Design Of A New Single-chip Isolated Power Supply With High Frequency Rectification

With the advent of the information age of the Internet of Everything,"smart+" has begun to be mentioned more and more.In particular,the promotion of 5G communication technology has made people enjoy the smoother information civilization.The highfrequency digital communication system behind it relies on good electrical isolation to meet the integrity and stability of information transmission.Isolated power supplies are widely used in electronic communication systems or industrial monitoring instruments because they provide both power transfer and digital signal isolation.The isolated power supply based on the coreless micro-film chip transformer has the advantages of good isolation performance,high magnetic immunity,small size,and monolithic integration,and is a good solution for realizing single-chip integration of the power supply system and the digital isolator.At the same time,the contradiction between cost and efficiency of low-voltage,low-power power solutions makes the study of new single-chip isolated power supplies very important.This topic mainly studies and designs a new type of high-frequency rectified monolithic isolated power supply,which has higher power conversion efficiency than the traditional isolated power supply structure.The Class-C oscillator is used to generate an 191 MHz AC signal at the original end,which is transmitted to the secondary terminal through the coreless micro-transformer,and then stabilized by the full-wave rectifier circuit and the voltage feedback loop to achieve a stable DC output voltage.The pulse width modulated signal drives the tail current transistor in the oscillator circuit to achieve control over the power transfer duration.At the same time,the circuit can select the output voltage to be 3.3V or 5V through the external port,and the output has very small voltage ripple and current ripple.In both output states,the power supply can provide output power greater than 400 mW.The paper firstly gives a brief overview of the isolated power supply,introduces its development trend,and then proposes the system structure of the designed single-chip isolated power supply based on the electromagnetic coupling technology.Focus on the working principle of Class-C oscillator,coreless micro-transformer and CMOS full-wave rectifier,and design the main function part that satisfies the performance index.On the basis of the design of the peripheral basic module,the 0.35?m BCD process of a certain manufacturer is selected,and the performance of the whole system is verified by EDA software.Finally,in a wide range where the load current remains greater than 30 mA,when the input/output voltage is 3.3V,and the power conversion efficiency is about 36%;the input/output voltage is 5V,and it has a power conversion efficiency of around 39%.The power conversion efficiency is about 5% higher than that of similar circuits,when the load current is greater than 100 mA.