MP2760 SYS supply instability and severe voltage drop under minimal load when operating without a battery

When the MP2760 is operated without a battery connected, the SYS output becomes highly unstable. Even under very light load, the SYS voltage collapses sharply (down to approximately ~2 V) and then recovers. Under no-load conditions, SYS oscillates between its nominal voltage and lower levels.
The input voltage remains stable. While the system operates stably with the battery connected, severe SYS voltage sag occurs under even minimal load when operating without a battery. Below is the VSYS waveform measured under a 500 mA load.

Hi @anil2002kemal,

Are you able to repeat the above testing with charge disabled? This will help isolate whether the presence of the battery is a part of the issue.

You can achieve this by setting REG12h (Configuration Register 4) Bit 0 to value ‘0’ as provided on page 49 of the datasheet. This action will turn off BATFET.

MP2670_CHG_EN

Thank you, Will

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