Abstract: A solid light source lighting device includes: a step-down chopper circuit including a switching element and outputting a DC power by turning on and off the switching element; a capacitor connected in parallel to a solid light source connected across output terminals of the step-down chopper circuit; and a control circuit determining a control value for a switching operation of the switching element based on a dimming signal for indicating a dimming ratio of the solid light source, and performing switching control of the switching element based on the control value. When performing switching control of the switching element so that the dimming ratio becomes high based on the dimming signal indicating a first dimming ratio, the control circuit performs the switching control of the switching element based on the control value that becomes a second dimming ratio higher than the first dimming ratio for a prescribed time period.

Abstract: A solid light source lighting device includes: a step-down chopper circuit including a switching element and outputting a DC power by turning on and off the switching element; a capacitor connected in parallel to a solid light source connected across output terminals of the step-down chopper circuit; and a control circuit determining a control value for a switching operation of the switching element based on a dimming signal for indicating a dimming ratio of the solid light source, and performing switching control of the switching element based on the control value. When performing switching control of the switching element so that the dimming ratio becomes high based on the dimming signal indicating a first dimming ratio, the control circuit performs the switching control of the switching element based on the control value that becomes a second dimming ratio higher than the first dimming ratio for a prescribed time period.

Abstract: An LED driver circuit prevents an increase in output voltage of a DC/DC converter in an open circuit condition associated with removal or failure of an LED lighting device. A DC power source provides a first DC voltage across positive and negative voltage rails. A DC/DC converter includes a switching element which when turned ON/OFF provides a second DC voltage across first and second ends of a capacitor which further define first and second LED lighting device connection terminals. A control circuit, upon receiving a drive power signal, turns ON/OFF the switching element to provide constant current control. A power supply circuit is coupled between the second LED lighting device connection terminal and the negative voltage rail and generates the drive power signal to the control circuit during a detected lighting condition. The power supply circuit further disables the drive power signal during a detected open circuit condition.

Abstract: An illumination device includes one or more LED's and a power supply configured to convert energy from a commercial AC power source and drive said LED's. The power supply includes a rectifier circuit, a phase detection circuit receiving an output voltage from the rectifier circuit and a switching element. A circuit includes the one or more LED's, an inductive element and a diode, and is coupled on a first end to the rectifier circuit and coupled on a second end to ground through the switching element. A current sensor is positioned to detect a current flowing to the light-emitting diode. A control circuit is coupled to receive the detected current and the detected phase of the rectified output voltage, and further coupled to the switching element and configured to generate a PWM signal for driving the switching element at a frequency higher than a commercial AC frequency.

Abstract: A lighting device reliably detects a status (i.e., existence or absence) of a load connection, and enables or disables power output based on the detected load connection status. The device includes a DC-DC converter having input and output terminals, and a DC current conducting element coupled across the output terminals. A load terminal is also coupled across the output terminals and configured to receive an LED unit. A load detection circuit coupled between an input terminal and the load terminal detects the connection status of an LED unit via a DC current passing through the load terminal, and controls a switching operation of the DC-DC converter based on the detected connection status. A diode coupled between the load terminal and the DC current conducting element blocks a DC current path from the input terminals to the load detection circuit through the DC current conducting element.

Abstract: An LED power-source circuit includes an input filter circuit including noise prevention capacitors and a line filter, a diode bridge connected to the input filter circuit, a smoothing capacitor connected to an output of the diode bridge and having a capacitance of 1 ?F or less, a DC-DC conversion circuit connected to the smoothing capacitor, and an LED assembly connected to an output of the DC-DC conversion circuit. Grounding capacitors are coupled to ground from an input power line between the line filter and the diode bridge. The total capacitance from the input power line to ground is set to be 1/200 or less of that of the smoothing capacitor.

Abstract: A system and method for powering a light-emitting element in an illumination device includes a DC power supply with the light-emitting element coupled across a positive output terminal and a negative output terminal of the DC power supply. A switching element is coupled between the light-emitting element and the negative output terminal. An average current value across the light-emitting element is measured each time the switching element is turned on. A control circuit generates a PWM signal having a pulse width determined based on the calculated average current value and a predetermined target value, and applies the PWM signal to drive the switching element on and off in accordance with the determined pulse width, and a current is generated across the light-emitting element.

Abstract: A lighting device reliably detects a status (i.e., existence or absence) of a load connection, and enables or disables power output based on the detected load connection status. The device includes a DC-DC converter having input and output terminals, and a DC current conducting element coupled across the output terminals. A load terminal is also coupled across the output terminals and configured to receive an LED unit. A load detection circuit coupled between an input terminal and the load terminal detects the connection status of an LED unit via a DC current passing through the load terminal, and controls a switching operation of the DC-DC converter based on the detected connection status. A diode coupled between the load terminal and the DC current conducting element blocks a DC current path from the input terminals to the load detection circuit through the DC current conducting element.

Abstract: An LED driver circuit prevents an increase in output voltage of a DC/DC converter in an open circuit condition associated with removal or failure of an LED lighting device. A DC power source provides a first DC voltage across positive and negative voltage rails. A DC/DC converter includes a switching element which when turned ON/OFF provides a second DC voltage across first and second ends of a capacitor which further define first and second LED lighting device connection terminals. A control circuit, upon receiving a drive power signal, turns ON/OFF the switching element to provide constant current control. A power supply circuit is coupled between the second LED lighting device connection terminal and the negative voltage rail and generates the drive power signal to the control circuit during a detected lighting condition. The power supply circuit further disables the drive power signal during a detected open circuit condition.

Abstract: An LED power-source circuit includes an input filter circuit including noise prevention capacitors and a line filter, a diode bridge connected to the input filter circuit, a smoothing capacitor connected to an output of the diode bridge and having a capacitance of 1 ?F or less, a DC-DC conversion circuit connected to the smoothing capacitor, and an LED assembly connected to an output of the DC-DC conversion circuit. Grounding capacitors are coupled to ground from an input power line between the line filter and the diode bridge. The total capacitance from the input power line to ground is set to be 1/200 or less of that of the smoothing capacitor.

Abstract: An illumination device includes one or more LED's and a power supply configured to convert energy from a commercial AC power source and drive said LED's. The power supply includes a rectifier circuit, a phase detection circuit receiving an output voltage from the rectifier circuit and a switching element. A circuit includes the one or more LED's, an inductive element and a diode, and is coupled on a first end to the rectifier circuit and coupled on a second end to ground through the switching element. A current sensor is positioned to detect a current flowing to the light-emitting diode. A control circuit is coupled to receive the detected current and the detected phase of the rectified output voltage, and further coupled to the switching element and configured to generate a PWM signal for driving the switching element at a frequency higher than a commercial AC frequency.

Abstract: The ballast of the present invention includes a DC power supply, an inverter circuit, a load circuit, and an integrated control circuit. The integrated control circuit controls the switching elements of the DC power supply and the inverter circuit. The integrated control circuit includes a first control unit, a second control unit, and a driver circuit. The first control unit generates a first control signal for control of the switching element of the DC power supply. The second control unit generates a second control signal for control of the switching elements of the inverter circuit. The driver circuit provides drive signals for driving each one of the switching elements of said DC power supply and the inverter circuit in accordance with the first control signal and the second control signal.

Abstract: The ballast of the present invention includes a DC power supply, an inverter circuit, a load circuit, and an integrated control circuit. The integrated control circuit controls the switching elements of the DC power supply and the inverter circuit. The integrated control circuit includes a first control unit, a second control unit, and a driver circuit. The first control unit generates a first control signal for control of the switching element of the DC power supply. The second control unit generates a second control signal for control of the switching elements of the inverter circuit. The driver circuit provides drive signals for driving each one of the switching elements of said DC power supply and the inverter circuit in accordance with the first control signal and the second control signal.

Abstract: A discharge lamp lighting device has first switching means for converting AC power into DC power and second switching means for converting the DC power into a high frequency power, the first switching means being driven subsequently to a driving of the second switching means, and the device is arranged for intermittently applying a pulse voltage to a discharge lamp during its dimming lighting, whereby any secondary voltage can be effectively lowered and any flash apt to occur during the dimming lighting can be restrained.

Abstract: This invention relates to a method of sending and receiving signals when taking photographs with flash by exchanging information obtained on the camera side and the flash side and flash device for this method.Its aim is to take photographs with flash avoiding mutual interference between the camera signal and flash signal through control of the light emission on the flash side and by stopping the transmission of the flash signal to the camera side, while sending camera signal from the camera side to the flash side when sending flash signal generated on the flash side to the camera side.

Abstract: The aperture value in a camera having a flash unit is controlled by a frequency signal from the flash unit. The frequency of the signal is variable in accordance with the light emission characteristics of the flash unit.

Abstract: A camera flash photographing control device having a signal conversion element which generates step wave voltage for which a signal level is gradually varied as time passes, by the operation of a counter which receives a pulse signal. A signal conversion element is operated as an A-D converter in which digital signal output which corresponds to a required signal level is obtained by converting both analogue signals of luminance information of an object and iris information of a photographing lens into said required signal level at the time of light measurement before shutter release. A signal conversion element is operated as a digital-analogue converter in which analogue signal output which corresponds to a pulse signal is obtained by converting the digital signal input of film sensitivity information into a required pulse signal at the time of shutter control after shutter release.

Abstract: A camera flash device is provided for photography requiring the use of a flash by transmitting plural information from the flash side to the camera side.The flash device includes a plural flash signal generation circuit which generates flash signals from said flash side, as well as common terminal to which any two flash signals are sent from said plural flash signal generation circuit.A control circuit prevents sending one signal of said two signals, both signal pass common terminal, while the other is sent.

Abstract: An adaptor for a camera for operating multiple flash units with a single camera device in which all of the flash units simultaneously emit light. Output signals from each of the flash units indicating that the corresponding individual flash unit is ready to emit light are coupled to corresponding inputs of a logical product circuit such as an AND gate. The single output of the AND gate is coupled to a single corresponding input of the camera device. The X contact of the camera device is coupled in common to the actuation terminals of each of the flash units.