Passive Ripple Mirror Circuit and Its Application in Pulse-Width Modulated DC-DC Converters

In this paper, a simple modular passive ripple mirror circuit (PRMC) is adopted for eliminating the inherent high frequency current ripple of pulse-width modulated (PWM) DC-DC converters. The PRMC doesn't require any additional active switches, driver circuits or any extra control; the cost can be saved easily. Only the reflected high frequency ripples are automatically induced and processed for proper cancellation with the original ripples. It turns out that not only the output power quality can be enhanced but also the inductance of the main power conversion circuit can be reduced greatly. In this paper, both the circuit structure and operation principle of the PRMC are described. Furthermore, the PRMC technique is then integrated into a family of PWM DC-DC converters, such as buck, boost, Cuk, Zeta, and SEPIC converters. Finally, as the demonstration, experimental results of the Cuk PWM converter integrated with PRMC are provided to verify the feasibility of the principle.