JP3441904B2 - Lighting circuit device and light emitting device for low pressure discharge lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting circuit device for a low-pressure discharge lamp such as a neon lamp and a light emitting device provided with the lighting circuit device.

[0002]

2. Description of the Related Art There are various types of display devices used for displaying information, such as automobiles and electric bulletin boards, and low-pressure discharge lamps as light sources mounted on the display devices have also been diversified. Technological advances have been made, such as the adoption of an inverter device for the circuit for lighting this low-pressure discharge lamp. There was also a problem such as the need for.

As shown in FIG. 1, a lighting circuit device C for a low-pressure discharge lamp, for example, a low-pressure neon discharge lamp, includes a DC power supply 11, a voltage stabilization circuit 12, a power supply voltage abnormality detection circuit 13, and an ON / OFF control circuit 14. , Voltage-to-pulse width conversion circuit 15, FET drive circuit 16, error detection circuit 17,
The circuit C is composed of a pulse transformer 18, a smoothing circuit 19, and a load abnormality detecting circuit 20. The output terminal of the circuit C is connected to the electrodes A1, A2 of the low-pressure discharge lamp L.

The terminal voltage of the lamp L of the lighting circuit device C fluctuates minutely due to the voltage fluctuation of the power supply 11 and the negative resistance of the lamp L, and the following means are used as means for correcting this fluctuation. Things like that were done. For example, as shown in FIG. 6, an error detection circuit 17 sets a reference voltage in accordance with a lamp current, detects a voltage fluctuating by a resistor R1 connected in series to a lamp L, and compares the comparison difference value with an amplifier Am. Was amplified and read. The read data signal is fed back to the voltage-to-pulse width conversion circuit 15 to adjust the pulse duty ratio to adjust the lamp current. However, when this amplifier Am is used, it has disadvantages such as an increase in the number of components and a complicated circuit.

Further, in the oscillation circuit of the FET drive circuit 16, a time of 5 to 10 mSec from application of voltage to the lamp L to oscillation due to the internal resistance of the general-purpose timer IC and the time constant of the external capacitor. In short, there was a problem that the discharge of the lamp L was delayed.

[0006]

SUMMARY OF THE INVENTION The present invention provides a lighting circuit device which can stably light a low-pressure discharge lamp by improving the above-mentioned error detecting circuit and has no delay in starting discharge, and a lighting circuit device using this lighting circuit device. It is an object of the present invention to provide a light emitting device.

[0007]

SUMMARY OF THE INVENTION A low-pressure discharge lamp according to the present invention.
The lighting circuit device of DC power supply, voltage stabilization circuit, voltage-
Pulse width conversion circuit, switching element drive circuit, error detection
Lighting circuit with output circuit, pulse transformer and smoothing circuit
Lighting circuit with a low-pressure discharge lamp connected to the output end of the road
The error detection circuit further includes a voltage detection unit ,
The voltage detecting unit, to one of the electrodes of the low-pressure discharge lamp
Are connected, a constant current element lamp current is supplied, the constant
Is connected in parallel to the current element, the lamp current is supplied
That it consists of a detection resistor, error power that is generated in the detection resistor
Feedback to the voltage-pulse width conversion circuit
It is characterized by the following.

When the error detection circuit goes out of a predetermined voltage range as a reference, the error detection circuit detects an abnormality and turns the signal ON / OF.
Issue to F control circuit.

A lighting circuit device for a low-pressure discharge lamp according to a second aspect of the present invention is characterized in that the constant current element comprises a constant current diode.

[0010] An error voltage is detected by an excessive current flowing through the detection resistor than the reference current value.

A lighting circuit device for a low-pressure discharge lamp according to a third aspect of the present invention is characterized in that the constant current element comprises a constant current transistor.

According to the second aspect of the present invention, the same operation as described above is achieved.

A lighting circuit device for a low-pressure discharge lamp according to a fourth aspect of the present invention is characterized in that the FET drive circuit has a capacitor connected between a power supply terminal and a control terminal.

The time from when the power is turned on until the operation is stabilized is reduced.

The fact that the time required for stabilization is short means that the time required for lighting is shortened.
In practical terms, for example, in a car or the like, the time from when the brake is depressed to when the stoplight is turned on is reduced, so that safety is improved.

The light emitting apparatus according to claim 5 of the present invention, an instrument, a low-pressure discharge lamp provided in the instrument, the low
A lighting circuit device for a low-pressure discharge lamp according to any one of claims 1 to 4 connected to a high- pressure discharge lamp.

Since there is provided a lighting circuit device for a low-pressure discharge lamp having the same effect as described in any one of claims 1 to 4, stable lighting and starting characteristics are exhibited.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a lighting circuit device for a low-pressure discharge lamp according to the present invention will be described below with reference to the drawings.
The present invention basically includes the same lighting circuit as in FIG. 1 described above, and FIGS. 2 and 3 each show a specific embodiment of the error detection circuit.

FIG. 1 shows a low-pressure neon discharge lamp, for example.
The lighting circuit device C of the low-pressure discharge lamp L is shown in FIG.
1 is a DC power supply, 12 is a voltage stabilization circuit, 13 is a power supply voltage abnormality detection circuit, 14 is an ON / OFF control circuit, 15 is a voltage-pulse width conversion circuit, 16 is an FET drive circuit, 17 is an error detection circuit, 18 Is a pulse transformer, 19 is a smoothing circuit, 20 is a load abnormality detection circuit, and cold cathode electrodes provided at both ends of the low-pressure discharge lamp L at the output end of this circuit C
A1 and A2 are connected.

The voltage stabilizing circuit 12 supplies a stabilized voltage to a circuit requiring a stable voltage.
The circuit 12 always supplies a stabilized voltage even when a power supply voltage abnormality detection circuit 13 and a load abnormality detection circuit 20 described later operate, and the voltage range in which the power supply voltage abnormality detection circuit 13 operates normally A wider voltage range. When the power supply voltage abnormality detection circuit 13 is out of the reference voltage range, the power supply voltage abnormality detection circuit 13 detects the abnormality and turns the signal ON / OFF.
To force out to the OFF control circuit 14.

When an abnormal signal is input from the power supply voltage abnormality detecting circuit 13 or the load abnormality detecting circuit 20, the ON / OFF control circuit 14
Stop output of

The voltage-to-pulse width conversion circuit 15
When the signal of the N / OFF control circuit 14 is transmitting a signal within the normal operation range, the pulse width is changed by the voltage from the error detection circuit 17. And an error detection circuit 1
When the voltage from 7 is low, the pulse width is controlled to be long, and when the voltage is high, the pulse width is controlled to be short. The period is set to be substantially constant even when the voltage from the error detection circuit 17 changes.

When the signal from the ON / OFF control circuit 14 indicates an abnormality, no pulse is output regardless of the signal from the error detection circuit 17, and the output is stopped. (No voltage is supplied to the lamp L.) Further, the FET drive circuit 1
Reference numeral 6 outputs a signal for driving the switching FET, and its waveform is almost the same as that of the voltage-to-pulse width conversion circuit 15, but it is a low-impedance circuit for reliably turning on / off the FET.

The error detecting circuit 17 detects the difference between the current value to be passed through the lamp L and the current actually flowing, and adds a constant value to the proportional voltage to convert the voltage into one pulse width. Output to the circuit 15.

The pulse transformer 18 boosts a low voltage pulse to a high voltage, and the voltage is 1000 to 3000.
V or so.

The smoothing circuit 19 smoothes a voltage obtained by rectifying the pulsed alternating current output from the transformer 18 with a diode 19a, and the output of the smoothing circuit 19 is supplied to the electrodes A1 and A2 of the lamp L through a resistor 19b. And is connected to the load abnormality detection circuit 20.

The load abnormality detection circuit 20 is connected to the lamp L
Is detected when the voltage is abnormally increased when the wire is broken or the wire is cut, and when the wire is short-circuited to the low voltage side of GND or the lamp L, the voltage becomes abnormally low.
It is output to the N / OFF control circuit 14.

During normal operation, the power supply voltage abnormality detection circuit 13
And the signal from the load abnormality detection circuit 20 is not in an active state, the signal of the ON / OFF control circuit 14 is not active, and the circuit of the voltage / pulse width conversion circuit 15 Is output to perform the control operation (lamp current stabilization operation).

The load abnormality detection circuit 29 outputs an abnormality signal even when a lamp L other than a regular lamp (rated) is connected.

Then, even if the terminal voltage of the lamp L of the lighting circuit device C fluctuates due to the fluctuation of the power supply voltage or the influence of the negative resistance of the lamp L, the error detection circuit 17 shown in FIG. A reference voltage is set by a constant current diode 17a as a constant current element connected to one electrode A2 of the lamp L and a resistor 17b, a fluctuating voltage is detected, and the comparison difference value is read.

Then, the read data signal is fed back to the voltage-to-pulse width conversion circuit 15 to adjust the conduction time of the FET (switching element). Therefore, in the case of this method, since the error voltage is high, there is no need for amplification, and the number of parts is reduced, so that the circuit configuration can be simplified. In the figure, 17c is a capacitor for preventing malfunction, and 17d is a Zener diode.

FIG. 3 shows a constant current element instead of the constant current diode 17a in FIG.
7e, and has the same operation and effect as the above embodiment.

Further, according to the present invention, as shown in FIG. 4, in the oscillation circuit of the FET drive circuit 16, a general-purpose IC IC 16a
Between the power supply terminal and the control terminal due to the internal resistance of the power supply and the time constant of the external capacitor 16b.
By interposing 6c, the voltage of the control terminal can be quickly raised, a section with a narrow pulse width immediately after the power supply is applied can be shortened, and a discharge start delay can be shortened.

In the experiment of the inventor, the time from application of a voltage to the lamp L to oscillation can be made within 1 mSec.

FIG. 5 is an explanatory view showing an embodiment of the light emitting device D of the present invention. FIG. 5 shows a light-emitting device D formed as a stop lamp of an automobile G. This light-emitting device D accommodates a reflector in which a low-pressure discharge lamp L is disposed together with a lighting circuit device C in a housing constituting an appliance. . When a voltage is applied to the discharge lamp L of the light emitting device D via the lighting circuit device C, the lamp L is stably lit with good startability, and excellent light emission characteristics can be obtained until the end of its life.

The present invention is not limited to the above embodiment. For example, the low-pressure discharge lamp is not limited to the low-pressure neon discharge lamp, but may be another type of discharge lamp.

The light emitting device is not limited to a stop lamp of an automobile, but may be a light emitting device for other uses.

[0038]

According to the first to third aspects of the present invention, the error voltage is read by using a constant current element and a resistor instead of the amplifier, so that the number of components of the read circuit can be reduced and the circuit configuration can be simplified. .

According to the fourth aspect of the invention, the voltage of the control terminal can be quickly raised, and the discharge start delay time can be set within 1 mSec.

According to a fifth aspect of the present invention, there is provided a lighting circuit for a low-pressure discharge lamp having the same effect as in any one of the first to fourth aspects, so that the light emitting device has stable lighting and starting characteristics. Can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic circuit diagram showing a lighting circuit device for a low-pressure discharge lamp.

FIG. 2 is a wiring diagram showing an embodiment of an error detection circuit portion in the lighting circuit device of the present invention.

FIG. 3 is a wiring diagram showing another embodiment of the error detection circuit portion in the lighting circuit device of the present invention.

FIG. 4 is a wiring diagram showing an embodiment of an FET drive circuit in the lighting circuit device of the present invention.

FIG. 5 is an explanatory diagram in the case where the light emitting device of the present invention is used as a stop lamp of an automobile.

FIG. 6 is a wiring diagram showing a conventional FET drive circuit portion in the lighting circuit device.

[Explanation of symbols]

C: lighting circuit device L: low-pressure discharge lamp (low-pressure neon discharge lamp) A1, A2: electrode 11: DC power supply 12: voltage stabilization circuit 13: power supply voltage abnormality detection circuit 14: ON / OFF control circuit 15: voltage-pulse Width conversion circuit 16: FET drive circuit 17: error detection circuits 17a, 18b: constant current element (constant current diode, constant current transistor) 18: pulse transformer 19: smoothing circuit 20: load abnormality detection circuit D: light emitting device

Claims (5)

(57) [Claims] 1. A DC power supply, a voltage stabilizing circuit, and a voltage-pulse
Width conversion circuit, switching element drive circuit, error detection circuit
Circuit, a pulse transformer and a lighting circuit having a smoothing circuit.
In a lighting circuit device with a low-pressure discharge lamp connected to the output end
Te, the error detecting circuit further includes a voltage detecting unit, the
Voltage detecting unit is connected to one electrode of the low-pressure discharge lamp
The constant current element to which the lamp current is supplied and the constant current
Is connected in parallel to the element, the lamp current is supplied test
Out consists of a resistance, the error voltage generated in the detection resistor
Feedback to the voltage-pulse width conversion circuit
A lighting circuit device for a low-pressure discharge lamp. 2. The lighting circuit device for a low-pressure discharge lamp according to claim 1, wherein said constant current element comprises a constant current diode. 3. The lighting circuit device for a low-pressure discharge lamp according to claim 1, wherein said constant current element comprises a constant current transistor. Wherein said switching element driving circuit, the
2. The lighting circuit device for a low-pressure discharge lamp according to claim 1, wherein a capacitor is connected between the DC power supply and the control terminal. 5. A light-emitting device comprising: an appliance; and a lighting circuit device for a low-pressure discharge lamp according to claim 1, provided on the appliance.