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US 6,388,397 B1Granted
Discharge lamp lighting device
AssigneeMatsushita Electric Works, Ltd.
InventorYutaka Iwahori
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AssigneeMatsushita Electric Works, Ltd.
InventorYutaka Iwahori
Estimating the term…
A discharge lamp lighting device includes first power converting circuit converting an input source voltage into another DC voltage, second power converting circuit constituted by a buck converter, and a discharge lamp as a load driven by an output of the second power converting circuit. The device being so controlled that a switching element in the second power converting circuit will be turned ON when the voltage across the switching element is the minimality. Wherein a unit is provided for regulating an output voltage of the first power converting circuit in a direction of reducing the voltage across the element immediately before turning ON of the second power converting circuit, and a highly efficient operation can be always realized irrespective of conditions of the load.
A discharge lamp lighting device comprising first power converting circuit for converting an input source power voltage into another DC voltage, second power converting circuit having a buck converter which includes at least a switching element, a control means for controlling an output voltage of the first power converting circuit toward a reduction of a voltage across the switching element immediately before turning ON of the element in the second power converting circuit, and a discharge lamp driven by an output voltage of the second power converting circuit.
A discharge lamp lighting device comprising first power converting circuit for converting an input source power voltage into another DC voltage, second power converting circuit having a buck converter which includes at least a switching element, a control means for controlling an output voltage of the first power converting circuit toward a reduction of a voltage across the switching element immediately before turning ON of the element in the second power converting circuit, a discharge lamp driven by an output voltage of the second power converting circuit, and a lamp voltage detecting means connected across the discharge lamp to detect a lamp voltage and to provide the lamp voltage detected to the control means as a reference voltage for the first power converting circuit, wherein the control means is provided for setting the output voltage of the first power converting circuit to be between 1.5 time and 2.5 times as high as the lamp voltage detected of the discharge lamp being lighted.
A discharge lamp lighting device comprising first power converting circuit for converting an input source power voltage into another DC voltage, second power converting circuit having a buck converter which includes at least a switching element, a control means for controlling an output voltage of the first power converting circuit toward a reduction of a voltage across the switching element immediately before turning ON of the element in the second power converting circuit, and a discharge lamp driven by an output voltage of the second power converting circuit, wherein the first power converting circuit is formed by connecting positive and negative polarity terminals of a DC power source through first and second switching elements to both ends of an inductor, connecting first diode in parallel to a series circuit of the first switching element and the DC power source in opposite direction to the DC power source, and connecting a bulk capacitor through second diode across the second switching element, whereby the first power converting circuit being operated as a boost converter with the first switching element kept in ON state and with the second switching element turned ON and OFF, and as a buck boost converter with both switching elements turned ON and OFF as synchronized.
A discharge lamp lighting device comprising a rectifier for rectifying an input voltage from an AC power source, a boost converter for boosting an output voltage of the rectifier, a buck converter for dropping an output voltage of the boost converter, control means for controlling the output voltage of the boost converter toward a reduction of a voltage across a switching element in the buck converter immediately before turning ON of the switching element so that the switching element turns ON at a timing when the voltage across the switching element becomes the minimality, and a discharge lamp driven by an output voltage of the buck converter.
A discharge lamp lighting device comprising first power converting circuit for converting an input source power voltage into another DC voltage, second power converting circuit having a buck converter which includes at least a switching element, a control means for controlling an output voltage of the first power converting circuit toward a reduction of a voltage across the switching element immediately before turning ON of the element in the second power converting circuit, and a discharge lamp driven by an output voltage of the second power converting circuit;
A discharge lamp lighting device comprising first power converting circuit for converting an input source power voltage, second power converting circuit having a buck converter which includes at least a switching element, a control means for controlling an output voltag of the first power converting circuit toward a reduction of a voltage across the switching element immediately before turning ON of the element in the second power converting circuit, and a discharge lamp driven by an output voltage of the second power converting circuit, wherein the second power converting circuit further includes an inductor and is controlled for turning ON the switching element after a time defined by
A discharge lamp lighting device comprising a boost converter receiving an input pulsating voltage from a DC power source and including at least a switching element, an inductor and a rectifying element;
A discharge lamp lighting device comprising a boost converter receiving an input pulsating voltage form a DC power source and including at least a switching element, an inductor and a rectifying element;
Dependencies are inferred from the claim text.
No related US applications are recorded in the indexed filing history.
Using static converters: with semiconductor devices
With semiconductor devices: by means of a single-switch converter or a parallel push-pull converter in the final stage
Electric lamp and discharge devices: systems: starting and operating circuit for fluorescent lamp
Electric heating
Term ended 20 Apr 2020 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
This invention relates to a discharge lamp lighting device and, in particular, to a device for lighting a discharge lamp and including an electronic ballast having a function of improving input current distortion.
In an aspect of the discharge lamp lighting device of the kind referred to, the device is provided with a DC power source of which a voltage fluctuates, such as a pulsating flow power source of a commercial AC source power rectified by a full-wave rectifier, and includes a boost converter as a first power converting circuit, a buck converter as a second power converting circuit, and a discharge lamp as a load. In the first power converting circuit, more specifically, an inductor is connected at one end to a positive polarity terminal of the DC power source, and at the other end through a switching element to a negative polarity terminal of the DC power source, and a diode is connected at its anode to a node of the inductor and the switching element, while the cathode of this diode is connected to a positive polarity terminal of a bulk capacitor which is connected at a negative polarity terminal to a positive polarity terminal of the DC power source. The switching element can be ON/OFF controlled by a control circuit. When this switching element is ON, a current flows from the DC power source through the inductor and switching element, and an energy is accumulated in the inductor. When the switching element is OFF, on the other hand, an electromotive force due to the energy accumulated in the inductor is superposed on a voltage of the DC power source and is charged through the diode in the bulk capacitor. On this account, the bulk capacitor is charged up to above a peak voltage of the DC power source. A boost converter as a first power converting circuit is constituted with this arrangement.
The DC voltage of the bulk capacitor is dropped by the buck converter as the second power converting circuit, and is applied to the load discharge lamp. The buck converter represented by an equivalent circuit is connected at one end of the switching element to the ground level to be able to easily drive the switching element. The switching element is connected at one end to the negative polarity terminal of the bulk capacitor and at the other end through the anode and cathode of the diode to the positive polarity terminal of the bulk capacitor An end of the inductor is connected to the anode of the diode. The other end of the inductor is connected through a parallel circuit of a capacitor and the load discharge lamp to the positive polarity terminal of the bulk capacitor.
FIG. 1 is a basic block circuit diagram in an embodiment of the discharge lamp lighting device according to the present invention;
FIG. 2 is a circuit diagram in another embodiment of the device according to the present invention;
FIGS. 3 and 4 are explanatory diagrams for the operation of the circuit in FIG. 2;
A basic circuit diagram in an embodiment of the discharge lamp lighting device according to the present invention is shown in FIG. 1. The discharge lamp lighting device according to the present invention is provided with such first power converting circuit CNV1 as a boost converter. And this first power converting circuit CNV1 is connected to an input power source (not shown) which is likely to cause the load fluctuation to occur. The second power converting circuit CNV2 as the buck converter is connected to this first power converting circuit CNV1. This second power converting circuit CNV2 is connected to such load L of a large impedance fluctuation as a high intensity discharge lamp. An output voltage control circuit CNT capable of regulating the output voltage of this converting circuit is connected to the first power converting circuit CNV1.
Accordingly, it is enabled to realize constantly the highly efficient operation, irrespective of conditions of the load, by regulating, for example, the output voltage of the first power converting circuit toward a reduction of the voltage across the switching element included in the second power converting circuit immediately before turning ON of this switching element.
In FIG. 2, there is shown a somewhat practical circuit diagram in another embodiment of the discharge lamp lighting device according to the present invention. An inductor Ld is connected at one end to a positive polarity terminal of such DC power source E the voltage of which fluctuates as a pulsating power source obtained by rectifying, for example, a commercial AC source power with a full wave rectifier, and at the other end through a switching element Qd to a negative polarity terminal of the DC power source E. A diode Dd is connected at its anode to a node of the inductor Ld and the switching element Qd, and at the cathode to a positive polarity terminal of a bulk capacitor Ce. And the a negative polarity terminal of the capacitor Ce is connected to the positive polarity terminal of the DC power source E. The switching element Qd is ON/OFF controlled by a control circuit 3. When the switching element Qd is ON, a current flows from the DC power source E through the inductor Ld and switching element Qd to have an energy accumulated in the inductor Ld. As the switching element Qd turns OFF, the bulk capacitor Ce is charged through the diode Dd with an electromotive force due to the accumulated energy in the inductor Ld. With this circuit, a buck boost converter 1 forming the first power converting circuit is constituted.