JPH10164851A - Power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply for enhancing the crest factor of load current. SOLUTION: A rectifier circuit DB full-wave rectifies an AC power supply inputted through an input filter F1 . A control circuit 2 delivers a drive signal to the switching elements Q1 , Q2 in an inverter circuit 1 and turns each switching element Q1 , Q2 on/off. In the control circuit 2, a detection circuit 3 divides the output voltage from the rectifier circuit DB and delivers the divided voltage to a limiter 4. The limiter 4 outputs a voltage V2 produced by shaping the detection voltage from the detection circuit 3 using upper and lower limit values V4 , V3 . A driving voltage control section 5 determines the driving frequency of the inverter circuit 1 depending on a voltage V2 . Since the maximum and minimum driving frequencies are determined, respectively, by the upper and lower limit values V4 , V3 of the limiter 4, the control circuit 2 controls the driving frequency of the switching element Q1 , Q2 between the maximum and minimum frequencies depending on the rectified voltage from the rectifier circuit DB.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for converting a DC power supply obtained by rectifying and smoothing an AC power supply into a high-frequency power supply.

[0002]

2. Description of the Related Art Conventionally, an AC power supply is rectified by a rectifier and its output is smoothed by a smoothing capacitor to obtain a DC power supply. The DC power supply is converted into a high-frequency voltage by an inverter and supplied to a discharge lamp. There is known a so-called capacitor input type power supply device. However, in this type of power supply device, there is a problem that the pause period of the input current flowing from the AC power supply is lengthened, the power factor is reduced, and the harmonic distortion of the input current is increased. For this reason,
Some have proposed to insert a large inductor between the output terminal of the rectifier and the smoothing capacitor, or insert a chopper circuit in the input stage to suppress input harmonic distortion.
There is a problem that the size of the apparatus itself increases and the cost increases.

In order to solve this kind of problem, a power supply device as shown in FIG. 52 has been proposed (see Japanese Patent Application Laid-Open No. Hei 4-190673). In this power supply apparatus, the vibration element of the inverter circuit 1 connected to the smoothing capacitor circuit C ₁ (e.g., LC resonance circuit) of Z ₂ one end, the rectifier output high potential side output end and the power supply return the DB Connected via the impedance element Z ₁ , the rectifier DB from the AC power supply AC → the impedance element Z ₁ → the vibration element Z _{2 of the} inverter circuit 1 → the switching element Q _{19 of the} inverter circuit 1
It has established a current path in response to the potential V _c of the connection point between the impedance elements Z ₁ and the vibrating element Z _2, charging of the withdraw-in and smoothing capacitor C ₁ of the input current to the impedance element Z ₁ side is done It is. That is, the potential of the high potential side output end and the diode D ₁ of the connection point of the rectifier DB V _b
When, when the V _c is lower than V _b V _b and V _c
Voltage difference between the is applied to the impedance element Z _1, charge to the impedance element Z ₁ are accumulated. On the other hand, V _c
Becomes larger than _Vb , the impedance element Z
Charges accumulated in the ₁ is charged through the diode D ₁ to the smoothing capacitor C _1. Such an operation is performed by the AC power source A.
Since the current is repeated over the entire period of the commercial cycle of C, the input current always flows, and as a result, the input power factor is increased and the harmonic distortion of the input current is improved.
Thus, power supply device shown in FIG. 52, by providing the impedance element Z _1, is necessary or putting chopper circuit in the input stage to insert a large inductor between the output terminal and the smoothing capacitor C ₁ of the rectifier DB This eliminates input harmonic distortion without increasing the size of the device.

FIG. 54 shows a specific circuit example of this power supply device. This power supply includes an AC power supply AC, an input filter F
Rectifier D for rectifying an AC power supply AC that is input via the ₂
And B, a rectifier smoothing capacitor C ₁ connected through the diode D ₁ between the output terminals of the DB, a smoothing capacitor C
₁ like a fluorescent lamp having a series circuit of switching elements Q ₁ and Q ₂ connected between both ends of the switching element Q ₁ , an inductor L ₁ connected between both ends of the switching element Q ₂ , a capacitor C ₃ for DC cutoff, and a filament. a series circuit comprising a lamp La such, lamp and a capacitor C ₂ connected between the non-power side end of both filaments La, rectifier DB and the connection point of the diodes D ₁ and a capacitor C ₃ and the lamp La
The composed connected capacitors C ₁₂ Metropolitan between the connection point. In this power supply device, an LC series resonance circuit including a capacitor C ₂ and an inductor L ₂ operates as a vibration element Z ₂ of the inverter circuit 1, and the switching element Q 2
_By alternately turning on and off ₁ and Q ₂ at high speed,
The high frequency power is supplied to the lamp La.

[0005] In this power supply apparatus, the capacitor C ₁₂ as an impedance element, the rectifier DB and the diode D
₁ is connected to the connection point of the DC cut capacitor C ₃ and the lamp La, so that the capacitor C ₃
And the input current drawn by V _OUT (voltage amplitude of high-frequency voltage) potential at the connection point of the lamp La, or the charging of the smoothing capacitor C ₁ is performed. That is, the potential V
When _OUT drops below the absolute value of the supply voltage V _IN of the AC power source AC, the voltage of the difference in absolute value and the voltage V _OUT of the voltage V _IN is applied to the capacitor C _12, charge is accumulated in the capacitor C _12. On the other hand, when the potential V _OUT rises, the capacitor C ₁₂
Accumulated charge to charge the capacitor C ₁ through the diode D ₁ to. Since this operation is performed in all sections of the AC power supply AC, harmonic distortion of the input current is improved. Thus, the high-frequency charging method can reduce the number of components and suppress input harmonic distortion.

However, in the power supply device described above, a ripple component synchronized with the pulsating waveform generated in the input current is generated in the load current waveform by the following operation. Charging of the capacitor C ₁₂ provided in the power unit is carried out in path of the diode bridge DB → capacitor C ₁₂ → the capacitor C ₃ → inductor L ₁ → switching element Q _2, the capacitor C ₁₂ is indicated by arrows in FIG. 53 Charged in the direction. A discharge of the capacitor C ₁₂ is mainly capacitor C ₁₂ → the diode D ₃ → the switching element Q ₁ → inductor L ₁
→ place in path of the capacitor C _3, the voltage across the capacitor C ₁ at this time is lowered.

[0007] Here, the charge timing of the discharge of the ON switching element Q _1, Q ₂ of the capacitor C _12, but is not started off at the same time, the voltage across V _C4 of the capacitor C _12, the power supply voltage V _IN , the voltage across V _L1 of inductor L _1, is determined by the voltage relationship between the voltage across V _C3 of the capacitor C _3. Now, in the case where the capacitor C ₁₂ is not charged and discharged, the circuit of Figure 53 may be considered to be configured as shown in FIG. 54. Further, it may be considered that when the capacitor C ₁₂ is charged and discharged has a configuration in Figure 55.
That is, the ripple occurs due to the output difference due to the switching between the circuits of FIGS. 54 and 55.

In this case, if the outputs of the circuits of FIGS. 54 and 55 become substantially the same, the ripple component can be reduced. By the way, when considering the circuits shown in FIGS. 54 and 55, the different points are in the configuration of the vibration system. That is,
The first vibration system in the inductor L ₁ and capacitor C ₂ is formed in the case of FIG. 54, in the case of FIG. 55 is an inductor L
The second vibration system ₁ and the near point and the support C _2, C ₁₂ is constituted. Therefore, if the output of this vibration system becomes almost the same,
The ripple component becomes smaller.

Here, if the output characteristics of the respective vibration systems are as shown in FIG. 56, for example, the oscillation frequency of the inverter circuit 1 (hereinafter, this frequency is referred to as f ₀ ) and the output value of each It can be seen that the frequency should be set to be constant. 56A shows the output characteristics of the first vibration system, and B shows the output characteristics of the second vibration system. FIG.
There is also a power supply device as shown in FIG. In this power supply, the AC power source AC via the input filter F ₂ consisting of a transformer and a capacitor between the input terminals of the full-wave rectifier DB is connected. Full-wave rectifier smoothing capacitor C ₁ through the diode D ₁ is between the output terminal of the DB are connected. A series circuit of switching elements Q ₁ and Q ₂ is connected between both ends of the smoothing capacitor C ₁ . Each switching element Q _1, Q _2, respectively diode D _11, D ₁₂ are connected in inverse-parallel. Diode D ₁ and the full-wave rectifier DB
The connection point, one end of the capacitor C ₃ is connected, one end of the inductor L ₁ is connected to a connection point of the switching elements Q _1, Q _2. Between other ends of the inductor L ₁ of the capacitor C _3, is connected to the power source side terminals of both filaments of the lamp La, the inter-non-power side terminals of both filaments of the lamp La is connected to the capacitor C ₂ I have. The capacitor C is across diode D _3
11 are connected in parallel. The control circuit 2 controls the on / off of the switching elements Q ₁ and Q ₂ .

The operation of the power supply will be described. First, the operation of the inverter circuit 1 will be described. In the inverter circuit 1, when the switching element Q _1, Q ₂ are turned on and off alternately at a high speed, and converts the DC voltage of the smoothing capacitor C ₁ to a high frequency, the lamp La is a high-frequency lighting. Capacitor C ₂ constitutes a preheating current path of the filament of the lamp La, also serves as the resonant capacitor of the inductor L _1. Capacitor C ₃ is a coupling capacitor for DC component cut.

In the above circuit, the switching element Q ₂
There is turned on, the capacitor C ₁ from the capacitor C ₁ via the capacitor C ₁₁ → the capacitor C ₃ → lamp La and the capacitor C ₂ → inductor Ll → switching element Q ₂
Current flows on the path returning to. At this time, the voltage appearing at each element has a relationship of V _C1 ≒ V _C11 + V _C3 + V _C2 + V _L1 .
A capacitor C ₃ is provided between the output terminals of the full-wave rectifier DB.
A parallel circuit of the lamp La and the capacitor C _2, since the inductor L ₁ is _{connected, | V IN |> V C3} + V C2
When the relationship of + V _L1 ≒ V _C1 −V _C11 is satisfied, the capacitor C ₃ → the lamp La and the capacitor C are output from the full-wave rectifier DB.
Parallel circuit of ₂ → inductor L ₁ → switching element Q ₂
, A current flows in a path returning to the full-wave rectifier DB. That results in the capacitor C ₁₁ which is inserted between the output terminal and the capacitor C ₁ of the full-wave rectifier DB to bear the voltage difference between the full wave rectifier rectifying the output voltage V _C1 of the capacitor C ₁ of the DB, the input Voltage | V _IN | is the capacitor C ₁
Be lower than the voltage V _C1, the input current I _IN flows, the input power factor becomes higher. The input current waveform removing high frequency components by the input filter F ₂ consisting of a capacitor and the transformer can be a waveform close to a small sine wave of harmonic components.

[0012] In the above-described power supply, by utilizing the high frequency operation of the inverter circuit 1 according to the on-off switching element Q _1, Q _2, to charge the capacitor C _11, have improved distortion of the input current. Therefore, in order to make the input current substantially sinusoidal, since the voltage V _C1 of the smoothing capacitor C ₁ is almost constant, the voltage borne by the capacitor C ₁₁ changes according to the pulsating flow of the input voltage. Become.

In this case, the resonance state of the inverter circuit 1 also changes, and as a result, the current flowing through the load changes according to the pulsating component included in the input voltage. FIG. 58 (a) (b)
As shown in FIG.
And the absolute value | V _IN | of the power supply voltage V _IN , the crest factor (crest value) of the load current is deteriorated, which causes a problem such as flickering of the lamp. Therefore, in this power supply device, a detection point indicating a similar shape or a substantially anti-similar shape to the ripple component of the load current is provided in the main circuit, the unevenness of the load current is detected from the detection signal, and the operating frequency of the convex portion is The control circuit 2 switches and controls the operating frequency so as to be higher than the operating frequency of the concave portion, thereby suppressing the ripple of the load current.

In the same power supply device, the output voltage of the full-wave rectifier DB is detected, and the high-frequency current is controlled in accordance with the absolute value of a difference from a predetermined value, so that the load current ripple is reduced. Can be suppressed.

[0015]

Among the power supply devices described above, the power supply devices shown in FIGS. 52 to 56 perform dimming control or the like to change the output of a lamp La as a load, or to change the power supply voltage. Alternatively, when correcting a change in the lamp output of the lamp La due to a change in ambient temperature or the like, it is necessary to control the load output by changing the operating frequency of the power supply device. For example, when performing dimming control of the lamp La is to increase the operating frequency, the inductor L ₁ and capacitor C
There is a method of reducing the power supplied to the lamp La by shifting the resonance frequency from the resonance frequency of the first vibration system composed of the _two .

However, in the circuit diagram of FIG.
The oscillation frequency of the inverter circuit 1 is simply changed to the resonance frequency f ₀
, The ripple component of the operating current increases, the crest factor of the load current deteriorates, and the flicker of the lamp La may occur. Therefore, a method is considered in which the oscillation frequency of the inverter circuit 1 is shifted and, at the same time, the impedance of the vibration system is changed accordingly so that the outputs of the vibration systems in FIGS. 54 and 55 become substantially the same. in order to change the output of the system must such use resonance system having a frequency characteristic in place of the capacitor C ₁₂ in FIG. 53, the circuit cost becomes complicated is raised.

In the power supply device shown in FIGS. 57 and 58, the operating frequency of the power supply device is switched so that the unevenness of the load current is detected and the operating frequency of the convex portion becomes higher than the operating frequency of the concave portion. Alternatively, by simply detecting the output voltage of the rectifier DB and controlling the high-frequency current in accordance with the absolute value of a difference from a predetermined value, the crest factor of the load current is substantially constant with respect to power supply voltage fluctuation. However, there is a problem that the load current cannot be kept constant while maintaining the load current.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a power supply device in which a ripple of a load current is suppressed and a crest factor is improved. It is in.

[0019]

According to the present invention, in order to achieve the above object, a rectifier circuit for full-wave rectifying an AC power supply, a smoothing capacitor for smoothing an output of the rectifier circuit,
An inverter circuit that includes a switching element for switching the output of the smoothing capacitor, converts the output of the smoothing capacitor into a high frequency, and supplies the high frequency to the load; a detection unit that detects the output of the rectifier circuit; And a control circuit for supplying a drive signal to the switching element, the absolute value of the high-frequency current supplied to the load decreases near the peak value of the power supply voltage of the AC power supply. In the vicinity of the zero crossing of the power supply voltage of the power supply, the load current has low-frequency ripple such that the absolute value of the high-frequency current supplied to the load increases, and the control circuit converts the output of the limiter unit into a frequency to drive the switching element. Signal, and reduce the frequency of the drive signal to the upper and lower limits to reduce the low frequency ripple that occurs in the load current. Control is performed between the corresponding minimum frequency and maximum frequency. In the invention according to claim 2, the output of the inverter circuit is reduced by increasing the absolute value of the difference between the upper limit value and the lower limit value. Depending on the voltage waveform of the power supply,
The driving frequency of the switching element can be controlled.

According to a third aspect of the present invention, when the effective value of the power supply voltage of the AC power supply increases, the absolute value of the difference between the upper limit value and the lower limit value increases, and the power supply voltage of the AC power supply increases. When the effective value decreases, the absolute value of the difference between the upper limit value and the lower limit value decreases. In the invention according to claim 4, when the effective value of the power supply voltage of the AC power supply increases, the frequency of the drive signal is clamped at the maximum frequency. When the effective value of the power supply voltage of the AC power supply is reduced, the period during which the frequency of the drive signal is clamped at the minimum frequency is increased, so that even if the power supply voltage of the AC power supply fluctuates, the inverter The output of the circuit can be kept substantially constant.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, the control circuit operates according to an output of the limiter unit.
The on-duty of the drive signal is controlled between a maximum on-duty and a minimum on-duty which are respectively determined by an upper limit value and a lower limit value of the limiter unit. In accordance with the output, while controlling the frequency of the drive signal between the minimum frequency and the maximum frequency corresponding to the upper limit and the lower limit, respectively, the maximum on-duty and the minimum on-duty determined by the upper and lower limits, respectively. Since the on-duty of the drive signal is controlled during the period, it is possible to control the on-duty of the drive signal of the inverter circuit according to the voltage waveform of the AC power supply.

According to a seventh aspect of the present invention, in any of the first to sixth aspects, the on-duty of the drive signal of the switching element is clamped to the maximum on-duty for a certain period. The on-duty of the signal is clamped to the minimum on-duty for a certain period of time. Is controlled to control the absolute value of the difference between the maximum on-duty and the minimum on-duty of the drive signal, so that the inverter according to the voltage waveform of the AC power supply The on-duty of the drive signal of the circuit can be controlled.

According to a tenth aspect of the present invention, in the first to ninth aspects of the present invention, the output of the limiter unit is clamped to the upper limit value in a range where the detection value of the detection unit exceeds the upper limit value, and the detection value of the detection unit is reduced. In the range below the lower limit, the limiter unit outputs a voltage proportional to the waveform of the detected value, so that the driving frequency of the switching element can be controlled according to the voltage waveform of the AC power supply.

According to an eleventh aspect of the present invention, in the first to ninth aspects, the voltage across the smoothing capacitor is detected, and when the voltage across the smoothing capacitor is low, the control circuit increases the output of the inverter circuit. Even when the power supply voltage of the input power supply fluctuates, the output of the inverter circuit can be kept substantially constant. According to a twelfth aspect, in the first to ninth aspects, the load current flowing through the load is detected, and the upper limit value and the lower limit value of the limiter are adjusted so as to reduce low frequency ripple included in the load current. And
The crest factor of the load current can be improved.

According to a thirteenth aspect, in the first to ninth aspects, the minimum frequency is set to a value higher than the resonance frequency of the inverter circuit, so that the loss of the switching element can be reduced. According to a fourteenth aspect of the present invention, in the first to ninth aspects, the on-duty of the drive signal is adjusted so as to correct the variation of components, and the load output, the input current distortion, and the crest factor of the load current are improved. Since the frequency of the drive signal is controlled in advance, variations in output due to variations in components can be corrected.

According to a fifteenth aspect of the present invention, in the first to ninth aspects, a load current detecting circuit for detecting a load current, and when the detected value of the load current detecting circuit exceeds a predetermined reference value, the switching element is driven. Since the thinning control circuit for thinning out the signal and intermittently driving the switching element is provided, the crest factor of the load current can be improved as in the twelfth aspect.

According to a sixteenth aspect of the present invention, in the first to ninth aspects of the present invention, the output of the limiter is a binary value consisting of only an upper limit value and a lower limit value. The drive frequency of the switching element can be controlled according to the waveform. According to the seventeenth aspect, in the first to ninth aspects, the control circuit controls the output of the inverter circuit by detecting the current flowing to the load at the peak of the output of the rectifier circuit. By suppressing the fluctuation, the crest factor can be improved.

According to the eighteenth aspect of the present invention, in the first to ninth aspects, the control circuit drives the switching element using a preset drive signal in synchronization with the voltage waveform of the AC power supply. Depending on the voltage waveform with a simple configuration,
The drive signal of the switching element can be modulated.
According to a nineteenth aspect, in the first to eighteenth aspects, the load comprises a discharge lamp. In the twentieth aspect, the control circuit controls the output of the inverter circuit according to the load current flowing through the discharge lamp. The crest factor of the lamp current flowing through the discharge lamp can be improved.

According to the twenty-first aspect, the twenty-first aspect or the second aspect
In a power supply device comprising a plurality of sets of a discharge lamp and an inverter circuit, wherein the plurality of inverter circuits share a switching element and a resonance circuit of the inverter circuit is connected in parallel, any one of the discharge lamps Is removed, the control circuit turns on the remaining discharge lamps and suppresses the upper limit value of the limiter unit so as to reduce the voltage between the outputs of the inverter circuit to which the removed discharge lamps are connected. Therefore, the output of the inverter circuit from which the discharge lamp has been removed can be reduced.

According to the twenty-second aspect of the present invention,
In the first aspect of the invention, since the load is a fluorescent lamp having a lamp impedance per unit length of about 8 Ω / cm or more excluding the base, a T5 lamp described later can be used as the load. According to the invention of claim 23, in the invention of claims 1 to 22, the inverter circuit has a first resonance system including a capacitor and an inductor, and is provided between a connection point of the rectification circuit and the smoothing capacitor and one end of the resonance system. An impedance element for feeding back a part of the high frequency power of the inverter circuit is connected, and the impedance element constitutes a second resonance system with the inductor. Can be further reduced.

[0031]

Embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 shows a circuit diagram of a power supply device of the present embodiment. The power supply is an AC power source AC, a rectifier DB for full-wave rectifying the input alternating-current power supply AC via the input filter F _1, is connected via a diode D ₁ between the output terminals of the full-wave rectifier DB A smoothing capacitor C ₁ , an inverter circuit 1 that converts a DC voltage smoothed by the smoothing capacitor C ₁ into a high-frequency voltage and supplies the high-frequency voltage to a lamp La as a load, and switching elements Q ₁ and Q ₂ of the inverter circuit 1 at high speed. Control circuit 2 that turns on and off alternately
It is composed of The lamp La is composed of a discharge lamp such as a fluorescent lamp.

In the inverter circuit 1, the smoothing capacitor C
A series circuit of switching elements Q ₁ and Q ₂ composed of, for example, MOS-FETs is connected in parallel with ₁ . The switching element Q ₂ is, via a capacitor C ₃ and the inductor L _1, is connected between the power source side end of both filaments of the lamp La. On the other hand, between the non-power side end of both filaments of the lamp La is connected to a capacitor C ₂ for resonance. The connection point between the inductor L ₁ and the lamp La is connected to the connection point between the full-wave rectifier DB and the diode D ₁ via a capacitor C ₄ as an impedance element. still,
In the present embodiment, the switching elements Q ₁ and Q ₂ are M
Although the OS-FET is used, the switching elements Q ₁ ,
Not intended to limit the Q ₂ to MOS-FET,
It goes without saying that a switching element such as a transistor may be used.

The control circuit 2 includes a detection unit 3 for detecting a rectified waveform of the full-wave rectifier DB, a limiter unit 4 for limiting the detection value of the detection unit 3 to a predetermined upper limit value _VH and a lower limit value _VL , A driving frequency controller 5 for setting the driving frequency of the switching elements Q ₁ and Q ₂ from the output of the section 4, and a timer section for generating a driving signal for the switching elements Q ₁ and Q ₂ based on the output of the driving frequency controller 5. 6 and a driver unit 7 that outputs a drive signal of the timer unit 6 to the switching elements Q ₁ and Q ₂ .

The operation of the control circuit 2 will be described with reference to the waveform diagrams of each section shown in FIG. The detection unit 3 includes a full-wave rectifier DB
Resistor R connected between the high-potential side output terminal of
_1, a series circuit of R _2, by applying the output voltage V ₁ of the full-wave rectifier DB by resistors R _1, R ₂ minute, and outputs a detection voltages V ₁ 'which is proportional to the voltages V _1. The limiter unit 4 includes a series circuit of transistors Q ₃ and Q ₄ connected between the emitters and a series circuit of resistors R _{3 to} R ₅ connected between the collectors of the transistors Q ₃ and Q _4. Q _3, the output voltage V ₁ of the detecting unit 3 to the emitter of Q ₄ is input. A series circuit composed of the resistor R ₃ to R ₅ is by applying a control voltage V _CC min, detection voltages V ₁ threshold V ₃ of ', V
₄ is set (V ₃ <V ₄ ). The base of transistor Q ₃ are connected to the connection point of the resistors R ₄ and R _5, the threshold value V
₃ is input, the base of the transistor Q ₄ are connected to the connection point of the resistors R ₃ and R _4, the threshold V ₄ is input.

Here, the detection voltage V ₁ ′ is lower than the lower limit value V _L =
When the voltage becomes lower than V ₃ −V _BE3 (V _BE3 is the voltage between the base and the emitter of the transistor Q ₃ ), the transistor Q ₃ is turned on, and the output V ₂ of the limiter unit 4 is clamped to the lower limit value _VL . Similarly, when the detection voltage V ₁ ′ is equal to the upper limit value V _H =
When the voltage becomes higher than V ₄ + V _BE4 (V _BE4 is the base-emitter voltage of the transistor Q ₄ ), the transistor Q ₄ is turned on, and the output V ₂ of the limiter unit 4 is clamped at the upper limit value V _H.

The driving frequency control unit 5 includes a fundamental frequency setting circuit 5a, an operational amplifier OP _1, the transistor Q ₅ to Q
Consists of _seven . The operational amplifier OP ₁ and the transistor Q ₅ constitutes a voltage-current converter circuit, generating a current I ₁ proportional to the output voltage V ₂ of the limiter unit 4. The transistors Q ₆ and Q ₇ constitute a current mirror circuit. When the current I ₁ flows through the transistor Q ₆ , substantially the same current as the current I ₁ also flows through the transistor Q ₇ . The collector of the transistor Q ₇ is a basic frequency setting circuit 5a for supplying a large current I ₂ than the current I _1, the transistor Q _8, Q _9, Q
_The current mirror circuit ₁₂ is connected to a current mirror circuit, and this current mirror circuit constitutes an input section of the timer section 6. The transistor Q ₈ is a current I ₂ and the difference current I ₃ of the current _{I 1 (= I 2 -I 1} ) flows, the current I ₃ becomes small when the output V ₂ of the limiter portion 4 is large, the output V ₂
Is smaller, the current I ₃ becomes smaller,
A current I ₃ having a shape similar to that of the output V ₂ of the limiter unit 4 flows through the transistor Q ₈ .

The timer section 6 includes a current mirror circuit composed of the above-described transistors Q ₈ , Q ₉ , and Q ₁₂ , a general-purpose timer integrated circuit (for example, μPC1555 manufactured by NEC) IC _{1, and the} like. And an astable multivibrator circuit. The frequency of the pulse voltage V ₆ outputted from the timer integrated circuit IC ₁ ', inversely proportional to the magnitude of the current I ₃ flowing through the transistor Q _8. Here, each resistance value of the resistors R ₆ , R ₇ and R ₈ is represented by R
₆ = R ₇ = 2R ₈ , the transistor Q
_A current substantially equal to the current I ₃ flowing through the transistor Q ₉
Flows to Also, when the discharge terminal DIS is connected to the ground within the timer integrated circuit IC _1, 2 times the current of the current I ₃ flows through the transistor Q _12. Here, the transistors Q ₁₀ and Q ₁₁ constitute a current mirror circuit, and the transistor Q ₁₁ has a transistor Q ₉
A current that is substantially equal to the current flowing through

Integrated circuit IC for timer₁The threshold
Of the terminal TH and the trigger terminal TRIG_FiveBut control
Voltage V_CCBetween approximately one third and approximately two thirds of
(V_CC/ 3 <V_Five<2V_CC/ 3), capacitor C_FiveIs
Transistor Q₁₁(Ie, the current I_Three)
Is charged by the capacitor C_FiveVoltage V_FiveRise
You. Voltage V_FiveIs the control voltage V_CCRises to 2 in about 3 minutes
And integrated circuit IC for timer₁Discharge terminal D
IS is connected to ground and transistor Q₁₂Current I
_ThreeTwice the current (2I_Three) Flows. Therefore, the tiger
Transistor Q₁₂Current (2I_Three) And transistor Q
₁₁Current I flowing through_ThreeCurrent (−I _Three) Is condensed
Sa C_FiveFlows from the capacitor C_FiveIs discharged and its both ends
Voltage V_FiveIs the control voltage V_CCTo about one third of So
And the voltage V_FiveIs the control voltage V_CCAbout one third of
Integrated circuit IC for timer₁Distorted inside
When the connection between the terminal DIS and the ground is disconnected, the capacitor C
_FiveIs charged again. By the way, the timer integrated circuit I
C₁Potential V of the output terminal OUT₆Is the capacitor C_Fiveof
During charging, the level is high and the discharge terminal DIS
Is connected to the ground and the capacitor C_FiveDischarges,
The potential of the output terminal OUT becomes low level. Accordingly
And the current I_ThreeIs small, the capacitor C_FiveRelease of
Since the power is supplied slowly, the voltage V₆Of the square wave signal
The wave number decreases and the current I_ThreeIs large, the capacitor
C_FiveIs rapidly charged and discharged.₆Square wave signal
Becomes higher.

The driver section 7 is composed of the drive integrated circuit IC ₂ of IR2111 such general purpose, at the timing of the square wave signal V ₆ outputted from the timer integrated circuit IC _1, alternately switching elements Q _1, Q ₂ On and off. The control circuit 2 controls the output voltage V
If ₂ is high (peak value near the AC power source AC, i.e., crests of the pulsating voltage V _1), decreases the current I ₃ by the current I ₁ is increased, the switching elements Q _1, Q
The driving frequency of ₂ becomes lower. On the other hand, when the output voltage V ₂ of the limiter portion 4 is low (AC power source AC zero cross vicinity, i.e., valleys of the pulsating voltage V _1), increases the current I ₃ by the current I ₁ is reduced , The driving frequency of the switching elements Q ₁ and Q ₂ increases. Further, the limiter portion 4, a pulsating voltage V ₁ of the full-wave rectifier DB in comparison with the threshold value V _3, V _4, the upper limit the upper and lower ripple voltages V ₁ V
_H, and waveform shaping to a voltage V ₂ which is clamped by the minimum value V _L, the control circuit 2 the frequency set by the fundamental frequency setting circuit 5a, is modulated in accordance with the output V ₂ of the limiter 4.

By the way, using a lamp La as a load,
When frequency modulation is not performed by detecting the output voltage V ₁ of the full-wave rectifier DB, that is, the switching elements Q ₁ and Q are always at the same frequency by the output of the basic frequency setting circuit 5a.
₂ is driven, the dimming lighting (FIG. 3B) is compared with the full lighting [FIG. 3A] compared with the basic frequency setting circuit 5a.
, The driving frequency of the switching elements Q ₁ and Q ₂ is increased, the effective value of the lamp current I _La of the lamp La is reduced, and the lighting output is reduced. However, at the time of dimming lighting, the lamp current I _La is reduced at the crest of the ripple voltages V _1, the ripple component of the lamp current I _La increases in the crest of the ripple voltages V ₁ and valleys,
The crest factor of the lamp current L _La deteriorates.

[0041] In the power supply device of this embodiment therefore, the control circuit 2 is increased lamp current I _La lowering the driving frequency f at a crest of the ripple voltages V _1, the driving frequency of the valley pulsating voltages V ₁ By increasing f and reducing the lamp current I _La , the ripple component of the lamp current L _La is reduced at the peaks and valleys of the pulsating voltage V ₁ , and the crest factor of the lamp current L _La is improved. .

That is, during the dimming lighting (FIG. 4B), the lamp current I _La is generated at the peak and the valley of the pulsating voltage V ₁ as compared with the full lighting (FIG. 4A). Since the ripple component to be increased becomes large, the voltage interval between the threshold values V ₃ and V ₄ of the limiter unit 4 is made wider than that at the time of full lighting, and the degree of frequency modulation is increased. I _La
The crest factor has been improved. Thus, by controlling the voltage interval between the threshold values V ₃ and V ₄ of the limiter unit 4, the ripple component of the lamp current I _La can be reduced. In order to widen the voltage interval between the threshold values V ₃ and V ₄ , it is only necessary to increase the resistance value of the resistor R ₄ and decrease the resistances R ₃ and R ₅ .

In the present embodiment, the control voltage V _{CC is changed} to the resistance R ₃
Although to R ₅ in dividing by setting the threshold V _3, V _4, the threshold V _3, V ₄ may be set individually by a separate circuit, the timer as long as performing the same operation Needless to say, the unit 6 may be realized by another configuration. Further, in the present embodiment, the lamp La such as a fluorescent lamp is used as the load, but the same effect can be obtained by using a load such as a resistance load. (Embodiment 2) power supply of the present embodiment, as shown in FIG. 5, the full-wave rectifier DB is composed of a diode D ₃ to D ₆ in the power supply apparatus of FIG 1, between the output terminals of the full-wave rectifier DB smoothing capacitor C ₁ is connected via the series circuit of the diode D _2, D _1. In the control circuit 2, individually the lower limit V _L and the upper limit value V _H of the limiter portion 4, or since combination is set, it is possible to improve the crest factor of various waveforms of the lamp current I _La.

The control circuit 2 detects the power supply voltage of the AC power supply AC and turns on and off the switching elements Q ₁ and Q ₂ alternately at a high speed. The operation of the control circuit 2 is shown in FIGS.
This will be described below. In the limiter unit 4, first, the gain adjustment circuit 4a outputs the output voltage V ₁ of the full-wave rectifier DB (ie,
The absolute value of the power supply voltage of the AC power supply AC) is amplified by a predetermined gain K. The limiter circuit 4b outputs the voltage V ₂ obtained by waveform shaping the voltage amplified by the gain adjustment circuit 4a at the lower limit value V _L and the upper limit value V _H.

Next, the adding circuit 8 adds the reference frequency voltage V _f0 to the output voltage V ₂ of the limiter unit 4 to generate a modulation signal V _f , and the voltage frequency conversion circuit 9 converts the modulation signal V _f into a frequency. Thereby, the driving frequency f of the switching elements Q ₁ and Q ₂ can be obtained. Then, the duty shaping circuit 10 generates a drive signal for the switching elements Q ₁ and Q ₂ based on the output signal of the voltage frequency conversion circuit 9, and the drive circuit 7 converts the drive signal for the duty shaping circuit 10 into the switching elements Q ₁ and Q ₁ . output to Q _2, turning on or off the switching elements Q _1, Q _2.

Here, FIG. 7 shows waveforms at various parts when the gain K of the gain adjustment circuit 4a is increased. If the gain K is increased, the period since the full-wave rectifier output voltages V ₁ the gain K times the value of the DB (K × V ₁₎ is increased, the output V ₂ of the limiter portion 4, which is clamped to the lower limit value V _L together is shortened, the period to be clamped is prolonged to the upper limit value V _H. The drive frequency control unit 5 outputs the output V ₂ of the limiter unit 4.
Drive frequency f of switching elements Q ₁ and Q ₂ based on
Is determined, the period during which the drive frequency f is constant is equal to that in FIG.
It is longer than. That is, by adjusting the gain K of the gain adjuster 4a, it is possible to adjust the period during which the drive frequency f is constant.

Further, shows a waveform of each part in the case of changing the lower limit value V _L and the upper limit value V _H of the limiter portion 4 in FIG. When narrowing the voltage range of the lower limit value V _L and the upper limit value V _H, the limiter portion 4 with peaks and valleys of the pulsating voltage V ₁ of the full-wave rectifier DB
The difference between the output V ₂ and the modulation signal f becomes smaller, the maximum value of the switching elements Q _1, Q ₂ of the driving frequency f (voltages V ₁
Difference crests) and the minimum value (valley voltages V ₁₎ is reduced in. Therefore, by changing the lower limit value V _L and the upper limit value V _H of the limiter portion 4, it is possible to adjust the driving frequency f.

As shown in FIG. 9, when the upper limit value V _H is higher than the value (K × V ₁ ) obtained by multiplying the rectified voltage V ₁ of the full-wave rectifier DB by the gain K in the gain adjusting unit 4a, the limiter unit output V ₂ of the 4 is clamped only at the lower limit value V _L, the driving frequency f is a convex waveform under the crest of the voltage V _1. Also, if the lower limit V _L of the limiter portion 4 was set to 0V, as shown in FIG. 10, the output V ₂ of the limiter portion 4 is clamped only by the upper limit value V _H, the driving frequency f voltages V ₁
Has an upwardly convex waveform at the valley portion. Of the lower limit value V _L and the upper limit value V _H of the limiter portion 4, if it is known that the frequency modulation is performed in either a range which only one of the boundary value to operate may be set to only one of the boundary value .

As described above, by setting the lower limit value _VL and the upper limit value _VH individually or in combination in the limiter section 4, it is possible to generate the modulation signal _Vf corresponding to the output of the lamp La. it can. In the present embodiment, the switching element Q based on the output voltage V ₂ of the limiter unit 4
_1, Q ₂ of which is molded a modulated signal V _f of the driving frequency f, but the switching elements Q _1, Q based on the output voltage V ₂
A signal for modulating the on / off duty ratio of ₂ may be shaped.

The power supply device of the first embodiment is the same as the power supply device of the first embodiment except for the configuration of the control circuit 2, and a description thereof will be omitted. Third Embodiment In the first and second embodiments, the drive frequency of the drive signal for the switching elements Q ₁ and Q ₂ is modulated. In the third embodiment, the on-duty of the drive signal is modulated.

The operation of the control circuit 2 will be described with reference to FIG. The limiter portion 4, similarly to Embodiment 2, the gain adjustment circuit 4a gain the output voltage V ₁ of the full-wave rectifier DB K
The limiter circuit 4b outputs a voltage V _{2 obtained} by shaping the output of the gain adjustment circuit 4a with the upper limit value V _H and the lower limit value _VL.
Is output. Adding circuit 8 adds the output V ₂ and the reference duty cycle signal V _{DT 0} of the limiter unit 4, it generates a duty signal V _DT.

On the other hand, the voltage frequency conversion circuit 9 converts a preset reference frequency voltage V _f0 into a frequency signal V _f , and the driving frequency of the switching elements Q ₁ and Q ₂ is set to a constant value. The duty shaping circuit 10 generates a drive signal based on the duty signal _VDT of the addition circuit 8 and the frequency signal _Vf of the voltage frequency conversion circuit 9, and the drive circuit 7 switches the switching element Q based on the drive signal of the duty shaping circuit 10. ₁ and Q ₂ are being driven.

FIG. 12 shows the waveforms of the respective parts when the on-duty modulation is performed in a region where the on-duty of the drive signal is 50% or less while the frequency of the drive signal for the switching elements Q ₁ and Q ₂ is constant. . At the peak of the pulsating voltage V ₁ of the full-wave rectifier DB, the output V ₂ of the limiter 4 is set to the upper limit V
Clamped to _H and set the duty signal _VDT of the adder circuit 8 to 5
By approaching 0%, the lamp current I _La flowing through the lamp _La is increased. On the other hand, in the valley ripple voltage V _1, clamping the limiter unit output V ₂ of the limiter portion 4 to the lower limit value V _L,
Lower the duty signal V _DT, thereby suppressing the lamp La of the lamp current I _La increases.

[0054] Incidentally, in the range duty signal V _DT is less 50%, Figure 1 when is the duty signal V _DT, a frequency-current characteristic of the lamp current I _La that flows through the lamp La
It is shown in FIG. The lamp current I _La is the voltage V _{1 of the} full-wave rectifier DB.
(The absolute value of the power supply voltage of the AC power supply AC),
Figure Lt. indicates frequency current characteristic in the mountain portion of the voltage V _1, Zuchuro shows a frequency-current characteristic in the valley voltage V _1. Further, the resonance frequency, the frequency f ₂ frequency f ₁ is at the peak portion of the voltages V ₁ denotes the resonance frequency in the valley voltages V _1.

As shown in FIG. 15, in the frequency range above the resonance frequencies f ₁ and f ₂ , the inverter circuit 1 operates in a phase-lag manner, and the lamp current I _La increases as the frequency f decreases, but the resonance frequencies f ₁ and f ₂ In the following frequency range, the inverter circuit 1 performs a phase leading operation, the lamp current I _La decreases as the frequency f decreases, and the relationship between the frequency f and the lamp current I _La reverses. In addition, when the inverter circuit 1 performs the phase advance operation, there is a problem that the switching loss increases.

Therefore, when the frequency f of the inverter circuit 1 changes in the commercial cycle of the AC power supply AC due to frequency modulation, the driving of the switching elements Q ₁ and Q ₂ of the inverter circuit 1 is performed so that the inverter circuit 1 does not perform the phase advance operation. The frequency is set in a frequency range equal to or higher than the resonance frequencies f ₁ and f ₂ . By the way, the output voltage V ₁ of the full-wave rectifier DB
FIG. 16 shows waveforms of respective parts when frequency modulation is performed in inverse proportion to (the absolute value of the power supply voltage V _IN of the AC power supply AC).

Here, the resonance frequency changes between f ₁ and f ₂ according to the peak and valley of the voltage V ₁ , but since the proportional gain is reduced, the frequency f is the resonance frequency at the peak of the voltage V _1. f ₁ or more, in the valley voltages V ₁ becomes the resonance frequency f ₂ or more, can be set higher than the inverter circuit is always a resonance frequency f ₁ of the driving frequency f of 1, f _2. Therefore, the inverter circuit 1 always operates in a phase-lag manner, and when the driving frequency f of the inverter circuit 1 decreases, the lamp current I _La increases.

FIG. 17 shows waveforms at various parts when frequency modulation is performed in inverse proportion to the output voltage V ₁ of the full-wave rectifier DB and the proportional gain is increased. In this case, although the proportional gain is increased, the drive frequency f of the inverter circuit 1 is increased.
Which then sets an upper limit value f _H and the lower limit f _L, when the driving frequency f is lower than the lower limit f _L, and a limiter unit of the lower limit is operated, the driving frequency f is clamped to the lower limit f _L .
With increasing, but the lamp output of the lamp La increases, exceeds 50% duty signal V _DT, along with the increase of the duty signal V _DT, since lamp output is reduced, the upper limit value of the duty signal V _DT 50% It is set to the following value. Further, if the duty signal _VDT is set to a value less than 25%, zero current switching may not be performed due to the influence of higher harmonics of the oscillation frequency of the inverter circuit 1, so that the lower limit of the duty signal _VDT Value is 2
It is set to a value of 5% or more.

On the other hand, FIG. 13 shows waveforms of the respective parts when the on-duty modulation is performed in a region where the on-duty of the driving signal is 50% or more while the frequency of the driving signal for the switching elements Q ₁ and Q ₂ is constant. When the on-duty becomes 50% or more, the relationship between the on-duty and the lamp output is reversed, so the lower limit of the duty signal _VDT is set to a value of 50% or more. When the duty signal _VDT is 75
%, The upper limit value of the duty signal _VDT is set to a value of 75% or less because zero current switching may not be performed due to the influence of higher harmonics of the oscillation frequency of the inverter circuit 1. .

The configuration other than the control circuit 2 is the same as that of the second embodiment.
Therefore, the description is omitted. (Embodiment 4) FIG. 14 is a circuit diagram of a power supply device according to this embodiment.
Shown in When the driving frequency of the switching elements Q ₁ and Q ₂ constituting the inverter circuit 1 is changed, the lamp L
FIG. 15 shows the frequency current characteristics of the lamp current I _La flowing through the line a. The lamp current I _La changes according to the voltage V ₁ of the full-wave rectifier DB (the absolute value of the power supply voltage of the AC power supply AC), and A in the figure shows the frequency current characteristics at the peak of the voltage V ₁ . shows the frequency-current characteristic in the valley voltage V _1. Further, the resonance frequency, the frequency f ₂ frequency f ₁ is at the peak portion of the voltages V ₁ denotes the resonance frequency in the valley voltages V _1.

As shown in FIG. 15, in the frequency range above the resonance frequencies f ₁ and f ₂ , the inverter circuit 1 operates in a phase-lag manner, and the lamp current I _La increases as the frequency f decreases, but the resonance frequencies f ₁ and f ₂ increase. In the following frequency range, the inverter circuit 1 performs a phase leading operation, and the lamp current I _La decreases as the frequency f decreases, and the relationship between the frequency f and the lamp current I _La reverses. In addition, when the inverter circuit 1 performs the phase advance operation, there is a problem that the switching loss increases.

When the frequency f of the inverter circuit 1 changes in the commercial cycle of the AC power supply AC due to the frequency modulation, the driving of the switching elements Q ₁ and Q ₂ of the inverter circuit 1 is performed so that the inverter circuit 1 does not perform the phase advance operation. The frequency is set in a frequency range equal to or higher than the resonance frequencies f ₁ and f ₂ . By the way, the output voltage V ₁ of the full-wave rectifier DB
FIG. 16 shows waveforms of respective parts when frequency modulation is performed in inverse proportion to (the absolute value of the power supply voltage V _IN of the AC power supply AC).

Here, the resonance frequency changes between f ₁ and f ₂ according to the peak and valley of the voltage V ₁ , but since the proportional gain is reduced, the frequency f is the resonance frequency at the peak of the voltage V _1. f ₁ or more, in the valley voltages V ₁ becomes the resonance frequency f ₂ or more, can be set higher than the inverter circuit is always a resonance frequency f ₁ of the driving frequency f of 1, f _2. Therefore, the inverter circuit 1 always operates in a phase-lag manner, and when the driving frequency f of the inverter circuit 1 decreases, the lamp current I _La increases.

FIG. 17 shows waveforms at various portions when frequency modulation is performed in inverse proportion to the output voltage V ₁ of the full-wave rectifier DB and the proportional gain is increased. In this case, although the proportional gain is increased, the drive frequency f of the inverter circuit 1 is increased.
Which then sets an upper limit value f _H and the lower limit f _L, when the driving frequency f is lower than the lower limit f _L, and a limiter unit of the lower limit is operated, the driving frequency f is clamped to the lower limit f _L .

That is, the pulsating voltage V ₁ of the full-wave rectifier DB
In the mountain part, in order to increase the lamp current I _La, by lowering the driving frequency f of the inverter circuit 1, causes clamped by the minimum value f _L, in the valley ripple voltage V _1, the lamp current I _La In order to suppress the increase, the inverter circuit 1
By increasing the drive frequency f, it is performed frequency modulation so as to clamp at the upper limit value f _H. At this time, the driving frequency f
Lower limit value f _L to a value equal to or higher than resonance frequency f ₁ and upper limit value f _H
Is set to a value equal to or higher than the resonance frequency f ₂ , the driving frequency f does not become equal to or lower than the resonance frequencies f ₁ and f _2, and the phase advance operation of the inverter circuit 1 can be prevented.

In the present embodiment, since the inverter circuit 1 always operates in a delayed phase, if the drive frequency of the switching elements Q ₁ and Q ₂ of the inverter circuit 1 is reduced, the lamp La
It is possible to increase the lamp current I _La flowing through. In addition, it is also possible to reduce the switching loss that occurs when the inverter circuit 1 is operated in the leading phase. Note that the configuration other than the control circuit 2 is the same as that of the first or second embodiment, and a description thereof will be omitted. Embodiment 5 In the present embodiment, in the power supply device of Embodiment 4, the control circuit 2 performs duty modulation in addition to frequency modulation.

FIG. 18 shows waveforms at various parts when the control circuit 2 performs only frequency modulation. The full-wave rectifier crest of the pulsating voltage V ₁ of the DB, by lowering the driving frequency f of the switching element Q _1, Q _2, has increased the lamp La of the lamp current I _La. On the other hand, in the valley ripple voltage V _1, by increasing the driving frequency f of the switching element Q _1, Q _2, is suppressed an increase in the lamp current I _La.

However, in the valley of the pulsating current V ₁ , the driving frequency f of the inverter circuit 1 is clamped at the upper limit value f _H. Therefore, the driving frequency f is set to a value higher than this, and the lamp current I _La Cannot be reduced, and the lamp current I
_La is increasing compared to the peak of the pulsating current. Therefore, in the present embodiment, when the drive frequency f of the switching elements Q ₁ and Q ₂ constituting the inverter circuit 1 reaches the upper limit value f _H , the control circuit 2 reduces the on-duty of the switching elements Q ₁ and Q ₂ . Duty modulation is performed. That is, until the drive frequency f reaches the upper limit f _H, the control circuit 2 is set to on-duty to a predetermined value d ₂ of 50% or less, when the drive frequency f reaches the upper limit f _H, the control circuit 2 is lowered on-duty gradually from d ₂ to _{d 1 (d 1 <d 2} <50%).

Therefore, when the drive frequency f reaches the upper limit value f _H during the valley of the pulsating current V ₁ , the control circuit 2 gradually reduces the on-duty D _ON from d ₂ to d _1. than when clamped to the upper limit value f _H and f, it is possible to further suppress the increase in the lamp current I _La, the crest factor of the lamp current I _La can be further improved.

In the control circuit 2 described above, the control circuit 2 performs on-duty modulation at the peak of the pulsating voltage V ₁ ,
Although the crest factor of the lamp current I _La is improved by further suppressing the increase of the lamp current I _La of the lamp La, the control circuit 2 is turned on at the valley of the pulsating voltage V _1. Perform duty modulation and adjust the lamp L
By further increasing the lamp current I _La of a
The crest factor of the lamp current I _La may be improved.

As shown in FIG. 20, the control circuit 2 modulates the drive frequency f of the switching elements Q ₁ and Q ₂ of the inverter circuit 1 in inverse proportion to the pulsating voltage V _1. above the f _H, the upper limit value f the driving frequency f
_H and the drive frequency f is lower than the lower limit f _L
Below the, the driving frequency f is clamped to the lower limit f _H,
The crests of the pulsating voltages V ₁ increases the lamp La of the lamp current I _La, the valley pulsating voltages V ₁ and suppresses the increase of the lamp La in the lamp current I _La.

Here, while the drive frequency f is not clamped to the lower limit value f _L , the control circuit 2 sets the on-duty of the switching elements Q ₁ and Q ₂ to a predetermined value d of 50% or less.
Set to ₁ . In the mountain part of the pulsating voltage V _1, the control circuit 2 lowers the drive frequency f, when the driving frequency f is clamped to the lower limit f _L, the control circuit 2 the on-duty of the switching elements Q _1, Q ₂ d ₁ to d ₂ (d ₁
<D ₂ <50%) to gradually increase the pulsating voltage V ₁
The lamp current I _La at the peak of is increased. Therefore, the difference between the lamp current I _{La at} the peak and the valley of the pulsating voltage V ₁ can be reduced, and the crest factor can be further improved.

[0073] Furthermore, the control circuit 2 described above, the crests or valleys of the pulsating voltage V _1, only while the driving frequency f is clamped to the upper limit value f _H or the lower limit value f _L, the control circuit 2 Although on-duty modulation is performed, the pulsating voltage V ₁
On-duty modulation may be performed in the entire region of. As shown in FIG. 21, the control circuit 2 controls the pulsating voltage V ₁
, The drive frequency f of the switching elements Q ₁ and Q ₂ is modulated, and the on-duty is modulated in proportion to the pulsating voltage V ₁ . Then, the driving frequency f is beyond the upper limit value f _H, the driving frequency f is clamped to the upper limit value f _H, the driving frequency f is below the lower limit f _L, clamp the driving frequency f to the lower limit f _H. When the on-duty exceeds a predetermined value d ₂ of 50% or less, the control circuit 2
Clamps the on-duty to d ₂ , and when the on-duty falls below a predetermined value d ₁ lower than d ₂ , the control circuit 2
To clamp the on-duty to d _1.

As described above, at the peak portion of the pulsating voltage V ₁ , the control circuit 2 lowers the drive frequency f to the lower limit value f _L and increases the on-duty to d ₂ .
The lamp current I _La is increased, and in the valley of the pulsating voltage V ₁ ,
Since the control circuit 2 suppresses the increase of the lamp current I _La by increasing the drive frequency f to the upper limit value f _H and decreasing the on-duty to d ₁ , the peak and the valley of the pulsating current V ₁ are reduced. and the difference between the lamp current I _La can the be further reduced, the crest factor of the lamp current I _La can be further improved.

Note that the circuit configuration and operation of the power supply device other than the control circuit 2 are the same as those of the first to fourth embodiments, and a description thereof will be omitted. (Embodiment 6) In the present embodiment, in the power supply device of Embodiment 1, the control circuit 2 controls the power consumption of the load to be constant with respect to the voltage fluctuation of the AC power supply AC.

In the power supply device of the first embodiment, the AC power supply AC
Since generating a threshold V _3, V ₄ of the limiter portion 4 by dividing the control voltage V _CC of the separate power supply by a resistor R ₃ to R ₅ and, as shown in FIG. 22 (a) (b) , Full-wave rectifier DB
The threshold voltages V ₃ and V ₄ of the limiter unit 4 do not change even if the pulsating current voltage V ₁ changes. The threshold values V ₃ and V _{4 of} the limiter unit 4, that is, the lower limit value _VL and the upper limit value _VH are
Since correspond respectively to the upper limit value f _H and the lower limit f _L of the driving frequency f of the inverter circuit 1, even pulsating voltage V ₁ is varied, the modulation width of the frequency modulation of the control circuit 2 is substantially constant . Therefore, when the power supply voltage of the AC power supply AC fluctuates, the drive frequency f of the inverter circuit 1 is constant, so that the output voltage of the inverter circuit 1 also fluctuates.

[0077] In particular, when a lamp of a discharge lamp such as a load, the peak value of the pulsating current voltages V ₁ as shown in FIG. 22 (a) is lowered, the inverter circuit 1 in the mountain portion of the pulsating voltages V ₁ Output drops. When the output of the inverter circuit 1 decreases, the lamp impedance increases, and the output of the inverter circuit 1 further decreases. For this reason, the difference between the lamp current I _La at the peak and the valley of the pulsating current V ₁ becomes large, which is not much different from the lamp current I _La of the conventional power supply device in which the drive frequency f is not modulated.

Therefore, as shown in FIG. 23 (a), when the peak value of the pulsating voltage V ₁ decreases, the upper limit value V _H is increased, and when the peak value of the pulsating voltage V ₁ is high [ FIG.
(B)], the difference dV between the upper limit value _VH and the lower limit value _VL of the limiter circuit 4 is increased. By increasing the upper limit value V _H of the limiter unit circuit 4, the lower limit value f _L of the drive frequency f can be set to a lower frequency, and the frequency modulation width (that is, the lower limit value f _L of the drive frequency f and the upper limit value of the drive frequency f) can be set. the difference between the value f _H) is increased. Therefore, the crests of the pulsating voltages V _1, the lamp the lamp current I _La it is possible to increase the flow to La, be pulsating voltage V ₁ is varied, making the output power of the inverter circuit 1 substantially constant Can be.

As described above, by changing the modulation width of the drive frequency f of the inverter circuit 1 in accordance with the voltage fluctuation of the pulsating voltage V ₁ (that is, the absolute value of the AC power supply AC), the pulsating voltage V ₁ , The output power of the inverter circuit 1 can be made substantially constant. (Embodiment 7) In the power supply device of Embodiment 1, the AC power supply A
When the power supply voltage of C (that is, the pulsating voltage V ₁ ) fluctuates, the output V ₂ of the limiter unit 4 changes to the upper limit value V _H or the lower limit value V
_The periods T _H and T _{L that} are clamped at _L fluctuate. For example, as shown in FIG. 25 (b), as compared in FIG. 25 (a), even if the peak value of the pulsating voltage V ₁ is increased, the upper limit V ₄ and the lower limit value V _L of the limiter portion 4 is changed Not
Period T _H of the output V ₂ of the limiter portion 4 is clamped by the upper limit value V ₄ becomes longer, the period T _L that is clamped by the lower limit value V _L becomes shorter. Therefore, when the pulsating voltage V ₁ increases, the control circuit 2 controls the output of the inverter circuit 1 to increase. When the pulsating current voltage V ₁ is smaller in the opposite, the period T _H of the output V ₂ of the limiter portion 4 is clamped by the upper limit value V _H is shortened, since the period T _L that is clamped by the lower limit value V _L becomes longer, The control circuit 2 controls the output of the inverter circuit 1 so as to decrease. Therefore, the output power of the inverter circuit 1 by variation of the pulsating voltages V ₁ also varies.

Therefore, in this embodiment, as shown in FIG.
Thus, the full-wave rectifier DB and the diode D₁Connection points and graphs
Diode D₈And resistance R₉, R_TenDirectly
Connected to the column and the resistor R_TenAnd a capacitor C in parallel₆Connect
And the pulsating voltage V₁Is the resistance R₉, R_TenAnd divide the pressure
Densa C₆And the reference voltage V_C6Raises this criterion
Voltage V_C6Is the resistance R_Three~ R_FiveAnd the voltage is divided by the limiter circuit.
Threshold V of 4_Three, V_FourIs set. Therefore,
Ripple voltage V₁Fluctuates, the threshold value V_Three, V _Four,sand
That is, the lower limit value V_LAnd upper limit value V_HAlso pulsating voltage V₁According to
Fluctuate. Therefore, the resistance R_Three~ R_FiveThe resistance value of
26 (a) and 26 (b) by designing
As shown, the pulsating voltage V₁Even if the peak value of
Output V of the transmitter 4_TwoIs the upper limit value V_HOr lower limit value V_LNiku
Period T to be ramped_H, T_LCan be approximately constant
You.

In general, when the power supply voltage of the AC power supply AC increases, the power consumption of the load also increases. When the power supply voltage of the AC power supply AC decreases, the power consumption of the load also decreases. with, as pulsating voltage V ₁ of the rectifier DB than the rate of change, the upper limit value V _H and the lower limit value V _L of the limiter portion 4 is changed in a large proportion,
The resistor R ₃ to R ₅ may be set. That is, FIG.
As shown in (a) (b), when the pulsating voltage V ₁ is increased, the clamp contrary to the case shown in FIG. 27 (a) (b), the output V ₂ of the limiter portion 4 to the upper limit value V _H Period T _H
Together with shortening, the output V ₂ is longer period T _L that is clamped to the lower limit value V _L, the inverter circuit 1
It can be the driving frequency of a longer period to be clamped to the upper limit value f _H, to reduce the rate of increase in the output of the inverter circuit 1 by increasing the pulsating voltage V _1.

[0082] Similarly, when the pulsating voltages V ₁ decreases, with a longer period T _H of the output V ₂ of the limiter portion 4 is clamped to the upper limit value V _H, the output V ₂ is clamped to the lower limit value V _L since the shorter period T _L that, the driving frequency of the inverter circuit 1 is clamp period becomes longer to the lower limit value f _L, to reduce the rate of decrease in the output of the inverter circuit 1 due to a decrease in pulsating voltages V ₁ Can be. Therefore,
Fluctuations in the output of the inverter circuit 1 due to fluctuations in the power supply voltage of the AC power supply AC can be suppressed.

In the present embodiment, the voltage V _C6 obtained by dividing and smoothing the pulsating voltage V ₁ is _divided by the resistors R _{3 to} R ₅ , so that the threshold values V ₃ , V ₄ , That is, although the lower limit value _VL and the upper limit value _VH are generated, the pulsating voltage V
₁ (i.e., the AC power source AC) voltage that changes according to the voltage variation of, may be given to the lower limit value V _L and the upper limit value V _H by another circuit. In (Embodiment 8) Embodiment 7, the pulsating voltages V ₁ resistor R
_The DC voltage V _C6 obtained by dividing and smoothing the voltage by a circuit composed of the capacitors ₉ , R ₁₀ and the capacitor C _{6 is divided} by the resistors R _{3 to} R ₅ , so that the lower limit value _VL and the upper limit value V
While setting the _H, in the present embodiment, as shown in FIG. 28, the resistance of the smoothed voltage of the smoothing capacitor C ₁ R ₃ ~R ₅
By dividing in, and set the lower limit V _L and the upper limit value V _H of the limiter unit 4.

The inverter circuit 1 includes a smoothing capacitor C ₁
Since operating the smoothed voltage as a power supply, the output of the inverter circuit 1 is affected by the voltage ripple of the smoothing capacitor C _1. In the present embodiment, by dividing the smoothed voltage of the smoothing capacitor C ₁ by a resistor R ₃ to R _5, since the set lower limit value V _L and the upper limit value V _H of the limiter portion 4, as in Embodiment 7 a decline voltage across the smoothing capacitor C ₁ is,
The lower limit V _L and the upper limit value V _H of the limiter portion 4 is lowered,
The output V ₂ of the limiter portion 4 is longer period T _H which is clamped to the upper limit value V _H, the output V ₂ is shortened period T _L that is clamped to the lower limit value V _L, the inverter circuit 1 The drive frequency is reduced to the lower limit value f _L , the clamp period is lengthened, and the rate at which the output of the inverter circuit 1 decreases can be reduced.

[0085] Also, when the smoothed voltage of the smoothing capacitor C ₁ is increased, the lower limit value V _L and the upper limit value V _H of the limiter portion 4 is increased, the output V ₂ of the limiter portion 4 is clamped to the upper limit value V _H thereby shortening the period T _H, the output V ₂ is longer period T _L that is clamped to the lower limit value V _L, the driving frequency of the inverter circuit 1 becomes long clamp period to the upper limit value f _H, the inverter circuit 1 can reduce the rate of increase.

Therefore, by setting the upper limit value V _H and the lower limit value _VL of the limiter unit 4 based on the voltage ripple of the smoothing capacitor C ₁ , the output of the inverter circuit 1 due to the fluctuation of the power supply voltage of the AC power supply AC is set. Can be corrected. The configuration other than the limiter unit 4 is as follows.
Since it is the same as the first or seventh embodiment, the description is omitted. (Embodiment 9) In this embodiment, as in Embodiment 1,
By modulating the drive frequency of the switching elements Q ₁ and Q ₂ to reduce the fluctuation of the lamp current due to the peak and valley of the pulsating voltage V ₁ , and controlling the on-duty of the switching elements Q ₁ and Q ₂ , the pulsating voltage thereby reducing variations in the output inverter circuit 1 according to the voltage variation of V _1.

In the present embodiment, as shown in FIG. 29, in the power supply device of the seventh embodiment, the timer section 6 changes the drive frequency of the switching elements Q ₁ and Q ₂ according to the voltage V _C6 across the capacitor C _6. Frequency modulator 6a for modulating
And a duty modulator 6b that modulates the on-duty of the switching elements Q ₁ and Q ₂ according to the voltage V _C6 across the capacitor C ₆ .

[0088] Frequency modulation unit 6a, as described in Embodiment 1, astable composed transistors Q _8, Q _9, a current mirror circuit composed of Q _12, timer integrated circuit IC ₁ like And a vibrator circuit. The duty modulation section 6b includes the transistor Q ₁₃
, Q ₁₆ , resistor R ₉ , capacitor C _7, and a general-purpose timer integrated circuit (for example, μPC155 manufactured by NEC Corporation).
5) consists of IC _3. When the output signal V ₆ to the trigger terminal TRIG the timer integrated circuit timer integrated circuit IC ₃ from IC ₁ of the frequency modulation unit 6a is inputted, timer integrated circuit IC ₃ is the falling of the output signal V _6, timer discharge terminal DIS in internal use integrated circuit IC ₃ is disconnected from the ground GND, the discharge terminal DIS and a threshold terminal TH is connected, the capacitor C ₇ connected between the terminals DIS and TH and the ground GND through the transistor Q ₁₆ It is charged by the flowing current.

[0089] Incidentally, the collector of the transistor Q ₁₃ is connected to a connection point of the capacitor C ₆ and a resistor R ₉ via the resistor R _12, the pulsating voltage to the transistor Q ₁₃ by the voltage across V _C6 of the capacitor C ₆ current proportional to V ₁ flows. Then, by the current mirror circuit consisting of a current mirror circuit and the transistor Q _15, Q ₁₆ comprising transistors Q _13, Q _14, current flowing through the transistor Q ₁₃ is transmitted to the transistor Q _16. Thus, the capacitor C ₇ is charged by a current proportional to the pulsating voltage V _1, the voltage of the threshold terminal TH reaches 2 approximately 3 minutes of the control voltage V _CC, the discharge terminal within the timer integrated circuit IC ₃ DIS is connected to the ground GND capacitor C ₇ and is discharged. When the voltage of the threshold terminal TH decreases to approximately one third of the control voltage V _CC , the discharge terminal DIS and the ground GND
Out is connected, the capacitor C ₇ is charged again.

Output terminal OU of timer integrated circuit IC ₃
Potential of T, the charging time of the capacitor C ₇ is a high level, a period of rest is at a low level. Therefore, when the pulsating voltage V ₁ is increased, the charging current of the capacitor C ₇ is increased, the charging period of the capacitor C ₇ is shortened, the time output of the timer integrated circuit IC ₃ is at high level (on-duty) Is also shorter. Conversely, when the pulsating voltages V ₁ decreases, the charging current of the capacitor C ₇ is reduced, because the charging period of the capacitor C ₇ is increased, the on-duty is the longer.

[0091] Therefore, when the pulsating voltage V ₁ is the lowest voltage of the allowable variation range, the on-duty of the output signal of the timer integrated circuit IC ₃ sets the charging current of the capacitor C ₇ such that the 50% if, when the pulsating voltages V ₁ is lowered, together with the on-duty is increased load output close to 50%, when the pulsating voltages V ₁ becomes higher, the load output is on-duty is lower than 50% since reduced, it is possible to correct the variation of the load output due to variations in the pulsating voltage V _1.

In the power supply device according to the sixth or seventh embodiment, the ripple component of the load output generated by the pulsating flow of the power supply voltage is frequency-controlled, and the voltage fluctuation of the power supply voltage is also controlled by the frequency control. For a load whose output fluctuates greatly due to fluctuation, the frequency must be largely fluctuated and the output may not be sufficiently corrected. In this embodiment, the load output is corrected by on-duty modulation. Therefore, it is possible to sufficiently cope with a load whose output fluctuates due to power supply voltage fluctuation.

A circuit other than the circuit shown in FIG. 29 may be used as long as the circuit modulates the on-duty so that the load output is corrected according to the voltage fluctuation of the AC power supply AC.
Needless to say. The configuration other than the duty modulation unit 6b is the same as that of the first or seventh embodiment, and a description thereof will not be repeated. (Embodiment 10) FIG. 3 is a circuit diagram of a power supply device of this embodiment.
0 is shown.

The inverter circuit 1 includes a smoothing capacitor C ₁
Switching elements Q ₁ and Q ₂ connected between both ends of the
The inductor L is connected in series between the source and the drain of the switching element Q _{2 1} and the first consisting of the capacitor C ₂
A resonance system, the inductor L ₂ across capacitor C ₂
And a lamp La connected as a load between the power supply side ends of both filaments via a capacitor C ₃ and a lamp La.
The capacitor C ₈ connected between the non-power supply side end of both filaments, the inductor L ₁ and between the connection points to the direction in which current flows to the junction of capacitor C ₁ and the switching element Q ₁ from the connection point of the capacitor C ₂ a diode D ₉ which is connected to, is composed of a capacitor C ₂ and connected in antiparallel diodes D ₁₀ Prefecture, the second resonance system is composed of the inductor L ₂ and capacitor C ₈ Prefecture. here,
Diode D _9, D _10, respectively, inductor L ₁ and capacitor C ₁ potential V _a of the connection point of the capacitor C ₂
Clamp to the voltage and ground level.

[0095] In the inverter circuit 1 of Embodiment 1, whereas have improved input power factor by feeding back the load voltage, the inverter circuit 1 of this embodiment, the feedback voltage across V _a of the capacitor C ₂ The input power factor has been improved. Also,
By providing the second resonance system in the inverter circuit 1 of the present embodiment, the feedback voltage V is somewhat independent of the load voltage.
it is possible to set the frequency characteristic of _a, especially when using a lamp load of the discharge lamp such as a lamp load when a load such as is light when preheating the smoothing capacitor C ₁ by reducing the voltage V _a Voltage rise can be prevented.

By the way, at the peak of the pulsating voltage V ₁ ,
Or larger than the amplitude increases and the voltage of the smoothing capacitor C ₁ of the voltage V _a, becomes lower than the ground level, the diode D ₉ or D ₁₀ of turned on, the voltage a voltage of the smoothing capacitor C ₁ of the voltage V _a Alternatively, it is clamped to the ground level and its amplitude is kept substantially constant. Therefore, the voltage V
ripple component of _a is lowered, the second of the voltage V _a power supply
In the above resonance system, at the time of full lighting (FIG. 31A), the crest factor of the current I _La flowing through the lamp La is improved to some extent.

[0097] However, when the resonance of the first resonant system consisting of an inductor L ₁ and capacitor C _2, such as during dimming lighting [FIG 31 (b)] becomes weak, the amplitude of the voltage across V _a of the capacitor C ₂ is small becomes, the voltage V _a is no longer clamped to the voltage or the ground of the capacitor C ₁ by the diode D _9, D _10. Therefore, when the driving frequency of the inverter circuit 1 is constant, the voltage V ripple component of _a is increased, the lamp current I in substantially anti shape similar pulsating current voltage V ₁ in the same manner as the inverter circuit 1 of Embodiment 1 _La flows and the crest factor deteriorates rapidly.

[0098] Therefore, in the present embodiment, similarly to Embodiment 1, the inverter circuit 1 in the mountain portion of the pulsating voltages V ₁
With increasing lamp current I _La lowering the driving frequency of, since lowering the lamp current I _La by increasing the driving frequency at the valleys of the pulsating voltage V _1, the lamp current I _La
Can be reduced to improve the crest factor. Further, the crest factor of the lamp current at the time of dimming lighting can be further improved by increasing the degree of frequency modulation at the time of dimming lighting than at the time of full lighting.

Since the configuration other than the inverter circuit 1 is the same as that of the first or seventh embodiment, the description is omitted. Further, although the control circuit of the seventh embodiment is applied to the inverter circuit 1 of the present embodiment, it goes without saying that the same effect can be obtained by applying any of the control circuits of the first to ninth embodiments. . (Embodiment 11) FIG. 3 is a circuit diagram of a power supply device according to this embodiment.
It is shown in FIG.

In the present embodiment, the control circuit 2 of the seventh embodiment is applied to the power supply device of FIG. 57 described in the conventional example, and, as in the first embodiment, at the peak of the pulsating voltage V ₁ , Since the driving frequency of the inverter circuit 1 is decreased to increase the lamp current I _La, and at the peak of the pulsating voltage V ₁ , the driving frequency of the inverter circuit 1 is increased to decrease the lamp current I _La. The crest factor of the current I _La can be improved. Further, the lamp L
By increasing the degree of frequency modulation at the time of dimming lighting than at the time of full lighting of a, the lamp current I at the time of dimming lighting is increased.
_La crest factor can be improved.

The configuration of the inverter circuit 1 is the same as that shown in FIG. 53, and the configuration other than the inverter circuit 1 is the same as that of the seventh embodiment, so that the description thereof is omitted. In the present embodiment, the control circuit 2 of the seventh embodiment is applied to the power supply device of FIG. 53. Needless to say. (Embodiment 12) FIG. 3 is a circuit diagram of a power supply device according to this embodiment.
3 is shown.

[0102] In the present embodiment, in the power supply device of Embodiment 11, the capacitor C _1, the diode from the capacitor C ₁ between C ₉ in the direction in which a current flows to the capacitor C ₉ D ₁₁
Insert the connect a capacitor C ₁₃ in parallel with the diode D ₁₁ and the capacitor C _9, the switching elements Q _1, Q ₂
The diode D ₁₁ connection points via a diode D ₁₀ and the inductor L ₂ and are connected to the connection point of the capacitor C _1. A diode D ₁₀ represent respectively the particle diameters switching element Q _1,
Current from the connecting point Q ₂ 'to the connection point of the diodes D ₁₁ and the capacitor C ₁ is inserted in the direction of flow.

In this embodiment, a step-down chopper is constituted by the diodes D ₁₀ and D ₁₁ , the inductor L ₂ and the smoothing capacitor C _1, and the smoothing voltage of the smoothing capacitor C ₁ is reduced.
The input power factor distortion has been improved. Similarly to the first embodiment, at the peak of the pulsating voltage V ₁ , the drive frequency of the inverter circuit 1 is reduced to increase the lamp current I _La, and at the peak of the pulsating voltage V ₁ , the inverter circuit 1
Is increased to lower the lamp current I _La , so that the crest factor of the lamp current I _La can be improved. Furthermore, the crest factor of the lamp current I _La during dimming operation can be improved by increasing the degree of frequency modulation during dimming operation rather than at full operation of the lamp _La .

Since the configuration other than the inverter circuit 1 is the same as that of the seventh or eleventh embodiment, the description is omitted.
In the present embodiment, the control circuit 2 of the seventh embodiment is used. However, it goes without saying that the same effect can be obtained by using any of the control circuits of the first to ninth embodiments. (Embodiment 13) FIG. 3 is a circuit diagram of a power supply device according to this embodiment.
FIG. 35 shows the waveform of each part in FIG.

The detecting section 3 detects the pulsating voltage V of the full-wave rectifier DB.
A detection voltage V ₁ ′ obtained by dividing ₁ by the resistors R ₁ and R ₂ is output to the inverting input terminal of the comparator CP ₁ . The control voltage V _CC is connected to the ratio inverting input terminal of the comparator CP ₁ with a resistor R.
_3, the voltage V ₇ obtained by dividing by R ₄ minutes _{[= V CC × R 4 / (} R 3 +
R ₄ )] is input, and the comparator CP ₁ compares the voltage V ₁ ′ with the voltage V ₇ .

[0106] The output terminal of the comparator CP ₁ is connected to the base of the transistor Q _5, when the output of the comparator CP ₁ is at the low level, the transistor Q ₅ is turned off, the transistor Q ₅ when the output is at the high level of the comparator CP ₁ is oN, current I ₁ flows through the transistor Q _6. The transistors Q ₆ and Q _{7 form} a current mirror circuit, and the collector of the transistor Q ₇
Basic frequency setting circuit 5a for supplying a current larger than ₁
Connected to. In addition, the collector of the transistor Q ₇ is,
The current mirror circuit is connected to a current mirror circuit composed of transistors Q ₈ , Q ₉ , and Q ₁₂ , and this current mirror circuit constitutes an input section of the timer section 6. The transistor Q ₈ has a difference between the current I ₂ and the current I _1. current _{I 3 (= I 2 -I 1} ) flows.

The period T during which the voltage V ₁ ′ is smaller than the voltage V ₇
In _L, the transistor Q ₅ is turned off, the current I ₁ does not flow, the current I ₃ is equal to the current I _2. On the other hand, the larger the period T _H than the voltage V ₁ 'voltage V _7, the transistor Q ₅ is turned on, a current I ₁ flows, the difference between the current I ₂ and the current I ₁ is the current I ₃ (I ₂ - The current of I ₁ ) flows.

Here, since the driving frequency of the switching elements Q ₁ and Q ₂ is determined by the current I ₃ as described in the first embodiment, during the period T _L where the current I ₃ is large, the charging period of the capacitor C ₅ is short, i.e., the driving frequency is high, the current I ₃ is small period T _H, longer charging period of the capacitor C _5, i.e., the driving frequency decreases. As described above, the driving frequencies of the switching elements Q ₁ and Q ₂ are set to two values according to the magnitude of the current I ₃ , and during the period T _H in which the voltage V ₁ ′ is larger than the voltage V ₇ ,
Since the driving frequency is lowered to increase the lamp current I _La, and during the period _TL in which the voltage V ₁ ′ is smaller than the voltage V ₇ , the driving frequency is increased to decrease the lamp current I _La , The ripple component of the lamp current I _La can be reduced at the peak and the valley of the voltage V ₁ , and the crest factor can be improved.

[0109] In this embodiment, by adjusting the voltage V ₇ which is a threshold value of the comparator CP _1, the driving frequency of the switching elements Q _1, Q ₂ periods of low T _H,
The period _TL during which the drive frequency is high can be adjusted.
Further, to set the drive frequency in the period T _H by the current I ₂ of the fundamental frequency setting circuit 5a, since the current I ₁ of transistor Q _6, which is determined by the resistor R ₁₁ can set the drive frequency in the period T _L , Embodiment 1
Similarly, the crest factor of the lamp current I _La can be improved according to the pulsating voltage V ₁ (the power supply voltage of the AC power supply AC).

The configuration other than the drive frequency control unit 5 is the same as that of the first embodiment, and a description thereof will be omitted. (Embodiment 14) FIG. 3 is a circuit diagram of a power supply device according to this embodiment.
FIG. 37 shows the waveform of each part in FIG. In this embodiment, the limiter portion upper limit setting circuit 4c in the power supply device of Embodiment 1 detects a lamp current I _La that flows through the lamp La in the current transformer CT _1, the limiter portion 4 Works in accordance with the lamp current I _La Threshold values V ₃ and V ₄ , that is, upper limit value V
By setting the _H and the lower limit value V _L, the lamp current I _La is performs an operation for correcting the variation and fluctuates, have improved crest factor of the lamp current I _La.

That is, the limiter unit upper / lower limit setting circuit 4
c is detected the peak value and the effective value of the lamp current I _La, as shown in Table 1, the larger the peak value than the target value of the lamp current I _La, the lower limit V _L of the limiter portion 4 If the effective value of the lamp current I _La is larger than the target value, the upper limit value V _H of the limiter unit 4 is reduced. Thus, the upper limit V of the limiter portion ₄ detects the lamp current I _La
By controlling _H and the lower limit _VL , the lamp current I
The variation of _La can be corrected, and the crest factor can be reduced.

The structure other than the limiter unit 4 is the same as that of the first embodiment.
Therefore, the description is omitted.

[0113]

[Table 1]

(Embodiment 15) FIG. 37 is a circuit diagram of a power supply device according to the present embodiment, and FIG. 38 shows waveforms of respective parts. In this power supply device, the detection unit 3 is different from the power supply device of the first embodiment.
There dividing the pulsating voltage V ₁ of the full-wave rectifier DB by resistors R _1, R _2, programmer glue supply unit 8 generates a detection voltages V ₁ 'on the basis of the partial pressure value. The limiter portion 4, and outputs the voltage V ₂ obtained by waveform shaping the detection voltage V ₁ 'at the upper limit value V _H and the lower limit value V _L. Then, the drive frequency control unit 5 determines the drive frequency of the switching elements Q ₁ and Q ₂ based on the voltage V ₂ .

Here, as shown in FIG. 38, the programmable power supply unit 8 supplies a voltage V in consideration of the load characteristic of the lamp La.
Outputs ₁ '. That is, the programmable power supply unit 8 detects that the divided voltage value of the resistors R ₁ and R ₂ becomes 0 V, and synchronizes the pulsating voltage V ₁ with the detection signal V ₁ ′ output to the limiter unit 4. The operation of the control circuit 2 downstream of the limiter unit 4 is the same as that of the first embodiment, and a description thereof will be omitted.

As described above, since the programmable power supply unit 8 outputs the detection voltage V ₁ ′ in consideration of the load characteristics in advance, the drive frequency of the switching elements Q ₁ and Q ₂ can be corrected, and the lamp current I _La Can be improved. (Embodiment 16) FIG. 3 is a circuit diagram of a power supply device of this embodiment.
9 shows a waveform diagram of each part in FIG.

In the present embodiment, in the power supply device of the first embodiment, the lamp current detecting circuit 9 detects the lamp current I _La by using the current detecting means 9a connected to one filament of the lamp La. When the current detection circuit 9 detects a sudden increase in the lamp current I _La , the drive frequency of the switching elements Q ₁ and Q ₂ is temporarily increased to prevent runaway of the lamp current I _La .

The lamp current detection circuit 9 has a lamp current I
Limit I _max of _La is set in advance. For example, FIG.
As shown by 0, when the lamp current I _La suddenly increases due to malfunction of the control circuit 2 and exceeds the upper limit I _max , the lamp current detection circuit 9 determines that the lamp current I _La has exceeded the upper limit I _max. detects and outputs a predetermined period T _a by current Ia to the timer unit 6.

In the timer section 6, the lamp current detection circuit 9
, The current flowing through the transistor Q ₈ increases to (I ₃ + Ia).
_5, the charging current is increased, and the charging period is shortened. Accordingly, in the period T _a, the switching elements Q _1, Q
The driving frequency of _{No. 2} is temporarily set to a high value f1, and the lamp current I _La flowing through the lamp _La decreases. After the predetermined time period T _a has elapsed, the lamp current detection circuit 9 to stop the flow the current Ia to the timer section 6, the switching elements Q _1, Q ₂ of the driving frequency f of the normal operation of the driving frequency
By returning to _L , the lamp can be lit normally.

[0120] Incidentally, the period T _a lamp current detecting circuit 9 is flow a current Ia to the timer unit 6, the lamp current I _La is decreased at the upper limit value I _max and the driving frequency f ₁ and the period T _a of the lamp current I _La From the degree, the time until the lamp current I _La decreases to the value at the time of normal lighting may be roughly estimated, and the value may be set. Alternatively, it is acceptable to set the lower limit value of the lamp current I _La, the lamp current when the I _La is reduced to a predetermined lower limit value, the lamp current detecting circuit 9 is a current Ia to the timer section 6
May be stopped. Further, the current Ia flowing from the lamp current detection circuit 9 to the timer section 6 may be gradually reduced with the passage of time to smoothly return to the normal control.

The configuration other than the lamp current detection circuit 9 is the same as that of the first embodiment, and a description thereof will be omitted. (Embodiment 17) FIG. 4 is a circuit diagram of a power supply device according to this embodiment.
FIG. 42 shows a waveform diagram of each part. In this embodiment,
In the power supply device of the first embodiment, when the lamp current detection circuit 9 detects that the lamp current I _La decreases below a predetermined value, the drive frequency of the switching elements Q ₁ and Q ₂ of the inverter circuit 1 is reduced for a certain period. By increasing the lamp current I _La , the extinguishing of the lamp La is prevented.

In the lamp current detection circuit 9, the lower limit value I _min of the lamp current I _La is set in advance.
When the lamp current I _La gradually decreases and reaches the lower limit value I _min as shown in FIG. 7, the lamp current detection circuit 9 detects that the lamp current I _La has dropped to the lower limit value I _min , and a predetermined period T _b , The transistor Q of the drive frequency control unit 5
_The current Ib is output to ₁₈ .

The transistors Q ₁₇ and Q ₁₈ constitute a current mirror circuit. When a current flows through the transistor Q ₁₈ , a part of the current (= Ib) flowing from the drive frequency control unit 5 to the timer unit 6 is reduced by the transistor Q _18. flow _17, the current flowing through the transistor Q ₈ becomes (I ₃ -Ib). Thus, the current flowing through the transistor Q ₈ is reduced by the current Ib than normal, the charging time of the capacitor C ₅ is increased, the driving frequency of the switching elements Q _1, Q ₂ decreases from f _L to f ₂ ( f _L > f ₂ ). During this time, the lamp current I _La flowing through the lamp _La temporarily increases,
The lamp current I _La increases. Then, after a predetermined time period T _b, lamp current detection circuit 9 to stop the flow the current Ib to the driving frequency control unit 5, by returning to the normal control, it is possible to light the lamp La normally.

Incidentally, the lower limit value I _min of the lamp current I _La
When a drive frequency f ₂ after the detection, the degree to which the lamp current I _La increases, the lamp current I _La is approximate the time to reach the value of the normal lighting, may be the value as a predetermined time period T _b . Also, an upper limit value of the lamp current I _La is set,
When the lamp current I _La has increased to a predetermined upper limit, the lamp current detection circuit 9 may stop flowing the current Ib. Further, the control may be smoothly returned to the normal control by gradually decreasing the current Ib with the passage of time.

The configuration other than the lamp current detection circuit 9 is the same as that of the first embodiment, and a description thereof will be omitted. (Embodiment 18) In this embodiment, for example, Embodiment 16
Or the lamp current I _La having the maximum point of the envelope at the peak of the pulsating voltage V ₁ as in the power supply device of FIG.
Is obtained, the crest factor of the lamp current I _La is improved.

FIG. 43 shows a waveform of such a power supply device. As described above, assuming that the lower limit f _L of the driving frequency modulation of the switching elements Q ₁ and Q ₂ is substantially constant, the pulsating voltage V ₁
The lamp current I _La further increases at the peak of, and the crest factor deteriorates. Therefore, in the vicinity of the valley pulsating voltage V _1, the control circuit 2 clamps the driving frequency f to the upper limit value f _H, suppressing an increase in the lamp current I _La. Next, the control circuit 2 increases the lamp current I _La by gradually lowering the drive frequency f from the upper limit value f _H. When the drive frequency f reaches the lower limit value f _L , the control circuit 2
Increases the driving frequency f again, and reduces the lamp current I _La near the peak of the pulsating voltage V ₁ . Further, the pulsating voltage V
_When the peak exceeds ₁ , the control circuit 2 gradually lowers the drive frequency f. When the drive frequency f reaches the lower limit value f _L , the control circuit 2 gradually increases the drive frequency f again. clamps the driving frequency f at the upper limit value f _H.
Thereafter, the control circuit 2 in synchronization with the pulsating voltage V ₁ was the above-described operation is repeated.

As described above, in the present embodiment, the pulsating voltage V
_When the envelope of the lamp current I _La between the valley and the peak of ₁ is minimized, the driving frequency f of the switching elements Q ₁ and Q ₂ is made the lowest and the lamp current I _La is increased.
When the envelope of the lamp current I _La becomes maximum, the driving frequency f is increased to decrease the lamp current I _La ,
By correcting the lamp current I _La , a substantially constant current I _La ′ can be obtained, and the crest factor of the current I _La ′ can be improved. In (Embodiment 19) In this embodiment, a power supply device of embodiment 10, the crests of the pulsating voltage V _1, the lamp L
The lamp current I _La flowing through a is detected, and feedback control is performed using the absolute value.

In general, the lamp current I _La of the lamp La fluctuates due to the fluctuation of the pulsating voltage V _{1 and} the fluctuation of the ambient temperature of the lamp La. When lit the discharge lamp load circuit configuration of the embodiment 9, as shown in FIG. 44 (a) ~ (c) , in particular a lamp current I in the mountain portion of the pulsating voltages V _1
La fluctuates greatly. For example, when the lamp current I _La is increased, as shown in FIG. 44 (b), an increase primarily in the mountains of the pulsating voltage V _1, even when the lamp current I _La decreases, Fig 44 (c) as shown in, primarily pulsating voltages V ₁
There is a tendency to decrease in the mountains.

Therefore, in the present embodiment, the pulsating voltage V
Detecting a lamp current I _La in _one peak portion, when the lamp current I _La is large, reducing the lamp current I _La by increasing the driving frequency f of the switching element Q _1, Q _2, the lamp current I _La is If smaller, the switching elements Q ₁ , Q ₂
Is lowered to increase the lamp current I _La . As described above, since the fluctuation of the lamp current I _La at the peak of the pulsating voltage V _{1 which} is easily detected as compared with the power supply voltage is detected and the lamp current I _La is controlled to be substantially constant, The lamp La can be stably turned on.

Since the circuit configuration is the same as that of the tenth embodiment, the description is omitted. (Embodiment 20) FIG. 4 is a circuit diagram of a power supply device according to this embodiment.
FIG. 5 shows a waveform diagram of each part in FIG. In this embodiment,
In the power supply device according to the first embodiment, the lamp current detection circuit 9
Is connected in series with a lamp La composed of a discharge lamp, and a thinning control unit 10 is provided between the timer unit 6 and the driver unit 7 of the control circuit 2. The thinning control unit 10 outputs the output voltage V _{6 of the} timer unit _6. and it outputs an output signal V ₈ to the driver section 7 based on.

As shown in FIGS. 46A and 46B, at time t
In _1, the lamp current I when _La flows exceeds a predetermined threshold value I _m to the lamp La, the output V ₉ of the lamp current detecting circuit 9 is turned on. When the output V ₉ is turned on, the thinning control unit 10 outputs an output signal V ₈ obtained by thinning an output signal V ₆ of the timer unit 6 at a predetermined ratio to the driver unit 7, an intermittent switching elements Q _1, Q ₂ And the fluctuation of the lamp current I _La can be suppressed.

At time t ₂ , the lamp current I
When _La is smaller than the threshold value I _m, the output V ₉ of the lamp current detecting circuit 9 is turned off, thinning control unit 10 outputs an output signal V ₆ of the timer unit 6 as it is, the output signal of the timer section 6 the switching element Q ₁ by V _6,
To drive the Q _2. As described above, the lamp current I _La is fed back to the control circuit 2 so that the switching elements Q ₁ ,
By controlling thinning a drive signal of Q _2, the discharge lamp makes it possible to stable lighting. (Embodiment 21) FIG. 4 is a circuit diagram of a power supply device according to this embodiment.
FIG.

As in the power supply of the tenth embodiment, this power supply has a first resonance system including an inductor L ₁ and a capacitor C ₂ and a _second resonance system including an inductor L ₂ and a capacitor C _8. One of have a resonance system, by clamping the voltage across or the ground level of the capacitor C ₁ the voltage across the capacitor C ₂ by the diode D _9, D _10, the voltage across V _DC of the capacitor C ₁ is abnormally boost And the breakdown voltage of each element can be set low.

[0134] In this circuit, according to the amplitude of the voltage across the capacitor C _2, even if momentary input voltage is lower than the voltage V _DC is generated, it is possible to take the input current from the capacitor C _4, In order to supply high-frequency power to the load 11 composed of a discharge lamp or the like, simultaneously correct input current distortion, and further improve the crest factor of the load current waveform, the driving frequency of the switching elements Q ₁ and Q ₂ must be changed. It is necessary to modulate according to the input voltage.

In general, when a power supply device is commercialized, it is necessary to correct the variation of the used components or to adjust the output, for example, before shipping because the used components have variations. In this power supply device as well, in addition to the above-described functions, it is necessary to correct the variation of the used components and adjust the output.
For example, when performing only the frequency modulation of the driving frequencies of the switching elements Q ₁ and Q ₂ , the adjustment range is expected to be narrower than when only the output adjustment is performed by the frequency modulation.

[0136] Here, the maximum output by adjusting the on-duty of the switching elements Q _1, Q _2, can also vary the output, 50% on time of the switching elements Q _1, Q ₂ are equal And even if the on time of either of the switching elements Q ₁ and Q ₂ is long,
The output decreases. In the present embodiment, the output adjustment is performed by frequency modulation, and the variation of the components is corrected by the on-duty modulation of the switching elements Q ₁ and Q ₂ , so that the variation of the components can be reduced without narrowing the output adjustment range. Can be corrected. Here, the output may increase or decrease in some cases due to the variation of the components. Therefore, at the time of design, it is turned on between 100% and 50% or between 50% and 0%. What is necessary is just to determine the center of duty and design.

[0137] Figure 48 shows the relationship between the switching elements Q _1, Q ₂ of the drive frequency f and the on-duty switching element Q _1. Here, when there is no variation in components and the design is as designed, the center of the operation is set to e in FIG.
If g is set, control can be performed with the same on-duty in any of the operation modes of preheating, starting, full lighting, and dimming lighting.

For example, when the components are evenly distributed so that the output becomes lowest in each operation mode, the on-duty is reduced to 50% as shown in FIG. 48A in order to increase the output in each operation mode. By performing the adjustment, the output can be controlled while correcting the variation of the components. In each of the operation modes, when it is necessary to correct the variation of the parts, see FIG.
As shown in (1), by setting the on-duty to a desired value in each operation mode, it is possible to absorb component variations. Further, as shown in FIG. 48C, the on-duty may be set so that the on-duty changes linearly in each operation mode.
As shown in (1), the on-duty may be set in both the 0 to 50% region and the 50 to 100% region for each operation mode, and the variation of parts can be similarly corrected.

As described above, the frequency modulation is performed to adjust the load output and to improve the crest factor of the load current, and the adjustment of the component variation is corrected by adjusting the on-duty, so that a simple configuration can be realized. Each of the above functions can be realized by the control circuit. The power supply device (Embodiment 22) In this embodiment, as shown in FIG. 49, the inverter circuit 1 is mainly a main inverter 1a for supplying the lamp current I _La, and mainly the filament inverter b for supplying a filament current I _f The inverter circuits 1a and 1b share the switching elements Q ₁ and Q ₂ and constitute separate resonance systems.

The main inverter 1a is the same as the inverter circuit 1 of the first embodiment, and a description thereof will be omitted. On the other hand, the filament inverter 1b includes a switching element Q _1, Q _2, is a capacitor C ₁₀ and trans T ₁ which is connected across the series circuit composed of switching elements Q _1, Q _2, 2 of the transformer T ₁ The filament current _If is supplied to both filaments of the lamp La from the next side. The filament inverter 1b includes a capacitor C
₁₀ and has a frequency characteristic of the resonant circuit composed of the primary winding of the transformer T _1, shows a frequency characteristic as the filament current I _f increases around higher preheat frequency than lamp operating frequency .

As described above, by setting the frequency characteristics of the main inverter 1a and the filament inverter 1b individually, the filament current _If is sufficiently secured at the time of preliminary preheating, and the filament current _If is reduced at the time of lighting to reduce the lamp current. The lamp life of La can be extended.
By the way, in recent years, fluorescent lamps have tended to be reduced in diameter in order to reduce the size of lighting equipment, increase the efficiency of lamps, and save resources. The lamp impedance per unit length excluding the base of this type of lamp is the same type of lamp (for example, FL20).
S and FL20SS / 18) tend to be larger as the pipe diameter becomes smaller. In particular, T with a tube diameter of 16 mm
T such as 5-14, T5-21, T5-28, T5-35, etc.
5 lamps (or 'TL'5: a product name of Philips) have a lamp impedance per unit length of 8 Ω / cm or more excluding the base and a tube diameter of 28 mm.
~ 32.5 mm lamp (for example, FL20S, FL2
0SS / 18, FL30S, FL40S / 38, FL4
0SS / 37 etc.) or a 25.5 mm high frequency lighting lamp (eg, FHF16, FHF16-23, FH
F32, FHF32-45, etc.) have a larger lamp impedance than conventional lamps.

However, in a lamp having a small tube diameter such as a T5 lamp and a thin filament, there is a problem that if the filament current _If is passed too much during operation, the lamp life is greatly shortened. In the power supply device of the present embodiment, the filament current _If during lighting can be reduced, so that the lamp life can be extended even when a T5 lamp is used as the lamp La. Embodiments 1 and 2
Needless to say, the T5 lamp may be applied to the lamp La in the one power supply device.

FIG. 50 shows the waveform of each part of the power supply device. The control circuit 2 has a configuration similar to that of the control circuit 2 of Embodiment 1, performs the same operation as that of the embodiment 1 in order to improve the crest factor of the lamp current I _La. The control circuit 2 modulates the drive frequency f of the switching elements Q ₁ and Q ₂ according to the voltage V _{2 obtained} by shaping the detected voltage of the pulsating voltage V ₁ with the upper limit value V _H or the lower limit value _VL . Here, since the filament inverter 1b has a frequency characteristic different from that of the main inverter 1a, the filament current _If flowing to both filaments of the lamp La by the filament inverter 1b greatly changes due to the modulation of the driving frequency f. In particular, when the driving frequency f of the switching elements Q ₁ and Q ₂ is high in the valley of the pulsating current V ₁ , the filament current _If increases. Generally, when the filament current _If during the operation of the lamp La increases, the temperature of the filament increases, and the lamp life is shortened. Therefore, in the present embodiment, the upper limit value V _H of the drive frequency of the switching elements Q ₁ and Q ₂ is set so that the effective value of the filament current _If becomes less than or equal to the predetermined value during the lighting of the lamp La.

Since the configuration other than the inverter circuit 1 is the same as that of the first embodiment, the description thereof is omitted. In the present embodiment, the main inverter 1a and the filament inverter 1b are provided in the power supply device of the first embodiment. However, the present embodiment may be applied to any one of the power supply devices of the first to twenty-first embodiments. Needless to say. (Embodiment 23) In the present embodiment, in the power supply device of Embodiment 10, the inverter circuit 1 is provided with the main inverter 1a and the filament inverter 1b, and the inverter circuit 1 is provided with the lamps La ₁ and La ₂ composed of discharge lamps. They are connected in parallel.

When the lamps La ₁ and La ₂ are turned on in parallel, even if one of the _two lamps La ₁ and La ₂ is removed, control is performed so that the remaining one lamp maintains the lighting state. In this case, a lower limit value of a limiter unit (not shown) constituting the control circuit 2 is set so as to lower the voltage between both ends of the lamp terminal on the removed side. In particular, in the case of general home lighting equipment, when replacing one of the two lamps, if one of the two lamps is removed and the remaining one is turned off, the room becomes darker and replacement work becomes easier. Can not be done. Therefore, even if one of the two lamps is removed, it is necessary to maintain the lighting state of the remaining one lamp.

In this power supply device, the lamp L is controlled by the filament inverter 1b without using the capacitor preheating method.
and a _1, La ₂ filaments flowing filament current, since the preheating of the filaments, to the resonant circuit of the main inverter 1a consisting of an inductance L ₂ and capacitor C ₈ is present, the lamp La ₁ across The voltage V _La1 increases.

When the control circuit 2 controls the driving of the switching elements Q ₁ and Q ₂ at a constant driving frequency without modulating the driving frequency in accordance with the fluctuation of the pulsating voltage V ₁ , as shown in FIG. Although a no-load secondary voltage having a shape substantially similar to the pulsating voltage V ₁ is obtained, the voltage V _La1 across the lamp La ₁ increases in the valley of the pulsating voltage V ₁ because the load is light. In this embodiment, in the valleys of the pulsating voltage V _1, so as to suppress an increase in the high to the no-load secondary voltage driving frequency of the switching elements Q _1, Q _2, 2-lamp during lighting (usually Since the lower limit of the limiter is set lower when one lamp is removed compared to when the lamp is lit, even if one of the lamps La ₁ or La ₂ is removed, the inverter output on the removed side is reduced. can do.

As described above, the rise of the no-load secondary voltage can be reduced by setting the lower limit of the limiter portion lower when one lamp is removed than when two lamps are turned on. Note that the configuration other than the inverter circuit 1 is the same as that of the first embodiment, and a description thereof will be omitted.

[0149]

As described above, the first aspect of the present invention includes a rectifier circuit for full-wave rectifying an AC power supply, a smoothing capacitor for smoothing the output of the rectifier circuit, and a switching element for switching the output of the smoothing capacitor. The switching element includes an inverter circuit that converts the output of the smoothing capacitor to a high frequency and supplies the load to a load, a detection unit that detects the output of the rectifier circuit, and a limiter unit that sets an upper limit value and a lower limit value of the detection value of the detection unit. And a control circuit for supplying a drive signal.In the vicinity of the peak value of the power supply voltage of the AC power supply, the absolute value of the high-frequency current supplied to the load decreases. The load current has a low-frequency ripple that increases the absolute value of the supplied high-frequency current, and the control circuit converts the frequency of the output of the limiter unit to a switch. The drive signal frequency is controlled between the minimum and maximum frequencies corresponding to the upper and lower limits, respectively, so as to generate the drive signal of the switching element and reduce the low frequency ripple generated in the load current. According to the second aspect of the present invention, since the absolute value of the difference between the upper limit value and the lower limit value is increased to reduce the output of the inverter circuit, the drive frequency of the switching element is controlled according to the voltage waveform of the AC power supply. This has the effect of reducing the ripple of the load current at the peaks and valleys of the voltage waveform and improving the crest factor.

According to a third aspect of the present invention, when the effective value of the power supply voltage of the AC power supply increases, the absolute value of the difference between the upper and lower limits increases, and when the effective value of the power supply voltage of the AC power supply decreases, the upper limit increases. In the invention according to claim 4, when the effective value of the power supply voltage of the AC power supply increases, the period during which the frequency of the drive signal is clamped at the maximum frequency is increased. When the effective value of the power supply voltage of the AC power supply decreases, the period during which the frequency of the drive signal is clamped at the minimum frequency is lengthened, so that the output of the inverter circuit remains substantially constant even if the power supply voltage of the AC power supply fluctuates. There is an effect that it can be held.

According to a fifth aspect of the present invention, in accordance with the present invention, the control circuit changes the drive signal between the maximum on-duty and the minimum on-duty determined respectively by the upper limit value and the lower limit value of the limiter unit according to the output of the limiter unit. The on-duty is controlled, and the control circuit controls the frequency of the drive signal between the minimum frequency and the maximum frequency corresponding to the upper limit value and the lower limit value in accordance with the output of the limiter unit. Control, and the on-duty of the drive signal is controlled between the maximum on-duty and the minimum on-duty determined by the upper and lower limits, respectively. Signal on-duty can be controlled, load current ripple can be reduced at peaks and valleys of the voltage waveform, and crest factor can be improved. There is an effect that.

According to a seventh aspect of the present invention, the on-duty of the drive signal of the switching element is clamped to the maximum on-duty for a certain period of time, and the on-duty of the drive signal of the switching element is set to the minimum on-duty. Clamped for a certain period of time,
To reduce the low frequency ripple that occurs in the load current,
The invention according to claim 5, wherein the control circuit controls the absolute value of the difference between the upper limit value and the lower limit value of the limiter unit to control the absolute value of the difference between the maximum on-duty and the minimum on-duty of the drive signal. Similarly, the on-duty of the drive signal of the inverter circuit can be controlled according to the voltage waveform of the AC power supply, and the ripple of the load current can be reduced at the peaks and valleys of the voltage waveform, and the crest factor can be improved. There is.

According to a tenth aspect of the present invention, the output of the limiter is clamped to the upper limit in a range where the detection value of the detector exceeds the upper limit, and the limiter is output in a range where the detection value of the detector is lower than the lower limit. Outputs a voltage proportional to the waveform of the detected value, so that the drive frequency of the switching element can be controlled in accordance with the voltage waveform of the AC power supply, reducing the ripple of the load current at the peaks and valleys of the voltage waveform, There is an effect that the crest factor can be improved.

According to the eleventh aspect, the voltage across the smoothing capacitor is detected, and when the voltage across the smoothing capacitor is low, the control circuit increases the output of the inverter circuit. In some cases, the output of the inverter circuit can be kept substantially constant. According to a twelfth aspect of the present invention, the load current flowing to the load is detected, and the upper limit and the lower limit of the limiter are adjusted so as to reduce low frequency ripple included in the load current. There is an effect that it can be improved.

According to the thirteenth aspect, the minimum frequency is set to a value higher than the resonance frequency of the inverter circuit, so that there is an effect that the loss of the switching element can be reduced. According to a fourteenth aspect of the present invention, the on-duty of the drive signal is adjusted so as to correct the variation of components,
Since the frequency of the drive signal is controlled to improve the load output, input current distortion and the crest factor of the load current,
There is an effect that the crest factor can be improved and the output variation due to the component variation can be corrected.

According to a fifteenth aspect of the present invention, a load current detecting circuit for detecting a load current, and when a detected value of the load current detecting circuit exceeds a predetermined reference value, a drive signal for the switching element is thinned out to intermittently switch the switching element. Since the thinning-out control circuit for driving the load is provided, the crest factor of the load current can be improved as in the twelfth aspect.

According to a sixteenth aspect of the present invention, the output of the limiter section is a binary value consisting of only an upper limit value and a lower limit value. The frequency can be controlled. Claim 1
In the invention of the seventh aspect, the crest factor is improved by detecting the current flowing to the load at the peak of the output of the rectifier circuit and controlling the output of the inverter circuit by suppressing the fluctuation of the current. can do.

According to the eighteenth aspect of the present invention, since the control circuit drives the switching element using a preset drive signal in synchronization with the voltage waveform of the AC power supply, the control circuit can respond to the voltage waveform with a simple configuration. In addition, it is possible to modulate the drive signal of the switching element, reduce the ripple of the load current at the peak and the valley of the voltage waveform, and improve the crest factor.

According to a nineteenth aspect of the present invention, the load comprises a discharge lamp. In the twentieth aspect of the present invention, the control circuit controls the output of the inverter circuit according to the load current flowing through the discharge lamp. This has the effect of improving the crest factor of the current and eliminating flickering of the discharge lamp. According to a twenty-first aspect of the present invention, in the power supply device including a plurality of sets of a discharge lamp and an inverter circuit, the plurality of inverter circuits share a switching element, and the resonance circuit of the inverter circuit is connected in parallel. Even if the discharge lamp is removed, the control circuit turns on the remaining discharge lamps and suppresses the upper limit of the limiter so that the voltage between the outputs of the inverter circuit to which the removed discharge lamp was connected is reduced. As a result, the output of the inverter circuit from which the discharge lamp has been removed can be reduced, another lamp can be turned on even when the lamp is replaced, and the lamp can be replaced safely.

According to a twenty-second aspect of the present invention, when the load is such that the lamp impedance per unit length of the lamp excluding the base is approximately 8
Since it is composed of fluorescent lamps of Ω / cm or more,
There is an effect that a lamp can be used. According to a twenty-third aspect of the present invention, the inverter circuit has a first resonance system including a capacitor and an inductor, and a part of the high-frequency power of the inverter circuit is provided between a connection point of the rectification circuit and the smoothing capacitor and one end of the resonance system. An impedance element for feedback is connected, and the impedance element is connected to the inductor and the second
Since the above-described resonance system is configured, it is possible to further reduce the ripple component of the load current and reduce the crest factor by reducing the harmonic component of the input power.

[Brief description of the drawings]

FIG. 1 is a circuit diagram illustrating a power supply device according to a first embodiment.

FIG. 2 is a waveform chart showing the operation of each unit of the above.

FIGS. 3A and 3B show the operation of each of the above-described parts, in which FIG. 3A is a waveform diagram at the time of full lighting and FIG. 3B is a waveform diagram at the time of dimming lighting.

4A and 4B show the operation of each section of the above, wherein FIG. 4A is a waveform diagram at the time of full lighting, and FIG. 4B is a waveform diagram at the time of dimming lighting.

FIG. 5 is a circuit diagram illustrating a power supply device according to a second embodiment.

FIG. 6 is a waveform chart showing the operation of each unit of the above.

FIG. 7 is a waveform diagram when the gain is increased.

FIG. 8 is a waveform chart in a case where upper and lower limits of the limiter unit are changed.

FIG. 9 is a waveform diagram when only the lower limit of the limiter unit operates.

FIG. 10 is a waveform chart when only the upper limit of the limiter unit operates.

FIG. 11 is a circuit diagram illustrating a power supply device according to a third embodiment.

FIG. 12 is a waveform diagram of each part when the on-duty is modulated in an area of 50% or less.

FIG. 13 is a waveform chart of each part when the on-duty is modulated in a region of 50% or more.

FIG. 14 is a circuit diagram showing a power supply device according to a fourth embodiment.

FIG. 15 is a diagram showing a relationship between a driving frequency of the inverter circuit and a lamp current.

FIG. 16 is a waveform chart showing the operation of each unit of the above.

FIG. 17 is another waveform chart showing the operation of each unit of the above.

FIG. 18 is a waveform chart showing the operation of each part of the power supply device according to the fifth embodiment.

FIG. 19 is another waveform chart showing the operation of each unit of the above.

FIG. 20 is another waveform chart showing the operation of each unit of the above.

FIG. 21 is still another waveform chart showing the operation of each unit of the above.

FIGS. 22A and 22B are waveform diagrams illustrating the operation of the power supply device according to the first embodiment.

FIGS. 23A and 23B are waveform diagrams illustrating the operation of the power supply device according to the sixth embodiment.

FIG. 24 is a circuit diagram showing a power supply device according to a seventh embodiment.

FIGS. 25A and 25B are waveform diagrams illustrating the operation of the power supply device according to the first embodiment.

FIGS. 26A and 26B are waveform diagrams illustrating the operation of the power supply device according to the seventh embodiment.

FIGS. 27 (a) and 27 (b) are other waveform diagrams for explaining the operation of the above power supply device.

FIG. 28 is a circuit diagram showing a power supply device according to an eighth embodiment.

FIG. 29 is a circuit diagram showing a power supply device according to a ninth embodiment.

FIG. 30 is a circuit diagram showing a power supply device according to a tenth embodiment.

FIGS. 31 (a) and 31 (b) are waveform diagrams for explaining the above operation.

FIG. 32 is a circuit diagram showing a power supply device according to an eleventh embodiment.

FIG. 33 is a circuit diagram showing a power supply device according to a twelfth embodiment.

FIG. 34 is a circuit diagram showing a power supply device according to a thirteenth embodiment.

FIG. 35 is a waveform chart showing the operation of each unit of the above.

FIG. 36 is a circuit diagram showing a power supply device according to a fourteenth embodiment.

FIG. 37 is a circuit diagram showing a power supply device according to Embodiment 15.

FIG. 38 is a waveform chart showing the operation of each unit of the above.

FIG. 39 is a circuit diagram showing a power supply device according to a sixteenth embodiment.

FIG. 40 is a waveform chart showing the operation of each unit of the above.

FIG. 41 is a circuit diagram showing a power supply device according to a seventeenth embodiment.

FIG. 42 is a waveform chart showing the operation of each unit of the above.

FIG. 43 is a waveform chart showing the operation of each part of the power supply device according to the eighteenth embodiment.

FIGS. 44 (a) to (c) are waveform diagrams showing the operation of each part of the power supply device according to the nineteenth embodiment.

FIG. 45 is a circuit diagram showing a power supply device according to a twentieth embodiment.

FIG. 46A is a waveform diagram showing the operation of each unit of the power supply device of the above, and FIG. 46B is a waveform diagram with an enlarged time axis.

FIG. 47 is a circuit diagram showing a power supply device according to a twenty-first embodiment.

FIG. 48 is a diagram illustrating a relationship between a drive frequency and an on-duty in each operation mode of the above.

FIG. 49 is a circuit diagram showing a power supply device according to a twenty-second embodiment.

FIG. 50 is a waveform chart showing the operation of each unit of the above.

FIG. 51 is a circuit diagram showing a power supply device according to Embodiment 23.

FIG. 52 is a circuit diagram showing a conventional power supply device.

FIG. 53 is a circuit diagram showing another power supply device of the above power supply system;

FIG. 54 is a circuit diagram showing another power supply device of the above power supply device;

FIG. 55 is a circuit diagram showing still another power supply device according to the above.

FIG. 56 is a diagram for explaining a relationship between a driving frequency and an output according to the embodiment.

FIG. 57 is a circuit diagram showing still another power supply device of the above.

FIGS. 58 (a) and (b) are waveform diagrams showing waveforms of respective parts of the above.

[Explanation of symbols]

First inverter circuit 2 control circuit 3 detecting circuit 4 limiter unit AC AC power DB rectifying circuit F ₁ input filter V ₂ voltage V ₃ lower limit V ₄ upper limit Q _1, Q ₂ switching elements

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor: Masahiro Naroo 1048, Kazuma Kadoma, Kadoma, Osaka Prefecture Inside the Matsushita Electric Works Co., Ltd. Inside

Claims (23)

[Claims] 1. A rectifying circuit for full-wave rectifying an AC power supply, a smoothing capacitor for smoothing an output of the rectifying circuit, a switching element for switching an output of the smoothing capacitor, and converting an output of the smoothing capacitor to a high frequency. An inverter circuit for supplying an output to the load, a detection unit for detecting an output of the rectifier circuit, and a limiter unit for setting an upper limit value and a lower limit value of a detection value of the detection unit, and supplying a drive signal to the switching element. The absolute value of the high-frequency current supplied to the load decreases near the peak value of the power supply voltage of the AC power supply, and is supplied to the load near the zero crossing of the power supply voltage of the AC power supply. The load current has low frequency ripple such that the absolute value of the high frequency current increases, and the control circuit The frequency of the drive signal is converted to a minimum frequency corresponding to the upper limit value and the lower limit value, respectively, so as to generate a drive signal for the switching element by frequency conversion, and reduce a low frequency ripple generated in the load current. And a maximum frequency. 2. The power supply device according to claim 1, wherein the output of the inverter circuit is reduced by increasing the absolute value of the difference between the upper limit value and the lower limit value. 3. When the effective value of the power supply voltage of the AC power supply increases, the absolute value of the difference between the upper limit value and the lower limit value increases, and when the effective value of the power supply voltage of the AC power supply decreases, the upper limit value and the upper limit value increase. The power supply device according to claim 1, wherein an absolute value of the difference between the lower limit values is reduced. 4. When the effective value of the power supply voltage of the AC power supply increases, the period during which the frequency of the drive signal is clamped at the maximum frequency increases, and when the effective value of the power supply voltage of the AC power supply decreases, the drive voltage decreases. 2. The power supply device according to claim 1, wherein a period during which the frequency of the signal is clamped at the minimum frequency is lengthened. 5. The control signal according to an output of the limiter unit, wherein the drive signal is set between a maximum on-duty and a minimum on-duty respectively determined by the upper limit value and the lower limit value of the limiter unit. 5. The power supply device according to claim 1, wherein the on-duty of the power supply is controlled. 6. The control circuit controls a frequency of a drive signal between a minimum frequency and a maximum frequency corresponding to the upper limit value and the lower limit value, respectively, in accordance with an output of the limiter unit. The power supply device according to claim 1, wherein the on-duty of the drive signal is controlled between a maximum on-duty and a minimum on-duty determined respectively by a value and the lower limit. 7. The power supply device according to claim 5, wherein an on-duty of the drive signal of the switching element is clamped at the maximum on-duty for a certain period. 8. The power supply device according to claim 5, wherein the on-duty of the drive signal of the switching element is clamped at the minimum on-duty for a certain period. 9. The control circuit controls an absolute value of a difference between the upper limit value and the lower limit value of the limiter unit so as to reduce the low frequency ripple generated in the load current. 9. The power supply device according to claim 5, wherein an absolute value of a difference between the maximum on-duty and the minimum on-duty is controlled. 10. The output of the limiter is clamped to the upper limit in a range where the detection value of the detector exceeds the upper limit, and the output of the limiter is clamped to the upper limit in a range where the detection value is lower than the lower limit. 10. The power supply device according to claim 1, wherein the limiter outputs a voltage proportional to the waveform of the detected value. 11. The power supply according to claim 1, wherein a voltage across the smoothing capacitor is detected, and when the voltage across the smoothing capacitor is low, the control circuit increases the output of the inverter circuit. apparatus. 12. The method according to claim 11, wherein the load current flowing through the load is detected, and the upper limit value and the lower limit value of the limiter are adjusted so as to reduce a low frequency ripple included in the load current. The power supply device according to claim 1. 13. The power supply device according to claim 1, wherein said minimum frequency is set to a value higher than a resonance frequency of said inverter circuit. 14. An on-duty adjustment of the drive signal so as to correct a variation in parts, and a frequency of the drive signal is controlled so as to improve a load output, an input current distortion and a crest factor of a load current. The power supply device according to claim 1, wherein: 15. A load current detection circuit for detecting the load current, and when a detection value of the load current detection circuit exceeds a predetermined reference value, a drive signal for the switching element is thinned out to intermittently switch the switching element. 10. A power supply device according to claim 1, further comprising a thinning control circuit for driving the power supply. 16. The apparatus according to claim 1, wherein an output of said limiter section is a binary value consisting of only said upper limit value and said lower limit value.
10. The power supply according to any one of claims 9 to 9. 17. The power supply according to claim 1, wherein the control circuit controls an output of the inverter circuit by detecting a current flowing through the load at a peak of an output of the rectifier circuit. apparatus. 18. The power supply device according to claim 1, wherein the control circuit drives the switching element using a drive signal set in advance in synchronization with a voltage waveform of an AC power supply. 19. The power supply device according to claim 1, wherein said load is a discharge lamp. 20. The power supply device according to claim 19, wherein said control circuit controls an output of said inverter circuit according to a load current flowing through said discharge lamp. 21. A power supply device comprising a plurality of sets of the discharge lamp and the inverter circuit, wherein the plurality of inverter circuits share the switching element, and a resonance circuit of the inverter circuit is connected in parallel.
Even if any of the discharge lamps is removed, the control circuit turns on the remaining discharge lamps and reduces the output voltage of the inverter circuit to which the removed discharge lamps are connected, 21. The power supply device according to claim 19, wherein the upper limit of the limiter unit is suppressed. 22. A power supply unit according to claim 19, wherein said discharge lamp is a fluorescent lamp having a lamp impedance per unit length of about 8 Ω / cm or more excluding a base. 23. The inverter circuit has a first resonance system including a capacitor and an inductor, and a high frequency power of the inverter circuit is provided between a connection point of the rectification circuit and the smoothing capacitor and one end of the resonance system. 23. The power supply device according to claim 1, wherein an impedance element for partially feeding back is connected, and the impedance element forms a second resonance system with the inductor.