JP2006172835A - Discharge lamp lighting device and luminaire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device having fewer parts and making highly precise frequency control. <P>SOLUTION: In this discharge lamp lighting device lighting a discharge lamp La at high frequency with an inverter part 2 provided with a resonance circuit, an integrated circuit 4 for control in the inverter part 2 is provided with: a timer circuit 41 determining time to change to preheating, start up and lighting states by turns; first and second setting circuits 42, 43 setting an operating frequency of the inverter part 2 in the lighting state and the start-up state according to an output current value of a buffer means outputting a constant voltage; a drive circuit 47 inputting signals from the first and second setting circuits 42, 43 and generating driving signals for switching elements Q1, Q2 in the inverter part 2; and a switching circuit 44 switching an output current value of the buffer means in the first or the second setting circuit 42, 43 by switching a plurality of switching devices for control according to an output signal of the timer circuit 41 for setting the operating frequency of the inverter part 2 in the precedence preheating state. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a discharge lamp lighting device for lighting a discharge lamp with high-frequency power and a lighting fixture using the same.

  FIG. 16 shows a basic configuration of a conventional discharge lamp lighting device (Japanese Patent No. 3504876). This discharge lamp lighting device is connected in parallel to a series circuit of switching elements Q1 and Q2 connected to the output end of a DC bus (DC power supply) and the switching element Q2, and mainly includes a resonance inductor L1, a resonance capacitor C1, The load circuit is composed of a discharge lamp La and an integrated circuit 4 ′ that outputs a drive signal to the switching elements Q1 and Q2. A drive signal corresponding to the frequency set in the integrated circuit 4 ′ alternately turns on and off the switching elements Q <b> 1 and Q <b> 2 and converts a DC voltage supplied from the DC bus into a high-frequency voltage. The load circuit lights the discharge lamp La by the high frequency voltage supplied from the series circuit of the switching elements Q1 and Q2 and the resonance action of the resonance inductor L1 and the resonance capacitor C1.

  The internal configuration of the integrated circuit 4 'is shown in FIG. The integrated circuit 4 'includes a drive unit that drives a series circuit of switching elements Q1 and Q2, an oscillator that sets the frequency of the drive signal, and a protection function against abnormal use. Here, the operation of the oscillator that sets the frequency of the drive signal will be mainly described. There are an RT terminal and a CT terminal as terminals of the integrated circuit relating to the frequency setting of the drive signal.

  The built-in oscillator of this integrated circuit is composed of a resistor RT connected between the RT terminal and the ground and a capacitor CT connected between the CT terminal and the ground, like the oscillator found in a general PWM voltage regulator IC. Composed. The voltage of the capacitor CT connected between the CT terminal and the ground has a sawtooth shape as shown in FIG. 18, and the rise of the slope is determined by the current flowing in the RT terminal. Although a specific circuit in the RT terminal is not disclosed, it is a voltage controlled current source and is controlled to be about 2.0 V. Therefore, the output current of a constant voltage buffer circuit generally configured by an operational amplifier is used. If the configuration is such that it is converted by a mirror circuit or the like, the value of the current flowing through the CT terminal can be set, and the rising slope of the voltage of the capacitor CT connected between the CT terminal and the ground can be determined. The falling slope of the voltage of the capacitor CT connected between the CT terminal and the ground is determined by the resistor 18 connected between the DT terminal and the CT terminal.

Therefore, the oscillation frequency of the oscillator is obtained as follows.
f = 1 / {2 × (RT × CT + td)}

  td is a dead time determined by the resistor 18 connected between the DT terminal and the CT terminal. The voltage signal of the capacitor CT connected between the CT terminal and the ground is input to a comparator inside the integrated circuit, and is compared with a threshold value of 2.0 V and a threshold value of 4.0 V, and according to the output of the comparator. By controlling the DT terminal, a sawtooth waveform is obtained, and a signal via the SR latch circuit is output to the drive circuit, and a drive signal is output from the drive signal output terminals HO and LO.

  Furthermore, there is a RUN terminal as a terminal of the integrated circuit involved when the discharge lamp is turned on. In this terminal, an n-channel MOS FEF, which is a control switch element 32, is built in an open drain and is in an ON state when lit. Since the resistor 34 is connected between the RT terminal and the RUN terminal, the above-described resistor RT and the resistor 34 are connected in parallel when the control switch element 32 built in the RUN terminal is turned on. . If the combined resistance value of the resistor RT and the resistor 34 is used, the lighting frequency can be obtained from the above formula.

Furthermore, as control generally performed as illumination control, timer control that sequentially switches between a preheating mode in which the filament of the discharge lamp is preheated before the discharge lamp is lit and a starting mode in which a starting voltage is applied to the discharge lamp is known. ing. In this example, the preheating time is determined by the capacitor 24 connected between the CPH terminal and the ground. The internal circuit of the CPH terminal incorporates a 1.0 μA current source, and the capacitor 24 is charged with a current supplied from the current source. Since the charging voltage of the capacitor 24 is compared with the threshold value of 4.0 V inside the integrated circuit, the preheating time tph is expressed as tph = C24 × 4.0 × 10 ⁶ .

  When the charging voltage of the capacitor 24 is less than 4.0 V, that is, in the preceding preheating state, the frequency during the preceding preheating is determined by the resistor 16 connected between the RPH terminal and the RT terminal of the integrated circuit. In the terminal of the RPH terminal, an n-channel MOS FEF which is a control switch element 26 is built in an open drain, and is in an ON state at the time of pre-heating, that is, when the charging voltage of the capacitor 24 is less than 4.0V. Therefore, the resistor RT and the resistor 16 are connected in parallel, and if the combined resistance value of the resistor RT and the resistor 16 is used, the frequency at the preceding preheating can be obtained from the above formula, and the CT terminal is connected to the CT terminal. It can be seen that the generated sawtooth voltage frequency is kept constant.

  Next, when the charging voltage of the capacitor 24> 4.0 V, the control switch element 26 in the RPH terminal is turned off. Since the capacitor 28 is connected between the RPH terminal and the ground, the current flowing through the RT terminal changes exponentially. That is, the frequency also changes exponentially, that is, continuously with a slope. When a sufficient voltage for starting the discharge lamp La is generated by this frequency change and resonance action, the discharge lamp La is started and lit.

  The voltage of the capacitor 24 is continuously charged by a 1.0 μA current source in the integrated circuit. When the voltage reaches 5.1 V, the control switch element 32 built in the RUN terminal is turned on as described above. Therefore, it operates at the frequency when it is lit.

As described above, in this conventional example, the integrated circuit that controls the discharge lamp lighting device includes a current source controlled to a constant voltage, and is connected between the output terminal of the current source and the ground as an integrated circuit connecting component. The integrated circuit includes an oscillator that has a terminal for connecting the resistor RT and the capacitor CT, and generates a predetermined oscillation frequency by flowing a charging current corresponding to the current flowing through the resistor RT to the capacitor CT. In addition, the control switch elements 26 and 32 are turned on and off to vary the current flowing through the current source terminal, and have a sequence control terminal for performing frequency control during pre-heating and frequency control during lighting. The frequency f1 at the time of preceding preheating of the discharge lamp, the frequency f2 at the start, and the frequency f3 at the time of lighting can be controlled as f1> f2 ≦ f3. A discharge lamp lighting device using such an integrated circuit is advantageous in that it can be made compact at a relatively low cost.
Japanese Patent No. 3504876

  Next, problems of the conventional example will be described. The above-described conventional example has an RT terminal for setting a frequency at the time of start-up, an RPH terminal for frequency control at the time of preceding preheating, and a RUN terminal for frequency control at the time of lighting.

  Here, although not shown in FIG. 17, generally, a protection resistor for the purpose of protection against surge voltage breakdown due to static electricity or the like is connected as processing in the terminal of the integrated circuit, and this protection resistance value is the integrated circuit. Although the resistance value varies depending on the internal structure, the shape of the resistor, and differences between manufacturers, a resistor of 1 KΩ or less is generally used. Further, it is generally known that the absolute value of the resistance configured in the integrated circuit has an error of about ± 20%, and the resistance value change due to the temperature effect is remarkably large.

  As described above, since the frequency setting at the time of starting is set by the current source controlled to a constant voltage and the resistor connected between the current source terminal RT and the ground, the connection resistance to the current source >> integrated circuit protection If a resistor is used, the frequency can be set with relatively high accuracy.

  However, at the time of preheating, by turning on the control switch element 26 in the RPH terminal as described above, the resistor 16 connected between the RPH terminal and the RT terminal is connected in parallel between the RT terminal and the ground. The frequency is increased by increasing the discharge current value from the source. Accordingly, as shown in FIG. 19, two terminal protection resistors Resd that are not shown in the circuit diagram of FIG. 17 are inserted in a path for passing a current from the current source in the RT terminal to the external resistor. Further, as a matter of course, the control switch element 26 in the RPH terminal also has an on-voltage corresponding to the value of the flowing current due to the on-time characteristic mainly determined by the element size.

  As described above, since the preheating frequency is controlled by increasing the discharge current value from the current source in the RT terminal, the voltage drop due to the protective resistance Resd in the RT terminal and the RPH terminal increases as the current value increases. The degree of influence increases and the influence of the on-voltage of the control switch element 26 in the RPH terminal also increases, so that the accuracy of the set frequency is greatly deteriorated.

  Therefore, a discharge lamp lighting device using an integrated circuit that performs control as shown in the above-described conventional example requires components for frequency adjustment, a step of adjusting the frequency, and the like.

Furthermore, the conventional example has the following problems.
In the discharge lamp lighting device using the resonance action, as shown in FIG. 20, the frequency is varied in accordance with each of the preheating, starting and lighting operation states, and at the time of starting, the discharge lamp is turned on. Excessive stress is likely to be applied to apply a high voltage. Further, when excessive power is consumed with respect to predetermined power at the time of lighting, the lamp life may be shortened. Therefore, in order to keep the starting stress as low as possible and not impair the lamp life, the frequency control is performed so that the frequency f1 at the time of pre-heating, the frequency f2 at the time of starting, and the frequency f3 at the time of lighting satisfy f1>f2> f3. It is the control that is generally performed.

  However, in the conventional example of Patent Document 1, since the frequency control is performed in the relationship of f1> f2 ≦ f3 as described above, excessive stress is likely to be applied at the time of start-up or the transition to the lighting state is made. In this state, there is a problem that excessive power is supplied to the discharge lamp to impair the lamp life, and there is a possibility that the switching element, the resonance inductor, and the like constituting the inverter circuit are increased in size.

  The present invention has been made in view of these points, and an object of the present invention is to provide a discharge lamp lighting device that can perform frequency control with high precision and fewer parts.

  In the discharge lamp lighting device of the present invention, in order to solve the above problem, as shown in FIG. 1, a DC power supply unit 1 having at least one smoothing capacitor and an output terminal of the DC power supply unit 1 are provided. An inverter unit 2 having a series circuit of two switching elements Q1, Q2 connected in series and alternately turning on and off the switching elements Q1, Q2, an at least one resonance inductor L1, a resonance capacitor C1, And a discharge lamp La, a high frequency voltage output from the inverter unit 2 is input, a load unit 3 that lights the discharge lamp La by a resonance action, and switching elements Q1 and Q2 of the inverter unit 2 at a predetermined frequency. In the discharge lamp lighting device having the control integrated circuit 4 for driving control, the control integrated circuit 4 preheats the filament of the discharge lamp La. A timer circuit 41 for determining a prior preheating state, a starting state for applying a starting voltage to the discharge lamp La, and a state switching time for sequentially switching the discharge lamp La to a lighting state for lighting at a predetermined output; A first setting circuit 42 configured to set an operating frequency of the inverter unit 2 in the lighting state in accordance with an output current value of the first buffer means, and a first voltage circuit that outputs a constant voltage. A second setting circuit 43 configured to set an operating frequency of the inverter unit 2 in the starting state according to an output current value of the second buffer means, and the first setting circuit. 42, having a drive circuit 47 for inputting a signal from the second setting circuit 43 and generating a drive signal to the switching elements Q1 and Q2, and at least two control switch elements; By turning on / off individual control switch elements in accordance with the output signal of the timer circuit 41, the output current value of the first buffer means or the output current value of the second buffer means is switched, and the preceding preheating is performed. And a switch circuit 44 for setting the operating frequency of the inverter unit 2 in the state.

  According to the invention of claim 1, since the frequency setting accuracy does not deteriorate in each operation mode at the time of preliminary preheating, start-up, and lighting, the frequency adjustment component and the step of adjusting the frequency are unnecessary. Become. According to the second aspect of the invention, the control integrated circuit can be further simplified and the same effect can be obtained as compared with the first aspect of the invention. According to the third aspect of the present invention, the control integrated circuit can be further simplified as compared with the first aspect of the present invention, and the current consumption of the control integrated circuit can be reduced. According to the invention of claim 4, the frequency setting accuracy is slightly worse than that of the inventions of claims 1 to 3, but the configuration of the control integrated circuit can be further simplified, and the current consumption of the control integrated circuit is further reduced. Can be reduced. According to the fifth aspect of the present invention, the time of the preceding preheating mode and the start mode can be set with respect to the first to fourth aspects of the invention without deteriorating accuracy due to external factors such as the mounting state.

(Embodiment 1)
FIG. 1 shows a configuration of a discharge lamp lighting device according to Embodiment 1 of the present invention. The basic configuration is almost the same as that of the conventional example, a rectifier DB that rectifies an AC power supply AC, a DC power supply unit 1 that has at least one smoothing capacitor and is connected to an output terminal of the rectifier DB, and the DC power supply unit. 1 is connected to an output end of the inverter unit 2 including a series circuit of switching elements Q1 and Q2 connected in series, and at least one resonance inductor L1, resonance capacitor C1, DC cut capacitor C2, and discharge lamp La. A load unit 3 for inputting a high-frequency voltage output from the inverter unit 2 by alternately turning on and off the switching elements Q1 and Q2, and lighting the discharge lamp La by a resonance action; and an inverter unit 2 or a load A control power supply circuit 5 connected to any part of the unit 3 and supplying a control power supply to a control integrated circuit 4 to be described later, and the switch A drive signal output terminals which can be directly turned on and off driving the ring element Q1, Q2, and a control integrated circuit 4 constituting one integrated circuit.

  The control integrated circuit 4 is in a predetermined time to a pre-heating mode for pre-heating the filament of the discharge lamp La, a starting mode for applying a starting voltage to the discharge lamp La, and a lighting mode for lighting the discharge lamp La with a predetermined light output. A timer circuit 41 that sequentially switches, a lighting frequency setting circuit 42 that determines an inverter operating frequency in the lighting mode according to the output of the timer circuit 41, and an inverter operation in the start mode according to the output of the timer circuit 41 A start frequency setting circuit 43 for determining a frequency and a plurality of control switch elements that are turned on and off according to the output of the timer circuit 41, and a switch circuit for determining an inverter operating frequency in the preceding preheating mode by performing an on / off operation 44 and a frequency corresponding to the signal from the lighting frequency setting circuit 42 and the starting frequency setting circuit 43. A signal conversion circuit 45 that generates a signal, and a reference power supply that receives a supply voltage from the control power supply circuit 5, generates a predetermined constant voltage, and supplies a stable reference power supply to each circuit in the control integrated circuit 4. The drive signal output from the drive signal output terminal is output from the signal generated by the signal conversion circuit 45 via the drive circuit 47.

  Next, the specific configuration and operation of the control integrated circuit 4 will be described with reference to the specific circuit diagram of FIG. 2 and the timing chart of FIG. The specific circuit shown in FIG. 2 illustrates the specific configuration of the lighting frequency setting circuit 42, the starting frequency setting circuit 43, the switch circuit 44, and the signal conversion circuit 45 in the control integrated circuit 4.

  The lighting frequency setting circuit 42 has a buffer circuit configuration mainly including an operational amplifier OP1, an npn transistor Tr1 connected to the output of the operational amplifier OP1, and a resistor Rosc1 connected between the emitter and ground of the transistor. In this circuit, a constant voltage substantially equal to the threshold voltage Vth3 input to the + side input terminal of OP1 is generated on the emitter side of the transistor Tr1.

  The starting frequency setting circuit 43 has a buffer circuit configuration mainly composed of an operational amplifier OP2, an npn transistor Tr2 connected to the output of the operational amplifier OP2, and a resistor Rosc2 connected between the emitter and ground of the transistor. In this circuit, a constant voltage substantially equal to the threshold voltage Vth4 input to the + side input terminal of OP2 is generated on the emitter side of the transistor Tr2.

  The signal conversion circuit 45 includes a lighting frequency setting circuit 42 and mirror circuits M1, M2, and M3 that convert the current flowing to the starting frequency setting circuit 43 at a predetermined ratio. Further, a comparator CP1 that compares the voltage of the capacitor Cpls with a threshold value Vth1 or Vth2 set in the transfer gate circuit, and a control switch element SW1 that is turned on / off according to the output signal of the comparator CP1 are provided. ing. When the control switch element SW1 is off, the capacitor Cpls is discharged with a constant current sunk to the mirror circuit M3. When the control switch element SW1 is on, the mirror circuit M3 is derived from the constant current sourced from the mirror circuit M2. Capacitor Cpls is charged with a current obtained by subtracting a constant current that is sinked to. The signal conversion circuit 45 periodically switches between the charging and discharging according to the output of the comparator CP1 and outputs a periodic signal equal to the charging / discharging period, that is, a frequency signal to the drive circuit 47.

  The switch circuit 44 is connected between the control switch element SW2 connected between the base and ground of the transistor Tr1 constituting the lighting frequency setting circuit 42 and between the base and ground of the transistor Tr2 constituting the starting frequency setting circuit 43. Control switch element SW3, the control switch element SW6 connected between the collector of the transistor Tr1 constituting the lighting frequency setting circuit 42 and the mirror circuit M1, and between the gate and ground of the control switch element SW6 , A control switch element SW4 connected between the collector of the transistor Tr2 constituting the starting frequency setting circuit 43 and the mirror circuit M1, and a gate of the control switch element SW7. Control switch connected between ground And a child SW5.

  The timer circuit 41 outputs an on / off signal to each element of the switch circuit 44. The reference power supply circuit 46 supplies stable control power to each of the circuits.

  Detailed operation will be described with reference to the timing chart of FIG. First, by starting the supply of control power to the control integrated circuit 4, the reference power output from the reference power circuit 46 rises and the timer circuit 41 starts operating. The detailed configuration and operation of the timer circuit 41 will be described later with reference to FIGS. 4 and 5. A CLOCK signal having a constant period shown in the timing chart is generated inside the timer circuit 41, and this constant period signal is used as a counter circuit. , The OUT1, OUT2, OUT3, and OUT4 signals output from the timer circuit 41 are generated by inputting the logic circuit including an RS latch circuit.

  The OUT1 signal and OUT2 signal output from the timer circuit 41 are respectively input to the gates of the control switch elements SW2 and SW3 constituting the switch circuit 44. After the CLOCK signal starts oscillating, the OUT1 signal and the OUT2 signal become “H” and then become “L” for one period of the CLOCK signal.

  When the OUT1 signal and the OUT2 signal are “H”, the base currents of the transistors Tr1 and Tr2 cannot be supplied, so that the emitter voltages of the transistors Tr1 and Tr2, that is, the output voltage of the buffer circuit are approximately 0V. That is, since the current flowing through the resistor Rosc1 and the resistor Rosc2 is also approximately 0A, the current flowing through the mirror circuit is also 0A, and the charge / discharge operation of the capacitor Cpls is not performed, so the drive circuit 47 does not oscillate.

  Here, the stop state at the initial stage of the start-up sequence is an operation that does not exist in the conventional example. When the same operation as in the conventional example is realized, the OUT1 signal, the OUT2 signal, and a control switch that is turned on / off by inputting this signal The elements SW2 and SW3 are not necessary.

  When the OUT1 signal and the OUT2 signal are “L”, a base current is supplied to the transistors Tr1 and Tr2 of each of the buffer circuit output stages, and the emitter voltages of the transistors Tr1 and Tr2, that is, the output voltage of the buffer circuit are respectively input. The voltage is substantially equal to the threshold values Vth3 and Vth4.

  Accordingly, since current flows through the resistor Rosc1 and the resistor Rosc2, a charge / discharge current is supplied to the capacitor Cpls via the mirror circuit, and the voltage generated in the capacitor Cpls has a triangular waveform and starts an oscillation operation. A periodic signal equal to the triangular wave period is output to the drive circuit 47, and a drive signal is output from the drive circuit 47 to the inverter unit 2.

  During the pre-heating, the OUT3 signal and the OUT4 signal output from the timer circuit 41 are OUT3 = "H" and OUT4 = "H". The OUT3 signal and the OUT4 signal are respectively input to the gates of the control switch elements SW4 and SW5 of the switch circuit 44, and the control switch elements SW4 and SW5 are turned on. Since the drains of the control switch elements SW4 and SW5 are respectively connected to the gates of the control switch elements SW6 and SW7, which are p-channel MOSFETs, the control switch element SW6 when the control switch elements SW4 and SW5 are turned on. , SW7 is also turned on.

  When the control switch elements SW6 and SW7 are turned on, a current obtained by adding the output currents IRosc1 and IRosc2 of the buffer circuit flows from the mirror circuit M1. At the time of starting, the OUT3 signal and the OUT4 signal output from the timer circuit 41 are OUT3 = “H” and OUT4 = “L”. Accordingly, since the control switch element SW6 constituting the switch circuit 44 is turned off, in this case, the current flowing from the mirror circuit M1 is IRosc2.

  During lighting, the OUT3 signal and the OUT4 signal output from the timer circuit 41 are OUT3 = "L" and OUT4 = "H". Therefore, the control switch element SW6 constituting the switch circuit 44 is turned on and the switch SW7 is turned off. In this case, the current flowing from the mirror circuit M1 is IRosc1.

  Therefore, via the mirror circuit, the frequency corresponds to IRosc1 + IRosc2 during preheating, the frequency according to Rosc2 during startup, and the frequency according to Rosc1 during lighting.

  Next, the specific configuration and operation of the timer circuit 41 will be described with reference to the specific circuit of FIG. 4 and the timing chart of FIG. As shown in the specific circuit of FIG. 4, the timer oscillation circuit 412 constituting the specific circuit has the same configuration as the lighting frequency setting circuit 42 and the signal conversion circuit 45 described above, and performs charge / discharge operation on the capacitor Ctim. By doing so, the basic clock signal of the timer circuit 41 is generated.

  The charge / discharge operation for the capacitor Ctim is switched by inputting a signal output from the comparator CP2 to the gate of the control switch element SW8 and turning on / off the control switch element SW8. The output signal of the comparator CP2 becomes the output of the timer oscillation circuit 412, and becomes the basic clock signal for operating the logic circuit at the subsequent stage. In general, the preceding preheating time requires about 1 second, and as shown in FIG. 5, the timer oscillation output, which is a basic clock signal, has a period of four periods as the preceding preheating time. Therefore, the period of the timer oscillation output in this example is about 250 msec.

  This timer oscillation output is input to the counter circuit 413. As shown in FIG. 4, by combining count elements CNT1 to CNT3, flip-flops RSFF1 to RSFF2, INV elements, AND elements, etc., signals as shown in the timing chart of FIG. OUT1 to OUT4 shown in FIG.

  Here, the setting of the preceding preheating time in the conventional example has already been described, but in the conventional example, the time is set by charging the capacitor 24 with a current of 1 μA, so that a preceding preheating time of about 1 second is obtained. Requires a capacitor capacity of about 0.24 μF.

  In this example, if the capacitor Ctim for setting the basic clock signal cycle is similarly a 0.24 μF capacitor, and the triangular wave generated in Ctim has an amplitude between 1V and 4V, the capacitor Ctim The charge / discharge current is calculated to be a current value of about 5.8 μA, and the preceding preheating time can be set with a current value about six times that of the conventional example.

  When the integrated circuit and components connected to the terminals of the integrated circuit are mounted in the device, leakage current from the high-voltage generator, leakage current of the component itself, and leakage current value due to temperature change depending on the mounting arrangement (In general, leakage current tends to increase at higher temperatures), and special consideration is required when controlling with a minute current.

  In the present embodiment, the time for the pre-heating or the like is set with a current about six times that of the conventional example, and it can be seen that more accurate control can be performed with respect to the conventional example.

  As described above, in the present embodiment, two buffer circuits that output a constant voltage are provided, and the control switch element is connected so as not to be affected by the voltage drop of the control switch element. Since three types of lighting frequencies are set, it is possible to set the frequency with higher accuracy than the conventional example.

  In addition, the resistors Rosc1 and Rosc2 connected to the output terminals of the two buffer circuits that output constant voltages have been described as being inside the integrated circuit, but are connected to the outside of the integrated circuit as in the conventional example. It is good also as such a structure.

  In this case, the integrated circuit protection resistor Resd is inserted into the terminal portion of the integrated circuit. However, as described in the conventional example, the resistance value (or resistance) of the resistor Rosc1 connected to the output terminal of the buffer circuit is also described. The resistance value of Rosc2) >> If the integrated circuit protection resistor is used, the frequency can be set with relatively high accuracy, so the frequency adjustment parts and processes described above are not required, and a cheaper discharge lamp lighting device is supplied. can do.

  Furthermore, in the present embodiment, since the preheating pre-heating frequency f1, the starting wave number f2, and the lighting wave number f3 are set in a relationship of f1> f2> f3, the switching elements Q1, Q2 constituting the inverter unit 2 and the load There is no fear that excessive stress is applied to the components such as the resonance inductor L1 constituting the portion 3, and these components can be further downsized (current capacity can be reduced), and a more inexpensive discharge lamp lighting device can be realized. Can do. Moreover, since there is no possibility of applying excessive stress to the load portion 3, there is no possibility of impairing the lamp life.

(Embodiment 2)
FIG. 6 shows a specific circuit of the control integrated circuit 4 used in the discharge lamp lighting device according to the second embodiment of the present invention. The basic configuration of the discharge lamp lighting device is the same as that of the first embodiment. The difference in configuration from the first embodiment is that three signals OUT1, OUT2, and OUT3 are output from the timer circuit 41 of the control integrated circuit 4, and the control switch element of the switch circuit 44 according to the OUT3 signal. SW5 and SW7 are turned on and off, and the current IRosc2 output from the buffer circuit of the starting frequency setting circuit 42 is turned on and off.

  Next, the operation of this embodiment will be described with reference to the timing chart of FIG. The timer circuit performs substantially the same operation as in the first embodiment, and outputs signals OUT1, OUT2, and OUT3 as shown in the timing chart. The operation immediately after the rising of the reference power supply is exactly the same as that of the first embodiment. When OUT1 = “L” and OUT2 = “L”, a drive signal is output from the drive circuit, and the operation is performed at the frequency at the preceding preheating.

  At the time of start-up, in this embodiment, a signal that outputs OUT1 = "H" and OUT2 = "L" is output. By setting OUT1 = “H”, as described in the first embodiment, the control switch element SW2 of the switch circuit 44 is turned on and the base current of the npn transistor Tr1 of the lighting frequency setting circuit 42 is not supplied. The emitter voltage of the npn transistor Tr1, that is, the output voltage of the buffer circuit is approximately 0V. Therefore, since the current IRosc1 flowing through the resistor Rosc1 is 0A, the current flowing from the mirror circuit M1 at the start is IRosc2.

  Subsequently, during lighting, a signal with OUT1 = “L” and OUT2 = “H” is output, the control switch element SW3 of the switch circuit 44 is turned on, and the base current of the npn transistor Tr2 of the starting frequency setting circuit 43 is turned on. Will not be supplied. Therefore, since the current IRosc2 flowing through the resistor Rosc2 is 0A, the current flowing from the mirror circuit M1 at the time of lighting is IRosc1.

  By performing the operation as described above, a frequency corresponding to IRosc1 + IRosc2 is obtained at the time of preheating in this example, a frequency corresponding to Rosc2 is set at the start, and a frequency corresponding to Rosc1 is set at the time of lighting.

  In the present embodiment, since the output voltage of one of the two buffer circuits is set to approximately 0 V and the current flowing through the resistors Rosc1 and Rosc2 is set to 0 A at start-up and lighting, the circuit is simplified from that of the first embodiment. The configuration has the same effect as that of the first embodiment.

(Embodiment 3)
FIG. 8 shows a specific circuit of the control integrated circuit 4 used in the discharge lamp lighting device according to the third embodiment of the present invention. The basic configuration of the discharge lamp lighting device is the same as that of the first embodiment. In the present embodiment, as in the second embodiment, three signals OUT1, OUT2, and OUT3 are output from the timer circuit 41 of the control integrated circuit 4. The difference in configuration is that a series circuit of resistors Rosc2 and Rosc3 is connected between the output of the buffer circuit constituting the starting frequency setting circuit 42 and the ground, and the connection point between the resistors Rosc2 and Rosc3 and the control switch element SW5. The drain is connected.

  Next, the operation of the present embodiment will be described using the timing chart of FIG. The timer circuit 41 performs substantially the same operation as in the first and second embodiments, and outputs signals OUT1, OUT2, and OUT3 as shown in the timing chart.

  The operation immediately after the rising of the reference power supply is exactly the same as that of the first embodiment. When OUT1 = “L” and OUT2 = “L”, a drive signal is output from the drive circuit, and the operation is performed at the frequency at the preceding preheating.

  Further, at the time of pre-heating, OUT3 = “H” and the control switch element SW5 of the switch circuit 44 is turned on. Therefore, the current IRosc2 output from the buffer circuit of the starting frequency setting circuit 43 becomes a current IRosc2 'determined by the output voltage of the buffer circuit and the resistor Rosc2.

  At the time of start-up, in this embodiment, OUT1 = “L”, OUT2 = “L”, and OUT3 = “L”. When OUT3 = “L”, the control switch element SW5 of the switch circuit 44 is turned off. Therefore, the current IRosc2 output from the buffer circuit of the starting frequency setting circuit 43 becomes the current IRosc2 ″ determined by the combined resistance of the output voltage of the buffer circuit and the resistors Rosc2 and Rosc3.

  At the time of lighting, in this embodiment, OUT1 = "L" remains, OUT2 = "H", and OUT3 = "L". By setting OUT2 = “H”, the voltage output from the buffer circuit of the starting frequency setting circuit 43 becomes approximately 0V, and the current flowing through the resistors Rosc2 and Rosc3 also becomes 0A.

  By performing the operation as described above, a frequency corresponding to IRosc1 + IRosc2 'is obtained during preheating in the present example, a frequency corresponding to IRosc1 + IRosc2 "at start-up, and a frequency corresponding to Rosc1 during lighting.

  In the present embodiment, of the two buffer circuits at the time of lighting, the output voltage of the buffer circuit of the starting frequency setting circuit 43 is set to approximately 0 V, and at the time of starting, the control switch element SW5 is turned on / off as in the conventional example. The resistance value connected to the buffer circuit output is variable by turning off. However, compared with the conventional example, the present embodiment has two buffer circuits as in the first and second embodiments, and the current output from the mirror circuit M1 is divided into the two buffer circuits, respectively. Therefore, the amount of current change per buffer circuit is considerably lower than that of the conventional example, and can be suppressed to about ½. Therefore, the influence of the ON voltage of the control switch element SW5 is also relatively small.

  Therefore, although the accuracy of frequency setting for each pre-heating, starting, and lighting operation mode is slightly worse than in the first and second embodiments, the accuracy is definitely improved over the conventional example. In addition, during lighting, the voltage output from the buffer circuit of the starting frequency setting circuit 43 is set to approximately 0 V, so that it is possible to reduce excess current consumption of the integrated circuit. Further, as in the first embodiment, the preheating preheating frequency f1, the starting frequency f2, and the lighting frequency f3 are set in a relationship of f1> f2> f3, so that excessive stress is applied as in the conventional example. There is no risk of damaging the lamp life.

(Embodiment 4)
FIG. 10 shows a specific circuit of the control integrated circuit 4 used in the discharge lamp lighting device according to the fourth embodiment of the present invention. The basic configuration of the discharge lamp lighting device is the same as that of the first embodiment. The operation of this embodiment is the same as that of the third embodiment. A difference in configuration from the third embodiment is that a series circuit of resistors Rosc2 and Rosc3 connected to the buffer circuit output end of the starting frequency setting circuit 43 and a resistor connected to the buffer circuit output end of the lighting frequency setting circuit 42 Rosc1 is disposed outside the integrated circuit, the drain of the control switch element SW5 of the switch circuit 44 is used as an integrated circuit terminal, and the drain terminal of the control switch element SW5 is connected to the connection point between the resistors Rosc2 and Rosc3. Is a point. As described above, the protection resistor Resd of the integrated circuit is inserted in the terminal of the integrated circuit.

  Since the operation of this embodiment is the same as that of the third embodiment, when the control switch element SW5 of the switch circuit 44 is on, the frequency setting accuracy deteriorates due to the influence of the protective resistor Resd. However, as described in the third embodiment, this embodiment also has two buffer circuits, and the current output from the mirror circuit is shunted to the two buffer circuits. The current change amount can be kept relatively lower than that of the conventional example.

  Therefore, the accuracy of frequency setting for each pre-heating, start-up, and lighting operation mode is slightly worse than in the first and second embodiments, but the accuracy is definitely improved over the conventional example. Furthermore, the frequency can be set freely by changing the constants of components connected to the outside of the integrated circuit.

(Embodiment 5)
FIG. 11 shows a specific circuit of the control integrated circuit 4 used in the discharge lamp lighting device according to the fifth embodiment of the present invention. The basic configuration of the discharge lamp lighting device is the same as that of the first embodiment. The operation of the present embodiment is the same as that of the third and fourth embodiments. Similarly to the fourth embodiment, the resistor Rosc2 connected to the buffer circuit output terminal of the starting frequency setting circuit 43 and the buffer circuit output terminal of the lighting frequency setting circuit 42 are used. The resistor Rosc1 connected to is disposed outside the integrated circuit, and the drain of the control switch element SW5 of the switch circuit 44 is used as an integrated circuit terminal. The difference from the fourth embodiment is that it is connected to the buffer circuit output terminal of the lighting frequency setting circuit 42 via the resistor Rosc3 arranged outside the integrated circuit, and therefore this embodiment is also equivalent to the fourth embodiment. Has an effect.

(Embodiment 6)
FIG. 12 shows a specific circuit of the timer circuit in the control integrated circuit 4 used in the discharge lamp lighting device according to the sixth embodiment of the present invention. The difference between the present embodiment and the first to fifth embodiments resides in the timer circuit, and only the specific configuration of the timer circuit is illustrated. The configuration of the timer oscillation circuit 412 constituting the timer circuit is almost the same as the configuration of the timer oscillation circuit 412 in the first embodiment. The difference between this embodiment and FIG. 4 shown in Embodiment 1 is the specific configuration of the counter circuit 413 and the period of the basic CLOCK signal generated by the timer oscillation circuit 412.

  Hereinafter, it will be described in detail with reference to the timing chart of FIG. The voltage generated in the capacitor Ctim that determines the period of the basic CLOCK signal is switched by the output signal of the comparator CP2 as in the first embodiment, and the voltage generated in the capacitor Ctim similarly has a triangular waveform. Here, in the first embodiment, the preceding preheating time is about 1 second, the capacitance of the capacitor Ctim is 0.22 μF, and the source sink current to the capacitor Ctim is about 6 μA.

  In recent years, the miniaturization of capacitors has progressed, and compact and large-capacity monolithic ceramic capacitors have also been developed for chip-type components. For example, when the capacitor Ctim = 1.0 μF, in the configuration of the first embodiment, the charge / discharge current to the capacitor Ctim may be about 24 μA. It can be seen that settings can be made.

  On the other hand, as shown in FIG. 12 of the present embodiment, the charging / discharging current value is set so that the charging / discharging time of the capacitor Ctim is different, and the capacitor Ctim oscillates between 1 to 4 V, and the capacitor Ctim = If the charging time at 1.0 μF is 100 msec and the discharging time is 300 msec, the charging current to the capacitor Ctim is 30 μA and the discharging current is 10 μA.

  Therefore, it can be seen that even in the setting as in the present embodiment, it is possible to set the preheating time and the like with a current larger than that in the conventional example and the first embodiment. Furthermore, in the present embodiment, the period of the basic CLOCK signal output from the timer oscillation circuit 412 is 400 msec, so that the count element constituting the counter circuit 413 is composed of two elements CNT1 and CNT2 as shown in FIG. can do.

  In the present embodiment, by setting the period of the basic CLOCK signal to about 400 msec, it is possible to reduce the components constituting the counter circuit, and to realize a smaller and less expensive integrated circuit for control.

(Embodiment 7)
FIG. 14 and FIG. 15 show the configuration of a lighting fixture equipped with the discharge lamp lighting device described in the first to sixth embodiments. In the figure, La1 and La2 are discharge lamps, 6 is a lighting fixture body, and 7 is a discharge lamp lighting device. When the discharge lamp lighting device is mounted on a lighting fixture, the discharge lamp lighting device is leaked from the discharge lamp and the wiring from the discharge lamp lighting device to the discharge lamp due to the leakage of high-frequency current due to the stray capacitance generated between the lighting fixture bodies. In particular, when performing control using a minute current, it is necessary to consider the effect when the lighting fixture is mounted. As described in the first to sixth embodiments, the setting of the preceding preheating time or the like has a circuit configuration in which control is performed with a large current value as compared with the conventional example. There is no possibility that the above-described problem occurs in a lighting fixture equipped with the apparatus.

It is a circuit diagram which shows the whole structure of the discharge lamp lighting device which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows the principal part structure of the integrated circuit for control used for the discharge lamp lighting device which concerns on Embodiment 1 of this invention. 3 is a timing chart showing an operation of the control integrated circuit of FIG. 2. FIG. 3 is a circuit diagram showing a specific internal configuration of a timer circuit in the control integrated circuit of FIG. 2. 3 is a timing chart showing the operation of the timer circuit of FIG. It is a circuit diagram which shows the principal part structure of the integrated circuit for control used for the discharge lamp lighting device which concerns on Embodiment 2 of this invention. 7 is a timing chart showing an operation of the control integrated circuit of FIG. 6. It is a circuit diagram which shows the principal part structure of the integrated circuit for control used for the discharge lamp lighting device which concerns on Embodiment 3 of this invention. FIG. 9 is a timing chart showing an operation of the control integrated circuit of FIG. 8. FIG. It is a circuit diagram which shows the principal part structure of the integrated circuit for control used for the discharge lamp lighting device which concerns on Embodiment 4 of this invention. It is a circuit diagram which shows the principal part structure of the integrated circuit for control used for the discharge lamp lighting device which concerns on Embodiment 5 of this invention. It is a circuit diagram which shows the specific internal structure of the timer circuit in the integrated circuit for control used for the discharge lamp lighting device which concerns on Embodiment 6 of this invention. 13 is a timing chart showing the operation of the timer circuit of FIG. It is a perspective view of the lighting fixture which concerns on Embodiment 7 of this invention. It is a longitudinal cross-sectional view of the lighting fixture of FIG. It is a circuit diagram of the conventional discharge lamp lighting device. It is a circuit diagram of the integrated circuit used for the discharge lamp lighting device of FIG. 18 is a timing chart showing the operation of the integrated circuit of FIG. FIG. 18 is a circuit diagram illustrating a configuration of a main part of the integrated circuit of FIG. 17. It is operation | movement explanatory drawing of the discharge lamp lighting device of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 DC power supply part 2 Inverter part 3 Load part 4 Integrated circuit for control 5 Control power supply circuit

Claims (6)

A DC power supply having at least one smoothing capacitor;
An inverter unit connected to an output end of the DC power supply unit, having a series circuit of two switching elements connected in series, and alternately turning on and off the switching elements;
A load unit that has at least one resonance inductor, a resonance capacitor, and a discharge lamp, inputs a high-frequency voltage output from the inverter unit, and lights the discharge lamp by a resonance action;
In a discharge lamp lighting device comprising a control integrated circuit for driving and controlling the switching element of the inverter unit at a predetermined frequency,
The control integrated circuit includes:
A timer circuit for determining a pre-preheating state for pre-heating the filament of the discharge lamp, a starting state for applying a starting voltage to the discharge lamp, and a state switching time for sequentially switching to a lighting state for lighting the discharge lamp at a predetermined output;
A first setting circuit configured by first buffer means for outputting a constant voltage, and setting an operating frequency of the inverter unit in the lighting state according to an output current value of the first buffer means;
A second setting circuit configured to set the operating frequency of the inverter unit in the starting state in accordance with an output current value of the second buffer means, the second setting circuit including a second buffer means for outputting a constant voltage;
A drive circuit that inputs signals from the first setting circuit and the second setting circuit and generates a drive signal to the switching element;
An output current value of the first buffer means or the second buffer means by having at least two control switch elements and turning on / off individual control switch elements in accordance with an output signal of the timer circuit And a switch circuit for setting an operating frequency of the inverter unit in the preceding preheating state. The first setting circuit in the control integrated circuit includes a first impedance element connected to the output terminal of the first buffer means, and the second setting circuit in the control integrated circuit includes the second setting circuit. A second impedance element connected to the output terminal of the buffer means, and the control integrated circuit generates a frequency according to a current value obtained by adding the current values flowing through the first and second impedance elements. The control switch element further includes a signal conversion means, and shuts off a current path flowing through at least one of the first impedance element and the second impedance element by an on / off operation of the control switch element constituting the switch circuit. The discharge lamp lighting device according to claim 1, wherein: The first setting circuit in the control integrated circuit includes a first impedance element connected to the output terminal of the first buffer means, and the second setting circuit in the control integrated circuit includes the second setting circuit. A second impedance element connected to the output terminal of the buffer means, and the control integrated circuit generates a frequency according to a current value obtained by adding the current values flowing through the first and second impedance elements. And a signal conversion unit, wherein the output voltage of the first buffer unit and the second buffer unit is controlled to be substantially 0 V by an on / off operation of a control switch element constituting the switch circuit. The discharge lamp lighting device according to claim 1 or 2. The control integrated circuit includes at least a first terminal portion which is an output end of the first buffer means, a second terminal portion which is an output end of the second buffer means, and at least the switch circuit. And a third terminal portion which is an output end of one control switch element, and the output voltage value output from the second buffer means when switching from the starting state frequency to the lighting state frequency is approximately 0V. The first impedance element is composed of at least one resistor and is connected to the outside of the control integrated circuit and between the first terminal portion and the ground, and the second impedance element is It is composed of at least one resistor, is connected to the outside of the control integrated circuit and between the second terminal portion and the ground, and the third terminal portion is connected to the outside of the control integrated circuit. The discharge lamp lighting device according to claim 3, characterized in that via an anti-connected to one of said first terminal portion or the second terminal portion. The timer circuit has at least one comparison means, and at least one capacitor is connected to a terminal of the control integrated circuit which is one input terminal of the comparison means, and charging means for charging the capacitor with a substantially constant current; And a discharging means for discharging at a substantially constant current, and periodically switching between the charging means and the discharging means according to the output signal of the comparison means, and the charging / discharging cycle of the capacitor is 250 msec or more and 400 msec or less. The discharge lamp lighting device according to claim 1, wherein the discharge lamp lighting device is provided. A lighting fixture comprising: the discharge lamp lighting device according to any one of claims 1 to 5; and a fixture main body on which the discharge lamp lighting device is mounted.

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