JP2013239389A - Discharge lamp lighting device and illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device in which the circuit configuration for determining necessity of protective operation is simple, and the circuit loss is small.SOLUTION: In a discharge lamp lighting device 101, a detection circuit 131 outputting a detection voltage corresponding to the lamp voltage of a discharge lamp FL outputs the detection voltage while dividing it at different ratios for the positive side voltage and the negative side voltage. A control circuit 140 compares the positive side voltage and the negative side voltage of the detection voltage output from the detection circuit 131 with predetermined positive side protection voltage Vth1 and negative side protection voltage Vth2, and controls oscillation operation of an inverter circuit 130 depending on the comparison result.

Description

  The present invention relates to a discharge lamp lighting device and a lighting device.

  In a discharge lamp lighting device for dimming and lighting a discharge lamp by controlling an inverter circuit based on a dimming signal transmitted from a dimmer, a detection circuit detects a voltage corresponding to the voltage of the discharge lamp being lit. Output to the control circuit, and when the voltage output from the detection circuit is higher than a preset protection voltage, the control circuit stops oscillation of the inverter circuit (for example, see Patent Document 1). In this discharge lamp lighting device, in order to prevent erroneous determination of “the state in which the lamp is dimmed” as “the state at the end of life”, the control circuit controls the dimming command value voltage ( Change command signal), and the detection circuit changes the output characteristics of the detected voltage in accordance with the dimming command value voltage.

JP 2011-90790 A

  In a conventional discharge lamp lighting device, a circuit for receiving a dimming signal from a dimmer and generating a dimming command value voltage is required for the control circuit, and the dimming command value voltage is input to the detection circuit. There is a problem that the circuit configuration is complicated and the circuit loss increases, such as the need for a circuit.

  An object of the present invention is, for example, to provide a discharge lamp lighting device that has a simple circuit configuration for appropriately determining whether or not a protection operation is necessary and that has a small circuit loss.

A discharge lamp lighting device according to one aspect of the present invention,
A discharge lamp lighting device that generates high-frequency power by an oscillation operation of an inverter circuit, and supplies the generated high-frequency power to a discharge lamp to light the discharge lamp.
A detection circuit for detecting a voltage corresponding to a lamp voltage of the discharge lamp and outputting the detected voltage as a detection voltage, wherein the detection voltage is divided and output at a different ratio between a positive voltage and a negative voltage. Circuit,
The positive voltage and the negative voltage of the detection voltage output from the detection circuit are compared with a predetermined positive protection voltage and a negative protection voltage, and the inverter circuit oscillates according to the comparison result. And a control circuit for controlling the operation.

  In the discharge lamp lighting device according to one aspect of the present invention, the detection circuit that outputs the detection voltage corresponding to the lamp voltage of the discharge lamp has the detection voltage at different ratios between the positive voltage and the negative voltage. Divide and output. Then, the control circuit compares the positive side voltage and the negative side voltage of the detection voltage output from the detection circuit with a predetermined positive side protection voltage and a negative side protection voltage, and according to the comparison result. Controls the oscillation operation of the inverter circuit. Therefore, according to one aspect of the present invention, the circuit configuration for appropriately determining whether or not the protection operation is necessary is simplified, and the circuit loss is also reduced.

FIG. 2 is a block diagram illustrating a configuration of the illumination system according to Embodiment 1. FIG. 2 is a circuit diagram showing a configuration of a discharge lamp lighting device according to Embodiment 1. FIG. 6 is a circuit diagram showing a configuration of a detection circuit according to Comparative Example 1; FIG. 6 is a circuit diagram showing a configuration of a detection circuit according to Comparative Example 2. FIG. 3 is a circuit diagram illustrating a configuration example of a detection circuit according to the first embodiment. The figure which shows the voltage waveform of D terminal of the detection circuits which concern on the comparative examples 1 and 2 and Embodiment 1. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of illumination system 100 according to the present embodiment.

  1, a lighting system 100 includes a dimmer 200 that transmits a dimming signal, and a plurality of lighting devices 101a, 101b,..., 101n that receive the dimming signal from the dimmer 200 via a signal line. And. Each lighting device includes a discharge lamp FL (lamp) and a discharge lamp lighting device 101 described below.

  FIG. 2 is a circuit diagram showing a configuration of the discharge lamp lighting device 101.

  In FIG. 2, the discharge lamp lighting device 101 receives a dimming signal that commands the dimming rate of the discharge lamp FL from the dimmer 200, and controls the inverter circuit 130 based on the received dimming signal. The discharge lamp FL is dimmed. Specifically, the discharge lamp lighting device 101 generates high frequency power by the oscillation operation of the inverter circuit 130 and supplies the generated high frequency power to the discharge lamp FL. At this time, the oscillation frequency of the inverter circuit 130 is controlled in accordance with the dimming rate commanded by the dimming signal. The discharge lamp FL is lit by the high frequency power supplied from the discharge lamp lighting device 101.

  The discharge lamp lighting device 101 includes a detection circuit 131 (voltage generation unit) and a control circuit 140 (inverter control unit). The detection circuit 131 detects a voltage corresponding to the lamp voltage of the discharge lamp FL and outputs it as a detection voltage. At this time, the detection circuit 131 divides and outputs the detection voltage at a different ratio between the positive voltage and the negative voltage. The control circuit 140 compares the positive side voltage and the negative side voltage of the detection voltage output from the detection circuit 131 with a predetermined positive side protection voltage Vth1 and a negative side protection voltage Vth2, and obtains a comparison result. Accordingly, the oscillation operation of the inverter circuit 130 is controlled.

  Specifically, in the detection circuit 131, the positive voltage of the detection voltage corresponding to the lamp voltage of the discharge lamp FL in the end-of-life state and the all-lights-on state is higher than the positive-side protection voltage Vth1. It corresponds to the lamp voltage of the discharge lamp FL in a normal state (a state where there is no malfunction such as a slow leak and is not at the end of its life) and the light is dimmed at a predetermined dimming rate The positive voltage is set (divided) so that the positive voltage of the detected voltage is equal to or lower than the positive protective voltage Vth1.

  In addition, the detection circuit 131 has a negative voltage on the negative side of the detection voltage corresponding to the lamp voltage of the discharge lamp FL in a state where the slow leak has occurred and the light is dimmed at a predetermined dimming rate. The negative side voltage of the detection voltage corresponding to the lamp voltage of the discharge lamp FL in a state where the voltage is higher than the voltage Vth2 and in a normal state where all the lights are lit is equal to or lower than the negative side protection voltage Vth2. Set (divide) the negative voltage.

  The control circuit 140 stops the oscillation operation of the inverter circuit 130 when the positive voltage of the detection voltage output from the detection circuit 131 is higher than the positive protection voltage Vth1. The control circuit 140 also stops the oscillation operation of the inverter circuit 130 when the negative voltage of the detection voltage output from the detection circuit 131 is higher than the negative protection voltage Vth2. That is, the control circuit 140 determines that the positive voltage of the detection voltage output from the detection circuit 131 is higher than the positive protection voltage Vth1, and the negative voltage of the detection voltage output from the detection circuit 131 is negative. When the voltage is higher than the protection voltage Vth2 on the side, the protection operation is performed.

  In addition, the control circuit 140 is configured such that the positive voltage of the detection voltage output from the detection circuit 131 is equal to or lower than the positive protection voltage Vth1, and the negative voltage of the detection voltage output from the detection circuit 131 is negative. When the voltage is equal to or lower than the protection voltage Vth2 on the side, the oscillation frequency of the inverter circuit 130 is controlled according to the dimming signal input from the dimmer 200.

  The discharge lamp lighting device 101 includes a noise filter 110, a rectifier DB, and a boost chopper circuit 120 in addition to the inverter circuit 130 and the control circuit 140 described above. The noise filter 110 includes a capacitor CN and a common mode choke L3, and is connected between the AC power supply Vac and the rectifier DB for noise removal. The rectifier DB is composed of a diode bridge that performs full-wave rectification of AC power supplied from the AC power supply Vac via the noise filter 110. The step-up chopper circuit 120 is connected between the DC output terminals of the rectifier DB, and converts the output of the rectifier DB into a predetermined DC output. The inverter circuit 130 turns on the discharge lamp FL at a high frequency by converting the DC output of the step-up chopper circuit 120 into high frequency power and supplying it to the discharge lamp FL. The inverter circuit 130 includes the detection circuit 131 described above. The control circuit 140 is a microcomputer, for example, and controls the boost chopper circuit 120 and the inverter circuit 130 including the detection circuit 131.

  Hereinafter, the boost chopper circuit 120 will be described.

  The step-up chopper circuit 120 has an inductor L2 having one end connected to the high potential side of the rectifier DB, a switching element Q3 (for example, a MOSFET) connected to the other end of the inductor L2, and a switching element Q3 and an inductor L2 having an anode terminal. Is connected in parallel to the smoothing capacitor C1, a diode D1 connected to the connection point, a smoothing capacitor C1 whose positive electrode is connected to the cathode terminal of the diode D1, and whose negative electrode is connected to the low potential side of the rectifier DB. The voltage detection circuit 121 is provided.

  The switching element Q3 is turned on / off by the control circuit 140 at a frequency (for example, several hundred kHz) sufficiently higher than the power supply frequency of the AC power supply Vac.

  In step-up chopper circuit 120, when switching element Q3 is turned on / off, the energy accumulated in inductor L2 during the on period of switching element Q3 is released through diode D1 during the off period of switching element Q3. Since the smoothing capacitor C1 is charged in such a manner that the energy discharged from the inductor L2 is superimposed on the output of the rectifier DB, the voltage across the smoothing capacitor C1 can be boosted higher than the output voltage of the rectifier DB.

  The voltage detection circuit 121 includes resistors R1 and R2 connected in series. In this voltage detection circuit 121, the voltage across the smoothing capacitor C1 is divided by resistors R1 and R2, and the voltage across the resistor R2 is input to the control circuit 140. The control circuit 140 to which the voltage across the resistor R2 is input turns on and off the switching element Q3 based on the output of the voltage detection circuit 121 (the voltage across the resistor R2) so that the voltage across the smoothing capacitor C1 is constant. .

  Hereinafter, the inverter circuit 130 will be described.

  In the half-bridge type inverter circuit 130, a series circuit of switching elements Q 1 and Q 2 (for example, MOSFET) and a detection circuit 131 is connected between both ends of a smoothing capacitor C 1 that is an output end of the boost chopper circuit 120. A series circuit of a ballast choke L1, which is a current limiting element, a discharge lamp FL, and a DC cut capacitor C3 is connected between both ends of the switching element Q2. A starting capacitor C2 is connected between both ends of the discharge lamp FL. The switching elements Q1 and Q2 are connected to the control circuit 140, and are alternately turned on and off by the control circuit 140 at a high frequency of several tens of kHz.

  When the control circuit 140 turns on the switching element Q1, a current flows through a path passing through the smoothing capacitor C1, the switching element Q1, the ballast choke L1, the discharge lamp FL and the starting capacitor C2, the direct current cut capacitor C3, and the smoothing capacitor C1. . On the other hand, when the control circuit 140 turns on the switching element Q2, the DC cutting capacitor C3 is used as a power source, the DC cutting capacitor C3 → the discharge lamp FL and the starting capacitor C2 → the ballast choke L1 → the switching element Q2 → DC cutting. Current flows in a path through the capacitor C3. High-frequency power is supplied from the inverter circuit 130 to the discharge lamp FL when current flows alternately in both paths.

  Hereinafter, the control circuit 140 will be described.

  A dimming signal from the dimmer 200 is input to the control circuit 140. Based on this dimming signal, the control circuit 140 changes the operating frequency of the switching elements Q1, Q2 so that the light output of the discharge lamp FL can be adjusted. The control circuit 140 receives the voltage output from the detection circuit 131, and stops the oscillation of the inverter circuit 130 when this voltage is higher than a preset protection voltage.

  Hereinafter, the detection circuit 131 of the inverter circuit 130 will be described.

  Before describing the detection circuit 131 according to the present embodiment, the detection circuit 131a according to Comparative Example 1 and the detection circuit 131b according to Comparative Example 2 will be described. The detection circuits 131a and 131b according to Comparative Examples 1 and 2 can be incorporated in the discharge lamp lighting device 101 shown in FIG. 2 instead of the detection circuit 131 according to the present embodiment.

  FIG. 3 is a circuit diagram illustrating a configuration of the detection circuit 131a according to the first comparative example.

  In FIG. 3, the detection circuit 131a is connected to the A terminal connected to the source terminal of the switching element Q2, the B terminal connected to the low potential side (ground) of the rectifier DB, and the control circuit 140 to generate the generated voltage. Is provided to the control circuit 140. In Comparative Example 1, the C terminal shown in FIG. 2 is not necessary.

  The detection circuit 131a has a resistor R3 having one end connected to the A terminal and the other end connected to the B terminal, resistors R4 and R5 connected in parallel to the resistor R3, and a capacitor connected in parallel to the resistor R5. C4.

  The detection circuit 131a divides the voltage corresponding to the current flowing through the switching element Q2 (the voltage generated when the current flows through the resistor R3) by the resistors R4 and R5, and outputs the divided voltage to the control circuit 140. A capacitor C4 connected in parallel to the resistor R5 is a noise removing capacitor.

  The control circuit 140 determines whether the voltage divided by the resistors R4 and R5 exceeds the protection voltage. In Comparative Example 1, when the resistors R3, R4, and R5 are selected so that the voltage divided by the resistors R4 and R5 does not exceed the protective voltage when the discharge lamp FL is fully lit, the light from the dimmer 200 is adjusted. Even if the output of the inverter circuit 130 is changed by the signal, the protection voltage does not change, and the voltage divided by the resistors R4 and R5 when the discharge lamp FL is dimmed (the detection output from the D terminal of the detection circuit 131a). Since the voltage on the positive side of the voltage) exceeds the protection voltage Vth1 (see No. 1 in FIG. 6 described later), the control circuit 140 performs a protection operation. In addition, when the resistors R3, R4, and R5 are selected so that the voltage divided by the resistors R4 and R5 does not exceed the protection voltage when the discharge lamp FL is dimmed, the resistance is reduced when the discharge lamp FL is fully lit. Since the voltage divided by R4 and R5 exceeds the protection voltage Vth2 (see No. 2 in FIG. 6 described later), the control circuit 140 similarly performs the protection operation.

  As described above, Comparative Example 1 has a problem that an erroneous determination of whether or not a protective operation is necessary occurs.

  FIG. 4 is a circuit diagram illustrating a configuration of the detection circuit 131b according to the second comparative example. Note that the circuit configuration shown in FIG. 4 is the same as the circuit configuration shown in FIG.

  4, the detection circuit 131b is connected to the control circuit 140 in addition to the A terminal, the B terminal, and the D terminal similar to the detection circuit 131a according to the comparative example 1, and the dimming command value voltage from the control circuit 140 is An input C terminal is provided. In Comparative Example 2, unlike Comparative Example 1 and the present embodiment, the control circuit 140 outputs a dimming command value voltage corresponding to the dimming signal to the detection circuit 131b.

  In addition to the resistors R3, R4, and R5 and the capacitor C4 similar to those of the detector circuit 131a according to Comparative Example 1, the detector circuit 131b includes a resistor R6 having one end connected to the connection point of the resistors R4 and R5, and the resistor R6. A transistor Q4 having a collector terminal connected to the end, a resistor R7 connected between the base terminal and the emitter terminal of the transistor Q4, one end connected to the base terminal of the transistor Q4, and the other end connected to the C terminal A resistor R8 and a capacitor C5 having one end connected to the C terminal and the other end connected to the B terminal are provided.

  The capacitor C5 is a capacitor for removing a noise component of the dimming command value voltage (C terminal) output from the control circuit 140. The resistors R7 and R8 are resistors that divide the dimming command value voltage.

  Similar to the detection circuit 131a according to the comparative example 1, the resistor R3 is connected between the source terminal (A terminal) of the switching element Q2 of the inverter circuit 130 and the ground (B terminal), and the current of the inverter circuit 130 is converted into a voltage. Convert to A series circuit of resistors R4 and R5 for dividing the voltage of the inverter circuit 130 is connected in parallel with the resistor R3. A noise removing capacitor C4 is connected to both ends of the resistor R5.

  The base terminal of the transistor Q4 used as a switch for changing the output characteristic of the detection voltage according to the dimming command value voltage is connected between the resistors R7 and R8. The emitter terminal of the transistor Q4 is connected to the ground. The collector terminal of transistor Q4 is connected to one end of resistor R6. The other end of the resistor R6 is connected to a connection point between the resistors R4 and R5 and the noise removing capacitor C4.

  The maximum value of the voltage applied to the resistor R3 is higher during dimming than when the discharge lamp FL is fully lit. This is due to the fact that the discharge lamp FL has negative resistance characteristics. At the time of dimming (for example, at 25% dimming), the lamp current is smaller and the lamp voltage is higher than when all the lights are on. In order to obtain a voltage for maintaining the discharge of the discharge lamp FL, a larger reactive current flows through the starting capacitor C2 connected in parallel with the discharge lamp FL during dimming than during all-light lighting. For this reason, the current flowing through the resistor R3 increases, and the maximum value of the voltage generated at the resistor R3 increases.

  In the following description, as an example, two-stage dimming of all-light lighting (100% lighting) and 25% dimming is assumed.

  When a dimming signal (100% dimming degree signal) commanding all-light lighting is output from the dimmer 200, the control circuit 140 generates an L-level dimming command value voltage, and the C of the detection circuit 131b. Output to the terminal. In the detection circuit 131b, when this L level dimming command value voltage is input, the transistor Q4 is turned off, and the voltage output from the D terminal is determined by the voltage dividing ratio of the resistors R4 and R5.

  On the other hand, when a dimming signal (25% dimming degree signal) for instructing 25% dimming is output from the dimmer 200, the control circuit 140 generates an H level dimming command value voltage (change command signal). And output to the C terminal of the detection circuit 131b. As described above, in Comparative Example 2, the control circuit 140 outputs the change command signal only when the specific dimming signal (25% dimming degree signal) is received from the dimmer 200. In the detection circuit 131b to which this change command signal is input from the C terminal, the transistor Q4 is turned on and the resistors R5 and R6 are connected in parallel. Therefore, the voltage output from the D terminal is determined by the voltage division ratio between the resistor R4 and the parallel connection resistors of the resistors R5 and R6. The resistance value of the resistor R6 is selected so that the detection voltage output from the D terminal during 25% dimming is substantially the same as the detection voltage output from the D terminal during all-light lighting.

  The control circuit 140 determines that the discharge lamp FL is at the end of its life when the positive voltage of the detection voltage output from the detection circuit 131b is higher than the preset protection voltage Vth1. In addition, the control circuit 140 has a problem that air enters the discharge lamp FL due to the slow leak when the negative voltage of the detection voltage output from the detection circuit 131b is lower than the preset protection voltage Vth2. Judge that In any case, the control circuit 140 stops switching of the switching elements Q1 and Q2 of the inverter circuit 130. Thereafter, the control circuit 140 continues to stop switching of the switching elements Q1, Q2 until the AC power supply Vac is shut off or until the discharge lamp FL is replaced.

  As described above, in Comparative Example 2, the control circuit 140 outputs the dimming command value voltage corresponding to the dimming signal from the outside (the dimmer 200) to the detection circuit 131b. Thus, the detection voltages output from the detection circuit 131b can be made substantially the same. As a result, “state where lamp is dimmed” is mistakenly determined as “end-of-life state”, and “state where lamp is fully lit” is “state where air enters the lamp due to slow leak, etc. It is possible to prevent erroneous determination as “occurred state”. However, the comparative example 2 has a problem that the circuit configuration is complicated and the circuit loss becomes large, for example, the detection circuit 131b requires a dimming command value voltage receiving circuit.

  FIG. 5 is a circuit diagram showing a configuration example of the detection circuit 131 according to the present embodiment.

  In FIG. 5, the detection circuit 131 is similar to the detection circuit 131a according to the comparative example 1, and the A terminal connected to the source terminal of the switching element Q2 and the B terminal connected to the low potential side (ground) of the rectifier DB. And a D terminal connected to the control circuit 140 and outputting the generated voltage to the control circuit 140. Also in this embodiment, the C terminal shown in FIG. 2 is unnecessary.

  The detection circuit 131 includes a resistor R3 having one end connected to the A terminal and the other end connected to the B terminal, resistors R4 and R5 connected in parallel to the resistor R3, and an anode terminal connected to the resistors R4 and R5. The diode D2a is connected to the point, the cathode terminal is connected to the D terminal, the anode terminal is connected to the D terminal, and the diode D2b is connected to the connection point of the resistors R3 and R4.

  The detection circuit 131 divides the positive voltage generated by the current flowing through the resistor R3 by the resistors R4 and R5, and outputs the divided voltage to the control circuit 140. On the other hand, the detection circuit 131 outputs to the control circuit 140 the voltage on the negative side of the voltage generated by the current flowing through the resistor R3 without being divided. As described above, in the present embodiment, the detection circuit 131 does not divide the voltage on the negative side of the detection voltage, but divides only the voltage on the positive side of the detection voltage.

  The negative voltage of the detection voltage output from the D terminal is higher when the discharge lamp FL is fully lit than when dimming. This is because the amplitude of the voltage generated in the resistor R3 is smaller when all the lights are on. On the other hand, the positive voltage of the detection voltage output from the D terminal is higher when the discharge lamp FL is dimmed than when all light is lit. This is because the amplitude of the voltage generated in the resistor R3 is larger during dimming. Therefore, the resistance values of the resistors R3, R4, and R5 are 25% (an example of a predetermined dimming rate) when the negative voltage of the voltage output from the D terminal is not higher than the protection voltage Vth2 when all the lights are turned on. ) The voltage on the positive side of the voltage output from the D terminal during dimming is selected so as not to be higher than the protection voltage Vth1. For example, after selecting the resistance value of the resistor R3 so that the negative voltage output from the D terminal is not higher than the protective voltage Vth2 when all the lights are turned on, the resistance values of the resistors R4 and R5 are set to 25%. A method can be employed in which the voltage on the positive side of the voltage output from the D terminal during dimming is selected so as not to be higher than the protection voltage Vth1.

  The control circuit 140 determines that the discharge lamp FL is at the end of its life when the positive voltage of the detection voltage output from the detection circuit 131 is higher than the preset protection voltage Vth1. In addition, when the negative voltage of the detection voltage output from the detection circuit 131 is higher than the preset protection voltage Vth2, the control circuit 140 has a problem that air enters the discharge lamp FL due to the slow leak. Judge that In any case, the control circuit 140 stops switching of the switching elements Q1 and Q2 of the inverter circuit 130. Thereafter, the control circuit 140 continues to stop switching of the switching elements Q1, Q2 until the AC power supply Vac is shut off or until the discharge lamp FL is replaced.

  FIG. 6 is a diagram illustrating voltage waveforms at the D terminal of the detection circuit 131a according to Comparative Example 1, the detection circuit 131b according to Comparative Example 2, and the detection circuit 131 according to the present embodiment.

  Hereinafter, the difference between the detection voltage output from the D terminals of the detection circuits 131a, 131b, and 131 in the all-light lighting (100% lighting) and 25% dimming will be described with reference to FIG.

  No. Reference numeral 1 denotes a voltage waveform at the D terminal of the detection circuit 131a according to the comparative example 1 when the resistors R3, R4, and R5 are selected so that the control circuit 140 does not perform a protective operation when the discharge lamp FL is turned on. . No. 1, it is possible to prevent erroneous determination of “a state at the end of life” or “a state in which a problem such as air entering the lamp due to a slow leak” occurs only when the discharge lamp FL is turned on all light. When the discharge lamp FL is dimmed by 25%, even if the discharge lamp FL is normal, the positive voltage of the detection voltage output from the D terminal becomes higher than the protection voltage Vth1 indicating “the end of life state” End up.

  No. 2 is a voltage waveform of the D terminal of the detection circuit 131a according to the comparative example 1 when the resistors R3, R4, and R5 are selected so that the control circuit 140 does not perform the protective operation when the discharge lamp FL is 25% dimmed. is there. No. 2 can prevent erroneous determination of “a state at the end of life” or “a state in which a problem such as air entering the lamp due to a slow leak” occurs only when the discharge lamp FL is dimmed by 25%. When the discharge lamp FL is turned on all the time, even if the discharge lamp FL is normal, the negative voltage of the detection voltage output from the D terminal is “the occurrence of a problem such as air entering the lamp due to the slow leak” It becomes higher than the protection voltage Vth <b> 2 indicating “the state that has been performed”.

  No. 3 is a voltage waveform of the D terminal of the detection circuit 131b according to the second comparative example. No. 3, the detection voltages output from the D terminal in both the state in which the discharge lamp FL is turned on all light and the state in which the light is dimmed by 25% are substantially the same. However, as described above, since a circuit configuration for changing the output characteristics of the detection voltage in accordance with the dimming signal is required, there is a problem that the circuit configuration becomes complicated and the circuit loss increases.

  No. 4 is a voltage waveform of the D terminal of the detection circuit 131 according to the present embodiment. No. 4, the positive voltage of the detection voltage output from the D terminal is No. 4. 2 and the negative voltage of the detection voltage output from the D terminal is No. 2. The resistors R3, R4, and R5 are selected so as to be substantially the same as 1. Therefore, in both the state where the discharge lamp FL is fully lit and the state where the discharge lamp FL is dimmed by 25%, the “end-of-life state” or “the problem of air entering the lamp due to the slow leak” occurred. It is possible to prevent erroneous determination of “state”. No. Therefore, the circuit configuration for changing the output characteristic of the detection voltage in accordance with the dimming signal as in FIG. 3 is not required, so that the circuit configuration is simplified and the circuit loss can be reduced.

  As described above, according to the present embodiment, the voltage on the positive side and the voltage on the negative side of the detection voltage corresponding to the voltage of the discharge lamp FL being lit are divided and output at different ratios. Even if the output characteristics of the detection voltage are not changed in accordance with the dimming signal from the dimmer 200, “the state in which the lamp is dimmed” is erroneously determined as the “end-of-life state”, It can be prevented that the “lighted state” is erroneously determined as “a state in which a problem such as air entering the lamp due to a slow leak has occurred”. In addition, the circuit configuration can be simplified and the circuit loss can be reduced as compared with the technique of changing the output characteristics of the detection voltage in accordance with the dimming signal from the dimmer 200.

  As described above, the present embodiment has been described assuming two steps of dimming of all light (100% lighting) and 25% dimming, but this is an example. For example, when assuming five levels of dimming such as all-light lighting (100% lighting), 80% dimming, 60% dimming, 40% dimming, and 20% dimming, the resistors R3 and R4 shown in FIG. , R5, the negative voltage of the detection voltage is not higher than the protection voltage Vth2 when all the lights are on, and the positive voltage of the detection voltage is 20% (an example of a predetermined dimming rate). May be selected so as not to be higher than the protection voltage Vth1. In this way, when assuming N-stage dimming, the resistance values of the resistors R3, R4, and R5 shown in FIG. 5 are set so that the negative voltage of the detection voltage is not higher than the protection voltage Vth2 when all the lights are turned on. In addition, the voltage on the positive side of the detection voltage may be selected so as not to be higher than the protection voltage Vth1 at the time of dimming at the minimum dimming rate (an example of a predetermined dimming rate).

  Further, the present embodiment can also be applied to a non-dimming type discharge lamp lighting device that is used for a plurality of discharge lamps having different electrical characteristics that do not use a dimming signal.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this embodiment, A various change is possible as needed.

100 lighting system, 101 discharge lamp lighting device, 101a, 101b, 101n lighting device, 110 noise filter, 120 boost chopper circuit, 121 voltage detection circuit, 130 inverter circuit, 131, 131a, 131b detection circuit, 140 control circuit, 200 tone Optical device, C1 smoothing capacitor, C2 starting capacitor, C3 DC cut capacitor, C4, C5, CN capacitor, D1, D2a, D2b diode, DB
Rectifier, FL discharge lamp, L1 ballast choke, L2 inductor, L3 common mode choke, Q1, Q2, Q3 switching element, Q4 transistor, R1, R2, R3, R4, R5, R6, R7, R8 resistor, Vac AC power supply.

Claims (6)

In the discharge lamp lighting device that generates high frequency power by the oscillation operation of the inverter circuit, supplies the generated high frequency power to the discharge lamp and lights the discharge lamp,
A detection circuit for detecting a voltage corresponding to a lamp voltage of the discharge lamp and outputting the detected voltage as a detection voltage, wherein the detection voltage is divided and output at a different ratio between a positive voltage and a negative voltage. Circuit,
The positive voltage and the negative voltage of the detection voltage output from the detection circuit are compared with a predetermined positive protection voltage and a negative protection voltage, and the inverter circuit oscillates according to the comparison result. A discharge lamp lighting device comprising: a control circuit for controlling operation.   The control circuit, when the positive voltage of the detection voltage output from the detection circuit is higher than the positive protection voltage, and when the negative voltage of the detection voltage output from the detection circuit is negative The discharge lamp lighting device according to claim 1, wherein the oscillation operation of the inverter circuit is stopped when the voltage is higher than a protection voltage.   The control circuit receives a dimming signal that commands the dimming rate of the discharge lamp, the positive voltage of the detection voltage output from the detection circuit is equal to or lower than the positive protection voltage, and 3. The discharge lamp lighting device according to claim 2, wherein the inverter circuit is oscillated when a negative voltage of a detection voltage output from the detection circuit is equal to or lower than the negative protection voltage.   In the detection circuit, a negative voltage of a detection voltage corresponding to a lamp voltage of the discharge lamp in a state where a slow leak has occurred and the light is dimmed at a predetermined dimming rate is the negative protective voltage. The negative voltage of the detection voltage corresponding to the lamp voltage of the discharge lamp in a state where the lamp is higher and is in a normal state and in the all-lights state is equal to or lower than the negative protective voltage. 4. The discharge lamp lighting device according to claim 3, wherein the negative voltage is divided.   The detection circuit is in a state in which the detection voltage corresponding to the lamp voltage of the discharge lamp is in a state of end of life and in a state where all the lights are lit, and is higher than the protection voltage on the positive side. The positive side of the detection voltage corresponding to the lamp voltage of the discharge lamp in a state that is dimmed at a predetermined dimming rate is equal to or less than the positive side protection voltage. The discharge lamp lighting device according to claim 3 or 4, wherein the voltage is divided. A discharge lamp lighting device according to any one of claims 1 to 5;
An illumination device comprising: a discharge lamp that is lit by high-frequency power supplied from the discharge lamp lighting device.

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