Design Of High-frequency Switching Power Supply Based On The Multiple Modules In Parallel

With the development of modern society,people become increasingly dependment onelectronic devices,and various power supply are the important equipment.But the daily linearpower supply are of low efficiency and large power consumption,big volume,which restrctsthe application of the electronic equipment.But the switching power supply dosen’t have thesedisadvantages.It has high efficiency and low energy consumption.Moreover with increasingswitching frequency,switching power supply is getting smaller and smaller.So,people have toface the problem that how to increase the frequency and improve the efficiency.In this paper,we select the SG3525which is a production as a power supply module,whichuses PWM control mode to control the opening and closing of the switch to control the dutycycle in order to control the output of the high frequency transformer.SG3525is ofcurrent-controlled PWM controller,which can adjust the duty cycle according with thefeedback current.It can output two signals to control the two signals swtich off,and it has largeoutput current which can can directly drives the MOS or IGBT. According with the feedbackof the output current and voltage, the SG3525can control the output of the high frequencytransformer, thus achieving a stable voltage and stable current. We use the LM324to builtPID to adjust the output voltage or current through changing the input voltage or current.On the other hand,with the development of electronic technology,people increase the highdemand on the power supply output power.But lots of conditions restrict the large poweroutput,such as the parameters and magnetic device function and other conditions.So multiplemodules in parallel is the research direction,There are four main mode in module power ofparallel:the droop law, the master slave law, the average of current law and the maximum ofcurrent low.In this paper we first introduce the circuit diagram and working principle of thefour methods.After analyzing the advantages and disadvantages of four methods,we choosethe maximum of current law.Then we introduce the functionality and the external circuit ofUC3902.Then we explain the course of its work through the introduction of the peripheralcircuits of the chip. This desing is mainly directed against a number of experimental power supply moduledesign,wishing to provide a certain reference value for the recerching on the high powermidule power supply.