrect jumper configuration, insufficient input/output capacitance, or another issue?

  3. Will this condition prevent or degrade boost-balancing operation?

  4. Are there any recommended checks to verify proper boost-mode operation?

  5. Could the use of only two cells instead of a complete 5-cell stack affect boost-mode behavior on the evaluation board?

  6. Are there any known issues or recommended jumper settings for manual boost-mode validation?

According to the EVL2643-R-00A quick-start guide, boost mode is selected by installing the CLx-MODEx jumper, while buck mode is selected by removing the jumper. My configuration follows this procedure; therefore, I would appreciate any guidance on the source of the audible noise and the recommended troubleshooting steps.

Thank you for your support.

Best Regards,
Pratyay Maity