摘要
Purpose At present,the high-energy photon source(HEPS)is under construction in Beijing.HEPS has beam emittance lower than 40 pm rad.In order to ensure low beam emittance,a high-performance fast orbit feedback system(FOFB)is designed for fast and accurate correction of beam orbit.The FOFB needs to have the smallest adjustment step.Therefore,as the execution unit of the FOFB system,the output current resolution of the fast corrector power supply needs to be as small as possible.In FOFB systems,precise correction of beam orbit is required for fast corrector power supply with output current resolution better than 60μA.A precision digital sampling system needs to be designed to meet the high requirements of output current resolution.Method The precision operational amplifier is used to complete the scaling and sampling of signals.The precision operational amplifier is used as the front-end processing in the circuit design to complete the amplitude processing and filtering.Meanwhile,the precision operational amplifier is used as the driver of the precision analog to digital converter(ADC)chip.A precision ADC chips based on oversampling technology is used.With this scheme,the selected ADC chip can have the advantages of both high speed and high precision.A simulation prototype is built for test,and the performance parameters of key chips in the design are given.Results A precision voltage reference is used to test the designed digital sampling system.The test results showed that the acquisition system has an effective resolution of 21.6 bits.The HEPS fast corrector power supply is used for testing the developed precision sampling system.The test result showed that the output current resolution of fast corrector power supply is lower than 16μA.
