Abstract: An electronic OLED driver apparatus is presented, which includes a DC-DC converter stage with a waveform generator generating converter setpoints with profiles having minimum rise time and fall time values.

Abstract: A dimmable ballast and methods are presented in which the operating frequency of a self-oscillating inverter is controlled according to a sensed lamp current for dimming control or cathode heating, and an AC bus voltage of the inverter is controlled to be at or below a voltage threshold value to prevent over driving operating lamps when one or more lamps are being replaced.

Abstract: An electronic OLED driver apparatus is presented, which includes a DC-DC converter stage with a waveform generator generating converter setpoints with profiles having minimum rise time and fall time values.

Abstract: A ballast with end-of-life (“EOL”) protection is presented in which the voltage across a lamp at EOL is controlled to prevent the lamp from overheating, while the voltage across the lamps not at EOL is maintained to allow normal operation of those lamps, and when a new lamp is added to the ballast, the AC voltage across all lamps is controlled to allow ignition of the newly added lamp without cycling the power of the ballast.

Abstract: In a lighting ballast there are typically several discrete components that combine to take an external AC signal and convert it to a DC signal, and back to an AC signal for powering a lamp. Several of these components can be housed on an application specific integrated circuit. By placing switching transistors (20, 22) their companion diodes (34, 36), and a rectifying circuit (52) on a monolithic integrated circuit (60), the ballast circuit as a whole is made more reliable and robust and can be manufactured at a lower cost than if discrete components had been used.

Abstract: A ballast with end-of-life (“EOL”) protection is presented in which the voltage across a lamp at EOL is controlled to prevent the lamp from overheating, while the voltage across the lamps not at EOL is maintained to allow normal operation of those lamps, and when a new lamp is added to the ballast, the AC voltage across all lamps is controlled to allow ignition of the newly added lamp without cycling the power of the ballast.

Abstract: A power converter circuit converts an AC line signal to a DC signal for powering an organic light emitting diode. The circuit uses only capacitive elements to limit current to the LED. Inductive and resistive elements are not included in the circuit to limit current. The absence of inductive components eliminates electromagnetic interference generated by the circuit and avoids circuit components magnetically coupling to one another. The circuit includes complementary MOSFET switches that alternately conduct to convert the AC line voltage into a DC current for powering the LED.

Abstract: A lighting ballast (10) includes an inverter portion (12) and a resonant portion (14). During a preheat phase, a filament transformer (110) supplies preheat glow currents to lamp cathodes. Also during the preheat phase, the filament transformer boosts the oscillation frequency of the inverter portion (12) to a frequency above a resonant frequency of the resonant portion (14). Once the lamp cathodes are sufficiently heated, the filament transformer (110) is removed from the circuit and the inverter (12) is allowed to start oscillating. A feedback network (150) monitors a high frequency bus (26) and provides input to a shunt regulator (170). The shunt regulator drives the gate of a switch (128) of a bias network (126) and adds or removes the filament transformer (110) to the circuit depending on the conductive state of the switch (128).

Abstract: In an instant start ballast, dimming control is provided over a range of operation in which lamps driven by the ballast do not require external cathode heating. An interface circuit (92) includes a winding (90) that is inductively coupled to windings (68, 70) of an inverter circuit (12). The interface circuit (92) also includes a variable impedance in parallel with the winding (90) where the variable impedance includes a transistor (96) and a Zener diode (98). By varying an input voltage across control leads (94), the apparent inductance of the winding (90) is varied. This variance affects the switching frequency of the inverter circuit (12) affecting the frequency of a drive signal provided to the lamps. Thus the instant start ballast can be dimmed without use of multiple ballasts and/or external cathode heating.

Abstract: A dimmable ballast and methods are presented in which the operating frequency of a self-oscillating inverter is controlled according to a sensed lamp current for dimming control or cathode heating, and an AC bus voltage of the inverter is controlled to be at or below a voltage threshold value to prevent over driving operating lamps when one or more lamps are being replaced.

Abstract: A circuit or combined ballast for driving a fluorescent lamp and at least one light emitting diode (LED) includes an integrated driver circuit having an alternating current (AC) circuit that includes at least one ballast coil for driving the fluorescent lamp and a direct current circuit for driving the LED having a secondary winding inductively coupled with the fluorescent lamp ballast coil for driving the LED. A method of driving a lamp assembly includes at least one fluorescent lamp and at least one light emitting diode (LED) and a combined driver circuit for supplying both the fluorescent lamp and the LED.

Abstract: The present application discloses a method and apparatus for providing an isolated set point from an input signal. The set point can control the amount of power applied to a lamp via a lamp ballast. An AC output signal from the ballast powers a dimming circuit. The AC signal is coupled across an isolation transformer and subsequently converted into a DC signal. This DC signal is loaded by a variable resistor, which creates a voltage differential across the resistor. This voltage differential is then seen across DC input terminals of the ballast, and it is across the DC input terminals that the set point is created. By varying the value of the resistor, the ballast set point is varied ultimately changing the power that is applied to the lamp by the ballast.

Abstract: The embodiment disclosed herein relates to a lighting system that includes an auxiliary lighting circuit for use with an electronic HID ballast. The lighting system comprises a power supply configured to provide power to a high intensity discharge (HID) lamp via an electronic ballast and a ballast power sensing component configured to determine the amount of power drawn by the electronic ballast and to convert this power drawn by the electronic ballast to a scaled voltage that is representative of the power drawn by an HID ballast. A lamp driver component is configured to provide power to an auxiliary lamp via the same power supply when the scaled voltage reaches a triggering threshold. A voltage regulation component is configured to regulate the power delivered to the auxiliary lamp such that the auxiliary lamp power stays within a predefined range.

Abstract: A lighting ballast (10) includes an inverter portion (12) and a resonant portion (14). During a preheat phase, a filament transformer (110) supplies preheat glow currents to lamp cathodes. Also during the preheat phase, the filament transformer boosts the oscillation frequency of the inverter portion (12) to a frequency above a resonant frequency of the resonant portion (14). Once the lamp cathodes are sufficiently heated, the filament transformer (110) is removed from the circuit and the inverter (12) is allowed to start oscillating. A feedback network (150) monitors a high frequency bus (26) and provides input to a shunt regulator (170). The shunt regulator drives the gate of a switch (128) of a bias network (126) and adds or removes the filament transformer (110) to the circuit depending on the conductive state of the switch (128).

Abstract: In a lighting ballast there are typically several discrete components that combine to take an external AC signal and convert it to a DC signal, and back to an AC signal for powering a lamp. Several of these components can be housed on an application specific integrated circuit. By placing switching transistors (20, 22) their companion diodes (34, 36), and a rectifying circuit (52) on a monolithic integrated circuit (60), the ballast circuit as a whole is made more reliable and robust and can be manufactured at a lower cost than if discrete components had been used.

Abstract: The present application discloses a method and apparatus for providing an isolated set point from an input signal. The set point can control the amount of power applied to a lamp via a lamp ballast. An AC output signal from the ballast powers a dimming circuit. The AC signal is coupled across an isolation transformer and subsequently converted into a DC signal. This DC signal is loaded by a variable resistor, which creates a voltage differential across the resistor. This voltage differential is then seen across DC input terminals of the ballast, and it is across the DC input terminals that the set point is created. By varying the value of the resistor, the ballast set point is varied ultimately changing the power that is applied to the lamp by the ballast.

Abstract: In an instant start ballast, dimming control is provided over a range of operation in which lamps driven by the ballast do not require external cathode heating. An interface circuit (92) includes a winding (90) that is inductively coupled to windings (68, 70) of an inverter circuit (12). The interface circuit (92) also includes a variable impedance in parallel with the winding (90) where the variable impedance includes a transistor (96) and a Zener diode (98). By varying an input voltage across control leads (94), the apparent inductance of the winding (90) is varied. This variance affects the switching frequency of the inverter circuit (12) affecting the frequency of a drive signal provided to the lamps. Thus the instant start ballast can be dimmed without use of multiple ballasts and/or external cathode heating.

Abstract: A circuit or combined ballast for driving a fluorescent lamp and at least one light emitting diode (LED) includes an integrated driver circuit having an alternating current (AC) circuit that includes at least one ballast coil for driving the fluorescent lamp and a direct current circuit for driving the LED having a secondary winding inductively coupled with the fluorescent lamp ballast coil for driving the LED. A method of driving a lamp assembly includes at least one fluorescent lamp and at least one light emitting diode (LED) and a combined driver circuit for supplying both the fluorescent lamp and the LED.

Abstract: For safety reasons, industrial lighting fixtures are required to have backup lighting systems so that if the primary lights should fail, there will still be enough light to ensure safe maneuvering. Typically these backup lighting systems have their own power or drive source. The present application contemplates a lighting ballast circuit that is able to power a primary high intensity discharge (HID) lamp and is also able to power an auxiliary lamp in the event of temporary or permanent failure of the HID lamp.

Abstract: A power converter circuit converts an AC line signal to a DC signal for powering an organic light emitting diode. The circuit uses only capacitive elements to limit current to the LED. Inductive and resistive elements are not included in the circuit to limit current. The absence of inductive components eliminates electromagnetic interference generated by the circuit and avoids circuit components magnetically coupling to one another. The circuit includes complementary MOSFET switches that alternately conduct to convert the AC line voltage into a DC current for powering the LED.