Abstract: A method of operating a switching power converter having at least one power switch controlled by a drive signal having a switching frequency is disclosed. The method includes monitoring an output power of the switching power converter, determining whether the output power has decreased below a threshold level and, in response to the output power decreasing below the threshold level, changing the switching frequency of the drive signal from a first switching frequency to a second switching frequency when an operating condition of the switching power converter is satisfied. Also disclosed are controllers and switching power converters (including PFC converters).

Abstract: A method of operating a switching power converter having at least one power switch controlled by a drive signal having a switching frequency is disclosed. The method includes monitoring an output power of the switching power converter, determining whether the output power has decreased below a threshold level and, in response to the output power decreasing below the threshold level, changing the switching frequency of the drive signal from a first switching frequency to a second switching frequency when an operating condition of the switching power converter is satisfied. Also disclosed are controllers and switching power converters (including PFC converters).

Abstract: A multiphase DC to DC converter includes an input, an output, at least first and second converters, an inductor, an output capacitor, and a drive circuit. The drive circuit is configured for switching the first and second converters with a predetermined phase shift therebetween. The output capacitor is operatively coupled between the first and second converters and the output. The inductor can be placed either at the input side or the output side. When placed at the input side, the inductor is operatively coupled between an input capacitor and the first and second converters. When placed at the output side, the inductor is operatively coupled between the first and second converters and the output capacitor. The multiphase DC to DC converter is capable of achieving lossless switching transitions and negligible ripple current in the output capacitor.

Abstract: A multiphase DC to DC converter includes an input, an output, at least first and second converters, an inductor, an output capacitor, and a drive circuit. The drive circuit is configured for switching the first and second converters with a predetermined phase shift therebetween. The output capacitor is operatively coupled between the first and second converters and the output. The inductor can be placed either at the input side or the output side. When placed at the input side, the inductor is operatively coupled between an input capacitor and the first and second converters. When placed at the output side, the inductor is operatively coupled between the first and second converters and the output capacitor. The multiphase DC to DC converter is capable of achieving lossless switching transitions and negligible ripple current in the output capacitor.

Abstract: A circuit for reducing the internal power losses of a soft switching full bridge converter at light loads and enables very high frequency operation without using a cold plate approach. In a preferred embodiment, the circuit includes a resonant inductor and blocking inductor on the primary side of the converter arranged so as to provide the reduced losses for zero voltage switching bridge converter. The circuit provides the above benefits even for converters having a power transformer with very low leakage inductance. The circuit is not dependent on the presence of a high leakage inductance for the power transformer. The circuit can be used in soft switched half bridge or full bridge converters. The inventive circuit can also be used in a hard switching full bridge or half bridge converter for achieving zero voltage switching at reduced cost with reduced losses at light load, if the operating duty cycle of the converter is set near fifty percent.

Abstract: A soft switched zero voltage transition full bridge converter for reducing power loss at very light loads for zero voltage switching (ZVS) converters operating at high frequency. The converter has four switches in two switching legs each of two switches connected in series between two input voltage terminals, junction points of the legs being coupled to a primary winding of a transformer, a secondary winding from which an output voltage of the converter is derived by rectifying and filtering. A pair of capacitive voltage dividers are connected between the input terminals, each formed by two small capacitors each having a parallel-connected diode. The output voltage is regulated by phase shift control of the switches. The capacitors are selected small enough for storing only enough energy to enable ZVS in conjunction with two resonant inductors. The converter enables reduced component size of the inductors and energy storage capacitors.