LiPo Battery (3.7V) Charger PCB
PCB Information
- Category: Power Management
- Design Tool: KiCAD 9
- Date: April 2025
- Board Size: 18 × 20mm
- Layers: 2-layer
- Total Cost: RM11.45
- Download Gerber Files
- View on GitHub
Project Overview
This PCB design implements a single-cell LiPo battery charging circuit based on the MCP73831-2-OT controller IC. The design provides a compact, efficient solution for safely charging lithium polymer batteries with built-in status indication and protection features.
Schematic Analysis
Input Section
- 4.7μF bypass capacitor for input stability
- USB Micro-B connector for power input
Charge Controller
- MCP73831-2-OT in SOT-23-5 package
- 2kΩ PROG resistor sets 500mA charging current
Status Indication
- Red LED with 470Ω current-limiting resistor
- Indicates charging status (on/off)
Output Section
- 4.7μF output bypass capacitor
- JST connector for battery connection
Design Justification
IC Selection
- Complete charging solution in small package
- Built-in thermal regulation
- Automatic charge termination
- Low quiescent current (20μA)
Layout Guidelines
- Wide power traces (20mil minimum)
- Components placed close to IC
- Ground plane for EMI reduction
Thermal Management
- Copper pour for heat dissipation
- Thermal vias under the IC
Bill of Materials
| Component | Description | Value/Part | Qty | Unit Price | Supplier |
|---|---|---|---|---|---|
| U1 | LiPo Charger IC | MCP73831-2-OT | 1 | RM3.39 | element14 |
| R1 | Resistor | 2kΩ, 1206 | 1 | RM0.02 | element14 |
| R2 | LED Resistor | 470Ω, 1206 | 1 | RM0.035 | element14 |
| C1, C2 | Bypass Capacitors | 4.7μF, 16V, 0603 | 2 | RM0.59 | element14 |
| D1 | Status LED | Red, 0603 | 1 | RM4.20 | Shopee |
| J1 | USB Connector Micro-B | 105017-0001 | 1 | RM2.82 | element14 |
| J2 | Battery Connector | JST PH 2-pin 1.25mm | 1 | RM0.40 | Shopee |
| Total Cost: | RM11.455 | ||||