An Efficient Selective Harmonic Based Full Bridge DC-DC Converter for LED Lighting Applications

A novel power control is presented in full bridge converter to drive Light Emitting Diodes (LEDs). LEDs are current driven devices which require small voltage for current regulation. In this configuration, LED lamp is supplied by two voltage sources connected in series. One of the voltage source supplies directly to main portion of lamp power and other one delivers a small power through full bridge for regulation. This driver utilizes fifth harmonic component in the bridge output voltage which leads to reduction in the size of reactive components. The switching devices are operated at fundamental component of frequency. Hence reduced switching loss in full bridge results in high efficiency. Further, pulse width modulation (PWM) dimming control is incorporated. The simulation results are provided to confirm its validity.