I am designing a very small wearable product that uses the XIAO. The XIAO is stacked with a custom PCB with an IMU, a Bluetooth module, and a battery. The board has a charging circuit and regulator on it. My question involves how to connect these to the XIAO.
I should be able to connect the regulator output (+5) to the 5V pin of the XIAO. The schematic shows a diode from the VUSB line. Should I add the same diode to the regulator output before connection to the XIAO 5V pin? (If so, what diode do you recommend?)
The second part of the question is where to connect the input to the charging circuit (MCP73833)? Normally, this would connect to VUSB. If no USB connection was present, the charging circuit would be inactive. When USB power is present, the charger would monitor the battery and charge if necessary. The output of the charger circuit is connected to the battery and the regulator. VUSB is not available on the XIAO.
Is this the right way to add a battery with charging circuit to the XIAO? Do you have any other recommendations?