摘要:
Circuits, and methods of using same, are disclosed for pulse operating a sodium vapor lamp and, in response to gating pulses applied to a resonant ballast, the lamp ignites to develop a quasi-resonant bidirectional current waveform through the lamp, the shape of which is controlled to suppress the excitation of acoustic resonant nodes in the lamp. The quasi-resonant bidirectional current waveform oscillates at a prescribed frequency and contains a first group of harmonics, the harmonic content of which is outside any acoustic frequency region associated with the lamp, and further contains a second group of harmonics having a harmonic content which coincides with such acoustic frequency region. The current waveform is caused to decay substantially at the time of ignition of the lamp to quickly reduce the magnitude of the second group of harmonics to thereby suppress excitation of the acoustic frequency region and prevent arc instability in the lamp.
摘要:
A high voltage split core transformer and method of assembling same is provided by which the coupling factor is improved. A split core assembly is surrounded by a secondary winding that is precisely located in a burner assembly housing. Conductive members are encased within the housing and, in conjunction with traces provided on a printed circuit board enclosing the housing cavity, define first and second primary windings about the core secondary winding. This arrangement reduces the number of turns in the secondary winding and allows the use of larger cross-sectional wire which increases the current carrying capability thereof, making the transformer suitable for D1-D5 automotive headlamp applications.
摘要:
An integrated lamp/lamp electronics unit includes a lamp having a first end with first end electrical terminals, and a second end with second end electrical terminals. An end cap having an interior section is placed into electrical connection with the first end electrical terminals at the first end of the lamp. Lamp electronics are configured to control operation of the lamp and are connected only to the second end electrical terminals. The lamp electronics are carried on a circuit board having a configuration substantially matching the second end of the lamp portion. The circuit board is placed within the interior of a lamp electronics end cap, and the end cap is attached in a permanent relationship to the second end of the lamp.
摘要:
A ballast circuit for a gas discharge lamp includes a resonant load circuit incorporating a gas discharge lamp and including first and second resonant impedances whose values determine the operating frequency of the resonant load circuit. Further included is a d.c.-to-a.c. converter circuit coupled to the resonant load circuit so as to induce an a.c. current in the resonant load circuit. The converter includes first and second switches serially connected between a bus conductor at a d.c. voltage and ground, and has a common node through which the a.c. load current flows. A feedback circuit provides a feedback signal indicating the level of current in the resonant load circuit. A high voltage IC drives the first and second switches at a frequency determined by a timing signal which predominantly comprises the feedback signal during lamp ignition, whereby during lamp ignition the feedback signal causes the high voltage IC to drive the first and second switches towards a switching frequency which promotes resonant operation of the resonant load circuit.
摘要:
The present invention is directed to a control circuit for providing a substantially constant current to a high-pressure sodium lamp. The control circuit preferably comprises a circuit for providing a rectified voltage signal, and a ballast having first and second contacts to operatively connect the lamp therebetween. The ballast generates and controls a peak current through the lamp based on the value of a controlled voltage. The control circuit further comprises a current sensor to sense the amount of current through the lamp, and a buck-boost voltage control circuit to control the value of the controlled voltage in order to provide a substantially constant peak current through the lamp based on the amount of current sensed by the current sensor. By controlling the amount of voltage seen by the lamp, the buck-boost voltage control circuit controls the amount of current through the lamp, thereby providing constant color temperature regardless of the fluctuations in lamp impedance.
摘要:
Disclosed are a lamp igniter module and method of assembling a lamp igniter module. The lamp igniter module comprises a transformer carrier, a slide-in electrical connector, a pc board, and a housing. Assembly of the lamp igniter module is accomplished by initially inserting a transformer carrier assembly within the housing and subsequently installing a slide-in electrical connector which may or may not be attached to the pc board.
摘要:
A ballast circuit for a gas discharge lamp with a tapless feedback circuit is disclosed. The ballast circuit comprises 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 determines the conduction state of the associated switch. The respective reference nodes of the switches are connected together at a common node through which the a.c. current flows, and the respective control nodes of the switches are connected together. A gate drive arrangement regeneratively controls the first and second switches. It comprises a coupling circuit including an inductor for coupling to the control nodes a feedback signal representing current in the load circuit. It further comprises a tapless feedback circuit for providing the feedback signal. The feedback circuit comprises a capacitor coupled at one end to the common node in such manner as to conduct load current, and coupled at another end to the inductor.
摘要:
A ballast circuit for a gas discharge lamp comprises a resonant load circuit including the lamp. A d.c.-to-a.c. converter circuit induces an a.c. current in the resonant load circuit. The converter circuit comprises first and second switches serially connected between a bus conductor at a d.c. voltage and a reference conductor, and being connected together at a common node through which the a.c. load current flows. The first and second switches each comprise a reference node and a control node, the voltage between such nodes determining the conduction state of the associated switch. The respective reference nodes of the first and second switches are interconnected at the common node. The respective control nodes of the first and second switches are interconnected. An inductance is connected between the control nodes and the common node. A starting pulse-supplying capacitance is connected in series with the inductance, between the control nodes and the common node. A network is connected to the control nodes for supplying the starting pulse-supplying capacitance with charge so as to create a starting pulse during lamp starting, and for setting the voltage of the control nodes sufficiently close to that of the common node during steady state lamp operation so as to prevent the capacitance from supplying a starting pulse during the steady state lamp operation. A polarity-determining impedance is connected between the common node and one of the bus conductor and the reference conductor, to set the initial polarity of pulse to be generated by the starting pulse-supplying capacitor.
摘要:
A ballast circuit for a gas discharge lamp, of the type having a pair of resistively heated cathodes that are resistively heated both during a cathode pre-heat period prior to lamp turn-on, and during steady state lamp operation, is disclosed. The ballast circuit includes circuitry for providing, on a bus conductor, a d.c. bus voltage with respect to a ground, and a converter, responsive to the d.c. bus voltage, for supplying bidirectional current to a resonant load circuit. The resonant load circuit includes the gas discharge lamp, a resonant capacitor coupled between the lamp cathodes such that its voltage varies with lamp voltage, and a resonant inductor serially coupled to the resonant capacitor and cooperating therewith to set a magnitude, and resonant frequency, of the bidirectional lamp current. Circuitry is provided for powering the resistively heated lamp cathodes, to thereby heat the cathodes. Further included is a circuit for maintaining the lamp voltage during a cathode pre-heat period below a predetermined level so as to prevent lamp turn-on during such period; such circuit includes circuitry for holding a first cathode of the lamp at a substantially constant voltage, and circuitry for clamping a second cathode of the lamp below the predetermined level. Such clamping circuitry includes a positive temperature coefficient (PTC) impedance device coupled to a second cathode of the lamp, and serially connected by a positively poled clamping diode to the bus conductor, and serially connected by a negatively poled clamping diode to the ground.
摘要:
A power supply circuit for powering a load with bi-directional current comprises means for supplying d.c. power from an a.c. voltage, a series half-bridge converter, and a boost converter. The series half-bridge converter alternately impresses a d.c. bus voltage from a bus conductor across a load circuit first with one polarity and then with the opposite polarity. The series half-bridge converter includes a first switch interposed between the bus conductor and a bridge-switch end of the load circuit; a second switch interposed between ground and the bridge-switch end of the load circuit; and a switching control circuit for alternately switching on the first and second switches. The boost converter comprises a boost capacitor connected between the bus conductor and ground and whose level of charge determines the bus voltage on the bus conductor; a boost inductor for storing energy from the means for supplying d.c. power, the boost inductor being connected by a one-way valve to the boost capacitor for discharging its energy into the boost capacitor; and means for periodically connecting a load end of the boost inductor through a low impedance path to ground, such path including a boost switch. A condensed power supply circuit results from making the second switch of the series half-bridge converter additionally serve as the boost switch. An alternative circuit simplification results from making constant the ratio of on time to switching repetition period of the boost switch.