A 10/30 MHz Fast Reference-Tracking Buck Converter With DDA-Based Type-III Compensator Lin Cheng, Student Member , IEEE, Y onggen Liu

Abstract

A 10/30 MHz voltage-mode controlled buck con- verter with a wide duty-cycle range is presented. A high-a ccuracy delay-compensated ramp gener ator using only low-speed com- parators but can work up to 70 MHz is proposed. By using a differential difference ampli fier (DDA), a new T ype-III compen- sator is proposed to reduce the chip area of the compensator by 60%. Moreover, based on the unique structure of the pro- posed compensator, an end-point prediction ( EPP) scheme is also implemented to achieve fast refe rence-tracking responses. The converter was fabricated in a 0.13 ms t a n d a r dC M O Sp r o c e s s .I t achieves wide duty-cycle ranges of 0.75 and 0.59 when switching at 10 MHz and 30 MHz with peak ef ficiencies of 91.8% and 86.6%, respectively. The measured m aximum output power is 3.6 W with 2.4 V output voltage and 1.5 A load cur rent. With a constant load current of 500 mA, the up-tracking speeds for switching frequencies of 10 MHz and 30 MHz are 1.67 s/V and 0.67 s/V , respectively. The down-tracking s p e e d sf o r1 0M H za n d3 0M H z are 4.44 s/V and 1.56 s/V , respectively.