14 mm Round Li-ion Charger PCB
Budget: $30 – $250 USD
I’m building a miniature device powered by a 3.7V Battery Lithium Polymer 160 mAh cell and I need a full, ready-to-manufacture charging board. The board must be perfectly round, exactly 14 mm in diameter, and include the following on that tiny footprint:
The battery will power a small led wire for about 50cm. So a small pushbutton or similar to turn the led wire on/off.
• A reliable battery protection circuit (over-charge, over-discharge, short-circuit).
• A clear LED status indicator (charging / full).
• A USB Type-C input for power.
Because space is so limited, I’m happy for you to suggest the most sensible charge method and rate—constant-current/constant-voltage, pulse, or a hybrid—so the battery’s health is protected while keeping heat low.
Scope of work
1. Schematic design with all protection and indicator circuitry.
2. Compact PCB layout that honours the 14 mm round outline and positions the USB-C, LED, and test pads logically.
3. Complete manufacturing package: Gerbers, drill files, pick-and-place, and clear assembly notes.
4. Bill of Materials with readily available parts (prefer 0603 or smaller passives, but I can be flexible if you justify it).
5. A brief application note explaining recommended charge current, expected thermal performance, and any tuning resistors.
Feel free to use KiCad, Altium, Eagle, or another mainstream tool—just tell me which so I can open the files later in EasyEDA.
Deliverables should be production-ready; I’ll be sending them straight to my PCB house.
If you have experience squeezing USB-C and Li-ion protection onto coin-sized boards, let’s talk.
The battery will power a small led wire for about 50cm. So a small pushbutton or similar to turn the led wire on/off.
• A reliable battery protection circuit (over-charge, over-discharge, short-circuit).
• A clear LED status indicator (charging / full).
• A USB Type-C input for power.
Because space is so limited, I’m happy for you to suggest the most sensible charge method and rate—constant-current/constant-voltage, pulse, or a hybrid—so the battery’s health is protected while keeping heat low.
Scope of work
1. Schematic design with all protection and indicator circuitry.
2. Compact PCB layout that honours the 14 mm round outline and positions the USB-C, LED, and test pads logically.
3. Complete manufacturing package: Gerbers, drill files, pick-and-place, and clear assembly notes.
4. Bill of Materials with readily available parts (prefer 0603 or smaller passives, but I can be flexible if you justify it).
5. A brief application note explaining recommended charge current, expected thermal performance, and any tuning resistors.
Feel free to use KiCad, Altium, Eagle, or another mainstream tool—just tell me which so I can open the files later in EasyEDA.
Deliverables should be production-ready; I’ll be sending them straight to my PCB house.
If you have experience squeezing USB-C and Li-ion protection onto coin-sized boards, let’s talk.