Patent ID: 7583066

Claim:
A DC/DC up-down converter, comprising: a DC voltage source configured to provide an input voltage; first and second outputs configured to output first and second output voltages, respectively; a main switch coupled to the DC voltage source; an inductance having a first terminal, coupled to the main switch, and a second terminal, the inductance being configured to provide a coil current; a first output switch coupled in series with the first output and configured to control a direction of the coil current into the first output or into the second output; a free-wheeling switch coupled to the DC voltage source and configured to provide current flow in the inductance if the main switch is switched off and a controller configured to control the main, free-wheeling, and first output switches such that: the first output voltage is lower than the input voltage; the second output voltage is higher than the input voltage; the controller controls the first output switch such that, during one switching cycle, the coil current flows from the second terminal of the inductance into both outputs; and the controller controls the main switch in a transient state of the up-down converter, so that an average voltage on the first terminal of the inductance is equal to a voltage on the second terminal of the inductance.