JP2006278203A - Lighting device of high pressure discharge lamp, and electronic equipment using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a high pressure lighting device and an electronic equipment using it inexpensive and down-sized, and improve performance and lifetime of a lamp by inexpensively making brightness of the lamp constant and with high precision by a simple circuit constitution. <P>SOLUTION: In the high voltage lamp lighting device, an electric power control circuit takes a lamp 11 electric current into a differential amplifier by a level shift circuit 30, inexpensively makes the brightness of the lamp constant and with the high precision by the simple circuit constitution, and stabilizes the control. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lighting device for a high-pressure discharge lamp that is lit by applying a high-pressure pulse to a high-pressure mercury lamp, a metal halide lamp, or the like, and an electronic apparatus such as a data projector using the same.

  The high-pressure discharge lamp (lamp) is small and can provide high brightness, but the lamp voltage changes easily due to variations in physical properties such as electrodes and high-pressure gas, temporal changes, and temperature, and the brightness tends to change. Therefore, a high-pressure discharge lamp device that constantly supplies constant power to the high-pressure discharge lamp to stabilize the brightness is required.

  FIG. 8 is a block diagram showing the configuration of the high pressure discharge lamp lighting device. In FIG. 8, in order to supply constant power to the high pressure discharge lamp 11, the power from the DC power source 1 is controlled by the DC-DC converter 50 and connected to the high pressure discharge lamp 11 via the AC conversion circuit 51. The DC-DC converter 50 is controlled by the control circuit 25. The control circuit 25 constantly detects the lamp voltage 55 and the lamp current 56 of the high-pressure discharge lamp 11, and outputs a PWM control signal 15c so that the DC-DC converter 50 supplies constant power. The electric power from the DC power source 1 is converted into a high frequency voltage of several tens of kHz by the DC-DC converter 50 and smoothed to obtain lamp output power. Also, an igniter circuit 6 that is first lit by applying a high voltage (about 20 kV) is connected to the high-pressure discharge lamp 11 via an AC conversion circuit 51. The AC conversion circuit 51 includes four switching elements, and each switching element is switched and controlled by a driving circuit 52 to supply AC power to the high-pressure discharge lamp 11. The lighting waveform generation circuit 17 outputs a rectangular wave signal 24 of several tens to hundreds of tens Hz from the microcomputer 17a, and generates a slope signal 18c for reducing lamp flicker.

  As a result, the AC lamp current of the high-pressure discharge lamp generates a current that increases in a slope from the start of the half cycle, and the electrode temperature of the high-pressure discharge lamp increases to a high value immediately before the polarity reversal in the latter half of this slope current. As a result, the discharge arc is generated from the same location, and the stability of the discharge arc is increased to suppress flicker of the high-pressure discharge lamp.

Here, assuming that the lamp voltage (Vla), the AC lamp current (Ila), the slope signal (Fla), and the lamp power (Pla), this control is such that Pla = Vla × Ila / Fla = constant.

Therefore, the relationship between the AC lamp current (Ila) and the lamp voltage (Vla) is Ila = Pla × Fla / Vla (because Pla × Fla = constant).
When the lamp voltage (Vla) increases, the AC lamp current (Ila) decreases in inverse proportion.

  The previous control circuit 25 detects the lamp voltage 55 and the lamp current 56, multiplies the two signals by using the multiplier 16, compares the output result with the reference value, and outputs the PWM control signal 58. The DC-DC converter 50 was controlled.

  FIG. 9 shows a circuit configuration diagram of a high pressure discharge lamp lighting device by a control circuit 25 including an equivalent circuit of a multiplier.

  The ramp voltage 55 is divided by resistors 55a and 55b, converted to a current (I1) by a resistor 56a via an amplifier (buffer) 56, and passed through the transistor 25d using the amplifier 25a. The lamp current is amplified by the amplifier 26, converted into a current (I2) by the resistor 26a, and passed through the transistor 25f using the amplifier 25h. The currents I1 and I2 are LOG-converted and added. The output is the output current (I3) of the transistor 25e and is subjected to inverse LOG conversion and becomes an output voltage by the amplifier 25q.

  I3 = I1 × I2.

Further, the slope signal 18 for reducing flicker that changes the brightness of the lamp is also converted into a current (I4) by the resistor 18d and passed through the transistor 25g using the amplifier 25n, so that I3 = I1 × I2 / I4. A current waveform proportional to the signal 18 is obtained.

  As described above, the multiplier 16 (in FIG. 9, the circuit obtained by removing the amplifier 15 and the amplifier 25q from the control circuit 25) is an IC, but the circuit configuration is complicated, and the negative power supply 25V (−12V, etc.) Since the current is LOG-converted-inverse-LOG-converted using the characteristics of the transistors, each transistor varies and the selection is necessary and expensive.

  Therefore, in the circuit configuration diagram of the high pressure discharge lamp lighting device in FIG. 1, the lamp current 56 is taken into the differential amplifier by the level shift circuit and the circuit configuration is simple and has a high accuracy.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
Japanese Patent No. 3326968

  Here, in recent years, electronic devices have been further miniaturized, and a high-performance high-pressure discharge lamp lighting device is desired at a low cost.

  As described in the above prior art, even if the tip of the electrode of the lamp, which is a high pressure discharge lamp, is consumed over time (the lamp voltage increases), it is necessary to control the brightness of the lamp to be constant. For this purpose, a power control circuit 25 that constantly controls the power supplied to the lamp is indispensable. The multiplier 16 which is the center of the control is integrated into an IC, but the circuit configuration is complicated, and a negative power source (−12 V or the like) is required, and the current is converted to LOG using the characteristics of the transistor—inverse LOG. In order to perform conversion, each transistor has a variation, and it is necessary to select the transistor, which is expensive.

  The present invention solves the above-mentioned conventional problems, and the power control circuit of the high pressure discharge lamp lighting device incorporates the lamp current 56 into the differential amplifier by the level shift circuit and the four switching elements of the AC conversion circuit 51. The power loss due to is corrected. With a simple circuit configuration, low-cost and high-precision lamp brightness is constant, high-voltage lighting equipment that stabilizes control and electronic equipment using it are reduced in size, and the performance and life of the lamp are extended. It is the purpose.

  In order to achieve the above object, the present invention has the following configuration.

  The invention according to claim 1 of the present invention is a DC-DC converter or an AC-DC converter that supplies power to a high-pressure discharge lamp (AC lamp), and converts the output of the converter into the AC lamp current to convert the AC. An AC converter circuit to be supplied to the lamp, and a first voltage for voltage-converting an AC lamp current detection voltage obtained by voltage-converting a current flowing through the AC lamp to a polarity side of a reference power supply and connecting the voltage to one of the inputs of the differential amplifier. A level shift circuit and a second level shift circuit from the reference power source are connected to the other input of the differential amplifier, and a voltage proportional to the converter output voltage is converted into a current source of the differential amplifier. A comparator that compares a voltage converted from the current output of the differential amplifier with a reference voltage, and the DC-DC converter or AC converter by the comparator output. -A high pressure discharge lamp device comprising means for controlling the output of a DC converter and means for correcting the power of the high pressure discharge lamp to be constant, and with a simple circuit configuration, the lamp brightness is made constant with high accuracy while being inexpensive. Thus, the effect of stabilizing the control can be obtained.

  The invention according to claim 2 of the present invention is a means for correcting the power of the high-pressure discharge lamp to be constant, and the AC lamp current detection voltage is shifted to the polarity side of the reference power supply to shift one of the inputs of the differential amplifier. A first resistor for correcting power is inserted into the first level shift circuit connected to the second level shift circuit, or the second level shift circuit from the reference power supply is corrected to the second at the other input of the differential amplifier. The high-pressure discharge lamp apparatus according to claim 1, further comprising a means for inserting the resistor, and has an effect of making the brightness of the lamp constant with high accuracy while being inexpensive with a simple circuit configuration.

  According to a third aspect of the present invention, there is provided a DC-DC converter or an AC-DC converter that supplies power to a high-pressure discharge lamp (AC lamp), and an output of the converter is converted to the AC lamp current to convert the AC. AC converter circuit supplied to the lamp, and AC lamp current detection voltage obtained by voltage-converting the current flowing in the AC lamp is shifted to the polarity side of the reference power supply by a voltage level with a resistor and a diode and connected to one of the inputs of the differential amplifier And a third level shift circuit connected to the other input of the differential amplifier from the reference power supply by a diode and a resistor to convert a voltage proportional to the converter output voltage into a current. A comparator that compares a voltage obtained by converting the current output of the differential amplifier with a reference voltage as a current source of a dynamic amplifier; A high-pressure discharge lamp device comprising means for controlling the output of a current-DC converter or an AC-DC converter and means for correcting the power of the high-pressure discharge lamp to be constant, a third level shift circuit and a fourth level shift A diode in the circuit can be incorporated in an IC (integrated circuit) constituting a differential amplifier, and the number of parts can be reduced and the size can be reduced.

  According to a fourth aspect of the present invention, as means for correcting the power of the high-pressure discharge lamp to be constant, as a current source of the differential amplifier, a voltage proportional to the converter output voltage is used as a current source of the differential amplifier. A voltage obtained by subtracting the emitter voltage) is converted into a current source for the differential amplifier, a voltage obtained by converting the current output of the differential amplifier is compared with a reference voltage, and the DC- 4. The high pressure discharge lamp device according to claim 3, comprising means for controlling the output of the DC converter or the AC-DC converter, and has the effect of making the lamp brightness constant with high accuracy while having a simple circuit configuration and being inexpensive. It is done.

  According to a fifth aspect of the present invention, there is provided a DC-DC converter or an AC-DC converter that supplies power to a high-pressure discharge lamp (AC lamp), and an output of the converter is converted to the AC lamp current to convert the AC. A voltage level shift of the AC conversion circuit supplied to the lamp and the AC lamp current detection voltage obtained by converting the current flowing through the AC lamp to the polarity side of the reference power supply is shifted by the third resistor, the first diode, and the fourth resistor. A third level shift circuit connected to one of the inputs of the differential amplifier, and a fourth of the fourth resistor, the second diode, and the fifth resistor from the reference power source to the other input of the differential amplifier. The level shift circuit is connected, and a voltage proportional to the converter output voltage is converted into a current source of the differential amplifier, and the current output of the differential amplifier is converted into a voltage. A comparator for comparing the pressure and the reference voltage, means for controlling the output of the DC-DC converter or AC-DC converter by the output of the comparator, and a high-pressure discharge lamp device for correcting the power of the high-pressure discharge lamp to be constant. This makes it possible to improve the lamp lighting performance by using a signal that makes the lamp brightness more constant and more accurate and reduces lamp flicker when the lamp is turned on.

  In the present invention, the power control circuit of the high pressure discharge lamp lighting device takes in the lamp current into the differential amplifier by the level shift circuit and corrects the power loss due to the four switching elements of the AC conversion circuit 51. Low-cost, high-precision lighting device that stabilizes the brightness of the lamp with a simple circuit configuration and high accuracy, and the electronic equipment that uses the device can be reduced in size at low cost and the performance and life of the lamp can be extended. It plays.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In the description, the same parts as those in the prior art are denoted by the same reference numerals.

(Embodiment 1)
Hereinafter, the first and second aspects of the present invention will be described with respect to the first embodiment.

  FIG. 1 is a circuit configuration diagram of a high pressure discharge lamp lighting device according to the present invention, and FIG. 2 is an operation waveform diagram showing its operation.

  The high pressure discharge lamp lighting device of FIG. 1 is connected to a high pressure discharge lamp (AC lamp) 11 from a DC power source 1 through a DC-DC converter 50 and an AC conversion circuit 51 as described in the prior art. The DC-DC converter 50 converts the voltage of the DC power source 1 into a high-frequency voltage of several tens of kHz by a PWM control signal 15c from the control circuit 35, and smoothes it to obtain a lamp output voltage. The control circuit 35 varies the output current supplied to the high-pressure discharge lamp 11 according to the lamp voltage, and controls the lamp power to be constant.

  Here, in the control circuit 35 of the high pressure discharge lamp lighting device of the present invention, the AC lamp current flowing through the high pressure discharge lamp 11 flows through the FET 8 or FET 10 of the AC conversion circuit 51, and the AC lamp current detection resistor in the level shift circuit 30. The voltage generated at 23 is level-shifted (voltage: Vm) between the reference power supply 30f by the resistor 30a and the resistor 30b + the resistor 30e, and is input to the base of the transistor 35b constituting the differential amplifier S. A reference power source 30f is input to the base of the transistor 35a constituting the differential amplifier S, and an intersection voltage (level shift voltage: Vn) between the resistors 30c and 30d is input.

As a result, the AC lamp current (Ila) is detected by the detection resistor 23 and is amplified by the transistors 35b and 35a of the differential amplifier S. In order to reduce the resistance variation, the resistance values of the resistors 30a and 30c are set to R _30a = R _30c and the resistance values of the resistors 30b and 30d are set to R _30b = R _30d .

  When the converter output voltage 55 (approximately the voltage Vla of the discharge lamp 11) is divided by the resistors 55a and 55b, the impedance is reduced by the amplifier (buffer) 56 and the current is converted by the resistor 56a, the converter output voltage 55 is approximately proportional to the voltage Vla of the discharge lamp 11. A transistor 35i and a transistor 35j that form a current mirror from which current (Ivla) is obtained are used as a current source of the differential amplifier S. The transistor 56b connected to the output of the amplifier (buffer) 56 cancels the base-emitter voltage (about 0.7V) of the transistor 35i of the current mirror for current conversion.

Therefore, the collector current (Ic35b) of the transistor 35b and the collector current (Ic35a) of the transistor 35a, which are the outputs of the differential amplifier S, are ΔIc35a = −ΔIc35b = α × Ivla × Ila.

  The outputs of the current mirror transistors 35c and 35d are inverted by the current mirror transistors 35h and 35g and subtracted by the current mirror transistors 35e and 35f. As a result, the combined output of the transistor 35f and the transistor 35g flows to the resistor 36 (I36).

Therefore, I36 = ΔIc35a − (− ΔIc35b) = 2α × Ivla × Ila
Therefore, since the voltage (V36) generated in the resistor 36 is proportional to the product of the AC lamp current (Ila) and the voltage Vla of the discharge lamp 11, it is compared with the reference voltage 22 by the comparator 15, and the PWM control circuit 12 is output by its output. When controlled, the DC-DC converter 50 can supply constant power to the high-pressure discharge lamp (AC lamp) 11.

  Next, the resistor 30e, which is means for correcting the power in the level shift circuit 30 to be constant, will be described.

  FIG. 2 is a simulation of the lamp power consumption, which is the product of the AC lamp current (Ila) when the lamp voltage: Vla (converter output voltage 55) is changed from 40V to 130V.

At the same time, the characteristics of lamp power consumption when the resistance 30e in the level shift circuit 30 is changed to 0Ω, 20Ω, and 40Ω are shown. As the resistance value of the resistor 30e increases, the lamp power consumption decreases as the lamp voltage increases. This is due to the characteristics of the differential amplifier S shown in FIG. The lower diagram in FIG. 3 shows the input voltage (Vm−Vn) of the differential amplifier S. The upper diagram of FIG. 3 shows the characteristics of the collector current (Ic35b) of the transistor 35b and the collector current (Ic35a) of the transistor 35a. The collector current increases linearly as the input voltage (Vm−Vn) of the differential amplifier S increases. Without being expressed, _Ic35b = _Io / (1 + ^{eq (Vm-Vn) / kT} ). I _o is the current of the current source, q / k is a constant, and T is the temperature.

  Therefore, when the resistance 30e is changed to 0Ω, 20Ω, and 40Ω, the input voltage Vm of the differential amplifier A increases, and the input voltage (Vm−Vn) range of the differential amplifier S in the lower diagram of FIG. The operation range of the collector current (Ic35b) of the transistor 35b in the upper diagram of FIG. 3 is also moved from “A” to “B”. As a result, as shown in FIG. 2, when the resistance value of the resistor 30e is increased, the lamp power consumption decreases as the lamp voltage increases, and the lamp power consumption can be corrected to be constant. It becomes.

  In the above, the FET 7 and FET 10 or the FET 9 and FET 8 of the AC conversion circuit 51 through which an AC lamp current flows has a specific resistance (R0), and a power loss occurs. In FIG. 2, when the lamp voltage: Vla (converter output voltage 55) increases linearly, the AC lamp current (Ila) decreases in a reciprocal, and the power loss = Ila × R0 and a similar curve is drawn. As a result, when the resistance 30e is changed, the power loss curve and the output current curve of the differential amplifier S are canceled out, and correction can be made to keep the lamp power consumption constant.

  The current output of the control circuit 35 is converted into a voltage by the resistor 36. The slope signal 18 for reducing flicker that changes the brightness of the lamp is also added to the resistor 36, and the slope signal is easily superimposed on the lamp current. Is possible.

(Embodiment 2)
The second aspect of the present invention will be described below with reference to the second embodiment.

  FIG. 4 is a circuit configuration diagram of a high pressure discharge lamp lighting device according to the present invention, and FIGS. 5 and 6 are operation waveform diagrams showing the operation thereof.

  The high pressure discharge lamp lighting device of FIG. 4 is connected to the high pressure discharge lamp (AC lamp) 11 from the DC power source 1 through the DC-DC converter 50 and the AC conversion circuit 51 as described in the first embodiment. The DC-DC converter 50 converts the voltage of the DC power source 1 into a high-frequency voltage of several tens of kHz by a PWM control signal 15c from the control circuit 35, and smoothes it to obtain a lamp output voltage. The control circuit 35 varies the output current supplied to the high-pressure discharge lamp 11 according to the lamp voltage, and controls the lamp power to be constant.

  Here, the high-pressure discharge lamp lighting device of the present invention will be described with respect to the differential amplifier S of the control circuit 35 and the level shift circuit 30P which is an input circuit.

  The AC lamp current flowing through the high-pressure discharge lamp 11 flows through the FET 8 or FET 10 of the AC conversion circuit 51, a voltage generated in the AC lamp current detection resistor 23 is amplified by the amplifier 26, and level-shifted from the reference power supply 30f by the diode 30g. The resistor 30b is connected to the output of the amplifier 26. The intersection (Vm) of the diode 30g and the resistor 30b is input to the base of the transistor 35b of the differential amplifier S. The base of the transistor 35a that constitutes the differential amplifier S inputs a reference power source 30f to the intersection voltage (level shift voltage: Vn) of the diode 30h and the resistor 30d + the resistor 30e.

  When the converter output voltage 55 (approximately the voltage Vla of the discharge lamp 11) is divided by the resistors 55a and 55b, the impedance is reduced by the amplifier (buffer) 56 and the current is converted by the resistor 56a, the converter output voltage 55 is approximately proportional to the voltage Vla of the discharge lamp 11. A current (Ivla) is obtained, and a current mirror of the transistors 35 i and 35 j is used as a current source of the differential amplifier S.

  From the above configuration, the voltage generated in the AC lamp current detection resistor 23 is amplified by the amplifier 26, and the current (current) flows from the reference power supply 30f to the diode 30g via the resistor 30b, whereby the voltage (Vf) across the diode 30g changes. The current is amplified by the transistors 35b and 35a of the differential amplifier S, the current (Ivla) proportional to the voltage Vla of the discharge lamp 11 from the current source (transistors 35i and 35j) of the differential amplifier S is modulated, and the resistor 36 Thus, a current for controlling the electric power to be constant can be obtained.

  Here, claim 4 will be described.

  The operation waveform of FIG. 5 shows the differential input of the differential amplifier S by the output of the amplifier 26 of the AC lamp current detection resistor 23 when the current source (transistor 35i and transistor 35j) of the differential amplifier S has a constant current (for example, 400 μA). The voltage (Vm−Vn), the collector current (Icm) of the transistor 35b, and the collector current (Icn) of the transistor 35a are represented. As a result, the change in the collector current (Icm) is small with respect to the change in the differential input voltage (Vm−Vn). This is because the voltage (Vd) across the diode 30g does not increase even if the current flowing through the diode 30g increases.

From the equation ^: I = Is * e ^{q (Vd) / kT According} to Vd = kT / q × log (I / Is).

  FIG. 6 shows a simulation result of this result by controlling the lamp power consumption to be constant.

  4 is a diagram without transistor 35i correction. When transistor 35i is corrected, the transistor 56b is added to the output of the amplifier 56 to cancel the base-emitter voltage of the transistor 35i as shown in FIG. This is the case.

  In FIG. 6, the lamp power consumption without the transistor 35i correction is constant, but the lamp power consumption with the transistor 35i correction becomes lower as the AC lamp current increases (leftward in FIG. 6). It becomes control.

  In the above circuit, the diode 30g and the diode 30h are incorporated in the same IC (integrated circuit) as the transistors 35i and 35j, so that variations in parts are reduced and the number of points and cost can be reduced.

(Embodiment 3)
In the following, Embodiment 3 explains the invention described in claim 5 of the present invention.

  FIG. 7 is a circuit diagram of a high pressure discharge lamp lighting device according to the present invention.

  FIG. 7 is a circuit that modifies the level shift circuit 30P of the control circuit 35 in the circuit configuration diagram of the high pressure discharge lamp lighting device of FIG. 4 and inputs it to the differential amplifier S as a level shift circuit 30Q.

  That is, in FIG. 7, the level is shifted by the diode 30g and the diode 30h from the power source 35k of the differential amplifier S through the resistor 30i, and an optimum bias voltage is given to the transistors 35b and 35a that are the input terminals of the differential amplifier S. The level shift circuit 30Q and the resistor 30e are means for correcting the lamp power consumption to be constant.

  As a result, the reference power supply 30f in FIG. 4 can be omitted, and the diode 30g and the diode 30h in the above circuit are incorporated in the same IC (integrated circuit) as the transistors 35i and 35j. Therefore, the number of parts and the cost can be reduced.

  The present invention is suitable for a lighting device for applying a high-pressure pulse when starting a high-pressure discharge lamp such as a high-pressure mercury lamp or a metal halide lamp, and an electronic apparatus such as a data projector using the same.

1 is a circuit configuration diagram of an electronic device according to Embodiment 1 of the present invention. Operation waveform diagram of electronic device in Embodiment 1 of the present invention Operation Waveform Diagram of Differential Amplifier in Embodiment 1 of the Present Invention The circuit block diagram of the electronic device in Embodiment 2 of this invention Operation waveform diagram of differential amplifier in embodiment 2 of the present invention Operation Waveform Diagram of Electronic Device in Embodiment 2 of the Present Invention The circuit block diagram of the electronic device in Embodiment 3 of this invention Block diagram of electronic device in conventional example Circuit diagram of electronic equipment in conventional example

Explanation of symbols

1 DC power supply 2, 7, 8, 9, 10 Switching element 6 Igniter circuit 11 High-pressure discharge lamp (lamp)
15c PWM control signal 17 lighting waveform generation circuit 17a microcomputer 18c slope signal 24 rectangular wave signal 25, 35 control circuit 26, 56 amplifier 30, 30P, 30Q level shift circuit 50 DC-DC converter 51 AC conversion circuit 52 drive circuit

Claims (5)

A DC-DC converter or an AC-DC converter that supplies power to the high-pressure discharge lamp, an AC converter circuit that converts the output of the converter into the AC lamp current and supplies the AC lamp current, and a current flowing through the AC lamp. A voltage level-converted AC lamp current detection voltage is voltage level shifted to the polarity side of a reference power supply and connected to one of the inputs of the differential amplifier, and the reference is applied to the other input of the differential amplifier. A second level shift circuit from the power source is connected, and a voltage proportional to the converter output voltage is converted into a current source of the differential amplifier, and a voltage converted from the voltage output of the differential amplifier and a reference A comparator for comparing voltages, means for controlling the output of the DC-DC converter or AC-DC converter by the output of the comparator, and the High-pressure discharge lamp apparatus having a means for correcting the power of 圧放 lamp constant. The means for correcting the power of the high-pressure discharge lamp to a constant level corrects the power to the first level shift circuit that shifts the AC lamp current detection voltage to the polarity side of the reference power supply and connects it to one of the inputs of the differential amplifier. 2. A means for inserting a first resistor for correcting power, or a second resistor for correcting power in a second level shift circuit from the reference power supply to the other input of the differential amplifier. High pressure discharge lamp device. A DC-DC converter or an AC-DC converter that supplies power to the high-pressure discharge lamp, an AC converter circuit that converts the output of the converter into the AC lamp current and supplies the AC lamp current, and a current flowing through the AC lamp. A voltage level-converted AC lamp current detection voltage is voltage-shifted by a resistor and a diode to the polarity side of the reference power supply and connected to one of the inputs of the differential amplifier, and the input of the differential amplifier On the other hand, a fourth level shift circuit comprising a diode and a resistor is connected from the reference power source, a voltage proportional to the converter output voltage is converted into a current source of the differential amplifier, and the current output of the differential amplifier is a voltage. A comparator for comparing the converted voltage with a reference voltage, and the DC-DC converter or AC-DC converter depending on the output of the comparator; High-pressure discharge lamp apparatus having a means for correcting the power of said a means high-pressure discharge lamp for controlling the output of the constant. The means for correcting the power of the high-pressure discharge lamp to be constant is a current obtained by subtracting a constant voltage from a voltage proportional to the converter output voltage as a current source of the differential amplifier, and is used as a current source of the differential amplifier, 4. A comparator for comparing a voltage converted from a current output of a differential amplifier with a reference voltage, and means for controlling an output of the DC-DC converter or the AC-DC converter by the comparator output. High pressure discharge lamp device. A DC-DC converter or an AC-DC converter that supplies power to the high-pressure discharge lamp, an AC converter circuit that converts the output of the converter into the AC lamp current and supplies the AC lamp current, and a current flowing through the AC lamp. The voltage level of the AC lamp current detection voltage obtained by voltage conversion is shifted to the polarity side of the reference power source by the third resistor, the first diode, and the fourth resistor, and connected to one of the inputs of the differential amplifier. And a fourth level shift circuit comprising the fourth resistor, the second diode, and the fifth resistor from the reference power source to the other input of the circuit and the differential amplifier, and proportional to the converter output voltage A comparator that compares a voltage obtained by converting a voltage into a current source of the differential amplifier, compares the voltage output of the current output of the differential amplifier with a reference voltage, and the comparator output DC converter or an AC - - electronic apparatus having a high pressure discharge lamp device for correcting the power means and the high pressure discharge lamp for controlling the output of the DC converter to a constant the DC by.

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