KR20240136753A - Drive circuit for high pressure discharge lamp - Google Patents

Abstract

The present invention is a high-frequency xenon lamp light that solves the problem of electromagnetic interference (EMI) caused by high-frequency surge.
The present invention relates to a driving circuit for a high-pressure discharge lamp that prevents flickering, comprising a rectifier and resonant circuit (200) and a first internal
By switching the first to fourth switching elements (Q1-Q4) under the control of the fourth switching control signal (G1-G4), the high frequency
An inverter section (400) that generates a wave signal, and an output side signal is fed back so that the power measured from the output side is small.
In case of political abnormality, the output power can be maintained constant by issuing a switching control signal (G1-G4).
The voltage and oscillation circuit (300) and the input AC power are rectified through bridge diode circuits (BD1-BD4).
A high-frequency rectifier (500) that converts the current into a high-frequency current to improve the power factor and supply a stable DC voltage to the lamp, and a high-frequency current
A high-frequency starting circuit (600) that performs one lamp preheating and a harmonic content pole that suppresses harmonic noise components
Including a digestion circuit (700), the inverter section (400) is composed of two pairs (four or more) of switching elements, thereby distributing the onion.
The driving circuit switches to the inverter section (400) in response to a control signal from the constant voltage and oscillation circuit section (300).
It is characterized by further including an IGBT power distribution circuit (300b) that generates a control signal (G1-G4).

Description

{DRIVE CIRCUIT FOR HIGH PRESSURE DISCHARGE LAMP}

The present invention relates to an electronic ballast for a high intensity discharge (HID) lamp, and more particularly to a xenon lamp.

The present invention relates to an electronic ballast for driving a high-voltage, high-current, high-pressure discharge lamp such as a lamp, at high frequency.

A typical electronic ballast includes a semiconductor element for starting in the ballast, and its switching action or electrode

The electrodes are preheated by a heating coil and the lamp is started by semiconductor switching action. During lighting, the lamp current and voltage are controlled.

A ballast used in a circuit in which the electrode is heated by a coil for polar heating, and is generated by its own LC resonant circuit.

There is a self-excited type that is true and a separate type that uses a separate generator.

General electronic ballasts have several advantages over conventional ballasts, but are vulnerable to voltage fluctuations and surge voltages.

There are several problems, so a protection circuit must be built in, and special measures must be taken when starting.

Meanwhile, general high-voltage discharge lamps have high voltage, such as mercury lamps, high-pressure sodium lamps, and metal halide lamps, and are tube-type.

The inside of the bulb becomes a high-temperature plasma state when lit. To create such high-voltage discharge conditions, recently

Electronic ballasts are mainly used, and PCT is disclosed as a self-excited electronic ballast for high-pressure discharge lamps.

There is something like WO99/51066.

First, let me explain the electronic ballast of the above public notice. The conventional HID electronic ballast is

It consists of a supply section, converter section, inverter section, output matching section, buffer DC power supply section, power control section, and gate transformer section.

However, among HID lamps, compared to general high-voltage discharge lamps that discharge at relatively low currents, night events and

Xenon lamps used as long-distance searchlights for landscape lighting or as military and marine searchlights are rated at 6 kV.

In addition, a high current flows momentarily when the light is turned on at a high voltage of 12kV. In addition, to eliminate the flickering phenomenon,

In order to generate high-frequency high voltage using a high-frequency starting circuit, surge current and high

Since it causes interference to other electronic equipment due to frequency interference, it actually causes interference with high frequency components and high voltages above a certain level.

And the generation of surge currents exceeding a certain level was prohibited. Ultimately, the interest in night events using searchlights was halved.

It had to be so.

In addition, it is used as a lighting up or night landscape lighting to illuminate the city's historical buildings or bridges.

For creating a beautiful city, or for special night lighting such as beautiful events or night broadcasts.

Since ultra-high voltage special lighting is required, it is difficult to generate high voltage power like the above with general commercial power (220V).

In order to do this, large, expensive transformers must be used, and a huge amount of power loss occurs, which is

This leads to the enlargement of the rectifier and an increase in its cost.

The inventors of the present invention have sought to solve the above problems and have developed a driving circuit for a high-pressure discharge lamp in the Republic of Korea.

The invention, similar to Patent No. 46630, is made, according to the driving circuit for the high-pressure discharge lamp, by first supplying commercial power

The converted DC is converted into a high-frequency oscillation pulse by a high-frequency oscillation circuit.

It is possible to generate high voltage and high current with only a small transformer by means of a high-frequency rectifier, and therefore it is small.

High-voltage discharge used as a searchlight that solves the problem of electromagnetic interference (EMI) due to high-frequency surge and high-efficiency

It was possible to provide a driving circuit for the lamp.

That is, when the above patented invention is described in detail with reference to Figure 1, the driving circuit for the high-pressure discharge lamp includes a power stabilization unit (100').

A rectifier and resonant circuit (200') that rectifies a rough input AC signal to supply a DC voltage, and a switching control signal (G1,

An inverter section that generates a high-frequency signal by switching the first and second switching elements (Q1, Q2) under the control of G2.

(400') and, when the output side signal is fed back and the power measured from the output side is greater than a predetermined value, the first

By controlling the switching of the first switching element and the second switching element, the output power is maintained constant.

and, when the lamp (900') is first turned on, the oscillation operation that starts switching the switching element is initiated.

The constant voltage and oscillation circuit (300') that allows the input AC power to be transmitted through bridge diode circuits (BD1-BD4).

A high-frequency rectifier (500') that converts the rectified direct current into a direct current to improve the power factor and supply a stable direct current voltage to the lamp,

A high-frequency starting circuit (600') that performs lamp preheating by high-frequency current, and suppresses harmonic noise components.

It is composed of a circuit section (700') for minimizing harmonic content and a rectifier protection circuit (800').

At this time, the inverter part (400') is controlled by the switching control signals G1 and G2 from the constant voltage and oscillation circuit (300').

The switching of the first and second transistors is performed at high frequency, so that the inverter section generates a high frequency signal.

all.

On the other hand, it is difficult to operate discharge lamps at a voltage higher than 48 V due to their characteristics, so they are operated at high powers of several kW or more.

In order to discharge, the driving current must be high, and therefore the cycle must be oscillated greatly. However,

In high-current systems, for frequencies above 8 kHz, shortwave distribution methods have limitations in completely eliminating flicker.

That is, the above-mentioned invention of the inventors of the present invention uses only a pair (two) of switching elements (Q1, Q2) to achieve a short-wave distribution method.

Because of its use, flickering often occurs at high frequencies above 8 kHz.

The present invention is to solve the problems of the prior art as described above, and the purpose of the present invention is to provide a device without a flicker phenomenon.

This also provides a driving circuit for a discharge lamp capable of oscillation at tens of kHz.

Additional purposes and effects of the present invention are described in detail below with reference to the attached drawings.

It will become clearer.

In order to achieve this purpose, the driving circuit for lighting a high-pressure discharge lamp according to the present invention is configured to input an AC signal.

A rectifier and resonant circuit (200) that supplies a DC voltage by rectifying the first to fourth switching control signals (G1, G2, G3, G4).

An inverter that generates a high-frequency signal by switching the first to fourth switching elements (Q1, Q2, Q3, Q4) under control.

(400); When the output side signal is fed back and the power measured from the output side is greater than a predetermined value, the first

By controlling the switching of the fourth switching element, the output power is constant by issuing the switching control signal (G1-G4).

It is to be maintained so that the oscillation operation that starts switching of the switching element is initiated when the lamp is first turned on.

A constant voltage and oscillation circuit (300) for oscillating; input AC power is supplied through bridge diode circuits (BD1-BD4).

A high-frequency rectifier (500) that converts the rectified direct current into a rectified direct current to improve the power factor and supply a stable direct current voltage to the lamp;

A high-frequency starting circuit (600) for performing lamp preheating by wave current; and a high-frequency starting circuit for performing suppression of harmonic noise components.

The circuit part (700) for minimizing the content of the wave is included, but the inverter part (400) is composed of two pairs (four) or more switching elements.

By being a saint, onion distribution is performed, and the driving circuit is controlled by a control signal from the constant voltage and oscillation circuit (300).

In response, the IGBT power distribution circuit (300b) that generates the switching control signal (G1-G4) to the inverter section (400) is further included.

It is characterized by containing.

As described above, according to the driving circuit for the high-pressure discharge lamp according to the present invention, the high-frequency rectifying driving circuit

High efficiency (more than 30% power consumption reduction and almost no power consumption at no-load) and lamp life is extended by 20%

It can extend the life of the lamp and completely prevent flickering, especially at high frequencies.

This is possible immediately and can maximize brightness when turned on, and the circuitry is adopted to minimize surge and radio interference.

It does not cause any adverse effects on other electronic equipment due to high-frequency interference, and is suitable for use as a searchlight for foreign events and military use.

Compared to the famous linear method (transformer method), the capacity and weight have been reduced to 1/3, and the xenon lamp is very close to natural light.

It has become possible to adopt a P-driven stabilizing electronic circuit.

Figure 1 is a circuit diagram of a conventional driving circuit for a high-pressure discharge lamp.
Figure 2 is a block diagram of a driving circuit for a high-pressure discharge lamp according to the present invention.
Figure 3 is a detailed circuit diagram of a driving circuit for a high-pressure discharge lamp according to the present invention.
<Explanation of symbols for major parts of the drawing>

Preferably, the harmonic content minimization circuit (700) is connected in parallel to both ends of the lamp electrode.

A capacitor (C4, C5) for absorbing voltage, a resistor (R6) and a varistor connected in parallel to both ends of the lamp electrodes

A high-frequency noise reduction circuit consisting of a parallel circuit of (ZNR2), and one side connected to the cathode terminal of the lamp is grounded.

A parallel circuit of a varistor (ZNR6) and a capacitor (C6), and one side of the varistor connected to the positive terminal of the lamp is grounded.

It consists of ZNR7.

More preferably, the high-frequency rectifier is composed of first to fourth bridge diodes (BD1-BD4), and each bridge

The first and second terminals of the diode are connected through resistors (R2-R5), respectively, and the first bridge diode (BD1)

The first terminal and the second terminal of the second bridge diode (BD2) and the second terminal and the fourth terminal of the third bridge diode (BD3)

The second terminal of the bridge diode (BD4) is interconnected, and the second terminal of the first bridge diode (BD1) and the third bridge

The first terminal of the diode (BD3) and the second terminal of the second bridge diode (BD2) and the fourth bridge diode (BD4)

The first terminals are interconnected, and also, the second terminal of the first bridge diode (BD1) and the fourth bridge diode (BD4)

The secondary side of the output side transformer (TR2) is connected to the first terminal, and the first terminal of the second bridge diode (BD2) is connected to

The (+) terminal of the lamp (900) and the first terminal of the fourth bridge diode (BD4) are connected directly through the waveform shaping element (TR3).

It is connected to the (-) terminal of the contact lamp (900).

The above high frequency starting circuit (600) has an input side connected to the + terminal (P21) and - terminal (P22) of the above high frequency rectifier (500).

The output side is connected to the momentary high-voltage induction coil (LC1) of the harmonic content minimization circuit (700), and one side input

The first input terminal is connected to the 5th high-frequency circuit through the start switch (SW1 or SW2), and the other input terminal is connected to the 5th high-frequency circuit through the RC parallel circuit (R7, C7, C8).

It is connected to the primary side of the PA transformer (TR5), and the secondary side of the fifth high-frequency transformer has a variable capacitor (VCT) connected in parallel.

And again, the harmonic content minimization circuit for starting the lamp through the series-connected capacitors (C9, C10, C11).

The moment of (700) is connected to the high-voltage induction coil (LC1).

Hereinafter, the optimal embodiment of the present invention will be described in detail with reference to the attached drawings, FIG. 2 and FIG. 3.

Figure 2 is a schematic block diagram of a driving circuit for a high-pressure discharge lamp according to the present invention, and Figure 3 is a detailed circuit diagram thereof.

As shown in FIGS. 2 and 3, the driving circuit for a high-pressure discharge lamp according to the present invention is largely divided into an input power supply unit.

(100), rectifier and resonant circuit (200), constant voltage and oscillation circuit (300), ARC inverter (400), high frequency rectifier (500),

The conventional circuit parts of the high-frequency starting circuit part (600), the harmonic content minimization circuit part (700) and the rectifier protection circuit part (800)

They all have the basics, but their detailed circuits are different.

In addition, the inverter part (400) of the present invention, unlike the inverter part (400') of the prior art, has two pairs (four) of switching elements (Q1, Q2,

Q3, Q4) are used, and these are four pairs of control signals generated at different times from the IGBT onion distribution circuit (300b).

Onion distribution is performed by a signal. Meanwhile, the high voltage of the ARC inverter unit (400) is forced to the high-frequency rectifier unit.

(500) converts a portion of the output of the high-frequency step-down unit (400a) into current and supplies it to the constant voltage and oscillation circuit unit (300).

A constant current conversion circuit (300a) for supplying pressure supplies an oscillation pulse to an IGBT full-wave distribution circuit (300b).

It is connected to the pressure and oscillation circuit (300).

The driving circuit for the high-pressure discharge lamp of the present invention will be described in more detail with reference to Fig. 3.

First, the input power supply unit (100) is for supplying stable power, like the input power supply unit (100') of Fig. 1.

However, in this embodiment, a no-fuse switch (NFB) is used to pass through a 200-240V transformer (TR1).

By doing so, the phase of the AC three-phase alternating current and phase voltage is kept constant, and the phase deviation, which is the voltage difference between phases, is maintained.

However, the present invention is not necessarily limited to three-phase AC as in this embodiment.

Next, the input stabilized AC power is rectified through the bridge diodes (D1-D6) of the rectifier and resonant circuit (200).

The above rectified voltage is smoothed by a diode (D2), a smoothing resistor (R1), and a capacitor (C7). In addition, one potential terminal of the capacitor is connected in series with a time constant compensation resistor (R1-1), so that the above rectified voltage is again smoothed by a noise filter.

It is desirable to filter by C12, C13.

The next stage, the onion distribution inverter part (400), is connected to the above noise filter circuit. Here, the resonant circuit

When configured as a RLC series-parallel resonant circuit, the amount of electrical energy radiated from the power source to the lamp is controlled, and the change

By maintaining large pulses stably, high-frequency surge characteristics and power factor are improved.

In particular, the inverter part (400) of the present invention is composed of a plurality of transistors (Q1, Q2, Q3, Q4) (for example, 4).

The first transistor (Q1) and the third transistor (Q3) are connected to the upper potential terminal (P11) and one side of the transformer (TR2).

The second transistor (Q2) and the fourth transistor (Q4) are inserted between the terminals (P13) and the other terminal of the transformer (TR2).

It is inserted between the self (P14) and the lower potential terminal (P12).

Between the source/drain terminals of the first transistor (Q1) to the fourth transistor (Q4), a reset diode (D7, D8,

D9, D10) are connected, and a capacitor (C2, C3) for maintaining constant voltage is connected between the upper potential terminal (P11) and the lower potential terminal (P12).

C3) is connected.

The above one-side and other-side terminals (P13, P14) naturally become the primary terminals of the output-side step-down transformer (TR2). In addition,

The gate terminals of the first to fourth transistors are supplied with a switching control signal (G1) from the constant voltage and oscillation circuit (300).

G2, G3, G4), and the emitter terminals of each of the above transistors are connected to a constant voltage and reset circuit (300).

The signal (E1, E2, E3, E4) is applied through the IGBT onion distribution circuit (300b).

The above high-frequency step-down unit (400a) is converted from DC 220 V to an inverter unit (400) by a voltage step-down output transformer (TR2).

The voltage size of the obtained high-frequency AC signal is reduced to a specified value (here 48 V) or less, taking into account the rated voltage of the lamp.

It will be released.

Meanwhile, the above-mentioned constant voltage and oscillation circuit (300) is supplied with the rectified DC voltage of the above-mentioned rectification and resonance circuit (200) as a power source.

It is driven by a driving power supply of, for example, 20 V and 8 V through an appropriate voltage divider resistor (not shown) inside, and the above

The secondary signal of the output transformer (TR2) of the high-frequency step-down unit (400a) is fed back and measured from the output side of the rectifier.

When the set power is higher than the specified value, the switching of the first to fourth transistors is performed at a high frequency (19 kHz to 37 kHz).

By controlling, the output power can be maintained constant.

In addition, when the lamp is first turned on, high-frequency starting is performed by a high-frequency starting circuit (600), which will be described in more detail below.

The order is as follows:

In other words, high-voltage discharge lamps require starting current, and in the past, high-voltage discharge lamps were started by a high-voltage current.

Due to the destruction of the furnace, it could not be used for moving lights of several kilometers, but according to the starting circuit of the present invention, it could be used for 1,500-

When starting a high-voltage discharge circuit with a lamp capacity of 12,000 V and a current of 1 mA to several mA,

It also has the effect of extending the lamp life and preventing circuit breakdown.

That is, when the xenon lamp is turned on, overvoltage and overcurrent are applied due to a transient phenomenon, which adversely affects the lamp blackening phenomenon.

It is necessary to preheat the lamp with a high-frequency current for about 0.05 to 0.8 seconds, and for this purpose, the high-frequency current of the present invention

The starting circuit adopts a circuit using an LC circuit and a hybrid IC to prevent blackening and thereby extend the life of the lamp.

Make it happen.

The input side of the high-frequency starting circuit (600) of the present invention may be connected to both terminals of the input power supply unit (100), but in this embodiment

In the example, it is connected to the + terminal (P21) and - terminal (P22) of the high-frequency rectifier (500), and the output side is connected to a circuit that minimizes harmonic content.

It is connected to the high-voltage induction coil (LC1) of the robot (700). In addition, one input terminal is a manual switch, which is a start switch.

(SW1) and relay automatic switch (SW2), and the other input terminal is the 5th high-voltage through RC parallel circuit (R7, C7, C8).

It is connected to the primary side of the high frequency transformer (TR5). The secondary side of the fifth high frequency transformer is connected in parallel with a variable capacitor (VCT).

And again, the harmonic content minimization circuit for starting the lamp through the series-connected capacitors (C9, C10, C11)

It is connected to the high-voltage induction coil (LC1) of the robot (700).

That is, a secondary variable capacitor is used for a lamp capacity that uses a high voltage of 1,500-12,000 V and a current of 1 mA to several mA.

The high voltage suitable for the lamp is adjusted in proportion to the gap force of the VCT and the induction coil recovery of the high-voltage induction coil (LC1).

Using a circle can extend the lamp life. For example, if the VCT's pole gap is 0.2mm, it will be 3500V, and if the VCT's pole gap is 0.2mm, it will be 3500V.

If the gap force of the VCT is 1 mm, 6500 V is applied to the lamp, and if the gap force of the VCT is 1.2 mm, 3500 V is applied to the lamp.

If the induction coil recovery is 2 times, the power supply is 7.3A at 9000V, and if the induction coil recovery of LC1 is 3 to 4 times,

A power of 2A at 3500 to 13000 V is supplied to the lamp.

Therefore, the power source including the high-frequency reflection component input through the input side first enters the RLC resonance including the parasitic inductor.

It is charged by absorbing the high frequency components reflected from the circuit (R7, C7, C8). When the capacitor is sufficiently charged,

It is boosted to high voltage in the third high frequency transformer (TR1). And at this time, when the start switch (SW1) is turned on,

When a large amount of current (for example, 140A) flows at once, the lamp (900) lights up, and after lighting up, the high-frequency starting circuit

is disconnected and high-voltage direct current from the high-frequency rectifier (500) is continuously supplied to the lamp. At this time, the schematic

The high frequency voltage value is determined by the number of turns of the high frequency transformer, but more fine adjustment is possible by using the variable capacitor (VCT).

It is done by adjustment of .

Meanwhile, according to the constant voltage and oscillation circuit (300) of the present invention, the rectified voltage, which fluctuates ±30V of the input voltage, is converted into a constant high frequency.

Since it is supplied as DC voltage to the ARC rectifier circuit, the output can be obtained evenly, which greatly extends the lamp life.

Therefore, the first to fourth circuits are controlled by the switching control signals (G1 to G4) from the constant voltage and oscillation circuit (300).

Since the switching of the transistors (Q1-Q4) is performed at high frequency, the inverter section generates a high frequency signal of 19 kHz to 37 kHz.

For example, when the ARC inverter unit (400) outputs AC of 19-37kHz and 800-1200V, a high-frequency

The step-down transformer (TR2) of the pressurized unit (400a) outputs the primary AC as a secondary AC of 28-42 V, 4-37 A. Furthermore, in the first half cycle, "upper potential terminal (P11) - first transistor (Q1) - step-down transformer (TR2) - fourth transformer

The current flows in the direction of "Gister (Q4) - lower potential terminal (P14)", and in the second half cycle, the current flows in the direction of "higher potential terminal (P14)".

Terminal (P11) - 3rd transistor (Q3) - step-down transformer (TR2) - 2nd transistor (Q2) - lower potential terminal (P14)"

Since the onion distribution is achieved by creating a current flow in the direction, flicker phenomenon occurs even at high frequencies.

It won't happen.

In addition, the secondary side of the output side transformer (TR2) is connected to a high-frequency rectifier (500). The high-frequency rectifier is composed of four bridges.

It consists of diodes (BD1-BD4). The first and second terminals of each bridge diode are connected to a varistor (ZNR1-

ZNR4) and resistors (R2-R5) are connected through a series circuit, and the first terminal of the first bridge diode (BD1) and the second bridge

The first terminal of the diode (BD2) is connected to the contact P23, and the second terminal and the fourth bridge of the third bridge diode (BD3)

The second terminal of the diode (BD4) is interconnected at the contact P24, and the second terminal and the third terminal of the first bridge diode (BD1)

The first terminal of the bridge diode (BD3) is connected to the contact P21, and the second terminal and the fourth terminal of the second bridge diode (BD2)

The first terminal of the bridge diode (BD4) is interconnected at the contact P22. Also, the second terminal of the first bridge diode (BD1)

The secondary side of the output side transformer (TR2) is connected to the first terminal of the terminal and the fourth bridge diode (BD4), respectively.

The first terminal of the 2-bridge diode (BD2) is connected to a harmonic content minimization circuit through a choke coil (TR3), which is a waveform shaping element.

(700) is connected to the (+) terminal of the lamp (900), which is one end of the second bridge diode (BD4).

It is connected to the (-) terminal of the lamp (900), which is the other end of the harmonic content minimization circuit (700), through a circuit (LC1).

The unexplained symbol CT1 is a current sensing element connected to the constant current conversion circuit (300a), and terminals P25 and P26 are circuit

A shunt contact intentionally formed to check the current from the outside.

To explain again, the constant current conversion circuit (300a) of the present invention adjusts the current to suit the high-voltage discharge lamp, and

The voltage and oscillation circuit (300) controls the frequency oscillation in an optimal state, and the IGBT full-wave distribution is performed in response to the oscillation signal.

The circuit section (300b) generates an optimal inverter (400) control signal (G1-G4) to drive the lamp at the optimal lamp driving voltage and current.

(900) to be organic.

Now, the high-frequency rectifier circuit (500) converts the input AC power into a DC that is rectified through bridge diode circuits.

It improves the power factor and supplies a stable DC voltage to the lamp. That is, it converts high-frequency AC 19-37kHz alternating current into high-frequency rectifier.

When passed through the high-speed diode bridge circuit of Ryubu (500), high frequency is included in pure DC and passes through the choke coil (TR3).

The waveform is formed while doing so.

On the other hand, a harmonic content minimization circuit (700) is connected to both ends of the above lamp. Harmonic content minimization circuit

(700) As seen in the lower right of Fig. 3, a capacitor (C4, C5) for absorbing the surge voltage is connected to the lamp anode.

is connected in parallel. That is, the reactor component of the output side transformer (TR2) and the resistance component (R2-) of the high-frequency rectifier (500)

The capacitors (C4, C5) along with R5) form a practical RLC resonant circuit, thereby effectively absorbing the surge component.

In addition, high-frequency noise is generated by a parallel circuit of a resistor (R6), a varistor (ZNR2), and a capacitor (C12).

A damping circuit is connected in parallel between the two electrodes of the lamp, and again, a varistor with one side grounded is connected to the cathode of the lamp.

(ZNR6) and a parallel circuit of capacitor (C16) are connected, and a varistor (ZNR6) with one side grounded is also connected to the positive terminal of the lamp.

Connected. That is, before the invention of the present inventors' driving circuit, the DMX 512 signal method was adopted for event lighting.

It has been recognized that it is still unusable due to interference with other devices caused by high-frequency surges.

The driving circuit for the high-pressure discharge lamp of the present invention has an EMI minimization circuit developed and built in to prevent radio interference containing high-frequency components.

By removing the harmonic content, the EMI problem is solved by reducing it to 0.8% or less, and it is also good for surrounding electronic precision devices.

It does not cause any adverse effects, and moreover, flickering does not occur even at high frequencies (over 8 kHz).

That is, the harmonic content minimization circuit (700) contains harmonic components in the DC component, and capacitors C4, C5 and

To minimize harmonic components in the Lister ZNR5 and eliminate EMI interference, capacitor C6 and varistor ZNR6 are used.

Use ZNR7 to allow harmonics to flow to ground.

Finally, regarding the rectifier protection circuit (800), the smoothing capacitor (C) of the rectifier and resonant circuit (200)

1) Input side information is received by measuring one side voltage of the noise filter (C12, C13) and one side voltage of the noise filter (C12, C13).

Receive power information from the secondary side of the transformer (TR4) connected to the power supply, and the rectifier detects abnormal oscillation or abnormal voltage.

In this case, the inverter unit (400) is activated by sending a gate control signal to the constant voltage and oscillation circuit unit (300).

The rectifier is protected by turning on/off the switching transistors (Q1-Q4). The rectifier protection circuit protects against overvoltage or

In addition to overcurrent, it is necessary to protect the rectifier from temperature abnormalities through a thermostat (not shown).

In addition, it is desirable to include a display driving circuit.

Above, the operation of the driving circuit for the high-pressure discharge lamp according to the present invention will be described. By the inverter circuit (400),

The high frequency voltage (e.g. 19 kHz to 37 kHz, 1.2 kV) generated here is rectified by a high frequency rectifier circuit (500) and converted into a DC power source.

At the same time, it is changed to a high voltage by the high-frequency starting circuit (600) and applied to the lamp, and at both ends of the lamp,

Before the lamp starts, it is in a state where a voltage of about 80 V is continuously applied, and by the start of the constant voltage and oscillation circuit,

At the moment when high-voltage discharge occurs in the lamp, high voltage of about 6-12 kV is applied to both ends of the lamp, resulting in a high voltage of about 5 kW.

This instantaneous discharge starts the lamp lighting. Once the lamp is lit, there is about 30 V across the two electrodes of the lamp.

The voltage is continuously applied, and at this time, a current of about 140 A flows between the two electrodes of the lamp.

Meanwhile, if the noise component such as surge is limited to less than 10% of the high-frequency power signal applied to the lamp, EMI

The problem is said to be solved, if the harmonic content minimization circuit (700) of the present invention is used, the noise

The content is limited to a maximum of 0.8%, making it possible to resolve EMI problems that adversely affect other electronic devices.

It works.

In addition, the flicker phenomenon can be prevented even at high frequencies by the onion distribution method. The present invention has been described above with reference to one embodiment shown in the attached drawings, but the present invention is not limited thereto.

Of course, various modifications are possible within the scope that can be easily conceived by those skilled in the art. Therefore,

The scope of the present invention should be limited only by the following claims.

Claims (1)

As a driving circuit for lighting a high-pressure discharge lamp,
A rectifier and resonant circuit (200) that rectifies an input AC signal and supplies a DC voltage;
The first to fourth switching elements (Q1, Q2, Q3,) are controlled by the first to fourth switching control signals (G1, G2, G3, G4).
Inverter section (400) that generates a high-frequency signal by switching Q4);
When the output side signal is fed back and the power measured from the output side is higher than a predetermined value, the first to fourth
By issuing the switching control signal (G1-G4) that controls the switching of the switching element, the output power is maintained constant.
and initiates the oscillation operation that starts switching the switching element when the lamp is first turned on.
is a constant voltage and oscillation circuit (300);
The input AC power is converted into a rectified DC through the bridge diode circuits (BD1-BD4) to improve the power factor.
A high-frequency rectifier (500) that supplies a stable direct current voltage to the lamp;
A high-frequency starting circuit (600) for preheating the lamp by high-frequency current; and
Including a harmonic content minimization circuit (700) that suppresses harmonic noise components,
The above inverter part (400) is composed of two or more pairs (four) of switching elements to perform onion distribution.
The above driving circuit responds to the control signal from the constant voltage and oscillation circuit unit (300) to the inverter unit (400).
A high-voltage circuit characterized by further including an IGBT power distribution circuit (300b) that generates a switching control signal (G1-G4).
Driver circuit for all lamps.