Abstract: A bias circuit for a switching power supply includes a rectifier that is connected to an AC power source and outputs a full wave rectified voltage Vs; a voltage divider, a diode, a first transistor, and a second transistor connected in parallel between Vs and ground; a capacitor connected between a first terminal of the second transistor and ground; and a node between the capacitor and the first terminal of the second transistor providing an output bias voltage Vcc from the bias circuit. A voltage from the voltage divider is provided to a gate of the first transistor, and the diode and a first terminal of the first transistor are connected to a gate of the second transistor.

Abstract: A fluorescent lamp (10) includes a tubular member or envelope (12) having an arc generating and sustaining medium (15) therein. As known, the tubular envelope (12) is constructed of a suitable glass, for example lime glass. An electrode (14) is provided in each end of the tubular member (12) and a phosphor coating (16) is applied to the interior surface (18) of the tubular member (12). A mercury dispenser (20) is situated within the tubular member (12). The mercury dispenser (20) includes a body (21) composed of a material selected from the group consisting of glass and ceramic materials. The body (21) is provided with a bore (22). A first material (24) capable of wetting mercury coats the bore. In a preferred embodiment the first material (24) is silver having a thickness between 0.1? and 8?. A quantity of mercury (26) is deposited in the bore (22) in contact with the first material (24).

Abstract: A current sensing circuit for sensing the current provided to LEDs by a constant current power source includes a resistive shunt in series with the load and a current mirror having a first leg connected to a first terminal of the resistive shunt and a second leg connected to a second terminal of the resistive shunt. Both legs of the current mirror are also connected to ground. The first leg provides a reference signal to the second leg, and the second log uses the reference signal and a voltage at the second terminal of the resistive shunt to provide a ground referenced output signal indicative of the current provided to the LEDs.

Abstract: A rear-loading LED module for a rear combination lamp is disclosed. One or more LEDs are mounted on a printed circuit board that electrically powers and mechanically holds them outside a faceted, parabolic reflector. Light emitted from the LEDs enters a light propagation region, formed between the reflective adjacent faces of two nested cylinders. The cylinders extend from the LEDs, outside the reflector, longitudinally through a hole at the vertex of the reflector, to the focus of the reflector. In some applications, the light propagation region may act as a beam homogenizer, so that light exiting the light propagation region may have roughly uniform intensity. Light from the light propagation region strikes an outwardly-flared reflector that directs it largely transversely onto the parabolic reflector. The parabolic reflector collimates the light and directs it longitudinally, through a transparent cover and out of the lamp.

Abstract: A rear-loading LED module for a rear combination lamp is disclosed. One or more LEDs are mounted on a printed circuit board that mechanically holds them at the focus of a faceted, parabolic reflector. Light from the LEDs diverges transversely and horizontally, and is collimated by the reflector, and the reflected collimated light is directed in a generally longitudinal direction out of the rear combination lamp, toward the viewer. The LED module itself is generally longitudinally oriented, and is insertable longitudinally into the interior of the reflector from a hole at the vertex of the reflector. The printed circuit board, an optional thermal pad adjacent to the printed circuit board, and a thermally conductive layer adjacent to the optional thermal pad are all generally planar layers, are all generally parallel to each other, and may optionally all have the same footprint. Together, the printed circuit board, the thermal pad and the thermally conductive layer may all form a generally planar ledge.

Abstract: A circuit (10) for powering a halogen lamp (20) comprises an inverter (100) and an output circuit (300). During operation, the inverter (100) and output circuit (300) provide a magnitude-limited current to the halogen lamp such that the lamp power during an initial period is substantially less than the lamp power during a steady-state operating period. Preferably, output circuit (300) is a non-isolated circuit that includes a current-limiting inductance, and inverter (100) includes a frequency control circuit (R2,C4,C7,Q3,R3,R5,C8) for operating the inverter at a higher frequency during the initial period so as to reduce stress upon the lamp filament and preserve the operating life of the lamp. The circuit (10) is especially suitable for powering low voltage halogen lamps.

Abstract: A luminaire comprising an output aperture having an input port and an output port, a radiation guide having an input port and an output port and an array of LEDs located at the input port of the guide. Light emitted by the LEDs is transmitted into the guide. The input port of the aperture operatively connects to the output port of guide and is positioned adjacent thereto so that a central plane of the output aperture is asymmetric relative to a central plane of the radiation guide.

Abstract: An incandescent lamp includes a lamp voltage conversion circuit within the lamp and connected to a lamp terminal, where the voltage conversion circuit converts a first line voltage at the lamp terminal to a second RMS load voltage usable by a light emitting element of the lamp. The voltage conversion circuit includes a triac phase-controlled dimming circuit, which in turn includes a voltage controlled resistor that varies a resistance in the phase-controlled dimming circuit as the first voltage varies so as to maintain the second voltage substantially constant. The voltage conversion circuit may be an integrated circuit that is in the lamp base and connected between the lamp terminal and the light emitting element.

Abstract: An electronic ballast (20) for powering at least one gas discharge lamp (30) comprises a self-oscillating half-bridge inverter (200?) having an inverter startup circuit (286,288,290) that does not require a voltage breakdown device, such as a diac. Inverter startup circuit (286,288,290) comprises a first resistor (286), a second resistor (288), and a capacitor (290).

Abstract: A ballast (10?) for powering at least one gas discharge lamp (32) comprises an inverter (100) and an output circuit (200?). Output circuit (200?) includes an output transformer (230) and output connections (202, . . . ,210) for connection to one or more lamps (32,34). A secondary winding (234) of output transformer (230) includes a tap connection (240). A voltage-limiting impedance (260) is coupled between the tap connection (240) and earth ground (80). Tap connection (240) is positioned, and voltage-limiting impedance (260) is sized, so that the voltage between earth ground (80) and any of the output connections (202, . . . ,210) remains below applicable limits as dictated by regulatory and/or safety requirements.