JPS6364295A - Discharge lamp electric source - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a discharge lamp power supply device for pulse-lighting a xenon discharge lamp, etc., and in particular to a discharge lamp power supply device that always supplies constant power even when input voltage fluctuates. The present invention relates to a discharge lamp power supply device that can perform

[Traditional technique management i]

FIG. 10 is a circuit diagram of a conventional discharge lamp power supply device for pulse-lighting a xenon discharge lamp. In Figure 10,
51 is an AC chamber, B is 52 is a leakage transformer, 53 is a charge/discharge capacitor, 54 is a supersaturation reactor, 55 is a lamp starting circuit, and L is a xenon discharge lamp.

According to the above circuit configuration, the AC voltage of the AC power source 51 is made into a pulse waveform by the leakage transformer 52, the capacitor 53, and the leakage reducing actuator 54. Pulse current with the waveform shown (
The discharge voltage i=l + can be Lζ.

-S-wise, it is known that when a pulse current is passed through the xenon discharge lamp L, the amount of light is 2 to 3 times the normal luminous efficiency. , since the supersaturation reactor 54 is arranged, the device becomes large, heavy, and expensive, and furthermore, there is no constant power property. Therefore, such devices are not contradictory in industry.

FIG. 12 is a circuit diagram of a conventional discharge lamp power supply device using a bidirectional switching element (hereinafter referred to as a triac) instead of a supersaturation reactor. In FIG. 12, 51 to 53 and L are the same as the 10th concave, 56 is a triac, 57 is a comparison pulse generation circuit (P, C),
58 is a current I output device for detecting the current of the xenon discharge lamp L, 59 is a pulse transformer, 6Q is a starting circuit for the discharge lamp, and 61 is a bypass resistor. In addition, the resistor 62
and capacitor 63 are RC snubber circuits for protecting the triac from overvoltage when the triac is turned off.

According to the above circuit configuration, the current detector 58 of the xenon discharge lamp L outputs the discharge current I★ of the xenon discharge lamp L, and based on the result, the comparison pulse generation circuit 5
7 controls the phase of the trigger pulse sent to the gate of the triac 56, and adjusts the timing when the triac 56 becomes conductive.

That is, when the discharge current of the xenon discharge lamp I4 is large, the conduction time of the triac 56 is shortened, and when the discharge current is low, the conduction time of the triac 56 is lengthened. By controlling the phase, constant power is supplied to the xenon discharge lamp L.

In addition, while the triac 56 is in a non-conductive state, a bypass resistor 6 is provided to prevent the xenon discharge lamp L from going out.
Power is supplied via 1. In this way, the 11th
A pulse current with a waveform similar to that shown in the figure is supplied to the xenon discharge lamp. Incidentally, according to the above circuit configuration, i! Since there is no spore reactor, the device can be made smaller and lighter.

(Problems to be Solved by the Invention) However, in the conventional discharge lamp power supply device, the lamp power supplied to the xenon discharge lamp L is the product of the lamp voltage and the lamp current. If the voltage is controlled to be a constant current, there is a drawback that if the lamp voltage increases, it will cause excessive input.For example, in terms of -i, discharge lamps such as xenon discharge lamps ?At the end of the life of the discharge lamp, the lamp voltage drops to 1 level.For this reason, if you control the lamp current so that it remains constant as in the conventional discharge lamp power supply device, the lamp power will drop at the end of the discharge lamp's life. The temperature of the discharge lamp increases,
As a result, the lamp voltage increases, and as a result, the lamp power further increases α, so the phenomenon that the lamp voltage increases, the lamp power increases, and this again increases the lamp voltage repeats, and eventually, the xenon discharge lamp L
This will result in extremely excessive input, leading to accidents such as destruction of the xenon discharge lamp L.

The invention was made based on the above circumstances, and is designed to prevent over-input even if the lamp voltage increases, and to always maintain constant power to the discharge lamp even if the input terminal fluctuates. The purpose of the present invention is to provide a discharge lamp unit 5 that can supply the following.

[Failure to solve the problem]

To achieve the above object, the present invention provides an AC power supply and a charging IJ connected to the AC power supply via a current limiting impedance element.1. Electrical capacitor and load force '1.
a bidirectional switching element for supplying electric power from the alternating current power supply and the charge/discharge capacitor to the discharge lamp via a starting means for supplying the electric power from the AC power supply and the charge/discharge capacitor to the discharge lamp; and a detection means for detecting an input voltage. , a phase control circuit that controls the phase of a trigger pulse applied to the gate of the bidirectional switching element based on the output signal of the peak means;
and a bypass circuit that supplies power to the discharge lamp when the bidirectional switching element is in a non-conducting state.

[Effect]

With the above configuration, the present invention detects the input voltage supplied to the discharge lamp, and when the input voltage fluctuates, adjusts the phase of the trigger pulse applied to the gate of the bidirectional switching element to emit light. Electric lamps can always be supplied with constant power even if the input voltage fluctuates, and since the input voltage is detected and constant power is supplied to the discharge lamp, it is possible to supply constant power to the discharge lamp at the end of its life. Thus, when the discharge lamp voltage increases, the discharge lamp power can be reduced.

(Example) A first example of the present invention will be described below with reference to FIGS. 1 to 6. FIG. 1 is a circuit diagram of a discharge lamp type A device which is a first embodiment of the present invention. In Fig. 1, 1 is an AC TUB, 2 is an AC handle, 3 is a charging/discharging capacitor, and 4 is a charging/discharging capacitor.
5 is a pulse transformer for starting the discharge lamp, and 5 is the lamp starting circuit (P.

G), 6 is triac, 7 is bypass resistor, 8a is R
Resistor for C snubber circuit, 8b is a capacitor for RC snubber circuit, 9 is comparison pulse generation circuit (P, C), 10
is the input voltage detection circuit (V.

D), 11 is the input switch, 12 is the delay relay (T, D
), 12a is a contact of the delay relay 12, and L is a discharge lamp.

Next, the operation of the circuit configured as described above will be explained. First, when the manual switch 11 is turned on, a pulse voltage is generated by the pulse transformer 4 and the starting circuit 5.

However, since the triac 6 is still in a non-conducting state, no current flows to the discharge lamp L, and a charging current flows to the charging/discharging capacitor 3 during the half cycle until the discharge lamp L lights up. When the try book 6 becomes conductive due to the trigger current from the comparison pulse generation circuit 9, a current flows from the AC power supply 1 through the reactor 2;
A combined current with the discharge current of the charge/discharge capacitor 3 flows through the discharge lamp L. This discharge current of the charging/discharging capacitor 3 generates a peak value of the luminous flux. Eventually, when the voltage of the AC power supply 1 is reversed and the triac 6 becomes non-conductive,
Until the triac 6 becomes conductive again in the next half cycle by the trigger current from the comparison pulse generation circuit 9, the discharge lamp L has already started, so the discharge lamp is connected in parallel with the triac 6. A bypass current flows through a bypass resistor 7 connected to the bypass resistor 7. This is to prevent the discharge lamp L from cooling down and causing the restriking voltage to rise and going out. After a certain period of time,
Since the discharge of the discharge lamp L becomes stable and the pulse voltage from the pulse transformer 4 is no longer necessary, the delay relay 12 operates, its contact 12a becomes open, and the generation of the pulse voltage is stopped. After stopping the generation of the pulse voltage, a discharge current similar to the waveform shown in FIG. 11 can be obtained by sending a trigger current to the triafcro every half cycle to make it conductive.

By the way, the phase angle φ of the trigger current applied to the triac 6 is such that as Φ increases, the power supplied to the discharge lamp L decreases, and conversely, as Φ decreases, the power supplied to the discharge lamp L decreases.
The amount of power supplied to the Assume now that, as shown in FIG. 2, the phase angle of the trigger current when the input voltage is normal (Vz...) is, for example, Φ. If, for some reason, the input voltage increases as shown by the solid line (22 degrees) in FIG. 2, the input terminal detection circuit 10 detects this and sends a signal to the comparison pulse generation circuit 9. The comparison pulse generation circuit 9 receives this signal and sends to the triac 6 a trigger pulse with a trigger phase angle of 2, which is larger than the normal Φ1.

This can prevent an increase in power consumption of the discharge lamp L due to an increase in input voltage.
On the other hand, for some reason, the dotted line in Figure 2 (V+*.)
When the input voltage falls as shown by , the input voltage detection circuit 1O detects this and sends a signal to the comparison pulse generation circuit 9. The comparison pulse generation circuit 9 receives this signal and sends a trigger pulse with a trigger phase angle smaller than the normal Φ to the triancro. Thereby, it is possible to prevent the input voltage from decreasing and the IJ power of the discharge lamp L from decreasing.

In this way, according to the embodiment with the above configuration, the twelfth
As shown in the figure, the conventional device detects the discharge current of the discharge lamp and controls the phase angle of the trigger pulse applied to the triac so that the discharge current remains at a constant value.As a result, the discharge lamp receives constant power. It detects the input terminal to the discharge lamp and controls the phase angle of the trigger pulse applied to the triac, thereby supplying constant power to the discharge lamp, so the lamp power due to the increase in lamp voltage It is possible to suppress the rise in

That is, in the conventional discharge lamp power supply device shown in FIG. 12, in order to supply constant power to the discharge lamp, it is assumed that the lamp voltage is constant.

For this reason, the conventional device has the disadvantage that when the lamp voltage increases, the lamp power also increases in proportion to the lamp voltage, as shown by the straight line (A) in FIG. On the other hand, in the Kino IH example of discharge power a device, when the lamp voltage on the discharge lamp side increases, the lamp current decreases, and when the lamp voltage decreases, the lamp current increases, and is basically reactor control. , and is an open-loop feedback circuit that follows only changes in the input voltage. Therefore, when the input voltage is used as a parameter, the relationship between lamp voltage and lamp power becomes as shown in curves (b), (c), and (d) in Figure 3, and as the lamp voltage increases, the lamp power It can be seen that the amount decreases.

Next, the above will be explained using mathematical formulas. In the conventional discharge lamp power supply device shown in FIG. 12, the lamp voltage VZ is constant, and since it is an open loop feedback circuit, the lamp N current IQ is also constant.

Therefore, lamp power Wf! When the power factor is CO3θ2, Wl=Vl×IAcos81. Therefore, the lamp voltage ■β is ΔVl! When the power is changed to i, the lamp power Wl also changes by a ratio of ΔVl in proportion to the change, resulting in a straight line as shown in FIG. 3(a).

On the other hand, since the device of this embodiment basically lights the lamp side by the acdle, if the circuit shown in Fig. 1 is simplified, it can be considered that it is equivalent to the circuit shown by the solid line in Fig. 4. can. Therefore, the curve of lamp voltage and lamp current of the device of this embodiment becomes a substantially quadratic curve as shown in FIG. A no-load voltage ■1 equal to the input voltage occurs between the terminals of . Further, the rating is stable at Ve and le. This can be easily obtained by experiment. Therefore, the lamp current is 11'=-cxVj! ” +Is (ex: constant), and the lamp power is ~¥7!=II!・
Vj! -cos θ, the lamp power is Wl-(
-α■β' +l5Vn)CO3θ, and the relationship between lamp voltage ■2 and lamp power V/Q becomes a cubic curve.

That is, the relationship between lamp voltage Vβ and lamp power Wl approximates a cubic curve shown by the solid line in FIG. Here, in the circuit of the device of this embodiment, a charging/discharging capacitor is actually inserted in parallel with the lamp, so if we consider the state in which the charging/discharging capacitor C0 is directly connected to the circuit shown in FIG. , where the lamp voltage is low, due to the resonance voltage ■2 between the reactor 2° and the charge/discharge capacitor C0, the discharge current of the charge/discharge capacitor C0 and the base current from the input side flow even more than the rated current. Therefore, the lamp power increases, and conversely, the lamp power decreases when the lamp voltage is high. Therefore, the tertiary line showing the relationship between lamp voltage and lamp power has a maximum current when the lamp voltage is low, as shown by the dashed line in FIG. 6, to be exact.

As a result of experiments, when there is no charging/discharging capacitor C0, the lamp power reaches its maximum value at about 55% of the no-load voltage. On the other hand, when there is a charging/discharging capacitor C0, the maximum power is at about 1536 points of the resonance voltage between the reactor 2° and the charging/discharging capacitor C6. Therefore, if the device of this embodiment is used in a xenon discharge lamp, etc., which has a low lamp rated voltage and a high starting voltage, the maximum power will be reached at a low lamp voltage, and the lamp voltage will be high, even though the no-load voltage is high. Since the lamp power decreases as the lamp increases, for example, even if the lamp voltage increases at the end of the lamp's life, overpower does not occur. Furthermore, since an open loop feedback circuit is provided that detects fluctuations in input voltage and maintains constant power performance, stable constant power performance can be maintained without being affected by instability of lamp discharge.

As described above, unlike the closed-loop feedback method that detects the discharge current of the discharge lamp and makes it constant power, the device of this embodiment uses the open-loop feedback method that detects the input voltage to the discharge lamp and makes it constant power. Therefore, like a closed loop feedback method,
There is no malfunction due to instability of lamp discharge, and in addition to the open loop feedback method, the lamp power is maximized at the lowest lamp voltage due to the resonance voltage between the charge/discharge capacitor and the accelerator. Even if the lamp voltage increases at the end of the lamp's life, it is possible to prevent Ar4 power from being applied. Further, since the device of this embodiment can light the lamp by effective pulse current by controlling the phase of the bidirectional switching element, it has great industrial effects as a power source for photolithography and copying.

FIG. 7 is a circuit diagram of a discharge lamp power supply device according to a second embodiment of the present invention. The second embodiment differs from the first embodiment in that a bypass resistor 7 is connected in parallel to both ends of the reactor 2 and the triafcro. Further, the functions and effects of the second embodiment are similar to those of the first embodiment.

FIG. 8 is a circuit diagram of a discharge lamp power supply device according to a third embodiment of the present invention. The third embodiment differs from the first embodiment in that a step-up transformer T is disposed on the negative side. Third
According to the embodiment, it is possible to reliably control the lighting of discharge lamps that have particularly poor startability or discharge lamps that have a relatively high rated voltage. Other functions and effects are similar to those of the first embodiment.

FIG. 9 is a circuit diagram of a discharge lamp power supply device according to a fourth embodiment of the present invention. The fourth embodiment differs from the first embodiment in that a leakage transformer Tf is used instead of a step-up transformer and a choke on the negative side. The operations and effects of the fourth embodiment are similar to those of the third embodiment.

Incidentally, in the above embodiment, a case has been described in which a resistor is used in the bypass circuit, but the present invention is not limited to this, and this may be an impedance or an actuator.

〔Effect of the invention〕

As explained above, according to the present invention, the input voltage is detected and the bidirectional switching element is controlled according to the fluctuation, so that even if the input voltage fluctuates, the discharge lamp remains constant. Accordingly, it is possible to provide a discharge lamp power supply device that can supply electric power of 100% and that does not cause excessive input to the discharge lamp even when the discharge lamp voltage increases.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a discharge kT power supply device according to the first embodiment of the present invention, FIG. 2A is a diagram showing the input voltage waveform of the discharge lamp, and FIG. WIt
), Figure 4 is a simplified circuit diagram of the circuit in Figure 1, and Figure 5 is a diagram showing the relationship between lamp voltage (vg and lamp current (1
1), FIG. 6 is a diagram showing the relationship between lamp voltage (vl) and lamp power (Wl), FIG. 7 is a circuit diagram showing the second embodiment, and FIG. 8 is a diagram showing the relationship between lamp voltage (vl) and lamp power (Wl). FIG. 9 is a circuit diagram showing the fourth embodiment, FIGS. 10 and 12 are circuit diagrams of a conventional discharge lamp power supply device, and FIG.
FIG. 1 is a diagram showing a discharge current waveform of a discharge lamp in the conventional discharge power supply 7FA device shown in FIG. DESCRIPTION OF SYMBOLS 1... AC power supply, 2... Reactor, 3... Charge/discharge capacitor, 4... Pulse transformer, 5... Starting circuit, 6... Triac, 7.0. Bypass resistor, 8a...Resistor, 8b...Capacitor, 9...
Comparison pulse generation circuit, 10... Input voltage detection circuit, 1
1...Input switch, 12...Delay relay, L...
・Discharge lamp. 10 pieces, 2 pieces of flute? '5Z Note 4 Σ Atsushi 5 → Shit (Runf '1st) - 2yo death, N No. 6 No. 7 No. 8 No. 9

Claims (3)

[Claims] (1) An AC power supply, a charging/discharging capacitor connected to the AC power supply via a current limiting impedance element, a discharge lamp as a load, and discharging the power of the AC power supply and the charging/discharging capacitor to the discharge lamp. a bidirectional switching element for supplying via a starting means for starting the lamp; a detection means for detecting the input voltage; and a trigger pulse for applying to the gate of the bidirectional switching element based on the output signal of the detection means. A discharge lamp power supply device comprising: a phase control circuit that controls the phase of the discharge lamp; and a bypass circuit that supplies power to the discharge lamp when the bidirectional switching element is in a non-conducting state. (2) The starting means includes a pulse transformer for starting;
2. The discharge lamp power supply device according to claim 1, comprising a starting circuit and a delay relay that cuts off the supply of power to the starting circuit after a certain period of time has elapsed after the start of energization of the discharge lamp. (3) The bypass circuit is made of a resistor, and is configured to allow a current smaller than a main current flowing through the discharge lamp to flow through the discharge lamp when the bidirectional switching element is in a non-conducting state. The discharge lamp power supply device according to claim 1 or 2, wherein the discharge lamp power supply device is connected in parallel to a switching element.