Low frequency ripple suppression circuit and control method

Abstract

The invention discloses a low frequency ripple suppression circuit and a control method. The low frequency ripple suppression circuit comprises an energy buffer and ripple suppression unit and an AC-DC power factor correction type constant current source circuit, wherein the energy buffer and ripple suppression unit is connected in parallel to a constant current source output voltage Vled of the front stage AC-DC power factor correction type constant current source circuit; the AC-DC power factor correction constant current source circuit is used for realizing power factor correction while providing a constant current output for the load; the energy buffer and ripple suppression unit is used for realizing front stage output voltage Vled low ripple; when the output voltage Vled of the frontstage AC-DC power factor correction type constant current source circuit rises instantaneously, energy on a second capacitor is transferred onto a first capacitor to charge the first capacitor; and when the output voltage Vled of the front stage AC-DC power factor correction type constant current source circuit drops instantaneously, the energy on the first capacitor is transferred onto the second capacitor to discharge the first capacitor. Through adoption of the low frequency ripple suppression circuit, LED load ripple can be reduced while ensuring no energy loss and increasing the system efficiency.

Description

Technical field [0001] The invention belongs to the technical field of LED lighting, and relates to an LED constant current drive circuit, in particular to a low-frequency ripple suppression circuit; meanwhile, the invention also relates to a control method of a low-frequency ripple suppression circuit. Background technique [0002] With the rapid development of the lighting industry, LED lamps with extremely high luminous efficiency have fully begun to replace traditional tungsten lamps or energy-saving lamps. With the gradual improvement and improvement of standards and regulations in various countries in the LED lighting industry, the LED market has become more Power factor requirements are getting higher and higher. As the cost pressure gradually increases, single-stage active power factor correction (PFC) LED constant current drive (isolated and non-isolated) has become a mainstream solution to market demand. [0003] However, in the commonly used single-stage active power fa...

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Problems solved by technology

[0011] Generally, the efficiency of DCDC is about 90% in the industry, so this solution must lose about 10% of the efficiency while increasing the system cost and system complexity, which is not the most ideal choice

[0012] Based on the above, the circuit of Scheme 1 adopts linear drive mode. Although the structure is simple, the efficiency loss is the largest, and the heat dissipation pressure of the system is increased. % or more efficiency, but increases the cost and complexity of the circuit structure

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