LED 드라이버용 Fibonacci-Type Switched-Capacitor AC-DC Converter를 동작시키기 위한 구동회로 설계

This paper presents control circuits for an AC-DC converter based on a Fibonacci-type switchedcapacitor (SC) DC-DC converter. To adopt the advantages of conventional SC DC-DC converter to an AC-DC application, the proposed AC-DC converter adaptively reconfigure its recharge path of flying capacitors according to the AC input. A simple ADC (Analog-to-Digital converter) block based on flash-type ADC is used to make switch control signals according to the AC input voltage. The switch control block makes 25-bits driving signals for power switches using bootstrapped switch drivers. Also, the current regulation block can change the division ratio of output voltage to change operating mode smoothly. The proposed AC-DC converter simulated in 0.18μm BCDMOS technology has a total power efficiency of 61.7%, DC output voltage of 5.2V and a peak-to-peak output voltage ripple of 140mV.