Self-excitation driving and power conversion circuit based on GaN HEMT device

Abstract

The invention discloses a self-excitation driving and power conversion circuit based on a GaN HEMT device. The self-excitation driving and power conversion circuit adopts the novel GaN-based HEMT device, and improves the working frequency of the circuit to MHz. The device adopts a silicon substrate, and adopts on-chip design of a Q1 transistor and a Q2 transistor, wherein the two transistors share one wafer, so that the size is reduced, the cost is reduced, and the reliability control is improved. The device further adopts an integrated anti-parallel diode structure, so that the reverse conduction characteristic of the device is improved. According to the self-excitation driving and power conversion circuit, through using a third auxiliary winding Na in a main transformer of a power circuit, a self-excitation driving cavity in a positive feedback mode is adopted to automatically provide a driving signal for Q1, a control chip is not needed, and the driving of the Q1 needs to be ensured to be reliable through a special driving buffer circuit for the GaN HEMT device. The self-excitation driving and power conversion circuit further adopts an integrated high-frequency current cycle-by-cycle detection scheme, and shares one coil with the self-excitation driving cavity, so that a current detection resistor is omitted, and lossless current detection is realized.

Description

technical field [0001] The invention relates to a self-excited drive and power conversion circuit based on GaNHEMT devices. Background technique [0002] With the rapid development of science and technology and the response to the national low energy consumption strategy, the switching power supply market is showing a trend of continuous growth year by year, and the switching power supply field has higher and higher requirements for efficiency and size. Due to the simple structure, few components, high reliability, and low cost of the flyback converter, coupled with the use of inductive energy storage, the primary current is often large, the transformer leakage inductance is large, and its maximum duty cycle is usually limited Within 0.4, the maximum power of the flyback circuit is greatly limited. Therefore, in the case of low power less than 75W, the flyback converter has developed into a dominant position in the market. There is a special circuit form in the flyback conv...

AI Technical Summary

Problems solved by technology

The disadvantage is that due to the large junction capacitance of the traditional Si-based MOS tube, after weighing loss, cost, EMI and other factors, its operating frequency is generally only between 30kHz-100kHz, which is not conducive to improving the power density of the product

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