Switch driving circuit of dcdc converter

Abstract

The invention provides a switch drive circuit of a DCDC converter, comprising a control signal generation module for generating a control signal which is logically consistent with an input signal; wherein the first PMOS tube, the second PMOS tube and the first NMOS tube are connected in series between a power supply and the ground, grid electrodes of the first NMOS tube and the second PMOS tube are respectively connected with an input signal and a control signal, and drain electrodes of the first NMOS tube and the second PMOS tube output driving control signals; the third PMOS transistor and the second NMOS transistor are connected in series between the drain electrode of the first PMOS transistor and the ground, the grid electrodes of the third PMOS transistor and the second NMOS transistor are connected with a control signal, and the drain electrodes of the third PMOS transistor and the second NMOS transistor are connected with the grid electrode of the first PMOS transistor; the fourth PMOS transistor and the third NMOS transistor are connected in series between a power supply and the ground, the grid electrodes of the fourth PMOS transistor and the third NMOS transistor are connected with an input signal, and the drain electrodes of the fourth PMOS transistor and the third NMOS transistor are connected with the drain electrode of the first PMOS transistor through the firstcapacitor. The bootstrap capacitor and the drive circuit are combined, the capacitance value and the area of the bootstrap capacitor can be reduced to one thousandth to one thousandth of the traditional numerical value, the built-in bootstrap capacitor is realized, and the application scheme is simplified.

Description

technical field [0001] The invention relates to the technical field of integrated circuits, in particular to a switch driving circuit of a DCDC converter. Background technique [0002] The DC / DC converter is a switching power supply chip, which uses the energy storage characteristics of capacitors and inductors to perform high-frequency switching actions through controllable switches (MOSFETs, etc.), and stores the input electric energy in capacitors (inductors). When it is turned on, the electric energy is released to the load to provide energy. Its output power or voltage capability is related to the duty cycle (the ratio of the switch on time to the entire switch cycle). Switching power supplies can be used for step-up and step-down. [0003] Step-down DCDC uses NMOS tube as the main power switch tube, such as figure 1 As shown, wherein, the PMOS transistor PM1 and the NMOS transistor NM2 are used as the output stage of the drive circuit, the drains of the PMOS transis...

AI Technical Summary

Problems solved by technology

[0005] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a switch drive circuit for a DCDC converter, which is used to solve the problems of complex application schemes and high costs of the drive circuit in the prior art.

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