This paper demonstrates a high frequency power detector with high conversion gain for frequency-shift sensing applications used in biosensing systems. The proposed design comprises an amplitude-to-voltage convertor (AVC), a peak detector, and a bandgap. To increase the operating frequency range, AVC utilizes half of an RMS power detector to attain the power measure of an input signal. Since the input power is converted to a DC voltage by AVC, the peak detector will secure the resonant frequency when AVC generates the highest voltage. The proposed power detector circuit is realized on silicon using a 60 V 0.25 μm CMOS technology. Measurement results show that the proposed circuit is able to detect input frequency from 500 Hz to 2.5 GHz. The conversion gain of AVC is 166.6 mV/dB, and the power consumption is 5.25 mW given a 5 V power supply voltage.
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