JP2005004980A - Discharge lamp lighting device - Google Patents

Abstract

Disclosed is a discharge lamp lighting device that facilitates starting of a discharge lamp and can be reduced in size and weight.
A discharge lamp, a chopper circuit for converting a power supply input voltage into a voltage and current required for operation, a pulse voltage generation circuit for supplying a constant voltage and current, and a high voltage to the discharge lamp In a discharge lamp lighting device comprising a transformer 3 for supplying a direct current component, a DC component generating secondary winding S1 of the transformer 3 and a diode connected in series to the input side of the DC component generating secondary winding S1 A DC generation circuit for generating a DC component having a voltage higher than the power supply input voltage, and comprising a capacitor C3 connected in parallel with D2, a diode D2 and a DC component generating secondary winding S1, and its DC generation A pulse voltage superimposing circuit that superimposes a pulse voltage on a DC component generated by the circuit is provided.
[Selection] Figure 1

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a discharge lamp lighting device, and more particularly to a discharge lamp lighting device capable of miniaturizing and reducing the weight of a high-voltage generating transformer to be used by suppressing a voltage peak value at the time of starting the discharge lamp to a low level. .
[0002]
[Prior art]
FIG. 5 is a circuit diagram of a conventional discharge lamp lighting device. In the figure, 1 is a control circuit section, 2 is a pulse voltage generating circuit, 3 is a high voltage pulse voltage generating transformer (T1), 4 is a chopper circuit, and 5 is a discharge lamp.
[0003]
The control circuit unit 1 has a power, voltage, current control function, lighting detection, protection circuit function, high voltage generation, timing function, etc., and receives a voltage detection signal and a current detection signal from the chopper circuit 4 and a pulse voltage A high voltage generation signal is output to the generation circuit 2 and a switching signal is output to the chopper circuit 4.
[0004]
The pulse voltage generation circuit 2 includes a resistor R2, a capacitor C2, and a switch element (transistor, thyristor, etc.) Q6.
[0005]
The high voltage pulse voltage generating transformer (T1) 3 generates a high voltage when the discharge lamp 5 is started. The pulse waveform generated by the pulse voltage generation circuit 2 is applied to the primary winding P1 of the transformer (T1) 3, and a high voltage pulse obtained from the secondary winding P2 is supplied to the discharge lamp 5.
[0006]
The chopper circuit 4 includes a switching element (transistor or the like) Q1, a coil L1, a diode D1, a current detection resistor Rs, a capacitor C1, and the like, and converts a power supply input voltage (VIN) into a voltage and a current necessary for operation. It has a function.
[0007]
It has been found that due to the short arcing of the discharge lamp in recent years, the interval between the discharge electrodes is shortened, and discharge is started by applying a low DC component. In recent discharge lamps, arc lengths of 1 mm to 1.5 mm have become mainstream, and it has also been found that the discharge start voltage is about 1 kV to 2 kV.
[0008]
Since the discharge lamp contains a rare gas such as argon in order to enhance luminance and color rendering, glow discharge is likely to occur at a lower voltage. The discharge lamp contains a substance such as xenon or mercury as a main component. When the discharge lamp reaches a sufficient temperature and the brightness is stabilized, this substance evaporates inside the lamp and becomes a high pressure, which increases the breakdown voltage immediately after the lamp is turned off.
[0009]
In order to light the discharge lamp continuously, it is necessary to set the pulse voltage at the start-up to be equal to or higher than the dielectric breakdown voltage and to apply energy for continuing the discharge. In order to increase the energy for making this discharge continuous, it is effective to widen the pulse width at start-up.
[0010]
In addition, when the discharge lamp is lit continuously, the amount of energy required for electron emission changes depending on the temperature of the electrode, but in experiments, it was found that the higher the electrode temperature, the easier the electron emission and the easier the emission. did.
[0011]
The discharge phenomenon of the discharge lamp is closely related to the temperature of the lamp and the electrode. When the rare gas temperature inside the lamp is high, even when the temperature of the electrode is high and electrons are easily emitted, continuous emission of electrons, In order to maintain the discharge, a high voltage of several kV or more is required.
[0012]
As a conventional discharge lamp lighting device, for example, the following Patent Document 1 can be cited.
[0013]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-3996
[Problems to be solved by the invention]
By the way, in the conventional discharge lamp lighting device, the turn ratio of the primary winding P1 and the secondary winding P2 of the high voltage pulse voltage generating transformer (T1) 3 is set to a high voltage value necessary for relighting when the lamp is hot. There is a need.
[0015]
However, if a high voltage value is used, the same current as the lamp current flows through the secondary winding P2 of the transformer (T1) 3. Therefore, it is necessary to increase the wire diameter of the winding. 3) It was difficult to reduce the size and the weight of the discharge lamp lighting device, and consequently to reduce the size and the weight of the discharge lamp lighting device.
[0016]
An object of the present invention is to provide a discharge lamp lighting device that eliminates the drawbacks of the prior art and can be reduced in size and weight.
[0017]
[Means for Solving the Problems]
In order to achieve the above object, the first means of the present invention includes a discharge lamp,
A chopper circuit that converts the power input voltage into the voltage and current required for operation;
A pulse voltage generation circuit for supplying a constant voltage and current;
In a discharge lamp lighting device comprising a transformer for supplying a high voltage to the discharge lamp,
The DC component generating secondary winding of the transformer, a diode connected in series to the input side of the DC component generating secondary winding, and the diode and the DC component generating secondary winding in parallel A direct current generating circuit for generating a direct current component having a voltage higher than the power input voltage;
A pulse voltage superimposing circuit that superimposes a pulse voltage on the DC component generated by the DC generating circuit is provided.
[0018]
According to a second means of the present invention, in the first means, the pulse voltage superposition circuit has a secondary winding for generating a pulse voltage provided on the secondary winding side of the transformer, and the pulse voltage generation The secondary winding for use is connected in series to the output side of the secondary winding for generating DC component.
[0019]
According to a third means of the present invention, in the first means, a bypass diode is connected in parallel to the diode connected in series to the input side of the DC component generating secondary winding, The current path is bypassed by the bypass diode.
[0020]
According to a fourth means of the present invention, in the third means, a relay is connected in parallel to the bypass diode, and the relay is short-circuited by the relay.
[0021]
According to a fifth means of the present invention, in the first means, a MOSFET is connected in parallel to a diode connected in series to the input side of the DC component generating secondary winding, and the MOSFET of the MOSFET is continuously operated. A voltage is applied to the gate to turn on between the drain and the source.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram of a discharge lamp lighting device according to a first embodiment of the present invention.
[0023]
In the figure, 1 is a control circuit section, 2 is a pulse voltage generating circuit, 3 is a high voltage pulse voltage generating transformer (T1), 4 is a chopper circuit, 5 is a discharge lamp, and 6 is a DC generating circuit.
[0024]
The control circuit unit 1 has a power, voltage, current control function, lighting detection, protection circuit function, high voltage generation, timing function, etc., and receives a voltage detection signal and a current detection signal from the chopper circuit 4 and a pulse voltage A high voltage generation signal is output to the generation circuit 2 and a switching signal is output to the chopper circuit 4.
[0025]
The pulse voltage generation circuit 2 includes a resistor R2, a capacitor C2, and a switch element (transistor, thyristor, etc.) Q6.
[0026]
The high voltage pulse voltage generating transformer (T1) 3 has a pulse voltage generating secondary winding S2 connected in series to the output side of the DC component generating secondary winding S1. The pulse waveform generated by the pulse voltage generation circuit 2 is applied to the primary winding P1 of the transformer (T1) 3, and the high-pressure pulse obtained from the secondary windings S1 and S2 is supplied to the discharge lamp 5.
[0027]
The chopper circuit 4 includes a switching element (transistor or the like) Q1, a coil L1, a diode D1, a current detection resistor Rs, a capacitor C1, and the like, and converts a power supply input voltage (VIN) into a voltage and a current necessary for operation. It has a function.
[0028]
The DC generation circuit 6 includes a secondary winding S1 of the transformer (T1) 3, a diode D2 connected in series to the input side of the secondary winding S1, and the diode D2 and the secondary winding S1. And a capacitor C3 connected in parallel to generate a DC component having a voltage higher than the power supply input voltage (VIN). That is, by switching the primary winding P1 of the transformer (T1) 3 with the switch element Q6, the secondary winding S1 is set to generate a low voltage of 1 kV to 2 kV in the present embodiment.
[0029]
Further, a pulse voltage Vps is generated by the secondary winding S1 and the secondary winding S2 connected in series. The direct current component (1 kV to 2 kV) generated by the secondary winding S1 is necessary for relighting. The pulse voltage Vps to be superimposed is superimposed. In the present embodiment, the pulse voltage Vps is set to an arbitrary value of several hundred V to several kV.
[0030]
FIG. 2 is a diagram showing a lamp lighting operation waveform. As shown in the figure, the pulse voltage Vps (several hundred V to several kV) generated by the secondary winding S2 is superimposed on the DC component (1 kV to 2 kV) generated by the secondary winding S1 during re-lighting.
[0031]
Further, a bypass diode D3 is connected in parallel to the diode D2 connected in series to the input side of the secondary winding S1, and the current path during lighting is bypassed by the diode D3. By this bypass, the diode D2 can be reduced in size and the transformer (T1) 3 can be reduced in size and weight by thinning the secondary winding S1.
[0032]
FIG. 3 is a circuit diagram of a discharge lamp lighting device according to the second embodiment of the present invention. This embodiment differs from the first embodiment shown in FIG. 1 in that a relay RL1 is connected in parallel to the diode D3 and is short-circuited by the relay RL1, and the chopper circuit 4 and pulse This is the point that an AC exchange circuit that generates AC voltage and current is provided between the voltage generation circuit 2 and includes Q2 to Q5. The Q2 to Q5 are composed of transistors, MOSFETs and the like. Control signals for AC exchange are output from the control circuit unit 1 to Q2 to Q5.
[0033]
FIG. 4 is a circuit diagram of a discharge lamp lighting device according to the third embodiment of the present invention. In the present embodiment, the difference from the first embodiment shown in FIG. 1 is that a MOSFET 7 is used instead of the diode D3.
[0034]
By using a diode generated between the drain and source, having the same function as the diode D3, applying a voltage to the gate of the MOSFET 7 during continuous operation, and turning on the drain and source, the loss can be reduced. I am trying.
[0035]
【The invention's effect】
As described above, according to the present invention, the DC component generating secondary winding of the transformer, the diode connected in series to the input side of the DC component generating secondary winding, the diode, and the DC component generating 2 A direct current generating circuit comprising a capacitor connected in parallel to the next winding and generating a direct current component having a voltage higher than the power supply input voltage, and a pulse for superimposing a pulse voltage on the direct current component generated by the direct current generation circuit The voltage superimposing circuit is provided.
[0036]
With this configuration, it is possible to provide a discharge lamp lighting device that can suppress the voltage peak value at the time of starting the discharge lamp and reduce the size and weight of the high-voltage generating transformer to be used.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a discharge lamp lighting device according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a lamp lighting operation waveform in the discharge lamp lighting device.
FIG. 3 is a circuit diagram of a discharge lamp lighting device according to a second embodiment of the present invention.
FIG. 4 is a circuit diagram of a discharge lamp lighting device according to a third embodiment of the present invention.
FIG. 5 is a circuit diagram of a conventional discharge lamp lighting device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Control circuit part 2 Pulse voltage generation circuit 3 Transformer for high voltage pulse voltage generation (T1)
4 Chopper circuit 5 Discharge lamp 6 DC generation circuit 7 MOSEFT
P1 Primary winding S1 Transformer secondary winding S2 DC component generation secondary winding S2 Pulse voltage generation secondary windings D2 and D3 Diode C3 Capacitor VIN Power supply input voltage RL1 Short relay

Claims (5)

A discharge lamp;
A chopper circuit that converts the power input voltage into the voltage and current required for operation;
A pulse voltage generation circuit for supplying a constant voltage and current;
In a discharge lamp lighting device comprising a transformer for supplying a high voltage to the discharge lamp,
The DC component generating secondary winding of the transformer, a diode connected in series to the input side of the DC component generating secondary winding, and the diode and the DC component generating secondary winding in parallel A direct current generating circuit for generating a direct current component having a voltage higher than the power input voltage,
A discharge lamp lighting device comprising a pulse voltage superimposing circuit that superimposes a pulse voltage on a DC component generated by the DC generating circuit. 2. The discharge lamp lighting device according to claim 1, wherein the pulse voltage superimposing circuit has a secondary winding for generating a pulse voltage provided on the secondary winding side of the transformer, and the secondary winding for generating the pulse voltage. A discharge lamp lighting device characterized in that a wire is connected in series with the output side of the secondary winding for generating a DC component. 2. The discharge lamp lighting device according to claim 1, wherein a bypass diode is connected in parallel to a diode connected in series to the input side of the secondary winding for generating the DC component, and a current path at the time of lighting is A discharge lamp lighting device characterized by being configured to be bypassed by a bypass diode. 4. The discharge lamp lighting device according to claim 3, wherein a relay is connected in parallel to the bypass diode and is short-circuited by the relay. 2. The discharge lamp lighting device according to claim 1, wherein a MOSFET is connected in parallel to a diode connected in series to the input side of the secondary winding for generating the DC component, and a voltage is applied to the gate of the MOSFET during continuous operation. A discharge lamp lighting device characterized by applying a voltage between the drain and the source to turn on.

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