This function provides up to 150mA at 3.3V from a LiPo battery and/or an micro-USB connection. It is based on the MCP7383x from Microchip to manage power from the USB port and the LiPo battery, and the TPS78233 from Texas Instruments to regulate it to 3.3V.
What makes it special is the TPL5111 system timer, which makes it easy to create low-power devices. This component will only turn the power on periodically, every few seconds up or to two hours, as defined by a potentiometer on the board. This allows the host to do its work, then send a message to the TPL5111 ask it to turn the power off, for the whole board.
- USB connector
- LiPo battery connector (but not the battery itself)
- power ON/OFF switch
- push button to reset the power timer
- LED indicating whether the LiPo battery is being charged from USB
- you can choose whether or not to connect the USB lines to the host (if it can handle it), so that it can be recognized by a computer via USB