Bootstrap circuit for driving high-side NMOS (N-channel metal oxide semiconductor) tube

Abstract

The invention discloses a bootstrap circuit for driving a high-side NMOS (N-channel metal oxide semiconductor) tube, which belongs to the field of power management, and is characterized in that bootstrap voltage VBOOT higher than VIN is generated on the basis of power voltage VIN and used for driving the NMOS tube, and the bootstrap circuit for driving the high-side NMOS tube comprises a level shift circuit, a driving logic circuit, a driving tube module and a bootstrap module; the level shift circuit converts a low-voltage power domain control input signal into a high-voltage power domain output control signal; the driving logic circuit comprises a high-side driving logic circuit and a low-side driving logic circuit which are respectively used for controlling the on and off states of a high-side driving tube and a low-side driving tube; the driving tube module comprises a high-side driving tube and a low-side driving tube and provides load current for a rear-end circuit; and the bootstrap module generates a high-voltage power domain and provides a power supply for the level shift circuit and the high-side driving logic circuit so as to control the high-side driving tube.

Description

technical field [0001] The invention relates to the technical field of power management, in particular to a bootstrap circuit for driving a high-side NMOS transistor. Background technique [0002] In power management systems, especially in traditional synchronous step-down DCDC chips, most of the high-side drive tubes use PMOS tubes instead of NMOS tubes. Because the turn-on threshold voltage VTH of NMOS tubes is positive, if the traditional synchronous step-down If the high-side PMOS drive tube in the pressure-type DCDC chip is replaced by an NMOS drive tube, it is necessary to generate a voltage higher than the power supply voltage VIN in the circuit to drive the NMOS tube, but this will inevitably introduce a large number of circuits with complex structures and increase the number of chips. Therefore, most of the high-side drive tubes in traditional synchronous step-down DCDC chips use PMOS tubes, which greatly limits the application of high-side drive tubes using NMOS tu...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a bootstrap circuit for driving high-side NMOS tubes, so as to solve the problem that it is difficult to generate a voltage higher than the power supply voltage VIN in a traditional synchronous step-down DCDC, which causes the N-type drive tube to be used in a synchronous step-down DCDC chip. Issues with limited use

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