A broadband frequency-to-voltage converter is designed to operate at the multi-GHz frequency band. The circuit detects the input signal frequency and generates a DC output voltage correspondingly, regardless of the input power variation through a two-path signal process of frequency discrimination and signal power reference. One advantage of the design utilizing power detection makes the method feasible for very high frequency applications. The integrated design is verified in an integrated system mixed with off-the-shelf commercial components. Measurement results show a maximum output voltage RMS error of 2.1 % over the input frequency from 1 GHz to 4 GHz with the input power level -30 dBm to 0 dBm.