nmos power transistor gate drive module, drive circuit and switching power supply

Abstract

The invention provides an NMOS power tube gate drive module, a drive circuit and a switching power supply, and relates to the technical field of switching power supplies. The NMOS power tube gate drive module is realized by a transistor integrated circuit process. The NMOS power transistor grid drive module has a simple internal circuit and is suitable for switching power supply drive circuits and boosted switching power supplies. By quickly turning on and off the NMOS power tube, it solves the problem of large turn-on and turn-off losses of the NMOS power tube used in the switching power supply chip, and has its own over-current detection function, which has the advantages of simple structure, low cost, and high reliability.

Description

technical field [0001] The invention relates to the technical field of switching power supplies, in particular to an NMOS power tube gate driving module, a driving circuit and a switching power supply. Background technique [0002] There are two types of power transistors inside the switching power supply chip: power transistors and power MOS transistors. Power MOS transistors are further divided into PMOS power transistors and NMOS power transistors. For boost chips, PMOS transistors are selected as the control circuit of the switching transistor and NMOS transistors are selected. The control circuit of the tube as a switch tube is completely different. [0003] Different types of power MOS transistors have different internal majority carriers when they work. Compared with PMOS power transistors, the on-resistance Rdson of NMOS power transistors is smaller under the same unit area. In the case of the same on-resistance Rdson, the NMOS power transistor has a smaller inter-e...

AI Technical Summary

Problems solved by technology

[0004] When an NMOS power tube is used as a power switch tube in a switching power supply chip, the drive circuit of the NMOS power tube often needs to add an external BOOST capacitor to provide a stable power supply for the drive circuit, and a corresponding capacitor charging circuit, level shifting circuit and Drive circuit, the internal circuit structure is complex

Moreover, in the prior art, overcurrent detection usually realizes overcurrent protection by sampling part of the power tube current and calculating the current value of the entire chip power tube through proportional conversion. The problem of poor current accuracy

Images