Design And Realization Of Readout Control Unit In X-ray Detector

Since the discovery of X-ray pulsars,scientists have not been satisfied with only observing them.With the deepening of research,they proposed to use pulsars for positioning of artificial satellites and autonomous navigation of aircraft in deep space.With the continuous demand on the application level,the performance of current pulsar detectors can no longer meet the requirements,so the research on high-speed,high-precision,low-noise,and multi-functional X-ray detectors has become an important research direction in the subject of pulsar detection.Based on the current external demand for X-ray detectors,this paper firstly designs the readout chip in the detector at the system level,and establishes the chip’s readout method based on event-triggered drive: when a single pixel detects a particle hitting event,Firstly,the hit on the pixel is converted into the hit on the column where the pixel is located,and then the readout of the column is converted into the readout of the hit pixel in the column during readout.Through this processing method,the expansibility of the detector chip is better and the readout speed is faster.The detector readout chip performs functional configuration and readout of the address of the hit pixel through the readout control unit.A hit sequence arbitration algorithm is designed in the readout control unit.In addition to address output in the order of pixel hits,it also realizes high-precision,high-speed readout with a resolution accuracy of less than 1μs for different hit events,and a single pixel with less than 1μs time from being hit to readout.In order to improve the measurability and lifetime of the X-ray detector,the readout control unit supports the function of configuring the working mode of each pixel through the I2 C interface.In addition to the normal X-ray particle detection mode,the readout control unit can set the pixel to the masking mode and the self-test mode,and cooperate with the software program to realize the timing self-test and dead pixel masking of the pixel array.And users can configure the current and voltage DAC registers in the readout chip through the I2 C interface to facilitate the measurement and adjustment of the chip.The readout control unit uses Verilog HDL language to implement parameterized RTL,so that the readout control unit can support readout and control of pixel arrays of any size.A simulation model of the pixel array is constructed,and the long-term digital-analog hybrid simulation is replaced by the functional simulation of the model and the readout control unit.Afterwards,GSMC 0.13μm process is used to realize the back-end physical realization of the readout control unit under the 40×50 array.The generated readout control unit layout size is2800μm×300μm,and the overall layout area of the readout chip is5000μm×5000μm.After tape out,a dedicated test platform was designed for this detector chip,which can accurately collect the digital and analog output of the chip and transmit it to a personal computer for data analysis.Corresponding host computer program has also been developed,which can configure the pixel array of the readout chip for masking and self-testing,and complete the noise consistency test.