JP2010177174A - Discharge lamp lighting device and illumination fixture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device by which stabilized continuous dimming operation is carried out without using a feedback control circuit. <P>SOLUTION: In an inverter circuit 22, a DC voltage Vm output from a DC power supply circuit 21 is switched, by switching elements Q1 and Q2 and then converted into a high frequency AC voltage and output. The discharge lamp lighting device 11 turns on a discharge lamp (LAMP), by applying an AC voltage output from the inverter circuit 22 to the LAMP. In an HVIC 24 and an operational frequency setting circuit 25, dimming control of the LAMP is carried out, by setting switching frequencies of Q1 and Q2 with respect to the inverter circuit 22. At this time, by the characteristic curve of current values of the LAMP with respect to the switching frequencies of Q1 and Q2, a region having a plurality of the current values corresponding to the same switching frequency is treated as an operation-inhibited region, and the switching frequencies that does not include the operation-inhibited region are set. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  When the discharge lamp lighting device performs continuous dimming operation, the operation curve and the lamp current characteristic curve are different from each other in the frequency range where the operation frequency is the same value at different lamp current values, and the operation is not performed. There is a problem of becoming stable. Therefore, in the conventional discharge lamp lighting device, the continuous light control operation is performed using the feedback control circuit.

  For example, Patent Document 1 describes that countermeasures against a jump phenomenon are taken using power feedback. For example, Patent Literature 2 and Patent Literature 3 describe that power feedback can be used to automatically adapt to discharge lamps having different rated values, and appropriate lighting can be performed. It is also described that by providing an integrator, a rapid change in brightness (light output) of the discharge lamp due to a change in the reference voltage is suppressed, and the discharge lamp lighting device has excellent comfort during use. Has been.

Japanese Unexamined Patent Publication No. 2000-30887 JP 2000-150184 A JP 2000-150185 A

  Conventionally, when continuous light control operation is performed without using a feedback control circuit or the like, the above-described problems occur. A similar problem occurs when the constants of the feedback control circuit are not appropriate. However, there is a problem that the feedback control circuit is expensive and complicated.

  An object of the present invention is, for example, to provide a discharge lamp lighting device that performs a stable continuous dimming operation without using a feedback control circuit.

  A discharge lamp lighting device according to one aspect of the present invention includes an inverter circuit that converts a DC voltage output from a DC power source into a high-frequency AC voltage by switching with a switching element, and outputs the inverter circuit from the inverter circuit. A discharge lamp lighting device for lighting the discharge lamp by applying an output AC voltage to the discharge lamp, and dimming control of the discharge lamp by setting a switching frequency of the switching element for the inverter circuit A frequency setting unit configured to set a switching frequency not included in the operation prohibited range, with a predetermined range of the switching frequency of the switching element as an operation prohibited range.

  According to one aspect of the present invention, in the discharge lamp lighting device, the frequency setting unit that performs dimming control of the discharge lamp by setting the switching frequency of the switching element with respect to the inverter circuit includes the switching frequency of the switching element. Since the switching frequency not included in the operation prohibition range is set with the predetermined range as the operation prohibition range, stable continuous dimming operation can be performed without using a feedback control circuit.

1 is a block diagram illustrating a configuration of a lighting fixture according to Embodiment 1. FIG. 1 is a circuit diagram showing a configuration of a discharge lamp lighting device according to Embodiment 1. FIG. 4 is a graph showing a characteristic curve of the discharge lamp lighting device according to Embodiment 1. FIG. 3 is a circuit diagram showing a configuration example of an operating frequency setting circuit according to the first embodiment. It is a circuit diagram which shows the structure of the discharge lamp lighting device provided with the feedback control circuit. It is a circuit diagram which shows the structural example of the operating frequency setting circuit of a discharge lamp lighting device provided with the feedback control circuit, and a feedback control circuit. 3 is an equivalent circuit of the circuit shown in FIG.

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

Embodiment 1 FIG.
FIG. 1 is a block diagram illustrating a configuration of a lighting fixture 10 according to the present embodiment.

  In FIG. 1, the luminaire 10 includes a discharge lamp lighting device 11, a power supply terminal block 12 connected to the discharge lamp lighting device 11, and a lamp socket 13. The power terminal block 12 is connected to a power line 15 connected to an external commercial power source 14. A discharge lamp (not shown) is attached to the lamp socket 13. The discharge lamp lighting device 11 is powered by a commercial power supply 14 through a power terminal block 12 and performs lighting control and dimming control of a discharge lamp attached to the lamp socket 13.

  FIG. 2 is a circuit diagram showing a configuration of the discharge lamp lighting device 11 according to the present embodiment.

  In FIG. 2, the discharge lamp lighting device 11 includes a DC power supply circuit 21, an inverter circuit 22, a load circuit 23, an HVIC 24 (high voltage integrated circuit), and an operating frequency setting circuit 25.

  The DC power supply circuit 21 includes a rectifier circuit (for example, a diode bridge), a boost chopper circuit, and the like. The rectifier circuit rectifies the AC voltage of the commercial power supply 14, converts it to a DC voltage, and outputs it. The boost chopper circuit boosts and outputs a DC voltage output from the rectifier circuit. In the figure, Vm represents the output voltage of the boost chopper circuit.

  The inverter circuit 22 includes a switching element. In the figure, Q1 and Q2 represent switching MOS-FETs. The switching MOS-FET is an example of a switching element. The inverter circuit 22 converts the output voltage Vm of the step-up chopper circuit into a high-frequency AC voltage and outputs it by repeating ON / OFF of Q1 and Q2.

  The load circuit 23 includes a ballast choke, a starting capacitor, and a coupling capacitor. In the figure, L represents a ballast choke, C represents a starting capacitor, and Cc represents a coupling capacitor. A discharge lamp is connected to the load circuit 23, and the discharge lamp is turned on by a high-frequency AC voltage output from the inverter circuit 22. In the figure, LAMP represents a discharge lamp.

  The HVIC 24 commands the operating frequency (the switching frequency for switching between Q1 and Q2 and the lighting frequency for lighting LAMP) to operate the inverter circuit 22 to Q1 and Q2 of the inverter circuit 22. The inverter circuit 22 supplies a high frequency AC voltage to the load circuit 23 to light up LAMP. Further, the operating frequency is changed in accordance with a command from the HVIC 24 to control the brightness of the LAMP (that is, the LAMP dimming control is performed). In the figure, Vcc is a power supply for the HVIC 24 and Rc is a resistor for monitoring the load current of the load circuit 23.

  Here, with respect to the discharge lamp lighting device 11, a characteristic curve (characteristic curve) of the operating frequency and the lamp current as shown in FIG. 3 can be drawn. In FIG. 3, when the operating frequency becomes higher than a certain level, there are a plurality of lamp current values for the same operating frequency.

  The operating frequency setting circuit 25 sets an operating frequency range in which a plurality of lamp current values exist at the same operating frequency in the above characteristic curve as an operation prohibiting range so that the inverter circuit 22 does not operate, and a plurality of lamp currents at the same operating frequency. The operating frequency range that is less than the minimum value of the operating frequency range in which the value exists is set as the operating range in which the inverter circuit 22 operates. As will be described later, when the operating frequency setting circuit 25 receives a dimming command from outside, the operating frequency setting circuit 25 controls the operating frequency that the HVIC 24 commands the Q1 and Q2 of the inverter circuit 22 within the operating range in accordance with the dimming command.

  As described above, in the present embodiment, the inverter circuit 22 switches the DC voltage (Vm) output from the DC power supply (DC power supply circuit 21) with the switching elements (Q1 and Q2), thereby generating a high-frequency AC voltage. Convert to and output. The discharge lamp lighting device 11 lights the discharge lamp (LAMP) by applying an AC voltage output from the inverter circuit 22 to the discharge lamp (LAMP). The frequency setting unit (HVIC 24 and operating frequency setting circuit 25) performs dimming control of the discharge lamp (LAMP) by setting the switching frequency of the switching elements (Q1 and Q2) to the inverter circuit 22. At this time, the frequency setting unit (HVIC 24 and operating frequency setting circuit 25) sets a switching frequency that is not included in the operation prohibition range, with the predetermined range of the switching frequency of the switching elements (Q1 and Q2) as the operation prohibition range. For example, as shown in FIG. 3, the predetermined range is a characteristic curve of the current value of the discharge lamp (LAMP) with respect to the switching frequency of the switching elements (Q1 and Q2), and there are a plurality of current values corresponding to the same switching frequency. It is an existing range.

  In the present embodiment, the frequency setting unit (HVIC 24 and operating frequency setting circuit 25) sets the switching frequency included in the operating range, with the operating range being less than the minimum value of the operating prohibited range. In this case, for example, as shown in FIG. 3, the operating range is a current value corresponding to the same switching frequency in the characteristic curve of the current value of the discharge lamp (LAMP) with respect to the switching frequency of the switching elements (Q1 and Q2). Is in a range less than the minimum value of the switching frequency.

  According to the present embodiment, since the discharge lamp lighting device 11 includes the frequency setting unit as described above, it is possible to perform a stable continuous dimming operation without using a feedback control circuit.

  FIG. 4 is a circuit diagram showing a configuration example of the operating frequency setting circuit 25 shown in FIG.

  4, the operating frequency setting circuit 25 includes resistors R2, R3,..., Rn that are turned on / off by switches SW2, SW3,. R1 and R2, R3,..., Rn are all fixed resistors. Based on the capacitance of C1 and the combined resistance Rs of R1, R2, R3,..., Rn, the operating frequency fop is, for example, operating frequency fo = 1.41 / (Rs × C1) in the HVIC 24. Determined. For this reason, the operating frequency setting circuit 25 changes the operating frequency by controlling Rs by turning on / off SW2, SW3,..., SWn by the dimming command voltage input from the dimming command circuit 31. , Perform dimming operation. As described above, the range in which the operating frequency setting circuit 25 changes the operating frequency is the operating range shown in FIG. The dimming command circuit 31 may be included in the discharge lamp lighting device 11 or may be included in another device included in the lighting fixture 10. The dimming command circuit 31 receives a dimming signal from a dimmer mounted on a lighting control device or the like, and applies a dimming command voltage corresponding to the dimming signal to SW2, SW3,.

  In the above example, R1 and R2, R3,..., Rn are all fixed resistors, but R1 may be a variable resistor. In this case, SW2, SW3,..., SWn, and R2, R3,.

  Below, the discharge lamp lighting device 11 which concerns on this Embodiment and the discharge lamp lighting device provided with the feedback control circuit are contrasted.

  FIG. 5 is a circuit diagram showing a configuration of a discharge lamp lighting device 81 including a feedback control circuit.

  In FIG. 5, the discharge lamp lighting device 81 includes a DC power supply circuit 91, an inverter circuit 92, a load circuit 93, an HVIC 94, and an operating frequency setting circuit 95, as in the discharge lamp lighting device 11 shown in FIG. A circuit 96 (feedback control circuit) is provided.

  FIG. 6A is a circuit diagram showing a configuration example of the operating frequency setting circuit 95 shown in FIG. FIG. 6B is a circuit diagram showing a configuration example of the FB circuit 96 shown in FIG.

  In FIG. 6A, the operating frequency setting circuit 95 includes a capacitor C1, resistors R1 and R2, and a diode D1. 6B, the FB circuit 96 includes a capacitor C2, a resistor R3, and an operational amplifier 97. The dimming command circuit 31 receives the dimming signal from the dimmer mounted on the illumination control device or the like, and supplies the dimming command voltage corresponding to the dimming signal to the operational amplifier 97, as shown in FIG. Apply to inverting terminal input (IN +). A voltage sensed by Rc for monitoring the load current is applied to the non-inverting terminal input (IN−) of the operational amplifier 97. The operational amplifier 97 changes the output voltage (hereinafter referred to as Vout) so that the voltage (control amount) of the non-inverting terminal (IN−) becomes equal to the voltage (command value) of the inverting terminal (IN +). That is, the operational amplifier 97 adjusts the voltage of the B part based on the dimming command voltage. The C part of the operating frequency setting circuit 95 is connected to the HVIC 94 and serves as a constant voltage source (hereinafter referred to as Vr). The current I1 is I1 = Vr / R1. The current I2 is I2 = (Vr−Vout−Vf) / R2. Here, Vf represents the ON voltage of D1. The operating frequency fop is determined by the HVIC 94 based on I1, I2, the capacity of C1, and Vr, for example, operating frequency fop = (1.41 × (I1 + I2)) / (C1 × Vr). Therefore, the operating frequency setting circuit 95 and the FB circuit 96 control the output voltage from the operational amplifier 97 to change the operating frequency and perform the dimming operation. Since feedback control is performed so that the control amount becomes the command value by the operational amplifier 97, stable light control can be performed against an unexpected change in the control amount. C2 and R3 are used as integrators.

  In the discharge lamp lighting device having the characteristics shown in the graph showing the relationship between the operating frequency and the lamp current in FIG. 3, the dimming operation becomes unstable in the vicinity of the lamp current of 190 mA when feedback control is not performed. Specifically, after a while at a lamp current of 190 mA, LAMP disappears. From the graph, in the characteristic curve of the operating frequency and the lamp current, the operating frequency corresponding to the lamp current of 190 mA is included in the operation prohibited range (specifically, the minimum value of the operation prohibited range). It can be seen that this is because a jump phenomenon has occurred. On the other hand, when feedback control is performed, the above-described problem does not occur up to a lamp current of 10 mA. Further, if the dimming operation is designed in the operating range of the characteristic curve of the operating frequency and the lamp current as in the present embodiment, the above problems do not occur. According to the present embodiment, it is not necessary to use an expensive and complicated feedback control circuit, and stable dimming control can be performed with an inexpensive and simple circuit configuration.

  FIG. 7 is an equivalent circuit of the circuit shown in FIG.

In FIG. 7, V is the supply voltage, L is a ballast choke, C is starting capacitor, I _R is the lamp current, R is the lamp impedance. At this time, the relationship between the operating frequency and the lamp current is as follows.

Assuming that different lamp currents are I _R1 and I _R2 and the paired lamp impedances are R1 and R2 (depending on the lamp voltage-current characteristics), according to the above formula, if the following relationship holds, It can be said that the operating frequency has the same value.

That is, when the above relationship holds, the frequency f (I _R1 , R1) = f (I _R2 , R2).

  For example, as described above, from the relationship between the operating frequency and the lamp current, it is possible to calculate a frequency range (operating range) that is less than the minimum value of the frequencies at which the operating frequency becomes the same value at different lamp current values. In the operating range, the relationship between the operating frequency and the lamp current is a one-to-one relationship.

Embodiment 2. FIG.
In the present embodiment, differences from the first embodiment will be mainly described.

  The characteristic curve of the operating frequency and the lamp current as shown in FIG. 3 varies depending on the temperature, for example. Therefore, in the present embodiment, the discharge lamp lighting device 11 measures the current temperature using the temperature sensor, and the operating frequency of the inverter circuit 22 is based on the operation prohibition range and the operation range that are predefined according to the current temperature. Set.

  Although not shown, the discharge lamp lighting device 11 includes a DC power supply circuit 21, an inverter circuit 22, a load circuit 23, an HVIC 24, and an operating frequency setting circuit 25 as well as the one shown in FIG. A temperature sensor is provided.

  The storage device stores in advance definition data that defines the operation prohibition range and the operation range according to the temperature. The temperature sensor measures the temperature at a predetermined timing (for example, every hour). The frequency setting unit (comprising a microcomputer in addition to the HVIC 24 and the operating frequency setting circuit 25 described above) reads the definition data from the storage device, and operates within the operation inhibition range and the operation range defined by the read definition data. From this, the one corresponding to the temperature measured by the temperature sensor is specified. Then, a switching frequency included in the specified operation range is set (that is, a switching frequency not included in the specified operation prohibition range is set). Thereby, in this Embodiment, more exact light control can be performed.

  DESCRIPTION OF SYMBOLS 10 Lighting fixture, 11 Discharge lamp lighting device, 12 Power supply terminal block, 13 Lamp socket, 14 Commercial power supply, 15 Power line, 21 DC power supply circuit, 22 Inverter circuit, 23 Load circuit, 24 HVIC, 25 Operating frequency setting circuit, 31 adjustment Light command circuit, 81 discharge lamp lighting device, 91 DC power supply circuit, 92 inverter circuit, 93 load circuit, 94 HVIC, 95 operating frequency setting circuit, 96 FB circuit, 97 operational amplifier.

Claims (5)

An inverter circuit that converts a DC voltage output from a DC power source into a high-frequency AC voltage by switching with a switching element and outputs the AC voltage, and applying the AC voltage output from the inverter circuit to the discharge lamp is provided. In a discharge lamp lighting device for lighting a discharge lamp,
A frequency setting unit that performs dimming control of the discharge lamp by setting a switching frequency of the switching element with respect to the inverter circuit, wherein the operation is performed with a predetermined range of the switching frequency of the switching element as an operation prohibition range. A discharge lamp lighting device comprising a frequency setting unit for setting a switching frequency not included in the prohibited range.   The frequency setting unit is characterized in that, in the characteristic curve of the current value of the discharge lamp with respect to the switching frequency of the switching element, a range in which a plurality of current values corresponding to the same switching frequency exist is set as the operation prohibited range. The discharge lamp lighting device according to claim 1.   3. The discharge lamp lighting device according to claim 2, wherein the frequency setting unit sets a switching frequency included in the operation range by setting the operation range to be less than a minimum value of the operation prohibition range. The discharge lamp lighting device further includes:
A storage device for preliminarily storing definition data defining the operation prohibition range according to temperature;
A temperature sensor for measuring the temperature,
The frequency setting unit reads the definition data from the storage device, and sets a switching frequency defined by the read definition data and not included in the operation prohibition range corresponding to the temperature measured by the temperature sensor. The discharge lamp lighting device according to any one of claims 1 to 3. A discharge lamp lighting device according to any one of claims 1 to 4,
A power terminal block connected to the discharge lamp lighting device and connected to an external power line;
A lighting fixture comprising: a lamp socket connected to the discharge lamp lighting device and to which the discharge lamp is attached.

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