NMOS high-side driving circuit

Abstract

The invention relates to an NMOS high-side driving circuit, in particular to an NMOS high-side driving circuit which comprises a microcontroller and is used for controlling on and off of a direct-current power supply. The circuit comprises a microcontroller circuit, a photoelectric isolation circuit, a boost drive circuit, an NMOS tube, an auxiliary power supply circuit, a controlled DC power supply and a controlled load or an electric device. In the control, the NMOS tube is equivalent to a power switch, the saturated conduction of the NMOS tube is equivalent to the switching-on of the switch, the switching-off of the NMOS tube is equivalent to the switching-off of the switch, and the saturated conduction of the NMOS tube generally requires that the gate potential is higher than the source potential by 4V or even more than 10V, but in the prior art, a special driving chip or a boosting transformer generally needs to be used for providing the driving voltage. The microcontroller and common resistors, capacitors and other low-cost components contained in the system are utilized to generate the driving voltage required by NMOS high-side driving. The NMOS high-side driving circuit hasthe characteristics of simple circuit and easiness in implementation, the complexity of circuit design can be reduced, and the cost performance of a product is improved.

Description

technical field [0001] The invention relates to an NMOS high-side drive circuit, in particular to an NMOS high-side drive circuit with a microcontroller for on-off control of a DC power supply. Background technique [0002] In electronic devices containing microcontrollers, it is often necessary to switch on and off the DC power supply for the controlled system through key operations. In order to realize the on-off control of the DC power supply of the controlled system, the circuit structure in which the drain of the NMOS transistor is connected to the power supply and the source is connected to the power supply end of the controlled system is often used, which is the so-called NMOS high-side drive circuit. In this control, the NMOS tube is equivalent to the power switch, the saturated conduction of the NMOS tube is equivalent to the closing of the switch, and the cut-off of the NMOS tube is equivalent to the opening of the switch. Generally, the saturated conduction of the...

AI Technical Summary

Problems solved by technology

In the on and off control of this kind of DC power supply, the NMOS tube needs to be kept in a saturated conduction state for a long time. Capacitor bootstrap boost to provide the drive voltage

The DC driving voltage of the existing NMOS high-side drive circuit used for system DC power on and off control is mostly generated by a dedicated NMOS high-side drive integrated circuit or a step-up transformer. The existing technical scheme increases the complexity of the circuit design and improves the system design cost

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