95% light-load efficiency single-inductor dual-output DC-DC buck converter with synthesized waveform control technique for USB type-C.

The proposed single-inductor dual-output (SIDO) converter can provide wide range in duty ratio control to convert input voltage 520V to dual output voltages 3.3V and 1.2V when its switching frequency is raised to 10MHz for compact size solution. The proposed synthesized waveform control (SWC) technique can emulate the inductor current without being affected by switching noise. Thus, the minimum allowable duty ratio can be lowered to 6% to meet the requirement of USB-C in one-stage low duty ratio conversion. Moreover, the switching frequency is dynamically decreased by the derived DC loading information from the SWC technique. Not only the output power MOSFET but also the main power MOSFET switch in a load-dependent switching frequency for power saving. 67% more power reduction can be obtained. 95% and 83% efficiency are achieved at light and heavy loads, respectively, when the silicon is limited within 1400 mu m*1350 mu m.