Patent ID: 8193739

Claim:
An apparatus for lighting LEDs comprising: an LED group load having the LEDs; a converter configured to generate a voltage applied to the LED group load; a current controller configured to control a current passing through the LED group load, wherein the current controller generates a current feedback signal according to a current passing through the LED group load; a voltage controller configured to control an output voltage provided by the converter wherein the voltage controller generates a voltage feedback signal according to an output voltage from the converter; a time division circuit configured to intermittently provide a current to the LED group load; and a selector configured to: during a period in which the time division circuit passes a current through the LED group load, select the current controller to control a current passing through the LED group load and thereby control an output voltage provided by the converter, and select the current feedback signal to PWM-control an output voltage provided by the converter; and during a period in which the time division circuit passes no current through the LED group load, select the voltage controller to control an output voltage provided by the converter, and select the voltage feedback signal to PWM-control an output voltage provided by the converter.