Single-stage isolation type LED driving power supply without electrolytic capacitor and control method thereof

Abstract

The invention relates to a single-stage isolation type LED driving power supply without an electrolytic capacitor and a control method thereof. The LED driving power supply comprises an AC input powersupply, a full-bridge rectification circuit, a flyback conversion circuit, an auxiliary circuit, an LED load and a control circuit, wherein the flyback conversion circuit works in a complete energy transfer mode and is used for realizing a power factor correction function and providing constant-current output for theLED load, the auxiliary circuit is composed of an auxiliary switch tube, a diodeand an energy storage capacitor and used for balancing the instantaneous power between input and output and absorbing voltage spikes generated by leakage inductance of a transformer, so low-frequencyripples of the LED load current are suppressed, and the leakage inductance energy of the transformer is effectively utilized. The LED driving power supply is advantaged in that a film capacitor can bedirectly utilized for replacing a high-capacity electrolytic capacitor, and the LED driving power supply has advantages of high efficiency, high power factor, long service life and the like.

Description

technical field [0001] The invention relates to a single-stage isolation type non-electrolytic capacitor LED drive power supply and a control method thereof. Background technique [0002] With its many advantages such as energy saving, environmental protection, high efficiency and long life, LED has become a new generation of green lighting source, and has been widely used in urban landscape lighting, emergency lighting, street lighting, home lighting and other fields. The driving power is the core component of LED lighting, so the development of high-performance, long-life LED driving power is the key to ensuring the luminous quality and overall performance of LED lighting. [0003] In the case of AC power supply, in order to meet the harmonic requirements of IEC61000-3-2, LED drive power must be corrected for power factor. When the power factor is 1, the input current and the input voltage are sine waves of the same frequency and phase, and its input power presents a puls...

AI Technical Summary

Problems solved by technology

When the power factor is 1, the input current and the input voltage are sine waves of the same frequency and phase, and its input power presents a pulsating form of twice the power frequency, while the output power of the LED is a constant power, so there is an instantaneous The imbalance between input power and constant output power leads to large low-frequency ripples in the output current. Usually, it is necessary to use a large-capacity electrolytic capacitor as an energy storage capacitor to balance, and the life of an electrolytic capacitor is usually only about 10,000 hours. The service life of LED light-emitting diodes is much lower than 100,000 hours, and the service life of electrolytic capacitors is greatly affected by the ambient temperature. Every time the temperature rises by 10 degrees, its service life will be reduced by about half. Therefore, the use of electrolytic capacitors limits LED lighting. The overall life of the product restricts the development of high-performance LED drive power

On the other hand, the volume of the electrolytic capacitor is relatively large, which also leads to an increase in the volume of the LED drive power supply, without utilizing miniaturization and improving power density.

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