Abstract: An illuminating device and a luminance switching device thereof for controlling luminance of light emitting states of LED light source are provided.

Abstract: An illuminating device and a luminance switching device thereof for controlling luminance of light emitting states of LED light source are provided.

Abstract: The present invention discloses an LED driving device with pulse width modulation (PWM) capable of preventing the LED display from flickering. The LED driving device primarily comprises a PWM unit for modulating the ON/OFF signal with a PWM cycle from one signal of higher resolution to two or more signals of lower resolution. The modulation is executed with the proviso that the duty cycle of the PWM cycle is almost or completely preserved. Accordingly, the LED will be lit more frequently and perform preset brightness with a higher refresh rate.

Abstract: This invention discloses a light-emitting semiconductor device with open-bypass function, which comprises two terminals providing a current, at least one LED unit and a bypass switch. Electrodes of the LED unit and the bypass switch are properly connected to the terminals, so that the bypass switch will provide an alternative path for current flowing through if the circuit of the LEDs unit between two terminals is open.