Quasi-resonant switch-mode isolated lithium-ion battery charger with CC-CV modes of operations using secondary side controller

This paper presents a quasi-resonant switch-mode isolated battery charger for charging Lithium-Ion (Li-Ion) batteries. It has two modes of operation: constant current (CC) and constant voltage (CV). The quasi-resonant flyback topology is selected to implement this charger because it has a few parts. It is controlled by the accurate and cost-effective secondary side analog controller which has the appropriate feedback loop compensation. The charging current is controlled by the output current control loop. This charger has low output voltage ripple and high efficiency too. The operation and performance of this charger have been verified by the experimental results. For this purpose a 12.6V, 2000mA Li-Ion charger is designed for charging three series 3.7V, 2200mAh Li-Ion batteries.