© The Institution of Engineering and Technology
A sense-FET-based inductor current sensor for a buck converter operating in 10 MHz switching frequency is reported in this Letter. The proposed sensor utilises an adaptive gm -boosting amplifier to maintain stable current sensing loop gain and bandwidth over a wide range of load current. Moreover, a mirrored source-degeneration output stage is introduced to further eliminate the bandwidth variation by loading change and achieves full-wave current sensing with smooth transition between the sensed peak and valley currents as the inductor is energised and de-energised. Simulation results show high sensing accuracy better than 96.8% with inductor current varying from 200 mA to 2 A. Furthermore, the settling time is <6 ns during the state transition between peak and valley current sensing with low-voltage spikes.
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