JPH0151036B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention provides a voltage application period (hereinafter referred to as application period) and a voltage application rest period (hereinafter referred to as rest period).
The present invention relates to a discharge lamp lighting device for lighting a low-pressure discharge lamp such as a fluorescent lamp or a rare gas discharge lamp with a high-frequency alternating current voltage having the following every half cycle.

Previously, Utility Model Publication No. 56-8160 had a distribution period (hereinafter referred to as the application period) as shown in Figure 1 (A).
It is disclosed that the efficiency of the discharge lamp improves when a high-frequency intermittent current having a cutoff period (hereinafter _{referred to as a rest period) T 1 and} a current direction reverses each time is passed through the low-pressure mercury vapor discharge lamp. has been done. This is the application period during which the electrons in the discharge lamp cooled during the rest period T ₀
This is thought to be due to rapid acceleration at T ₁ , and the high-temperature electron density is higher than that during DC lighting or commercial frequency lighting.

Further, in the above-mentioned publication, the circuit shown in FIG. This circuit consists of a bridge circuit in which transistors 5, 6, 7, and 8 are arranged on four sides and a discharge lamp 9 is connected diagonally, another transistor 10 is connected in series on the input side of this bridge circuit, and transistors 5, 6,
The control device 11 controls the opening and closing of the circuits 7, 8, and 10 to obtain a current as shown in FIG. In addition,
1 and 2 are input terminals for connecting a DC power supply.

Furthermore, as disclosed in Japanese Unexamined Patent Publication No. 57-196497 and Japanese Patent Application No. 56-110369, the present inventors light a low-pressure mercury vapor discharge lamp such as a fluorescent lamp with a high-frequency voltage having a rest period T ₀ . As a result of various studies on how to do this, it has become clear that the lamp efficiency can be further improved than the value shown in Japanese Utility Model Publication No. 56-8160.

The lighting circuit shown in the embodiments of JP-A-57-196497 and JP-A-56-110369 uses a separately excited push-pull transistor inverter that generates an output voltage as shown in Figure A, and a capacitive current-limiting impedance. In both the circuit and the circuit shown in Figure B, the voltage applied to the lamp at startup is a rectangular wave voltage with a rest period T ₀ as shown in Figure _A ; A phenomenon was observed in which the starting voltage increased due to the presence of

Therefore, these conventional devices have the disadvantage that the starting voltage must be set sufficiently high, that sufficient consideration must be given to the dielectric strength of the device, and that the loss and capacity of the device must also be increased. Ta.

This invention was made with the aim of improving the above-mentioned drawbacks, and proposes a discharge lamp lighting device with a low starting voltage by providing a starting control means that makes the voltage application period longer when starting a low-pressure discharge lamp than when lighting the lamp. It is something to do.

FIG. 2 is a circuit diagram showing a first embodiment of the present invention, in which 12 is a commercial AC power supply, 13 is a rectifier for full-wave rectification of the power supply 12, 14 is a smoothing capacitor, and 15 is a low-pressure discharge lamp. The high frequency inverter that energizes the fluorescent lamp 16 is a self-excited constant current push-pull transistor inverter in this embodiment.

This inverter 15 is configured as follows. 17 is a high frequency choke coil provided at the input end of the inverter 15; 18 is an output transformer;
8a and 18b are the primary windings, and windings 18a and 1
A high frequency choke coil 17 is connected to the connection point 8b. 18c is a feedback winding, 18s is a secondary winding, 18f and 18f are preheating type electrodes 1 of the lamp 16.
6f and 16f are preheating windings, and 18d is a power supply winding of a control device 19, which will be described later. 20 is a resonant capacitor connected in parallel to the primary windings 18a and 18b; 21a and 21b are transistors, which are a pair of active elements connected between the primary windings 18a and 18b and the negative terminal of the capacitor 14;
a, 22b are a pair of base resistors, 23 is the lamp 1
This is a current limiting impedance for the current of No. 6.

A is a switch device installed in parallel with the lamp 16 at the output end of the inverter 15, with the AC end connected to the lamp 16.
a full-wave rectifier circuit 24 connected in parallel with the transistor 2, and a transistor 2 disposed at the DC end of this rectifier circuit 24.
5.

Note that B is a high frequency power supply device, which includes an inverter 15,
It is composed of a switch device A and a control device 19 including a start control means.

FIG. 3 is a circuit diagram showing one embodiment of the control device 19, in which 18d is a power supply winding provided in the transformer 18, and 26 is a diode bridge for full-wave rectification of the low voltage high frequency wave induced in the winding 18d. , 27 is a smoothing capacitor connected to the output terminal of the diode bridge 26 via a reverse current prevention diode 28, and 29 is a transistor connected in parallel with the capacitor 27 via a resistor 30.
It is placed between the base of the vine and the emitter. Note 3
1 is a constant voltage diode connected to the base of the transistor 29 via a resistor 32. resistance 32
is connected between the output end of diode bridge 26 and diode 28.

Reference numeral C denotes a starting control means, which is composed of a transistor 33 connected in parallel with the transistor 29, and a time limit circuit including a capacitor 34 and a resistor 35 provided at the base of the transistor 33.

In the lighting device configured in this way, when the power source 12 is applied, the rectifier 13 and the capacitor 1
The smoothed DC formed by 4 and 4 is connected to inverter 1
5, the transistors 21a and 21b are alternately opened and closed by the actions of the primary windings 18a and 18b, the resonance capacitor 20, the feedback winding 18c, etc., and the inverter 15 starts self-oscillation. in this case,
Due to the action of the high frequency choke coil 17, the collector currents of the transistors 21a and 21b have a substantially rectangular waveform, and the voltages of the primary windings 18a and 18b have a substantially sinusoidal waveform. Therefore, a substantially sinusoidal high frequency voltage of, for example, 20 kHz as shown in FIG. 4A is generated in the power supply winding 18d. This voltage is full-wave rectified by the diode bridge 26, and the voltage shown in Figure 2 is applied to the constant voltage diode 31, and the capacitor 27 is charged, and the resistor 3
Smoothed direct current is applied to the series circuit of transistor 29 and transistor 29 .

Assuming that the constant voltage diode 31 is cut off at the hatched portion in FIG. 4 and conductive at the blank portion, the transistor 29 is turned on during the period T ₁ and cut off during the period T ₀ as shown in FIG.

However, since the transistor 33 is conductive until the charging current of the capacitor 34 becomes almost zero, the signal shown in FIG.

Therefore, during a predetermined period determined by the capacitor 34 and the resistor 35, the transistor 25 maintains the cut-off state, and a substantially sinusoidal voltage induced in the secondary winding 18s as shown in Figure A is applied to the lamp 16. .

On the other hand, the electrode 16f is preheated by a substantially sinusoidal voltage of the preheating winding 18f, and when its temperature reaches a suitable value, the lamp 16 is started at a relatively low voltage.

After starting, when the charging current of the capacitor 34 becomes close to zero, the transistor 33 is cut off and the transistor 2
A signal as shown in Figure C flows into the base of the inverter 15, and the transistor 25 becomes conductive at the falling part _T01 and the rising part _T02 of the sinusoidal output voltage of the inverter 15 shown in Figure D, and the transistor 25 becomes conductive during the rest period. T ₀ is formed, and near the maximum instantaneous value of the output voltage, the transistor 25 is cut off to form an application period T ₁ . This application period T ₁ is naturally shorter than the sinusoidal voltage applied to the lamp 16 at the time of starting. In this case, unlike the conventional device, a current is supplied to the lamp 16 during the application period T ₁ , and a short circuit current also flows during the rest period T ₀ . Both the voltage and current of the lamp 16 can have beautiful waveforms with steep rises and falls, and the efficiency of the lamp 16 is greatly improved.

High frequency power supply B with low starting voltage as mentioned above
It goes without saying that the loss and capacitance can be small, and the dielectric strength can be relatively simple. However, the above-mentioned embodiment has various advantages as follows.

First, the one shown in Figure 1, Figure 4, is
High output voltage as shown in the right half of Figure 2
The output voltage _of the inverter ₁₅ is
The one in which V _S is almost sinusoidal and the rest period T ₀ is formed at the rising edge of the small instantaneous value has an even smaller capacity, and has the advantage of being able to supply the same amount of power to the lamp 16 as the one in Figure B. be.

Furthermore, in contrast to the conventional device in which the output voltage, output current, and voltages and currents of transistors 5, 6, 7, 8, etc. all have a rectangular waveform, in this embodiment, the collector current of transistors 21a and 21b Since all of the above-mentioned quantities other than 1 are sinusoidal, there is an advantage that radio noise is low.

Furthermore, in the conventional device, transistors 5, 6, 7, 8
The inverter 16, etc. performs steep switching at a high voltage V _A as in this embodiment.
If at least one of the voltage and current is sinusoidal, as in the active elements of the transistors 21a and 21b, the switching loss is theoretically zero, which has the advantage of improving the efficiency of the device. .

Furthermore, when the starting voltage decreases further, transistor 2
As transistor 5, a transistor having a lower breakdown voltage than transistor 10 can be used, and its loss is also reduced, which has the advantage of further improving the efficiency of the device.

The above is an effect of the embodiment. When the lamp 16 is started, if the application period T ₁ is made longer than when it is lit, the starting voltage decreases, and the high-frequency power supply B is required to supply the same amount of power to the lamp 16. The effect of requiring only small loss and capacitance and requiring relatively simple dielectric strength can be achieved by this invention, such as the one shown in Figure 1 (b) and the embodiment shown in JP-A-57-196497. This effect can also be obtained by applying .

FIG. 5 is a circuit diagram of a control device 19 showing a second embodiment of the present invention, in which the same reference numerals as in FIG. shall be exactly the same as.

In the figure, 36 is a comparator IC, which receives the full-wave pulsating voltage V _I that has been full-wave rectified by the diode bridge 26 and the X formed by resistors 37, 38, and 39.
A rectangular waveform base current is supplied to the transistor 25 through the resistor 40 during a period when V _I <V _N , and the base current supply is stopped during a period when _{V I >} V _N. do.

In the configuration as described above, when 12 is turned on, a nearly sinusoidal edge pressure is generated in each winding of the transformer 18 as in the first embodiment, and the transistor 33 becomes conductive, as shown in FIG. As shown in A, the reference voltage V _N is set to a relatively low value V _NS .

Similarly to the first embodiment, after a predetermined time, the transistor 33
When the voltage is cut off, current flows through the resistor 39, and the reference voltage _VN is set to a value _VNS higher than _VNS , as shown in FIG. That is, when the lamp 16 is turned on, the lamp 16 is turned on with an application period T _1B that stably lights the lamp 16 and maximizes the lamp efficiency, and when starting, the lamp 16 is turned on with an application period T _1S that is longer than the period T _1B .
Start 6. Even with such a device, the lamp 16 can be started with a lower voltage than the conventional device, and the same effect as described above can be obtained.

FIG. 7 is a circuit diagram of a control device 19 showing a third embodiment. In the figure, the same reference numerals as in the previous figure indicate the same or corresponding parts, and other parts except for the control device 19 are the same as those shown in FIG. It shall be exactly the same.

In the figure, C is a starting control means which is constructed as follows. 41 is a transistor connected in parallel with the capacitor 27 via a resistor 42; 43 is a contact of a first delay relay; its movable contact 43a is connected to the collector of the transistor 29; and its normally closed contact 43b is connected to the base of the transistor 41. It is connected. 44 is a second delay relay whose time limit operation time is shorter than that of the first delay relay, and its movable contact 4
4a is connected to the base of the transistor 25, and a normally closed fixed contact 44b is connected to the collector of the transistor 41.

Note that the normally open fixed contact 43 of the relay contacts 43 and 44
c and 44c are connected to each other.

In such a configuration, when the power supply 12 is turned on, the transistor 2 is turned on, similar to the one in FIG.
Reference numeral 9 generates a signal as shown in FIG. Therefore, the transistor 41 generates a signal that is an inversion of the signal shown in FIG. As a result, the transistor 25 is cut off at its hatched part as shown in Figure 8A, and conductive at its blank part, so that the voltage that is applied and at rest is reversed from that shown in Figure 4D. 16. During this time, the electrode 16f is preheated by the preheating winding 18f, but the lamp 16 does not start because the voltage application period is short and its instantaneous value is low. After preheating for the predetermined time _T1 in this way, the second relay operates and the contact 44a switches to the contact 44c, and no signal flows into the base of the transistor 25, so as shown in FIG. As shown in Figure B, the transistor 25 continues to be cut off during the entire cycle, and the sinusoidal output voltage of the inverter 15 is continuously applied to the lamp 16, so that the lamp 16 is started at a relatively low voltage. When the first relay operates after a predetermined time _t2 and the contact 43a switches to the contact 44c, the transistor 2
9 generated as shown in FIG.
As shown in FIG. 8C, it is cut off during period T ₁ and conductive during period T ₀ . Therefore the lamp 16
is turned on at a voltage as shown in Figure 4D.

This embodiment not only provides the above-mentioned effects, but also has the advantage of preventing a reduction in lamp life due to cold start, which occurs when the electrode 16f is insufficiently preheated.

FIG. 9 is a circuit diagram showing a fourth embodiment, in which the same symbols as in the previous figure indicate the same or corresponding parts, but the inverter 15 is not provided with preheating windings 18f, 18f.

In the figure, 45 is a smoothed DC power supply, and A is a switch device provided in parallel with the lamp 16, which in this embodiment is connected to the output end of the inverter 15 via electrodes 16f, 16f. Reference numeral 46 denotes a current transformer installed across the electric path _f1 that enters the electrode 16f from the inverter 15 side and the electric path _f2 that exits from the electrode 16 to the switch device A side.
It is connected to a control device 19 whose power source is .

FIG. 10 shows a control device 19 including a starting control means C.
In the circuit diagram, the same symbols as in the previous figure indicate the same or corresponding parts.

In the figure, 47 is a transistor connected in parallel with the smoothing capacitor 27 via a resistor 48;
A transistor 49 is arranged in parallel with the transistor 29, and its base is connected to the collector of the transistor 47. 50 is a diode bridge for full wave rectification of the output of the current transformer 46, 51 is a smoothing capacitor, 52 is a base resistor of transistor 47, 53 is a diode provided between the collector of transistor 29 and the base of transistor 25, 54 and 55 is a capacitor and a resistor connected in series between the negative electrode of the diode 28 and the base of the transistor 25, and the starting control device C is configured as described above.

In such a configuration, when the power source 45 is turned on, a charging current of the capacitor 54 flows through the resistor 55, and the transistor 25 becomes conductive. Therefore, a substantially continuous sinusoidal preheating current flows through the electrodes 16f and 16f, but the same current with opposite directions flows through the electric circuits _f1 and _f2 , and the current transformer 4
6, no signal is generated. As a result, transistor 47 is cut off, transistor 49 is turned on, and the signal generated in transistor 29 is transferred to transistor 4.
It flows to 9th. In this case, the diode 53 prevents the charging current of the capacitor 54 from flowing into the transistors 29 and 49.

Note that during the preheating period, the lamp 16 has electrodes 16f,
Since only a voltage drop of 16f is applied, lamp 1
6 will not start. When the charging current becomes approximately zero after a predetermined period of time, the transistor 25 is cut off and the output voltage of the inverter 15 is continuously applied to the lamp 16 to start the lamp 16 at a low voltage without a cold start. During this period, the diode 53 acts as a level shifting diode, and there is no concern that the signal generated by the transistor 29 will flow into the base of the transistor 25.

Immediately after the lamp 16 starts as described above, a signal is generated in the current transformer 46 and base current flows through the transistor 47.
7 becomes conductive, the transistor 49 is cut off, and the signal generated in the transistor 29 as shown in Figure 4C is input to the transistor 25, and as shown in Figure 4D, the lamp 16 is turned on during the period _T1. A current flows through the switch device A through the electrode 16f during periods T ₀₁ and T ₀₂ . That is, in this embodiment, the same effects as in the third embodiment can be obtained without providing the preheating winding 18f. Note that this control device 19 can also be used in a configuration as shown in FIG.

In the first to third embodiments, for simplicity, the transition from the application period at the time of starting to the application period _T1 at the time of lighting was carried out for a limited time, but in order to ensure the lamp 16 starts, It is necessary to maintain the application period at the time of starting for a while after that, and there is a drawback that overcurrent flows through the lamp 16 and other parts during that time, but this changes as the lamp 16 starts, as in the fourth embodiment. The above disadvantages can be overcome by performing the above transition in response to physical quantities.

In each of the above embodiments, the switch device A is the lamp 16.
Although the capacitor is provided in parallel with the current limiting impedance 23, even if it is provided in series, an application period _T1 with a steep rise can be obtained by using a capacitor as the current limiting impedance 23. In this case, it is necessary to use the inverted signal of each of the above embodiments as the control signal for the transistor 25, but the starting control means C
The same one as in each of the above embodiments can be used.

Furthermore, in each of the above embodiments, the input to the inverter 15 was a smoothed direct current, but the input to the inverter 15 is a pulsating voltage obtained by full-wave rectification of the power source 12, or an auxiliary power source for replenishing the voltage near zero voltage of the pulsating voltage. Application of this invention is particularly effective. This is because using the above voltage has the advantage that the power factor of the device becomes high, but at the time of starting the lamp 16
This is because the lamp 16 has a disadvantage in that the voltage applied to the lamp must be very high, but by applying the present invention, the lamp 16 can be started without having to set the voltage very high.

Although the frequency of the inverter 15 was not particularly mentioned in the above description, as disclosed in detail in Japanese Patent Application No. 110369/1980, the improvement in lamp efficiency obtained by providing the rest period _T0 is approximately 1 kHz per kHz. It was observed that even at 80kHz, a considerable efficiency improvement was obtained. However, from the viewpoint of preventing unpleasant audible noise, the frequency is preferably about 17 kHz or higher, and when a bipolar transistor is used as the transistor 25, the frequency is preferably 100 kHz or lower in order to reduce switching loss.

In all of the above embodiments, only one lamp 16 was used, but the same effect can be obtained by using, for example, two or more lamps 16 connected in series.

Furthermore, in each of the above embodiments, all the low-pressure discharge lamps were fluorescent lamps 16, but improvements in lamp efficiency by providing a rest period T ₀ were also found in rare gas discharge lamps such as neon lamps 16 and krypton lamps 16. Therefore, the present invention can also be applied to those low pressure discharge lamps 16.

As explained above, the present invention provides a high-frequency power supply device for lighting a low-pressure discharge lamp with a high-frequency AC voltage having a voltage application period with a steep rise and a voltage application pause period every half cycle, and By providing a starting control means that makes the voltage application period longer than when the device is lit, it is possible to lower the starting voltage, reduce the loss and capacity of the device, and simplify the dielectric strength of the device. It will be done.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram and circuit diagram of a conventional device, Fig. 2 is a circuit diagram showing a first embodiment of the present invention, Fig. 3 is a circuit diagram of its main parts, Fig. 4 is an explanatory diagram thereof, and Fig. 5 The figure is a circuit diagram of the second embodiment, FIG. 6 is an explanatory diagram thereof,
FIG. 7 is a circuit diagram of the third embodiment, FIG. 8 is an explanatory diagram thereof, FIG. 9 is a circuit diagram of the fourth embodiment, and FIG. 10 is a circuit diagram of the main part thereof. In the figure, 15 is a high frequency inverter, 16 is a low pressure discharge lamp, 16f is an electrode, 19 is a control device, and 21
a and 21b are active elements, A is a switch device, B is a high frequency power supply device, and C is a starting control device. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A high-frequency power supply device for lighting a low-pressure discharge lamp with a high-frequency AC voltage having a voltage application period with a steep rise and a voltage application pause period every half cycle, and when starting the low-pressure discharge lamp, A discharge lamp lighting device comprising a start control means for making the voltage application period longer than when the discharge lamp is lit. 2. In low-pressure discharge lamps that require preheating of the electrodes at the time of starting, a voltage for a short voltage application period is applied to the low-pressure discharge lamp at the beginning of startup, and the electrodes are preheated, and then the voltage application period is increased. 2. The discharge lamp lighting device according to claim 1, wherein the starting control means is configured to start the low-pressure discharge lamp. 3. A high-frequency power supply device includes a high-frequency inverter having a characteristic that output voltage is approximately sinusoidal, and a switch device provided at the output end of the high-frequency inverter, and when lighting a low-pressure discharge lamp, the rising edge of the output voltage is Claim 1 or 2, characterized in that the switch device is controlled so as to form a voltage application suspension period at a value near the maximum instantaneous value of the output voltage and to form a voltage application period near the maximum instantaneous value of the output voltage. discharge lamp lighting device. 4. The discharge lamp lighting device according to claim 3, wherein the switch device is provided in parallel with the low-pressure discharge lamp. 5. The discharge lamp lighting device according to claim 4, wherein the switch device is connected to the output end of a high frequency inverter via the electrodes of the low pressure discharge lamp. 6. The discharge lamp lighting device according to claim 3, wherein at least one of the voltage and current of the active element of the high frequency inverter has a substantially sinusoidal waveform. 7 The starting control means is configured to quickly respond to changes in physical quantities accompanying the starting of the low-pressure discharge lamp in order to shift the voltage application period at the time of starting to the voltage application period at the time of lighting. A discharge lamp lighting device according to any one of items 1 to 6.