Driving control method and circuit thereof

Abstract

The invention discloses a driving control method and a circuit thereof. A rising edge of an input signal is modulated into a positive pulse with a fixed pulse width through an edge modulation circuit,a falling edge of the input signal is modulated into a negative pulse with a fixed pulse width, a plurality of continuous positive pulses are generated at a certain period in a state that the input signal is at a continuous high level, and the period is adjustable; positive and negative pulses generated by the edge modulation circuit are transmitted to the secondary side from the primary side inan isolation mode through the isolation transformer; a first positive pulse generated by the secondary side of the isolation transformer is demodulated into a rising edge of a driving signal through adriving holding circuit; a plurality of continuous positive pulses generated by the secondary side of the isolation transformer are demodulated to continuously supplement energy to the driven power tube so as to maintain the driving voltage, and negative pulses generated by the secondary side of the isolation transformer are demodulated to the falling edge of the driving signal so as to restore the input signal. The driving control method and the circuit thereof can achieve the purpose of isolation drive and have a normally open function of keeping continuous conduction of the MOS transistor.

Description

technical field [0001] The invention relates to the technical field of switching power supplies, in particular to a driving control method and circuit for a power switching device capable of realizing continuous conduction using transformer isolation. Background technique [0002] Compared with linear power supplies, switching power supplies have the characteristics of small size, high efficiency, and high power. They are widely used in the fields of automobiles, photovoltaics, industrial control, medical and handheld devices. It has superior performance at high frequencies, so it is used as a power switching device in the switching power supply. This type of device has a capacitor gate-controlled input terminal and is a voltage-controlled power semiconductor. Usually, a certain voltage is added to the gate and source. voltage, it can be turned on, and zero voltage or a certain negative voltage can be applied to turn it off. [0003] Switching power supplies have different ...

AI Technical Summary

Problems solved by technology

[0007] With the continuous development of switching power supply technology, the requirements for its cost and volume are becoming more and more stringent. The reduction in volume is inseparable from the increase in frequency, and the reduction in cost is closely related to the reduction in devices. In order to cope with the increase in frequency The loss increases and the number of switching power supplies is reduced. Multi-mode switching circuit structures and more complex soft-switching control strategies are constantly being proposed. In multi-mode switching power supplies and complex control strategies, the power circuit adjusts the working state according to different working conditions. Under different working conditions, the power device will be turned on briefly and continuously. Usually, a resistor of about 10k will be connected between the gate and the source of the power switch tube, resulting in the publication number CN110311572A " A Transformer Isolation Drive Control Method and Its Isolation Drive Circuit" The scheme in the patent application cannot achieve continuous conduction

The bootstrap solution in the existing solutions mainly relies on the conduction of the lower tube to supplement energy for the bootstrap capacitor. Therefore, when the upper tube needs to be continuously turned on, the lower tube must be continuously turned off and cannot charge the bootstrap capacitor. The bootstrap capacitor can't keep the upper tube continuously turned on

Existing transformer isolation schemes rely on transformers to transmit switching signals. As we all know, transformers can only transmit AC signals, but cannot transmit DC signals. Therefore, when the drive needs to be continuously turned on, the transformer isolation scheme cannot continuously provide the voltage and energy required for turning on.

In summary, the other two power device drive solutions cannot achieve continuous conduction of power devices

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