Multiphase parallel LED (Light-Emitting Diode) driving power supply and dimming method thereof

Abstract

The invention relates to a multiphase parallel LED (Light-Emitting Diode) driving power supply and a dimming method thereof. The driving power supply comprises an input rectifier, a PFC (Power Factor Correction) circuit, a switch parallel network, an LCL-T type resonant network, an output rectifier filter and the like. The switch parallel network consists of n parallel inversion modules; and when a high-power output is ensured, a current stress of a power device in each parallel module is reduced. Each parallel inversion module comprises two dimming modules with phase shifting and dimming functions; an output current of the driving power supply is changed by regulating a phase shifting angle of a half-bridge arm in each dimming module; and a dimming range is expanded and the whole-range dimming is implemented by phase shifting combination of two dimming modules of each parallel inversion module.

Description

technical field [0001] The invention relates to the technical field of LED driving power supply, in particular to a multi-phase parallel LED driving power supply and a dimming method. Background technique [0002] In recent years, the current situation of energy shortage has made people increasingly aware of the importance of energy conservation and emission reduction. As a new type of lighting source, LED has the advantages of long life, energy saving and environmental protection, and is widely used in high-power lighting occasions such as road lighting and tunnel lighting. LED dimming can save energy, adjust the visual effect of the space, and at the same time prolong the service life of LEDs and improve the reliability of LED lights. [0003] According to the volt-ampere characteristics of the LED, in order to ensure its reliable operation, the LED needs to be driven by a constant current. Most of the existing high-power LED drivers use LLC resonant converters to achieve...

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Problems solved by technology

[0003] According to the volt-ampere characteristics of the LED, in order to ensure its reliable operation, the LED needs to be driven by a constant current. Most of the existing high-power LED drivers use LLC resonant converters to achieve constant current output by changing the operating frequency. However, when the LED driver is required When adapting to different numbers of LEDs, the operating frequency of the resonant converter may need to be changed in a wide range, which requires high design requirements for EMI filters and magnetic components, and the circuit is easy to deviate from the resonance point, making the circuit unable to achieve constant current output; and as With the popularization and use of LEDs, the demand for LED dimming applications is becoming more and more extensive

Although the LLC resonant converter can realize the dimming of the LED by changing the working frequency, the equivalent resistance of the LED will change continuously during the dimming process, which will cause the voltage gain of the LLC to change continuously, making the circuit design More complicated and unable to achieve wide range dimming

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