JPH07135086A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To provide a discharge lamp lighting device for which at least both dispersion of detected voltage and current can be easily corrected to regulate performing power effectively. CONSTITUTION:A discharge lamp lighting device is at least provided with power control means 11, 18 for performing constant power control of power to be supplied to a discharge lamp when stationary in accordance with a lamp current and a lamp voltage of a discharge lamp 14, and a power supply means 19 to supply a DC constant voltage to an analogue circuit part of the power control means. This power supply means has a DC constant voltage changeable means R7 for output power regulation of the lighting device when stationary.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device for high-intensity discharge lamps such as high-pressure mercury lamps and metal halide lamps, and more particularly to a lighting device having a trimmer for adjusting the output power of the lighting device itself in a steady state.

[0002]

2. Description of the Related Art A discharge lamp lighting device, after being manufactured,
The power is adjusted so that the output power in the steady state will be the rated value before shipment. For this output power adjustment, as shown in FIG. 2, the rated discharge lamp 14 is actually connected to the output terminal of the lighting device 21, and the lamp voltage and lamp current are input to the power meter 22 to measure the lamp power. While performing, it is performed by adjusting the trimmer provided in the lighting device 21.

The discharge lamp lighting device is provided with a trimmer for performing such power adjustment. For example, in the lighting device disclosed in Japanese Unexamined Patent Publication No. 4-337294, a trimmer composed of a variable resistor is provided in the lamp voltage detection circuit, and power is set by adjusting the trimmer. .

[0004]

However, when a trimmer is provided in the voltage detection circuit, it is possible to correct the voltage variation and adjust the power, but it is possible to correct the current variation at all. Therefore, the adjustment range of electric power will be considerably narrowed. To improve this point, it is possible to further provide a trimmer in the lamp current detection circuit, but it is very difficult to move the two trimmers together to adjust the power, because the procedure is complicated.

The following two factors can be considered as factors of the variation in power.

One is the variation in impedance of the components used in the control circuit and the detection circuit. As the resistance for detecting the lamp current, a resistance of 1Ω or less is usually used, but such a low resistance generally has an error of ± 5% to ± 10%. Therefore, the detected current value includes at least an error more than this, but it is very difficult to correct this portion with high accuracy in the above-described conventional technique.

Another factor is variations in the power supply voltage (about 5 V) for the analog circuit used as the reference voltage and the control voltage in the control circuit and the detection circuit. Control I for switching power supply built in chopper circuit
C is a reference voltage source (for example, μPC1094 manufactured by NEC)
Is provided and in most cases the output voltage of this reference voltage source is used. However, although this power supply voltage is stable with respect to temperature, it is a fixed voltage and its value is N
EC Data Book 1993/1994 version μPC109
As shown in 4, the variation is about ± 5%. The variation of the power supply voltage results in the variation of both the detected voltage value and the detected current value, and the power varies with the product of these.

Therefore, the present invention provides a discharge lamp lighting device which can easily correct at least variations in the detected voltage value and variations in the detected current value and can efficiently perform power adjustment.

[0009]

DISCLOSURE OF THE INVENTION The discharge lamp lighting device of the present invention is a power control means for controlling the constant power of the power supplied to the discharge lamp in a steady state according to the lamp current and the lamp voltage of the discharge lamp, and the power control. At least power supply means for supplying a constant DC voltage to the analog circuit portion of the means. This power supply means has the above-mentioned DC constant voltage changing means for adjusting the output power of the lighting device in the steady state.

[0010]

By adjusting the variable means of the power supply means, the DC constant voltage supplied to the analog circuit portion of the power control means and used as the reference voltage or the control voltage is adjusted. When setting the power, the power can be easily adjusted only by adjusting the variable means, and the variations in the detected voltage value and the detected current value can be corrected at the same time, so that the power can be easily adjusted in a wide range. be able to.

[0011]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram schematically showing the construction of an embodiment of the discharge lamp lighting device of the present invention.

In the figure, 10 is a battery or a DC power supply after AC rectification, and 11 is a chopper circuit composed of a step-up or step-down DC-DC converter connected to the DC power supply 10. The chopper circuit 11 is configured such that the output current or output power is variably controlled according to the pulse-width-controlled drive signal from the control circuit unit 12, and an inverter circuit 13 is connected to its output. There is. The inverter circuit 13 outputs a direct current or an alternating current (for example, about 250 HZ) in accordance with an instruction from the drive circuit unit incorporated therein.
The high-intensity discharge lamp 14 such as a high-pressure mercury lamp or a metal halide lamp and the secondary winding of the transformer 15 for generating a high-voltage trigger are connected in series to the output. There is. The primary winding of the transformer 15 is connected to the output of the trigger pulse generation circuit 16.

Dividing resistors R1 and R2 for detecting the output voltage (corresponding to the lamp voltage) of the chopper circuit 11 are connected in parallel to the output of the chopper circuit 11. Furthermore, the chopper circuit 11 and the inverter circuit 1
A resistor R3 for detecting the output current (corresponding to the lamp current) of the chopper circuit 11 is connected in series with the resistor R3. The voltage detection signal S _V from the dividing resistors R1 and R2 and the current detection signal S _I obtained by amplifying the signal S _i from the resistor R3 by the current signal amplification circuit 17 are applied to the computer circuit 18. Has been done. The chopper circuit 11, the control circuit unit 12, the divided resistors R1 and R2, the resistor R3, the current signal amplifier circuit 17, and the computer circuit 18 in this embodiment correspond to the power control means of the present invention.

The computer circuit 18 includes an A / D converter 1
8a, a power calculator 18b mainly composed of a microcomputer, and a D / A converter 18c. After the voltage detection signal S _V and the current detection signal S _I described above are input to the A / D converter 18a and A / D converted,
It is configured to be applied to the power calculator 18b.
The control circuit unit 12 of the chopper circuit 11 has a D / A conversion unit 18
It is connected to c and is configured to be applied with the power control signal output from the power calculation unit 18b and D / A converted. The inverter circuit 13 and the trigger pulse generation circuit 16 are connected to the power calculation unit 18b and are configured to operate according to an instruction from the power calculation unit 18b. The computer circuit 18 also includes
An analog dedicated power supply circuit 19 (corresponding to the power supply means of the present invention) for supplying a constant DC voltage V _A is connected to the analog circuits of the A / D converter 18a, the power calculator 18b and the D / A converter 18c. ing.

An auxiliary power supply circuit 20 is connected to the DC power supply 10. The auxiliary power supply circuit 20 has a signal power supply of about 15 V with respect to the chopper circuit 11, the control circuit unit 12, the inverter circuit 13, the trigger pulse generation circuit 16, the current signal amplification circuit 17, the computer circuit 18, the analog dedicated power supply circuit 19, and the like. Small DC to supply voltage V _CC
A DC converter. This signal power supply voltage V _CC
Is used as a driving power source for the chopper circuit 11 and the inverter circuit 13, so that the load fluctuation is large and the accuracy is not necessarily high. Therefore, a constant voltage obtained from the analog dedicated power supply circuit 19 is used as the reference voltage and the analog signal voltage.

The analog dedicated power supply circuit 19 is mainly composed of a commercially available stabilized power supply IC element called a shunt regulator (for example, μPC1093 manufactured by NEC) IC1 and its reference voltage circuit. That is, as shown in FIG. 1, the cathode of the stabilized power supply IC element IC1 constitutes the output of the analog dedicated power supply circuit 19 and the resistor R
4 to the input of V _CC , and its anode is connected to the ground side COM. Between the cathode and the anode, a reference voltage circuit formed by connecting resistors R5 and R6 and a variable resistor R7 provided as a trimmer in series is connected in parallel. Stabilized power supply IC element IC
The reference terminal of No. 1 is connected to the connection point of the resistors R5 and R6. It is known that when the reference voltage applied to the reference terminal is V _REF and the output voltage of the stabilized power supply IC element IC1 is V _A , this output voltage V _A is given by the following equation. V _A ≈ {1 + R5 / (R6 + R7)} × V _REF

Before explaining the operation in the case of adjusting the electric power so that the electric power in the steady state becomes the rated value, the power control operation in the steady state by the lighting device of the present embodiment will be described.

The steady-state power control is for controlling the lamp power to be stable at the rated power P _S , and the power control described below is performed in real time. First, the resistor R1
And R2 from the voltage detection signal S _V corresponding to the lamp voltage at that time and the current detection signal S _I corresponding to the lamp current at that time from the current signal amplifier circuit 17 to the A / D converter 18a.
It is input to the electric power calculation unit 18b after being taken into the A / D converter. The power calculator 18b calculates the actual lamp power P _ACT from P _ACT = S _V × S _I from the data thus captured.

Next, the actual electric power P obtained by this calculation
Determine whether _ACT is larger or smaller than the rated power value P _S ,
When P _ACT > P _S , the output power (or output current) of the chopper circuit 11 is slightly decreased, and a power control signal that makes P _ACT approach P _S is output to the D / A conversion unit 18c, and analog power is output. After converting into the control signal S _P , the control circuit unit 12
Output to. When P _ACT <P _S, the D / A converter 18c outputs a power control signal that slightly increases the output power (or output current) of the chopper circuit 11 and causes P _ACT to approach P _S.
To an analog power control signal S _P and then output to the control circuit unit 12. The control circuit unit 12 outputs a drive signal whose pulse width is controlled according to the power control signal S _P to the chopper circuit 11.

Next, the power adjustment operation before shipping will be described.

The lighting device of this embodiment is connected to the discharge lamp 14 and the power meter 22 as shown in FIG. 2, and the discharge lamp 14 is lit to operate in the steady power control state. Instead of the discharge lamp, an equivalent resistance may be connected to simulate the steady power control state.

In this state, the variable resistor R7 is adjusted so that the lamp power measured by the power meter 22 becomes the rated output power of the lighting device. When the variable resistor R7 is changed, the reference voltage V _{REF of the} stabilized power supply IC element IC1 changes, and as a result, the output voltage _{VA of the} stabilized power supply IC element IC1 changes according to the above-mentioned formula. Since this voltage V _A is supplied to the analog circuits of the A / D converter 18a, the power calculator 18b and the D / A converter 18c as a control voltage and a reference voltage, the variable resistor R7, which is a single trimmer, is adjusted. By only doing so, the voltage detection value corresponding to the lamp voltage and the current detection value corresponding to the lamp current change, and power adjustment can be performed very easily. Moreover, since variations in the detected voltage value and variations in the detected current value can be corrected at the same time, the power can be easily adjusted in a wide range.

The method of controlling the lamp power is not limited to the method of the above-mentioned embodiment, and various known techniques can be applied. Further, the present invention can be applied to discharge lamp lighting devices for various purposes.

The embodiments described above are merely illustrative and not limitative of the present invention, and the present invention can be implemented in various other modified modes and modified modes. Therefore, the scope of the present invention is defined only by the claims and their equivalents.

[0026]

As described in detail above, according to the present invention, the power control means for controlling the constant power of the power supplied to the discharge lamp in the steady state according to the lamp current and the lamp voltage of the discharge lamp, and the power control. The analog circuit section of the means includes at least power supply means for supplying a constant DC voltage, and the power supply means has a constant DC voltage varying means for adjusting the output power of the lighting device in a steady state. Therefore, the voltage detection value corresponding to the lamp voltage and the current detection value corresponding to the lamp current are changed only by adjusting the variable means, so that the power adjustment can be performed very efficiently and easily. Moreover, since variations in the detected voltage value and variations in the detected current value can be corrected at the same time, the power can be easily adjusted in a wide range.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing a configuration of an embodiment of a lighting device of the present invention.

FIG. 2 is a block diagram showing a connection form when performing power adjustment.

[Explanation of symbols]

 10 DC power supply 11 Chopper circuit 13 Inverter circuit 14 Discharge lamp 15 Transformer for generating high voltage trigger 16 Trigger pulse generation circuit 17 Current signal amplification circuit 18 Computer circuit 19 Analog dedicated power supply circuit 20 Auxiliary power supply circuit IC1 Stabilized power supply IC element R7 Variable resistance

Claims (1)

[Claims] 1. A power control means for constant power control of electric power supplied to the discharge lamp in a steady state according to a lamp current and a lamp voltage of the discharge lamp, and a constant DC voltage is supplied to an analog circuit part of the power control means. Discharge lamp lighting device, characterized in that the power supply device has at least the DC constant voltage changing means for adjusting the output power of the lighting device in a steady state. .