My schema works as long as the Battery is attached to it.
In fact, it even works if I disconnect the Battery - EXCEPT that the LED1 toggles in that case.
My intention is to use the circuit either
- 5V and Battery connected (to make the battery charge)
- Battery-only (normal usage)
- 5V only connected (for programming and quick tests)
The LED1 toggles wildly in mode 3 (5V without battery-connection). Why ??
The left hand side shows the 5V-to-3.3V conversion (including U1 so that 3.3V is still produced when 5V USB is disconnected)
The right hand side shows the battery-charging circuit (with its main component MCP73832T).
I already added R4=100k between VDD and STAT - but it did not bring anything - the LED1 is still toggling when 5V is disconnected. Shall I connect R4 between VBAT and STAT instead ??
Any idea what to change to stop the LED1 from toggling for 5V supply without Battery-connected ?