Abstract: The present invention relates to a driver device for driving a load, in particular an LED unit having one or more LEDs, comprising input terminals for receiving an input voltage from an external power source for powering the load, and a connection unit for connecting the input terminals to each other and for providing a current path for a bleeding current, wherein the connection unit comprises a first current path for connecting the input terminals in a first current direction and a second current path for connecting the input terminals in a second current direction opposite to the first current direction, wherein the connection unit comprises a first current control unit for controlling the bleeding current in the connection unit, and wherein the first and the second current path each comprises a second current control unit for controlling the bleeding current in the respective current path.

Abstract: In at least one embodiment, the controller senses a leading edge, phase cut AC input voltage value to a switching power converter during a cycle of the AC input voltage. The controller senses the voltage value at a time prior to a zero crossing of the AC input voltage and utilizes the voltage value to determine the approximate zero crossing. In at least one embodiment, by determining an approximate zero crossing of the AC input voltage, the controller is unaffected by any disturbances of the dimmer that could otherwise make detecting the zero crossing problematic. In at least one embodiment, the controller approximates the AC input voltage using a function that estimates a waveform of the AC input voltage and determines the approximate zero crossing of the AC input voltage from the approximation of the AC input voltage.

Abstract: Discoloration and deformation of a resin case triggered by heat generation from a failed circuit component at the end of the life of an arc tube are prevented without increasing the cost and size. A lighting unit that lights a light source with an inverter while receiving electric power from an AC power supply, and that contains a lighting circuit that includes a plurality of circuit components inclusive of capacitors. Among the capacitors, all capacitors with an applied voltage of 50V or greater (C4, C5, C6, C7, C8, CD1 and CD2) are foil type film capacitors with exceptions of smoothing electrolytic capacitors (CD1 and CD2).

Abstract: Systems and methods are disclosed that facilitate sensing a pulse in a ballast circuit for a lamp when the lamp is in an end-of-life (EOL) stage or when the lamp is experiencing an arcing conduction condition, such as may occur when a contact between the lamp and its holder is compromised. Upon sensing the pulse, a microcontroller may distinguish between EOL and arcing conditions based on detected pulse width(s), and may initiate an appropriate response. For instance, if the pulse is due to an arcing event, the microcontroller may interrupt lamp operation for a brief period before restarting the lamp to mitigate the arcing condition. If the pulse is caused by an EOL condition, the microcontroller may place the lamp in a preheat or restarting mode to hasten lamp failure. In either case, responses to the sensed pulse mitigate the occurrence of dangerously high lamp temperatures that may damage lamp sockets.

Abstract: A cold cathode fluorescent lamp drive apparatus for lighting a cold cathode fluorescent lamp is disclosed. The cold cathode fluorescent lamp drive apparatus includes an abnormal current holding unit that is configured to hold an abnormal current that flows in the cold cathode fluorescent lamp, and a control unit that is configured to stop an operation of supplying a voltage to the fluorescent lamp according to the abnormal current held by the abnormal current holding unit.

Abstract: A vehicular lamp used in a vehicle, includes: a light source for emitting light in accordance with a voltage given thereto; a light-source controlling transistor for controlling power supplied to the light source by repeatedly switching whether or not the power is supplied to the light source; a capacitor having one end grounded and another end at which a potential is changed like a saw-tooth by charging and discharging of the capacitor; a capacitor controlling transistor for controlling a timing at which the charging and discharging of the capacitor is switched; and a comparator for comparing the potential at the other end of the capacitor to a reference voltage given thereto and controlling a timing at which the light-source controlling transistor is turned on or off and a timing at which the capacitor controlling transistor is turned on or off in synchronization with each other based on the comparison result.

Abstract: A lighting system includes a primary lamp circuit, an auxiliary lamp circuit, and an auxiliary controller. The auxiliary controller is connected between the primary lamp circuit and the auxiliary lamp circuit and is operable to sense a primary lamp circuit voltage. The auxiliary controller extinguishes an auxiliary lamp when the primary lamp circuit voltage exceeds a threshold voltage.

Abstract: A lighting system includes a primary lamp circuit, an auxiliary lamp circuit, and an auxiliary controller. The auxiliary controller is connected between the primary lamp circuit and the auxiliary lamp circuit and is operable to sense a primary lamp circuit voltage. The auxiliary controller extinguishes an auxiliary lamp when the primary lamp circuit voltage exceeds a threshold voltage.

Abstract: A power supply for light sources, particularly for fluorescent lamps and the like, comprising capacitive means (1) that are connected to the mains (9) and are adapted to supply rectifier means (2) for rectifying the mains current from AC to DC; and filter means (6) that are connected in output to the rectifier means (2) and are adapted to filter the rectified current for supplying power to a fluorescent lamp (8).

Abstract: The invention relates to a circuit arrangement for operating a high-pressure discharge lamp. A buffer capacitor is shunted by a branch which comprises a series circuit of a second capactor and a unidirectional element for blocking a current with which the second capacitor charges the buffer capacitor Re-ignition after a zero crossing of the low-frequency alternating current has a comparatively high amplitude so that the lamp re-ignites in a reliable manner.

Abstract: A load is provided, at all times when in operation, with a D.C. voltage having at least a minimum holding magnitude by: providing a source voltage having a peak magnitude greater than the holding magnitude; connecting the source voltage to the load only while the source voltage magnitude is greater than a preselected magnitude; charging from the peak source voltage magnitude an energy storage element while the load is connnected to the source voltage; energizing the load from the charged energy storage element whenever the source voltage magnitude is less than the preselected magnitude; increasing the effective impedance of the load whenever the load is energized by the storage element; and selecting the energy storage element to provide at least the holding voltage to the load during each time interval when the energy storage element is connected to the load.

Abstract: A ballast circuit for developing a predetermined desired D.C. voltage to enhance the operation of a gas discharge tube in a lighting unit of the type which also comprises an incandescent filament is disclosed. The ballast circuit operates from an applied 220 volt, 50 Hz alternating current (A.C.) source. The ballast circuit has an input stage comprised of a resistive capacitive network. The resistive capacitive network has values selected so as to reduce the applied 220 volt, 50 Hz excitation to a desired range for further development by the ballast circuit in providing a desired D.C. operational voltage for the gas discharge tube. Further, the ballast circuit provides means to prevent circuit malfunctions due to sudden changes in the applied A.C. source voltage. Still further, the ballast circuit provides a desired power factor operation of the gas discharge tube.

Abstract: The invention relates to an arrangement for starting and supplying a discharge lamp provided with cold electrodes. The lamp is shunted by a starter circuit which consists of a series arrangement of at least a capacitor and a controlled semiconductor switching element having a bidirectional thyristor characteristic.According to the invention a resistor with a positive temperature coefficient is connected in series with the capacitor and the controlled semiconductor switching element. If the lamp fails to ignite the device produces substantially no radio interference owing to the high-ohmic value of the PTC resistor produced by an increase in its temperature. Furthermore, a controlled semiconductor switching element having a low blocking voltage can now be used. Normal starting of the lamp is hardly affected by the PTC resistor.

Abstract: A starting device for a gas discharge lamp, to whose electrodes AC voltage is applied, comprises:A. first means electrically connected with at least one lamp electrode to apply to the lamp a transient voltage pulse which initially changes in amplitude in a polarity direction relatively in opposition to the polarity of the main voltage simultaneously supplied to the electrodes,B. said first means including circuitry to cause said pulse to thereafter change in amplitude in a polarity direction in aid of the polarity of the main voltage simultaneously supplied to the electrodes.

Abstract: An electronic ballast circuit for reducing the warm up time of high intensity discharge (HID) lamps wherein lamp current flow is abruptly reduced by a switching means responsive to load voltage variations upon attainment of power in an amount sufficient to activate the HID lamp.

Abstract: A starting device for a gas discharge lamp, to whose electrodes AC voltage is applied, comprises:a. first means electrically connected with at least one lamp electrode to apply to the lamp a transient voltage pulse which initially changes in amplitude in a polarity direction relatively in opposition to the polarity of the main voltage simultaneously supplied to the electrodes,b. said first means including circuitry to cause said pulse to thereafter change in amplitude in a polarity direction in aid of the polarity of the main voltage simultaneously supplied to the electrodes.