A usb leakage protection chip based on mems switch

Abstract

The invention relates to an MEMS switch based USB electric leakage protection chip. The basic structure of the USB electric leakage protection chip comprises a magnetic field generation unit, a magnetic filed detection unit, a driving unit and an MEMS switch unit; the USB electric leakage protection chip is characterized in that the magnetic field generation unit comprises a magnetic core and VBUS and GND lines which are wound around the magnetic core; the magnetic core adopts a ferrite material; the magnetic filed detection unit comprises a Hall element, a constant-current source, an amplification circuit and a comparison circuit; the Hall element is a magnetic-sensitive element and used for detecting the magnetic field; the driving unit is used for supplying a relatively high driving voltage required by the action of the MEMS switches; and the MEMS switches are arranged on the VBUS and GND lines of the USB interface separately. The chip can be applied to electric leakage protection for the charging process of the equipment which is charged through the USB interface; and when electric leakage occurs, the MEMS switch is automatically switched on to cut off the charging circuit.

Description

【Technical field】 [0001] The invention belongs to the technical field of electrical safety, and relates to a MEMS switch-based USB leakage protection chip and a preparation method thereof. 【Background technique】 [0002] In our life, we cannot do without all kinds of electrical equipment. Leakage of electrical equipment will damage the equipment if it is light, and cause fire and personal injury or death if it is serious. According to statistics, in recent years in my country's fire accidents, electrical failures have become an important cause of fires, accounting for 30% of the total number of fires each year. Electrical failures have become a key issue that cannot be ignored in fire protection work. At the same time, electric shock accidents may occur if people touch the electrical equipment that leaks electricity. According to GB / T13870.1-2008 (Effects of electric current on humans and domestic animals Part I: General part), the current of adult is about 10mA, and the c...

AI Technical Summary

Problems solved by technology

Its defect is that it can only be applied to the monitoring of AC leakage current and the protection of the AC system. At the same time, because it is installed on the power supply side of the grid, once leakage protection occurs, the leakage protector will cut off the entire line, and other users on the same line Electrical equipment not working due to power outage

In the equipment that is charged through the USB interface, the existing technology generally adds a current limiting module to the rectification device (charging head), and its defect is that the small leakage current cannot be cut off, and the circuit structure of the rectification device will become more complicated

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