This board is designed for small power-conscious projects, while still boasting a high output current (2+ amps!)
It is powered of a single cell Lithium Ion battery and charged via a micro USB port.
While off, the board consumes less than 2µA! Features automatic low voltage shutoff and short circuit protection.
A red and green LED provide straightforward information about the battery.
- Green LED On - Power Supply On
- Green LED On and Red Blinking - On with low battery
- Green LED On and Red Blinking rapidly - On with critical battery
- Green LED Glowing/Fading - On and charging
- Red LED Glowing/Fading - Off and charging
- Red LED On - Off and charged
Update 11/7/17: I'm working on a 3.3V and 5V version of this power supply with a expected completion in Feburary 2017.
Update 2/10/17: Revision 5 works great and is the final version.
Update 5/8/17: 1.8V, 3.3V, and 5V variants are complete
- Battery connector from JST-PH to JST-XH
- Improved grounding
- Increase board size (better heat dissapation)
- Add solder connection for batteries with JST connector
- Fix ISP silkscreen label
- Remove adjustable charge current
- Add R9 C9 for improved transient on load step
- Increase board size (traces too close to edge)
- Add adjustable charge current via jumper
- Silkscreen improvements
- Pull up/down resistors to 20K from 10K
- New LEDs
- Increase hole size for output and ISP pins
- Add switch for LEDs (to save power)
- Use SMT switches instead of through hole
- Add 500mA fuse for USB
- Increase output capitance to from 47uF to 141uF
- Add pull down resistor for USB sense (R6)
- Move pull up resistor R3 across switch