Abnormality detection device for power switch

Abstract

The invention discloses an abnormality detection device of a power switch, which is connected to a current path of a power switch, comprising: a voltage dividing circuit with a voltage dividing node; a differential pressure switch connected to the dividing point of the voltage dividing circuit Between the voltage node and the current path of the power switch; when the voltage on the current path is less than a first set value, the differential pressure switch is turned on, so that the voltage of the voltage dividing node is less than a second set value, when the current When the voltage on the path is greater than or equal to the first set value, the differential pressure switch is turned off, and when the voltage of the voltage dividing node is greater than or equal to the second set value, an abnormal alarm can be generated accordingly. The present invention mainly judges whether the temperature-related impedance on the current path is abnormal according to whether the voltage value on a current path is greater than or equal to a set value when a power switch is turned on, and then determines whether an abnormality occurs in the power switch. The basis for the alert.

Description

technical field [0001] The invention relates to an abnormality detection device of a power switch, in particular to a related technology for generating an abnormality alarm based on whether the temperature-related conduction resistance of the power switch is abnormal. Background technique [0002] A power switch refers to a transistor that can withstand a large current, a small leakage current, and has better saturation conduction and cut-off characteristics under certain conditions. One of the most commonly used power switches is a metal oxide semiconductor field effect transistor (MOSFET). ). Because the power switch has the above characteristics, it is often used in power supply equipment, such as switching power supply, please refer to Figure 7 , an existing switching power supply includes a rectifier circuit 81, a power factor correction circuit 82 and a DC-to-DC conversion circuit 83, etc.; wherein: the power factor correction circuit 82 includes an inductor L1 locate...

AI Technical Summary

Problems solved by technology

However, also in the power factor correction circuit 82 of the switching power supply, based on circuit characteristics, its PFC controller still adopts hard switching for the control of the power switch S1, and the power switch S1 frequently operates under hard switching, in addition to generating losses In addition, it may also fail due to abnormal temperature rise

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