High-precision constant output current control for primary-side regulated flyback converters

The objective of this paper is to propose a high-precision control strategy for the primary-side regulated flyback converter. The primary-side regulated flyback converter with universal input voltage is widely used for low-cost and low power applications such as the LED lighting with constant output currents. However, the conventional primary-side regulation method suffers from the drawback of current inaccuracy and the LED may be easily damaged. Therefore, a high-precision primary-side regulation strategy for the flyback converter with constant output current is proposed. In this paper, the cause of the output current inaccuracy is discussed and the operation principle of the proposed high-precision current control for the primary-side regulated flyback converter is introduced. Hardware experimental measurements are presented to verify the performance of the proposed control strategy.