A preamplifier includes a single-ended amplifier, a differential amplifier, an operational amplifier, and a clipping circuit. The single-ended amplifier converts an input current signal into a voltage signal, outputs an amplified voltage signal according to a preset amplification gain. The differential amplifier includes first and second differential inputs, and outputs a negative-phase signal and a positive-phase signal. The amplified voltage signal is applied to the first differential input of the differential amplifier. The operational amplifier includes first and second inputs which respectively receive the negative-phase signal and the positive-phase signal, where an output of the operational amplifier is applied to the second differential input of the differential amplifier. The clipping circuit clips an amplitude of the negative-phase signal output by the differential amplifier.