Improvement of Passive Current Balancing Control for Interleaved Synchronous DC-DC Converter

The Interleaved Synchronous Buck converter has the ability to achieve soft switching on all switches and the ability to passively balance current between phases if operated at an appropriate switching frequency. By using the proposed method of adjusting the switching frequency based on the average output current in [6] and [7], the current between phases can be balanced with just a single control loop. However, this method does not consider the decrease in the inductance of the buck inductor when the load current increases, leading to control deviation and unbalanced current between phases. This paper proposes an improved control method to reduce the impact of inductance decrease on the self-balancing capability of current between phases. Simulation results with a 380W two-phase interleaved synchronous buck converter are used to verify the correctness of proposed control method.