Based On The CZT Detector Signal Acquisition Circuit Research And Design

At first,this paper analyzed the working principle of tellurium cadmium zinc detector and the characteristics of the output signal,and studied how to reduce the influence of the detector leakage current and the distributed capacitance to the readout circuit noise and the output baseline.In the circuit,the leakage current compensation circuit is adopted in the core parts of the readout circuit and the MOS capacitors and the structure of CMOS virtual resistance.A problem of zero-pole point is analyzed for the output of Pre amplifier,and designed a zero pole cancellation circuit;Through the low noise design technology and fourth order plastic shaping circuit,a quasi gaussian waveform with one microsecond forming time and 350 nanoseconds tmax and the stable readout circuit of baseline in 590 mV is obtained finally.For the readout circuit must adapt to 40 to 100 degrees Celsius temperature environment,this paper analyzes the principle and the performance influence factors of bandgap reference source,and design a bandgap reference with op-amp.As for the compensation current as small as nA,analyzing and comparing the three CMOS current sources with good stability and high precision which adopt the sum of compensation instead of temperature coefficient of current solutions,convert make zero temperature coefficient of voltage into a current solution and the bias-self current source.A bias-self current source with temperature compensation,is designed on the basis of the bias current source which is nothing to do with the power supply voltage.A 3V working voltage for the core circuit,this paper designed a linear regulator circuit with 130 db power supply rejection ratio,and the circuit can output 3V voltage stability when the power supply voltage is greater than 5V.