Matsushita Electric Works, Ltd.

Panasonic Corporation

Matsushita Electric Works R&d Laboratory, Inc.

Panasonic Electric Works Co., Ltd.

Universal Lighting Technologies, Inc.

Yiyoung Sun

Kenichi Fukuda

Takeshi Goriki

Nanu Brates

Bhavinkumar Shah

Takeshi Kamoi

Naoki Komatsu

Tsutomu Shiomi

Hiroyasu Eriguchi

Hiroichi Shinbori

An apparatus for operating a gas discharge lamp. The apparatus includes an electronic ballast and a controller. The electronic ballast includes a half bridge configuration, a full bridge configuration, a first network, and a second network. The electronic ballast is controlled by a controller that causes the half bridge configuration to ignite an arc between electrodes of the gas discharge lamp in an igniter function that uses the first network, to switch the electronic ballast from the half bridge configuration to the full bridge configuration after the arc is ignited so that a buck inverter function using the second network sustains the arc between the electrodes of the gas discharge lamp, and to provide a transient operation function to the buck inverter function to produce a spike voltage that is used to re-ignite the arc between the electrodes of the gas discharge lamp when the arc extinguishes.

Circuit arrangement for operating a discharge lamp

A lamp ballast is provided for igniting and operating an HID lamp. A buck inverter circuit includes a pair of high-frequency and a pair of low-frequency switches. A capacitor and an inductor are series-connected between a first node between the low frequency switches and a second node between the high frequency switches. A lamp igniting circuit is coupled between the first node and a first lamp output terminal, and a second lamp output terminal is coupled to a third node between the capacitor and the inductor. A control circuit turns on and off the switches to regulate low frequency square wave voltage generated across the lamp output terminals to be less than an input DC voltage from the positive rail, wherein the buck inverter operates in either of a critical discontinuous mode or a discontinuous mode during an open circuit operation, and in a critical discontinuous mode during other operations.

System and method for regulating an open circuit voltage of an HID lamp ballast

An apparatus and method for detecting an end of life (EOL) condition of a lamp that exhibits a re-ignition behavior. A voltage is applied to the lamp to cause the lamp to start emitting light, and a lamp re-ignition voltage to normal lamp voltage difference after a mask-off period expires is monitored. The lamp is determined to have reached the EOL condition when a predetermined percentage of high difference half cycles occur during a set number of lamp voltage half cycles that are measured during a measurement window. The method continuously monitors the lamp re-ignition voltage to normal lamp voltage difference and records whenever the lamp re-ignition voltage to normal lamp voltage difference is higher than the re-ignition difference threshold level at any lamp voltage half cycle. An EOL lamp is detected when a predetermined number of high difference half cycles occurs in a set total number of lamp voltage half cycles measured in a rolling measurement window.

End-of-life protection circuit and method for high intensity discharge lamp ballast

An apparatus and method thereof for igniting and operating a high intensity discharge (HID) lamp during an in service life, and powering down the lamp when an end-of-life (EOL) lamp condition is detected. The apparatus and method defines a series of thresholds of lamp voltage asymmetry, or rectification thresholds, and monitors the lamp rectification from ignition through normal operation. The detection scheme is masked off for a predetermined period of time when the lamp is initially started. Thereafter, the rectification threshold of the lamp voltage asymmetry is gradually reduced over time, until a defined minimum rectification threshold level is reached and maintained. The method continuously monitors the lamp voltage and records whenever the lamp voltage asymmetry is higher than the rectification threshold level at any lamp voltage cycle. An EOL lamp condition is determined to exist when a certain number of high asymmetrical cycles occurs in selected total number of lamp voltage cycles during a rolling measurement window.

An electronic ballast includes a microprocessor which is programmed to read a voltage value corresponding to an output of the electronic ballast, output a signal which controls an amount of power outputted by the electronic ballast in accordance with the voltage value, read an external voltage value, and select one of a trimming mode and a normal mode as an operating mode based on the external voltage value. The microprocessor is also programmed, when operating in the trimming mode, to set an internal reference value, compare the voltage value corresponding to the output of the electronic ballast with the internal reference value, trim an amount of power outputted by the electronic ballast to a resistor corresponding to an impedance of a High Intensity Discharge lamp by adjusting the signal based upon the comparison, and store a result of the signal adjustment.

Apparatus and method for automatically trimming an output parameter of an electronic ballast

A method and apparatus for protecting a discharge lamp lighting device from damage due to mis-wiring of a source of electrical power to the discharge lamp lighting device. The protection apparatus includes a detector, a comparer and an inhibitor. The detector samples at least one monitor point associated with the discharge lamp lighting device to obtain at least one detection voltage. The comparer compares the at least one detection voltage with a reference voltage. The inhibitor inhibits an operation of the discharge lamp lighting device when the comparer determines that a mis-wiring of the source of electrical power to the discharge lamp lighting device exists.

Discharge lamp lighting device, lighting system and method

Circuit and method for driving a gas discharge lamp having a bridge converter. The bridge converter includes a plurality of switches. A controller turns on and off the plurality of switches. The circuit further includes a zero current sensor circuit. The controller senses at least one voltage differential to control a length of time that at least one of the at least four switches is on. The controller controls when at least one of the plurality of switches is turned on in accordance with an output of the zero cross sensor.

Method and circuit for driving a gas discharge lamp

A circuit arrangement and control thereof for igniting a high intensity discharge lamp, for reducing current stresses imposed on semiconductor devices during a polarity transition of a lamp voltage or lamp current, and for maintaining a parasitic current within an envelope of a square wave lamp current. A high frequency ignition voltage is only applied to the lamp during a starting operation. After the lamp breaks down in the starting operation, an imbalanced high frequency current flows through the lamp to assist a glow-to-arc transition. The high discharge current of the buck filter capacitor that is generally applied to the semiconductor devices during the polarity transition of the lamp voltage or lamp current, due to lamp extinguishing, is reduced. The lamp current is maintained as a low frequency square wave. Any spikes that may occur at the polarity transition of the lamp voltage or lamp current are superimposed on the lamp current within the envelope of the low frequency square wave lamp current.

Apparatus and method for driving a high intensity discharge lamp

A circuit arrangement and control thereof for igniting a high intensity discharge (HID) lamp, for reducing the variation of the resonant ignition voltage under the parasitic capacitive loading condition, and for increased circuit stability. The high frequency ignition voltage is only applied to the lamp during an ignition phase. The variation of the magnitude of the resonant ignition voltage with respect to the parasitic capacitance at the lamp leads is minimized by inserting a damping resistor in series with the ignition resonant capacitor. In a normal operation after ignition, the charge and/or discharge current of the ignition resonant capacitor is bypassed through a bypass device instead of flowing through a current sense resistor, so that only a chopper current flows through a sensor by paralleling a relatively high impedance resistor with the sensor.

Circuit for driving an HID lamp

A discharge lamp lighting device which comprises a D.C. power supply, a load resonance circuit including an inductor, a capacitor and a discharge lamp; a polarity inverting circuit including at least a series circuit of first and second switching elements connected in parallel to the D.C. power supply for converting a D.C. power received from the D.C. power supply into an A.C. power to supply it to the load resonance circuit; and a control circuit for turning ON and OFF the switching elements alternately at a high frequency to alternately generate a first period during which an ON duration of the second switching element is longer than that of the first switching element and a second period during which the ON duration of the second switching element is shorter than that of the first switching element, to thereby apply a rectangular-shaped low frequency voltage to the discharge lamp. The control circuit superimposes a D.C. component in an output of the polarity inverting circuit upon a resonance pulse signal from the load resonance circuit to continuously change a switching frequency of the switching elements for the predetermined time from the start time point of one of the first and second periods, and supplies to the discharge lamp a first energy necessary for starting and lighting the discharge lamp with a high pulse voltage obtained through LC resonance and also for smoothly shifting the lamp to an arc discharge state.

Discharge lamp lighting device of high startability with high pulse voltage

A circuit arrangement and method thereof for operating high intensity discharge (HID) lamps with a lower frequency rectangular current waveform, in which the frequency of the higher frequency ripple superimposed on the lower frequency rectangular current is modulated by a pseudo-random noise signal. The pseudo-random noise may be generated by a feedback shift register. The feedback shift register may incorporate run length interrupt logic to address PWM frequency stagnation by reducing the longest run length or lengths of the feedback shift register. The feedback shift register may also or alternatively include an RC low pass analog filter to address PWM frequency stagnation. The center frequency and frequency band of the pseudo-randomly generated noise may be adjustable.

Method and driving circuit for HID lamp electronic ballast

A circuit arrangement and control thereof for igniting a high intensity discharge (HID) lamp, for reducing the high frequency ripple superimposed on the low frequency rectangular waveform lamp current after ignition, and for increased circuit efficiency. The high frequency ignition voltage is only applied to the lamp during ignition phase and is mainly generated by the second stage of the low pass (LP) filter. The first stage of the LP filter whose resonant frequency is below the second stage further attenuates the high frequency ripple current through the lamp in normal operation. The resulting lamp current is a low frequency rectangular wave with less than 10% high frequency ripple. Acoustic resonance is avoided. The inductor in the first stage of LP filter is operated in discontinuous current mode. Doing so, the active switches are in zero current switching (ZCS) to maximize the circuit efficiency.

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Beverly, MA, United States of America

Yiyoung Sun