A novel inductor-coupled step-up-down converter

In this paper, a step-up-down converter with a positive output voltage is presented, which combines the KY converter and the traditional synchronously rectified (SR) buck converter. By doing so, the problem in voltage bucking of the KY converter can be solved, thereby increasing the application capability of the KY converter. Aside from this, such a converter possesses the non-pulsating output current, thus not only decreasing the current stress on the output capacitor but also reducing the output voltage ripple. Above all, the KY converter and the SR buck converter, combined into a step-up-down converter with no right-half plane zero, use the same power switches and have two inductors coupled together, thereby causing the circuit to be simplified and the cost to be down.