A Weak Current to Voltage Conversion Circuit Based on Resonant Amplifiers and Crystal Filters

The accurate detection of weak current signal plays an important role in academic, industrial, daily life, and other fields. However, the weak current signals of nano-ampere levels are easily affected by sensor noise, electronic device noise, and others, which makes the precise detection of weak current signal become critical issues. Based on these challenges, to improve the detection ability of weak current signal at a specific frequency band, this paper proposes a current-voltage conversion circuit based on resonant amplifiers and a crystal filter. The resonant amplifiers convert and amplify the weak current signal, firstly. Moreover, a crystal filter is used to further compress and filter the noise and harmonics in a weak current signal. Practical test results show that this proposed weak current conversion circuit has good performance that the maximum spurious-free dynamic range improvement can be 73.9dB.