JPS5815918B2 - HOMEMAN TENKOKIYUDENSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises two input terminals adapted to be connected to an alternating current voltage source with a frequency below 100 Hz, both input terminals being connected to the ignition center of a discharge lamp with preheated electrodes. Both are interconnected in a series circuit of the stabilizing inductance and the discharge lamp, and the terminals of the discharge lamp electrodes on the opposite side from the AC voltage source side are closed during the first part of the discharge lamp ignition process to determine the lighting state of the discharge lamp. The present invention relates to an ignition power supply device for a discharge lamp comprising preheating electrodes interconnected by a starting device comprising a semi-opening semiconductor switch.

Examples of discharge lamps equipped with preheated electrodes include low-pressure mercury vapor discharge lamps.

In interpreting the above expression "ignition process of the discharge lamp", it should be noted that the ignition process starts at the moment the device is connected to the AC voltage source and ends with complete ignition of the discharge lamp.

Known devices of the above-mentioned type are disclosed, for example, in US Pat. No. 3,643.
It is described in the specification of No. 127.

In this known device, the semiconductor switch consists of a thyristor or a triac, which conducts during each suitable half-cycle of the alternating current voltage source during the ignition process of the discharge lamp to supply a preheating current to the discharge lamp electrodes until the discharge lamp is ignited. It is possible to flow to

The reliability of starting a discharge lamp with this known device is higher than when using previously known glow discharge starting devices provided with moving contacts, but this advantage is due to the fact that the thyristor or triac has the advantage that the current flowing through it is approximately This is offset by the fact that it always becomes non-conducting the moment it becomes zero.

This means that in the device according to US Pat. No. 3,643,127, voltage peaks that favor the ignition of the discharge lamp cannot occur due to the stabilizing inductance connected in series with the discharge lamp.

A stabilizing inductance (which may or may not be coupled to a capacitor) is also referred to as a ballast.

Because of this absence of voltage peaks, the discharge lamp of the known device must be ignited at a voltage that is at most equal to the peak value of the voltage of the alternating voltage source.

This requirement is particularly difficult to meet for older discharge lamps, making ignition unreliable.

As a result, ballasts formed as leaky transformers are often used.

However, the disadvantage of such a transformer is that it makes the lamp ignition power supply expensive.

The object of the present invention is to provide an electronic discharge lamp starting method, which allows a peak voltage greater than the peak value of the voltage of the alternating current voltage source to be generated across the discharge lamp for its ignition using a simple stabilizing inductance. We are trying to provide the equipment.

The invention comprises two input terminals adapted to be connected to an alternating current voltage source with a frequency below 100 Hz, both input terminals being connected to a stabilizing inductance and an inductor for starting a discharge lamp with preheating electrodes. The discharge lamps are interconnected in a series circuit, and the terminals of the discharge lamp electrodes opposite to the AC voltage source side are equipped with semiconductor switches which are closed during the first part of the ignition process of the discharge lamp and open during the lighting state of the discharge lamp. In the ignition power supply device for a discharge lamp, the semiconductor switch is a transistor, and a control circuit is connected to the base of the transistor, and the control circuit includes a resistor and a resistor. A charging/discharging circuit consisting of a series circuit of a capacitor and a voltage threshold element connected between a common connection point of the resistor and the capacitor and the base of the transistor is provided, and a time constant of the series circuit of the resistor and the capacitor is provided. is characterized in that during the ignition process the transistor is made conductive and non-conductive at least several times during each half-cycle of the alternating voltage source.

The advantage of the device of the present invention is that the starting device of the device does not have a movable contact part, and by controlling the transistor as described above, a high peak voltage can be generated rapidly and continuously across the discharge lamp. This means that the discharge lamp can be reliably ignited.

In the device according to the invention, two or more discharge lamps provided with preheating electrodes can be provided and these can be ignited alternately, for example by the same transistor starting device.

The control circuit of the transistor is connected to its own voltage source, for example a battery integrated in the starting device.

In a preferred embodiment of the device according to the invention (see FIG. 1), the control circuit of the transistor 17 is provided with a breakdown element 21 as a voltage threshold element connected to the base of this transistor, and further includes a first resistor 19 and a first resistor 19. A series circuit of capacitors 20 is provided, the terminal of this breakdown element 21 opposite the transistor is connected to the connection point of the first resistor 19 and the first capacitor 20, said series circuit 19.20 associated with the control circuit.
is shunted by the transistor 17, and at least the breakdown element 21 and the first capacitor 20 are shunted by the second resistor 18;
A diode 12 is inserted into the connection line between the discharge lamp 5 and the first capacitor 20 with its conduction direction matching the conduction direction of the transistor 17.

The advantage of this embodiment is that there is no need for a battery in the starting device, since the control circuit of said transistor 17 is powered from an alternating voltage source.

Another advantage of this embodiment is that the transistor 17 can be turned on and off at high speed by its simple control circuit to obtain voltage peaks across the lamp.

The first capacitor 20 includes a diode 12 and a first resistor 19.
It is rapidly charged through this process, and when it reaches the threshold voltage of the breakdown element 21, it is rapidly discharged again.

In another preferred embodiment of the device of the present invention, the time constants of the charging/discharging circuits 19, 20, and 21 of the control circuit are determined by adjusting the frequency of the current flowing through the middle box 1 transistor 17 at the end of the ignition process of the discharge lamp 5 and the AC voltage source. The quotient with the frequency is 10 to 10000, especially 2
Shorten it to between 0 and 2000.

The advantage of this preferred embodiment is that the frequency at which transistor 17 turns on and off is relatively high, so the frequency of the peak voltage is also high and the discharge lamp ignites quickly.

This is because a peak voltage is generated for ignition at the same time that the discharge lamp reaches a state suitable for ignition (a state in which the electrodes are brought to a sufficient temperature).

In a further embodiment of the invention, the breakdown voltage of the breakdown element 21 is selected between the actual value of the voltage of the alternating voltage source and the operating voltage of the discharge lamp.

The advantage of this example is that no other auxiliary devices are required to deactivate the starting device after ignition of the discharge lamp.

In another particular embodiment of the invention, the starting device is provided with a second transistor 22 whose base is connected to a branch of a second time circuit 23.24, which second time circuit is connected to the second transistor 22.
The branch of the second time circuit 19, 20 is connected in parallel with the first time circuit 19, 20, and the main electrode circuit of the second transistor 22 is connected in parallel with the first time circuit 19, 20.
The time circuit 19,20 is electrically connected in such a way that for a change in the conduction state of the second transistor, a control voltage is applied to the base of the first transistor 17, causing the first transistor 17 to become non-conducting.

The advantage of this particular example is that if the discharge lamp is defective, the starting device will become inoperative after some time.

This is because the fast change in the control voltage at the base of the first transistor 17 is blocked by the second transistor 22 after a while.

In this case, if the first transistor 17 is rendered non-conducting, the starting device is deactivated apart from a small current flowing through the control circuit.

This has the advantage of reducing the generation of radio interference waves, for example.

In the particular example above, it is preferred to shunt the first capacitor 20 with the second transistor 22.

In yet another specific example of the device of the invention, the starting device is provided with bridge rectifiers 9 to 12, the input terminals of which are connected to the discharge lamp electrodes 3.
, 4 to terminals 7, 8 opposite the AC voltage source, and the main electrode of the first transistor 17 to the output terminal 13.14 of this bridge.

The advantage of this example is that the starter transistor 17 can be activated in both even and odd half cycles of the alternating voltage source.

In the particular example described above, in which the starting device comprises two transistors 17.22, the second time circuit is constituted by a series circuit of a third resistor 23 and a second capacitor 24, with the base of the second transistor 22 being It is connected to the connection point between the third resistor 23 and the second capacitor 24 via four resistors 25 .

The advantage of this example is that the time circuit 23 .
24 is extremely simple.

This is important since the entire starting device must be accommodated within a minimum space.

In this example starting device, it is preferable to shunt the second capacitor 24 with the fifth resistor 26.

The advantage is that this second capacitor 24 can be discharged via this fifth resistor 26 when switching off the device.

As a result, the device is immediately ready for the next ignition of the discharge lamp.

In a further preferred embodiment of the invention, the first capacitor 20 is shunted by a sixth resistor, which resistor is a resistor 30 with a large temperature coefficient (see FIG. By making the first resistor 19 a resistor 31 having a large temperature coefficient (see Fig. 6), the voltage across the first capacitor 20 is reduced after current flows through these resistors and when the discharge lamp is not ignited. The voltage between them is set to be lower than the limit voltage of the breakdown element 21.

The advantage of this example is that the starting device can be deactivated without the use of a second transistor both when the discharge lamp is ignited and when the discharge lamp is out of ignition.

This means that the current flowing through these type side connection resistors 19 and 30 or 31 and 32 changes the voltage division value of these resistors, even if the voltage across this series resistor circuit corresponds to a misfired discharge lamp. This is because the first transistor is turned off in order to change the voltage across the capacitor 32 (therefore, the voltage across the first capacitor 20) to be below the limit voltage of the breakdown element 21.

This starting device requires only one transistor.

When the sixth resistor 30 is a resistor with a large temperature coefficient, this resistor is a resistor with a negative temperature coefficient.

During the entire ignition process of the discharge lamp, the transistor 17 can be made conductive and non-conductive at a relatively high frequency.

It is likewise possible to keep transistor 17 conductive during the first part of the discharge lamp ignition process to rapidly heat up the discharge lamp electrodes, and only then to initiate the rapid conduction and non-conduction changes of transistor 1T. .

In this case, the peak voltage occurs only when the discharge lamp electrode has already reached the nominal temperature.

Generally, this is advantageous for the lifetime of the discharge lamp.

In fact, ignition when the two electrodes are cold causes them to age rapidly and blackens the lamp vessel.

In a specific example of the apparatus of the present invention (see FIG. 7) in which the discharge lamp can be ignited when the electrodes are at a high temperature, the main electrode of the third transistor 35 is connected to the main electrode circuit of the first transistor 17. Provided to form part of a series circuit of the first resistor 19 and the first capacitor 20 connected in parallel,
The base of this third transistor is connected to a time circuit 37-40, the time constant of which is made so long that this third transistor conducts only a few periods after the alternating voltage source has been switched on.

An advantage of this example device is that charging of the first capacitor 20 in the control circuit of the first transistor 17 is initially blocked by the non-conducting third transistor 35.

As a result, the control of the first transistor 17 is primarily determined by the voltage division between the first resistor 19 and the second resistor 18 in conjunction with the breakdown element 21 .

Its value can be adjusted so that the first transistor 1T is conductive almost all the time.

As a result, satisfactory preheating of the discharge lamp electrodes can be easily obtained.

The particular example of the device according to the invention described above can be further improved by shunting the first capacitor 20 with a resistor 30 having a negative temperature coefficient.

The advantage is that this starting device also stops automatically.

A specific example of the device of the present invention comprising a third transistor includes at least a blind side circuit of a second diode 40, a seventh resistor 39 and a third capacitor 37 in the control circuit of the third transistor 35, A further improvement can be achieved by connecting one end of the circuit to the connection point between one input terminal 1 of the device and a stabilizing inductance 6 connected thereto.

The advantage of the improved example of the present invention described above is that the control voltage for the third transistor 35 in the short circuit state of the first transistor 17 can be easily generated.

Of course, during the short-circuit condition of the first transistor 1T, the control voltage of the third transistor 35 can also be generated by a voltage taken from another part of the current flowing through the main electrode circuit of the first transistor 17.

For example, it can be tapped off by an auxiliary control transformer within this main electrode circuit.

The invention will be explained with reference to the drawings.

In FIG. 1, 1 and 2 are, for example, 200 volts and 50 volts.
This is an input terminal of the device of the present invention which is connected to the main line of H2.

The input terminal 1 is connected via a stabilizing inductor 6 to an electrode 3 of a low-pressure mercury vapor discharge lamp 5.

The input terminal 2 is connected to the electrode 4 of this discharge lamp 5.

The electrodes 3 and 4 of the discharge lamp 5 are of a preheating type. Electrodes 3 and 4
Connect the terminal opposite to input terminals 1 and 2 of the diode bridge (diodes 9, 10° 11.12) to input terminal 7
and connect to 8.

The output terminals 13 of the diode bridges 9 to 12 are connected to a conducting wire 15.

This conductor 15 has a positive potential due to the diode bridges 9-12.

Connect the output terminals 14 of the diode bridges 9 to 12 to the conductor 16
Connect to.

This conductor 16 has a negative potential due to the diode bridges 9-12.

NPN type first transistor 17 (ignition transistor)
is placed between the conducting wires 15 and 16, and its collector is connected to the positive conducting wire 15 and its emitter is connected to the negative conducting wire 16.

The base of transistor 17 is connected to resistor 18.

The other end of this resistor is connected to the conducting wire 16.

Furthermore, the control circuit of the transistor 17 is connected to the first resistor 19 and the first resistor 19.
It is constructed with a time circuit consisting of a series connection circuit of capacitors 20.

This series connection circuit is placed between conductors 15 and 16.

The connection point between the resistor 19 and the capacitor 20 is connected to the base of the transistor 17 via a breakdown element 21 as a voltage threshold element formed as a diac.

Similarly, one main electrode (collector) of the second npn transistor 22 (switch-off transistor) is connected to the connection point between the resistor 19 and the capacitor 20.

The emitter of transistor 22 is connected to conductor 16.

The second time circuit of the transistor 22 is constituted by a series circuit of a resistor 23 and a capacitor 24.

This series circuit is connected between conductors 15 and 16.

The connection point between the resistor 23 and the capacitor 24 is connected to the base of the transistor 22 via another resistor 25.

Further, the capacitor 24 is shunted by a discharge resistor 26.

The operation of the apparatus of FIG. 1 is as follows.

When connecting terminals 1 and 2 to an alternating voltage source, discharge lamp 5 initially remains extinguished.

DC voltage (full wave rectified voltage) is applied to inductor 6 and conductor 15
and 16 are generated by the diode bridges 9-12.

Initially, transistor 17 is cut off.

Capacitor 20 is charged via resistor 19 until the voltage across it reaches the value of the breakdown voltage of diac 21.

Diac 21 then breaks down and the base of transistor 17 receives a positive voltage on its emitter.

This transistor therefore becomes conductive and a preheating current begins to flow to the electrodes 3 and 4 of the discharge lamp 5.

This current is the circuit 1,6,3,9,13゜17.14,1
It flows through 2 and 8.

This current flows from terminal 2 to electrode 4 to terminal 8 to diode 11.
, transistor 17, terminal 14, diode 10, terminal 7, electrode 3, inductor 6, and flows in the opposite direction to terminal 1.

When the diac 21 conducts current, the capacitor 20 is discharged, a portion of which is passed through the resistor 118.

As a result, diac 21 becomes non-conductive after a short time.

Then transistor 17 also cuts off the current again.

The first action is then repeated again.

That is, capacitor 20 begins to be charged via resistor 19.

In this way, transistor 17 is rendered conductive and non-conductive in sequence very quickly.

The current flowing through electrodes 3 and 4 during the conduction period of transistor 17 heats these electrodes to a temperature at which the discharge lamp can be ignited.

At a given instant, the voltage peak generated by the inductor 6 at the moment when the transistor 17 becomes non-conducting is large enough to ignite the discharge lamp 5.

After the discharge lamp 5 is ignited, the control of the transistor 17 is maintained for a while.

However, in this case the resulting voltage peaks between electrodes 3 and 4 are significantly smaller.

The reason for this is that the current flowing through the inductor 6 is no longer completely interrupted.

A while after the discharge lamp 5 is ignited, the transistor 22 becomes conductive.

The reason for this is that the capacitor 24 of the time circuit 23, 24, which has a long time constant, obtains a charge that makes the transistor 22 conductive.

This transistor becomes a short circuit for capacitor 20.

As a result, transistor 17 permanently returns to its non-conducting state.

During the operating state of the discharge lamp 5, the capacitor 24 retains its voltage.

In order to obtain a satisfactory re-ignition of the discharge lamp 5 after switching it off, the capacitor 24 of the arrangement of FIG. 1 is shunted with a resistor 26.

In practice, when switching off the device of FIG. 1, this capacitor 24 is discharged via the resistor 26.

The device is thus ready to switch on the discharge lamp 5 again.

The presence of transistor 22 and associated control circuitry is important in making the device as radio-interference free as possible.

The advantage of the device of FIG. 1 is that even if the discharge lamp 5 is defective, the transistor 22 will conduct after a while, disabling the starting device.

In FIGS. 2-4, En indicates the power supply voltage as a function of time.

Only one cycle of the power supply voltage is shown. In FIG. 2, the vertical line indicates the peak voltage generated by the transistor 17 between the discharge lamp electrodes 3 and 4.

In one example, the peak voltage of these peaks increases to 700 volts.

FIG. 3 shows the state before the transistor 22 becomes conductive after the discharge lamp is ignited.

As is clear from this, the vertical line indicating the peak voltage becomes significantly smaller in this case.

In FIG. 4, the solid line shows the voltage between electrodes 3 and 4 as a function of time, which is the normal operating voltage of the discharge lamp.

In one example, the discharge lamp 5 is a 40 watt low pressure mercury vapor discharge lamp provided with a phosphor layer.

The inductance of the ballast 6 was approximately 1 Henry.

The resistor 18 was approximately 1M ohm.

Resistor 19 was approximately 15 ohms.

The capacitance of the capacitor 20 was approximately 10 nanofarads.

The resistor 23 is about 1M ohm, and the capacitor 24 is about 10
It was set to 0 microfarads.

Resistors 25 and 26 had a value of approximately 27 ohms.

The peak frequency was approximately 25 KHz.

Depending on the input voltage between terminals 1 and 2, the discharge lamp 5 is approximately 1/3
Ignition occurred within ~1/2 second.

Transistor 22 supplies voltage to the device after approximately 5 to 8
It became conductive after a few seconds.

The apparatus shown in FIG. 5 largely corresponds to the apparatus of FIG.

Corresponding parts are therefore designated by the same reference numerals. The difference between the device of FIG. 5 and the device of FIG. 1 is that the second transistor 22 is not present in the device of FIG.

This is compensated for in the arrangement of FIG. 5 by providing a resistor 30 that shunts capacitor 20.

Resistor 30 has a large temperature coefficient.

This resistor is assumed to have a negative temperature coefficient (NTC).

The operation of the apparatus of FIG. 5 is initially the same as that of FIG.

In this example as well, the starter supplies voltage between terminals 1 and 2 and then stops after a while.

The reason for this is that, even in the case of FIG. This is because the value is such that it is possible to generate a voltage lower than the breakdown voltage of .

Since the initial resistance value of the NTC resistor 30 is extremely high, it reaches the breakdown value of the diac 21 in the initial state.

This is the transistor 17 as explained in connection with FIG.
is an initial state in which conduction and non-conduction occur at high speed.

The NTC resistor 30 can also be replaced with a normal resistor.

This resistance does not have a large temperature coefficient.

If the partial voltage between the resistor 19 and this resistor is selected so that it reaches the breakdown voltage of the diac 21 when the discharge lamp 5 is not ignited, but does not reach the breakdown voltage when the discharge lamp 5 is operating voltage. The starting device of this device also becomes inoperative when the discharge lamp 5 is ignited.

However, a drawback of this method is that the above-mentioned starting device does not stop when the discharge lamp 5 goes out of action for some reason.

FIG. 6 shows a modification similar to the device of FIG.

Also in this example, corresponding elements are indicated by the same reference numerals.

The difference with the device of FIG. 5 is that in FIG. 6 a resistor 31 with a positive temperature coefficient is used.

This resistor is connected in series with the capacitor 20.

The capacitor 20 is shunted with a conventional resistor 32.

The operation of the circuit of FIG. 6 is substantially the same as the device of FIG.

In the case of FIG. 6, resistor 31 initially has a very low value until the voltage across capacitor 20 reaches the limit voltage of diac 21. In the case of FIG.

However, when the current flows through the resistor 31 for a while, its resistance increases significantly and a considerable voltage develops across this resistor, so that the voltage across the capacitor 20 can no longer reach the threshold voltage of the diac 21. .

In this case too, the starter is stopped.

In the modification shown in FIG. 6, the starting device stops both when the discharge lamp 5 is ignited and when the discharge lamp 5 goes out of ignition for some reason.

When using the devices shown in FIGS. 5 and 6, it is necessary to pay attention to the temperature conditions of the illumination device in which these starting devices are housed.

This is because the ambient temperature as well as the temperature within the lighting device naturally influences the resistance value of the associated resistor, which has a large temperature coefficient.

FIG. 7 shows a modification of FIG. 1.

However, the position of the transistor 35, the point where the diode 36 is inserted, the diode 40, the resistor 39, and the capacitor 3
The point where the control circuit of the transistor 35 consisting of 7 is connected,
The difference is that the capacitor 37 is shunted by a resistor 38.

As shown in FIG. 7, the terminal connected to the diode 40 of this control circuit is connected to the connection point between the connection terminal 1 and the stabilizing inductor 6.

Other elements of the apparatus of FIG. 7 that correspond to those of FIG. 1 are similarly designated by the same reference numerals.

In FIG. 7, as in FIG. 5, a negative temperature coefficient resistor 30 is used to shunt the capacitor 20.

The operation of the circuit of FIG. 7 differs slightly from the circuits of FIGS. 1-6.

In practice, terminals 1 and 2 in FIG.
When connecting to a 50Hz AC voltage source, capacitor 37
Since is not initially charged, the transistor 35 is cut off.

This means that the capacitor 20 cannot be charged.

On the other hand, this means that the direct voltage obtained via the inductor 6 and the diode bridges 9-12 between the conductors 15 and 16 is applied to a voltage divider consisting of the series circuit of resistors 19 and 18.

voltage divider 19.18 together with the threshold of diac 21,
Diac 21 is chosen to break down early in each half cycle of the voltage between terminals 1 and 2.

This means that initially during the half cycle of the voltage between terminals 1 and 2, transistor 17 is almost always conducting.

Therefore, during the first part of the ignition process, the electrodes 3 and 4 of the discharge lamp 5 are preheated almost continuously.

Only when capacitor 37 acquires a predetermined charge through diode 40 and resistor 39 does the base voltage of transistor 35 become high and transistor 35 becomes conductive.

In this case, a situation comparable to that of the starting device in FIG. 1 is obtained.

In this case, capacitor 20 begins to charge through resistor 19, and rapid switching on and off of transistor 17 occurs as in the circuit of FIG.

However, since in the case of FIG. 7 the electrodes 3 and 4 have already undergone a certain preheating, the number of peaks that need to occur between the electrodes 3 and 4 is significantly less than in the case of FIG.

When the discharge lamp 5 is ignited, the starting device stops after a short time due to the action of the resistor 30 with a negative temperature coefficient.

The starting device also stops if the discharge lamp 5 misfires for some reason.

The advantage of the circuit of FIG. 7 is that there is little risk that the discharge lamp 5 will be ignited when the temperature of the electrodes is too low.

This has the advantage of significantly increasing the service life of the discharge lamp 5.

Another advantage is that a limited number of peaks need be generated to ignite the discharge lamp 5.

This means that the time to generate radio interference pulses is extremely short.

In FIG. 8, En indicates the voltage across terminals 1 and 2 as a function of time.

During the time interval designated tl, transistor 35 is non-conducting and electrodes 3 and 4 of FIG. 7 are preheated substantially continuously.

At the end of time t1, transistor 35 is conductive;
Due to transistor 17 and inductor 6, a peak occurs during two half cycles (time interval t2) of the voltage between terminals 1 and 2.

After the time interval t2, the voltage between electrodes 3 and 4 shows a change as shown by the solid line on the right side of FIG.

In fact, immediately after the time interval t2, a small peak occurs between electrodes 3 and 4, as shown in FIG.

However, if the NTC resistor 30 stops the starter, the eighth
The voltage shown at the right end of the figure is obtained.

In one example, capacitor 37 was approximately 22 microfarads.

The resistance value of the resistor 38 was approximately 22 ohms, and the resistance value of the resistor 39 was approximately 330 ohms.

The heating time of electrodes 3 and 4 was adjusted to, for example, 1/2 second.

On each side mentioned above, the starter part can be accommodated in a space of only a few cubic centimeters.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a first example of the device of the present invention, FIG. 2 is a waveform diagram showing the voltage between the electrodes of the discharge lamp as a function of time after switching on the device of FIG. 1, and FIG. Figure 1 is a waveform diagram showing the discharge lamp inter-electrode voltage as a function of time immediately after the discharge lamp is ignited, and Figure 4 is a waveform diagram showing the discharge lamp inter-electrode voltage as a function of time shortly after the discharge lamp in Figure 1 is ignited. 5 is a circuit diagram showing a second example of the device of the present invention, FIG. 6 is a circuit diagram showing a third example of the device of the present invention, and FIG. 7 is a circuit diagram showing a fourth example of the device of the present invention. Circuit-1 FIG. 8 is a waveform diagram showing the discharge lamp inter-electrode voltage of FIG. 7 as a function of time. 1.2...Input terminal, 3,4...Preheating type electrode, 5...Low pressure mercury vapor discharge lamp, 6...Stabilizing inductor, 9-12
...Diode bridge, 17...First (ignition) transistor, 19-21...Control circuit, 19,20...First
Time circuit, 19... Breakdown element, 22... Second (switch off) transistor, 23, 24... Second time circuit, 3
0... Resistor with negative temperature coefficient, 31... Resistor with positive temperature coefficient, 35... (Third) transistor, 19...
First resistor, 20...first capacitor, 18...second resistor.

Claims (1)

[Claims] It comprises two input terminals 1 and 2 which are connected to an alternating current voltage source with a frequency of 1100 Hz or less, both input terminals being used for stabilizing the ignition center of a discharge lamp 5 comprising preheating electrodes 3 and 4. A preheating type electrode which is interconnected by an inductance 6 and the discharge lamp in a series circuit, and whose terminals on the side opposite to the AC voltage source side of the discharge lamp electrode 3.4 are interconnected by a starting device comprising a semiconductor switch 17. In the transformerless ignition power supply device for a discharge lamp, the semiconductor switch is a transistor 17, and a control circuit is connected to the base of the transistor, and the control circuit includes a series circuit of a resistor 19 and a capacitor 20; a charging/discharging circuit 19, 20.21 consisting of a voltage threshold element 21 connected between the common connection point of the resistor and the capacitor and the base of the transistor;
characterized in that the time constant of the resistor-capacitor series circuit is short so that during the ignition process said transistor 17 is made conductive and non-conductive at least several times during each half-cycle of said alternating voltage source. Discharge lamp ignition power supply device.