Small-Signal Modeling Analysis for a Battery Charging Application

This paper discusses the small-signal modeling analysis of a lithium battery charger that uses a synchronous buck converter to achieve dual-mode control. The dual-mode control can enable a circuit to operate in constant current and voltage modes. Further, this paper discusses the difference between the battery and resistance models as the output load for a constant current small-signal modeling analysis. It compares the difference between the two load models for system stability. The paper also proposes a method of designing a compensator with a battery model as a load. Finally, a battery charger converter with an input voltage of 9 V, an output voltage of 3.8 V, and a constant current of 1.3 A was used to verify theoretical simulation and circuit verification.