High power LED drive circuit with emergency function

Abstract

The invention relates to a high power LED drive circuit with the emergency function, comprising a rectifying and filtering unit, a reverse excitation unit, a constant current driving unit and an emergency unit, wherein the rectifying and filtering unit is connected with the input end of the LED drive circuit and is used for rectifying and filtering the input alternating current signals; the reverse excitation unit is connected with the rectifying and filtering unit and is used for PWM wave modulation according to load change; the constant current driving unit is connected with the reverse excitation unit and is used for driving the LED to work at constant current; and the emergency unit is connected with the reverse excitation unit and provides power to the constant current driving unit when no alternating current input is detected by detecting the current of the reverse excitation unit. The LED drive circuit is simple and can automatically switch to the emergency power supply so as not to go out even though the mains supply has failure. The leakage current of the cells in the circuit is almost zero, thus ensuring the standby working time of the cells.

Description

technical field [0001] The present invention relates to an LED drive circuit, more specifically, to a high-power LED drive circuit with emergency function. Background technique [0002] For special lamps with batteries, it is necessary to design a circuit to switch between mains and batteries. The usual switching circuit is relatively complex in design. The invention patent with the application number of 200810061210.6 "A Circuit of LED Lighting Lamp and LED Light Using the Circuit" discloses a circuit of LED lighting emergency lights. The circuit starts the emergency circuit through the power failure identification circuit, and uses a single-pole switch as the switching circuit. The added circuit identification circuit of the circuit has complex design, reduces reliability and increases power consumption. Another example is the utility model patent "Emergency Power Supply for Cordless Telephones" whose application number is 94207217.0, which uses a relay to control the w...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a high-power LED drive circuit with an emergency function in view of the defect of the complex switching circuit between the commercial power and the storage battery in the prior art LED drive circuit

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