Abstract:
A very large number of LED (Light Emitting Diode) driver circuits with optimal design and high efficiency are being proposed in the literature in the recent past. However, only a few such designs are commercially successful because of the complexity involved in the design of control c ircuit and also the cost of the driver circuit is a key factor. This paper presents the design and analysis of a buck converter with dual output having less number of switching devices, along with brightness control for LED lamps. Majority of LED drivers need a conversion stage in case of AC input and a transformer for isolation which increase the cost of LED lamps. The proposed circuit is based on coupled inductor which acts as the energy transfer element and also eliminates the need for a transformer, thus providing the required isolation between the power circuit and low voltage LED circuit. Soft switching technique such as ZVS (Zero Voltage Switching) is employed to avoid voltage spikes during turn-off due to the leakage inductance of inductors. The brightness of the LEDs is controlled and regulated using double PWM (Pulse Width Modulation) method. The converter thus has high overall efficiency and better regulation compared to other single stage LED driver circuits. The proposed converter is simulated in PSIM 9.0 platform.The effectiveness of the proposed converter is validated through experimental results.
