In an embodiment, a phase circuit includes: a bidirectional output stage configured to be coupled between a first battery and a second battery; a memory configured to store a number of active phases, and an identifier; and a synchronization circuit configured to receive a first clock signal and determine a start time of a switching cycle of the bidirectional output stage based on the number of active phases, the identifier, and the first clock signal, where the phase circuit is configured to control the timing of the switching of the bidirectional output stage based on the start time.