Switching power converter with efficient switching control signal period generation

A method comprising:

• generating a switch control signal to control conductivity of a switch included in a switching power converter, wherein controlling conductivity of the switch causes an input current to the switching power converter to vary in approximate proportion to a time varying voltage source signal supplied to the switching power converter;
• determining a period of the switch control signal so that the period of the switch control signal varies in accordance with at least one of:
• (i) the period of the switch control signal trends inversely to estimated power delivered to a load coupled to the switching power converter;
• (ii) the period of the switch control signal trends inversely to instantaneous voltage levels of the voltage source signal;
• and
• (iii) the period of the switch control signal trends directly with a line voltage level of the time-varying voltage source signal;
• determining a pulse width of the switch control signal in response to at least one of:
• (i) the determined period of the switch control signal, (ii) the instantaneous voltage levels of the voltage source signal, and (iii) a voltage level of the output voltage signal of the switching power converter;
• and
• providing the switch control signal to the switching power converter.

An apparatus comprising:

• means for generating a switch control signal to control conductivity of a switch included in a switching power converter, wherein controlling conductivity of the switch causes an input current to the switching power converter to vary in approximate proportion to a time varying voltage source signal supplied to the switching power converter;
• means for determining a period of the switch control signal so that the period of the switch control signal varies in accordance with at least one of:
• (i) the period of the switch control signal trends inversely to instantaneous power transferred to the switching power converter;
• (ii) the period of the switch control signal trends inversely to voltage level changes of the voltage source signal;
• and
• (iii) the period of the switch control signal trends directly with a line voltage level of the time-varying voltage source signal;
• and
• means for determining a pulse width of the switch control signal in response to at least one of:
• (i) the determined period of the switch control signal, (ii) a voltage level of the voltage source signal, and (iii) a voltage level of the output voltage signal of the switching power converter.