JPH118083A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device which can control a chopper circuit and inverter circuit by associating them and can also make an individual control. SOLUTION: The output of a rectification circuit DB which rectifies an AC power source AC is converted into high-frequency power by a chopper circuit CH and an inverter circuit INV, so that discharge lamps La1 , La2 are lighted. The chopper circuit CH and the inverter circuit INV are controlled by a control circuit CN. The control circuit CN is provided with an oscillator 1 which generates a reference signal, a chopper control circuit 3 which generates a chopper control signal by synchronizing it with the reference signal to set the on-duty of the chopper control signal, an inverter control circuit 2 which generates an inverter control signal by synchronizing it with the reference signal to set the on-duty of the inverter control signal, and an operation indicating circuit 4 which makes an indication, associated with the output frequency of the oscillator 1, the on-duty of the chopper control signal, and the on-duty of the inverter control signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device mainly used for lighting equipment for houses.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, an inverter circuit I which performs DC-AC conversion and outputs high-frequency power is provided.
2. Description of the Related Art A discharge lamp lighting device for lighting a discharge lamp La at a high frequency by using NV is known. Inverter circuit I
For the NV, a switching element that is turned on and off at a high frequency is used. When the discharge lamp La is lit at a high frequency, the current limiting element such as an inductor can be reduced in size, so that the size can be reduced. In addition, a change in the voltage applied to the discharge lamp La (periodic change of the instantaneous value of the commercial power supply) Change) can be prevented.

The output voltage of the chopper circuit CH is used as the power supply of the inverter circuit INV. Chopper circuit CH
Uses a switching element that receives a pulsating voltage obtained by full-wave rectification of a commercial power supply, which is an AC power supply AC, by a rectifier circuit DB, and is turned on and off at a high frequency (frequency sufficiently higher than the commercial power supply frequency). Thus, the pulsating voltage is subjected to DC-DC conversion to output a DC voltage. That is, the chopper circuit CH generally includes an inductor connected in series to the switching element, and has a configuration in which energy stored in the inductor during the on-period of the switching element is released to the smoothing capacitor during the off-period of the switching element. . With such a configuration, the input current can flow at a high frequency.
The input current distortion from the AC power supply AC can be reduced only by providing a relatively small filter (small element constant) F for blocking high frequency between C and the rectifier circuit DB. For example, when the output voltage of the rectifier circuit DB is smoothed by a smoothing capacitor, the input current from the AC power supply AC flows only near the peak value of the voltage of the AC power supply AC. Since the switching is interrupted at about twice the frequency, a large filter is required to remove the input current distortion. However, by providing the chopper circuit CH, the size of the filter F can be significantly reduced. . In addition, the use of the chopper circuit CH allows the input current to flow in proportion to the input voltage, so that it is possible not only to suppress an increase in input current distortion but also to provide a high power factor discharge lamp lighting device. Will be possible.

[0004]

By the way, switching elements are used for the chopper circuit CH and the inverter circuit INV. In the above-described discharge lamp lighting device, the switching element of the chopper circuit CH and the inverter circuit INV are used.
By using the chopper control circuit CN ₁ and the inverter control circuit CN ₂ which operates independently from the switching element of the V being controlled. That is, the chopper control circuit CN
₁ controls the output voltage of the chopper circuit CH so as to be substantially constant, and controls the inverter circuit CN ₂
Performs control to keep the lamp current approximately constant, for example.

However, since those operating independently of the chopper control circuit CN ₁ and the inverter control circuit CN _2, preheating, starting, operation and in the normal such rated lighting, dimming lights, discharge lamps Emiless state at the end of life (half-wave lighting state due to exhaustion of filament electron-emitting material), no-load state with no discharge lamp connected, or when multiple discharge lamps are simultaneously lit by one inverter circuit Chopper circuit CH against abnormal operation such as load fluctuation when some discharge lamps come off.
And if an attempt controls the inverter circuit INV to the proper operating conditions, it will require complex configuration that gives each instruction to the chopper control circuit CN ₁ and the inverter control circuit CN _2.

On the other hand, there has been proposed a discharge lamp lighting device in which a switching element of an inverter circuit is also used as a switching element of a chopper circuit. In this configuration, if the inverter circuit is controlled, the chopper circuit is also controlled in conjunction with it, and there is no need to separately provide the chopper control circuit and the inverter control circuit. However,
Since it is impossible to control the chopper circuit and the inverter circuit individually, if an attempt is made to appropriately control the various operating states as described above, the relationship between the operation as the chopper circuit and the operation as the inverter circuit Therefore, complicated control in consideration of the above is required. That is, the configuration of the control circuit becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to control a chopper circuit and an inverter circuit by associating them with a relatively simple configuration and to control the chopper circuit in accordance with various operation states. It is an object of the present invention to provide a discharge lamp lighting device capable of individually controlling the inverter and the inverter circuit.

[0008]

According to a first aspect of the present invention, a rectifier circuit for rectifying an AC power supply and a chopper circuit for performing DC-DC conversion on the output of the rectifier circuit using a first switching element which is turned on and off at a high frequency. An inverter circuit that converts the output of the chopper circuit into high-frequency power using a second switching element that is turned on and off at a high frequency; and a high-frequency output of the inverter circuit including the resonance circuit and the discharge lamp is supplied to the discharge lamp via the resonance circuit. And a control circuit for controlling on / off of the first and second switching elements, wherein the control circuit generates a reference signal for setting an operating frequency of the first and second switching elements. And a chopper control signal for turning on and off the first switching element is generated in synchronization with the reference signal, and the on-duty of the chopper control signal is generated. A chopper control circuit for setting a second
An inverter control signal that generates an inverter control signal that turns on and off the switching element in synchronization with the reference signal and sets the on-duty of the inverter control signal; an output frequency of the oscillation circuit, an on-duty of the chopper control signal, and an on / off of the inverter control signal And an operation instruction circuit for instructing the duty in association with the duty. According to this configuration, the operating frequency of the chopper circuit and the inverter circuit is determined by the oscillation circuit, and the on-duty of the chopper control signal and the inverter control signal is determined by the chopper control circuit and the inverter control circuit, respectively. And an inverter circuit can be supplied with a chopper control signal and an inverter control signal that can independently set the on-duty, and the chopper circuit and the inverter circuit can be individually controlled.
In addition, since the operating frequencies of the chopper circuit and the inverter circuit are set by the oscillation circuit, it is possible to simplify the circuit configuration using a common circuit. Further, since the operation instruction circuit controls the oscillation circuit, the chopper control circuit, and the inverter control circuit in association with each other, the chopper circuit and the inverter circuit can be individually controlled, but the chopper circuit and the inverter circuit can be controlled according to various conditions. Can be controlled in association with the control, and relatively complicated control can be realized with a simple circuit configuration.

According to a second aspect of the present invention, in the first aspect of the present invention, the operation instruction circuit includes an oscillation circuit, an inverter control circuit, and a chopper control circuit according to each of preheating, starting, rated lighting, and dimming lighting. The frequency of the reference signal, the on-duty of the inverter control signal, and the on-duty of the chopper control signal are adapted to each state. According to this configuration, it is possible to appropriately control the chopper circuit and the inverter circuit according to various operating states during normal operation such as preheating, starting, rated lighting, and dimming lighting. If the voltage applied to the discharge lamp is changed from the preheating voltage to the starting voltage only by the relation between the operating frequency of the inverter circuit and the resonance frequency of the resonance circuit, The range of change in the operating frequency can be reduced, and control can be performed so that the operating frequency of the inverter circuit does not fall below the resonance frequency of the resonance circuit (a so-called advance phase region). As a result, the destruction of the second switching element due to the operation of the inverter circuit in the phase advance region can be prevented.

According to a third aspect of the present invention, in the first aspect of the present invention, the operation instruction circuit monitors an abnormality of the operation of the chopper circuit and the inverter circuit. The control circuit and the chopper control circuit are controlled in association with each other. According to this configuration, it is possible to appropriately control the chopper circuit and the inverter circuit so as to cope with various kinds of abnormalities, and it is possible to prevent, for example, destruction of circuit elements due to abnormally high output voltage of the chopper circuit. .

According to a fourth aspect of the present invention, in the first aspect, the operation instruction circuit monitors an output of the inverter circuit,
The chopper control circuit is controlled so that the on-duty of the chopper control signal is changed according to a change in the output of the inverter circuit. In this configuration, if the output of the inverter circuit decreases, the output of the chopper circuit is also reduced so that the inverter circuit and the chopper circuit are controlled in conjunction with each other. An abnormal increase in the output voltage can be prevented.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, a load circuit is provided with a plurality of discharge lamps connected in parallel, and the operation instruction circuit is configured such that at least one discharge lamp is not connected. Upon detection, the chopper control circuit is controlled so as to reduce the output of the chopper circuit. According to this configuration, in an apparatus for simultaneously lighting a plurality of discharge lamps with one inverter circuit, at least one
If the two discharge lamps are not connected, the power consumption of the inverter circuit will decrease. At this time, by lowering the output of the chopper circuit, an abnormal increase in the output voltage of the chopper circuit can be prevented.

According to a sixth aspect of the present invention, in the fourth aspect of the invention, the operation instruction circuit controls the chopper control circuit so as to stop the chopper circuit when the operation instruction circuit detects the end-of-life state of the discharge lamp or the no-load state of the inverter circuit. Is what you do. In general, operating the inverter circuit in the end-of-life state or in the no-load state puts a large stress on the inverter circuit, but in the end-of-life state or in the no-load state, the chopper circuit is stopped to prevent the inverter circuit from stressing. You can do it.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS This embodiment is shown in FIG.
And a plurality of (two in the figure) discharge lamps La₁, La _TwoOne
Lighting at high frequency using the inverter circuit INV
Therefore, the power supply of the inverter circuit INV is a commercial power supply.
A rectifier circuit such as a diode bridge for a certain AC power supply AC
Full-wave rectification by DB, DC-DC conversion by chopper circuit CH
It is gained by doing. Chopper circuit CH is input current
High frequency input current by chopping
Between the AC power supply AC and the rectifier circuit DB
By inserting a high-frequency blocking filter F,
The high-frequency current is prevented from leaking to the power supply AC. This
Filter F has a low frequency of about the power supply frequency of the AC power supply AC.
And a high frequency of about the operating frequency of the chopper circuit CH
Is designed to thwart. With this configuration, the input
Current distortion can be reduced, resulting in the IEEE standard
Regarding EMI of lighting equipment etc. defined as Class C
It is possible to achieve the standard. EMI
Standards have been set in Japan since 1988.
It is scheduled to be.

Chopper circuit CH and inverter circuit INV
Is controlled by a control circuit CN composed of an integrated circuit. The control circuit CN includes an oscillation circuit 1 for generating a reference signal.
And an inverter control circuit 2 that receives the reference signal and generates an inverter control signal that controls the on / off of the switching element of the inverter circuit INV; and a chopper control signal that receives the inverter control signal and controls the on / off of the switching element of the chopper circuit CH. And a chopper control circuit 3 that generates The oscillation circuit 1, the inverter control circuit 2, and the chopper control circuit 3 set the frequency, the duty ratio, and the idle period of the inverter control signal and the chopper control signal according to an instruction from the operation instruction circuit 4. Since the chopper control signal is generated upon receiving the inverter control signal, the frequency of the chopper control signal and the frequency of the inverter control signal are the same, and this frequency is set by the output frequency of the oscillation circuit 1.

As will be described later, a half-bridge type in which two switching elements are alternately turned on and off is employed as the inverter circuit INV, and an on-period of each switching element and a rest period during which both switching elements are off. (The period from when one switching element is turned on to when the other switching element is turned on) is set to one cycle of the reference signal output from the oscillation circuit 1. In response to the instruction from the operation instruction circuit 4, the inverter control circuit 2 sets the duty ratio of the inverter control signal (the ratio of the sum of the ON period and the idle period of each switching element) and the idle period. However, in the present embodiment, the inverter control signal is generated so as to turn on / off one of the switching elements without providing a pause period, and a signal whose on / off is inverted from the inverter control signal is generated to set the other switching element. Turn on and off.

The operation instruction circuit 4 gives instructions to the oscillation circuit 1, the inverter control circuit 2 and the chopper circuit 3 as described above, thereby controlling the chopper circuit CH and the inverter circuit INV to work together. Further, the frequency of the inverter control signal and the frequency of the chopper control signal are commonly set by the oscillation circuit 1, and the duty ratio between the inverter control signal and the chopper control signal is individually set by the inverter control circuit 2 and the chopper control circuit 3. Therefore, not only can the operation of the inverter circuit INV and the operation of the chopper circuit CH be controlled in association with each other, but also, if necessary, the inverter circuit INV and the chopper circuit CH can be individually controlled. Moreover, the circuit configuration is simplified by sharing the oscillation circuit 1 for generating the inverter control signal and the chopper control signal.

A more specific circuit example will be described.
The chopper circuit CH and the inverter circuit INV are as shown in FIG.
Is configured. The chopper circuit CH includes a rectifier circuit DB.
L between the output terminals of_ThreeAnd switching element Q_ThreeWhen
Connected in series with the switching element Q₁Between both ends of
Diode D_ThreeAnd smoothing capacitor C_ThreeConnect a series circuit with
It has a continuous configuration. This chopper circuit CH is a boost type
The operation is well known but will be briefly described. switch
Element Q_ThreeIs turned on and off at high frequency and the switching element
Child Q_ThreeDuring the ON period of the rectifier circuit DB and the inductor L_Three
A current to accumulate energy, and the switching element Q
_ThreeDuring the off period of the inductor L_ThreeEnergy stored in
Releases lugi. Here, the inductor L_ThreeAccumulated in
When releasing energy, the inductor L_ThreeOccur at both ends of
The voltage obtained by adding the voltage to the output voltage of the rectifier circuit DB is
Code D_ThreeThrough the smoothing capacitor C_ThreeIs applied to
From the smoothing capacitor C_ThreeVoltage across the rectifier circuit DB
The voltage will be higher than the input voltage. It is clear from this behavior
Like the switching element Q_ThreeWith the on / off of
Since a current flows through the rectifier circuit DB, the switching element Q
_ThreeIs turned on and off at high frequency,
Thus, the input current can flow at a high frequency.
In other words, the power supply frequency of the AC
Switching element Q _ThreeHigh frequency to turn on and off
By using a filter F of degree,
Thus, the input current distortion can be reduced.

The inverter circuit INV is a smoothing capacitor
C_ThreePair of switching elements connected between both ends of
Q₁, Q_TwoOne switching element
Q_TwoBetween both ends of the DC cut capacitor C₁₁, C
₁₂And inductor L_{twenty one}, L_{twenty two}And discharge lamp La₁, La_TwoWith
A series circuit is connected. Here, the capacitor C₁₁And Inn
Dacta L_{twenty one}And discharge lamp La₁Series circuit with a capacitor
C₁₂And inductor L_{twenty two}And discharge lamp La_TwoWhat is a series circuit with
Connected in parallel. In addition, the discharge lamp La₁, La_TwoIs a fluorescent light
And each discharge lamp La₁, La_TwoA pair of filaments
Between each inductor L_{twenty one}, L_{twenty two}With the resonance circuit
Constituent capacitor C_{twenty one}, C_{twenty two}Are respectively connected.
Further, the illustrated discharge lamp La₁, La_TwoHave different ratings
For example, a combination of 40W and 32W,
It becomes a combination of 40W and 30W. Thus the specification
Different discharge lamp La₁, La_TwoAre connected in parallel and one
To turn on the inverter circuit INV, an inductor
L_{twenty one}, L_{twenty two}And capacitor C _{twenty one}, C_{twenty two}Resonance times consisting of
Road is each discharge lamp La₁, La_TwoSet according to the specifications of
ing. However, the resonance frequencies of each resonance circuit are almost the same.
It is desirable to keep it.

Switching element Q _{3 of} chopper circuit CH
And the switching element Q ₁ of the inverter circuit INV,
MOSFET respectively used for the Q _2. Further, the switching element Q ₃ of the chopper circuit CH driving circuit 1
1, a chopper control signal is supplied to the switching elements Q ₁ and Q ₂ of the inverter circuit INV.
2, an inverter control signal is provided. The drive circuit 12 receives one inverter control signal and controls the two switching elements Q ₁ and Q ₂ to be turned on and off in opposite directions. Therefore, the on / off of the switching element Q ₂ is a logical value of the inverter control signal. the controls used as it is, turning on and off of the switching element Q ₁ is configured to control by inverting the logical value of the inverter control signal. Therefore, on-off of the switching element Q _1, a switching element Q ₂ becomes opposite to each other, varying the on-duty of the inverter control signals, the ratio of the switching element Q _1, Q ₂ of the on-period that is, the duty ratio described above Can be changed.

The chopper circuit CH in the smoothing capacitor C varying the on-duty of the switching element Q ₃
It is known that the voltage across ₃ changes. In the inverter circuit INV, the switching elements Q ₁ and Q ₂
When the operating frequency for turning on and off changes, the impedance of the resonance circuit changes, so that the voltage across the discharge lamps La ₁ and La ₂ changes. Further, when the duty ratio of the switching elements Q ₁ and Q ₂ of the inverter circuit INV is changed, the power supplied to the discharge lamps La ₁ and La ₂ changes, so that dimming lighting can be performed.

Incidentally, in order to monitor the operation state of the chopper circuit CH and the inverter circuit INV, the circuit of the present embodiment is provided with various detection functions. Chopper circuit C
The H, in order to monitor the voltage across the smoothing capacitor C _3, a capacitor C connected in parallel to the resistor R _31, R ₃₂ and resistor R ₃₂ for dividing the voltage across the smoothing capacitor C _3
32 are provided. In the control circuit CN, the capacitor C
_The switching element is input to the chopper control circuit 3 so that the voltage across the capacitor C ₃₂ (that is, the voltage across the smoothing capacitor C ₃ ) is maintained at the voltage value set in the chopper control circuit 3. to adjust the on-duty of the Q _3. Incidentally, the chopper control circuit 3 is for the basic configuration of the one-shot multivibrator, the capacitor C ₃₃ for determining the time constant is an integrated circuit controller C
External to N.

Further, in order to prevent the overcurrent from flowing through the switching element Q ₃ of the chopper circuit CH, resistor R ₃₃ for detecting the current passing through the switching element Q ₃ is connected in series with the switching element Q _3. 3, the control circuit CN comprises an overcurrent detection circuit 5 for comparing the voltage across the resistor R ₃₃ and a predetermined threshold. Overcurrent detection circuit 5
An instruction to turn off the switching element Q ₁ to Q ₃ to the inverter control circuit 2 and the chopper control circuit 3 when reaches the threshold voltage across the resistor R ₃₃ is increased. If the switching element Q ₃ is come off, because the smoothing capacitor C ₃ is only charged by the output of the rectifier circuit DB through inductor L _3, a smoothing capacitor C ₃
Of the AC power supply falls to about the peak voltage of the AC power supply AC. Further, since the operation of the inverter circuit INV is stopped, power is not supplied to the discharge lamps La ₁ and La ₂ .

On the other hand, in order to detect the operation state or connection state of the discharge lamps La ₁ and La ₂ , the inverter circuit INV
The output of the secondary winding of the respective discharge lamps La _1, inductor L ₂₁ is connected between the La _2, L ₂₂ is used. Each 2
The other end of the next winding is connected to one end of a different polarity, and the other end is connected to a path commonly connected via diodes D ₄₁ and D ₄₂ for rectification, and a diode D for rectification after common connection.
_The path through ₄₃ is divided into two. That is, according to the polarity of the current through the inductor L _21, L ₂₂ alternatively a current flows in one of the diodes D _41, D _42, a voltage is generated at all times to the cathode of the diode D _41, D ₄₂ is in the normal .
The voltage applied to the anode of the diode D ₄₃ is a voltage which cancel voltage across both secondary windings are in the normal state is set such that the voltage at the cathode of the diode D ₄₃ is not generated. The cathode voltages of the diodes D ₄₁ and D ₄₂ are smoothed by the resistor R ₄₁ and the capacitor C ₄₁ and input to the Emiless / no-load detection circuit 6 of the control circuit CN. The cathode voltage of the diode D ₄₃ is the resistance R ₄₃
And one lamp of the control circuit CN is smoothed by the capacitor C ₄₃ and inputted to the deviation detecting circuit 7.

Now, at the end of the life of the discharge lamps La ₁ and La ₂ , the electron emission material of one of the filaments scatters, making it difficult for electrons to be emitted. (Called the Emiless state in the sense of a phenomenon that occurs). At this time, the inductor L _21, L ₂₂ 2 winding output is decreased because no current flows only in half wave, resulting in the average value of the cathode potential of the diode D _41, D ₄₂ is reduced. The Emiless / no-load detecting circuit 6 detects such a voltage drop, and determines that the Emiless state. In addition, the filament may break or the discharge lamp La
Since _1, La ₂ inductor L ₂₁ in unloaded condition is not connected, the mean value of the output secondary winding of L ₂₂ is lowered,
The no-load state can be detected by the Emiless / no-load detection circuit 6. Here, in order to set a threshold value for the cathode potentials of the diodes D ₄₁ and D ₄₂ ,
Resistance R ₄₂ for impedance adjustment is connectable to the no-load detecting circuit 6.

On the other hand, when only one of the discharge lamps La ₁ and La ₂ is connected, the average value of the cathode potentials of the diodes D ₄₁ and D ₄₂ decreases and the secondary of the inductors L ₂₁ and L ₂₂ decreases. The difference between the winding outputs increases. As a result, since a relatively large voltage to the cathode of the diode D ₄₃ is generated, than it detects that one light out detection circuit 7 detects the rise of the voltage in in the one discharge lamp La _1, La ₂ is out .

The inductor L ₂₁ in Emiresu state, L ₂₂ is there is a risk that an excessive current flows do not function as a current limiting element to the switching element Q _1, Q ₂ of the inverter circuit INV, also at no load discharge lamp La ₁ , La ₂ , there is a possibility that the voltage across the smoothing capacitor C ₃ may rise abnormally due to excess energy. These phenomena are caused by the chopper circuit CH and the inverter circuit INV.
When the Emiless state or the no-load state is detected, the operation of the chopper circuit CH is stopped. This behavior, since the operation of the chopper circuit CH is the voltage across the aforementioned manner the smoothing capacitor C ₃ be stopped is reduced, the inverter circuit INV destruction is prevented. To further enhance safety, the inverter circuit INV may be stopped.

When the discharge lamps La ₁ and La ₂ are separated from each other by only one lamp, the load on the inverter circuit INV is reduced, so that the voltage across the smoothing capacitor C ₃ may increase due to a decrease in power consumption. Therefore, as in this case to prevent an increase in the voltage across the smoothing capacitor C _3, than if the on-duty of the switching element Q ₃ of the chopper circuit CH discharge lamp La _1, La ₂ is also connected to two lamps Also make it smaller.

Chopper circuit CH and inverter circuit INV
Output control is not performed only for abnormal conditions such as the above-mentioned Emiless state, no-load state, or one-light-off state. Even in the normal state, preheating, starting, rated lighting, dimming lighting, etc. It is necessary to carry out according to each state. That is, at the time of preheating, the discharge lamps La ₁ , La ₂
Switching element of the chopper circuit CH for the operating frequency of the inverter circuit INV is set higher, also to avoid the abnormal increase in the voltage across the smoothing capacitor C ₃ because less power consumption to a voltage to be applied is set to be lower across the Q
_It is necessary to reduce the on-duty of ₃ . here,
The operating frequency of the inverter circuit INV is set in a region higher than the resonance frequency of the resonance circuit (resonance frequency at no load) (called a slow phase region).

Further, at the time of starting, the voltage applied between both ends of the discharge lamps La ₁ and La ₂ must be increased to the starting voltage, so that the operating frequency of the inverter circuit INV needs to be set lower than at the time of preheating. However, since the setting range of the operating frequency of the inverter circuit INV must be in the lag region, in order to obtain a relatively high starting voltage,
Increasing the on-duty of the switching element Q ₃ to increase the output voltage of the chopper circuit CH.

At the time of rated lighting, the output voltage of the chopper circuit CH is reduced from that at the time of starting so that the discharge lamps La ₁ and La ₂ can maintain a stable lighting state, and the inverter circuit INV is operated so that the rated output can be obtained. Is set appropriately. Further, for dimming lighting, the operating frequency of the inverter circuit INV is set to a higher frequency than that at the time of rated lighting (for example, it is set to 50 kHz at the time of rated lighting, and is set to 80 kHz at the time of dimming lighting), and the discharge lamp The voltage applied to La ₁ , La ₂ is reduced, or the duty ratio of switching elements Q ₁ , Q ₂ is changed (for example, it is set to 1: 1 at the time of rated lighting, and set to 2: 1 at the time of dimming lighting). ), The power supplied to the discharge lamps La ₁ and La ₂ is reduced. At this time, the chopper circuit CH
Since load is reduced, in order to prevent abnormal rise of the voltage across the smoothing capacitor C _3, the switching element Q ₃
On duty is smaller than at the time of rated lighting.

[0032] Incidentally, when the power-on chopper CH before the inverter circuit INV is operated to start the operation, the voltage across the smoothing capacitor C ₃ to the load is light chopper circuit CH is there is a possibility that abnormal increase, also Also when turning off the discharge lamps La ₁ and La ₂ , if the inverter circuit INV stops prior to the chopper circuit CH, there is a possibility that the voltage across the smoothing capacitor C ₃ abnormally increases. Therefore, when the power is turned on, the inverter circuit INV operates simultaneously with the operation of the chopper circuit CH or the chopper circuit CH.
Must be controlled to operate before the operation of
When the light is turned off, the inverter circuit INV is connected to the chopper circuit C.
It is necessary to stop after the operation of H. The same applies to dimming, and the output of the chopper circuit CH needs to be reduced before the output of the inverter circuit INV decreases.

As described above, the normal and abnormal conditions
Accordingly, the chopper circuit CH and the inverter circuit INV
Operating frequency, on-duty, or operating timing
Must be controlled. Therefore, various timing
And a timer circuit 8 for controlling
Timing and Emiless / no load detection circuit 6 or 1
Based on the abnormal state detected by the lamp deviation detection circuit 7,
Determine the operation of the chopper circuit CH and the inverter circuit INV
A mode switching circuit 9 is provided in the control circuit CN. Mo
The mode switching circuit 9 includes an output frequency of the oscillation circuit 1 and an inverter.
Of output signals from control circuit 2 and chopper control circuit 3
Control the combination of on-duty. Here,
The barter control circuit 2 has a one-way
The basic configuration of the multivibrator is
Capacitor C that determines the time constant ₃₄Is attached externally.
Also, a capacitor C that determines the time constant of the oscillation circuit 1₃₁Also
Externally attached.

The timer circuit 8 has a function of limiting the preheating period and the starting period after the power is turned on. The timer circuit 8 supplies signals (Tyo, Tsid) corresponding to the preheating period and the starting period to the mode switching circuit 9, respectively. The switching circuit 9 controls the oscillation circuit 1, the inverter control circuit 2, and the chopper control circuit 3 in conjunction with each other according to the preheating period, the starting period, and the lighting period. The power-on timing is given by a reset release signal input from the internal power reset circuit 22 to the timer circuit 8 upon receiving the output of the constant voltage / constant current circuit 21. The constant voltage / constant current circuit 21 is a circuit for generating various reference voltages and reference currents used in the control circuit CN, and resistors R _{38 to} R ₄₀ for setting them can be externally provided. Also,
Preheating period is set by a resistor R ₃₅ and capacitor C ₃₅ which is external, the starting period is set by a resistor R ₃₆ and capacitor C _36. Further, the signal timer circuit 8 to set a timing, such as during off during the extinguishing time and dimming or during Emiresu state described above (respectively Tstop, Tdim, Temi) also outputs, timing when dimming the capacitor C ₃₇ resistance R
₃₇ . Here, the light is turned off by the power reset circuit 2 monitoring the output voltage of the constant voltage / constant current circuit 21.
2 detected. A signal for switching to the dimming state is externally supplied to the timer circuit 8, and an instruction is supplied to the mode switching circuit 9 through the timer circuit 8.

The mode switching circuit 9 also receives detection signals from the Emiless / no-load detecting circuit 6 and the one-light out-of-light detecting circuit 7, and outputs the oscillation circuit 1 and the inverter in accordance with the Emiless state or no-load state or the one-light out-of-light state. The outputs of the control circuit 2 and the chopper control circuit 3 are controlled in conjunction with each other. As is clear from the above description, the operation instruction circuit 4 shown in FIG.
Is composed of an overcurrent detection circuit 5, an Emiless / no-load detection circuit 6, an off-light detection circuit 7, a timer circuit 8, and a mode switching circuit 9 in the configuration shown in FIG.

As described above, the mode switching circuit 9 can control the oscillation circuit 1, the inverter control circuit 2, and the chopper control circuit 3 in conjunction with each other so as to perform an operation suitable for normal or abnormal conditions. is there. That is, as compared with the conventional case where the chopper circuit CH and the inverter circuit INV are independently controlled, the chopper circuit C
H and the inverter circuit INV can be operated under appropriate conditions. Moreover, the inverter control circuit 2 and the chopper control circuit 3 share the oscillation circuit 1, and the mode switching circuit 9 sets the output frequency of the oscillation circuit 1 and the on-duty of the inverter control signal and the chopper control signal. Therefore, it is possible to independently control the chopper circuit CH and the inverter circuit INV with a relatively simple circuit configuration. As described above, the control circuit CN is an integrated circuit, and the circuit configuration is simplified by sharing a part of the circuit as described above, so that the integration is easy and the cost can be reduced. . In addition, since the frequency of the inverter control signal and the chopper control signal is determined by the oscillation circuit 1 and the on-duty is set by the inverter control circuit 2 and the chopper control circuit 3, the control of the inverter control signal and the chopper control signal is easy. Further, the chopper circuit CH and the inverter circuit IN
Since V control and abnormality detection are performed by one integrated circuit, the mounting area of the circuit is reduced. Control circuit C
The manufacturing cost can be reduced by using a bipolar process for the N manufacturing process. In the control circuit CN of FIG. 2, the numbers with circles correspond to the numbers in the terminals in FIG.

[0037]

According to the first aspect of the present invention, there is provided a rectifier circuit for rectifying an AC power supply, a chopper circuit for performing DC-DC conversion on a rectifier circuit output using a first switching element which is turned on and off at a high frequency, An inverter circuit for converting the output of the chopper circuit into high-frequency power using a second switching element that is turned on and off, and a load circuit including a resonance circuit and a discharge lamp, wherein the high-frequency output of the inverter circuit is supplied to the discharge lamp via the resonance circuit And a control circuit for controlling on / off of the first and second switching elements, the control circuit comprising: an oscillation circuit for generating a reference signal for setting operating frequencies of the first and second switching elements; A chopper control signal for turning on and off the switching elements of the control circuit is generated in synchronization with the reference signal, and the on-duty of the chopper control signal is set. A control circuit, an inverter control signal for generating an inverter control signal for turning on and off the second switching element in synchronization with the reference signal, and setting the on-duty of the inverter control signal; an output frequency of the oscillation circuit and the turning on of the chopper control signal. An operation instruction circuit for instructing the duty and the on-duty of the inverter control signal in association with each other.The operating frequency of the chopper circuit and the inverter circuit is determined by the oscillation circuit, and the operation frequency is determined by the chopper control circuit and the inverter control circuit. Since the on-duty of the chopper control signal and the inverter control signal is determined, the chopper control signal and the inverter control signal that can set the on-duty independently of each other can be given to the chopper circuit and the inverter circuit. Circuits and inverters There is an advantage that it is possible to control the road separately. In addition, since the operating frequencies of the chopper circuit and the inverter circuit are set by the oscillation circuit, there is an advantage that the circuit configuration can be simplified using a common circuit. Further, since the operation instruction circuit controls the oscillation circuit, the chopper control circuit, and the inverter control circuit in association with each other, the chopper circuit and the inverter circuit can be individually controlled, but the chopper circuit and the inverter circuit can be controlled according to various conditions. And control can be performed in association with each other, so that relatively complicated control can be realized with a simple circuit configuration. According to the second aspect of the present invention, the operation instruction circuit is configured to perform preheating, starting,
The oscillator circuit, the inverter control circuit, and the chopper control circuit are controlled in association with each other in accordance with each state of the rated lighting and the dimming lighting, and the frequency of the reference signal, the on-duty of the inverter control signal, and the on-duty of the chopper control signal are respectively controlled. The chopper circuit and the inverter circuit can be appropriately controlled according to various operating states during normal operation such as preheating, starting, rated lighting, and dimming lighting. If the voltage is set higher than the rated lighting time, compared to the case where the voltage applied to the discharge lamp is changed from the preheating voltage to the starting voltage only by the relationship between the operating frequency of the inverter circuit and the resonance frequency of the resonance circuit, the inverter circuit The range of change of the operating frequency of the inverter circuit can be reduced, and the operating frequency of the inverter circuit is It is possible to control so as to prevent from becoming lower (become a so-called phase advancing area). As a result, there is an advantage that the destruction of the second switching element due to the operation of the inverter circuit in the phase advance region can be prevented.

According to a third aspect of the present invention, the operation instructing circuit monitors an abnormality in the operation of the chopper circuit and the inverter circuit, and when an abnormality is detected, the oscillation circuit, the inverter control circuit, and the chopper control in response to the abnormality. In the case of controlling by associating with a circuit, the chopper circuit and the inverter circuit can be appropriately controlled so as to cope with various kinds of abnormalities, for example, preventing destruction of circuit elements due to abnormally high output voltage of the chopper circuit. There is an advantage that can be.

The operation instruction circuit monitors the output of the inverter circuit and controls the chopper control circuit so as to change the on-duty of the chopper control signal according to the change of the output of the inverter circuit. In such a case, if the output of the inverter circuit decreases, the inverter circuit and the chopper circuit are linked and controlled so that the output of the chopper circuit also decreases. There is an advantage that an abnormal rise of the output voltage can be prevented.

According to a fifth aspect of the present invention, a load circuit includes a plurality of discharge lamps connected in parallel.
When detecting that at least one discharge lamp is not connected, the chopper control circuit is controlled so as to reduce the output of the chopper circuit. In a device in which a plurality of discharge lamps are simultaneously turned on by one inverter circuit, Unless at least one discharge lamp is not connected, the power consumption of the inverter circuit is reduced. Therefore, by lowering the output of the chopper circuit at this time, it is possible to prevent an abnormal increase in the output voltage of the chopper circuit. There is.

According to a sixth aspect of the present invention, the operation instruction circuit controls the chopper control circuit so as to stop the chopper circuit when the end-of-life state of the discharge lamp or the no-load state of the inverter circuit is detected. Adopting a configuration in which the chopper circuit is stopped in a terminal state or a no-load state has an advantage that stress on the inverter circuit can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a specific circuit diagram of the above.

FIG. 3 is a block diagram of a control circuit used in the embodiment.

FIG. 4 is a block diagram showing a conventional example.

[Explanation of symbols]

1 oscillator 2 inverter control circuit 3 chopper control circuit 4 operation instruction circuit 5 overcurrent detection circuit 6 Emiresu / no-load detecting circuit 7 one light out detection circuit 8 timer circuit 9 mode switching circuit AC AC power supply C _11, C ₁₂ capacitor C _21, C ₂₂ capacitor CH chopper circuit CN control circuit DB rectifying circuit INV inverter circuit L _21, L ₂₂ inductor La _1, La ₂ discharge lamp Q ₁ to Q ₃ switching elements

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroshi Seike 1048 Kadoma Kadoma, Osaka Pref.Matsushita Electric Works, Ltd.

Claims (6)

[Claims] 1. A rectifier circuit for rectifying an AC power supply, a chopper circuit for performing DC-DC conversion on a rectifier circuit output using a first switching element turned on / off at a high frequency, and a second switching turned on / off at a high frequency An inverter circuit for converting the output of the chopper circuit into high-frequency power using the element; a load circuit including a resonance circuit and a discharge lamp, wherein the high-frequency output of the inverter circuit is supplied to the discharge lamp via the resonance circuit; A control circuit for controlling the on / off of the switching element, the control circuit comprising: an oscillation circuit for generating a reference signal for setting an operating frequency of the first and second switching elements; and a chopper for turning on and off the first switching element A chopper control circuit that generates a control signal in synchronization with the reference signal and sets the on-duty of the chopper control signal; An inverter control signal that generates an inverter control signal that turns on and off the switching element in synchronization with the reference signal and sets the on-duty of the inverter control signal; an output frequency of the oscillation circuit, an on-duty of the chopper control signal, and an on / off of the inverter control signal An operation instruction circuit for instructing the discharge lamp in association with a duty. 2. An operation instruction circuit controls an oscillation circuit, an inverter control circuit, and a chopper control circuit in association with each state of preheating, starting, rated lighting, and dimming lighting, and controls a reference signal frequency and an inverter control. 2. The discharge lamp lighting device according to claim 1, wherein the on-duty of the signal and the on-duty of the chopper control signal are adapted to each state. 3. An operation instruction circuit monitors an abnormality in the operation of the chopper circuit and the inverter circuit, and when the abnormality is detected, controls the oscillation circuit, the inverter control circuit, and the chopper control circuit in association with the abnormality. The discharge lamp lighting device according to claim 1, wherein: 4. The operation instruction circuit monitors an output of the inverter circuit, and controls the chopper control circuit so as to change an on-duty of the chopper control signal in accordance with a change in the output of the inverter circuit. Item 10. The discharge lamp lighting device according to Item 1. 5. The load circuit includes a plurality of discharge lamps connected in parallel, and the operation instruction circuit reduces an output of the chopper circuit when detecting that at least one discharge lamp is not connected. The discharge lamp lighting device according to claim 4, wherein the chopper control circuit is controlled. 6. The control circuit according to claim 4, wherein the operation instruction circuit controls the chopper control circuit so as to stop the chopper circuit when detecting an end-of-life state of the discharge lamp or a no-load state of the inverter circuit. Lighting device.