A simple structure AGC for synchronous capacitor resonant converter used in HIFU application

In this paper, an automatic gain control amplifier (AGC) is proposed. The proposed AGC aims at a large input and output swing with a rapid tracking capacity. Moreover, the proposed AGC has a quite simple structure, which is very important for High intensity focused ultrasound (HIFU) applications in which an array of identical circuits must be used. The designed circuit was simulated in a CMOS 0.35μm technology. The required performances have been confirmed by simulation results: a large ratio of input signal of 20 has been achieved; a good linearity with a relative error lower than 0.62% is observed; the output peak-to-peak signal can be as high as 2V; the tracking time is less than 6μs, for an input signal of 1MHz.