MOSFET/IGBT high-speed driving circuit based on linear optical coupling isolation

Abstract

The invention discloses an MOSFET / IGBT high-speed driving circuit based on linear optical coupling isolation. The high-speed driving circuit utilizes a variable resistance structural circuit on a collector or an emitter of a linear optical coupler and adopts a dynamic voltage comparing circuit on an output loop of the optical coupler, so that the transmission speed of a driving signal and the gradient of a rising and falling edge are improved, and thus the performance of the driving circuit is improved. The high-speed driving circuit has the advantages of fast high-speed driving speed, small volume and the like.

Description

technical field [0001] The invention relates to a MOSFET / IGBT drive technology, in particular to a MOSFET / IGBT high-speed drive circuit based on linear optocoupler isolation. Background technique [0002] The drive circuit is the bridge connecting the control circuit and the main power electronic device, and converts the control signal into a waveform and voltage suitable for the direct control input of the power electronic device. At the same time, since the main circuit of the power electronic device is a large current and high voltage, while the control circuit is a low current and low voltage, in order to avoid the interference or damage of the main circuit to the control circuit, the two need to be electrically isolated, and the driving circuit is exactly the complete This isolates the tasks of the link. [0003] For general power electronic device drive circuits, two basic functions are required, one is to have an isolation function, and the other is to perform wavefo...

AI Technical Summary

Problems solved by technology

[0004] At present, the main problem of MOSFET / IGBT drive circuit is that the operating frequency is not high, whether it is a magnetic isolation drive circuit using a high frequency transformer or an integrated drive circuit using optocoupler isolation The highest measured operating frequency of the circuit is around 100kHz. If the frequency of the driving signal is further increased, the output waveform will be abnormal, and the power electronic system will not work normally.

[0005] When using discrete components to form an optically isolated drive circuit, the optocoupler is the key component of the drive circuit; if a switch-type optocoupler is used, the operating frequency of the high-frequency switch-type optocoupler can reach several MHz, which can meet the requirements, but the operating voltage is generally 5V, and the working voltage of the driving circuit is 12V and above, the level is not compatible; if a linear optocoupler is used, the linear optocoupler can work normally at a voltage of 12V and above, but the operating frequency is generally tens of kHz, which cannot meet the requirements high frequency requirements

Therefore, neither the integrated MOSFET / IGBT drive circuit nor the discrete element MOSFET / IGBT drive circuit can meet the needs of high-speed drive at present.

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