MCP1630 LOW-COST BATTERY
CHARGER USER’S GUIDE
©
2005 Microchip Technology Inc.
DS51555A-page 7
Chapter 2. Installation and Operation
2.1
INTRODUCTION
The MCP1630 Low-Cost Li-Ion Battery Charger demonstrates Microchip’s high-speed
Pulse Width Modulator (PWM) (the MCP1630) used in a battery charger application.
The MCP1630 is a high-speed, microcontroller-adaptable PWM. When used in
conjunction with a microcontroller, the MCP1630 will control the power system duty
cycle to provide output voltage or current regulation. The microcontroller (a
PIC12F683) can be used to regulate output voltage or current, switching frequency and
maximum duty cycle. The MCP1630 generates duty cycle and provides fast
overcurrent protection based off various external inputs. External signals include the
input oscillator, the reference voltage, the feedback voltage and the current sense. The
output signal is a square-wave pulse. The power train used for the MCP1630 Low-Cost
Li-Ion Battery Charger is a Single-Ended Primary Inductive Converter (SEPIC).
2.2
FEATURES
The MCP1630 Low-Cost Li-Ion Battery Charger has the following features:
• Programmed parameters - modified in firmware
• Factory Settings:
- Preconditioning Charge Current = 200 mA
- Preconditioning Threshold = 3 V
- Constant Current Fast Charge = 2 A
- Constant Voltage Charge = 4.2 V
- Charge Termination Threshold = 100 mA
• Overvoltage protection (battery removed)
• Overcharge protection to prevent damaging the battery
• Overcurrent protection in the event of a shorted battery
• Battery reversal protection
• Input short circuit protection
• Overtemperature protection to prevent the battery from reaching too high a
temperature during charge
• Soft-start capability by holding the reference voltage low during power-up
• The MCP1630 Low-Cost Li-Ion Battery Charger terminates charge by detecting a
predefined charge current threshold during constant voltage charge, or a specified
elapsed time
• The MCP1630 Low-Cost Li-Ion Battery Charger has the flexibility to optimize the
charging algorithm for new battery technology, different battery chemistries or
different battery pack configurations
• Proprietary features can be added by modifying the firmware contained in the
PIC12F683
• The factory-programmed source code is available
• Ability to adapt to environmental effects, such as ambient temperature
