A clamp drive circuit

Abstract

The invention relates to a clamp driving circuit, which includes a bias current source, an accelerating current mirror with a fourth MOS tube, an inverter with a fifth MOS tube, and a totem pole output driver with an upper drive tube , a conversion current mirror, a current mirror switching tube for switching the conversion current mirror, a voltage stabilizing resistance or a constant current source connected between the source and the drain of the fourth MOS transistor; and a A clamp sampling circuit connected between the gate of the upper drive transistor and the ground. The present invention utilizes the clamping sampling circuit and turns off the conversion current mirror through the current mirror switch tube and drives the accelerating current mirror, thereby completely turning off the large driving accelerating current, and realizing high-speed driving by adding a constant voltage maintaining resistance or a constant current source At the same time, the power consumption of the circuit is reduced; at the same time, due to the existence of the voltage stabilizing resistance or the constant current source, there is no instability in the clamping voltage during the establishment process, and the entire circuit has a low degree of dependence on the process.

Description

technical field [0001] The invention relates to a low power consumption clamp driving circuit applied to a switching power supply. Background technique [0002] As we all know, switching power supply technology has been widely used. In a switching power supply, the signal high level used to drive the power switching device generally does not require an excessively high voltage, because the driving loss is proportional to the square of the high-level voltage, and the excessively high driving voltage will make the power switch The selection of components is limited. For this reason, it is necessary to clamp the driving voltage in terms of safety and performance. [0003] At present, commonly used clamp drive circuits such as figure 1 As shown, the circuit is composed of a bias current source 101, an inverter 102, a driving current mirror 103, a clamping diode 111 and a totem pole output driving circuit 104, wherein the inverter 102 includes a first MOS transistor 109 and a ...

AI Technical Summary

Problems solved by technology

The problem with this circuit is that when the input signal IN is at a low level, in order to ensure the rising speed of the driving signal OUT, the driving current of the previous stage must be large enough, which will cause the current flowing through the clamping diode 111 in the clamping state is also very large, resulting in very large power losses

It can be seen that the reliability and stability of the above-mentioned prior art are relatively poor, and the degree of dependence on the manufacturing process is too high

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