Earth leakage protection circuit and method

Abstract

The present invention discloses an earth leakage protection circuit and method. The earth leakage protection circuit comprises: a current detection circuit configured to detect a current flowing through a first switch connected with a main loop to obtain current detection signals showing the current flowing through the first switch, wherein if the current detection signals are lower than a first threshold value, it is determined that an input end generates a leakage phenomenon; a control circuit configured to control on-off of the first switch, wherein when the first switch is transiently switched on, the current design circuit detects the current flowing through the first switch, if the current detection signals are lower than the first threshold value, the first switch is switched off, and if the current detection signals reach the first threshold value, the first switch is switched on after the action of a switch protection circuit; and the switch protection circuit, wherein if thecurrent detection signals reach the first threshold value, time delay is performed for a while or the voltage of the input end is detected, and when the voltage of the input end reaches an expected value or an expected range, the control circuit switches on the first switch. The earth leakage protection circuit and method allow a switch tube to be switched on when the voltage is low so as to protect the switch tube from being damaged.

Description

technical field [0001] The present invention relates to the technical field of power electronics, and more specifically, to a leakage protection circuit and method. Background technique [0002] During the load installation process, due to the possibility of partial connection during the installation process, if the human body accidentally touches it at this time, it is easy to get an electric shock and affect the safe operation. For example, in the field of lighting, since many lamp holders still retain the interface for double-terminal input, when replacing the original lamp tube, the lamp tube with double-terminal input is generally used. The double-terminal input refers to setting the connectors of the AC input terminal at both ends of the lamp tube respectively. In this case, the operator generally inserts one end into the lamp holder first, and then inserts the other end. The part needs to be grasped at the end of the lamp tube, and it may touch the conductive metal a...

AI Technical Summary

Problems solved by technology

[0004] In view of this, the present invention proposes a leakage protection circuit and method for protecting the switch tube at the start of the switch tube conduction stage, which is used to solve the problem in the prior art that the switch tube is damaged due to a large input terminal voltage during the switch tube conduction stage. technical problem

Images