In this paper, an analyze and describe step by step process of designing, feedback control and MATLAB simulation of a voltage bucking-boosting converter by combining KY and Synchronous Buck converter for power battery applications. Unlike the traditional buck-boost converter [1, 2, 10, 11], this converter has only the positive output voltage, different from the negative output voltage of the traditional inverting buck-boost converter. This converter operates only in continuous conduction mode. The output current is the non-pulsating waveform thereby not only the current stress on the output capacitor is reduced but also reducing the output voltage ripples. By Combining the KY converter with the synchronous buck converter, a positive buck-boost converter is obtained and uses the same power switches with no right-half-plane zero. So that the circuit is made to be compact and the corresponding cost to below.