A lamp assembly configured to inductively receive power from a primary coil. The lamp assembly includes a lamp circuit including a secondary and a lamp connected in series. In a first aspect, the lamp circuit includes a capacitor connected in series with the lamp and the secondary to tune the circuit to resonance. The capacitor is preferably selected to have a reactance that is substantially equal to or slightly less than the reactance of the secondary and the impedance of the lamp. In a second aspect, the lamp assembly includes a sealed transparent sleeve that entirely encloses the lamp circuit so that the transparent sleeve is fully closed and unpenetrated. The transparent sleeve is preferably the lamp sleeve itself, with the secondary, capacitor and any desired starter mechanism disposed within its interior.

Inductively powered lamp assembly

When a discharge lamp is started, high voltage pulses which superpose the voltage due to LC resonance of a resonance circuit are supplied to the discharge lamp, and breakdown occurs in the discharge lamp. The pulse energy needed for the high voltage pulses is small and the output power of the resonance circuit can be decreased. After the breakdown, the energy needed for the transfer from glow discharge to arc discharge is supplied by the resonance, and the high voltage pulses used to supply the starting energy are allowed to be stopped. Thus, the starting and restriking of a discharge lamp is sure, and the starting circuit for a discharge lamp can be made more compact.

Discharge lamp starting circuit

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.

Electronic ballast with two-step boost converter and method

An electronic energization circuit is provided to illuminate a gas discharge lamp that includes a transformer with a substantially rectangular hysteresis loop. A secondary winding on the transformer is connected to energize the lamp and at least one primary winding is provided on the transformer. Input voltage terminals may be DC terminals to supply an input voltage to the circuit. At least one semiconductor, such as a transistor, is connected to the input terminals and to the at least one primary winding, and a control means is provided for the semiconductor for unequal on and off conduction periods of the semiconductor. These unequal periods provide the conditions which eliminate the striations (bubbles) or dark spots in the gas plasma of the lamp, usually associated with high frequency energization. When two semiconductors are used in a circuit, they conduct alternately in a type of square wave oscillator circuit and the duty cycle of the two transistors is different so that the striations in the illumination of the lamp are eliminated. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

Gas discharge lamp energization circuit

A starter circuit for a fluorescent tube lamp is connected between the cathode heaters of the tube to provide an initial heating current and then changes to a high impedance to ignite the tube. The circuit is fed by raw rectified a.c. and has a main thyristor requiring a high holding current to maintain the initial conduction. The current through the main thyristor sets up a voltage across a series diode which triggers a second thyristor to reduce the gate voltage of the main thyristor. The main thyristor ceases conduction when the current falls below the holding value and the inductive ballast impedance then produces a high energy striking pulse for the tube. The pulse voltage is limited to increase its duration. One embodiment generates a single pulse only each time the circuit is switched on and another embodiment produces pulses for a period of time before becoming quiescent. The main thyristor and the voltage limiting means are embodied in a monolithic semiconductor structure.

Starter circuit for a fluorescent tube lamp

An energization arrangement for a discharge lamp includes a DC/AC converter to which a discharge lamp (81) is connected. The lamp is shunted by a relay contact (90) to obtain an electric circuit through which two electrodes (83, 84) of the lamp can be preheated. It is advantageous to insure that the relay contact is closed before a voltage occurs between the electrodes of the lamp. This prevents the lamp from exhibiting a transient flash at too cold electrodes. A timing circuit (40-47) ensures that the relay contact remains closed for about 1 second, after which the lamp ignites with warm electrodes. No electrical losses occur in the relay winding (30) during operation of the lamp.

High efficiency converter for discharge lamps

A starter circuit for a discharge lamp includes an inductor in series with the lamp across the AC input terminals and an SCR in shunt with the lamp and in series with the lamp electrodes. A resistor and capacitor are connected in series across the lamp. The impedance of the capacitor is 40 times to 150 times the lampoperating impedance and is approximately 95 percent of the impedance of the series RC circuit. A control circuit ignites the SCR between 30* and 135* after the zero crossing of the AC supply voltage.

A starter circuit for a discharge lamp having preheated electrodes

The invention relates to a circuit arrangement for operating a high-pressure sodium lamp provided with two lamp connection points. The circuit arrangement comprises a controlled main switching element, a control electrode of which is connected to a control circuit. The circuit arrangement is provided with a measuring impedance in series with a lamp connection point and with a measuring impedance parallel to the lamp connection points. The measuring impedances are connected to the control circuit. A combination of a resistor and a capacitor is further connected to the control circuit and this combination is connected in series with one lamp connection point.

Circuit arrangement for operating a high-pressure sodium discharge lamp

The invention relates to a circuit arrangement suitable for operating a high-pressure discharge lamp (80) in conjunction with a controlled current limiter (6) by means of a control signal which is at least composed of a sum of a lamp-voltage-dependent part and a lamp-­current-dependent part. According to the invention, the absolute value of the lamp-current-dependent part is chosen to be smaller than the absolute value of the lamp-voltage-dependent part. With this circuit arrangement, a rapid control is possible, which keeps the lamp voltage substantially constant.

Hilbert Palmers

Papers

High efficiency converter for discharge lamps

A starter circuit for a discharge lamp having preheated electrodes

Circuit arrangement for operating a high-pressure sodium discharge lamp

Circuit arrangement suitable for operating a high-pressure discharge lamp

Vorrichtung zum Speisen bzw. Zuenden einer Gas- und/oder Dampfentladungsroehre mittels einer Hochfrequenzspannung