摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A continuous mode electronic ballast operates a lamp. A buck converter is configured to generate a direct current (DC) bus voltage at buck converter output. An inverter circuit is operationally coupled to the buck converter output, and configured to receive the DC voltage and convert the DC voltage into an AC voltage to drive the lamp. A short circuit protection circuit is operationally coupled to the buck converter output to sense the DC bus voltage, compare the sensed DC voltage to a predetermined threshold and, based on the comparison, shut down the inverter circuit.
摘要:
The present invention provides a ballast circuit powered by a system power source. The ballast, in operative connection with the system power source, is an inverting type of ballast designed to generate an asymmetric alternating lamp input current on a lamp input line. Further, a gas discharge lamp is in operative connection to the lamp input line configured to receive the asymmetric alternating current. The inverting circuit of the ballast is configured with complementary switches configured to have unequal on times, thereby producing an asymmetric lamp input current. A DC blocking capacitor is provided to block any DC current from the lamp input line. The asymmetric alternating lamp input current eliminates visual striations otherwise occurring in the lamp.
摘要:
A ballast circuit including a power factor correction circuit with an alterable d.c. bus charging rate is provided. The power factor correction circuit selectively alters the d.c. bus charging rate such that, during a startup period for the ballast circuit, the charging rate is faster than during a steady-state period. The ballast circuit including a bridge rectifier, a power factor correction circuit, a bus capacitor, and at least one inverter. The power factor correction circuit including a power factor controller, a semiconductor switch operationally coupled to an output signal of the power factor controller, a selectively alterable impedance network operationally coupled to an output of the semiconductor switch and operationally coupled to an input signal of the power factor controller, and an impedance network control circuit operationally coupled to the impedance network to selectively alter the impedance network.
摘要:
A multiple integrated lamp system is powered by a power source. The system includes a first integral lamp having lamp electronics and a lamp integrated as a single unit, and a second integral lamp having lamp electronics in a lamp also integrated as a single unit. A first connection wire is connected from a first pin of the first integral lamp to a second pin of the first integral lamp. A second connection wire is connected from a first pin of the second integral lamp to a second pin of the second integral lamp. A first power line is connected at a first end to the power source, at a second end to a third pin of the first integral lamp, and at a third end to a third pin of the second integral lamp. Further, a second power line is connected at a first end to the power source, at a second end to a fourth pin of the second integral lamp, and a third end to a fourth pin of the second integral lamp.
摘要:
A power converter circuit is powered by a power source thereby generating a power line voltage. A rectifier is configured to rectify the power line voltage and generate a pulsating d.c. voltage with a frequency which is twice a frequency of the power line voltage. A gate drive circuit is designed to receive the pulsating d.c. voltage. The gate drive circuit drives a pair of switches which are controlled to invert the pulsating d.c. voltage, without use of level shifting. The gate drive circuit further includes a driving inductor, a timing inductor and a timing capacitor serially connected to each other and connected to the switches to control operation of the switches. The transformer, including a first transformer winding and a second transformer winding, and a capacitor are designed to receive an output signal from the switches. A lamp is connected to receive the driving signals from the transformer winding through a tap, where the tap attenuates the signal developed across the transformer winding.
摘要:
A ballast circuit 10 for a gas discharge lamp 14, incorporates a shutdown circuit 12 for limiting voltage output of a d.c.-to-a.c. converter 21. The shutdown circuit includes a pair of terminals 66 and 68 connecting across an inductor 48 in order to sense the inductive voltage of the d.c.-to-a.c. converter 21. A rectifier network 70-76 receives the inductor voltage and generates a full-wave rectified voltage. A latch 84 is arranged to receive the rectified voltage and to enter an active state when the rectified voltage is above a pre-determined value. A time delay circuit 118 located between the rectifier network 70-76 and the latch 84 provides an adjustable delay time prior to activation of the latch network. Upon activation of the latch, the inductor voltage is decreased and the ballast circuit 10 is taken out of resonance thereby lowering the voltage and current applied to the resonant circuit 28.
摘要:
A ballast circuit for a gas discharge lamp includes a d.c.-to-a.c. converter circuit with circuitry for coupling to a resonant load circuit, for inducing a.c. current therein. The converter circuit comprises a pair of switches serially connected between a bus conductor at a d.c. voltage and a reference conductor, the voltage between a reference node and a control node of each switch determining the conduction state of the associated switch. The respective reference nodes of said switches are connected together at a common node through which said a.c. current flows, and the respective control nodes of the switches are connected together. A gate drive arrangement is provided for regeneratively controlling the first and second switches. The arrangement comprises a feedback circuit for providing a feedback signal representing current in the load circuit; a coupling circuit including an inductor for coupling the feedback signal to the control nodes; and a first bidirectional voltage clamp connected between the common node and the control nodes. A second bidirectional voltage clamp is coupled across the inductor in such manner as to limit the positive and negative voltage excursions across the inductor.