Abstract: A power converter comprises a series arrangement of a first main current path of a first controllable switch (M2) and a second main current path of a second controllable switch (M3). The series arrangement is arranged to receive a DC-input voltage (V1). A series arrangement of an inductance (L) and a capacitance (2) is arranged in parallel with the second main current path. An output node (NO) which is coupled to the inductance (L) supplies an output voltage (VO) of the power converter. The power converter further comprises a means (M1) for varying the capacitance (2). A controller (1) controls the first controllable switch (M2) and the second controllable switch (M3) with a variable repetition frequency (fr) to stabilize the output voltage (VO), and controls the means (M1) for varying to vary the capacitance (2) or the inductance (L) in dependence on an output power of the power converter.

Abstract: A power circuit comprises a power supply (1) operable in a burst mode having on and off alternating phases and a continuous mode, a switch (4), a phase detector (5) for detecting the burst mode phase of the power supply (1) and for generating a signal indicative of the phase of the power supply (1), and a switch disabler (6) dependent on the signal from the phase detector (5) for disabling the switch (4) depending on the phases of the burst mode.