Abstract: A LED power supply with bi-level dimming receives an input voltage to supply power to an LED lamp, and adjusts the brightness of the LED lamp according to whether an external detection switch is triggered to be turned on. The LED power supply includes a conversion circuit, a switch, and an oscillation circuit. The conversion circuit converts the input voltage into an output voltage, and provides the output voltage to supply power to the LED lamp so as to control the LED lamp to provide a first brightness. The oscillation circuit provides a dimming signal with a fixed frequency and a duty cycle to the switch when the external detection switch is turned on so as to turn on and turn off the switch. The switch correspondingly adjusts the output voltage according to the dimming signal to control the LED lamp to provide a second brightness.

Abstract: A LED power supply with bi-level dimming receives an input voltage to supply power to an LED lamp, and adjusts the brightness of the LED lamp according to whether an external detection switch is triggered to be turned on. The LED power supply includes a conversion circuit, a switch, and an oscillation circuit. The conversion circuit converts the input voltage into an output voltage, and provides the output voltage to supply power to the LED lamp so as to control the LED lamp to provide a first brightness. The oscillation circuit provides a dimming signal with a fixed frequency and a duty cycle to the switch when the external detection switch is turned on so as to turn on and turn off the switch. The switch correspondingly adjusts the output voltage according to the dimming signal to control the LED lamp to provide a second brightness.

Abstract: A bi-level dimming LED power supply equipment adjusts the brightness of a plurality of LED lights according to whether an external detection switch is triggered turned on. The LED power supply equipment includes a plurality of LED power supplies, and the LED power supplies respectively include an input end and an output end. The input end receives an input voltage, and the output end includes a bus positive end, a bus negative end and a dimming end. The dimming end is commonly coupled to a first end of the external detection switch, and one of the bus positive end or the bus negative end is commonly coupled to a second end of the external detection switch and one end of the LED lights, and the other one of the bus positive end or the bus negative end is respectively coupled to the other ends of the LED lights.

Abstract: A control method for an LLC resonant converter includes the following steps. Firstly, the LLC resonant converter is enabled. Then, the sonant converter is operated in a first modulation mode, so that the magnitude of the output voltage is greater than or equal to an intermediate voltage value. When the magnitude of the output current is greater than zero, a determining step is performed to determine whether the magnitude of the output voltage is greater than a reference voltage value. When the determining result is satisfied, the LLC resonant converter is operated in the first modulation mode. When the determining result is not satisfied, the LLC resonant converter is operated in a second modulation mode, so that the magnitude of the output voltage is lower than the intermediate voltage value.

Abstract: A control method for an LLC resonant converter includes the following steps. Firstly, the LLC resonant converter is enabled. Then, the sonant converter is operated in a first modulation mode, so that the magnitude of the output voltage is greater than or equal to an intermediate voltage value. When the magnitude of the output current is greater than zero, a determining step is performed to determine whether the magnitude of the output voltage is greater than a reference voltage value. When the determining result is satisfied, the LLC resonant converter is operated in the first modulation mode. When the determining result is not satisfied, the LLC resonant converter is operated in a second modulation mode, so that the magnitude of the output voltage is lower than the intermediate voltage value.

Abstract: An operating method for a light-emitting diode (LED) power supply includes the following operations: controlling an output voltage to be a first voltage by a control circuit; detecting a load current by a detection circuit; maintaining the output voltage as the first voltage by a constant voltage control circuit when the load current is greater than zero, changing the output voltage from the first voltage to a second voltage by the control circuit when the load current is equal to zero, and the second voltage being greater than the first voltage.

Abstract: An operating method for a light-emitting diode (LED) power supply includes the following operations: controlling an output voltage to be a first voltage by a control circuit; detecting a load current by a detection circuit; maintaining the output voltage as the first voltage by a constant voltage control circuit when the load current is greater than zero, changing the output voltage from the first voltage to a second voltage by the control circuit when the load current is equal to zero, and the second voltage being greater than the first voltage.

Abstract: An electrical ballast includes an inverter circuit and a detection circuit. The inverter circuit is configured to receive a dc voltage and provide an output voltage to a lighting module. The detection circuit is electrically coupled to the inverter circuit and a voltage source, and configured to detect an ac voltage signal in the inverter circuit, and pull down the voltage source from a supply level to an under voltage locking level to shut down the inverter circuit on the condition that the ac voltage signal is greater than a threshold value, and restart the inverter circuit after a delay period.

Abstract: An electronic ballast system for signage light includes a first lamp string, a second lamp string, a first inverter and a second inverter. The first lamp string includes at least one first lamp tube. The second lamp string is connected with the first lamp string in series, and includes at least one second lamp tube. The first inverter is connected with the first lamp string for driving illumination of the first lamp string. The second inverter is connected with the second lamp string for driving illumination of the second lamp string. A frequency difference between a frequency of the first inverter and a frequency of the second inverter is in a range between 500 Hz and 5 kHz.

Abstract: A dimmable instant-start ballast for a plurality of LED lamps and/or a plurality of fluorescent lamps is provided, which includes an isolated dimming interface, a duty control device, a dimming switch, and an inverter circuit. The isolated dimming interface receives a dimming signal to generate a dimming voltage. The duty control device generates an operation signal according to the dimming voltage. The dimming switch periodically couples a first node to a ground according to the operation signal. The inverter circuit receives a rectified voltage and is coupled to the first node. When the first node is coupled to the ground terminal, the inverter circuit provides a lamp current for the LED lamps and/or the fluorescent lamps.

Abstract: A dimmable instant-start ballast for a plurality of LED lamps and/or a plurality of fluorescent lamps is provided, which includes an isolated dimming interface, a duty control device, a dimming switch, and an inverter circuit. The isolated dimming interface receives a dimming signal to generate a dimming voltage. The duty control device generates an operation signal according to the dimming voltage. The dimming switch periodically couples a first node to a ground according to the operation signal. The inverter circuit receives a rectified voltage and is coupled to the first node. When the first node is coupled to the ground terminal, the inverter circuit provides a lamp current for the LED lamps and/or the fluorescent lamps.

Abstract: A driving device provides output power to an illumination device including a plurality of filaments is provided. A first converting module converts input power into direct current (DC) power. The first converting module includes a pair of first input terminals receiving the input power and a pair of first output terminals coupled to a first node and a second node and outputting the DC power. A first capacitor is coupled between the first node and a third node. A second capacitor is coupled between the second and third nodes. The first clamping module is connected to a first specific capacitor in parallel. The first specific capacitor is the first capacitor or the second capacitor. A second converting module converts the DC power to generate the output power.

Abstract: A multi-output electronic ballast is disclosed. The multi-output electronic ballast is used to drive a plurality of lamp assemblies and includes an AC/DC converter, a first inverter, a second inverter, an auxiliary voltage generator, and a control circuit. The AC/DC converter converts an AC input voltage to a high DC voltage. The first inverter converts the high DC input voltage to a first AC voltage selectively. The second inverter converts the high DC voltage to a second AC voltage. The auxiliary voltage generator generates an auxiliary voltage. The control circuit receives the auxiliary voltage generating circuit and outputs a control signal to the first inverter according to the switching operation of a first external switch. When the control signal is transmitted to the first inverter, the first inverter comes into operation and converts the high DC voltage to the first AC voltage.

Abstract: A driving device provides output power to an illumination device including a plurality of filaments is provided. A first converting module converts input power into direct current (DC) power. The first converting module includes a pair of first input terminals receiving the input power and a pair of first output terminals coupled to a first node and a second node and outputting the DC power. A first capacitor is coupled between the first node and a third node. A second capacitor is coupled between the second and third nodes. The first clamping module is connected to a first specific capacitor in parallel. The first specific capacitor is the first capacitor or the second capacitor. A second converting module converts the DC power to generate the output power.

Abstract: A fluorescent electronic ballast including: a rectifier circuit, for receiving an AC power supply and converting the AC power supply into a DC power supply; an inverter circuit, coupled to a fluorescent driver circuit, for converting the DC power supply into a high-frequency AC power supply for driving a fluorescent; and a detection protection circuit, coupled to the rectifier circuit and the inverter circuit, for detecting the DC power supply provided by the rectifier circuit, and cutting off the electric connection between a control chip of the inverter circuit and all of power supply when the voltage of the direct current power supply is lower than a predetermined value, wherein the power supply at least includes the direct current power supply provided by the rectifier circuit.

Abstract: A fluorescent electronic ballast including: a rectifier circuit, for receiving an AC power supply and converting the AC power supply into a DC power supply; an inverter circuit, coupled to a fluorescent driver circuit, for converting the DC power supply into a high-frequency AC power supply for driving a fluorescent; and a detection protection circuit, coupled to the rectifier circuit and the inverter circuit, for detecting the DC power supply provided by the rectifier circuit, and cutting off the electric connection between a control chip of the inverter circuit and all of power supply when the voltage of the direct current power supply is lower than a predetermined value, wherein the power supply at least includes the direct current power supply provided by the rectifier circuit.

Abstract: A current-preheat electronic ballast includes an AC-to-DC converter, a controlling unit, an auxiliary voltage generator, and an inverter. The inverter is connected with the DC bus for converting a high DC voltage into an AC output voltage and generating a resonant current and a lamp filament current to a lamp group. The inverter includes a resonant circuit and a resonant capacitor adjusting circuit. The resonant circuit provides electric energy required to preheat the lamp group. The resonant capacitor adjusting circuit judges whether the inverter is enabled according to the detecting element. After the inverter has been enabled for a delayed time, two high-voltage switching terminals of the resonant capacitor adjusting circuit are correspondingly conducted or shut off, so that an equivalent resonant capacitance value of the resonant circuit is changed and a voltage drop across two ends of a lamp filament of the lamp group is changed.

Abstract: A current-preheat electronic ballast includes an AC-to-DC converter, a controlling unit, an auxiliary voltage generator, and an inverter. The inverter is connected with the DC bus for converting a high DC voltage into an AC output voltage and generating a resonant current and a lamp filament current to a lamp group. The inverter includes a resonant circuit and a resonant capacitor adjusting circuit. The resonant circuit provides electric energy required to preheat the lamp group. The resonant capacitor adjusting circuit judges whether the inverter is enabled according to the detecting element. After the inverter has been enabled for a delayed time, two high-voltage switching terminals of the resonant capacitor adjusting circuit are correspondingly conducted or shut off, so that an equivalent resonant capacitance value of the resonant circuit is changed and a voltage drop across two ends of a lamp filament of the lamp group is changed.

Abstract: The configurations of an end of lamp life protection circuit for a ballast and a method thereof are provided in the present invention. The proposed circuit includes a voltage-dividing circuit receiving an input voltage and outputting a first and a second divided voltages and a switch apparatus raising the first divided voltage when the second divided voltage is less than a first pre-determined threshold value and turning off the ballast when the first divided voltage is higher than a second pre-determined threshold value.

Abstract: A multi-output electronic ballast is disclosed. The multi-output electronic ballast is used to drive a plurality of lamp assemblies and includes an AC/DC converter, a first inverter, a second inverter, an auxiliary voltage generator, and a control circuit. The AC/DC converter converts an AC input voltage to a high DC voltage. The first inverter converts the high DC input voltage to a first AC voltage selectively. The second inverter converts the high DC voltage to a second AC voltage. The auxiliary voltage generator generates an auxiliary voltage. The control circuit receives the auxiliary voltage generating circuit and outputs a control signal to the first inverter according to the switching operation of a first external switch. When the control signal is transmitted to the first inverter, the first inverter comes into operation and converts the high DC voltage to the first AC voltage.