Hi everyone,
We’re currently working on a project utilizing the MP2632 to charge and manage a single-cell lithium-ion battery (3.7V nominal). Our design has been validated with a functional board using the MP2632B, giving us confidence in the PCB layout and component selection.
However, after transitioning from the MP2632B to the MP2632 (To disable the Automatic Off at Light Load feature). We started experiencing an atypical behaviour: the chip oscillates in a repeated on-off cycle around 2.8 Hz. Although our board is powered by a stable 5V from a bench supply, we observed intermittent dips in the input voltage to the MP2632, which prevents the chip from achieving a full startup.
When swapping back to the MP2632B (same board), we encountered the same on-off cycling issue.
Has anyone encountered similar behaviour with either the MP2632 or MP2632B?
Is it possible that this is a result of the MP2632 chips being compromised during assembly (e.g., from ESD, overvoltage, or thermal stress), which could explain this persistent cycling?
So far, we’ve taken several steps:
- Verified that the decoupling capacitors, sense resistors, and NTC resistor divider configurations are accurate.
- Assembly only the power management side of the board to see if it was a load problem.
- Reflow to make sure no bad pin connections.
- Observed that the SW node does not show the expected high-frequency PWM pulses
Any insights from your experiences or recommended diagnostic tests to further investigate this issue would be greatly appreciated!
Thank you for your assistance.