Single-stage AC-DC multi-output electrolytic-capacitor-free high-power LED driving power source

Abstract

The invention relates to a single-stage AC-DC multi-output electrolytic-capacitor-free high-power LED driving power source and a control method. The LED driving power source comprises an input filtercircuit, a bridgeless Boost PFC circuit, a half-bridge LLC resonant circuit and an LED load. The bridgeless Boost PFC circuit and the half-bridge LLC resonant circuit are integrated into a single-stage structure by sharing two switching tubes. A multi-series isolation transformer LLC converter drives the LED load. An LED driving circuit uses a common control strategy with a PFM and PWM variable duty cycle technology. In this control strategy, a power factor is increased, a DC bus voltage is lowered, output voltage ripple is reduced, and the required capacitance of the circuit is e reduced so that a ceramic capacitor with a long service life replaces an electrolytic capacitor to extend the service life of the driving power source. The circuit and the control strategy of the present invention have high efficiency, a high power factor, less components, low cost, low DC bus voltage, and no electrolytic capacitor.

Description

technical field [0001] The invention relates to a power conversion circuit, in particular to a single-stage AC-DC multi-output high-power LED drive circuit without electrolytic capacitors. Background technique [0002] The traditional high-power multi-output LED lighting drive circuit consists of a three-stage structure: the first stage is a power factor correction circuit unit, the sinusoidal alternating current is connected to the PFC circuit through the rectification bridge, and the PFC circuit provides a sinusoidal input current. The second stage is a DC-DC conversion unit, which provides a constant DC voltage for the subsequent circuit to drive the LED module. The third stage is the current balance unit, which realizes the uniform brightness of multiple LED strings by adjusting the current of each string of LED loads. The traditional three-level LED lighting drive circuit has problems such as complex structure, large number of components, low overall efficiency and ele...

AI Technical Summary

Problems solved by technology

[0003] The present invention aims at the problem of improving efficiency and removing electrolytic capacitors of LED drive power supply, and proposes a single-stage AC-DC multi-output high-power LED drive circuit without electrolytic capacitors, which has high efficiency, high power factor, small number of components, and low cost , low DC bus voltage, no electrolytic capacitors, etc.

Images