Abstract: A control circuit for a switch unit of a clocked power supply receives an auxiliary signal from a resonant transformer driven by the switch unit and detects reference crossing moments when the auxiliary signal crosses a reference value. A driver is controllable to switch the switch unit, and a synchronization circuit synchronizes a turn-on of the switch unit within a predetermined time interval around a zero crossing of a voltage present across the switch unit, or of a current flowing through the switch unit. The synchronization circuit receives information about the reference crossing moments and provides a turn-on signal to the driver with a fixed phase delay at the reference crossing moments, so as to define turn-on moments at which the driver is to turn on the switch unit.

Abstract: The invention involves a control circuit for a switch unit of a clocked power supply circuit, the switch unit being designed to effect input-side excitation of a resonant transformer arrangement, and comprises an input for receiving an auxiliary signal from the resonant transformer arrangement. The invention also includes a resonance converter that enables independent control of frequency and turn-on moments, or duty cycle, and thus enables a particularly efficient operation of the resonance converter, and a particularly precise regulation.

Abstract: A control circuit for a switch unit of a clocked power supply circuit, the switch unit being designed to effect input-side excitation of a resonant transformer arrangement, comprises an input for receiving an auxiliary signal from the resonant transformer arrangement. The auxiliary signal exhibits an essentially fixed phase relation to a load alternating current flowing through a resonant circuit of the transformer arrangement. The control circuit further comprises a phase detector designed to detect reference crossing moments when the auxiliary signal crosses a predefined reference value, a driver controllable to switch the switch unit, and a synchronization means designed to synchronize a turn-on of the switch unit by the driver with regard to a phase position with the auxiliary signal so as to achieve a turn-on of the switch unit within a predetermined time interval around a zero crossing of a voltage present across the switch unit, or of a current flowing through the switch unit.

Abstract: A control circuit for a switch unit of a clocked power supply circuit, the switch unit being designed to effect input-side excitation of a resonant transformer arrangement, comprises an input for receiving an auxiliary signal from the resonant transformer arrangement. The auxiliary signal exhibits an essentially fixed phase relation to a load alternating current flowing through a resonant circuit of the transformer arrangement. The control circuit further comprises a phase detector designed to detect reference crossing moments when the auxiliary signal crosses a predefined reference value, a driver controllable to switch the switch unit, and a synchronizer designed to synchronize a turn-on of the switch unit by the driver with regard to a phase position with the auxiliary signal so as to achieve a turn-on of the switch unit within a predetermined time interval around a zero crossing of a voltage present across the switch unit, or of a current flowing through the switch unit.