Abstract: A CMOS peak detection circuit using differential operational amplifier with current mirror is presented,including input signal peak voltage detector and over-peak discriminator.The circuit design is based on 0.5μm CMOS technology,achieving the detection for quasi-Gaussian signal,the range of which peak voltage is 0~5V and the peaking time is 1~5μs,error is less than 6mV.Another improvement is for over-peak discriminator,using first differential then compared with zero in order to avoid one quasi-Gaussian multiple peak voltage output.