A current-to-voltage converter comprises a gain circuit, a flip circuit, and a chopper circuit. The gain circuit receives an input current, and amplifies the input current to generate an amplified current. The flip circuit receives the amplified current, and uses the amplified current to charge or discharge a capacitor thereof according to a charge signal and a discharge signal, so as to generate an output voltage, wherein before using the amplified current to charge or discharge the capacitor, the flip circuit resets the output voltage respectively to a charge reset voltage and a discharge reset voltage according to a charge reset signal and a discharge reset signal. When the capacitor is charged, the chopper circuit samples and holds the output voltage to generate a recovered voltage. When the capacitor is discharged, the chopper circuit samples, holds, and flips the output voltage to generate the recovered voltage.