Precise current sharing control for multi‐channel LED driver based on switch‐controlled capacitor

Abstract

A switch-controlled capacitor (SCC)-based driver circuit is proposed for current sharing of multi-channel lightemitting diode (LED). The proposed circuit includes a transformer primary side and several secondary sides. Each secondary side as an independent unit includes an SCC module, a resonant inductor and an H-bridge to power twochannel LEDs. Two output channels within a capacitor unit achieve current sharing due to charging or discharging balance of SCC module. Since the current in each capacitor unit can be regulated independently, the proposed topology is accommodated with more units. The current sharing among different capacitor units can be realised by the adjustment of SCC module; therefore, the dimming also can be accomplished for multi-channel LEDs. The operating cycles of SCC module, the working mode and simplified equivalent circuit are analysed in detail. The relations of LED current versus the equivalent capacitance are examined. The performance is evaluated by four-channel prototype with input voltage of 48 V and rated power of 20 W. The output current is regulated from 180 to 350 mA per LED channel. The experimental results further prove that the proposed topology can effectively achieve current sharing of two LED channels, current sharing of four-channel LED and independent dimming.

A three‐leg resonant converter for two output LED lighting application with independent control

“…The advantages of LEDs which make them as a promising light source are high operating life, higher luminous efficiency, solid-state characteristic, eco friendliness, smooth dimming capability, low cost, and good color rendering property. [15][16][17][18][19][20][21][22] LED lighting applications need efficient light output, independent current regulation, and illumination control to reduce energy expenses. [4][5][6] The light output from LED is directly related to its forward current.…”

“…[1][2][3] At present, LEDs have entered in almost all lighting applications like signal lighting, street lighting, indoor lighting, transportation, liquid crystal display (LCD) backlighting, architectural lighting, and parking lighting. 18,21,[23][24][25][26] This paper proposes a driver circuit to drive two LED lamps of different power ratings using a three-leg resonant converter. For constant illumination, current needs to be regulated precisely.…”

A buck‐boost integrated high gain non‐isolated half‐bridge series resonant converter for solar PV/battery fed multiple load LED lighting applications

“…Independent control of these LED lamps and independent dimming are the essential features for these drivers. Many multiple load LED drivers are available in the literature . In Alonso et al, the number of transformers increases as the LED loads increase.…”

“…In Alonso et al, the number of transformers increases as the LED loads increase. In Liu et al, the number of secondary windings of transformer increases as the LED loads increase. Even though a single transformer is used in Luo et al, it needs a high‐frequency AC bus, along with more number of inductors and capacitors.…”

“…Even though a single transformer is used in Luo et al, it needs a high‐frequency AC bus, along with more number of inductors and capacitors. For such lighting applications, where isolation is not significant and essential, LED drivers presented in previous works may lead to increased cost. Several non‐isolated LED drivers for multiple loads are reported in previous studies .…”