Abstract: A filter circuit comprises a resistor-capacitor (RC) circuit, a comparator circuit, and an output control circuit. The RC circuit is configured to generate a ripple voltage according to the PWM signal. The comparator circuit couples with the RC circuit, and is configured to compare the ripple voltage with a first reference voltage, and output a switch signal according to a comparison result. The output control circuit couples with the comparator circuit and the RC circuit, and is configured to generate an output signal according to the switch signal and the PWM signal. When a duty ratio of the PWM signal is larger than a predetermined threshold value, the output signal is corresponding to the PWM signal. When the duty ratio of the PWM signal is smaller than the predetermined threshold value, the output signal is not corresponding to the PWM signal.

Abstract: A filter circuit comprises a resistor-capacitor (RC) circuit, a comparator circuit, and an output control circuit. The RC circuit is configured to generate a ripple voltage according to the PWM signal. The comparator circuit couples with the RC circuit, and is configured to compare the ripple voltage with a first reference voltage, and output a switch signal according to a comparison result. The output control circuit couples with the comparator circuit and the RC circuit, and is configured to generate an output signal according to the switch signal and the PWM signal. When a duty ratio of the PWM signal is larger than a predetermined threshold value, the output signal is corresponding to the PWM signal. When the duty ratio of the PWM signal is smaller than the predetermined threshold value, the output signal is not corresponding to the PWM signal.

Abstract: A lighting system includes a lighting source module, which includes an alternating-current input terminal and a direct-current input terminal. When an alternating-current power source is supplied, the alternating-current power source drives the lighting source module through the alternating-current input terminal for generating light. When the alternating-current power source is not supplied, a direct-current power source drives the lighting source module through the direct-current input terminal for generating light.

Abstract: A light-emitting diode (LED) device including an LED module and a driver is provided. The LED module includes a voltage sensing module and an LED. The voltage sensing module generates a reference voltage. The driver includes a power converting module, a current processing module, a feedback module and a controller module. The power converting module converts an alternating current (AC) into a driving current for driving the LED to emit a light. The current processing module converts the driving current into a sensing voltage. The feedback module compares the sensing voltage with a reference voltage and outputs a level signal according to a magnitude relationship of the sensing voltage and the reference voltage. The controller module outputs a pulse width modulation (PWM) signal to the power converting module according to the level signal. The power converting module controls the magnitude of the driving current according to the PWM signal.

Abstract: A light-emitting diode (LED) device including an LED module and a driver is provided. The LED module includes a voltage sensing module and an LED. The voltage sensing module generates a reference voltage. The driver includes a power converting module, a current processing module, a feedback module and a controller module. The power converting module converts an alternating current (AC) into a driving current for driving the LED to emit a light. The current processing module converts the driving current into a sensing voltage. The feedback module compares the sensing voltage with a reference voltage and outputs a level signal according to a magnitude relationship of the sensing voltage and the reference voltage. The controller module outputs a pulse width modulation (PWM) signal to the power converting module according to the level signal. The power converting module controls the magnitude of the driving current according to the PWM signal.

Abstract: A backlight module includes a light guide plate, at least one first lighting element, and at least one second lighting element. The light guide plate has a first side surface and a second side surface opposite the first side surface. The first lighting element is disposed on the first side surface and has at least three light emitting diodes of different colors. The second lighting element is disposed on the second side surface and has at least three light emitting diodes of different colors. The arrangement of the light emitting diodes of the first lighting element is different from the arrangement of the light emitting diodes of the second lighting element.

Abstract: A backlight module includes a light guide plate, at least one first lighting element, and at least one second lighting element. The light guide plate has a first side surface and a second side surface opposite the first side surface. The first lighting element is disposed on the first side surface and has at least three light emitting diodes of different colors. The second lighting element is disposed on the second side surface and has at least three light emitting diodes of different colors. The arrangement of the light emitting diodes of the first lighting element is different from the arrangement of the light emitting diodes of the second lighting element.