JPH0896973A - Electronic lighting device for discharge lamp - Google Patents

Abstract

PURPOSE: To maintain the sinusoidal waveform of the current of an alternating current input power source, and to generate the stabilized luminance without generating the flicker in a discharge lamp. CONSTITUTION: An alternating current input power source is connected to input terminals U, V, and the current is converted to the pulsating current by a rectifying circuit 2 through a filter 1 for high frequency. This pulsating current is converted to the high frequency at about 100kHz by a step-up-and-down type converter circuit 3. Constant power direct current output is generated through a rectifying circuit of the secondary side of a transformer T. A switching element Q1 of the step-up-and-down type converter circuit 3 is controlled by a computing control circuit 6 so that the sinusoidal waveform of the input current is maintained and that the constant power output is obtained. This constant power direct current output is converted to the low frequency at about 100Hz-300Hz, and supplied to output terminals (u), (v). Stabilized luminance is obtained by connecting a discharge lamp 5 to the output terminals (u), (v).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic lighting device for a discharge lamp, in which a current drawn from an AC power supply is made sinusoidal and the electric power of the discharge lamp is controlled to stably light up.

[0002]

2. Description of the Related Art Most conventional lighting devices for discharge lamps use a magnetic leakage transformer. Power control is not performed, and when the input voltage changes, the power consumption of the discharge lamp also changes and the brightness changes, There is a problem such as affecting the life of the discharge lamp, and as shown in FIG. 9, the power consumption of the discharge lamp also changes according to the voltage change of the commercial voltage, which causes brightness ripples and causes flicker when used in a projection device. There was a problem that the image was difficult to see. In addition to the above-mentioned problems, the magnetic leakage transformer system is large and heavy and is inconvenient to carry. Therefore, in recent years, an electronic lighting device using a high frequency modulation system using a high speed switching element has begun to be used.

An example of a conventional electronic lighting device for a discharge lamp is shown in FIG.
Shown in. In this circuit, the AC voltage is rectified by the rectifier circuit 21,
When the input voltage is 100V system, SW1 is closed to double voltage rectification, and when it is 200V system, SW1 is opened to perform full-wave rectification to obtain DC voltage of about 270 to 330V, and the step-down chopper circuit 22 is used as a discharge lamp. Convert to the required voltage. The converted DC voltage is converted into switching elements Q2, Q5 and Q of the bridge circuit 23.
The conduction of 3 and Q4 is switched to generate a rectangular wave AC voltage, which is supplied to the discharge lamp. By operating the step-down chopper circuit 22 at high frequency, a small and lightweight ballast can be realized.

[0004]

However, in such a conventional electronic lighting device for a discharge lamp, a large amount of harmonic current is supplied to the distribution system in a waveform in which the input current flows only in a part of the electrical angle of the AC cycle. This caused an increase in power receiving and distribution capacity and harmonic interference. In addition, the harmonic regulations that are scheduled to be implemented soon cannot be satisfied, which is a serious problem in practice. In order to satisfy the harmonic regulation, it is necessary to use a harmonic suppressing means such as a step-up chopper in the preceding stage, but then, both the step-up chopper and the step-down chopper are required, which causes a problem that the cost is increased and the size is increased.

In the electronic lighting device for a discharge lamp, the present invention pays attention to such a problem and reduces the harmonics by making the input current sinusoidal, and at the same time, the discharge lamp as a load has a stable brightness without flicker. The task is to generate.

[0006]

In order to solve this problem, the present invention supplies a constant power to the output while suppressing harmonics in a buck-boost chopper circuit, and a low-frequency alternating current that does not flicker in a discharge lamp that is a load. It is controlled so as to supply constant power. First, the following means is proposed as the first basic means. A pair of input terminals connected to a commercial AC power supply, a rectifier circuit connected to the pair of input terminals for converting into a pulsating flow, and a step-up / down converter circuit connected to the pulsating flow output of the rectifying circuit, It consists of a switching element that switches at a frequency sufficiently higher than the frequency of this pulsating flow, a buck-boost inductance means, and a rectifier circuit, and turns off all the energy accumulated in the buck-boost inductance means during the ON period of the switch element. A step-up / down converter circuit that discharges to the output side during a period, an arithmetic control circuit that controls the output of the step-up / down converter circuit to keep constant power, and a constant frequency connected to the output of the step-up / down converter circuit. An inverter circuit for converting into an alternating voltage of, and a pair of output terminals connected to the output of this inverter circuit and supplying power to the discharge lamp Consisting of a discharge lamp electronic ballast device.

As a second means, in the arithmetic control circuit, the switching element of the step-up / step-down converter circuit is operated at a fixed frequency, and is operated at a fixed time ratio for at least one cycle of the commercial AC voltage. It is proposed that the duty ratio control of the switching element be performed so that the product of the average value of the output current and the output voltage value of the converter circuit becomes constant.

As a third means, in the arithmetic control circuit, the switching element of the step-up / down type converter circuit is operated at a fixed frequency, and is operated at a fixed time ratio for at least one cycle of the commercial AC voltage. To be inversely proportional to the average value of the input voltage of the converter circuit,
It is proposed to control the duty ratio of the switching element.

As a fourth means, in the arithmetic control circuit, the switching element of the step-up / down type converter circuit is operated at a fixed on-time, and is operated at a fixed time ratio for at least one cycle of the commercial AC voltage. It is proposed to control the operation cycle of the switch element in proportion to the square of the average value of the input voltage of the converter circuit.

As the fifth means, in the arithmetic control circuit, the switching element of the step-up / down converter circuit is operated at a fixed frequency, and the input voltage waveform of the step-up / down converter circuit is similar to the fluctuation of the average value of the input voltage. It is proposed that the stable and stable voltage is used as the current reference signal, and the switching element is turned off when the current of the switching element reaches the current reference signal.

As a sixth means, a series circuit of a resistor and a first capacitor is connected between the output terminals of the step-up / down converter circuit, and an inverter circuit is connected to the output of the first capacitor. It is proposed to connect a second capacitor and a load to the output of the circuit, provide the bridge circuit with means for detecting that a current has flowed, and short-circuit the resistor by the signal of the detection means. Is.

As a seventh means, it is proposed that the step-up / down converter circuit is provided with a correcting means for narrowing the conduction width of the switching element as the average value rises with respect to the fluctuation of the average value of the input voltage. To do.

As an eighth means, it is proposed that the buck-boost converter circuit is non-insulated. It should be noted that in the case of this non-insulated type, the input side and the output side are connected in direct current, but there is an advantage that the power transfer efficiency is higher than that when a transformer is used. is there.

As a ninth means, it is proposed that the buck-boost converter circuit is of an insulating type. In the case of this insulated type, the power transmission efficiency is slightly lower than that of the non-insulated type, but there is an advantage that the degree of freedom in setting the output voltage is widened.

[0015]

FIG. 1 shows a first embodiment of the present invention. The ballast has a filter and a starting circuit other than those shown in the figure, but they are omitted because they are not related to the constituent features of the present invention. A high frequency filter 1 is connected to the AC input terminals U and V, and a rectifier circuit 2 is connected to the output thereof. Rectifier circuit 2
The buck-boost converter circuit 3 is connected to the output of and the inverter circuit 4 is connected to the output. A discharge lamp 5 as a load is connected to the output of the inverter circuit. Then, the secondary current of the transformer T of the converter circuit is detected by the current transformer CT1, and the diode D2, the resistors R3 and R4, and the capacitor C3 are detected.
Is averaged and connected to one input terminal X of the multiplier MP1. The detected value of the output voltage of the step-up / down converter circuit detected by the resistors R1 and R2 is connected to the other input terminal Y. The output of the multiplier MP1 is connected to the non-inverting input terminal of the amplifier OA1 and the reference value Er1 is connected to the inverting input terminal of the amplifier. The output of the amplifier is connected to the output side control voltage Vcc2 through the photodiode of the photo coupler OC and the resistor R5. The phototransistor is connected to the input terminal of the pulse width modulation circuit (hereinafter referred to as the PWM circuit) of the control circuit 6. The other input terminal of the PWM circuit is connected to the oscillator circuit. The output of the PWM circuit is connected to the control terminal of the switching element Q1 of the buck-boost converter circuit 3 via the drive circuit 7.

Next, the operation of this embodiment will be described. The applicant has already applied for a method of suppressing harmonics using a buck-boost converter circuit (Japanese Patent Laid-Open No. 3-250753).
Therefore, a portion related to the present invention will be described. The pulsating current voltage obtained by full-wave rectifying the AC voltage is applied to the primary winding of the transformer T using the switching element Q1 and intermittently applied at a frequency much higher than the AC voltage (for example, 100 kHz). Energy is stored in the switch element, and all the stored energy is taken out during the off period of the switch element. Assuming that the switching period of the switch element is T, the duty ratio is Dr, the instantaneous value of the input voltage is ei, and the inductance value of the choke coil is L, the current peak value when the switch element is on is i (1)
It is represented by a formula. i = (ei * Dr * T) / L (1) T and L are constants, and assuming that Dr is constant for one cycle of the AC input voltage, the peak value i is proportional to the input voltage ei. The absolute value iav of the average value of the AC input current flowing during the period of one switching cycle is expressed by equation (2). iav = (ei * Dr < ² > * T) / 2L (2) The switching element has a fixed frequency (constant T) and a fixed time ratio (D).
When operated at a constant r), it can be seen from Equation (2) that the average current value of each switching cycle is proportional to the input voltage. The input current waveform, which is a continuous average value, has a similar shape to the input voltage waveform and does not include harmonic components. The duty ratio control of the converter operating in this way is performed by multiplying the product of the proportional values of the secondary current of the converter transformer and the output voltage (proportional value of the output power) so that the output power becomes constant.
The error is amplified by the amplifier OA1 so as to maintain the value at the reference voltage Er1, and the error signal is sent to the PWM circuit of the control circuit by the photocoupler OC to control the pulse width of the switch element Q1. By slowing the control speed so that it does not respond to the input frequency component appearing in the output of the converter,
One cycle period of the AC input voltage has the same duty ratio. It should be noted that the duty ratio is controlled with respect to the fluctuation of the average value of the AC input voltage, and constant power is supplied to the load side. Therefore, the input current can be made a sine wave and a constant power can be supplied to the output. The bridge-type inverter circuit 4 is connected to the output side of the converter operating in this way, and the switching element is operated at a constant conduction angle of about 180 ° at a low frequency of about 100 Hz to 300 Hz, so that the discharge lamp, which is a load, is operated. A constant-wave square-wave AC voltage can be supplied to.

Next, the operation of the inverter circuit 4 will be briefly described. By alternately turning on / off Q2 / Q5 and Q3 / Q4, the polarity of the output current of the converter is alternately switched and supplied to the output of the bridge circuit. In general, a discharge lamp has a large variation in voltage during lighting, a large change over time, and a small impedance at the time of lighting, and therefore cannot be stably lit by supplying a constant voltage or a constant current. As in the present embodiment, the electric power supplied to the load side is constant power, so that the discharge lamp can be stably turned on. In addition,
Control is possible even if current detection is performed by the output current of the inverter circuit 4, but because of the low frequency current, the current transformer for current detection becomes large and it is not a good idea.

[0018]

Second Embodiment FIG. 3 shows a second embodiment of the electronic lighting device for a discharge lamp according to the present invention. The main circuit is similar to that of the embodiment shown in FIG. Resistors R21 and R for the output of the rectifier circuit
22 and the capacitor C21 are connected to detect the average value, and the detected value is connected to the input of the inverse proportional circuit 8. The output of the inverse proportional circuit is connected to the input terminal of the PWM circuit of the control circuit 6. The other input terminal of the PWM circuit is connected to the oscillator circuit. The output of the PWM circuit is connected to the input of the drive circuit. The output of the drive circuit is connected to the controlled terminal of the switch element Q1 of the buck-boost converter circuit 3.

Next, the operation will be described. The switching element Q1 has a frequency much higher than the AC input voltage (for example, 100 kHz).
Is applied to the primary winding of the transformer T to store the energy, which is stored during the OFF period of the switch element. It is operated so that all the stored energy is extracted to the output side. In such a converter, as described in the first embodiment, the input current waveform can be made similar to the input voltage waveform by operating the switching element at a fixed frequency and a fixed duty ratio. No longer include. On the other hand, the energy amount Ej transmitted to the output in one cycle of the switch of the step-up / down converter in which the current is discharged to the secondary side in each cycle of the switch is expressed by the equation (3). Ej = (L · i ² ) / 2 (3) Regardless of the fluctuation of the average value of the input voltage, if there is no change in i at each phase of the AC input voltage, the energy transferred to the output The amount will not change. From the equation (1), i is proportional to ei.Dr. Therefore, if Dr is inversely proportional to ei, the output power becomes constant with respect to the fluctuation of the average value of the input voltage. Therefore, as in the embodiment of FIG.
To generate a voltage that is inversely proportional to the average value of the input voltage.
If the M circuit converts the pulse width into a pulse width according to the inverse proportional signal and drives the switch element with this pulse width signal, constant power can be supplied to the output even if the average value of the input voltage changes. If the resistance R21 >> R22, the proportional value of the average value of the input voltage can be obtained at both ends of the capacitor C21. A PWM circuit can easily convert a pulse width into a pulse width according to an inverse proportional signal by using a triangular wave. Further, by making the duty ratio Dr inversely proportional to the average value of the input voltage, the duty ratio becomes constant with respect to the change (periodic change) of the AC input voltage due to the frequency.
The input current is a sine wave.

[0020]

[Third Embodiment] FIG. 4 shows a third embodiment of the electronic lighting device for a discharge lamp according to the present invention. The main circuit is similar to that of the embodiment shown in FIG. Resistors R21 and R2 for the output of the rectifier circuit
2. Connect the capacitor C21 to detect the average value, connect the detected value to the input of the squaring circuit 9, connect the output of the squaring circuit to the input of the voltage controlled oscillator VCO, and connect the output of the VCO to the monostable circuit 11 Connect to the input of. The output of the monostable circuit is connected to the input of the drive circuit 7, and the output is connected to the driven terminal of the switch element Q1 of the buck-boost converter circuit.

Next, the operation will be described. Switching the switching element Q1 at a frequency much higher than the AC voltage,
When the switch element is on, the pulsating current voltage obtained by full-wave rectifying the AC voltage is applied to the primary winding of the transformer T to store energy, and all the energy stored in the off period of the switch element is stored. Operate to take out. When the switch period of the switch element is T, the duty ratio is Dr, the instantaneous value of the input voltage is ei, and the inductance value of the primary winding is L, the average value i of the current flowing to the input when the switch element is turned on.
av is expressed by equation (2). In equation (2), if the on time of the switch is ton, it can be rewritten as equation (4). iav = (ei · ton ² ) / 2LT (4) (4) Multiplying ei by the equation gives the instantaneous value p of the input power (5)
It is represented by a formula. p = (ei ² · ton ² ) / 2LT (5) From equation (5), if ton is constant and the period T is proportional to the square of the average value of the input voltage, the input power becomes constant and the average of the input voltage becomes It can be understood that it is not affected by the fluctuation of the value.

In this embodiment, the square value of the average value of the input voltage is squared by the squaring circuit 9, and the oscillation cycle of the voltage controlled oscillator VCO is proportional to the square value of the average value. Since the cycle is the reciprocal of the frequency, the oscillation cycle of the VCO is 2 times the average value of the input voltage.
It will be inversely proportional to the square. By generating a pulse having a fixed pulse width by the monostable circuit for the oscillation signal of the VCO, it is possible to obtain a fixed pulse width that is not influenced by the frequency. The output of the monostable circuit is used as a drive signal by the drive circuit to drive the switch element of the converter circuit. Since the square circuit operates at the average value of the input voltage, the operating cycle of the switch element,
The pulse width is not affected by the voltage change (periodic change) due to the frequency of the AC input voltage, and has a fixed frequency and a fixed duty ratio. Therefore, the input current waveform becomes similar to the input voltage waveform, the harmonic component is not included, and the input power becomes constant. The input power is transferred to the discharge lamp of the load connected to the output of the inverter after subtracting the internal loss. Although the discharge lamp has variations in voltage and current, since there is no extreme difference, it can be said that there is almost no change in internal loss due to variations in the discharge lamp. Therefore, almost constant power is transmitted to the load. In addition, in order to obtain a signal proportional to the square of the input voltage, a proportional value of the input voltage may be input to the input terminals X and Y of the multiplier.

[0023]

[Fourth Embodiment] FIG. 5 shows a fourth embodiment of the electronic lighting device for a discharge lamp according to the present invention. Resistor R at the output of rectifier
21 and R22 and the capacitor C21 are connected to detect the average value voltage, and the resistors R41 and R42 detect the proportional value of the rectified voltage. Connect the detected value of the capacitor C21 to the inverse proportional circuit 8,
The output of the inversely proportional circuit and the voltage of R42 are multiplied by the multiplier MP4. The output of the multiplier and the detected value of the transformer primary winding current detected by the current transformer CT4 are connected to the non-inverting input and the inverting input of the comparator CL4, respectively. The output of the comparator and the output of the oscillator OSC are connected to the pulse width circuit.
The output of the pulse width circuit is connected to the drive circuit 7, and the output of the drive circuit is connected to the switching element Q of the buck-boost converter circuit 3.
1 to the driven terminal.

Next, the operation will be described. Switching element Q
1 is switched at a frequency much higher than the AC voltage, and when the switching element Q1 is turned on, the pulsating current voltage obtained by full-wave rectifying the AC voltage is applied to the primary winding of the transformer T to supply energy. In the buck-boost converter that operates to store and release all the energy stored in the OFF period of the switching element to the output side, the switching cycle of the switching element is T, the duty ratio is Dr, and the instantaneous value of the input voltage is ei, 1 If the inductance value of the next winding is L,
The peak value i of the current flowing to the input when the switching element is turned on is expressed by equation (1). On the other hand, the energy amount Ej stored in the ON period of the switching element is represented by the equation (3). From equation (3), if the ON period of the switching element is constant for one cycle of the input voltage and the current peak value of the ON period of the switching element is constant for each phase of the input voltage regardless of the average value of the input voltage, the input The power is constant regardless of the fluctuation of the average value of the input voltage.

In this embodiment, a voltage inversely proportional to the proportional value of the average value of the input voltage is produced by the inverse proportional circuit 8, and this inverse proportional voltage is multiplied by the proportional value of the input voltage (rectified voltage) by the multiplier MP4. k1 · ei × (1 / (k2 · e
Therefore, a voltage similar to the input voltage and not affected by the fluctuation of the average value of the input voltage appears at the output. The comparator CL4 compares the output voltage of the multiplier with the proportional value of the primary winding current of the transformer T detected by CT4. PW
The M circuit sends a high level output to the drive circuit 7 by a high level signal from the oscillator and a low level output from a low level signal from the comparator. The drive circuit drives the switch element Q1 according to the signal from the PWM circuit. The signs of the high level and the low level may be set to any values, and the switching element may be turned off when the voltage from the current transformer CT4 matches the voltage from the multiplier.
By moving the switching element Q1 in this way, the input current is made a sine wave and the input power is made constant. Below, the third
In the same manner as in the above embodiment, almost constant power is transmitted to the discharge lamp 5 of the load.

[0026]

[Fifth Embodiment] FIG. 6 is a fifth embodiment of an electronic lighting device for a discharge lamp according to the present invention. Transformer T4 at the input terminal
, And the secondary winding is connected to the synchronous oscillation circuit 12. The output of the synchronous oscillation circuit is connected to the input of the sine wave generation circuit 13. The other input terminal of the synchronous oscillation circuit 12 is connected to the output of the sine wave generating circuit 13 so that the AC input voltage and the output of the sine wave generating circuit 13 become a synchronized signal.
12 works. Output of sine wave generator 13 and transformer 1
The output of the current transformer CT4 that detects the next current is output to the comparator C.
L4 is connected to the non-inverting input terminal and the inverting input terminal, respectively, and the output is connected to the input of the pulse width generating circuit. PWM
The other input of the circuit is further connected to the output of the synchronous oscillation circuit 12. The output of the PWM circuit is connected to the drive circuit 7, and the output of the drive circuit 7 is connected to the control terminal of the switching element Q1.

To explain the operation, a voltage proportional to the AC input voltage is detected by the transformer T4, and the synchronous oscillation circuit 12 and the sine wave generating circuit 13 using a phase locked loop PLL or the like are proportional to the AC input voltage. In synchronization with the applied voltage, a similar waveform is generated, and this voltage is compared with the proportional value of the primary winding current of the transformer T detected by CT4 by the comparator CL4. The PWM circuit generates a drive signal for the switch element Q1 by the output of the comparator and the signal from the synchronous oscillation circuit 12. The drive circuit drives Q1 according to this signal.
Similar to the first embodiment, the high level and low level codes of the parer and the PWM circuit are arbitrarily selected, and the transformer C
When the voltage from T4 matches the voltage from the sine wave generation circuit, the switching element Q1 may be turned off. By moving the switching element Q1 in this way, the input current is made a sine wave and the input power is made constant. Hereinafter, similar to the third embodiment, almost constant power is transmitted to the discharge lamp 5 of the load.

[0028]

[Sixth Embodiment] FIG. 7 shows a sixth embodiment. Immediately before lighting the discharge lamp, a relatively high voltage of about 270 V is required, but the voltage immediately after lighting is as low as around 10 V.
Therefore, the energy accumulated in the large-capacity capacitor C1 connected to the converter output is rapidly released at the same time when the discharge lamp 5 is turned on. Therefore, an excessive current flows through the switching element in the inverter circuit 4, so that it is necessary to take measures such as using an element having a current capacity or more for passing the output current. Therefore, as shown in the figure, a large capacity capacitor C connected to the converter output is used.
By connecting a resistor and a small-capacity capacitor C4 after 1, and connecting the inverter circuit 4 to both ends of this small-capacity capacitor C4, the resistor R7 limits the flow of an excessive current immediately after the discharge lamp 5 is turned on. After the lighting of the discharge lamp 5, the resistor R7 is short-circuited at the contact rl of the relay RL. A thyristor, a triac, a transistor or the like may be used instead of the relay RL.

[0029]

[Seventh Embodiment] FIG. 8 shows a seventh embodiment. In the above description, the buck-boost converter circuit 3 has been described as an insulating type, but the same effect can be obtained with a non-insulating inverting chopper circuit using the choke coil L. FIG. 8 shows a circuit of the inverted chopper type. In the case of this non-insulated type, it must be noted that the input side and output side are connected in direct current, but the power transfer efficiency is higher than that of the insulated type embodiment using the transformer. There is an advantage of becoming higher.

[0030]

[Measures against Input Voltage Fluctuation] In the embodiment described above, since the input power is controlled to be constant, when the input voltage changes drastically, for example, in the case of the world wide specification that changes from 85V to 264 Vrms, the input voltage is changed according to the input voltage. The input current also changes greatly. Therefore, the loss on the input side changes and the power transmitted to the output also changes. To avoid this, the power transmitted to the output can be made constant by correcting the control according to the average value of the input power. Since the input current decreases as the input voltage increases, the loss also decreases. In the case of the embodiment shown in FIG. 3, when the average value of the input voltage rises, the pulse width may be made narrower than the rate of increase. As a simple method, it can be realized by changing the ratio of the resistance values of the resistors R21 and R22.
When the resistance value is R21 >> R22, an average value appears in the capacitor C21, and when the resistance values of the resistors R21 and R22 are brought close to each other, the detected value increases as the input voltage increases because the peak charge approaches. However, since the ratio of the loss difference between the minimum and maximum of the input voltage to the output power is about 2 to 4%, no large correction is necessary, and the resistors R21 and R22 may be slightly adjusted according to the circuit design conditions. Since the voltage of the capacitor C21 rises when the resistance values of the resistors R21 and R22 are adjusted, the voltage is divided by a resistor that does not affect R22 and sent to the inverse proportional circuit. The embodiment of FIGS. 4 and 5 is also the same. In the embodiment of FIG. 6, if an average value detection circuit for input voltage is newly provided and the average value of input voltage is appropriately added to the current detection circuit by CT4,
When the average voltage of the input rises, the detected current apparently becomes large and the pulse width becomes narrow. As a result, even if the average value of the input voltage rises and the loss on the primary side decreases, the amount of electric power transmitted to the output is kept constant. If the input voltage does not fluctuate much, no correction is necessary.

[0031]

As described above, according to the present invention, the electronic ballast of the high-intensity discharge lamp is configured so that the buck-boost chopper circuit operates in the current reset mode / fixed time ratio to obtain the input current. Is a sinusoidal wave, and a constant power is supplied to the output, and the bridge inverter in the subsequent stage is operated at a low frequency to supply a stable constant power to the discharge lamp that is the load. Compared to a ballast, the number of components is about the same, and the input current can be made sinusoidal to significantly reduce harmonics.

[Brief description of drawings]

FIG. 1 shows a first embodiment of an electronic lighting device for a discharge lamp according to the present invention.

FIG. 2 is a current waveform diagram for explaining the operation of the embodiment shown in FIG.

FIG. 3 shows a second embodiment of the electronic lighting device for a discharge lamp according to the present invention.

FIG. 4 shows a third embodiment of the electronic lighting device for a discharge lamp according to the present invention.

FIG. 5 shows a fourth embodiment of the electronic lighting device for a discharge lamp according to the present invention.

FIG. 6 shows a fifth embodiment of the electronic lighting device for a discharge lamp according to the present invention.

FIG. 7 shows a sixth embodiment of the electronic lighting device for a discharge lamp according to the present invention.

FIG. 8 shows a seventh embodiment of the electronic lighting device for a discharge lamp according to the present invention.

FIG. 9 is a waveform diagram of a discharge lamp current or the like.

FIG. 10 is an example of a conventional electronic lighting device for a discharge lamp.

[Explanation of symbols]

1 ... High frequency filter 2 ... Rectifier circuit 3 ... Buck-boost converter circuit 4 ... Inverter circuit 5 ... Discharge lamp 6 ... Arithmetic control circuit 7 ... Drive circuit 8 ... Inverse proportional circuit 9 ... Square circuit 10 ... Voltage controlled oscillator 11 ... Monostable Circuit 12 ... Synchronous oscillation circuit 13 ... Sine wave generation circuit 15 ...
Discharge lamp lighting confirmation circuit 16 ... Bridge / double voltage switching rectifier circuit CL4 ... Comparator CT, CT4 ... Current transformer
Er1 ... Reference voltage L ... Buck-boost inductance OA1 ... Amplifier MP
… Multiplier RL… Relay

Claims (9)

[Claims] 1. A pair of input terminals connected to a commercial AC power source, a rectifying circuit connected to the pair of input terminals for converting into a pulsating current, and a step-up / down converter connected to the pulsating current output of the rectifying circuit. A circuit, which is composed of a switching element that switches at a frequency sufficiently higher than the frequency of this pulsating flow, a step-up / step-down inductance means, and a rectifying circuit, and is accumulated in the step-up / step-down inductance means during the ON period of the switch element. The buck-boost converter circuit that releases all the stored energy to the output side during the off period, the operation control circuit that controls the output of the buck-boost converter circuit to keep constant power, and the output of the buck-boost converter circuit. Connected to the inverter circuit that converts to an alternating voltage with a constant frequency, and connected to the output of this inverter circuit to supply power to the discharge lamp. That it consists of a pair of output terminals discharge lamp electronic ballast device. 2. With respect to the arithmetic control circuit, the switching element of the step-up / down converter circuit is operated at a fixed frequency, and is operated at a fixed time ratio for at least one cycle of the commercial AC voltage. The electronic lighting device for a discharge lamp according to claim 1, wherein the duty ratio control of the switching element is performed so that the product of the average value of the output current and the output voltage value of the pressure converter circuit becomes constant. 3. In the operation control circuit, the switching element of the step-up / step-down converter circuit is operated at a fixed frequency, and is operated at a fixed time ratio for at least one cycle of the commercial AC voltage. The electronic lighting device for a discharge lamp according to claim 1, wherein the duty ratio control of the switching element is performed so as to be inversely proportional to the average value of the input voltage of the type converter circuit. 4. In the operation control circuit, the switching element of the step-up / step-down converter circuit is operated at a fixed ON time, and is operated at a fixed time ratio for at least one cycle of the commercial AC voltage. 2. The operation cycle of the switch element is controlled in proportion to the square of the average value of the input voltage of the converter circuit.
An electronic lighting device for a discharge lamp according to. 5. In the arithmetic control circuit, the switching element of the step-up / down type converter circuit is operated at a fixed frequency, and the input voltage waveform of the step-up / down type converter circuit is similar to the fluctuation of the average value of the input voltage. The electronic lighting device for a discharge lamp according to claim 1, wherein a stable voltage is used as a current reference signal, and the switching element is turned off when the current of the switching element reaches the current reference signal. 6. A series circuit of a resistor and a first capacitor is connected between the output terminals of the step-up / down converter circuit, and a bridge inverter circuit is connected to the output of the first capacitor. A second capacitor and a load are connected to the output of the bridge circuit, means for detecting that a current has flown is provided in the bridge circuit, and the resistor is short-circuited by the signal of the detecting means. Item 6. An electronic lighting device for a discharge lamp according to any one of items 1 to 5. 7. The step-up / down converter circuit is provided with a correction means for reducing the conduction width of the switching element as the average value rises with respect to fluctuations in the average value of the input voltage. The electronic lighting device for a discharge lamp according to claim 1 or claim 3. 8. The electronic lighting device for a discharge lamp according to claim 1, wherein the step-up / down converter circuit is a non-insulated type. 9. The electronic lighting device for a discharge lamp according to claim 1, wherein the step-up / down converter circuit is an insulating type.