JPH10312890A - Electronic discharge tube lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lenghthen the service life by improving utilization efficiency of hot cathode type discharge tubes, and improve reliability by reducing energy consumption by preventing the occurrence of a hindrance to lighting of residual hot cathode type discharge tubes even if either one or more of hot cathode type discharge tubes connected in parallel by two or more are removed. SOLUTION: In the initial stage of closing a power source, operating voltage of an operating signal circuit part 3 of a self-exciting inverter part is supplied in low voltage by operation of a booster circuit part 2 to preheat filaments of discharge tubes. The operating voltage is gradually increased in a prescribed period, and the operating voltage of the operating signal circuit part 3 of the self-exciting inverter part is supplied in a constant value by the booster circuit part 2. Therefore, even if an input power source changes within ± 20%, a discharge tube output change can be stabilized within ± 3%. The filaments of the discharge tubes alternately emit themoelectrons by passing through a discharge passage by the action of a circuit of only a discharge passage dispersing diode existing in a lighting circuit part 4, and utilization efficiency of the filaments can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to maximize the efficiency of use of a discharge tube by turning on a discharge tube by changing a normal power supply to a high frequency and dispersing a discharge path of a filament in order to light the discharge tube. The present invention relates to a lighting device for an electronic discharge tube capable of extending its life and greatly saving energy consumption.

[0002]

2. Description of the Related Art A conventional inverter has two switches S.
1 and S2 and two power supplies E1 and E2 as shown in FIG.
An L / C series circuit composed of a reactor L1 and a capacitor C1 is connected between a connection point of the switches and a connection point of the power supply. When S1 of two switches is turned on and S2 is turned off, L, C
The current iL flowing in the series circuit flows in the direction of the arrow in FIG. When S1 of the two switches is turned off and S2 is turned on, the current iL flowing through the L and C series circuits flows in the direction opposite to the direction indicated by the arrow in FIG.

As described above, the two switches S1 and S2 are alternately turned ON and OFF alternately, so that L,
The direction of the current flowing in the C series circuit can be changed continuously, and the speed at which the switch changes is L, the speed T = 1 near the inherent resonance frequency (see the following equation 1) of the C series circuit. If it is turned ON / OFF at / Fo, a voltage expressed by the following equation 2 is generated at both ends of the reactor L1 and the capacitor C1.

[0004]

(Equation 1)

[0005]

(Equation 2)

[0006] A circuit of a discharge tube lighting device using a self-excited inverter electronically reconfigured using this principle is a discharge tube lighting device using the self-excited inverter shown in FIG. The circuit of FIG. 1 includes transistors Q1 and Q2, which are semiconductor elements that can be used for the same purpose as the switches instead of the two switches S1 and S2 from the circuit of FIG. 2, and replaces the two power supplies E1 and E2. The power supply E is supplied from the outside, and capacitors C2 and C3 for storing power are connected to each other so as to play the same role as the power supply E1, thereby forming a circuit equivalent to the circuit of FIG. In order to alternately turn on and off the two transistors Q1 and Q2, an oscillator transformer T1 is inserted between the connection point of the two transistors Q1 and Q2 and the reactor L1, and the secondary side of the oscillator transformer T1 is inserted. Coil with two transistors Q
Separate operation signal circuits were formed by connecting the bases and emitters of 1 and Q2 in opposite directions in the voltage induction direction.

In FIG. 1, when an operation signal is supplied to the transistor Q2, the transistor Q2 is turned on,
The IL current flows in the direction opposite to the arrow. At this time, when the voltage induced on the secondary side of the oscillation transformer T1 turns off the transistor Q1 and completely turns on the transistor Q2, the oscillation transformer T1 is saturated. The induction direction of the voltage of the coil on the secondary side is reversed, and by turning on the transistor Q1 and turning off the transistor Q2, the IL current flows in the direction of the arrow in FIG. When the oscillation transformer T1 is saturated, the direction of induction of the voltage of the coil on the secondary side of the oscillation transformer T1 is reversed, and the transistor Q1 is turned off and the transistor Q2 is turned on. The subsequent operation repeats self-excitingly even without an external signal. At this time, a voltage expressed by the following equation 3 is generated across the capacitor C1.

[0008]

(Equation 3)

In the circuit of FIG. 1, a hot cathode discharge tube is connected to both ends of the capacitor C1, and a voltage generated at both ends of the capacitor C1 is transmitted to the hot cathode discharge tube, and the hot cathode discharge tube is turned on. This is a general type of a hot cathode type discharge tube lighting device using a self-excited inverter conventionally used.

SUMMARY OF THE INVENTION A conventional self-excited inverter
Since the entire current flowing from the L and C series resonance circuit to the capacitor flows through the filaments on both sides of the hot cathode discharge tube, the heating voltage Vf of the filament is controlled by the heating voltage Vf of the filament inside the filament. The resistance is R
When f, the filament heating voltage Vf is changed by the current flowing through the capacitors of the L and C resonance circuits because Vf = Rf × iL, so that the filament voltage cannot be appropriately adjusted, and the filament heating voltage Vf cannot be adjusted properly. Thermoelectrons are emitted through only one or two points, and high heat is generated at the extreme points. Therefore, there is a problem that the life of the filament cannot be shortened and the original performance cannot be utilized.

Further, in the prior art, when the supply voltage changes, the output frequency changes, the change width of the high frequency output increases, the voltage across the capacitor C1 of the L and C resonance circuit changes, and the illuminance of the lamp also changes. Since it is difficult to supply a preheating voltage to the filament at the beginning of lighting and to configure a control circuit for appropriately coping with the terminal phenomenon of the hot cathode discharge tube, it is difficult to use the hot cathode discharge tube. There is a problem that the use efficiency of the lighting device is deteriorated and the reliability of the lighting device cannot be enhanced.

The present invention appropriately solves the above-mentioned problems of the prior art, and can extend the life of the hot cathode discharge tube and improve the reliability of the lighting device. It is intended to provide a device.

[0012]

According to the present invention, immediately after DC power is supplied to the booster circuit, the filament is supplied to the self-excited inverter by supplying an initial voltage as low as not to turn on the hot cathode discharge tube. Preheat, for a predetermined period,
The voltage gradually rises to turn on the hot cathode discharge tube,
An electronic discharge tube lighting device that supplies a constant voltage to the self-excited inverter after a predetermined period has elapsed, and substantially shuts off a circuit when the end of life of the hot cathode discharge tube is reached. . The lighting device for an electronic discharge tube according to the present invention has a built-in overload protection circuit to enhance reliability, and
Two or more hot-cathode discharge tubes are arranged in parallel with a structure in which the thermoelectron discharge paths are alternately heated from four places of the filament of the hot-cathode discharge tube to increase the use efficiency of the filament and the voltage of the filament can be easily adjusted. It is characterized in that it can be connected and used, and even if one or more hot cathode type discharge tubes are removed, it does not hinder the lighting of the remaining hot cathode type discharge tubes. Further, the lighting device for an electronic discharge tube of the present invention supplies an operation voltage to the self-excited inverter at a low voltage in the initial stage of turning on the power to preheat the filament of the discharge tube, and thereafter, the operation voltage supplied to the self-excited inverter for a predetermined period. Gradually, thereby lighting the discharge tube at a low voltage, supplying a constant constant voltage after the lapse of the predetermined period, stabilizing the operation of the self-excited inverter, and operating at the initial stage of turning on the power. Then, an operation signal is supplied to the self-excited inverter, and after the self-excited inverter operates for one cycle, the operation signal circuit section that interrupts the supply of the operation signal, and the operation voltage supplied from the booster circuit is changed to a high frequency. A self-excited inverter that sends it to the lighting circuit and changes the high-frequency output from the inverter into a sine wave to light the discharge tube. Includes a circuit unit, and is characterized in that so as to cause thermionic emission alternately through the discharge path of the filaments is four type state of the discharge tube during lighting of the discharge tube.

According to the present invention, a DC power supply for outputting a DC power obtained by rectifying an AC input voltage, a booster circuit for converting the DC power supplied from the DC power to a predetermined operating voltage, A self-excited inverter for converting the operating voltage supplied from the booster circuit to a predetermined high frequency, and a lighting circuit for converting the high-frequency output from the self-excited inverter to a sine wave and lighting the discharge tube. It is characterized by. Also, in the present invention, a DC power supply unit for outputting a DC power supply obtained by rectifying an AC input voltage, a booster circuit unit for converting a DC power supply supplied from the DC power supply unit to a predetermined operating voltage, and a booster circuit A self-excited inverter unit that converts the operating voltage supplied from the unit into a predetermined high frequency, a lighting circuit unit that converts the high-frequency output from the self-excited inverter into a sine wave and lights the discharge tube, and a lighting circuit unit. An overload protection circuit for stopping the operation of the self-excited inverter circuit when a load occurs. In the present invention,
The booster circuit unit includes a sensing unit that senses a change in the DC power supply that changes in proportion to the change in the AC input voltage, and an operating voltage that is supplied to a self-excited inverter based on an output from the sensing unit. And an adjusting means (control means) for adjusting the constant voltage to a constant voltage. In the present invention, the booster circuit unit is connected to the DC power supply unit, accumulates a voltage from the DC power supply unit, and releases the accumulated voltage, and is connected to the reactor, and connected to the reactor. A transistor for controlling the accumulation of the voltage or the release of the voltage from the reactor. Further, in the present invention, the lighting circuit section is characterized in that the filament of the hot cathode discharge tube discharges thermoelectrons alternately through four types of thermoelectron discharge paths. And Further, in the present invention, the lighting circuit unit can be used by connecting two or more of the lighting circuit units in parallel and connecting the hot cathode discharge tube to each lighting circuit unit. The lighting circuit section has an infinite impedance when the connected hot cathode discharge tubes are removed,
Since the lighting circuit section from which the hot cathode discharge tube is removed is substantially the same as that separated from the circuit, any one of the plurality of hot cathode discharge tubes connected in parallel is used. Even if more than one hot cathode discharge tubes are removed, there is no problem in lighting the remaining hot cathode discharge tubes.

[0014]

According to the present invention, in the initial stage of power-on, the operation voltage of the self-excited inverter is supplied at a low voltage by the operation of the booster circuit for supplying the operating power to the self-excited inverter, thereby preheating the filament of the discharge tube. Until a predetermined period elapses, the operating voltage of the self-excited inverter is gradually increased to light the discharge tube at a low voltage. After a lapse of a predetermined period, a constant voltage is supplied to the self-excited inverter to stabilize the operation of the self-excited inverter.

Further, in the present invention, the operation signal circuit section operates at an early stage of power-on, supplies an operation signal to the self-excited inverter, and supplies the operation signal after the self-excited inverter operates for one cycle. Interrupt. The self-excited inverter unit converts the operating voltage supplied from the booster circuit to a high frequency and sends it to the lighting circuit unit. The lighting circuit unit converts the high-frequency output of the self-excited inverter into a sine wave to light the discharge tube. At this time, the filaments of the discharge tube alternately emit thermionic electrons through four types of discharge paths.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 3 is a circuit diagram showing a discharge tube lighting device.
In FIG. 3, AC indicates a common AC power supply, and SO indicates a switch. In FIG. 3, LINE FIL
The block described as TER (line filter) is a filter for removing power supply noise, BDI is a rectifying bridging diode, and C1 is a capacitor for waveform shaping. The above components and the like constitute a DC power supply unit 1.

Next, in FIG. 3, a block described as IC1 is an integrated circuit. In FIG. 3, R
9, R10, R11 and R12 are operating voltage detecting sensor resistors, C7 is a charging time constant capacitor, R8 is a signal amplifying resistor, C4 is a high frequency bypass capacitor,
TL1 is a reactor, Q1 is a field effect transistor,
R4 is a gate resistor, R6 is a current detection resistor, R5 is a signal reduction resistor, C5 is a high frequency bypass capacitor, R
2 is a resistor for initial power supply, C3 is a capacitor for smoothing,
R1 and R7 are operating reference voltage supply resistors, C2 is a high frequency signal bypass capacitor, D1 is a rectifying diode,
R3 is a signal supply resistor, D2 is a high frequency rectifier diode, and C6 is a smoothing capacitor. The above components and the like constitute a booster circuit unit 2.

Next, in FIG. 3, Q3 and Q4 are high frequency output transistors, C16 and C17 are power storage capacitors, D7 and D10 are transistor protection diodes, R18 and R19 are base resistors, and D6 and D9 are speed-up diodes. , TL2-F are primary coils of a transformer for detecting a resonance current, TL2-S1 and TL2-S
2 is a secondary coil of the transformer for detecting the resonance current, TL
Reference numeral 3 denotes a resonance rectifier. A self-excited inverter section INV indicated by reference numeral 3 is configured by the above components and the like.

Next, in FIG. 3, C13 and C15 are filament heating voltage adjusting capacitors, C14 is a resonance capacitor, D13, D14, D15 and D16 are filament thermal electron discharge path dispersion diodes, and LA is a hot cathode type discharge. Tube. The lighting circuit section EL indicated by reference numeral 4 is configured by the above components and the like.

Next, in FIG. 3, Q2 is an operation signal transistor, R14 is a base resistor, R13 and R17.
Is a resistor for charging time constant, C10 is a capacitor for charging time constant, D4 is a diode for preventing recharging, and D12 is a diode for preventing reverse voltage. Reference numeral 5 is used for each of the above components.
The operation signal circuit portion TRG indicated by the symbol is configured.

Next, in FIG. 3, TR2-S3 is a secondary coil of the transformer TL2-F for detecting a resonance current, D3 and D11 are high-frequency rectifying diodes, SCR
1 is a thyristor, R16 is a gate resistor, C9 is a gate capacitor, DIAC1 (diarc 1) is a diode AC switch, R20 and R15 are sensor resistors for voltage detection, C8 is a capacitor for a time constant, and TL3-S is the secondary of the reactor TL3. The side coil, D21, is a diode for shutting off the operating power of the IC1. With the above parts,
An overload protection circuit PRO indicated by reference numeral 6 is configured.

Next, the operation of each circuit section configured as described above will be described for each configuration. First, in the DC power supply unit 1, when the switch SO is turned on, the common AC power supply AC is supplied to the input side of the rich diode BDI through a line filter, and the DC power supply unit 1 is connected to both ends of the output side of the bridge diode BDI. Is obtained. This DC power supply ES
It is supplied to the booster circuit section 2. Then, in the booster circuit section 2, a voltage is supplied to both ends of the drain and the source of the field effect transistor Q1 through the reactor TL1, and at the same time, the operation reference voltage V1 (M1) by the resistors R1 and R7 is stored in the storage circuit IC1. Pin
At the same time, the capacitor C3 starts charging with the time constant of the resistor R2 and the capacitor C3 connected to the eighth pin of the storage circuit IC1. Also, at the same time,
By the resistors R10, R11, R12, and C7, the set voltage determined by the following equation 4 passes through R9, and is set to 1 of the integrated circuit IC1.
The pin No. is supplied as a set voltage VI signal, but in the initial stage of turning on the power, the capacitor C7 is charged with the time constant of the capacitor C7 and the resistor R11. Therefore, the set voltage VI is set to the set voltage VI = R12 / ( It gradually decreases from R10 + R12) to R12 / (R10 + R11 + R12). The integrated circuit IC1 is an IC for P, F, C (power, factor, collection), and its internal block diagram is shown in FIG. 8, and its characteristic data is shown in Table 1 below.

[0023]

(Equation 4)

[0024]

[Table 1]

Further, in the booster circuit section 2, when the capacitor C3 connected to the 8th pin of the integrated circuit IC1 is charged and charged to the operating voltage VCC of the integrated circuit IC1, the internal circuit of the integrated circuit ICI operates. become,
A pulse output signal is output to the seventh pin of the buyout (VOUT). This pulse output signal is supplied to the gate of the field effect transistor Q1 through the resistor R4. The field effect transistor Q1 turns on when a gate pulse signal is input, and turns off after energy is stored in the reactor TL1. When the field effect transistor Q1 is turned off, the energy stored in the reactor TL1 is rectified through the diode D2 and the capacitor C
6, the DC voltage VS is supplied to the self-excited inverter unit 3, energy is accumulated in the reactor TL2, and a voltage is induced across the secondary coil of the reactor TL2 to be discharged. This induced voltage is
1 and smoothed by the capacitor C3, supplied to the operating voltage VCC of the storage circuit IC1, and passed through the resistor 3 to the 5th pin of the integrated circuit IC1.
It is supplied as a T signal.

When the field effect transistor Q1 is turned on and a current starts to flow, a voltage is generated across the current sensor resistor R6, and this voltage passes through the resistor R5 and is applied to the fourth pin of the integrated circuit IC1 by the VCSEL. Supplied as a signal.

As described above, when the signal indicated by the characteristic data of the integrated circuit IC1 in Table 1 enters each pin of the IC1,
When the internal circuit of the integrated circuit IC1 operates, the DC power supply E
When the change in S is sensed, the field effect transistor Q1
N, the rate of turning off is adjusted, and the DC voltage VS is controlled so as to always become a constant constant voltage. That is, in this embodiment, the DC power supply ES is obtained by performing full-wave rectification on the AC input voltage, and the DC voltage VS is an operating voltage supplied to the self-excited inverter unit. Sensing the change of the DC power supply ES fluctuating in proportion to the fluctuation of
The N-OFF ratio is adjusted so that the DC voltage VS, which is the operating voltage of the self-excited inverter, is always controlled to be constant.

This voltage is varied by resistors R10, R11 and R12 while being inversely proportional to the set voltage VI of the integrated circuit IC1.

At the initial stage of turning on the DC power supply ES, while the time constant is charged by the capacitor C7 and the resistor R11, the set voltage VI of the integrated circuit IC1 gradually decreases, and the DC voltage VS gradually increases. When the charging of the capacitor C7 is completed, the setting voltage VI = R12 / (R10 +
R11 + R12) is supplied to the self-excited inverter unit 3 as the DC voltage VS.

Next, the operation signal circuit portion T indicated by reference numeral 5
In RG, at the initial stage when the switch SO is turned on, the DC power supply VS is connected to the reactor TL1 and the rectifying diode D1.
2, a resistor R13 for the charging time constant,
The capacitor C10 starts charging with the time constant of R17 and the capacitor C10 for charging time constant, and the capacitor C1
After 0 is charged to the voltage set by the resistors R17 and R13, the integrated circuit IC1 of the booster circuit section 2 operates, and the output signal is supplied to the operation signal transistor Q2 through the base resistor R14. As a result, the operation signal transistor Q2 is turned on, and at the same time, the voltage charged in C10 passes through the collector of the operation signal transistor Q2, passes through the diode D12, and passes through the high-frequency output transistor Q4 of the self-excited inverter unit 3. Of the transistor Q4
N.

In the self-excited inverter section 3, when the high-frequency output transistor Q4 is turned on, the DC power supply ES is supplied, and at the same time, the charged power storage capacitors C16 and C17 are charged. From C17, a filament thermoelectron discharge path dispersion diode D16 and a resonance capacitor C14 of the lighting circuit section EL indicated by reference numeral 4, a filament thermoelectron discharge path dispersion diode D14, and a filament F1 of a hot cathode discharge tube LA. Further, a closed circuit is formed that flows to the collector of Q4 through the primary coil TL2-F of the resonance reactor TL3 and the resonance current detection transformer TL2, and the iL1 current flows.

At this time, the resonance current detecting transistor T
Opposite voltages are induced in the secondary-side coils TL2-S1 and TL2-S2 of L2, and turn on the transistor Q4 completely and turn off the transistor Q3.

When the transistor Q4 is completely turned on, i
When the L1 current sufficiently flows and the resonance reactor TL3 becomes saturated, the current of iL1 gradually decreases.
At this time, the resonance current detecting transformer TL2
The voltage induced in the secondary coils TL2-S1 and TL2-S2 is inverted, and Q4 of the two high-frequency output transistors Q3 and Q4 is turned off and Q3 is turned on. Then, the voltage charged in the power storage capacitor C16 of the lighting circuit unit 4 causes the capacitor C16 to pass through the transistor Q3, and further, the primary coil TL2- of the oscillation current detection transformer.
Current flows in the IL2 direction through F, the reactor TL3, the thermionic discharge path dispersion diode D13, the capacitor C14, the thermionic discharge path dispersion diode D15, and the filament F2 (see FIG. 4). When the iL2 current sufficiently flows, the resonance reactor TL3 further saturates, and the iL2 current gradually decreases. At this time, the resonance current detecting transformer TL
The voltage induced in the secondary coils TL2-S1 and TL2-S2 of the second high-frequency output transistor is further inverted, and Q4 of the two high-frequency output transistors is turned on and Q3 is turned off.
The self-excited inverter unit 3 repeats such an operation in a self-excited manner.

When the high-frequency output transistor Q4 is turned on, the voltage charged in the capacitor C10 from the operation signal circuit portion TRG indicated by reference numeral 5 is discharged through the diode D4. Then, the operation speed of the self-excited inverter becomes relatively much faster than the time constant recharged by the resistors R13 and R17 and the capacitor C10, and the time for discharging through the transistor Q4 becomes shorter than the time for charging. Then, the capacitor C10 cannot be recharged, and after the self-excited inverter unit 3 operates for one cycle, the operation signal circuit unit TRG indicated by reference numeral 5 stops operating.

Next, the detailed operation of the lighting circuit section 4 connected to the high-frequency output terminal of the self-excited inverter section will be described with reference to the circuit diagram of the lighting circuit section in FIG. FIG.
In the above, when the high-frequency output transistor Q3 of the self-excited inverter unit is turned off and the high-frequency output transistor Q4 is turned on, the current of iL1 is stored in the capacitor C17 for storing power, the capacitor C17, the diode D16, and the capacitor C14. , Through the diode D14, the filament F1, and the transformer TL3 to flow through the transistor Q4. Then, both ends of the filament F1 have VFAB =
A voltage is generated by F1 × iL1, and the filament F1 is overheated.

At this time, the voltage VF across the filament F2
From the capacitor C17, the filament F2 can be obtained from the CD.
To the capacitor C through the diode D15.
Although the iL1 current must flow through 14, no current can flow through diode D15 because diode D15 is connected in the opposite direction to this flow of iL1 current. Therefore, since there is no current flowing through the filament F2, the voltage VF across the filament F2
The CD goes to virtually zero.

On the other hand, thermionic emission from the filament of the hot cathode discharge tube LA occurs through the discharge path having the highest potential difference. At this time, the voltage applied between the filament extreme points is as shown in the following equation 5.

[0038]

(Equation 5)

As a result, VC of the capacitor C14 and i
Since there is a 90 ° phase difference between C, iC × VC
> 0 (iC × VC is greater than zero), the maximum potential is V
BC and VBD. At this time, the potential difference between both ends of the VCD is “0”, and thermionic emission is started from the B pole to the filament F.
2 is diffused throughout. Also, iC × VC <0 (i
C × VC is smaller than zero), the maximum potential is VAC and V
AD, and thermionic emission changes from the A pole to the filament F2.
It spreads to the whole.

On the contrary, the output transistor Q3 of the self-excited inverter section 3 is turned on and Q4 is turned off.
At F, the current of iL2 flows to the diode D13, the capacitor C14, the diode D15, and the filament F2 through the transistor Q3 due to the voltage stored in the power storage capacitor C16. Then, VFCD = FCD × i is provided at both ends of the filament F2.
A voltage is generated by L2 to heat the filament F2. At this time, both ends FAB of the filament F1 must flow through the diode D14 from the transformer TL3 via the filament F1 to the capacitor C14, and the diode D14 is connected in the reverse direction to the flow of the iL2 current. IL2
No current can flow through diode D14. Accordingly, since there is no current flowing through the filament F1, the voltage VFAB across the filament F1 becomes substantially zero.

On the other hand, thermionic emission in the filament of the hot cathode discharge tube LA occurs through a discharge path having the highest potential difference. At this time, the voltage applied between the extreme points of each filament is as shown in the following equation 6.

[0042]

(Equation 6)

As a result, there is a phase difference of 90 ° between VC and iC of the capacitor C14, and iC × VC> 0
(IC × VC is greater than zero), the maximum potential is VA
D and VBD, and when iC × VC <0 (iC × VC is smaller than zero), the maximum potentials become VAC and VBC.

By the way, since VAB = 0, thermionic emission actually diffuses from the D pole to F1 while C1
When the phase of 4 is inverted, the C pole spreads to F1. According to Equations 5 and 6, while the self-excited inverter unit 3 operates for one cycle, in the hot cathode discharge tube LA, thermionic emission is F2 from the B pole, F2 from the A pole, and D pole. Thus, there are four types of discharge paths that diffuse from F1 and C to F1.

Accordingly, since the hot cathode discharge tube has such four discharge paths, heat is prevented from being intensively emitted from one pole point where the filament exists. This increases the efficiency of use of the filament and extends its life.

When the hot-cathode discharge tube LA is removed from the lighting circuit section of FIG. 4, an equivalent circuit of FIG. 7A is obtained. That is, the capacitor C13 and the diode D1
A DC voltage is supplied from the series circuit of No. 4 to the capacitor C13 by the diode D14, and the value of the impedance XC increases to "infinity" due to XC = 1 / 2πf, thereby forming an open circuit in which no current flows. Similarly, the series circuit of the capacitor C15 and the diode D15 is an open circuit in which no current flows. Also, from the diagram of FIG.
Diode D13, capacitor C14, diode D
In the circuit of No. 16, diodes D13 and D16 are connected in opposite directions to both ends of the capacitor C14, so that no current flows. When the hot cathode discharge tube LA is removed from the lighting circuit section of FIG. 4, the lighting circuit becomes an open circuit having an infinite impedance as shown in FIG. 7 (3). Therefore, as shown in FIG. 6, when two or more lighting circuit units are connected in parallel and used, even if one of the hot cathode type discharge tubes connected to each lighting circuit unit is removed, other lighting circuit units are removed. The effect is obtained that the lighting circuit section is not hindered at all. Note that the lighting circuit unit 4 of the present embodiment operates equivalently even when connected as shown in FIG. 5, similarly to the lighting circuit unit shown in FIG.

When the self-excited inverter is operating, TL, which is the primary coil of the transformer TL2,
When the normal operating current of the self-excited inverter section flows through 2-F1, a voltage of about 3 V is generated across both ends of the secondary coils TL2-S1 and TL2-S2 of the transformer TL2, and the two transistors Q3 And supply a voltage to the base of Q4. A voltage of about 20 V is generated at both ends of TL2-S3, and a thyristor S is connected through a diode D3.
It is supplied to CR1.

On the other hand, the thyristor SCR1 has a higher resistance value at both ends of the anode and the cathode and is electrically OF
When the trigger (TRIGGER) signal enters the gate (GATE) while maintaining the F state, the gate (GATE) is turned on and the resistance at both ends of the anode and the cathode is reduced, which is the same as when the switch is turned on. And the voltage between both ends of the cathode is close to zero, and once turned ON, the ON state is continuously maintained until the voltage is cut off.
C. R (silicon, control, rectifier SILICON, CONTROL RECTIFIF
ER).

Next, the operation of the overload protection circuit 6 of FIG. 3 will be described. When an overcurrent flows in the lighting circuit unit 4 due to the end of the life of the hot cathode discharge tube or an erroneous connection or the like, the overcurrent is guided to the secondary coil TL3-S of the reactor TL3 in the self-excited inverter unit 3. Voltage rises in the same way. When this voltage rises, the voltage rectified by the rectifying diode D11 and charged in the capacitor C8 by the resistors R20 and R15 similarly rises. The voltage of the capacitor C8 is a diarc (DIAC)
When the trigger voltage rises to 1, the trigger 1 triggers and a trigger signal is supplied to the gate of the thyristor SCR1 to turn on the thyristor SCR1. When the thyristor SCR1 turns on, the transformer TL
The voltage of TL2-S3, which is a secondary coil of the thyristor SCR1, is the internal voltage of the diode D3 and thyristor SCR1.
２2V, and the voltage across TL2-S1 and TL2-S2 also decreases at the same rate as TL2-S3.
It falls to 1 to 0.3V. As a result, the base (BASE) voltages of the two high-frequency output transistors Q3 and Q4 supplied by TL2-S1 and TL2-S2 fall below the operating point, and the high-frequency output transistors Q3 and Q4
Stops working. At the same time, the capacitor C10 is discharged through the series circuit of the diode D1 and the thyristor SCR1 so as not to be recharged, and the operation of the operation signal circuit unit 5 is interrupted. At the same time, the smoothing capacitor C3 in the booster circuit is also discharged through the series circuit of the diode D21 and the thyristor SCR1, and the operation of the booster circuit is also interrupted, so that the operation of the entire circuit is interrupted and the circuit is protected.

FIG. 9 is a schematic block diagram showing an electronic discharge tube lighting device according to another embodiment of the present invention. FIG.
, Reference numeral 11 denotes a noise filter, 2 denotes a constant voltage and T. H. D. (Total Harmonic Di
a control circuit, 13 a control circuit, 14 an inverter circuit, 15 an operation signal supply circuit,
16 and 17 are lighting circuits, 18 and 19 are lamps, 20
Is an overload protection circuit. Next, the operation of the apparatus shown in FIG. 9 will be described. The noise filter 11 rectifies an AC voltage from the AC power supply to convert the DC power supply to a constant voltage and a T.V. H. D control circuit 1
2 and the control circuit 13. Constant voltage and T. H. When the DC power is supplied from the noise filter 11, the D control circuit 12 supplies an operating voltage at a low voltage to the inverter circuit 14 at the initial stage of turning on the power to preheat the filament of the discharge tube, and thereafter for a predetermined period. Then, the operating voltage supplied to the self-excited inverter is gradually increased, so that the discharge tube is lit at a low voltage. After the predetermined period has elapsed, a constant voltage is supplied to stably operate the inverter circuit 14. Make it work. Operation signal supply circuit 15
Operates at an early stage of power-on, supplies an operation signal to the inverter circuit 14, and stops the supply of the operation signal after the inverter circuit 14 operates for one cycle. The inverter circuit 14 has a constant voltage and T.V. H. By changing the operating voltage supplied from the D control circuit 12 to a high frequency, the lighting circuit 16,
Send to 17. The lighting circuits 16 and 17 convert the high-frequency output from the inverter circuit 14 into a sine wave, and
19 is turned on. When an overcurrent flows through the lighting circuit unit 4 due to the end of life of the hot-cathode type discharge tube or misconnection, etc.,
The overload protection circuit 20 outputs a signal to the operation signal supply circuit 15 to stop the operation of the inverter circuit 14. In this case, the overload protection circuit 20 also outputs a signal to the control circuit 13 so that the constant voltage and the T.V. H. The operation of the D control circuit 12 is stopped.

[0051]

According to the present invention, in the initial stage of turning on the power, the operation voltage of the self-excited inverter is supplied at a low voltage by the operation of the booster circuit for supplying the operating power to the self-excited inverter, thereby preheating the filament of the discharge tube. Then, by gradually increasing the operating voltage of the self-excited inverter during a predetermined period, the discharge tube is turned on at a low voltage, and the life of the discharge tube is extended. Supply the operating voltage to the inverter at a constant constant voltage, stabilize the operation of the self-excited inverter, and when the input power changes within ± 20% due to fluctuations in the normal power supply, etc., change the output change width of the discharge tube to ± 20%. Since the flow of voltage and current inside the discharge tube is stabilized by stabilizing it within 3%, it is possible to extend the life and maintain a constant illuminance at all times.

Further, it is possible to solve the problem that the thermoelectrons are intensively emitted from a specific position of the filament as in the conventional lighting device for a discharge tube, and the temperature at that position is significantly increased, thereby shortening the life of the discharge tube. In order to achieve this, the filament of the discharge tube alternately heats through at least four types of discharge paths by the action of a circuit which is simply composed of at least four discharge path dispersing diodes in the lighting circuit section. Electron emission is caused to increase the use efficiency of the filament.

At this time, since the transition of the thermionic discharge path changes linearly, there is no generation of noise, and the filament heating voltage can be easily set only by the two filament heating voltage adjusting capacitors. It is possible to improve the use efficiency of the tube and prolong the life of the discharge tube, thereby maximizing energy saving.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a lighting device for a discharge tube using a self-excited inverter according to one embodiment of the present invention.

FIG. 2 is a circuit diagram showing a conventional inverter.

FIG. 3 is a circuit diagram showing a discharge tube lighting device according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating a lighting circuit unit according to the embodiment.

5 is a diagram illustrating a circuit that operates equivalently to the lighting circuit unit of FIG. 4;

6 is a diagram showing an example in which two or more lighting circuit units of FIG. 4 are connected in parallel.

FIG. 7 is a circuit diagram for explaining an operation of the lighting circuit of FIG. 4;

FIG. 8 is a diagram showing a block diagram (BLOCK DIAGRAM) of the integrated circuit IC1 of FIG. 3;

FIG. 9 is a schematic block diagram showing an electronic discharge tube lighting device according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 DC power supply unit 2 Booster circuit unit 3 Self-excited inverter operation signal circuit unit 4 Lighting circuit unit 5 Operation signal circuit unit 6 Overload protection circuit unit 11 Noise filter 12 Constant voltage and T.V. H. D control circuit 13 control circuit 14 inverter circuit 15 operation signal supply circuit 16, 17 lighting circuit 18, 19 lamp 20 overload protection circuit

Claims (7)

[Claims] 1. A DC power supply unit for supplying DC power to a booster circuit unit to operate the booster circuit unit, rectifying an output from the booster circuit unit and receiving a supply as an operation power supply, and receiving an operation signal from the booster circuit unit. Self-excited inverter unit that performs an initial operation upon receipt of the signal, and a self-excited oscillation signal in a circuit connected in series between a connection point of two output transistors of the self-excited inverter unit and a hot cathode discharge tube. A detection transformer, and two secondary coils used for supplying a base voltage to the two output transistors in the three secondary coils of the self-excited oscillation signal detection transformer. When the lighting circuit section is connected to both ends of the other secondary coil other than the side coil and the lighting circuit section at the end of the life of the hot cathode discharge tube is overloaded, the circuit is substantially turned off. An overload protection circuit unit that shuts off the hot cathode discharge tube and the self-excited discharge tube in a circuit that is connected between two power supply capacitors that constitute the self-excited inverter unit together with the two output transistors. From the lighting circuit excluding the excitation oscillation signal detection transformer and the resonance reactor, the filaments of the hot cathode discharge tube discharge thermoelectrons alternately through four types of thermoelectron discharge paths. A lighting circuit configured to easily adjust the heating voltage of the filament of the hot cathode discharge tube; immediately after DC power is supplied to the booster circuit,
To the self-excited inverter unit, an initial voltage is supplied to such an extent that the hot-cathode discharge tube is not turned on, and then the filament is preheated for a predetermined period, and the operating voltage is gradually increased while the hot-cathode discharge is performed. When the operating voltage rises after the predetermined period elapses after the tube is turned on, the self-excited inverter unit has a stable constant voltage (always constant even if there is a change in input voltage or output load). And the filament of the hot cathode discharge tube is heated alternately through four types of thermionic discharge paths. Two or more hot-cathode type discharge tubes can be connected to each lighting circuit unit in parallel and used, and the lighting circuit unit is connected to each of the connected hot-cathode type discharge tubes. Discharge tube When removed, the lamp has an infinite impedance, and since the hot-cathode discharge tube is removed, the lighting circuit section is virtually the same as being separated from the circuit. Any one of the hot cathode discharge tubes connected in parallel as described above
An electronic discharge tube lighting device characterized in that even if more than one hot cathode discharge tube is removed, there is no problem in lighting the remaining hot cathode discharge tubes. 2. A DC power supply for outputting a DC power obtained by rectifying an AC input voltage; a booster circuit for converting the DC power supplied from the DC power to a predetermined operating voltage; A self-excited inverter unit that converts the operating voltage supplied from the unit into a predetermined high frequency, and a lighting circuit unit that converts the high-frequency output from the self-excited inverter into a sine wave to light the discharge tube. Electronic discharge tube lighting device. 3. A DC power supply for outputting a DC power obtained by rectifying an AC input voltage; a booster circuit for converting the DC power supplied from the DC power to a predetermined operating voltage; A self-excited inverter unit that converts the operating voltage supplied from the unit into a predetermined high frequency, a lighting circuit unit that converts the high-frequency output from the self-excited inverter into a sine wave to light the discharge tube, When a load occurs, an overload protection circuit unit that stops the operation of the self-excited inverter circuit unit,
An electronic discharge tube lighting device comprising: 4. The electronic discharge tube lighting device according to claim 2, wherein the booster circuit unit senses a change in the DC power supply that changes in proportion to a change in the AC input voltage. Adjusting means (control means) for adjusting the operating voltage supplied to the self-excited inverter based on the output from the sensing means so that the operating voltage is always constant. Lighting device. 5. The electronic discharge tube lighting device according to claim 3, wherein the booster circuit is connected to the DC power supply, stores a voltage from the DC power supply, and stores the stored voltage. An electronic discharge tube lighting device, comprising: a discharger that emits light; and a transistor that is connected to the discharger and controls accumulation of voltage to the discharger or discharge of voltage from the discharger. 6. The electronic discharge tube lighting device according to claim 3, wherein the lighting circuit section discharges thermoelectrons alternately through four types of thermoelectron discharge paths in a filament of the hot cathode discharge tube. An electronic discharge tube lighting device, characterized in that it is adapted to perform the following operations. 7. The electronic discharge tube lighting device according to claim 3, wherein the lighting circuit section connects two or more of the lighting circuit sections in parallel to each other, and applies the heat to each lighting circuit section. Cathode-type discharge tubes can be connected and used, and the lighting circuit section has an infinite impedance when the respective connected hot-cathode discharge tubes are removed, Since the lighting circuit section from which the hot cathode discharge tube is removed is substantially the same as that separated from the circuit, any one of the plurality of hot cathode discharge tubes connected in parallel is used. An electronic discharge tube lighting device, characterized in that even if at least two hot cathode discharge tubes are removed, there is no problem in lighting the remaining hot cathode discharge tubes.