A 10/30 MHz Fast Reference-Tracking Buck Converter With DDA-Based Type-III Compensator

A 10/30 MHz voltage-mode controlled buck converter with a wide duty-cycle range is presented. A high-accuracy delay-compensated ramp generator using only low-speed comparators but can work up to 70 MHz is proposed. By using a differential difference amplifier (DDA), a new Type-III compensator is proposed to reduce the chip area of the compensator by 60%. Moreover, based on the unique structure of the proposed compensator, an end-point prediction (EPP) scheme is also implemented to achieve fast reference-tracking responses. The converter was fabricated in a 0.13 μm standard CMOS process. It achieves wide duty-cycle ranges of 0.75 and 0.59 when switching at 10 MHz and 30 MHz with peak efficiencies of 91.8% and 86.6%, respectively. The measured maximum output power is 3.6 W with 2.4 V output voltage and 1.5 A load current. With a constant load current of 500 mA, the up-tracking speeds for switching frequencies of 10 MHz and 30 MHz are 1.67 μs/V and 0.67 μs/V, respectively. The down-tracking speeds for 10 MHz and 30 MHz are 4.44 μs/V and 1.56 μs/V, respectively.