JP3718911B2 - Discharge lamp lighting device - Google Patents

Description

[0001]
[Industrial application fields]
  The present invention relates to a discharge lamp lighting device that can stably discharge a discharge lamp by reducing a current limiting element.
[0002]
[Prior art]
  FIG. 38 shows a circuit diagram of a conventional example. This circuit switches a switch SW inserted between the lamp LP and the power source to a or b at high speed, and a DC power source DC having a voltage higher than the characteristic voltage of the lamp LP.₁And DC power supply DC having a voltage lower than the characteristic voltage of the lamp LP₂Are alternately used to control the lamp current within the set range and try to light it, and the current limiting element can be reduced. When a voltage higher than the characteristic voltage of the lamp is supplied, the lamp current increases, and when a voltage lower than the characteristic voltage of the lamp is supplied, the lamp current decreases. Therefore, by appropriately controlling the switch SW, the lamp current is reduced. It can be controlled. Hereinafter, the principle will be described.
[0003]
  Generally, a ballast (current limiting element) is required to light a lamp (discharge lamp). This is because the electrical characteristics of the lamp are negative (that is, it has a negative resistance). The relationship between the lamp current E and the current density J is generally given by:
      J = σE
  Here, σ is called conductivity, and in the case of a solid, it may be regarded as a constant. However, in the case of gas discharge, the conductivity is a function of electron density as shown in the following equation.
      σ = enμ
[0004]
  Here, e is a unit charge, n is an electron density, and μ is a mobility. Mobility μ is a function of electron temperature and pressure, but may be considered constant. From this, it can be seen that the current density (that is, the discharge current) is determined by the electron density inside the lamp and the electric field. Basically, the idea that when the lamp current (current density) is determined, the electron density and the electric field are determined as a result is the easiest to understand, and this is actually the case. In general, when the current is increased, the electron density increases, and the electric field does not change so much (actually changes slightly but is not as remarkable as the electron density). When the lamp is lit with a voltage source without a current limiting element, the electron density increases, resulting in an increase in current. As a result, overcurrent flows and various troubles occur. Since the increasing time constant is larger than the decreasing time constant, the electron density increases. In order to avoid this, the energy applied to the electrons must be changed by changing the applied electric field.
[0005]
  When connecting from a stable lighting state to a high voltage source, the current starts to increase, so the voltage is lowered. This needs to be reduced below the lamp characteristic voltage (sustain voltage). Then, the current starts to decrease, and then the voltage is increased. This needs to be raised above the lamp characteristic voltage (sustain voltage). Then, the current begins to increase again. Therefore, the voltage is lowered again. This needs to be reduced below the lamp characteristic voltage (sustain voltage). Thereafter, these operations are repeated. Thus, if the voltage is changed above and below the characteristic voltage line of the lamp, the lamp can be lit stably. The time when the current actually increases and decreases is 0. An order of several msec to several msec and an increase are considered to be about several μ to several tens μsec.
[0006]
  FIG. 39 is a circuit diagram of another conventional example. In this circuit, two AC power sources AC₁, AC₂And a voltage lower than the characteristic voltage of the lamp is always supplied to the lamp LP via the inductor L, and an alternating voltage is supplied via the capacitor C so as to be superposed on the voltage LP. In other words, a high voltage is supplied, and the amplitude is modulated to try to light stably. In each of the conventional examples, two voltage sources sandwiching the characteristic voltage of the lamp are provided, and these are alternately connected to make the current limiting element substantially smaller or eliminate the current limiting element. Is.
[0007]
[Problems to be solved by the invention]
  The above-described conventional example is based on the idea of using a main power supply (in particular, a lower voltage) having a fixed effective voltage value that is not controlled, so that it is difficult to cope with a wide range of output changes of the lamp. There are problems such as high radiation noise from the lamp due to distortion of the current waveform.
[0008]
[Means for Solving the Problems]
  According to the present invention, in order to solve the above problems,When a voltage higher than the characteristic voltage is supplied, the lamp current increases, and when a voltage lower than the characteristic voltage is supplied, the lamp current decreases, and a voltage value higher and lower than the characteristic voltage of the discharge lamp, And a power supply means for outputting an alternating voltage component in which the instantaneous voltage is continuous and changes in units of one cycle, the power supply means being more than the characteristic voltage of the discharge lamp. A first AC power supply having a high voltage value and the instantaneous voltage continuously fluctuating; a second AC power supply having a voltage value lower than the characteristic voltage of the discharge lamp and the instantaneous voltage continuously fluctuating; And switching means for connecting the first AC power source and the second AC power source to the discharge lamp at a zero cross point in one cycle unit and switching the discharge lamp so as to be stably lit.Discharge lamp lighting deviceIt is what. That meansUsing two voltage sources, one higher than the lamp's characteristic voltage and one lower than the lamp's characteristic voltage, switched in time division and connected to the lamp, the voltage value of each voltage source is variable, and its amplitude is loaded It modulates according to the state of. With the above configuration, the current-limiting element of the discharge lamp lighting device can be reduced to stably light the lamp, and it is possible to cope with a wide range of output changes and improve radiation noise.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
  Of the present inventionAssumption 1Schematic diagram of36Shown in In this circuit, the voltage source DC_ThreeAnd DC_FourThe voltage value is variable, and DC_ThreeTakes an effective voltage value higher than the characteristic voltage of the lamp, and DC_FourTakes an effective voltage value lower than the characteristic voltage of the lamp. These voltage sources DC_ThreeAnd DC_FourUsing the voltage source DC_ThreeWhen the lamp is connected, the lamp current increases, and when the set value is reached, switching is performed by the switch means SW, and the voltage source DC_FourWhen the lamp is connected, the lamp current decreases, and when it reaches the set value, the switch means SW is used to switch the current to the lamp LP by setting the connection time from the power source to the lamp. The switch means SW can control the increase / decrease of the lamp current within the set range. When increasing the current to the lamp, not only the ratio of the connection time (cycle number) of the higher voltage source is increased, but the power supply voltage is lowered as the current increases. Further, the lower voltage source may be changed to a lower one. Further, when reducing the current to the lamp, not only the connection time ratio of the higher voltage source is reduced, but also the power supply voltage is increased according to the decrease. Further, the lower voltage source may be changed to the higher one.
[0010]
  Thus, by making the voltage of the voltage source variable and connecting them alternately, for example, when the lamp current is increased, it becomes possible to reduce the difference voltage from the power supply voltage due to a decrease in the lamp characteristic voltage. It is possible to cope with a wide range of output changes while reducing the stress of the current, and to reduce the current limiting element. Where the voltage source DC_Three, DC_FourThe variable range may vary from a positive maximum value to a negative maximum value to supply an alternating current to the lamp.
[0011]
  Of the present inventionAssumption 2Schematic diagram of37Shown in In this circuit, the voltage value of the voltage source is variable with one polarity.Configuration 1 of 36The polarity is reversed by the polarity reversing switches Sa to Sd and the alternating current is supplied to the lamp LP. Again, the voltage source DC_Three, DC_FourFor example, when the lamp current is increased, it becomes possible to reduce the voltage difference from the power supply voltage due to a decrease in the lamp characteristic voltage. It can be made smaller.
[0012]
  Examples of the present invention1Schematic diagram of1Shown in In this circuit, the voltage source is a voltage variable AC power source, and the voltage source AC has a higher AC effective voltage value than the characteristic voltage of the lamp.₁And low voltage source AC₂Two voltage sources are used. Figure shows how effective voltage changesConfiguration 1 of 36The voltage source in the two regions is alternately switched and connected to the lamp, and an alternating current is supplied to the lamp.
[0013]
  Similarly, in this case, by making both voltage values variable, for example, when the lamp current is increased, it becomes possible to reduce the difference voltage from the power supply voltage due to a decrease in the lamp characteristic voltage, thereby reducing the stress on the lamp. It is possible to reduce the current limiting element while reducing it. Further, if the voltage source is a high frequency, the device can be further reduced in size.
[0014]
  Examples of the present invention2Schematic diagram of2The operation waveform diagram is shown in Fig.3Shown in The basic configuration of this embodiment is such that a plurality of unitized voltage sources can be freely connected in series by the control means 3 and connected to a lamp as a load, and combined with a filter circuit of an inductor Lf and a capacitor Cf. Thus, a sinusoidal current can be supplied. C as voltage source₁The number of capacitors connected in series is changed according to the required voltage using capacitors of ~ Cn. Each capacitor C₁Charging to .about.Cn is performed during a period when no discharge is performed.
[0015]
  Each unit of a plurality of unitized voltage sources is composed of one capacitor and a bridge circuit surrounding it. For example, capacitor C₁Switch means S against₁a ~ S₁Combine d to make one unit. The operation of the unit is capacitor C₁Switch means S when the positive pole is connected to the inductor Lf and the negative pole is connected to point B.₁a, S₁d, S₂c, S₂d, S_Threec, S_Threed,..., Snc, Snd are turned on, and others are turned off. When all capacitors are connected in series, all the switches with subscripts a and d are turned on and the others are turned off in each unit. In addition, when it is desired to supply a voltage having the opposite polarity to the lamp, all the switches with subscripts b and c are turned on in each unit, and the others are turned off. In this way, the number of power supplies connected in series can be changed, and a smooth alternating current can be supplied to the lamp LP by a filter circuit of a small inductor Lf and a capacitor Cf.
[0016]
  Figure3The case where there are five capacitors will be described with reference to the operation waveform diagram of FIG. Time t₀At time t, the lamp voltage Vz crosses zero.₁Switch means S until₁a, S₁d, S₂c, S₂d, S_Threec, S_Threed,..., Snc, Snd are turned on, and others are turned off. In this way, the capacitor C₁When is connected to the filter circuit, the current gradually increases. The following time t₂Switch means S until₁a, S₁d, S₂a, S₂d, S_Threec, S_Threed,..., Snc, Snd are turned on, and others are turned off. In this way, the capacitor C₁, C₂When is connected to the filter circuit, the current gradually increases. Further, the switch means S until time t3.₁a, S₁d, S₂a, S₂d, S_Threea, S_Threed,..., Snc, Snd are turned on, and others are turned off. In this way, the capacitor C₁, C₂, C_ThreeIs connected to the filter circuit, the current gradually increases. Similarly, time t_Four, T_FiveIf the number of capacitors to be connected is increased and the period between the respective times is set, the voltage waveform can be raised in a substantially sine wave shape. Time t₆~ T_TenThe number of capacitors to be connected is decreased until the time is decreased in a substantially sine wave shape.
[0017]
  Time t_TenFrom the reverse, the polarity of the capacitor is reversed and the negative waveform is created in the same way. For example, time t₁₁Switch means S until₁b, S₁c, S₂c, S₂d, S_Threec, S_Threed,..., Snc, Snd are turned on, and others are turned off. In this way, the capacitor C₁Is connected to the filter circuit with the opposite polarity to the previous one, the current gradually increases in the negative direction, and the waveform is created in the same manner as in the positive direction.
[0018]
  Time t₂₀A positive waveform is made from the above, but here, a case where three capacitors are connected in series is shown. The connection of the capacitors and the operation of the filter are the same as when there are five capacitors. In this case, a low peak voltage can be supplied.
[0019]
  In this way, it is possible to change the number of capacitors or voltage sources to be connected by controlling each switch means. For example, when the lamp current is detected and increased above a set value, it exceeds the characteristic voltage of the lamp. If the amplitude of the voltage source or the connection cycle is decreased, or if the amplitude of the voltage source lower than the characteristic voltage of the lamp is decreased or the connection cycle is increased, the control can be performed in a stable direction. Furthermore, increasing the operating frequency and increasing the rate of control based on the number of connection cycles will enable control in a state where the difference between the two voltage sources is small, and control that will extend the life of the lamp. It becomes possible.
[0020]
  In DC lighting, both the electron density and the electron temperature are constant with no temporal change, but when the frequency of the sine wave voltage is increased to a high frequency (sine wave of several kHz or more), the electron density changes little. However, the electron temperature follows sufficiently. The runaway current that occurs when the lamp is turned on with a voltage source is due to an increase in electron density, and the control concept is basically the same as in the case of direct current. Although the electron density does not change with time, the electron temperature changes with time, and there are time constants for increase and decrease for each instantaneous value of current. Both the time constants increase at large currents and decrease at small currents. However, from the viewpoint of control time, it is considered that the order is almost the same as direct current even at high frequencies.
[0021]
  Figure3V₁, V₂Indicates a characteristic voltage of the lamp, and a sine wave voltage exceeding the characteristic voltage and a sine wave voltage lower than the characteristic voltage can be supplied by appropriately switching the number of stages of the capacitors in series by controlling the switch. If the switching point is set to the zero-cross point, the waveform does not become extremely distorted, and the lamp current waveform can be controlled above and below the characteristic voltage while maintaining a sine wave shape, further reducing radiation current while minimizing the actual current limiting element. The discharge lamp can be turned on at a low level.
[0022]
  Examples of the present invention3Figure of operation waveform of4Shown in The circuit of this example is shown in the figure2And the characteristic voltage V of the lamp₁, V₂This shows a case where a plurality of sinusoidal voltage periods exceeding 2 are taken. As the number of sinusoidal voltage periods exceeding the characteristic voltage of the lamp continuously increases, the effective value of the lamp current increases. The higher the frequency of the supply voltage compared to the increase time constant of the lamp current, the easier it is to control the lamp current by the number of periods.
[0023]
  Figure4In (a), time t₁Thus, it is possible to switch to a sinusoidal voltage supply lower than the characteristic voltage of the lamp, and then supply a voltage higher than the characteristic voltage of the lamp again, so that the lamp current can be stably controlled by repeating this. In this case as well, the switching point is set at time t.₁If the zero cross point is set as shown above, the waveform will not be extremely distorted, and the lamp current waveform can be controlled above and below the characteristic voltage while maintaining a sine wave shape.
[0024]
  Also figure4In (b), the time t₁The peak value of the waveform changes smoothly in a sine wave shape and is controlled so as to go up and down the characteristic voltage of the lamp. As a result, the discharge lamp can be turned on while reducing the radiation noise while minimizing the current limiting element as much as possible.
[0025]
  Examples of the present invention4Schematic diagram of5Shown in The basic configuration of this example is shown in the figure.2In this circuit, the lamp current detecting means 2 is provided. For example, when the increase or decrease of the lamp current is detected and the lamp current increases from the set value, the number of capacitors in series is decreased or the number of power supply connection cycles higher than the characteristic voltage is decreased. Alternatively, control is performed to increase the number of power supply connection cycles lower than the characteristic voltage. Conversely, if the lamp current decreases below the set value, increase the number of capacitors in series, increase the number of power supply connection cycles higher than the characteristic voltage, or reduce the power supply voltage lower than the characteristic voltage. Control to reduce the number of connection cycles. For the conversion unit and control means,2This is the same as the circuit shown in FIG.
[0026]
  In this way, by using the detection means, a sinusoidal voltage exceeding the optimum characteristic voltage and a sinusoidal voltage less than the optimum characteristic voltage can be supplied, and the radiation current can be further reduced by making the current limiting element as small as possible. The discharge lamp can be turned on with low noise.
[0027]
  Examples of the present invention5Figure of operation waveform of6Shown in The circuit of this example is shown in the figure5And the characteristic voltage V of the lamp₁, V₂This shows a case where the number of sinusoidal voltage periods exceeding or the number of sinusoidal voltage periods falling below is taken continuously. Reduces the number of switching of sinusoidal voltage sources across the lamp's characteristic voltage per unit time, and provides smooth current control rather than supplying a large voltage difference to the lamp, further reducing radiation noise The discharge lamp can be turned on.
[0028]
  Examples of the present invention6Figure of operation waveform of7Shown in The circuit of this example is shown in the figure5And the characteristic voltage V of the lamp₁, V₂The number of sinusoidal voltage periods exceeding or less than the number of sinusoidal voltage periods is continuously taken, and the amplitude is continuously changed. As described above, by continuously changing the amplitude, smoother switching can be performed, and the discharge lamp can be turned on with further reduced radiation noise.
[0029]
  Examples of the present invention7Figure of operation waveform of8Shown in The circuit of this example is shown in the figure5And the characteristic voltage V of the lamp₁, V₂Since the amplitude is continuously changed while alternately switching between a sinusoidal voltage period exceeding and below a sinusoidal voltage period, switching can be performed more finely and smoothly, and radiation noise can be further reduced. The light can be turned on.
[0030]
  Examples of the present invention8Figure of operation waveform of9Shown in The circuit of this example is shown in the figure5And the characteristic voltage V of the lamp₁, V₂The number and amplitude of the sinusoidal voltage periods exceeding or below the sine wave voltage period are changed randomly.When the period of the sinusoidal current is close to the time constant of the increase / decrease of the lamp current and is long Controllability can be improved.
[0031]
  Examples of the present invention9Figure of operation waveform of10Shown in The circuit of this example is shown in the figure5And the characteristic voltage V of the lamp₁, V₂By controlling the number or amplitude of sinusoidal voltage periods exceeding, and fixing the number of sinusoidal voltage periods below, it is possible to simplify the circuit when the change range of the lamp current may be narrow. Is.
[0032]
  Examples of the present invention10Figure of operation waveform of11Shown in The circuit of this example is shown in the figure5And the characteristic voltage V of the lamp₁, V₂The number or amplitude of sinusoidal voltage periods that are less than or equal to is controlled, and the number of sinusoidal voltage periods that exceed is fixed.10As in the case of the above, it is possible to simplify the circuit when the change range of the lamp current may be narrow.
[0033]
  Examples of the present invention11Schematic diagram of12The operation waveform diagram is shown in Fig.13Shown in The circuit configuration of the present embodiment is a general resonance type inverter circuit 4, but the operation is different from a general one. Here, a two-stone current resonance type is taken as an example. In an inverter for lighting a discharge lamp, the operating frequency of the switching element is set to be higher than the self-resonant frequency of the resonance circuit including the load, and switching is performed by delaying the phase of the current waveform of the switching element to reduce switching loss. Yes.
[0034]
  Figure13In period t₀-T₁Then, the operating frequency of the switching element is brought close to the self-resonant frequency of the resonance circuit to increase the resonance energy and increase the energy to the lamp. Period t₁-T₂Then, the operating frequency of the switching element is kept away from the self-resonant frequency of the resonant circuit to reduce the resonance energy and to reduce the energy to the lamp. If power is supplied to the lamp alternately by using two power sources when the frequency is high and low, and the lamp current is controlled, the inductance value as that of the current limiting element is not required, and the device can be miniaturized. . Similarly, a one-stone voltage resonance type inverter can control the on-time of the switching element to substantially make two voltage sources, thereby enabling the same control.
[0035]
  Examples of the present invention12Schematic diagram of14The operation waveform diagram is shown in Fig.15Shown in Here, a two-stone current resonance type inverter circuit is taken as an example. DC power supply DC₆Switch means S₁, S₂Is connected to the switch means S₂At both ends of the inductor L₁And capacitor C_ThreeAre connected in parallel. Capacitor C_ThreeOn both ends of the capacitor C_FourA lamp LP is connected via As described above, the circuit configuration of the present embodiment is a general resonance type inverter circuit, but the operation is different from a general one.
[0036]
  Figure15At time t₁Switch means S₁Turns on and time t₂Switch means S₁Is off, switch means S₂Turns on and time t_ThreeSwitch means S₂When is turned off, the operating frequency is lowered to increase the resonance energy and increase the energy to the lamp. Time t_ThreeSwitch means S₁, S₂Are turned off, and energy that decreases with free vibration of the resonance circuit is supplied to the lamp LP. Time t₁Switch means S again₁When the lamp is turned on and the oscillating current is supplied to the lamp in this repetition, the power of the two ranges above and below the characteristic voltage of the lamp is supplied to the lamp and the lamp current is controlled. An inductance value is not required, and the apparatus can be miniaturized.
[0037]
  Examples of the present invention13Figure of operation waveform of16Shown in The circuit configuration of this example is shown in the figure.5It is the same. When changing the lamp current, for example, when reducing the lamp current, the number of connection cycles of the voltage source higher than the characteristic voltage of the lamp gradually decreases, and the number of connection cycles of the voltage source lower than the characteristic voltage of the lamp. The lamp current can be smoothly changed by gradually increasing. In this case, the discharge lamp can be turned on with further reduced radiation noise.
[0038]
  Examples of the present invention14Schematic diagram of17Shown in The circuit configuration of the present embodiment is obtained by replacing the two voltage variable power supplies so far with one voltage variable AC power supply. The detection means 2 detects the state of the lamp current and controls the amplitude in the same manner as described above. If the voltage of the voltage variable AC power supply Vac is controlled by means 3 to control the lamp current amplitude instantaneously and the lamp current waveform is made sinusoidal, the circuit configuration is simplified and the radiation noise is further reduced. The discharge lamp can be turned on.
[0039]
  Examples of the present invention15Figure of operation waveform of18Shown in The circuit of this example is shown in the figure17And the characteristic voltage V of the lamp₁, V₂When the number or amplitude of the sine wave voltage periods exceeding the sine wave voltage source is controlled and the number is further controlled, a certain period (one or more, for example, t shown in the figure) is controlled.₁-T₂In this case, the lamp current is controlled by deleting the period. Also in this case, the circuit can be simplified when the change range of the lamp current may be narrow.
[0040]
  Examples of the present invention16Figure of operation waveform of19Shown in The circuit of this example is shown in the figure5And the characteristic voltage V of the lamp₁, V₂Is used to control the number or amplitude of sinusoidal voltage cycles, and to control the number of voltage cycles below the characteristic voltage of the lamp. A period (one or more, eg t₁-T₂In this case, the lamp current is controlled by deleting the period. Also in this case, the circuit can be simplified when the change range of the lamp current may be narrow.
[0041]
  Examples of the present invention17Figure of operation waveform of20Shown in The circuit of this example is shown in the figure5And the characteristic voltage V of the lamp₁, V₂Using a sinusoidal voltage source exceeding and below a sinusoidal voltage source, the number or amplitude of the sinusoidal voltage period is controlled, and the frequency of the voltage source exceeding the lamp characteristic voltage is reduced below the lamp characteristic voltage. It is higher than the source frequency. In this embodiment, when the voltage of the power source that is lower than the characteristic voltage of the lamp is closer to the characteristic voltage of the lamp than the voltage of the power source that exceeds the characteristic voltage of the lamp, a circuit that is stable and easy to control or has a simple configuration. Can be provided.
[0042]
  Examples of the present invention18Figure of operation waveform of21Shown in The circuit of this example is shown in the figure5And the characteristic voltage V of the lamp₁, V₂Using a sinusoidal voltage source exceeding and below a sinusoidal voltage source, the number or amplitude of the sinusoidal voltage period is controlled, and the frequency of the voltage source exceeding the lamp characteristic voltage is reduced below the lamp characteristic voltage. It is lower than the frequency of the source. In this embodiment, when the voltage of the power source that exceeds the characteristic voltage of the lamp is closer to the characteristic voltage of the lamp than the voltage of the power source that is lower than the characteristic voltage of the lamp, a circuit that is stable and easy to control or has a simple configuration. Can be provided.
[0043]
  Examples of the present invention19Figure of operation waveform of22Shown in The circuit of this example is shown in the figure5And the characteristic voltage V of the lamp₁, V₂Control the number or amplitude of sinusoidal voltage cycles using a sinusoidal voltage source exceeding and below the sinusoidal voltage source, and at the time of dimming, exceed the characteristic voltage of the lamp at least as the degree of dimming increases The amplitude of the voltage source is higher and the number of voltage cycles is controlled to be smaller. In this embodiment, the characteristic voltage of the lamp is V during dimming.₁, V₂To V₁', V₂This corresponds to the gradual increase in ', and more stable dimming lighting can be provided.
[0044]
  Examples of the present invention20Figure of block diagram23Figure shows the operation waveform.24Shown in In this embodiment, from an AC power supply, an input circuit 5 having an input protection circuit and a filter, for example, FIG.2Energy is supplied to the lamp LP through the main circuit 1 having the circuit shown in FIG. A detecting means 2 is provided between the lamp LP and the main circuit 1 to detect the current of the lamp LP and feed back to the control circuit 3 for control.
[0045]
  In this example, the figure24As shown in FIG. 2, during the preheating, a preheating current set to the filament of the lamp is supplied, and a voltage set to both ends of the lamp is supplied at the time of starting, and the lamp starts and lights up through preheating. From here, the main circuit is controlled by the detection signal from the detection means according to the lamp characteristic voltage Vla, and the voltage above and below the lamp characteristic voltage Vla is supplied to the lamp. When the lamp is preheated and started, it is not necessary to perform control according to the characteristic voltage Vla of the lamp. Therefore, if the operation is performed without feedback control, the control circuit can be simplified and a low-cost circuit is provided. It is something that can be done.
[0046]
  Examples of the present invention21Figure of block diagram25Fig.26Figure shows the operation waveform.27Shown in In the present embodiment, a capacitor is connected in parallel from an AC power source AC and charged, and is connected in series to a lamp for discharging. A polarity inversion means 14 is provided for AC conversion. Figure26As shown in FIG. 5, there are a plurality (1 to n) of boosting means 10 for parallel charging and series discharging, and it is possible to improve distortion of the input current by switching and connecting in accordance with the input voltage. Moreover, by outputting in order also at the time of output, output at an arbitrary frequency is possible.
[0047]
  Each boosting means can output voltages in two states, high voltage output and low voltage output, and can create an arbitrary boost ratio by changing the number of connected capacitors during charging and discharging. The figure27As shown in FIG. 6, it is possible to deal with two AC voltages that take values above and below the lamp characteristic voltage Vla. In this case as well, a lighting device with less noise can be realized by connecting a sinusoidal AC voltage source.
[0048]
  Examples of the present invention22Figure of block diagram28Shown in In this embodiment, the embodiment21As compared with the above, the boosting means 11 and 12 are constituted by two types for high voltage and low voltage. In operation, the figure24In the same way, the voltage higher and lower than the characteristic voltage of the lamp are selected by the selection means 13, supplied to the polarity inversion means 14, and supplied to the lamp LP. Also in this case, there are a plurality of (1 to n) boosting means for parallel charging and series discharging, and it is possible to improve distortion of the input current by switching and connecting according to the input voltage. Since output is possible and an arbitrary step-up ratio can be created by changing the number of capacitors connected during charging and discharging, it is possible to cope with two alternating voltages that take values above and below the changing characteristic voltage Vla of the lamp. Is possible. In this case as well, a lighting device with less noise can be realized by connecting a sinusoidal AC voltage source.
[0049]
  Examples of the present invention23Figure of operation waveform of29Shown in In this embodiment, the embodiment19Compared to the lamp, the characteristic voltage Vla of the lamp during dimming₂Higher voltage Vp_ThreeIs the characteristic voltage Vla of the lamp in the steady state.₁Higher voltage Vp₁Higher than that of the lamp, and the characteristic voltage Vla of the lamp during dimming₂Lower voltage Vp_FourIs the characteristic voltage Vla of the lamp in the steady state.₁Lower voltage Vp₂The output voltage is controlled so as to be further lower than the above. As a result, the overall energy can be reduced and the lamp voltage can be increased, so that a wide range of stable dimming is possible.
[0050]
  Examples of the present invention24Schematic diagram of30Figure shows the operation waveform.31The figure32Shown in In this embodiment, a high-frequency AC voltage source B (amplitude Vb) and a lamp FL are connected in series to a DC power source DC via a DC-AC conversion circuit such as a full bridge circuit composed of switch elements S1 to S4. In the operation, when the DC power source DC has a voltage close to the lamp characteristic voltage Vla and the high frequency AC voltage source B has the same polarity as the power source, Vdc + Vb (> Vla) is applied to the lamp FL, and the lamp FL runs away. try to. When the high-frequency AC voltage source B has a polarity opposite to that of the power source, Vdc−Vb (<Vla) is applied, and the lamp FL tends to go out. By making the cycle of the high-frequency AC voltage source B shorter than the time constant of the lamp FL, binary control of the lamp voltage can be performed. In this embodiment, the basic frequency of the lamp lighting AC can be set independently of the time constant of binary control by the time constant of the lamp FL.
[0051]
  Examples of the present invention25The figure33Shown in In this embodiment, two voltage sources of the inverter circuit 22 are prepared in series, one of which is a voltage (V2) lower than the lamp characteristic voltage, and the other is the difference between the voltage higher and lower than the lamp characteristic voltage. In a circuit that generates two voltages for stably lighting the lamp FL by switching the switching elements SW1 and SW2, the lamp FL is preheated and started. Usually, these two voltages are in the vicinity of the lamp characteristic voltage, and V1 << V2. In this example, a cock croft circuit is used as the starting voltage generating circuit 21.
[0052]
  The circuit operation is as follows. First, the lamp filament is preheated by turning on the switching elements SW3, SW4, and SW5 from the state where all the switching elements are off. At the same time, the cockcroft circuit is charged by switching the switching elements SW2 and SW7. When charging of the cockcroft circuit and preheating of the filament of the lamp are completed, the switching elements SW1, SW3, SW4, SW5, and SW7 are turned off, the switching elements SW2 and SW6 are turned on, the starting voltage is applied, and the lamp FL is lit. When the lamp FL shifts to the normal lighting state, the lamp FL is stably lit by switching the switching elements SW1 and SW2. As described above, in this embodiment, the preheating and starting circuit of the lamp FL is shown. In the filament preheating, a low voltage source is used to suppress the current value, and a high voltage source is used to generate the starting voltage. Thereby, the current of lamp preheating can be reduced.
[0053]
  Examples of the present invention26The figure34The figure35Shown in In this embodiment, in a load circuit such as an inverter circuit, the lamp application voltage is changed by changing the time constant of resonance to achieve stable lighting. Thereby, a circuit can be simplified and an inexpensive lighting device can be provided. As an example, a full-bridge inverter circuit is shown. When the lamp is normally lit, the detector detects the lamp current and34Then, stable lighting of the lamp is achieved by turning on / off the switching element SW1. Also figure35In this example, the same effect can be obtained by turning on / off the switching element SW1 and turning on / off the switching element SW2.
[0054]
【The invention's effect】
  According to the present invention, it is possible to directly control the lamp current itself by using a voltage source, it is possible to configure a small device by reducing the current limiting element, and to cope with a wide range of lamp output changes, and The crest factor can be reduced, there is less stress on the lamp, and stable lighting is possible. Furthermore, since a sine-wave lamp current can be obtained, there is an effect that radiation noise can be reduced. Further, there is an effect that the device can be further downsized by increasing the frequency.
[Brief description of the drawings]
[Figure1Example of the present invention1FIG.
[Figure2Example of the present invention2FIG.
[Figure3Example of the present invention2FIG.
[Figure4Example of the present invention3FIG.
[Figure5Example of the present invention4FIG.
[Figure6Example of the present invention5FIG.
[Figure7Example of the present invention6FIG.
[Figure8Example of the present invention7FIG.
[Figure9Example of the present invention8FIG.
[Figure10Example of the present invention9FIG.
[Figure11Example of the present invention10FIG.
[Figure12Example of the present invention11FIG.
[Figure13Example of the present invention11FIG.
[Figure14Example of the present invention12FIG.
[Figure15Example of the present invention12FIG.
[Figure16Example of the present invention13FIG.
[Figure17Example of the present invention14FIG.
[Figure18Example of the present invention15FIG.
[Figure19Example of the present invention16FIG.
[Figure20Example of the present invention17FIG.
[Figure21Example of the present invention18FIG.
[Figure22Example of the present invention19FIG.
[Figure23Example of the present invention20FIG.
[Figure24Example of the present invention20FIG.
[Figure25Example of the present invention21FIG.
[Figure26Example of the present invention21It is a circuit diagram for explanation of the operation.
[Figure27Example of the present invention21FIG.
[Figure28Example of the present invention22FIG.
[Figure29Example of the present invention23FIG.
[Figure30Example of the present invention24FIG.
[Figure31Example of the present invention24FIG.
[Figure32Example of the present invention24It is an operation | movement waveform diagram which shows these output waveforms.
[Figure33Example of the present invention25FIG.
[Figure34Example of the present invention26FIG.
[Figure35Example of the present invention26FIG. 6 is a circuit diagram showing another configuration of the load circuit.
[Figure36] Of the present inventionAssumption 1FIG.
[Figure37] Of the present inventionAssumption 2FIG.
FIG. 38 is a circuit diagram of a first conventional example.
FIG. 39 is a circuit diagram of a second conventional example.
[Explanation of symbols]
  AC ₁      Voltage source on the high voltage side
  AC ₂      Low voltage side voltage source
  SW switch means
  LP lamp

Claims (19)

When a voltage higher than the characteristic voltage is supplied, the lamp current increases, and when a voltage lower than the characteristic voltage is supplied, the lamp current decreases, and a voltage value higher and lower than the characteristic voltage of the discharge lamp, And a power supply means for outputting an alternating voltage component in which the instantaneous voltage is continuous and changes in units of one cycle , the power supply means being more than the characteristic voltage of the discharge lamp. A first AC power supply having a high voltage value and the instantaneous voltage continuously fluctuating; a second AC power supply having a voltage value lower than the characteristic voltage of the discharge lamp and the instantaneous voltage continuously fluctuating; A discharge lamp lighting device comprising switching means for connecting the first AC power source and the second AC power source to the discharge lamp at a zero cross point in units of one cycle and switching the discharge lamp to be stably lit. 2. The discharge lamp lighting device according to claim 1 , wherein the power supply means is configured to control a lamp current by changing an amplitude of a voltage waveform in one cycle unit. The power supply means has the first AC power supply having a voltage cycle in which the amplitude of the voltage waveform in one cycle unit changes in a substantially sine wave shape, and the voltage cycle in which the amplitude of the voltage waveform in one cycle unit changes in a substantially sine wave shape. The discharge lamp lighting device of Claim 2 provided with the said 2nd alternating current power supply. The discharge lamp lighting device according to claim 3 , wherein the power supply means is configured to control a lamp current by changing an amplitude of a voltage waveform at 1 kHz or more. 4. The discharge lamp lighting device according to claim 3, wherein the power supply means is configured to control the lamp current smoothly by continuously changing the amplitude of the voltage waveform in units of one cycle. The discharge lamp lighting device according to claim 3 , wherein the power supply means includes the first AC power source having a plurality of cycles and the second AC power source having a plurality of cycles. The discharge lamp lighting device according to claim 3 , wherein the power supply means is configured to alternately switch between the first AC power supply and the second AC power supply and to connect to the discharge lamp. The discharge lamp lighting device according to claim 3 , wherein the power supply means is configured to switch between the first AC power supply and the second AC power supply at random, and to connect to the discharge lamp. The discharge lamp lighting device according to claim 3 , wherein the power source means is configured such that at least one of the cycle with the first AC power source or the second AC power source is constant. Said power supply means, the first AC power supply or between the second AC power supply, and gradually increasing the number of one of the cycles, release of claim 3 configured to gradually decrease the number of other cycles Electric light lighting device. 4. The discharge lamp lighting device according to claim 3 , wherein the power supply means is configured to thin out at least one of the first AC power supply or the second AC power supply in units of cycles. The discharge lamp lighting device according to claim 3 , wherein the power source means is configured such that the first AC power source and the second AC power source have different frequencies. Said power supply means is adjusted to the extent that light during dimming becomes deeper, the first AC power source, a discharge lamp lighting apparatus according to claim 3 configured earthenware pots by reducing the number of cycles with a higher voltage peak value . It said power supply means is stable towards during startup of the first AC power source than when lighting the discharge lamp lighting apparatus according to claim 3 configured so you increase the voltage peak value. 14. The discharge lamp lighting device according to claim 13 , wherein the power supply means is configured to lower the voltage peak value of the second AC power supply as the light control during the light control becomes deeper . Claims configured to perform feedback control so that a voltage with a preset amplitude is supplied to the discharge lamp without performing feedback control during preheating / starting, and the lamp is stably lit by a detection circuit that detects the lamp current when lit. Item 1. A discharge lamp lighting device according to Item 1 . The power supply means includes the first AC power supply having a booster circuit made of a switched capacitor and a polarity inversion circuit for inverting the polarity of the output of the booster circuit, a booster circuit made of a switched capacitor, and the booster circuit The discharge lamp lighting device according to claim 1 , further comprising: the second AC power source having a polarity inverting circuit for inverting the polarity of the output of the first AC power source. 2. The discharge lamp lighting device according to claim 1 , wherein the power supply means is configured to superimpose a substantially rectangular wave-shaped AC voltage on the AC voltage component to output the discharge lamp in a stable manner. 3. 19. The discharge according to claim 18 , wherein the power supply means is configured to use one of a voltage value higher and a voltage value lower than a characteristic voltage of the discharge lamp for starting the discharge lamp and the other for preheating the filament of the discharge lamp. Electric light lighting device.

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