Control method of light emitting diode (LED) constant current power supply and LED constant current power supply circuit

Abstract

The invention relates to a control method of a light emitting diode (LED) constant current power supply and an LED constant current power supply circuit. In the invention, the control method of the LED constant current power supply is as follows: extracting an input voltage signal, an input current signal and a feedback voltage signal, then inputting the signals to a control circuit; converting the acquired signals into digital signals by the control circuit, adding a frequency jitter signal; carrying out logical operation to obtain a pulse signal for controlling a switch to work; and isolating the high-frequency alternative current by the high-frequency transformer so as to perform constant current driving on the LED. In the invention, the LED constant current power supply comprises a control circuit, a power supply unit, an input voltage detection unit, an output frequency jitter control unit, an output voltage detection unit, a primary current detection unit, a switch S1, a high frequency transformer and an output filter unit. The circuit of the invention can automatically adapt to the change of load LEDs and eliminate the impact of the circuit parameter change on working condition, thereby ensuring long-term stable work of the circuit.

Description

technical field [0001] The invention relates to a control method of an LED constant current power supply and an LED constant current power supply circuit. Background technique [0002] As LED lamps are more and more widely used in the lighting field, the requirement for a driving power supply that can meet the requirements of high performance and long life of LED lamps is becoming more and more urgent. According to the technical standards of LED lighting equipment, LED drive power must meet safety regulations and electromagnetic compatibility regulations. And it needs to be small in size and work continuously for a long time in a high temperature environment. The traditional design method of switching power supply is difficult to meet its requirements. Coupled with the special electrical properties of the LED itself, the consistency of the traditional power supply design method in mass production is more prominent. [0003] At present, a better driving solution is the LM3...

AI Technical Summary

Problems solved by technology

[0005] Its disadvantages are: 1. The power factor compensation circuit of external passive components in dotted line frame 1 can only reach a power factor of 0.75 in mass production; Consistency is adversely affected; 3. Using non-isolated methods will cost more when meeting security specifications

Its disadvantage is that the internal mode is fixed, and the adaptability to different practical applications is poor

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