JPH04298988A - El light emitting power supply circuit and power supply circuit for el - Google Patents

Abstract

PURPOSE:To improve lighting efficiency by providing a bypass channel, having a reverse current bypass diode for bypassing a zero cross switch mechanism, respectively in a pair of positive and negative switches of an inverter. CONSTITUTION:When a positive trigger pulse from a plus pulse selecting circuit 2 is applied to a gate of a TRIAC T1 which is a zero cross switch, T1 in a plus side channel is turned on. When electroluminescence EL is charged to peak voltage, the T1 is turned off. Next, a reverse current is fed back to a plus current side through a reverse current bypass diode D1 of a bypass channel and collected as surplus power. When a trigger inverting pulse comes from a minus pulse select inverting circuit 3, a TRIAC T2 in a minus side channel is turned on and similarly actuated. In this way, EL lighting efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to an EL (electroluminescence) power supply circuit for lighting an EL (electroluminescence) panel and a power supply circuit for EL.

<Prior art> A driving method that uses an inverter circuit to convert DC power to AC power to light an EL panel is used, for example, in the backlight of an LCD panel of a small LCD TV or a laptop computer with a built-in LCD display. widely used.

In the conventional technology used for these, EL to turn on the light
EL light fixtures are manufactured according to the size (area) and lighting brightness, and there is no single light fixture that can accommodate a wide variety of EL areas and lighting brightnesses.

In addition, among these conventional technologies, the most popular L.L.
In inverters (long life inverters), EL C
value (capacitance) and inductor L value (inductance)
A method is used in which the EL panel is turned on by following a resonant frequency determined by the following. When the C value of the EL deteriorates and the brightness of the EL decreases, the resonant frequency increases, and the lighting frequency of the EL increases following the resonant frequency.
A method is used to compensate for the decrease in the luminance of L.

However, this method also has many problems, such as the lighting brightness of the EL being determined automatically by the resonance frequencies of L and C, and it is difficult to manufacture a device that lights a large EL panel. There is.

For example, currently, the size is equivalent to A4 size (400 to 600 cm2).
) is considered to be the maximum area that can be lit in practice.

Furthermore, in order to turn on a large-area EL panel, it is necessary to switch a large current value, which increases power loss due to switching loss, and also causes a serious problem of heat generation due to switching loss. Moreover, as a heat countermeasure, it is necessary to install a heat sink, etc., which results in an increase in the size of the light ignition device.

In addition, EL has a higher lighting efficiency (1
Luminous flux divergence per watt) is extremely poor. For example, incandescent lamps emit approximately 10 lumens of luminous flux per watt, but in the case of EL panels, even green panels, which are said to have the highest lighting efficiency, emit only about 1 lumen at most. There is.

A large part of the cause of this depends on the quantum efficiency of electrons, holes, etc. excited by voltage, but even if the problem of quantum efficiency is set aside as an in-nature physical property problem related to EL itself, it still remains. The problem of dielectric loss in EL panels has been pointed out as a major problem. That is, this problem arises from the fact that a capacitive load characteristic is intentionally given to the EL panel in order to apply an alternating current voltage to the EL.

In this case, the problem of capacitive load characteristics of EL, which becomes a problem when the EL panel is turned on with alternating current, is different from the problem of dielectric loss in a strict sense.

In a strict sense, the dielectric loss of a dielectric is a hysteresis loss per cycle, but the dielectric loss of an EL, which is a problem in conventional technology, is rather a short circuit of charges or a recombination loss of positive and negative charges. It is a phenomenon that can be understood.

<Problems to be Solved by the Invention> A main object of the present invention is to provide an EL light emitting power supply circuit and an EL power supply circuit having high lighting efficiency.

<Means for Solving the Problems> Such objects are achieved by the following inventions (1) to (10).

(1) An EL circuit including an EL or EL string having capacitive load characteristics and an inductor is configured as part of the series coupled component, and one end of this EL circuit is coupled to the coupled output terminal of the inverter, The other end is connected to the intermediate potential terminal or ground terminal of the DC input power supply of the inverter, and each of the pair of positive and negative switches of the inverter is configured using a zero cross switch mechanism that automatically closes the channel when the current value becomes zero. An EL light emitting power supply circuit characterized in that each of the positive and negative switches is provided with a bypass channel having a reverse current bypass diode for bypassing the zero cross switch mechanism.

(2) An EL circuit including an EL or EL string having capacitive load characteristics is configured as part of the series-coupled component, and this EL
The circuit is coupled to the output terminal of the secondary side of the transformer, a bipolar capacitor is coupled in series to the primary side of the transformer to form a primary circuit, and one end of this primary circuit is coupled to the coupled output terminal of the inverter. and the other end is connected to the intermediate potential terminal or ground terminal of the DC input power supply of the inverter, and each of the pair of positive and negative switches of the inverter uses a zero cross switch mechanism that automatically closes the channel when the current value becomes zero. 1. An EL light emitting power supply circuit comprising: a bypass channel having a reverse current bypass diode for bypassing the zero-crossing switch mechanism in each of the positive and negative switches.

(3) The above (2) in which a compensating inductor is inserted in the output terminal of the secondary side of the transformer in series with the EL or EL string.
The EL light emitting power supply circuit described in .

(4) A pair of capacitors with equal capacities are connected in parallel to the other end of the EL circuit, and the other end of the pair of capacitors is cross-linked between the DC input power terminals of the inverter.
).

(5) A pair of capacitors of equal capacity are connected in parallel to the other end of the primary side circuit, and the other end of the pair of capacitors is cross-linked between the DC input power supply terminals of the inverter.
2) or the EL light emitting power supply circuit according to (3).

(6) Due to the combined action of the EL circuit or the primary circuit, the zero-cross switch mechanism of the pair of positive and negative switches of the inverter, and the bypass channel having a reverse bypass diode, the EL, EL string, or bipolar capacitor The EL light emitting power supply circuit according to any one of (1) to (5) above, which collects charges charged up to the same power supply side as a reverse current.

(7) By the action of the inductance of the EL circuit or the primary side circuit, a steep rise in the current value is suppressed when the pair of positive and negative switches of the inverter are opened, and by the action of the zero cross switch mechanism, the switches are closed. The above-mentioned method (1) reduces the switching energy loss accompanying the opening/closing operation of the switch of the inverter by reducing the current value during the switching operation.
1) The EL light emitting power supply circuit according to any one of (6).

(8) The EL light emitting power supply circuit according to any one of (1) to (7) above, wherein the switching frequency of the inverter is set or variably set to set or variably set the lighting brightness of the EL or EL row. .

(9) One or more of the input power supply voltage of the inverter, the winding ratio of the transformer, and the inductance of the compensation inductor are set or variably set, and the EL
Alternatively, the EL light emitting power supply circuit according to any one of (1) to (8) above, which sets or variably sets the lighting brightness of the EL row.

(10) The EL circuit has a coupling terminal to which the EL or EL column can be detachably coupled, and the coupling terminal is connected to the E
An EL lighting circuit according to any one of (1) to (9) above is constructed by combining L or EL columns.
Power supply circuit for L.

<Function> The EL light emitting power supply circuit of the present invention is intended to recover surplus power charged up to the EL panel by a reverse current, and the following four functions are simultaneously achieved in terms of energy efficiency.

(2) Recombining positive and negative charges is prevented by recovering surplus power that is simply stored in the EL panel as a surplus charge without becoming light, as a reverse current, and eliminates or reduces power loss due to charge recombination.

■ Eliminate switching loss through the action of inductance and zero cross switch.

The reverse current recovery mechanism is automatically achieved by the combination of the zero cross switch and the bypass channel using the reverse bypass diode, and the current waveform for each half cycle is automatically locked. Therefore, there is no need to manually set the channel opening (ON) time width according to the area of the EL panel. In other words, in the present invention, in addition to the effects of (1) and (2), the third effect is that (1) the dynamism of the lighting circuit is achieved in such a way that it automatically follows the area of the EL panel; It can accommodate a wide range of different EL areas.

Furthermore, in the EL lighting system according to the present invention, the EL lighting frequency and power supply voltage can be treated as exogenous variables for the dynamism of the LCR circuit in the lighting circuit, or as parameters outside the system. Also L
The basic dynamism of the CR circuit is not affected. In particular, the lighting frequency can be regarded as an extrasystem parameter.

These lighting frequencies and voltages affect the EL lighting brightness, and in the present invention, the EL lighting brightness can be varied by adjusting the frequency and voltage without affecting the basic dynamism of the EL lighting circuit. Can be set. That is, in addition to the effects of (1), (2), and (2) above, the present invention has a fourth effect: (2) By variably adjusting the lighting frequency and voltage, the EL lighting brightness can be adjusted without affecting the dynamism of the circuit. can.

<Example> A specific circuit configuration of the first aspect of the present invention will be described with reference to FIGS. 1 and 2.

In the EL light emitting power supply circuit shown in FIGS. 1 and 2,
Each EL circuit is an LC circuit (strictly speaking, an LCR circuit) in which an EL panel EL and an inductor L are connected in series.

This EL circuit may include an EL panel and an inductor L as at least part of the series-coupled components.

One end of the EL circuit, which is the LC or LCR circuit, is connected to the combined output terminal of the inverter.

Further, the other end of the LC circuit or LCR circuit may be coupled to an intermediate potential terminal or a ground terminal of the DC input power source of the inverter.

In addition, the EL panel EL is composed of EL and EL columns, and the EL panel EL is composed of EL and EL columns.
The L column is usually configured by connecting a plurality of ELs in parallel.

Note that in order to set the C value in the circuit to a predetermined value, a bipolar capacitor may be connected in parallel with EL.

Furthermore, the order in which EL and L are coupled may be either on the inverter side.

The EL light emitting power supply circuit of the present invention is driven at a frequency f, but normally f is about 50Hz to 600Hz, EL capacitance is about 0.1μF to 10μF, and L is about 30mH to
It is about 10H.

The difference between the circuit shown in FIG. 1 and the circuit shown in FIG. 2 is the configuration of the power supply voltage.

The circuit shown in Figure 1 has a dual-mode DC power supply of ±E volts with respect to ground potential, and the circuit shown in Figure 2 has a single-mode DC power supply of 2E volts with respect to ground potential. . In a single mode power supply, a method is used in which the power supply potential is divided by a pair of capacitors C1 and C1 having approximately the same capacity to obtain an intermediate potential terminal.

In this case, the pair of capacitors C1, C1 also functions as a backflow power buffer.

The pair of positive/negative switches of the inverter of the EL light emitting power supply circuit of the present invention has a zero cross mechanism that automatically closes (turns off) the channel when the current value becomes zero.

A zero-cross switch element and/or a zero-cross circuit is used as the zero-cross mechanism.

In the illustrated example, each of the pair of zero-cross switches T1 and T2 is composed of a zero-cross switch element.

And the inverter consists of a pair of zero cross switches T
It has a bypass channel with a pair of reverse current bypass diodes D1 and D2 that bypass T1 and T2, respectively, and is connected to a DC input power supply of ±E volts or 2E volts.

As long as the inverter used in the present invention has the above-mentioned configuration, other configurations are not particularly limited, and any known inverter may be used. Then, the zero cross switches T1 and T2 are alternately opened (ON) by the pulse oscillation wave f having the switching frequency f.

As the zero-crossing element used in the zero-crossing switches T1 and T2, a thyristor having a withstand voltage of 2E volts or more, such as a reverse blocking three-terminal thyristor (SCR) or a bidirectional three-terminal thyristor (TRIAC), is used.

Electrodynamics (dynamism) in such a circuit configuration
To understand this, the LC shown in Figure 4, where the zero cross switch T1 of the inverter circuit is regarded as the switch S, is necessary.
The easiest way to understand this is to consider an R circuit.

In the circuit shown in FIG. 4, L is an inductor, C is an EL, and R is an R equivalent component in the circuit. The R equivalent components include the sheet resistance of the EL, the ON resistance of the switch element, the DC resistance of the coil, the magnetic flux loss, and the luminous flux divergence of the EL.

In Fig. 4, the dynamism of the voltage VEL of C and the current I flowing through the circuit after the switch S is turned ON or closed is as shown in Fig. 5 if R is less than a certain value. exhibits vibration phenomena.

From the mathematical model, the time constants determined by L, C, and R are assumed to be τ1 and τ0 (τ0=2τ1).

And the angular frequency ω is Then τ1 is τ1=√(π/ω) is given by

In addition, the vibration phenomenon can be obtained by This is the case when R<2√(L/C).

In the embodiment of the EL light emitting power supply circuit of the present invention, triac elements were selected as each of the zero cross switches T1 and T2.

As is well known, once a triac element is in the ON state (open state), even if the trigger voltage (gate voltage) is reduced to zero, if the current does not become zero, it will be in the OFF state (closed state).
I won't go back.

Therefore, considering the LCR circuit shown in FIG. 6 in which the switch S is composed of a triac element, when a pulsed trigger voltage is applied to the gate of T1 at t=0, a current I flows, and the current I is zero in T1. OFF for the first time at τ1
(closed), and does not turn on (open) after τ1 until the next trigger pulse comes. During the time period τ1≦t≦τ0 after T1 becomes OFF, the reverse current is recovered to the power supply side through the bypass channel, but t=
The recharge-up current after τ0 is blocked by the action of the reverse bypass diode D1 in the bypass channel, and the current dynamism is eventually terminated at τ0 (
automatically locked).

The above operation modes are shown in FIG. 8 in concrete correspondence with the circuit shown in FIG. 1. In FIG. 8, VC indicates the voltage waveform of the trigger pulse. When the trigger pulse P+ is applied to the gate of the triac T1, the positive side channel T1 is opened (ON), a current I+ flows, and when EL is charged to the peak voltage VP, the current I+ becomes zero.
T1 is closed (OFF).

Then, the reverse current I+D returns to the positive power supply side through the reverse bypass diode D1 of the bypass channel.

As a result, the power (charge) corresponding to the reverse current I+D shown by the hatched area in the figure is recovered as surplus power. In this case, due to the action of D1, auto-lock is achieved at τ0 when feedback is completed, and the positive side dynamism ends.

Note that as the charge is recovered from EL as a backflow current, the potential of EL decreases from VP, and at t=t0,
VEL=ΔV, and it will not fall below this value. That is, when the capacitance of EL is C, energy corresponding to CΔV2/2 is lost every half cycle as unrecovered lost energy due to charge recombination.

Therefore, the lower the ΔV value, the better the recovery efficiency.

Of course, ΔV cannot be reduced to zero, but every half cycle C(
This means that energy corresponding to VP2-ΔV2)/2 was recovered as a backflow current.

Then, when the trigger inversion pulse P- comes after T seconds, the triac T2 of the minus side channel is opened (ON).
However, similar dynamism is achieved as shown in FIG.

Here, the dynamism of current and voltage is unrelated to the time width T except for the condition τ0≦T, and the lighting frequency f of the EL is f
= 1/2T.

Therefore, τ0≦T, that is, f≦1/2τ0=1/4τ1
The lighting frequency f of the EL panel can be set arbitrarily within the range of
The lighting brightness of the EL can be set arbitrarily and variably within this range.

Incidentally, in the case of an EL light emitting power supply circuit in which a pair of positive/negative switches of an inverter are configured with a pair of complementary power MOSFETs, for example, reverse current feedback and auto-lock to prevent recharging can be achieved, and the same effect as in the present invention can be achieved. dynamism can be obtained.

However, in order to obtain the same dynamism as in the present invention, it is necessary to satisfy the following conditions, assuming that the pulse width of the signal pulse applied to one switch is T2.

As can be seen by comparing the condition τ0≦T of the present invention, in the case of an inverter using FET as a switch, τ1≦T
The weighting condition is 2≦τ0.

In other words, in the present invention, there is no restriction on the pulse width of the signal pulse applied to the switch, and as a result, the lighting brightness of the EL can be set much more easily.

The fact that the dynamism of the EL light emitting power supply circuit of the present invention is independent of the time width T means that even if the interval T becomes smaller, the waveforms of the currents I+ and I- simply approach each other, and the I
This means that the + and I- current waveforms themselves do not change.

The waveform of the voltage VEL also has only a peak interval that approaches each other, but the values of VP and ΔV and the values of τ1 and τ0 do not change.

Next, an example of the second aspect of the present invention will be described.

The second aspect also differs from the first in that it realizes a reverse current, and that the automatic locking of its dynamism is achieved by the combination of the zero cross switch and the function of the reverse bypass diode in the reverse bypass channel.
The principle is the same as the embodiment.

However, in this case, consideration is given especially to the case where the DC power supply voltage ±E volts or 2E volts is further increased or decreased, or the voltage is varied to be increased or decreased to apply an AC load to the EL panel.

FIG. 3 shows an embodiment of the EL light emitting power supply circuit of the second aspect.

In this circuit, in the embodiment of the first aspect, the inductor L is replaced with a transformer T, and a bipolar capacitor C3 is provided at the position of EL to constitute a primary side circuit.
The EL is turned on by the AC power on the next side.

However, in Fig. 3, in addition to the EL between the output terminals on the secondary side of the transformer T, there is also a compensation inductor L' in series with the EL.
An example of inserting is shown below.

In this case, the capacitance of the bipolar capacitor C3 and the coupled inductance of the transformer T, which couples the EL panel and the compensation inductor L' on the secondary side, are the series LC component converted on the primary side.

Therefore, the dynamism in this circuit is explained by comparing the inductance of L to the coupled inductance of the transformer T and the capacitance of C to the capacitance of the bipolar capacitor C3 in the LCR circuit shown in FIGS. 4 and 6.

In addition, in Fig. 3, the winding ratio of the transformer T is made variable so that the load voltage of the EL can be variably set, and the inductance of the compensation inductor L' can also be set variably, but the EL lighting brightness depends on the frequency. If adjustment is selected, it is sufficient that the winding ratio of the transformer T and the inductance of the compensation inductor L' are fixed, and furthermore, L' may be unnecessary.

This second aspect is applicable when the power supply voltage is low, for example 12V, and it is difficult to use a step-up DC-DC converter.
Alternatively, even if it can be used, the power consumption inside the DC-DC converter is too large to be ignored as a part of the power consumption of the entire system, and it is effective as a boosting method that does not use the DC-DC converter.

Further, the signal for turning on (opening) the zero cross switches T1 and T2 of the EL light emitting power supply circuit of the present invention may be any conventionally used signal such as an optical signal, in addition to the above-mentioned pulsed trigger voltage. , will be explained using the above trigger voltage as an example.

As shown in FIG. 1, from the pulse oscillator 1, the frequency f
, pulse oscillation waves 11 that are generated alternately with a period of 2T are divided into positive pulses and negative pulses by a pulse selection circuit.

At this time, the plus pulse selection circuit 2 selects only the plus pulses and applies the plus pulses 21 at intervals of 2T to the gate of T1.

Further, the negative pulse selection and inversion circuit 3 selects and inverts only the negative pulse, and applies negative inversion pulses 31 at intervals of 2T, whose phase is shifted by T from the positive pulse, to the gate of T2.

Note that f and T may be set to match the desired lighting brightness and to satisfy the condition of f≦1/2τ0.

In the present invention, there is no particular restriction on the DC power source used.

However, the present invention is particularly effective in terms of power saving when a secondary battery power source or a solar battery power source is used as a power source.

However, recharging the secondary battery with the reverse current not only shortens the current life but also may be difficult due to the characteristics of the battery itself.

Therefore, when using a battery as a power source, diodes D3 and D4 are inserted between the power source and zero cross switches T1 and T2, as shown in FIG. 9, and a reverse power buffer is used. as capacitor C1, C
It is preferable to provide 1.

Alternatively, as shown in FIG. 8, second switches Tr3 and Tr4, which switch at the same frequency f as T1 and T2 and are closed during reverse flow, are provided on the side of the buffer capacitors C1 and C1 and the power supply. It is also preferable to connect an inverter. At this time, phase adjustment inductors L3 and L are added between the inverter and the power supply.
One solution is to provide 3.

Alternatively, as shown in FIG. 10, if an inductor L3 is provided after the second inverter having Tr3 and Tr4 connected to the power source, only one inductor L3 is required.

Note that the switches Tr3 and Tr4 of the second inverter include transistors, power transistors, and MOSFETs.
, power MOSFET, etc., and usually a push-pull inverter is configured by Tr3 and Tr4 as shown in the figure.

The above is just one example of the present invention, and all electrical circuits equivalent to the above configuration are included in the present invention.

<Effects of the Invention> According to the present invention, the surplus power stored in the EL is recovered to the power supply side as a reverse current before the channel on the opposite electrode side is opened (ON), so the EL lighting efficiency is reduced. Much improved.

In addition, no or very little current flows in the circuit at the instant of the inverter switch opening/closing operation, eliminating switching energy loss.

Therefore, energy efficiency is further increased with a synergistic effect, heat generation during switching is eliminated, and safety is increased. Since heat generation is eliminated, there is no need to provide a heat dissipation means, so miniaturization is possible, and a fairly large EL area can be illuminated with a small ignition device.

The inverter of the EL light emitting power supply circuit of the present invention has a volume of approximately 3 cm x 4 cm x 8 cm, for example, and has a capacity of 400 cm.
A blue-green EL panel of about 0 cm2 to 1 m2 can be lit, and in addition, the lighting brightness can be arbitrarily set within the range of about 5 cd/m2 to 50 cd/m2, for example, by changing the frequency of the inverter.

In this way, the same inverter can light up any EL area, and the lighting brightness can be set arbitrarily, so the mass production and productivity of the EL lighting system are significantly improved.

The present inventors conducted various experiments in order to confirm the effects of the present invention. An example is shown below.

EXPERIMENTAL EXAMPLE An EL light ignition device comprising the basic circuit shown in FIG. 2 was manufactured.

The input power to the EL light is a 12V single DC power supply, which is converted to 1 by a step-up single mode DC-DC converter.
The voltage was boosted to 40 volts and used as the input power source for the inverter. Therefore, in FIG. 2, E=70 volts.

Note that the lighting frequency can be variably set by adjusting the volume, and was changed depending on the area of the EL and the like.

For L, an inductor with a wire wound around a ferrite-based shielded pot core was used.

The inductance of the inductor was 29.5 mH, and the DC resistance was about 4Ω.

The outer dimensions of the case of the EL light fixture manufactured by incorporating these parts were approximately 35 mm x 60 mm x 80 mm, and no measures against heat generation such as a heat sink were taken.

EL panels were prepared in two sizes, A and B, as shown below.

EL panel A: External dimensions 720mm x 550mm Light emitting area 3
766.0cm2 EL panel B: External size 550mm x 550mm light emitting area 2
851.4 cm 2 The EL used was one manufactured by Fukubi Kagaku Co., Ltd. that emitted green light, and the sheet resistance value of each EL was about 80Ω.

Then, lighting experiments were conducted using four types of combinations: A+A (two A panels in parallel), B+B (two B panels in parallel), and A and B. Table 1 shows the input power (W), lighting efficiency (Lm/W), and lighting frequency to the EL lamp when it is lit with a surface illuminance of 10Lx.

As is clear from the above experimental results, the EL lighting efficiency when using the EL light emitting power supply circuit of the present invention falls within the range of approximately 3 to 4 lumens/watt, which is a 3 to 4 times improvement in efficiency over the conventional technology. It can be seen that this has been achieved.

And relatively small, i.e. external size 35mm x 60m
With a case size of approximately m x 80 mm, all of the above combinations of areas can be set to be illuminated with the same illuminance, and such an EL light has never existed before.

Moreover, there was almost no heat generation, and the rise in the surface temperature of the light ignition device relative to the outside air was within IDEG 8 hours after the light was turned on.

Next, various experiments were conducted using the EL light ignition device having the circuit configuration shown in FIG.

The EL panels are those with green luminescent color manufactured by Fukubi Chemical Co., Ltd., and the following A1, A2, B1, B2, C, D1, and D2 are used.
, E, F and G were used. A plurality of sheets with different sheet resistance values were prepared for each.

EL panel A1: Light emitting area 3766.0 cm2 EL panel A2: Light emitting area 3766.0 cm2 EL panel B
1: Light emitting area 2851.4cm2EL panel B2: Light emitting area 2851.4cm2EL panel C: Light emitting area
1367.4cm2EL panel D1: Light emitting area 204
4.4cm2EL panel D2: Light emitting area 2044.4
cm2EL panel E: Light emitting area 1094.4cm2E
L panel F: Light emitting area 678.4cm2EL panel G
: Light emitting area: 528.0 cm2 Further, the inductance of L was 30 mH, and the voltage was boosted to ±50 volts by a dual mode DC-DC converter to serve as an input power source for an inverter.

And A1+A1, B1+B1, A2, D1+E, B
Table 2 shows the set lighting frequencies when the combinations of 2, D2, C, F and G are illuminated with the same lighting illuminance of 10Lx.

Note that Table 2 also lists the in-circuit R equivalent components such as the sheet resistance value of the EL panel.

As is clear from Table 2, in this method, one EL light emitting power supply circuit, that is, one EL ignition device, can generate ELs with various areas from A1+A1 to G, and furthermore, ELs with different sheet resistance values. It can be seen that it is possible to turn on the light at the desired illuminance simply by adjusting the frequency.

For the different EL areas of A1+A1 to G, EL lighting efficiencies of about 3 to 4 lumens/watt were obtained, respectively.

Note that the EL lighting efficiency in the conventional technology is 1 lumen/watt or less.

The above results clearly demonstrate the effects of the present invention.

[Brief explanation of the drawing]

FIG. 1, FIG. 2, FIG. 3, FIG. 9, and FIG. 10 are circuit diagrams showing different examples of the EL light emitting power supply circuit of the present invention. 4 and 6 are circuit diagrams showing LCR series circuits, respectively. FIGS. 5 and 7 are graphs showing temporal changes in voltage VEL and current I of capacitor C in the LCR series circuit, respectively. FIG. 8 is a graph showing trigger pulses added to the zero cross switches T1 and T2, and temporal changes in the voltage VEL and current I of EL. Explanation of symbols Tr3, Tr4...Switch T1, T2...Zero cross switch EL...EL T...Transformer L, L', L3...Inductor D1, D2, D3, D4 Diode C1, C3...Bipolar capacitor 1...Pulse oscillator 11...Pulse Oscillation wave 2...Pulse pulse selection circuit 21...Plus pulse 3...Minus pulse selection inversion circuit 31...Minus inversion pulse Patent applicant Daichi Co., Ltd. Agent for Nippon Beam Electronics Co., Ltd. Patent attorney Yoichi Ishii Patent attorney Tatsuya Masuda

Claims (10)

[Claims] 1. An EL including an EL or an EL string having capacitive load characteristics and an inductor as part of the series-coupled component.
A circuit is configured, one end of this EL circuit is coupled to a combined output terminal of an inverter, the other end is coupled to an intermediate potential terminal or a ground terminal of a DC input power source of the inverter, and a pair of positive and negative switches of the inverter are connected, respectively. It is configured using a zero cross switch mechanism that automatically closes the channel when the current value becomes zero, and each of the positive and negative switches is provided with a bypass channel having a reverse current bypass diode for bypassing the zero cross switch mechanism. An EL light emitting power supply circuit characterized by the following. 2. An EL circuit including an EL or EL string having capacitive load characteristics is configured as part of the series-coupled component, and this EL circuit is coupled to the output terminal of the secondary side of the transformer, and the EL circuit is bipolar. A capacitor is connected in series to the primary side of the transformer to form a primary circuit, one end of this primary circuit is connected to the combined output terminal of the inverter, and the other end is connected to the intermediate potential terminal of the inverter's DC input power supply or to ground. The pair of positive and negative switches of the inverter are connected to the terminals, and each of the pair of positive and negative switches of the inverter is configured using a zero-cross switch mechanism that automatically closes a channel when the current value becomes zero, and each of the positive and negative switches is provided with this zero-cross switch mechanism. An EL light emitting power supply circuit comprising a bypass channel having a reverse current bypass diode for bypassing. 3. At the output terminal of the secondary side of the transformer, an EL
3. The EL light emitting power supply circuit according to claim 2, wherein a compensating inductor is inserted in series with the EL string. 4. The EL according to claim 1, wherein a pair of capacitors having equal capacities are connected in parallel to the other end of the EL circuit, and the other end of the pair of capacitors is cross-linked between DC input power supply terminals of an inverter. Light emitting power supply circuit. 5. A device according to claim 2 or 3, wherein a pair of capacitors having equal capacities are connected in parallel to the other end of the primary side circuit, and the other end of the pair of capacitors is cross-linked between the DC input power terminals of the inverter. The EL light emitting power supply circuit described. 6. A combination of the EL circuit or the primary side circuit, a zero-cross switching mechanism of a pair of positive and negative switches of the inverter, and a bypass channel having a reverse bypass diode allows the EL, EL string, or bipolar 6. The EL light emitting power supply circuit according to claim 1, wherein the electric charge charged up in the capacitor is recovered to the same power supply side as a reverse current. 7. The action of the inductance of the EL circuit or the primary side circuit suppresses a steep rise in the current value during the opening operation of the pair of positive and negative switches of the inverter, and the action of the zero cross switch mechanism suppresses the sudden rise of the current value when the pair of positive and negative switches of the inverter are opened. 7. The EL light emitting power supply circuit according to claim 1, wherein switching energy loss accompanying the opening/closing operation of the switch of the inverter is reduced by reducing a current value during the closing operation of the inverter. 8. The EL light emitting power supply circuit according to claim 1, wherein the switching frequency of the inverter is set or variably set to set or variably set the lighting brightness of the EL or EL row. 9. One or more of the input power supply voltage of the inverter, the winding ratio of the transformer, and the inductance of the compensation inductor are set or variably set to set the lighting brightness of the EL or EL string. 9. The EL light emitting power supply circuit according to claim 1, wherein the EL power supply circuit has variable settings. 10. The EL circuit according to claim 1, wherein the EL circuit has a coupling terminal to which the EL or EL column can be detachably coupled, and the EL or EL column is coupled to the coupling terminal. The EL lighting circuit is composed of E
Power supply circuit for L.