Composite VDMOS device possessing temperature sampling and over-temperature protection function

Abstract

A composite VDMOS device possessing a temperature sampling and over-temperature protection function belongs to the power semiconductor device field. In the invention, a VDMOS device, a polysilicon thermal diode and an over-temperature protection circuit are integrated. Through using a negative temperature characteristic of forward voltage drop of the polysilicon thermal diode, the polysilicon thermal diode is made on an insulating layer of a VDMOS device surface so as to realize sampling of a VDMOS device operating temperature. Based on a temperature sampling signal of the polysilicon thermal diode, the over-temperature protection circuit carries out partial pressure to a gate input voltage Vin of the whole composite VDMOS device so as to obtain a gate control voltage VG of the VDMOS device. Therefore, the over-temperature protection can be performed to the VDMOS device, which is characterized by: when the operating temperature of the VDMOS device reaches TH, turning off the VDMOS device; when the internal temperature drops to TL after the VDMOS device is turned off, starting the VDMOS device, wherein temperature return difference can be represented as a following formula: Delta T=TH-TL. By using the composite VDMOS device of the invention, the accurate sampling and the over-temperature protection can be performed to the VDMOS device so that thermal failure of the device can be avoided and a service life of the device can be prolonged. A structure is simple and sampling accuracy is high. The device is compatible with a VDMOS device technology. The device is monolithic and has many other advantages.

Description

technical field [0001] The invention belongs to the technical field of power semiconductor devices and relates to the over-temperature protection technology of VDMOS devices. Background technique [0002] VDMOS (Vertical Double Diffused Metal Oxide Semiconductor Field Effect Transistor) device is one of the mainstream devices of power semiconductors, and has been widely used in various power systems. Compared with bipolar transistors, it has fast switching speed, low loss, high input impedance, low driving power, and good frequency characteristics. VDMOS devices will inevitably generate power loss during the working process, and most of these power losses will be converted into heat energy, causing the temperature rise of the device. Excessive temperature has a great impact on the working performance and reliability of the device, which will cause the degradation of the device performance, and even lead to the failure of the device in severe cases. Studies have shown that ...

AI Technical Summary

Problems solved by technology

Excessive temperature has a great impact on the working performance and reliability of the device, which will cause the degradation of the device performance, and even lead to the failure of the device in severe cases.

Images