A capacitive impedance balanced multi-channel led drive circuit

Abstract

The present invention proposes a capacitive impedance balanced multi-channel LED drive circuit, including a DC input power supply, a half-bridge switch circuit, a resonant inductor, a resonant capacitor, a parallel inductor, a transformer, a variable capacitor circuit, a balanced capacitor module, an LED light string module, Feedback control module and constant frequency control module. The n LED light string loads in the LED light string module are respectively connected in series with the n balanced capacitors in the balanced capacitor module and then connected in parallel to the secondary side of the transformer. When it is turned off, the feedback control module samples the secondary output voltage of the transformer and the primary resonant current, and compares them with the required reference voltage to generate a signal for controlling the switching tube in the variable capacitance circuit. The invention fixes the switching frequency of the half bridge and controls the output by adjusting the equivalent resonant capacitance, so that the load impedance characteristic is not affected by the switching frequency, realizes automatic current sharing, and has the function of LED lamp string open circuit protection.

Description

technical field [0001] The invention relates to the field of a multi-channel LED driving power supply, in particular to a multi-channel LED driving circuit using capacitance impedance to balance current. Background technique [0002] LED has the advantages of high efficiency, long life and energy saving, and is widely used in various lighting fields. However, due to the characteristics of the LED itself and the packaging technology, the brightness that a single LED lamp bead can provide is limited to a certain extent, and it is necessary to increase the number of LED lamp beads to obtain the required brightness. [0003] Although series connection can ensure the same current flowing through each lamp bead, in high-power occasions, sometimes hundreds of watts or even more output is required, and the number of lamp beads is greatly increased, making it difficult to obtain a larger output voltage. Using multi-channel parallel connection can solve the problem of excessive drivi...

AI Technical Summary

Problems solved by technology

However, due to the characteristics of the LED itself and the packaging technology, the brightness that a single LED lamp bead can provide is limited to a certain extent, and it is necessary to increase the number of LED lamp beads to obtain the required brightness

[0003] Although series connection can ensure the same current flowing through each lamp bead, in high-power occasions, sometimes hundreds of watts or even more output is required, and the number of lamp beads is greatly increased, making it difficult to obtain a larger output voltage

The use of multi-channel parallel connection can solve the problem of excessive driving voltage and facilitate subsequent maintenance. However, in order to achieve consistent luminous intensity, the current difference between channels and the conversion efficiency of the system need to be focused.

Images