Li-ion battery management chip for multi-cell battery pack

This paper introduces a method of realizing a monolithic battery management chip for a lithium ion battery pack of multi-cell in series. High precision subtractor amplifiers were employed to extract the voltage information of each battery. With the utilization of the subtractor amplifiers, the whole system was allowed to be implemented in a normal, nonexpensive standard CMOS process with 5 V supply voltage, instead of a costly high-voltage process. A testing chip was implemented by using CSMCpsilas 0.5 mum 5 V N-well CMOS process. The chip was designed for double-cell battery pack and compatible with single-cell application. The testing results showed this chip functioned well in both applications of double-cell and single-cell, and revealed that the present design method would be suitable for the multi-cell battery packs.