A Design Of Flyback AC-DC Converter Digital Power Management Chip Based On Primary And Secondary Side Integration

AC-DC converters are widely used in the power supply and charging of mobile electronic devices such as smart phones,tablet computers,Bluetooth headsets,and smart wearable devices to provide power to mobile electronic devices.The development trend of the AC-DC converter control chip is higher efficiency,higher energy density and higher level of intelligence.Based on the characteristics of the flyback AC-DC converter,the key technologies of integrated control and digital control are studied in this paper.This paper first analyzes the constant voltage output control scheme of the flyback converter,and proposes that the feedback control of the flyback converter can be split into multiple functionally independent processing modules.The output voltage passes through each processing module in turn and is converted into two control signals:peak current and switching cycle.By analyzing the electrical characteristics of the constant current mode,this paper considers the constant current mode to be a special case of the constant voltage mode and unifies the feedback control into a single control path.Then the paper analyzes the loss source of the flyback converter,and proposes a frequency reduction curve control and quasi-resonant control scheme.The small signal model of the flyback converter is analyzed and the compensator is designed.In order to solve the problem of output sampling accuracy,a high-precision sampling scheme is proposed And this article has carried on the digital treatment to the above several schemes,has deduced the equivalent mathematical expressionThis paper then designed the digital circuit of the flyback converter power management chip,and designed a special secondary-side digital logic programmer for a large number of numerical mathematical operations involved in digital control According to the characteristics of the flyback converter,this paper designs the processor architecture,instruction set architecture,memory,controller,ALU and function modules of the programmer,and designs the program for controlling the flyback converter.Aiming at the signal reception and switch control of the primary side,this paper also designs the primary side digital logic controllerFinally,a power stage prototype is designed in this paper,and the digital control system is verified with FPGA.The test results show that the system can achieve 5V,9V,12V,15V,20V constant voltage output under a wide range of 90?260V AC input conditions,the highest efficiency can reach 93.2%,the load regulation rate is low,and the ripple is less than 2%.