Magnetic isolation drive circuit

Abstract

The present invention discloses a magnetic isolation drive circuit, comprising a first input end, a second input end, a first output end, a second output end, a switch tube Q10, a diode D10, a TVS diode, a transformer B, a primary winding, a secondary winding, and an acceleration switch-off circuit at the secondary side, wherein the acceleration switch-off circuit includes at least one switch tubeQ11, the positive electrode of the TVS diode is connected to the first input end, the negative electrode of the TVS diode is connected to the negative electrode of the diode D10, the positive electrode of the diode D10 is connected to a drain electrode of the switch tube Q10, and a source electrode of the switch tube Q10 is connected to the second input end, and two ends of the primary winding are respectively connected to the first input end and the second input end. In first few cycles of the circuit, when a primary side MOS transistor is turned off, a primary voltage of the transformer isclamped to a set value by the TVS, and the secondary side can generate a sufficiently large induced voltage and a reverse current to drive operation of the acceleration switch-off circuit, to achievea fast switch-off of a driven power switch component, so that the circuit is no longer out of control in the first few cycles.

Description

technical field [0001] The invention relates to a driving circuit of a power switching device, in particular to a magnetic isolation driving circuit of a power switching device. Background technique [0002] Power switching devices occupy a core position in power electronic devices, and their reliable operation is the basis for the normal operation of the entire device. The driving circuit of the power switching device is the interface between the main circuit and the control circuit, and is an important part of the power electronic device. It has a great influence on the performance of the whole device, and its function is to amplify the driving pulse signal output by the control circuit enough to drive the power switching device and perform necessary isolation. In short, the basic task of the drive circuit is to convert the drive pulse signal from the control circuit into a signal that can be added between the control terminal of the power switching device and the outflow...

AI Technical Summary

Problems solved by technology

The delayed turn-off of the bipolar transistor Q1 leads to the untimely turn-on of the driven MOS tube, which is an important shortcoming of this type of circuit

and Figure 1-4 When the positive driving pulse signal of the next cycle comes, the input capacitance of the P-channel field effect transistor Q2 must be discharged through R5 before it can exit the saturation zone. After Q2 exits the saturation zone, the MOS tubes connected to the C and D terminals Or the IGBT will be turned on. During this period, due to the small voltage drop of D2, the induced voltage of Ns1 is short-circuited through D2, R6 and R7, and the energy consumption is large.

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