A 15-25-MHz and 1-mu s/0.4-A Load Response AOT Boost Converter Using an Accurate Feedforward-Path Current Sensor

Abstract

This letter presents a high-frequency boost converter using an accurate feedforward-path current sensor for the fast-load transient response. To operate with the switching frequency of up to 25 MHz, the proposed current sensor senses the inductor current with a fast-sensing response time of about 4.5 ns. It also provides more accurate sensing gain than previous current sensors. In addition, the adaptive on-time control method is used for the proposed converter to further enhance the transient responses. The converter has been fabricated using a 0.18-mu m CMOS process with a total chip area of 1.3 x 1.12 mm. It achieves a fast-load transient of only 1 mu s at a 400-mA load step, and peak efficiency of 91.5 and 88.2% at switching frequencies of 15 and 25 MHz, respectively.