A highly accurate constant voltage (CV) and constant current (CC) primary side controller for offline applications

This paper presents an innovative primary-sensing technique for constant voltage (CV) and constant current (CC) for flyback converter, eliminating the need for the opto-coupler, the secondary voltage reference, as well as the current sensor. The voltage regulation can achieve +/−2.5%, and current +/−5%. Furthermore, the control IC is integrated with high voltage (800V) MOSFET, which makes it suitable for low power battery chargers, LED applications, and auxiliary power supplies.