Abstract: A dimming control system includes a first circuit (100) and a second circuit (200). 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 (200) by momentarily altering the AC voltage waveforms observed by second circuit (200). Second circuit (200) provides an adjustable dimming control voltage that is coupled to existing dimming control circuitry within an electronic dimming ballast. The dimming control voltage is adjusted by the second circuit (200) in dependence on the observed AC voltage waveforms.

Abstract: A ballast (10) for powering a gas discharge lamp (20) having heatable filaments (22,24) includes a filament heating and protection circuit (300) that provides preheating of the filaments, efficiently reduces the filament heating power after the lamp ignites, quickly responds to removal or failure of the lamp in order minimize power dissipation in the ballast, and operates a replaced lamp without requiring cycling of the power to the ballast. In a preferred embodiment, filament heating and protection circuit (300) includes a transformer (400), a switching circuit (600), a turn-on circuit (700), and a lamp-out detection circuit (800).

Abstract: A dimming ballast apparatus comprises at least one power line dimming control input and at least one non-power-line dimming control input. In a preferred embodiment, the apparatus comprises a firing-angle-to-pulse-width-modulation converter responsive to the power line dimming control input, a voltage-to-pulse-width-modulation converter responsive to the non-power-line dimming control input, a low-pass filter responsive to the firing-angle-to-pulse-width-modulation converter and the voltage-to-pulse-width-modulation converter, and a dimming ballast circuit having a dim level command input responsive to the low-pass filter.

Abstract: A method (100) for closing a motor-driven window comprises the steps of determining (102) a window gap, and raising (104) the window at a speed dependent upon the window gap. The speed is selected based on the window gap and is reduced as the window gap approaches a pinch region such that the pinch-force is limited to a safe value. A vehicle power-window system (400) comprises a window assembly (410), a battery (420), an electric motor (430), a mechanical assembly (440), and a control circuit (450). Control circuit (450) monitors the window gap and supplies drive voltage to the electric motor in dependence on the window gap, so as to control the speed of the window in accordance with the disclosed method (100). Preferably, control circuit (450) includes a regulator circuit (460) and a processor (470), and the drive voltage is substantially unaffected by at least some changes in the battery voltage.

Abstract: A multi-part reactive device preferably includes a substrate with a first conductive area and a second conductive area. A first conductive element with a first terminal is connected to the first conductive area. The first conductive element has a second terminal connected to the second conductive area. A current loop is formed extending from the first conductive area, through the first terminal, through the second terminal, to the second conductive area. A magnetically-effective core member is captivated by the first conductive element to the substrate between the first conductive area and the second conductive area and encircles the current loop. The first conductive area, the first conductive element, the magnetically-effective core member, and the second conductive area form a first magnetic circuit. Additional magnetic circuits can be formed by adding additional conductive patterns and additional conductive elements.

Abstract: A regulating circuit for a transformer is provided. The circuit includes at least a primary stage in association with a primary coil of a transformer and a secondary stage in association with a secondary coil of the transformer. Switching means are circuited to control current through the primary stage and a comparing means is provided in communication with the switching means. The comparing means compares voltage in the secondary stage with a desired value, and operates to open and close the switching means in accordance with this determination to result in a desired output voltage. Alternatively, the comparing means compares the voltage at the secondary stage with the voltage input to the primary stage. The comparing means operates to open the switching means when the voltage of the primary stage exceeds the input voltage. A method is also disclosed that includes the steps of determining a voltage at the primary stage circuit, determining a voltage at the secondary input, and comparing the voltages.

Abstract: A flexible circuit board and a method for making a flexible circuit board. The flexible circuit board (10) is formed from a substantially rigid material and includes a first portion (12) and a second portion (14) coupled by a bend region (16). The bend region (16) includes at least one bend (40, 52) having a radius less than 120 mils.

Abstract: A method and system for monitoring air pressure or operational status of at least one particular tire of a vehicle facilitates ready identification of a relative mounting position of the particular tire. At least one pressure indicating signal is received (110 of FIG. 8) and is associated with a particular tire mounted at an unknown relative position on a vehicle. Physical parameter data are obtained (112) indicating physical parameter measurements at the different tires of a vehicle. The obtained physical parameter data are evaluated (114) to identify the relative mounting position of the particular tire on the vehicle. Accordingly, an operator of the vehicle may be provided with an indication (130) that an air pressure of a particular tire is less than a proper air pressure so that peak vehicle performance and necessary maintenance may be obtained. Even if the indication informs that the pressure is normal, the operator is reassured that the tires are functioning properly.

Abstract: A ballast housing (10) comprising a base (100), a cover (200), an input connector (300), and an output connector (400). Input connector (300) and output connector (400) serve as end-caps of the housing (10), and provide solderless connections between external wires and the ballast circuitry. The base (100) has formed edges (132,142) that are received into corresponding channels (242,252) in the cover (200). Tabs on the connectors (300,400) and corresponding apertures in the base (100) and cover (200) provide a secure ballast housing that accommodates efficient provision of input and output wires.

Abstract: An electronic ballast (10) for fluorescent lamps includes a rectifier circuit (100), a boost converter (200), and an inverter (500). The boost converter (200) includes a boost control circuit (400) and a shifting circuit (300). The shifting circuit (300) provides filament preheating by maintaining the boost output voltage at a first level for a predetermined delay period following startup of the boost converter, and then increasing the boost voltage to a second level upon completion of the delay period in order to ignite and operate the lamps. In a preferred embodiment, shifting circuit (300) comprises a shunt circuit (320) and a time delay circuit (360), and inverter (400) is a series resonant half-bridge inverter.

Abstract: An electronic ballast (10) for powering at least one gas discharge lamp (30) includes a rectifier circuit (100), a line blocking rectifier (220), a bulk capacitor (240), an inverter (300), an output circuit (400), and a charging circuit (500). Charging circuit (500) is coupled between the output circuit (400) and the bulk capacitor (240) and provides operating current to the bulk capacitor (240). Charging circuit (500) also protects lamp life by preventing excessive flow of DC current in the lamp (30) following application of AC power to the ballast (10). In a preferred embodiment, charging circuit (500) includes a DC blocking capacitor (510), a lamp current blocking rectifier (530), and a charging rectifier (540).

Abstract: An electronic ballast (100) for powering at least one gas discharge lamp (10) comprises an inverter (200) and an output circuit (300). Output circuit (300) comprises a resonant inductor (310), a resonant capacitor (330), a DC blocking capacitor (360), a first rectifier (350), and a second rectifier (370). Output circuit (300) prevents excessive current flow and power dissipation in the event of lamp removal or failure, and provides automatic ignition following lamp replacement. In an alternative embodiment, a ballast (160) for powering two lamps (10,20) includes a pair of modified output circuits (500,600) and a ground-referenced lamp return wire (504) for accommodating conventional instant-start type wiring.

Abstract: An electronic power supply (10) comprising a rectifier circuit (100) and a voltage converter circuit (200). Voltage converter circuit (200) comprises a first inductor (220), a second inductor (230), an electronic switch (240), a control circuit (300), a first rectifier (250), a second rectifier (260), a first capacitor (270), and a second capacitor (280). First inductor (220) and second inductor (230) may be implemented either as separate inductors or as coupled inductors. Power supply (10) efficiently provides a high output voltage with greater efficiency than conventional boost converters.

Abstract: A method (100) of controlling an inverter in an electronic ballast for at least one gas discharge lamp protects the inverter from damage due to lamp fault conditions, and provides enhanced noise immunity and multiple ignition attempts for low-temperature lamp starting. The method (100) includes repeating a filament preheating step and a frequency shifting step up to a predetermined number of times in order to facilitate lamp ignition under low-temperature conditions and to verify the legitimacy of a detected lamp fault.

Abstract: An electronic ballast (300) for powering at least one gas discharge lamp (10) includes an inverter (400), an output circuit (700), a lamp fault detection circuit (800), and an inverter control circuit (500). Ballast (300) operates according to an inverter control method (100) that includes repeating a filament preheating step and a frequency shifting step up to a predetermined number of times in order to facilitate lamp ignition under low-temperature conditions and to verify the legitimacy of a lamp fault. Inverter control circuit (500) is well-suited for implementation as a custom integrated circuit. Ballast (300) optionally includes an overcurrent detection circuit (820') with an adjustable lamp fault detection threshold that provides decreased sensitivity during lamp starting and enhanced protection after lamp ignition.

Abstract: An electronic power supply (100) receives power from an AC source (10) and supplies power to a load (20) that is referenced to earth ground (30). Power supply (100) comprises a power converter (200) and a voltage regulator (400). Power converter (200) draws a ground leakage current from AC source (10) and is capable of providing a steady-state output current having an average value that is greater than that of the ground leakage current. Voltage regulator (400) limits the output voltage of the power converter (200) to a predetermined level. In a preferred embodiments power converter (200) is implemented as a self-oscillating converters and power supply (100) draws a ground leakage current that is sufficiently small to meet regulatory limits and to avoid tripping of conventional ground-fault interrupters.

Abstract: An electronic ballast (10) comprising an AC-to-DC converter (100), an inverter (200), an output circuit (400), a high-voltage detection circuit (500), and a no-load detection suit (600). The inverter (200) includes an inverter control circuit (300) that monitors the lamp(s) via the high-voltage detection circuit (500) and the no-load detection circuit (600), and that terminates inverter switching in response to various lamp-fault conditions such as "diode-mode" behavior. Inverter control circuit (300) also provides for automatic ignition of a replaced lamp and may be economically implemented as a single integrated circuit.

Abstract: An electronic ballast (200) includes a rectifier circuit (20), a clamp inductor (44), an electronic switch (62), a control circuit (60) for driving the electronic switch (62), an energy storage capacitor (34), a first diode (38), a second diode (50), a clamping capacitor (58), and an output circuit (80). In a preferred embodiment, the rectifier circuit (20) includes a full-wave diode bridge (22) and a high frequency filter capacitor (24), and the output circuit (80) has a resonant inductor (82), a resonant capacitor (92), and a DC blocking capacitor (98). The ballast (200) provides power factor correction, low in-rush current, and high frequency power for fluorescent lamps, but requires only a single electronic switch (62) and a single clamp inductor (44).

Abstract: An electronic ballast (100) for powering at least one gas discharge lamp (10) comprises an inverter (300), an output circuit (400), and a switching circuit (500). Output circuit (400) includes a resonant inductor (440) and a resonant capacitor (460). Switching circuit (500) is coupled between the resonant capacitor (460) and an AC ground node such as circuit ground node (60), and is operable to effectively disconnect the resonant capacitor (460) after the lamp (10) ignites, thereby eliminating circulating current and significantly enhancing ballast energy efficiency. Switching circuit preferably comprises an electronic switch (600) and a pulse circuit (700), and optionally includes a diode matrix for use in ballasts for powering two or more lamps. In one embodiment, pulse circuit (800) monitors for lamp replacement and provides automatic ignition of a replaced lamp.