An ultra-low input flyback converter with wide conversion ratio utilizing zero-current switching techniques

An ultra-low input flyback converter is proposed in this paper. Instead of the conventional flyback topology, the improved topology is able to reduce more power consumption to achieve high efficiency by replacing the output diode with a power transistor. This design can achieve wide conversion ratio and high conversion efficiency by utilizing transformer and digitally controlled zero-current switching techniques operates from input voltage 20 mV to 250 mV while supplying an output 1.8V, delivers maximum 18 mW of output power and 92.63% efficiency for a 250 mV input. The proposed circuit has been designed with TSMC 0.18μm CMOS 1P6M processes. The total chip area is 1.19 × 1.18mm² with PADs.