1 Design Specifications

A battery manager has several important functions in a system:
  • Management of battery charging
  • Management of power conversion between the battery and the load
  • Tracking the battery state of charge
  • Tracking the battery health

To do these functions, the system needs to be able to enable/disable both the charger and the output voltage regulator, monitor the various system voltages and currents, and be able to integrate both the charge and discharge current for coulomb counting (gas gauge function).

For this design, the battery used will be a dual cell, 1000 mAH Li-Poly battery, capable of a 20C discharge (20A). The charger ASIC will be an MCP73844 charge controller with an NDS8434 6.5A P channel MOSFET transistor. The load regulator will be an MCP16311 1A high-efficiency step-down regulator. To provide monitoring and control, a PIC16F15244 microcontroller with a 10-bit ADC and PWM will be used.