JP2006066226A - Electrodeless discharge lamp lighting device and illumination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrodeless discharge lamp lighting device which can prevent flickerings of an electrodeless discharge lamp, even if operation of a chopper circuit is stopped once, and to provide an illumination device. <P>SOLUTION: The chopper control circuit 6 comprises a PFC control IC 21 which has the function of stopping the operation of a chopper circuit 3, when the output voltage of the chopper circuit rises in voltage and the detected voltage detected by a voltage detecting circuit 22 surpasses a first threshold voltage and the function of restarting the operation of the chopper circuit 3, when the detected voltage becomes below a second threshold voltage established lower than the first threshold voltage, in a state with the operation of the chopper circuit 3 stopped. The speed of the transient response of the chopper control circuit 6 is determined by an integration circuit 23, and the integration circuit 23 makes the transient response of the chopper control circuit, at least at the restarting of the chopper circuit 3, faster than that at the normal lighting of the electrodeless discharge lamp 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrodeless discharge lamp lighting device and an illuminating device for lighting an electrodeless discharge lamp by applying a high frequency output to an induction coil of an electrodeless discharge lamp in which an induction coil enclosing a discharge gas is disposed in proximity. is there.

  As this type of electrodeless discharge lamp lighting device 1 (hereinafter abbreviated as “lighting device”), generally, as shown in FIG. 10, an electrodeless discharge lamp 2 is lit using an AC power supply AC as a power source. Yes. The lighting device 1 includes a rectifier DB formed of, for example, a diode bridge that rectifies a power supply voltage of an AC power supply AC, a chopper circuit 3 that converts an output of the rectifier DB into a DC voltage having a desired magnitude, and an output of the chopper circuit 3. And a power conversion circuit 4 for turning on the electrodeless discharge lamp 2 by converting it into a high frequency output and applying it to the induction coil 12 of the electrodeless discharge lamp 2. Although not described in detail, the lighting device 1 shown in FIG. 10 has a switching element Q5 between the rectifier DB and the chopper circuit 3, and lowers the output voltage of the chopper circuit 3 during steady lighting of the electrodeless discharge lamp 2. A step-down circuit 15 is provided.

  In the chopper circuit 3, a series circuit of an inductor L1 and a switching element Q1 composed of a MOSFET is connected between the output terminals of the rectifier DB with the inductor L1 as a positive side of the rectifier DB, and a smoothing capacitor is connected between both ends of the switching element Q1. A series circuit of C1 and a diode D1 has a configuration in which the anode of the diode D1 is connected to a connection point between the switching element Q1 and the inductor L1, and outputs an output voltage between both ends of the smoothing capacitor C1. Further, a drive circuit 5 having a drive transformer T1 connected to the switching element Q1 and a chopper control circuit 6 for controlling on / off of the switching element Q1 via the drive transformer T1 are provided. The chopper control circuit 6 is provided with the chopper circuit 3 By performing feedback control of the drive circuit 5 based on the output voltage, the chopper circuit 3 boosts the input voltage from the rectifier DB to a desired magnitude and outputs the boosted voltage.

  On the other hand, the power conversion circuit 4 includes a series circuit of a switching element Q2 and a switching element Q3 made of MOSFET to which the output voltage of the chopper circuit 3 is applied, and a drive circuit 7 that alternately turns on and off the switching elements Q2 and Q3 at a high frequency. Prepare. The drive circuit 7 includes an oscillation circuit 8 having a crystal resonator X1 and an amplification circuit 9 having a drive transformer T2 to which switching elements Q2 and Q3 are respectively connected on the secondary side and amplifying the output of the oscillation circuit 8. Consists of. A drive power supply circuit 10 which is an operation power supply of the drive circuit 7 includes a series circuit of a switching element Q4 and a diode D2 made of a MOSFET connected between output terminals of the chopper circuit 3, an inductor L2 connected in parallel with the diode D2, and A series circuit of the capacitor C3 and a step-down control circuit 11 that detects the voltage across the capacitor C3 so as to step down the output voltage of the chopper circuit 3 and use it as the output of the drive power supply circuit 10 to control on / off of the switching element Q4. Composed. The power conversion circuit 4 gives a high frequency output to the induction coil 12 constituting the electrodeless discharge lamp 2 by alternately turning on and off the switching elements Q2 and Q3 at a high frequency.

  Further, in FIG. 10, a matching circuit 13 for matching impedances of the power conversion circuit 4 and the induction coil 12 is provided so that a high frequency output can be efficiently given from the power conversion circuit 4 to the electrodeless discharge lamp 2. ing. Between the power conversion circuit 4 and the matching circuit 13, a series circuit of an inductor L3 and a capacitor C4 is inserted.

  The induction coil 12 is disposed in the vicinity of the bulb 14 in which a discharge gas (for example, mercury and rare gas), which is a mixed gas of metal vapor and inert gas, is enclosed, and the electrode 14 together with the bulb 14. The electrodeless discharge lamp 2 is turned on by applying a high-frequency electromagnetic field to the discharge gas in the bulb 14 when a high-frequency current of several tens of kHz to several hundreds of MHz flows upon receiving the output of the power conversion circuit 4 (For example, refer to Patent Document 1).

By the way, the electrodeless discharge lamp 2 does not have a filament, and in the lighting device 1 described above, there is no power consumption due to pre-heating when the electrodeless discharge lamp 2 is started (before the operation of the power conversion circuit 4 starts). Therefore, in order to prevent the output voltage of the chopper circuit 3 from excessively rising due to the chopper circuit 3 operating in the same manner as during steady lighting when the electrodeless discharge lamp 2 is started, the output voltage of the chopper circuit 3 is prevented. It is conceivable to add a function to the lighting device 1 to temporarily stop the operation of the chopper circuit 3 when the voltage exceeds a predetermined voltage.
Japanese Patent Laid-Open No. 2002-43082 (page 7-8, FIG. 6)

  However, in the state where the operation of the chopper circuit 3 is stopped in the lighting device 1 described above, the output voltage of the chopper circuit 3 (the voltage across the smoothing capacitor) suddenly increases when power is consumed by lighting the electrodeless discharge lamp 2. Therefore, even if the operation of the chopper circuit 3 is resumed when the output voltage of the chopper circuit 3 falls below a predetermined voltage, the output voltage of the chopper circuit 3 falls below the predetermined voltage. There is a possibility that the electrodeless discharge lamp 2 may flicker due to an undershoot in the output voltage of the chopper circuit 3 during a period from when the chopper circuit 3 resumes operation.

  The present invention has been made in view of the above circumstances, and provides an electrodeless discharge lamp lighting device and an illumination device that can prevent the electrodeless discharge lamp from flickering even if the operation of the chopper circuit is temporarily stopped. Objective.

  The invention of claim 1 includes a chopper circuit that has a switching element and determines the magnitude of a DC voltage supplied and output from a DC power source according to the duty ratio of the switching element, a drive circuit that turns on and off the switching element of the chopper circuit, A power conversion circuit that converts the output of the chopper circuit into a high-frequency output and supplies a high-frequency output to the induction coil of the electrodeless discharge lamp for lighting an electrodeless discharge lamp in which an induction coil is disposed close to a bulb filled with a discharge gas; A voltage detection circuit that detects a voltage proportional to the output voltage of the chopper circuit as a detection voltage, and a chopper control circuit that feedback-controls the drive circuit based on the detection voltage. The chopper control circuit has a predetermined detection voltage. Abnormal voltage booster that stops chopper circuit operation when threshold voltage of 1 is exceeded And a release means for resuming the operation of the chopper circuit when the detected voltage falls below a second threshold voltage set lower than the first threshold voltage in a state where the operation of the chopper circuit is stopped by the abnormal boost prevention means And a transient response control means for making the transient response in the chopper control circuit when the operation of the chopper circuit is restarted at least by the releasing means faster than in the steady lighting of the electrodeless discharge lamp.

  According to this configuration, the transient response of the chopper control circuit when the operation of the chopper circuit is resumed by at least the release means is made faster than that during steady lighting of the electrodeless discharge lamp. The operation of the chopper circuit can be resumed immediately after the detection voltage falls below the second threshold voltage in a state where the operation is stopped. In short, even if the time from when the detected voltage falls below the second threshold voltage to when the chopper circuit operation resumes is short and the chopper circuit operation stops, the output voltage of the chopper circuit suddenly drops. Since the decrease in the output voltage of the chopper circuit is suppressed before it greatly decreases, it is possible to prevent the electrodeless discharge lamp from flickering due to an undershoot in the output voltage of the chopper circuit.

  According to a second aspect of the present invention, in the first aspect of the present invention, when the chopper control circuit stops the operation of the chopper circuit by the abnormal boost prevention means before the power conversion circuit starts operation, the power conversion circuit A timer circuit for timing a fixed time including a period from the start of operation until the operation of the chopper circuit is restarted by the canceling means, and the transient response control means is a period for which the timer circuit times the fixed time Further, the transient response of the chopper control circuit is made faster than that during steady lighting of the electrodeless discharge lamp.

  According to this configuration, even when the output voltage of the chopper circuit suddenly decreases due to the operation of the power conversion circuit with the operation of the chopper circuit stopped when the electrodeless discharge lamp is started, the chopper control circuit Therefore, the electrodeless discharge lamp can be prevented from flickering when the operation of the chopper circuit is resumed by the release means.

  According to a third aspect of the invention, in the first aspect of the invention, the transient response control means is set to be lower than the first threshold voltage and higher than a detection voltage when the electrodeless discharge lamp is steadily lit. When the detected voltage exceeds a third threshold voltage, the transient response of the chopper control circuit is made faster than that during steady lighting of the electrodeless discharge lamp.

  According to this configuration, the electrodeless discharge lamp can be prevented from flickering when the operation of the chopper circuit is resumed by the release means, not only when the electrodeless discharge lamp is started but also during steady lighting.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the third threshold voltage is the first threshold voltage.

  By the way, the transient response of the chopper control circuit prevents the noise and other signals from error sources from being regulated during steady lighting of the electrodeless discharge lamp, leading to deterioration of input current distortion and power factor reduction. Therefore, it is desirable that the setting is relatively slow. According to the fourth aspect of the present invention, since the transient response of the chopper control circuit is accelerated only when the operation of the chopper circuit is stopped by the abnormal boost prevention means, the detection voltage is maintained during steady lighting of the electrodeless discharge lamp. Even if the voltage rises within a range that does not exceed the first threshold voltage, the chopper control circuit can be operated with a slow transient response, and it is not in a state where deterioration of input current distortion and power factor reduction of the chopper circuit are prevented. The electrode discharge lamp can be kept on.

  According to a fifth aspect of the present invention, in the first aspect of the invention, the chopper control circuit includes a change rate detection circuit that detects a change rate of the detection voltage, and the transient response control means is detected by the change rate detection circuit. The transient response of the chopper control circuit is made to be faster than that during steady lighting of the electrodeless discharge lamp during a period in which the change rate exceeds a predetermined value.

  According to this configuration, the electrodeless discharge lamp can be prevented from flickering when the operation of the chopper circuit is resumed by the release means, not only when the electrodeless discharge lamp is started but also during steady lighting.

  According to a sixth aspect of the present invention, the electrodeless discharge lamp lighting device according to any one of the first to fourth aspects and an induction coil that receives a high-frequency output from the power conversion circuit are disposed close to a bulb in which discharge gas is sealed. An electrodeless discharge lamp is provided.

  According to this configuration, the transient response of the chopper control circuit when the operation of the chopper circuit is resumed by at least the release means is made faster than that during steady lighting of the electrodeless discharge lamp. The operation of the chopper circuit can be resumed immediately after the detection voltage falls below the second threshold voltage in a state where the operation is stopped. In short, even if the time from when the detected voltage falls below the second threshold voltage to when the chopper circuit operation resumes is short and the chopper circuit operation stops, the output voltage of the chopper circuit suddenly drops. Since the decrease in the output voltage of the chopper circuit is suppressed before it greatly decreases, it is possible to prevent the electrodeless discharge lamp from flickering due to an undershoot in the output voltage of the chopper circuit.

  In the present invention, since the transient response of the chopper control circuit when the operation of the chopper circuit is resumed by at least the release means is made faster than that during steady lighting of the electrodeless discharge lamp, the operation of the chopper circuit is prevented by the abnormal boost prevention means. There is an effect that the operation of the chopper circuit can be restarted immediately after the detection voltage falls below the second threshold voltage in the stopped state. In short, even if the time from when the detected voltage falls below the second threshold voltage to when the chopper circuit operation resumes is short and the chopper circuit operation stops, the output voltage of the chopper circuit suddenly drops. Since the decrease in the output voltage of the chopper circuit is suppressed before it greatly decreases, it is possible to prevent the electrodeless discharge lamp from flickering due to an undershoot in the output voltage of the chopper circuit.

  In the following embodiments, the same functions and configurations as those of the conventional configuration are denoted by the same reference numerals as those of the conventional configuration, and description thereof is omitted.

(Embodiment 1)
As shown in FIG. 1, the electrodeless discharge lamp lighting device 1 of the present embodiment (hereinafter abbreviated as “lighting device”) includes an inductor L3 and a capacitor C4 between both ends of the switching element Q3 in the power conversion circuit 4. The induction coil 12 which comprises the electrodeless discharge lamp 2 is connected between the both ends of the capacitor | condenser C4 via the capacitors C5 and C6. The inductor L3 and the capacitors C4 to C6 constitute the load circuit L together with the electrodeless discharge lamp 2. Although omitted in FIG. 1, a line filter is inserted between the AC power supply AC and the rectifier DB to prevent high frequency components from leaking to the AC power supply AC side when the chopper circuit 3 operates.

  An electrodeless discharge lamp 2 shown in FIG. 1 is formed in a shape in which a bulb 14 has a recess 16 that is recessed upward in the figure, and a cylindrical core 17 around which an induction coil 12 is wound. Has been inserted. The core 17 is formed using a magnetic material, and a heat conductive member 18 formed using a heat conductive material is provided inside the core 17 in contact with the core 17. The heat conducting member 18 is extended to the outside of the valve 14, and the tip protruding from the valve 14 is fixed to a disk-shaped base 19. A cover 20 is provided between the base 19 and the valve 14 to surround the periphery of the heat conducting member 18. Here, as shown in FIG. 2, the lighting device 1 of the present embodiment is accommodated in the space surrounded by the cover 20 between the base 19 and the bulb 14 in the electrodeless discharge lamp 2 described above. An illumination device that turns on the electrode discharge lamp 2 is configured. In this lighting device, the induction coil 12 is housed in the concave portion 16 of the bulb 14, and the lighting device 1 is housed between the bulb 14 and the base 19, so that the overall shape is relatively compact. . The lighting device shown in FIG. 2 is formed in a shape that can be attached to a socket (not shown) for an incandescent lamp.

  In the present embodiment, the PFC control IC 21 is used as a component of the chopper control circuit 6, and the function as the oscillation circuit 8 (see FIG. 10) in the drive circuit 7 of the power conversion circuit 4 is provided in the PFC control IC 21. Furthermore, a voltage detection circuit 22 that detects a voltage proportional to the output voltage of the chopper circuit 3 as a detection voltage is provided. The PFC control IC 21 incorporates an error amplifier (not shown) in which the detection voltage is input to the inverting input terminal, and feedback-controls the drive circuit 5 based on the detection voltage. In the lighting device 1 of FIG. 1, the PFC control IC 21 determines the duty ratio of the switching element Q1 of the chopper circuit 3 so that the output voltage of the chopper circuit 3 is kept constant. The voltage detection circuit 22 is a series circuit of a voltage dividing resistor R1 and a voltage dividing resistor R2 connected between output ends of the chopper circuit 3 (that is, between both ends of the smoothing capacitor C1), and is a low potential side of the chopper circuit 3. Is output to the PFC control IC 21 as a detection voltage, which is generated between the output terminal of the first and second voltage dividing resistors R1 and R2.

  By the way, the PFC control IC 21 stops the operation of the chopper circuit 3 by stopping the output to the drive circuit 5 when the detected voltage exceeds the first threshold voltage Vth1 (see FIG. 3). It has the function as. Further, when the detected voltage falls below the second threshold voltage Vth2 which is set lower than the first threshold voltage Vth1 in a state where the operation of the chopper circuit 3 is stopped by the abnormal boost prevention means, the PFC control IC 21 drives A function as release means for resuming the operation of the chopper circuit 3 by resuming the output to the circuit 5 is provided. Here, the first threshold voltage Vth1 is set higher than the detection voltage during steady lighting of the electrodeless discharge lamp 2, and the second threshold voltage Vth2 determines the output voltage of the chopper circuit 3 as an electrodeless discharge lamp. 2 is set to a magnitude between the detection voltage when the minimum voltage necessary for lighting 2 is set and the detection voltage when the electrodeless discharge lamp 2 is steadily lit.

  Here, in the present embodiment, even if the output voltage of the chopper circuit 3 suddenly decreases in a state where the operation of the chopper circuit 3 is stopped by the abnormal boost prevention means, the chopper circuit 3 is not yet operated until the operation of the chopper circuit 3 is resumed. The transient response of the chopper control circuit 6 when the operation of the chopper circuit 3 is resumed at least by the release means is made relatively fast so that the undershoot can be prevented from occurring in the output voltage. However, when the electrodeless discharge lamp 2 is steadily lit, noise or a signal from another error generation source (for example, the ripple voltage of the smoothing capacitor C1 by the AC power supply AC) is regulated to deteriorate the input current distortion or reduce the power factor. It is desirable to make the transient response of the chopper control circuit 6 relatively slow. Therefore, in the present embodiment, the speed of the transient response of the chopper control circuit 6 is switched after the operation of the chopper circuit 3 is restarted by the release means, and the transient response of the chopper control circuit 6 is changed during steady lighting of the electrodeless discharge lamp 2. Make it relatively slow.

  More specifically, in the lighting device 1 of the present embodiment, an integration circuit 23 as a transient response control means for changing the speed of the transient response of the chopper control circuit 6 is connected to the output terminal Out of the error amplifier in the PFC control IC 21. It is connected. The integrating circuit 23 changes the speed of the transient response of the PFC control IC 21 according to the time constant of the circuit. In this embodiment, the integrating circuit 23 has a parallel circuit of a resistor R3 and a capacitor C7 to which the output voltage of the error amplifier is applied. . Here, a series circuit of the capacitor C8 and the switch means SW1 is connected in parallel to the capacitor C7, and when the switch means SW1 is on, the capacitance component of the capacitor C8 is added to the capacitance component of the capacitor C7. The transient response of the PFC control IC 21 becomes slower than the period when the switch means SW1 is off. Although not shown here, the integrating circuit 23 may be connected in parallel to the voltage dividing resistor R2 of the voltage detecting circuit 22, for example.

  The chopper control circuit 6 has a timer circuit 24 connected to the PFC control IC 21 as means for turning on / off the switch means SW1. The timer circuit 24 receives a signal for starting the operation of the power conversion circuit 4 from the PFC control IC 21 so that the switch means SW1 is turned off for a predetermined time after the operation of the power conversion circuit 4 is started. In the following, it will be called “timer time”). Here, when the timer circuit 24 turns on the switch means SW1 at the end of the timed operation, the capacitance component of the capacitor C8 is added to the integrating circuit 23, and the transient response of the PFC control IC 21 is delayed.

  The operation of the above-described lighting device 1 will be described below with reference to FIG. 3 showing the change over time of the detected voltage, taking the case of starting the electrodeless discharge lamp 2 as an example. In FIG. 3, the horizontal axis is the time axis, and the magnitude of the detected voltage is the vertical axis. A period in which the transient response of the chopper control circuit 6 is fast is indicated by “response speed” in the drawing, and a period in which the transient response of the chopper control circuit 6 is slow is indicated by “response delay” in the drawing. Further, since the detection voltage is obtained by dividing the voltage across the smoothing capacitor C1 that is the output voltage of the chopper circuit 3, the magnitude of the detection voltage is proportional to the magnitude of the output voltage of the chopper circuit 3.

  First, when the AC power supply AC is turned on at time t0, the smoothing capacitor C1 is charged and the detection voltage rises to Vc1 before the chopper circuit 3 starts operating.

  Next, at time t1, the chopper circuit 3 starts operating, and the voltage across the smoothing capacitor C1, which is the output voltage of the chopper circuit 3, begins to rise. Here, since the power conversion circuit 4 has not yet started operation, power supply to the electrodeless discharge lamp 2 is not performed, and a light load state occurs, and the voltage across the smoothing capacitor C1 is a chopper during steady lighting of the electrodeless discharge lamp 2. It rises further beyond the output voltage of circuit 3.

  When the detected voltage exceeds the first threshold voltage Vth1 at time t2, the operation of the chopper circuit 3 is stopped by the abnormal boost prevention means of the PFC control IC 21, and then the time t3 when the power conversion circuit 4 starts operating. During this period, the voltage across the smoothing capacitor C1 is kept substantially constant. When the power conversion circuit 4 starts operating at time t3, power starts to be supplied to the electrodeless discharge lamp 2, and thus the voltage across the smoothing capacitor C1 starts to decrease. On the other hand, the timer circuit 24 starts the timed operation from the time t3 when the power conversion circuit 4 starts the operation, and then limits the timer time Ta until the time t6.

  When the detected voltage falls below the second threshold voltage Vth2 at time t4, the release means of the PFC control IC 21 tries to restart the operation of the chopper circuit 3. Here, during the period from time t3 to time t6, since the timer circuit 24 is in a timed operation of the timer time Ta and the transient response of the chopper control circuit 6 is relatively fast, the chopper circuit at time t5 immediately after time t4. 3 resumes operation, and the electrodeless discharge lamp 2 is normally lit. That is, the time from the time t4 to the time t5 is short, and the operation of the chopper circuit 3 is restarted before the voltage across the smoothing capacitor C1 greatly decreases (undershoot occurs), thereby suppressing the decrease in the voltage across the smoothing capacitor C1. Therefore, it is possible to prevent the electrodeless discharge lamp 2 from flickering due to an undershoot in the voltage across the smoothing capacitor C1.

  Then, when the timer circuit 24 ends the timed operation at time t6, the transient response of the chopper control circuit 6 is switched and delayed. Therefore, at the time of steady lighting of the electrodeless discharge lamp 2 after time t6, the electrodeless discharge lamp 2 can be kept lit while preventing the input current distortion of the chopper circuit 3 from deteriorating and the power factor from being lowered.

  In the example shown in FIG. 3, the transient response of the chopper control circuit 6 is accelerated before the time t3 when the timer circuit 24 starts the timed operation, but the chopper control is performed simultaneously with the timer circuit 24 starting the timed operation. The circuit 6 may be configured to speed up the transient response.

  In addition to the lighting device shown in FIG. 2, for example, as shown in FIG. 4, a lighting device in which the bulb 14 can be removed from the upper side of the drawing can be configured. 4 includes an upper body 25 that houses the bulb 14, a lower body 26 that houses the core 17 and the base 19 around which the induction coil 12 is wound, and the lighting device 1 includes the lower body 26. It is fixed to the base 19 inside. This illuminating device can light the electrodeless discharge lamp 2 in a state where the upper body 25 and the lower body 26 are combined so that the induction coil 12 is close to the bulb 14. A shield case 27 that absorbs radiation noise from the electrodeless discharge lamp 2 is provided in a part of the upper body 25 so as to cover the bulb 14. However, the illuminating device comprised using the lighting device 1 and the electrodeless discharge lamp 2 is not limited to what was shown in FIG. 2 or FIG. 4 mentioned above.

  In the following embodiments, the same functions and configurations as those of the first embodiment are denoted by the same reference numerals as those of the conventional configuration, and the description thereof is omitted. 5, 7, and 9 showing the configuration of each embodiment, only the main part of the lighting device 1 is shown. 4 is omitted.

(Embodiment 2)
The lighting device 1 of the present embodiment is that the transient response of the chopper control circuit 6 is made faster than the steady lighting of the electrodeless discharge lamp 2 when the detected voltage exceeds the third threshold voltage. Different from the device 1. The third threshold voltage is selected from a range higher than the detection voltage during steady lighting of the electrodeless discharge lamp 2 and lower than the first threshold voltage. In the present embodiment, the third threshold voltage is the same as the first threshold voltage. Is set to

  More specifically, as shown in FIG. 5, the chopper control circuit 6 of the present embodiment includes a comparator CP1 that compares the detected voltage with the third threshold voltage Vth3, and an output voltage of the comparator CP1. A comparison circuit 28 including a series circuit of an applied diode D3 and a capacitor C9 and a resistor R4 connected in parallel to the diode D3 is provided. The third threshold voltage Vth3 is input from the reference power supply Vref to the comparator CP1, and the comparator CP1 charges the capacitor C9 through the diode D3 during a period when the detected voltage exceeds the third threshold voltage Vth3. To do. With this configuration, the comparison circuit 28 allows a certain time period determined by the time constant of the capacitor C9 and the resistor R4 after the detection voltage exceeds the third threshold voltage Vth3 and then the detection voltage falls below the third threshold value. The ON signal is output from the output terminal of the comparator CP1 during the period until this is done.

  In the lighting device 1 of FIG. 5, the integrating circuit 23 serving as a transient response control unit is replaced by the parallel connection of the capacitor C10 and the switch unit SW2 between both ends of the resistor R3, instead of the series circuit of the capacitor C8 and the switch unit SW1 in the first embodiment. The circuit has a configuration connected in series with a capacitor C7. As a result, since the capacitance component of the capacitor C10 is added to the capacitance component of the capacitor C7 when the switch means SW2 is off, the transient response of the PFC control IC 21 becomes slower than the period when the switch means SW2 is on. Here, the output terminal of the comparator CP1 is connected to the switch means SW2, and when the detection voltage exceeds the third threshold voltage, the switch means SW2 is turned on in response to the on signal, thereby turning on the PFC control IC 21. The transient response is faster than when the electrodeless discharge lamp 2 is steadily lit.

  The operation of the lighting device 1 described above will be described below with reference to FIG. 6 showing the change over time of the detected voltage, taking as an example the start of the electrodeless discharge lamp 2. In FIG. 6, the horizontal axis is the time axis, and the magnitude of the detected voltage is taken on the vertical axis. The period in which the transient response of the chopper control circuit 6 is fast is indicated by “response speed” in the figure, and the transient response of the chopper control circuit 6 is shown. The period when the response time is slow is indicated by “response delay” in the figure. Further, once the detection voltage exceeds the third threshold voltage Vth3, the comparison circuit 28 outputs an ON signal until a predetermined time Tb elapses after the detection voltage falls below the third threshold voltage Vth3. Shall continue.

  When the detection voltage exceeds the first threshold voltage Vth1 at time t2, the operation of the chopper circuit 3 is stopped by the abnormal boost prevention means of the PFC control IC 21, and then the time t3 when the power conversion circuit 4 starts operation. During this period, the voltage across the smoothing capacitor C1 is kept substantially constant. When the power conversion circuit 4 starts operating at time t3, power starts to be supplied to the electrodeless discharge lamp 2, and thus the voltage across the smoothing capacitor C1 starts to decrease. On the other hand, at time t2, the detection voltage exceeds the first threshold voltage Vth1, and at the same time exceeds the third threshold voltage Vth3, so that the comparison circuit 28 detects the detection voltage from time t2 to time t3. The ON signal is output in a period from time t6 when the voltage falls below the third threshold voltage to time t6 when a certain time Tb elapses.

  When the detected voltage falls below the second threshold voltage Vth2 at time t4, the release means of the PFC control IC 21 tries to restart the operation of the chopper circuit 3. Here, during the period from time t2 to time t6, the switching means SW2 of the integration circuit 23 is in the ON state and the transient response of the chopper control circuit 6 is relatively fast, so the chopper circuit 3 at time t5 immediately after time t4. Resumes operation, and the electrodeless discharge lamp 2 is normally lit. That is, the time from the time t4 to the time t5 is short, and the operation of the chopper circuit 3 is restarted before the voltage across the smoothing capacitor C1 greatly decreases (undershoot occurs), thereby suppressing the decrease in the voltage across the smoothing capacitor C1. Therefore, it is possible to prevent the electrodeless discharge lamp 2 from flickering due to an undershoot in the voltage across the smoothing capacitor C1.

  Then, when the output of the ON signal from the comparison circuit 28 stops at time t6, the transient response of the chopper control circuit 6 is switched and delayed. Therefore, at the time of steady lighting of the electrodeless discharge lamp 2 after time t6, the electrodeless discharge lamp 2 can be kept lit while preventing the input current distortion of the chopper circuit 3 from deteriorating and the power factor from being lowered.

  In the lighting device 1 according to the present embodiment, the output voltage of the chopper circuit 3 is not limited to when the electrodeless discharge lamp 2 is started as described above, but during steady lighting, for example, a surge voltage is input to the chopper circuit 3. Even if the voltage rises abnormally, there is an effect of preventing the electrodeless discharge lamp 2 from flickering when the operation of the chopper circuit 3 stopped by the abnormal voltage rise prevention means is restarted.

  The third threshold voltage Vth3 only needs to be selected from a range higher than the detection voltage during steady lighting of the electrodeless discharge lamp 2 and lower than the first threshold voltage Vth1. The value is not limited to the same value as the value voltage Vth1. However, if the third threshold voltage Vth3 is set to the same value as the first threshold voltage Vth1, the transient response of the chopper control circuit 6 only when the operation of the chopper circuit 3 is stopped by the abnormal boost prevention means. Therefore, even if the detection voltage rises within a range not exceeding the first threshold voltage Vth1 when the electrodeless discharge lamp 2 is steadily lit, the transient response of the chopper control circuit 6 can be operated while being slow. The electrodeless discharge lamp 2 can be kept on in a state where deterioration of input current distortion and power factor reduction of the chopper circuit 3 are prevented. Other configurations and functions are the same as those of the first embodiment.

(Embodiment 3)
As shown in FIG. 7, the lighting device 1 of the present embodiment includes a change rate detection circuit 29 in which the chopper control circuit 6 detects a change rate of the detected voltage, and the change rate detected by the change rate detection circuit 29 is It differs from the lighting device 1 of the second embodiment in that the transient response of the chopper control circuit 6 is made faster than that during steady lighting of the electrodeless discharge lamp 2 during a period exceeding the predetermined value.

  The change rate detection circuit 29 of the present embodiment outputs an ON signal during a period when the change rate of the detection voltage exceeds a predetermined value, and when the detection voltage changes faster than the transient response of the chopper control circuit 6. An ON signal is output, and conversely, when the detected voltage changes later than the transient response of the chopper control circuit 6, the ON signal is stopped. That is, the change rate of the detection voltage means the speed at which the detection voltage changes. Here, the output terminal of the change rate detection circuit 29 is connected to the switch means SW2 of the integration circuit 23, and the switch means SW2 receives an ON signal and is turned on during a period when the change rate of the detection voltage exceeds a predetermined value. The transient response of the PFC control IC 21 becomes faster than when the electrodeless discharge lamp 2 is steadily lit.

  The operation of the above-described lighting device 1 will be described below with reference to FIG. 8 showing the change over time of the detected voltage, taking the electrodeless discharge lamp 2 as an example. In FIG. 8, the horizontal axis is the time axis and the magnitude of the detected voltage is the vertical axis. The period in which the transient response of the chopper control circuit 6 is fast is indicated by “response speed” in the figure, and the transient response of the chopper control circuit 6 is shown. The period when the response time is slow is indicated by “response delay” in the figure.

  When the detection voltage exceeds the first threshold voltage Vth1 at time t2, the operation of the chopper circuit 3 is stopped by the abnormal boost prevention means of the PFC control IC 21, and then the time t3 when the power conversion circuit 4 starts operation. During this period, the voltage across the smoothing capacitor C1 is kept substantially constant. When the power conversion circuit 4 starts operating at time t3, power begins to be supplied to the electrodeless discharge lamp 2, and thus the voltage across the smoothing capacitor C1 begins to decrease. Here, during the period in which the voltage across the smoothing capacitor C1 drops, the change rate of the detection voltage exceeds a predetermined value, and the change rate detection circuit 29 outputs an ON signal.

  When the detected voltage falls below the second threshold voltage Vth2 at time t4, the release means of the PFC control IC 21 tries to restart the operation of the chopper circuit 3. Here, during the period in which the voltage across the smoothing capacitor decreases (period from time t3 to time t5), the switching means SW2 of the integrating circuit 23 is in the ON state, and the transient response of the chopper control circuit 6 is relatively fast. At time t5 immediately after time t4, the chopper circuit 3 resumes operation, and the electrodeless discharge lamp 2 is normally lit. That is, the time from the time t4 to the time t5 is short, and the operation of the chopper circuit 3 is restarted before the voltage across the smoothing capacitor C1 greatly decreases (undershoot occurs), thereby suppressing the decrease in the voltage across the smoothing capacitor C1. Therefore, it is possible to prevent the electrodeless discharge lamp 2 from flickering due to an undershoot in the voltage across the smoothing capacitor C1.

  Thereafter, when the voltage across the smoothing capacitor C1 becomes substantially constant at time t7, the ON signal from the change rate detection circuit 29 stops, and the transient response of the chopper control circuit 6 is switched and delayed. Therefore, at the time of steady lighting of the electrodeless discharge lamp 2 after time t7, the electrodeless discharge lamp 2 can be kept lit in a state where deterioration of input current distortion and power factor reduction of the chopper circuit 3 are prevented.

  In the lighting device 1 according to the present embodiment, the output voltage of the chopper circuit 3 is not limited to when the electrodeless discharge lamp 2 is started as described above, but during steady lighting, for example, a surge voltage is input to the chopper circuit 3. Even if the voltage rises abnormally, there is an effect of preventing the electrodeless discharge lamp 2 from flickering when the operation of the chopper circuit 3 stopped by the abnormal voltage rise prevention means is restarted.

  Also, the PFC control IC 21 shown in FIG. 7 functions as an abnormal operation preventing means for stopping the operation of the chopper circuit 3 when the detected voltage falls below a predetermined fourth threshold voltage during steady lighting of the electrodeless discharge lamp 2. Is further provided. The fourth threshold voltage is set lower than the detection voltage when the output voltage of the chopper circuit 3 is set to the minimum voltage necessary for lighting the electrodeless discharge lamp 2. Other configurations and functions are the same as those of the second embodiment.

(Embodiment 4)
In the lighting device 1 of the present embodiment, as shown in FIG. 9, the input monitoring circuit 30 in which the chopper control circuit 6 switches the speed of the transient response of the chopper control circuit 6 by the output of the AC power supply AC (input of the chopper circuit 3). Is different from the lighting device 1 of the second embodiment.

  The integrating circuit 23 shown in FIG. 9 has a configuration in which a series circuit of a capacitor C11, a resistor R5, and a switch means SW3 is connected between both ends of the resistor R3 in the integrating circuit 23 of the second embodiment. As a result, since the capacitance component of the capacitor C11 is added to the integrating circuit 23 while the switch means SW3 is on, the transient response of the PFC control IC 21 is delayed as compared with the period when the switch means SW3 is off. 9 detects the input voltage of the chopper circuit 3 after the AC power supply AC is turned on, and switches the switch means SW3 on and off by the power supply voltage (for example, 100 V and 200 V) of the AC power supply AC.

  Here, the optimum speed of the transient response in the chopper control circuit 6 for preventing the input current distortion of the chopper circuit 3 from deteriorating and the power factor from being lowered varies depending on the voltage input to the chopper circuit 3. According to the configuration of FIG. 9, the lighting device 1 switches the speed of the transient response of the chopper control circuit 6 to a speed suitable for the power supply voltage of the AC power supply AC. It is possible to further prevent the deterioration of the input current distortion and the power factor reduction.

  The input monitoring circuit 30 is configured to detect the frequency of the AC power supply AC instead of the input voltage of the chopper circuit 3 and switch the speed of the transient response of the chopper control circuit 6 based on this frequency (for example, 50 Hz and 60 Hz). May be. In this case, the speed of the transient response of the chopper control circuit 6 can be set to a speed suitable for each frequency of the AC power supply AC, and the input current distortion of the chopper circuit 3 can be reduced when the electrodeless discharge lamp 2 is steadily lit. Deterioration and power factor reduction can be further prevented. Other configurations and functions are the same as those of the second embodiment.

It is a circuit diagram which shows the structure of Embodiment 1 of this invention. It is sectional drawing which shows an illuminating device same as the above. It is operation | movement explanatory drawing which shows the operation | movement at the time of a start of an electrodeless discharge lamp same as the above. It is sectional drawing which shows the other illuminating device same as the above. It is a circuit diagram which shows the structure of Embodiment 2 of this invention. It is operation | movement explanatory drawing which shows the operation | movement at the time of a start of an electrodeless discharge lamp same as the above. It is a circuit diagram which shows the structure of Embodiment 3 of this invention. It is operation | movement explanatory drawing which shows the operation | movement at the time of a start of an electrodeless discharge lamp same as the above. It is a circuit diagram which shows the structure of Embodiment 4 of this invention. It is a circuit diagram which shows the structure of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrodeless discharge lamp lighting device 2 Electrodeless discharge lamp 3 Chopper circuit 4 Power conversion circuit 5 Drive circuit 6 Chopper control circuit 12 Induction coil 14 Valve 22 Voltage detection circuit 23 Integration circuit (transient response control means)
24 timer circuit 29 change rate detection circuit Q1 switching element Vth1 first threshold voltage Vth2 second threshold voltage Vth3 third threshold voltage

Claims (6)

  A chopper circuit that has a switching element and determines the magnitude of the DC voltage supplied and output from the DC power supply based on the duty ratio of the switching element, a drive circuit that turns on and off the switching element of the chopper circuit, and a high-frequency output of the output of the chopper circuit A power conversion circuit that supplies a high-frequency output to the induction coil of the electrodeless discharge lamp, and a chopper circuit output voltage. A voltage detection circuit that detects a proportional voltage as a detection voltage, and a chopper control circuit that feedback-controls the drive circuit based on the detection voltage. The chopper control circuit has a predetermined first threshold voltage as a detection voltage. Abnormal boost prevention means to stop chopper circuit operation when exceeded, and abnormal boost prevention A release means for restarting the operation of the chopper circuit when the detected voltage falls below a second threshold voltage set lower than the first threshold voltage in a state where the operation of the chopper circuit is stopped by the stage, and at least the release means And a transient response control means for making the transient response in the chopper control circuit when the operation of the chopper circuit resumes faster than during steady lighting of the electrodeless discharge lamp.   When the operation of the chopper circuit is stopped by the abnormal boost prevention means before the power conversion circuit starts operation, the chopper control circuit starts the operation of the chopper circuit after the power conversion circuit starts operating. And a transient response control means, wherein the transient response control means transmits the transient response of the chopper control circuit to the electrodeless discharge lamp during a period when the timer circuit times the fixed time. 2. The electrodeless discharge lamp lighting device according to claim 1, wherein the lighting speed is higher than that during steady lighting.   When the detected voltage exceeds the third threshold voltage that is lower than the first threshold voltage and higher than the detected voltage during steady lighting of the electrodeless discharge lamp, the transient response control means 2. The electrodeless discharge lamp lighting device according to claim 1, wherein a transient response of the chopper control circuit is made faster than that during steady lighting of the electrodeless discharge lamp.   The electrodeless discharge lamp lighting device according to claim 3, wherein the third threshold voltage is the first threshold voltage.   The chopper control circuit includes a change rate detection circuit that detects a change rate of the detection voltage, and the transient response control means is configured to detect a change rate of the chopper control circuit during a period in which the change rate detected by the change rate detection circuit exceeds a predetermined value. 2. The electrodeless discharge lamp lighting device according to claim 1, wherein a transient response is made faster than during steady lighting of the electrodeless discharge lamp.   An electrodeless discharge lamp lighting device according to any one of claims 1 to 4, and an electrodeless discharge lamp in which an induction coil that receives a high-frequency output from the power conversion circuit is disposed close to a bulb in which discharge gas is sealed. A lighting device comprising:

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