How do I power a FRDM-KL25Z board with a coin cell battery?

[markgreenaway]

I've been reading posts on the mbed forums, and I'm under the impression that I need to attach a coin cell battery holder to the underside of my FRDM-KL25Z. But is there anything else I need to do? I've tried powering the board through the VIN and GND. It does not power up using a coin cell, but does power up when I connect a 9V battery to VIN and GND. I'd prefer to use a coin cell, because that's much lighter and smaller, and I could attach the battery holder to the board.

Any help would be appreciated. I'm not an electrical engineer :-)

[jeremyzhou]

Hi Mark,

The chip can also be powered by a single Li-ion battery, In the Fig 1, VOUT33 is
connected to VDD. The USB regulator must be enabled by default to power the MCU.
When connected to a USB host, the input source of this regulator is switched to the USB
bus supply from the Li-ion battery. To charge the battery, the MCU can configure the
battery charger.

And you can learn the more information from the refer:

K60 USB regulator Li-ion Use-case Circuit Diagram
Have a great day,
Ping

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