Patent ID: 7688600

Claim:
A multi-resonance converter, for converting a first DC voltage into a second DC voltage, the convertor comprising: a half-bridge including two semiconductor switches and having an output formed by a connection point of the two semiconductor switches; a resonance capacitor; a transformer having a primary winding and a secondary winding, the output of the half-bridge connected to the primary winding through the resonance capacitor; two rectifier elements; an output inductor, the secondary winding connected to the output inductor through the two rectifier elements; an output capacitor connected to the two rectifier elements through the output inductor; and a controller configured to be supplied with a voltage across the output capacitor and a reference voltage, the controller further configured to control switching of the semiconductor switches alternately so that one of the semiconductor switches is respectively turned on at a predetermined time after the other semiconductor switch is turned off, and characterized in that in a lower range of power drawn from the converter, a mark-space ratio of the converter is controlled for selected respectively constant frequencies, the periods for the selected frequencies given by T 1 p =(n+½)*T 0 , where n is an integer depending on the drawn power and T 0 is the period of the oscillation, the frequency of which is dictated by the resonance capacitor and the series circuit of a stray inductance and a main inductance of the transformer.