Integrated current-mode DC–DC boost converter with high-performance control circuit

Abstract

In this paper, integrated BiCMOS amplifier and current-sensing circuits are introduced for high-performance DC---DC boost converter. By exploiting the advantage of BiCMOS technology, the high gain amplifier and accurately sensed inductor current are obtained in the feedback control circuit. The proposed current-sensing circuit adopts a current-mirror instead of op-amplifier as a voltage follower so that it would reduce power consumption with a smaller chip-size. Bipolar transistor is also applied in the differential pair and current sources of the error amplifier to obtain a fast transient response. Frequency response shows the amplifier gain with the compensator affects significantly on the stability of the converter. The chip is fabricated in 0.35 µm 2-poly 4-metal BiCMOS process. The measurement shows that the current-sensing circuit can operate with accuracy of higher than 90 % at the frequency from 10 to 200 kHz and the transient time of the error amplifier is controlled within 10 µs. The converter with chip-size of 1 mm2 operates at the output voltage of 4.5---9 V with the frequency of 0.01---1 MHz.