ANALYSIS AND DESIGN

Two types of a voltage-mode resonant Cuk converter with a coupled-inductor, which are halfwave and full-wave types, are analyzed by introducing the effects of parasitic inductances. The characteristics of the coupled-inductor used in these resonant converters are investigated in detail. As the result, it is found that the voltage waveforms of the coupled-inductor operating at high frequency differs from that of conventional PWM Cuk converter, and that it affects the input and output current-ripple characteristics. This is due to some parasitic inductances existing in the resonant circuit loop and the diode reverse recovery. A method is proposed to satisfy the coupling condition of the coupled-inductor by suppressing the above effects.