Abstract: A control device for a transistor of a switching converter rectifier generates a control signal of the transistor and includes a circuit to measure the conduction time of the body diode of the transistor cycle by cycle. When the conduction time is greater than a first threshold, the off time instant of the transistor is delayed by a first quantity in the next cycles, until the conduction time is less than the first threshold and greater than a second threshold. When the conduction time is between the first and second thresholds, the off time instant is delayed by a fixed second quantity in the next cycles until the conduction time is lower than the second threshold, with the second quantity less than the first quantity. When the conduction time is lower than the second threshold, the off time instant is advanced by the second quantity in the next cycle.

Abstract: A control device for a transistor of a switching converter rectifier generates a control signal of the transistor and comprises a circuit to measure the conduction time of the body diode of the transistor cycle by cycle. When the conduction time is greater than a first threshold, the off time instant of the transistor is delayed by a first quantity in the next cycles, until the conduction time is less than the first threshold and greater than a second threshold. When the conduction time is between the first and second thresholds, the off time instant is delayed by a fixed second quantity in the next cycles until the conduction time is lower than the second threshold, with the second quantity less than the first quantity. When the conduction time is lower than the second threshold, the off time instant is advanced by the second quantity in the next cycle.

Abstract: A half bridge switching dc-dc converter an input dc voltage to an output dc voltage. The converter includes a switching circuit for receiving the input dc voltage and generating a periodic square wave voltage oscillating from a high value corresponding to the input dc voltage to a low value corresponding to a reference voltage. The periodic square wave voltage oscillates at a main frequency with a main duty cycle equal to about 50% when the converter operates in a steady state. The converter further includes a conversion circuit for providing the output dc voltage from the square wave voltage based on the main frequency and on the main duty cycle. The converter still further comprises a switching control circuit controlling the switching circuit for temporarily varying the main duty cycle during at least one period of the square wave after a power on of the converter.

Abstract: A half bridge switching dc-dc converter an input dc voltage to an output dc voltage. The converter includes a switching circuit for receiving the input dc voltage and generating a periodic square wave voltage oscillating from a high value corresponding to the input dc voltage to a low value corresponding to a reference voltage. The periodic square wave voltage oscillates at a main frequency with a main duty cycle equal to about 50% when the converter operates in a steady state. The converter further includes a conversion circuit for providing the output dc voltage from the square wave voltage based on the main frequency and on the main duty cycle. The converter still further comprises a switching control circuit controlling the switching circuit for temporarily varying the main duty cycle during at least one period of the square wave after a power on of the converter.

Abstract: A SEPIC type voltage converter (101) comprises a transformer (40) having a primary winding (41) and a storage capacitor (33) connected in series, and a controllable switch (51) coupled in parallel with said series combination. The transformer has a first secondary winding (421) and a first rectifying diode (431) connected in series, and a first capacitor (441) coupled in parallel with said series combination, one terminal of said first capacitor (441) being coupled to an output terminal (451). The voltage converter also comprises feedback means (50; 53, 52) coupled to said output terminal (451) and controlling said controllable switch (51). The transformer further has a second secondary winding (62) and a second rectifying diode (63) connected in series, wherein this series combination is also coupled to said output terminal (451) in order to limit the voltage across the storage capacitor.

Abstract: A SEPIC type voltage converter (101) comprises a transformer (40) having a primary winding (41) and a storage capacitor (33) connected in series, and a controllable switch (51) coupled in parallel with said series combination. The transformer has a first secondary winding (421) and a first rectifying diode (431) connected in series, and a first capacitor (441) coupled in parallel with said series combination, one terminal of said first capacitor (441) being coupled to an output terminal (451). The voltage converter also comprises feedback means (50; 53, 52) coupled to said output terminal (451) and controlling said controllable switch (51). The transformer further has a second secondary winding (62) and a second rectifying diode (63) connected in series, wherein this series combination is also coupled to said output terminal (451) in order to limit the voltage across the storage capacitor.