Flicker-Free DC-DC LED Driver with Magnetic Integration and Multi-Mode Dimming Capabilities

Regulations on artificial lighting are becoming increasingly stringent. In the case of Light-Emitting Diode (LED) technology, one critical aspect is the current ripple through the lamp, as LEDs are highly sensitive to it. This work presents an LED driver specifically designed to eliminate current ripple across the lamp. To accomplish this, the LED load is repositioned in series with the input inductor, departing from the conventional SEPIC topology, thus obtaining a new topology. Achieving zero ripple in this inductor requires magnetic integration into a single core, which enables the ripple to be effectively steered to the other inductor. However, if this integration is not properly implemented, it may result in a current ripple even higher than that of a non-integrated configuration. In practice, although absolute ripple elimination is extremely difficult to attain, ultralow levels can still be achieved. Additionally, the proposed driver supports multiple dimming techniques, including Constant Current Reduction (CCR), Pulse-Width Modulation (PWM), and hybrid methods. This work, therefore, introduces a zero-ripple lamp-current dc–dc LED driver, with a focus on the derivation of the topology, main waveforms, and study of magnetic integration based on the leakage parameter that can be defined as a fingerprint for any given core configuration.