A Power Switch Tube Isolation Barrier Drive Circuit Generating Fixed Negative Pressure

Abstract

A power switch tube isolation barrier drive circuit for generating a fixed negative voltage, including a pulse width modulation driver, capacitors Cb, C1, transformer T1, diode D and switch tube Q1. Add resistor R1 in parallel with capacitor C1, capacitor C2 in parallel with resistor R2 and Buck circuit, auxiliary transformers TA, TB. TB has two secondary sides, C2 and R2 are connected in parallel, and one end is connected to the cathode of diode D, and the other end is connected to the gate of Q1 through one of the secondary sides of TB, and the positive output terminal of the Buck circuit is connected in series with the two primary sides of TB and TA Then connect to the negative output terminal of the Buck circuit, connect the non-identical terminal of the primary side of T1 and ground with the same-named terminal of the primary side of T1 in series with the secondary side of TA and the other secondary side of TB. When Q1 is turned off, diode D, capacitor C2, and resistor R2 form a negative voltage generating source, and Buck circuit, auxiliary transformer TA and TB form a voltage compensation network to ensure the stability of negative voltage and avoid false conduction of Q1.

Description

technical field [0001] The invention relates to a power converter in the switch circuit technology, in particular to a power switch tube isolation grid drive circuit for generating a fixed negative pressure. Background technique [0002] Modern electronic equipment puts forward requirements on lightness and high efficiency for its power supply device (power converter), which makes the power density and switching frequency of the power converter continue to increase, the bridge topology with larger power capacity, and the new type of power converter with better performance Devices such as insulated gate field effect transistors (IGBTs) are widely used. Due to material limitations, traditional silicon-based power devices have approached or even reached the intrinsic limit of their materials in many aspects, and wide bandgap devices such as silicon carbide (SiC) and gallium nitride (GaN) have emerged. All of these put forward higher requirements such as faster, more efficient,...

AI Technical Summary

Problems solved by technology

But this magnetic isolation drive circuit also has obvious disadvantages, the isolation drive transformer T 1 Due to the influence of the winding process, a certain leakage inductance will be generated. This leakage inductance will resonate with the DC blocking capacitor at the moment of turn-on and turn-off, and eventually cause a certain voltage spike to be superimposed on the output level of the drive circuit. The voltage spike may cause power The malfunction of the switch tube makes the control invalid

Not only that, the excessive resonance voltage spike caused by the leakage inductance will also cause the gate of the power tube to be broken down. For the wide bandgap device that is easier to be broken down, it is especially necessary to have a negative voltage on the gate when the device is turned off.

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