Switch tube driving circuit of bridge switching topology

Abstract

A switching tube driving circuit of a bridge type switching topology comprises upper bridge switching tube driving modules, lower bridge switching tube driving modules and lower bridge overcurrent protective modules. Each upper bridge switching tube driving module is used for outputting an upper bridge driving voltage to a gate of a corresponding upper bridge IGBT Q1 according to a gate driving signal of a controller. Each lower bridge switching tube driving module is used for outputting a lower bridge driving voltage to a gate of a corresponding lower bridge IGBT according to the gate driving signal of the controller. The upper bridge driving voltages of all the upper bridge switching tube driving modules are the same, the lower bridge driving voltages of all the lower bridge switching tube driving modules are the same, and the upper bridge driving voltages are larger than the lower bridge driving voltages. Each lower bridge overcurrent protective module is used for detecting the voltage Vce between a collector electrode and a transmitting electrode of one corresponding lower bridge IGBT when the corresponding lower bridge IGBT is switched on and comparing the voltage Vce with a preset threshold voltage. Compared with the prior art, a half of the overcurrent protective modules can be omitted, the driving circuit is greatly simplified, and it is ensured that circuit overcurrent detection is accurate and reliable.

Description

technical field [0001] The invention relates to a switch tube drive circuit of bridge switch topology. Background technique [0002] Due to its low conduction loss, small driving power and fast switching characteristics, IGBT switching tube devices are widely used in frequency converters, inverters and switching power supplies, etc., and realize the power conversion function in bridge switching topology. [0003] Such as figure 1 As shown, the inverter includes an upper-bridge IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor) K1, an upper-bridge IGBT K2, a lower-bridge IGBT K3, a lower-bridge IGBT K4, and a switch tube drive circuit (not shown). The switching tube drive circuit includes four IGBT drive modules for respectively outputting gate drive voltages Vg1 to Vg4 to IGBTs K1 to K4, and four IGBT overcurrent protection modules for respectively. The gate drive voltages Vg1 to Vg4 are all equal. When overcurrent occurs, since the currents flowin...

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Problems solved by technology

If the upper bridge IGBT is desaturated, the overcurrent protection module of the lower bridge IGBT will not be able to collect the overcurrent signal. Therefore, the drive circuit of the existing bridge switch topology often needs to set an overcurrent protection module for each IGBT. ,E.g figure 1 The IGBTs K1 to K4 in the shown inverter will need to be respectively equipped with four overcurrent protection modules, which increases the complexity of the driving circuit of the bridge switching topology and increases the production cost

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