Clamp drive circuit

Abstract

The invention relates to a clamp drive circuit which comprises a bias current source, an acceleration current mirror with a fourth MOS (metal oxide semiconductor) tube, a phase inverter with a fifth MOS tube, a totem-pole output driver with an upper drive tube, a conversion current mirror, a current mirror switch tube used for switching on and off the conversion current mirror, a stable voltage maintaining resistor or a constant current source connected between the source and the drain of the fourth MOS tube, and a clamp sampling circuit connected between the grid of the drive tube and the ground. According to the clamp drive circuit, the conversion current mirror is switched off and the acceleration current mirror is driven through the current mirror switch tube by the clamp sampling circuit so as to completely switch off high drive acceleration current; by adding the stable voltage maintaining resistor or the constant current source, the circuit consumption is reduced while high-speed drive is realized; meanwhile, due to the existence of the stable voltage maintaining resistor or the constant current source, the clamp voltage is stable in the establishment process, and the dependency degree of the whole circuit to a process is low.

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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