JP2005100829A - High pressure discharge lamp lighting device and lighting system using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high pressure discharge lamp capable of smoothly moving from glow discharge to arc discharge after lighting without increasing component stress or enlarging the size of a component. <P>SOLUTION: In this high pressure discharge lamp lighting device wherein a series circuit of a capacitor C1 connected with a lamp DL which is a load in parallel and an inductor L1 is connected between the junction of capacitors Ce1, Ce2, and the junction of switching elements Q1, Q2, and electric power of a low frequency square wave is provided to the lamp DL which is the load, an auxiliary chopper circuit 5 connected with the series circuit of the capacitors Ce1, Ce2 in parallel and comprising at least one inductor L3 and a switching element Q3 is provided, during the time of lighting and the time from lighting to arc discharge of the lamp DL only one of the switching elements Q1, Q2 is turned on/off at high frequency. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a high pressure discharge lamp lighting device for lighting a high pressure discharge lamp in a rectangular wave, and an illumination device using the same.

  FIG. 6 is a circuit diagram of a conventional high pressure discharge lamp lighting device. A series circuit of capacitors Ce1 and Ce2 and a series circuit of switching elements Q1 and Q2 are connected in parallel to the DC power supply BT. A series circuit of an inductor L1 and a capacitor C1 is connected between the connection point of the capacitors Ce1 and Ce2 and the connection point of the switching elements Q1 and Q2. A discharge lamp DL is connected to both ends of the capacitor C1 through a secondary winding of a pulse transformer PT of the igniter circuit 3. The discharge lamp DL is an HID lamp (high intensity high pressure discharge lamp). The switching elements Q1 and Q2 are made of MOSFETs and incorporate antiparallel diodes.

  The switching elements Q1 and Q2 are on / off controlled by the control circuit 1 as shown in FIG. In the first period T1, the switching element Q1 is turned on / off at a high frequency, and the switching element Q2 is turned off. In the second period T2, the switching element Q2 is turned on / off at a high frequency, and the switching element Q1 is turned off. The capacitors Ce1 and Ce2 have a sufficiently large capacity, and the voltage Vce1 of the capacitor Ce1 and the voltage Vce2 of the capacitor Ce2 do not fluctuate in the alternating period of the periods T1 and T2. The voltage Vbt of the DC power supply BT is divided by the capacitors Ce1 and Ce2 and Vbt = Vce1 + Vce2, but when the capacitances of the capacitors Ce1 and Ce2 are substantially equal, Vce1≈Vce2.

  When the switching element Q1 is turned on in the first period T1, a current flows through a path of the capacitor Ce1, the switching element Q1, the capacitor C1 (discharge lamp DL, igniter circuit 3), the inductor L1, and the capacitor Ce1. When the switching element Q1 is turned off, the current flows through the path of the inductor L1 → the capacitor Ce2 → the switching element Q2 (an antiparallel diode thereof) → the capacitor C1 (the discharge lamp DL and the igniter circuit 3) → the inductor L1 due to the energy stored in the inductor L1. . When the switching element Q2 is turned on in the second period T2, a current flows through the path of the capacitor Ce2, the inductor L1, the capacitor C1 (igniter circuit 3, discharge lamp DL), the switching element Q2, and the capacitor Ce2. When the switching element Q2 is turned off, the current flows in the path of inductor L1 → capacitor C1 (igniter circuit 3, discharge lamp DL) → switching element Q1 (an antiparallel diode) → capacitor Ce1 → inductor L1 due to the energy stored in the inductor L1. . Thereby, the voltage Vla of the discharge lamp DL becomes a low-frequency rectangular wave voltage as shown in FIG.

  The igniter circuit 3 generates a starting high voltage pulse voltage when the discharge lamp DL is not lit. FIG. 8 shows an operation waveform when the igniter circuit 3 operates and is not lit. When the discharge lamp DL is not lit, the amplitude of the lamp voltage Vla is Vbt / 2, a high voltage pulse voltage is superimposed on this, and the peak voltage is Vp. When the capacitances of the capacitors Ce1 and Ce2 are substantially equal, the positive and negative peak voltages are substantially equal.

  When the insulation of the discharge lamp DL is broken by the high voltage pulse voltage, the discharge lamp DL enters a glow discharge state, the igniter circuit 3 stops generating the high voltage pulse voltage, and the operation waveform of FIG. 7 is obtained. By continuing this state for a while, energy is injected into the discharge lamp DL, the discharge lamp DL shifts to an arc discharge state, and is in a stable lighting state. Such a conventional technique is disclosed in, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2000-195962).

FIG. 9 is an operation waveform diagram at the time of non-lighting when the capacitances of the capacitors Ce1 and Ce2 are unbalanced. Since the capacities of the capacitors Ce1 and Ce2 are different, the output voltage Vbt of the DC power supply BT is divided by the capacity ratio. Therefore, different voltages are applied to the discharge lamp DL in the periods T1 and T2 for each polarity of the low-frequency rectangular wave voltage. The voltage Vbt of the DC power supply BT is set so that the peak voltage Vp is about 250 V to 300 V or more required for starting the high-intensity discharge lamp DL in at least one polarity. The voltage dividing ratio of the capacitors Ce1 and Ce2 is also set so as to be a capacitance ratio that can apply about 250 V to 300 V in at least one polarity of the low frequency rectangular wave voltage. For example, when the output voltage Vbt of the DC power supply BT is 450V, the capacitance ratio of the capacitors Ce1 and Ce2 is set to 1: 2, and voltages of 300V and 150V are applied to the capacitors Ce1 and Ce2. Further, a low-frequency rectangular wave voltage having a voltage value of one polarity of 300 V and a voltage value of the other polarity of 150 V is applied to both ends of the high-intensity discharge lamp DL. In this example, as shown in the waveform of Vla in FIG. 9, Vce1 is 300V and Vce2 is 150V, and a sufficient voltage for starting is applied to the lamp in the period T1. Thereby, the withstand voltage of the capacitor Ce2 and the switching element Q2 can be lowered in the lighting device of FIG.
JP 2000-195962 A

  However, even if the operation as shown in FIG. 9 is used, if a half-wave discharge occurs when starting to turn on, current flows only in one direction with respect to the discharge lamp DL, so either one of the capacitors Ce1 and Ce2 On the other hand, 450 V, which is the output voltage Vbt of the DC power supply BT, may be applied, so that the stress of the parts is not reduced and the size is not reduced.

  The present invention has been made in view of these points, and is capable of performing a smooth transition from glow discharge to arc discharge after starting the lamp without increasing component stress and increasing the size of the component. An object is to provide a discharge lamp lighting device.

  According to the high pressure discharge lamp lighting device of the present invention, as shown in FIG. 1, a series circuit of a first capacitor Ce1 and a second capacitor Ce2, and a reverse conduction type first switching element, as shown in FIG. Q1 and a series circuit of the second switching element Q2 are connected in parallel, and between the connection point of the first capacitor Ce1 and the second capacitor Ce2 and the connection point of the first switching element Q1 and the second switching element Q2. A series circuit of a third capacitor C1 and a first inductor L1 connected in parallel to the lamp DL as a load is connected, and as shown in FIG. 7, the first switching element Q1 is operated at a high frequency in the first period T1. In the second period T2, the second switching element Q2 is turned on / off at a high frequency, so that the low-frequency rectangular wave power is supplied to the lamp DL as a load. In the high pressure discharge lamp lighting device to be supplied, an auxiliary chopper circuit 5 is provided which is connected in parallel to a series circuit of a first capacitor Ce1 and a second capacitor Ce2 and includes at least one inductor L3 and a switching element Q3. Only one of the first switching element Q1 and the second switching element Q2 is turned on / off at a high frequency in the time from the start of the lamp DL to the transition to arc discharge.

  According to the present invention, only one of the first switching element and the second switching element is turned on / off at a high frequency during the non-lighting time and the time from when the lamp starts to the transition to arc discharge. From the start of the high-pressure discharge lamp to the stable lighting, it can be prevented from falling into a half-wave discharge state. Further, by providing the auxiliary chopper circuit, it is possible to prevent the first capacitor or the second capacitor from being abnormally boosted even if only one of the switching elements is turned on / off.

  FIG. 1 is a circuit diagram of a high pressure discharge lamp lighting device according to the invention of claim 1. 6 is different from the conventional example of FIG. 6 in that an auxiliary chopper circuit 5 including a diode D1, a switching element Q3, and an inductor L3 is added. Further, the control signals given from the control circuit 1 to the switching elements Q1 to Q3 are different and have an operation waveform as shown in FIG. In other words, according to the present invention, only the switching element Q1 is turned on / off at a high frequency and the switching element Q2 is kept off at the time of non-lighting and the time when the lamp is started and reliably transits to arc discharge Thus, half-wave discharge is prevented by performing DC starting (DC voltage application).

  FIG. 2 is an operation waveform of each part from non-lighting to lighting. In the transition from the non-lighting state to the lighting state, when half-wave discharge occurs, current flows only in one direction with respect to the discharge lamp DL. However, when only the switching element Q1 is turned on / off, current flows only in one direction. Therefore, even if the extinction occurs, it is possible to prevent a half-wave discharge from occurring.

  As shown in the waveform of the lamp voltage Vla in FIG. 2, a period T3 of several tens of seconds to several minutes is provided in the period from the start of the lamp DL to the reliable transition to arc discharge, during which the switching element Q1 continues during non-lighting. The discharge is stabilized by turning on / off only, and thereafter, the switching element Q2 is also turned on / off in the same manner as in the prior art, and is switched alternately with the switching element Q1.

  During the period T3 during which the discharge is stabilized, while the switching element Q1 is on, the current I1 flows through the inductor L1 to the discharge lamp DL (capacitor C1), and energy is stored in the inductor L1. When the switching element Q1 is off, the energy stored in the inductor L1 is released, and a current I1 ′ flows to the discharge lamp DL (capacitor C1) through the capacitor Ce2, the parasitic diode of the switching element Q2, and the inductor L1. . At that time, the energy released from the capacitor Ce1 is applied to the capacitor Ce2.

  However, since only the switching element Q1 is driven in the period T3, there is no path for discharging the energy accumulated in the capacitor Ce2 when the DC starting is performed in the lighting device of FIG. 6, and thus the voltage is accumulated in the capacitor Ce2. It becomes. Therefore, in the circuit of FIG. 1, an auxiliary chopper circuit 5 as shown by a dotted line is provided to provide an energy discharge path for charging the capacitor Ce2.

By adding the auxiliary chopper circuit 5 as shown in FIG. 1, when the voltage stored in the capacitor Ce2 exceeds a predetermined value, the switching element Q3 is turned on, the energy charged in the capacitor Ce2 is discharged, and the switching element Q3 Through this, energy is stored in the inductor L3. Next, when the switching element Q3 is turned off, the energy stored in the inductor L3 is released, and the capacitor Ce1 is charged through the diode D1. At this time, the switching element Q3 is turned on / off at a high frequency. As a result, the energy accumulated in the capacitor Ce2 can be discharged, and overvoltage application can be prevented.
As described above, according to the configuration of claim 1 shown in FIGS. 1 and 2, there is an effect of preventing half-wave discharge and preventing overvoltage application.

  FIG. 3 is a circuit diagram of Embodiment 1 of the present invention. In the basic circuit shown in FIG. 1, since only the switching element Q1 is driven during the period from non-lighting to lighting, the drive circuit 2 needs to be a drive circuit using, for example, a drive transformer. However, when a drive transformer is used, problems such as an increase in the size of the parts occur. Therefore, a high voltage half-bridge driver IC (for example, IR2106) that is widely used in the market is used. In the case of such a driver IC 2a, the drive power supply of the high potential side switching element Q1 is generally charged when the low potential side switching element Q2 is turned on. Many bootstrap systems are used. That is, as shown in FIG. 3, when the switching element Q2 is turned on, the capacitor C3 is charged via the diode D3 from the drive power supply E1 of the low potential side switching element Q2, thereby driving the high potential side switching element Q1. Getting power.

  However, in the lighting device of the present invention, since only the high-potential side switching element Q1 is turned on / off, there is a problem that drive power cannot be supplied to the capacitor C3 via the diode D3. Therefore, as shown in FIG. 3, the inductor L3 is configured as a transformer, and after the capacitor Ce2 is discharged, the power for driving the switching element Q1 is supplied to the driver IC 2a in the drawing using the energy stored in the inductor L3. I was able to do that. Thereby, it becomes possible to continue switching even during the period from when the switching element Q1 shifts from non-lighting to lighting.

  However, since there is no power consumption at the load when not lit, the voltage Vce2 of the capacitor Ce2 does not increase from a constant value and the switching element Q3 does not turn on / off as shown in FIG. In the apparatus, as described above, the power for driving the switching element Q1 cannot be supplied to the driver IC 2a.

  Therefore, as shown in FIG. 3, a circuit for consuming energy stored in the capacitor Ce1 is provided at both ends of the capacitor Ce1. By installing a circuit used as an igniter as shown in FIG. 3 at both ends of the capacitor Ce1, power accumulated in the capacitor Ce1 can be consumed. The resistor R1, the capacitor C2, and the voltage response switch element S correspond to the pulse generation circuit 4 in FIG. When the capacitor C2 is charged from the capacitor Ce1 via the resistor R1 and the voltage of the capacitor C2 rises, the voltage response switch element S is turned on, and a pulse current flows through the primary winding of the pulse transformer PT. As a result, a high voltage corresponding to the turn ratio is generated in the secondary winding of the pulse transformer PT. When the voltage Vce1 of the capacitor Ce1 decreases, the output voltage Vbt of the DC power supply BT is constant, so that the voltage Vce2 of the capacitor Ce2 naturally increases. Thereby, since the switching element Q3 is turned on, the power for driving the switching element Q1 can be supplied to the driver IC 2a even when the lighting is not performed.

  FIG. 4 is a circuit diagram of Embodiment 2 of the present invention, in which a series circuit of a resistor R1 and a switching element Q4 is connected to both ends of a capacitor Ce1. Also in this case, the power stored in the capacitor Ce1 can be consumed by turning on the switching element Q4 as in the first embodiment. FIG. 5 shows an operation waveform of each part from non-lighting to lighting of the present embodiment, and the period during which the switching element Q4 is turned on is only during non-lighting. Therefore, no power is consumed by the resistor R1 during lighting. According to this embodiment, there is an effect that a power source for driving the switching element Q1 on the high potential side can be secured.

  The present invention can be used for office and general household lighting fixtures, in-vehicle lighting devices, light source devices for video projection devices, and the like.

It is a circuit diagram of the high pressure discharge lamp lighting device of claim 1. It is an operation | movement waveform diagram of the lighting device of FIG. It is a circuit diagram of Example 1 of the present invention. It is a circuit diagram of Example 2 of the present invention. FIG. 5 is an operation waveform diagram of the circuit of FIG. 4. It is a circuit diagram of the conventional high pressure discharge lamp lighting device. It is an operation | movement waveform figure at the time of lighting of a prior art example. It is an operation | movement waveform diagram at the time of the non-lighting of a prior art example. It is an operation waveform diagram at the time of non-lighting when the capacities of the capacitors of the conventional example are different.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control circuit 2 Drive circuit 3 Igniter circuit 4 Pulse generation circuit 5 Auxiliary chopper circuit Q1 1st switching element Q2 2nd switching element Q3 3rd switching element Ce1 1st capacitor Ce2 2nd capacitor C1 3rd capacitor L1 1st inductor DL lamp (High pressure discharge lamp)

Claims (6)

A series circuit of a first capacitor and a second capacitor and a series circuit of a reverse conduction type first switching element and a second switching element are connected in parallel, and a connection point between the first capacitor and the second capacitor and the first capacitor A series circuit of a third capacitor and a first inductor connected in parallel with a lamp as a load is connected between a connection point of the switching element and the second switching element, and the first switching element is connected in the first period. In a high-pressure discharge lamp lighting device that supplies a low-frequency rectangular wave power to a lamp that is a load by turning on and off at a high frequency and turning on and off the second switching element at a high frequency in a second period. And an auxiliary chopper circuit that is connected in parallel to the series circuit of the second capacitor and includes at least one inductor and a switching element. A high pressure discharge lamp in which only one of the first switching element and the second switching element is turned on / off at a high frequency during non-lighting and during a period from when the lamp is started to when the lamp is switched to arc discharge. Lighting device. 2. The high pressure discharge lamp lighting device according to claim 1, wherein a circuit that consumes power of the first capacitor is connected to both ends of the first capacitor. 3. The high pressure discharge lamp lighting device according to claim 2, wherein an igniter circuit is connected as a circuit that consumes the power of the first capacitor. 2. The high pressure discharge lamp lighting device according to claim 1, further comprising a drive circuit that is supplied with power from an inductor of the auxiliary chopper circuit and drives the first and second switching elements. 5. The high pressure discharge lamp lighting device according to claim 4, wherein the inductor is configured as a transformer, and a power source for driving a switching element on a high potential side is supplied by the secondary winding. An illuminating device provided with the high pressure discharge lamp lighting device in any one of Claims 1-5.

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