Efficiency regulation for led illumination

A light emitting diode (LED) driver that generates an LED current to drive an LED according to a dimming control, comprises:

• a clock generator, the clock generator generates an AC drive voltage;
• a current regulation module coupled to receive a dimming control, the current regulation module generates a current control and a mode control;
• a switching regulator coupled to the clock generator and the current regulation module, the switching regulator modulates the AC drive voltage in a brightness mode selected from a plurality of brightness modes according to the mode control;
• a rectifier and filter coupled to the switching regulator, the rectifier and filter rectifies and filters the modulated AC drive voltage to generate a drive voltage to drive the LED, the drive voltage being associated with the LED current that is a substantially direct current according to the current control;
• and
• wherein a first mode within the plurality of brightness modes results in the LED driver alternating between the active and inactive durations, such that the LED driver maintains a preferred driver efficiency during the active duration and is disabled from generating the LED current during the inactive duration.

A method of generating a load current to drive a load in a driver, comprising the steps of:

• (1) receiving a DC supply voltage and a dimming control;
• (2) generating a current control according to the dimming control;
• (3) generating and modulating an AC drive signal according to a plurality of brightness modes;
• (4) rectifying and filtering the modulated AC drive voltage to generate the load current to drive the load, the load current being controlled to a substantially direct current according to the current control during an active duration and an inactive duration;
• and
• wherein a first mode within the plurality of current control modes results in alternating active and inactive durations, such that the driver maintains a preferred driver efficiency during the active duration, and an output capacitor provides a supplemental current as the load current during the inactive duration.