Cherry Bomb

A compact, simple, easy-to-use OSHW 1S li-ion battery charger and 5V boost converter, for Raspberry Pi projects and other portablizing applications, utilizing BQ25616RTWR and TPS61022RWUR.

Specs:

• Tiny 19 x 11mm PCB
• BQ25616 4.2V, 2.5A 1S Li-ion charger (1S ONLY!)
• 5V - 12V recommended VBUS voltage
• PG (power-good) and STAT (charge indicator) LEDs
  
  
• Onboard TPS61022 fixed 5V/3A boost converter
• ~3A max output current
  
• Auto-PFM mode for decent efficiency at low loads
• 90 - 95% efficient

Usage:

Please see the charger IC datasheet (BQ25616RTWR) for specifics!

• These regulator boards are cheap, simple modules for quick and dirty builds. Don't expect perfection!
• Connect a single-cell (1SxP) Li-ion pack to VBAT and GND
• Connect a 5V - 12V 3A input source to the VBUS and GND pins to charge the pack at up to 2.5A. Charge cutoff is fixed at 4.2V.
• Cherry Bomb does not handle cell protection! Use a PCM and/or housekeeping microcontroller to avoid battery damage!
  
  
• The 5V boost converter is disabled by default. Connect the EN pin to 1.8V-5.5V to enable the regulator and output 5V at up to 3A.
• Cherry Bomb does not need external capacitors. However, some applications may benefit from external electrolytic caps, especially if the 5V load is far away.
• Cherry Bomb is thermally limited since it uses a basic 2-layer PCB. Expect it to reach relatively high temperatures while charging, and expect charging to slow down if the 5V regulator is in use during charging. You can mount Cherry Bomb to a larger board, or put a heatsink on the BQ, to improve its thermal performance.

PCB designed in KiCAD. Manufactured and assembled by JLCPCB. Tested in New Mexico.

Source: https://github.com/mackieks/cherry_bomb