Power converter and controller for a power converter and manners of operation thereof

A controller configured to control a power converter, the power converter having a transformer, a low side switch for drawing current from a supply voltage through a primary winding of the transformer and a high side switch for coupling the primary winding of the transformer to a snubber capacitor, wherein the controller is configured to generate drive signals that control the opening and closing of the low side switch once during each of a series of switching cycles to form a regulated output voltage, and wherein the controller is configured to selectively control the high side switch according to:

• a mode of operation in which the high side switch is closed and then opened once during each of the series of switching cycles;
• and a mode of operation in which the high side switch is closed and then opened two times during each of the series of switching cycles, wherein the controller is configured to monitor a first voltage generated at a node between the low side switch and the high side switch for determining time instants for closing and opening the high side switch.

A controller configured to control a power converter, the power converter having a transformer, a low side switch for drawing current from a supply voltage through a primary winding of the transformer and a high side switch for coupling the primary winding of the transformer to a snubber capacitor, wherein a first voltage is generated at a node between the low side switch and the high side switch, and wherein the controller is configured to generate a drive signal that controls the opening and closing of the low side switch to form a regulated output voltage, and wherein the controller is configured to selectively operate in a mode in which the high side switch is closed during each of a series of switching cycles based on a comparison of the supply voltage to the first voltage and in a mode in which the high side switch is held open during each of a series of switching cycles thereby a current through the high side switch is passively rectified by a body diode of the high side switch, and wherein the controller is configured to select between the modes of operation according to a level of the supply voltage or load power.

A controller configured to control a power converter, the power converter having a transformer, a low side switch for drawing current from a supply voltage through a primary winding of the transformer and a high side switch for coupling the primary winding of the transformer to a snubber capacitor, wherein a first voltage is generated at a node between the low side switch and the high side switch, and wherein the controller is configured to generate a drive signal that controls the opening and closing of the high side switch to form a regulated output voltage, wherein the controller is configured to selectively operate in a mode in which the high side switch is closed during each of a series of switching cycles based on a comparison of the supply voltage to the first voltage and in a mode in which the high side switch closed during each of a series of switching cycles in response to a pulse signal, and wherein the controller selects between the modes of operation according to a level of the supply voltage or load power.