Switching power converter controller for digital control of constant-power mode

A switching power converter, comprising:

• a transformer having a primary winding and a secondary winding, wherein the secondary winding is coupled to an output node for an output voltage;
• a power switch in series with the primary winding;
• a controller configured to control a cycling of the power switch so that an output current of the switching power converter equals a constant current during a constant-current mode;
• transition from the constant-current mode to a constant-power mode in response to the output voltage being greater than a maximum voltage of the constant-current mode;
• control the cycling of the power switch to regulate the output voltage to equal a first constant voltage while an output current of the switching power converter is within a first current range, wherein the first constant voltage is greater than the maximum voltage by a discrete voltage step, and
• calculate a first constant-power reference current by a division of a constant power of the constant-power mode by the first constant voltage, wherein the first current range includes the first constant-power reference current.

A switching power converter, comprising:

• a transformer having a primary winding and a secondary winding, wherein the secondary winding is coupled to an output node for an output voltage;
• a power switch in series with the primary winding;
• a controller configured to control a cycling of the power switch to regulate the output voltage to equal a maximum voltage during a constant-voltage mode, wherein the controller is further configured to:
• transition from the constant-voltage mode to a constant-power mode in response to an output current of the switching power converter being greater than a maximum current of the constant-voltage mode;
• control the cycling of the power switch to regulate the output current of the switching power converter to equal a first constant current while the output voltage of the switching power converter is within a first voltage range, wherein the first constant current is greater than the maximum current by a discrete current step, and
• calculate a first constant-power reference voltage by a division of a constant power of the constant-power mode by the first constant current, wherein the first voltage range includes the first constant-power reference voltage.

A switching power converter, comprising:

• a transformer having a primary winding and a secondary winding, wherein the secondary winding is coupled to an output node for an output voltage;
• a power switch in series with the primary winding;
• and
• a controller configured to:
• control a cycling of the power switch to regulate an output current of the switching power converter to equal a maximum constant current during a constant-current mode;
• transition from the constant-current mode to a constant-power mode in response to the output voltage being greater than a maximum voltage of the constant-current mode;
• control the cycling of the power switch to regulate the output current to equal a first constant current while the output voltage of the switching power converter is within a first voltage range, wherein the first constant current is less than the maximum constant current by a discrete current step, and
• calculate a first constant-power reference voltage by a division of a constant power of the constant-power mode by the first constant current, wherein the first voltage range includes the first constant-power reference voltage.