Power Supply For Semiconductor Light Emitting Device And Illuminating Device

Abstract

The present invention provides a power supply for a semiconductor light emitting device capable of efficiently modulating and driving a current-driven semiconductor light emitting device. An LED 31, a switching element 32, which modulates and drives the LED 31, and an average current detector 12, which detects an average current flowing through the LED 31, are connected to a voltage source 11. When the LED 31 is modulated and driven by the switching element 32, blinking or light quantity of the LED is controlled, and the LED 31 then emits modulated light. The average current detector 12 detects an average light quantity emitted from the LED 31 and then controls the voltage source to output a voltage so that the average current flowing through the LED 31 can be almost constant. As a result, the average light quantity may be kept almost constant with or without modulation of the LED 31.

Dependencies are inferred from the claim text.