Abstract: An electronic ballast (100) for powering at least one gas discharge lamp (30) at two light levels includes a full-wave rectifier circuit (120) and a detector circuit (200). Detector circuit (200) provides an output voltage that is dependent on the states of two on-off switches (S1,S2), but that is substantially unaffected by typical X capacitances that are present between the hot and neutral input connections of the ballast.

Abstract: In an operating method for a lighting system and a lighting system in which a readiness command is provided, in response to such readiness command a ballast drives a discharge lamp in such a way that it heats the electrodes further if the discharge lamp is not burning, so that a controller can use a switch-on command to reignite the discharge lamp without delay by means of a preheating time.

Abstract: FA ballast (20) for powering a gas discharge lamp (70) comprises an inverter (200) and an arc protection circuit (600). Arc protection circuit (600) monitors an electrical signal within the ballast. In response to occurrence of a disturbance in the signal, such as what occurs during output arcing, arc protection circuit (600) disables the inverter (200) for a timed shutdown period. Arc protection circuit (600) provides a timed starting period for igniting the lamp, during which time any disturbance in the electrical signal is essentially ignored and inverter (200) is allowed to continue to operate. Arc protection circuit (600) also provides a restart function for periodically attempting to ignite and operate the lamp. Arc protection circuit (600) is preferably realized using a timer integrated circuit (U1) with associated discrete circuitry, and may be adapted for use with ballasts having self-oscillating or driven type inverters.

Abstract: An in-line coaxial cable connector (10) has an electrically insulating member (32) that is fitted over a first electrical contact (22) and has a first end (32a) and a second end (46) extending over a second end (26) of the first electrical contact (22). The terminus of the second end (46) includes a lip (48) forming an alignment area for the reception of a mating electrical contact. The lip (48) protects the contact beams of the contact (22) and eliminates the possibility of the contact (22) mismating with its complement on a mating connector.

Abstract: A right-angled connector comprises a subassembly (10) including an electrically conductive member or ground shell (12) having a longitudinal section (12a) and a transverse section (12b). The longitudinal section (12a) is provided with a longitudinal axis (13) and at least a portion (14) of the member (12) provides a cylindrical, hollow end (16). A trough (18) is formed in the member (12) to accommodate an electrically conductive contact pin (18a) and at least one leg (19) is provided on member (12) extending in a direction transverse to the longitudinal axis (13). In a preferred embodiment the member (12) has four legs (19), as shown in FIGS. 2 and 5, which in the final construction will provide the ground connections for the connector. Member (12) can be die cast zinc. Member (12) additionally is provided with an integral electromagnetic interference shield in the form of oppositely disposed wings (100, 102), which project from the hollow cylindrical end 16.

Abstract: A ballast (10) for powering at least one gas discharge lamp (52) from a three-phase AC voltage source (30) comprises a three-phase rectifier circuit (200), a high frequency filter capacitor (300), and a high frequency inverter (400). Preferably, three-phase rectifier circuit (200) is implemented by a six-diode bridge, and high frequency filter capacitor (300) can be realized by a film capacitor or a ceramic capacitor. Ballast (10) provides a high power factor and low total harmonic distortion without requiring a dedicated power factor correction circuit. Other benefits of ballast (10) include enhanced efficiency, longer life, and lower inrush current.

Abstract: A ballast (20, 20?) includes a rectifier circuit (100), a boost converter (200, 200?), an inverter (300), an output circuit (400), and an inverter startup circuit (600). Inverter startup circuit (600) is coupled between boost converter (200) and inverter (300). During operation, inverter startup circuit (600) provides a delay period between startup of boost converter (200) and startup of inverter (300) so that startup of inverter (300) is delayed until at least such time as the DC rail voltage provided by boost converter (200) approaches its steady-state operating level. This ensures that the ballast (20,20?) provides an output voltage that is sufficiently high to ignite a lamp (40) in a preferred manner, with little or no glow current and a fast strike time.

Abstract: A ballast (10) for powering a gas discharge lamp load (30) comprises an inverter (100), an output circuit (200), and a fault detection circuit (300). During operation, fault detection circuit (300) monitors a first signal and a second signal within output circuit (300) and sets a fault threshold in dependence on the second signal. The second signal is indicative of the type of lamps in the load (30). In response to the first signal exceeding the fault threshold, fault detection circuit (300) issues a shutdown command directing the inverter (100) to cease operation.

Abstract: A two-piece second anode button for a cathode ray tube has: a first portion defined by a cup-shaped can having a seating area at its widest part and a second portion comprising and a planar annulus fixed in said seating area, said first portion comprising a nickel-iron alloy having a composition of about 47 wt. % nickel, about 6 wt. % chromium and the balance iron and said second portion comprising a ferritic stainless steel alloy having a chromium content of about 10 to about 28% by weight.

Abstract: A ballast (100) includes an inverter (140,144,146) and a protection circuit that prevents excessive lamp-to-earth-ground fault current. The protection circuit includes a transformer (202,204,206,208,210) and an inverter disable circuit (300). The transformer measures a first current going out of one set of ballast output terminals (106,108) and a second current going into another set of ballast output terminals (206,208). In response to a substantial imbalance between the first current and the second current, inverter disable circuit (300) terminates inverter switching. Preferably, protection circuit further includes a restart timer circuit (400) that, following termination of inverter switching in response to a fault condition, prevents the inverter from restarting for a predetermined delay period.

Abstract: A ballast (100) having an inverter (110,120,122) and a direct current blocking capacitor (130) coupled in series with a ballast output (108) includes a control circuit (140) for providing adaptive end-of-lamp-life protection. During operation, control circuit executes the steps of measuring (208) and storing (210) a reference value for the voltage across the DC blocking capacitor (130), monitoring (308,310) the voltage across the DC blocking capacitor (130), and protecting (312) the inverter and lamp sockets in response to the voltage across the DC blocking capacitor departing from the reference value by more than a predetermined threshold amount.

Abstract: A dimming control system includes a first circuit (100) and a second circuit (400). First circuit (100) is coupled in series with the AC line source (10) and receives brighten and dim commands from a user. The brighten and dim commands are communicated to second circuit (400) by momentarily altering the AC voltage waveforms observed by second circuit (400). Second circuit (400) provides an adjustable output signal that is coupled to inverter circuitry within an electronic dimming ballast. The output signal is adjusted by the second circuit (400) in dependence on the observed AC voltage waveforms.

Abstract: A ballast (10,20) for powering a gas discharge lamp load (30) comprises a protection circuit (300,600) operable to monitor an electrical signal (40) in the ballast and disable the ballast for at least a predetermined period of time in response to a disturbance wherein at least a portion (44) of the electrical signal (40) exhibits a time-rate-of-change that exceeds the time-rate-of-change of the signal during normal operation of the ballast and gas discharge lamp load. Protection circuit (300,600) is capable of disabling the ballast within a response time that is less than twice the period of the electrical signal. In a preferred embodiment that is suitable for ballasts with driven-type inverters, protection circuit (300) comprises a latching device (310) and a triggering circuit (330). In a preferred embodiment that is suitable for ballasts with self-oscillating type inverters, protection circuit (600) comprises a pull-down circuit (640) and a negative voltage source (610).

Abstract: A dimming ballast (100) for a high-intensity discharge lamp (10) includes an ignitor (120), a control circuit (140), and a dimming interface (160) for connection to an external dimming controller (30). Following lamp replacement (10), external dimming controller (30) receives a user relamp command and, in response, sends a special relamp signal to dimming interface (160). In response to the special relamp signal, dimming interface (160) communicates with control circuit (140), which directs ignitor (120) to provide high voltage pulses for igniting the replaced lamp. In an alternative embodiment, an external control device such as a triac dimmer (40) receives a user relamp command following lamp replacement and, in response, sends a special relamp signal to a control circuit (240), which directs ignitor (220) to provide high voltage pulses for igniting the replaced lamp.

Abstract: A ballast (100) and method for regulating power in a high pressure discharge lamp (130) is disclosed. In a preferred embodiment, ballast (100) comprises a microcontroller (102), a buck converter (110), and an inverter (120). Microcontroller (102) monitors a signal representative of the lamp voltage and sets a current in the lamp based upon the monitored signal via control of a buck current provided by the buck converter (110). A method for regulating power in a high pressure discharge lamp is also described. The method comprises steps of detecting (202) a voltage at the lamp and setting (204) a current in the lamp based upon the detected voltage.

Abstract: A ballast (20′) for powering a plurality of gas discharge lamps (12,14,16) includes a load-adaptable charge pump power factor correction arrangement (62,64,66,100,200,300) for feeding back a high frequency current having a magnitude that is dependent on the number of operating lamps.

Abstract: A ballast (10) for powering a gas discharge lamp load includes an inverter (200) and a protection circuit (400) for preventing start up of the inverter (200) in response to a ground fault condition wherein one or more of the ballast output connections (302,306) is coupled to earth ground.

Abstract: A special dual fuel method and system is provided to enhance vehicle performance and fuel consumption as well as to accommodate a smooth transition when operating the engine on different fuels, such as gasoline or liquified petroleum gas (LPG). When the engine is operated on a different fuel, a filtered oxygen (O2) signal is transmitted to an engine control unit (ECU) which can regulate operation of the gasoline shutoff valve and an LPG valve and responds to the filtered O2 signal and the type of fuel, i.e. mode of operation, selected for the dual fuel engine.

Abstract: A circuit for controlling current during run-up of a high pressure discharge lamp (140) comprises a buck converter (120) for generating a buck current to drive the high pressure discharge lamp and a control circuit (202) coupled to the buck converter (120) for varying the duty cycle of the buck current during run-up is disclosed. A method for controlling current in an electronic ballast during run-up of a high pressure discharge lamp comprises steps of detecting (501) lamp ignition, providing (502) a buck current to drive the lamp, and varying (504) the duty cycle of the buck current during run-up to control (506) the current in the lamp is also disclosed.

Abstract: A ballast (10) for powering a gas discharge lamp includes a lamp-out detection circuit (300) that quickly responds to a lamp-out condition. Lamp-out detection circuit (300) receives a portion of the lamp current and provides a detection voltage. The detection voltage remains at a first average level while the lamp is conducting current in a normal manner, but quickly decreases below a second level if the lamp ceases to conduct current. In a preferred embodiment, ballast (10) includes an inverter (100) and a resonant circuit (210,220) that are normally operated at a high frequency. The detection voltage is coupled to an enable input (112) of an inverter drive circuit (110), and the inverter (100) is either shut off or operated in a low-power mode within less than ten high frequency cycles after occurrence of a lamp-out condition.