JPH05109491A - High-frequency lighting device - Google Patents

Abstract

PURPOSE:To perform a sufficient power source voltage fluctuation compensating action in the full-lighting state and perform smooth dim lighting at the time of dimming under phase control. CONSTITUTION:A power source voltage fluctuation compensating circuit 3 keeping the output to an inverter circuit 4 constant when the power source voltage is fluctuated is provided. A compensation stopping circuit 2 stopping the operation of the power source voltage fluctuation compensating circuit 3 only when a lamp L is dim-lighted is provided. When the phase control width is large, the output width of an inverter gate G, is increased, and the charging voltage VC5 of a capacitor C5 exceeds the Zener voltage VZD2 of a Zener diode ZD2. Voltage is generated across both ends of a resistor R7, a thyristor Q4 is turned on the turn a transistor Q5 on. The anode voltage VR2 of PUT. Q3 of the compensation stopping circuit 2 is fixed on the Zener voltage V2D2, it is not affected by the voltage VC1 of a capacitor C1 proportional to the fluctuation of the power source voltage, and the function of the compensation stopping circuit 2 is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency lighting device for lighting an incandescent lamp including a mini halogen light bulb through a lighting device which performs step-down from a commercial power source, voltage conversion such as frequency, or on / off control. Is.

[0002]

2. Description of the Related Art It is desirable to use a light source whose light distribution can be easily designed in order to perform an appropriate lighting design according to the purpose and application, and a point light source has the greatest degree of freedom in light distribution design. .. As a light source close to the point light source, a low-voltage mini halogen bulb has recently been widely used. The rated voltage of this type of halogen bulb is, for example, 12V,
Since it cannot be directly connected to a commercial power source and turned on, a step-down means is required.

As a step-down means for the commercial power source, a step-down transformer compatible with the frequency of the commercial power source is conceivable. However, since the step-down transformer is relatively large, it is not possible to satisfy the demand for downsizing of lighting equipment. In order to solve such a problem, it has been proposed to light an incandescent light bulb such as a halogen light bulb with high frequency power. Conventionally, in such an inverter circuit that is lit with high-frequency power, for example, a method of detecting the input voltage and controlling the oscillation start phase is used to stabilize the lamp voltage against fluctuations in the power supply voltage. It was

FIG. 5 shows a conventional example in which a rectifier Re composed of a diode bridge is connected to both ends of a commercial power supply AC, and a series circuit of a diode D ₁ and a capacitor C ₁ is connected to both ends of its output terminal, and the capacitor C Resistor R ₁ at both ends of ₁
And the series circuit of R ₂ are connected, and the connection point is PU
The anode of a T (programmable unijunction transistor) Q ₃ is connected, and the cathode of the PUT Q ₃ is connected to the base of the transistor Q ₂ .

At both ends of the rectifier Re, a series circuit of a resistor R ₃ and a capacitor C _2, a series circuit of capacitors C ₃ and C _{4, and} a series circuit of transistors Q ₁ and Q ₂ are connected in parallel, and The connection point between R ₃ and capacitor C ₂ is
It is connected to the gate of the PUT Q ₃ . The connection point between the capacitors C ₃ and C ₄ is connected to the connection point between the transistors Q ₁ and Q ₂ via the primary windings of the step-down transformer T ₁ and the current transformer CT. A lamp L consisting of a halogen bulb is connected to the secondary winding of the step-down transformer T ₁ , and one ends of the secondary and tertiary windings of the current transformer CT are connected to the bases of the transistors Q ₁ and Q _2. There is.

Here, the diode D ₁ , the capacitors C ₁ and C ₂ , the resistors R _{1 to} R ₃ and the PUT · Q ₃ compose the power supply voltage fluctuation compensating circuit 3, and the transistors Q ₁ and Q ₂ ,
The inverter circuit 4 is composed of the capacitors C ₃ and C ₄ . Next, the operation of the circuit will be described with reference to FIG. Rectifier R when the input voltage Vs from the commercial power source AC fluctuates
The output waveform Vs _{1 of} e is shown by a and b, respectively, as shown in FIG. When V _{s (a)} > V _{s (b)} , the charging voltage generated in the capacitor C ₁ is also proportional to V _s , so that the voltage appearing at the resistor R ₂ is also V _{R2 (a) as} shown in FIG. ＞ V _{R2 (b)}
Becomes

On the other hand, the charging voltage curve applied to the capacitor C ₂ is almost the same although there is a slight difference. Therefore, due to the difference in the voltage V _R2 , the phase at which the PUT Q ₃ turns on is the output voltage Vs. _The larger ₁ is, the longer the delay is. Therefore, the output voltage is suppressed, and the fluctuation of the lamp voltage due to the fluctuation of the power supply voltage is absorbed. As a result, the lamp voltage is kept constant regardless of the fluctuation of the power supply voltage. Incidentally, Ha 6 shows a collector-emitter voltage V _CE of the transistor Q ₂ in the case of a, d of FIG. 6 shows the collector-emitter voltage V _CE of the transistor Q ₂ in the case of b.

However, in a device including such a power supply voltage fluctuation compensating circuit 3, as shown in FIG. 7, in combination with a phase control dimmer 5, the dimmer 5 outputs ( There is a disadvantage in that the fluctuation compensating circuit 3 operates to prevent satisfactory dimming even if an attempt is made to dimming while suppressing the (lamp voltage) voltage. This inconvenient operation will be described with reference to FIG. By the phase control voltage Vs ₂ (a in FIG. 8) by the dimmer 5, the rectified voltage Vs ₁ is obtained as shown in b of FIG. Here, the case where the off period is short is represented by c, and the case where the off period is large is represented by d. As a result, the voltage V _R2 of the resistor R ₂ is inversely proportional to the size of the off period, and V _{R2 (c)} > V _{R2 (d)} , depending on the size of the off period.

Also, the capacitor C₂To start charging to
θc <θd, but the applied voltage is V _{s1 (c)}<V_{s1 (d)}Yo
However, because the charging curve is steeper when d is
Star Q₂The oscillation start phase of the
I can't get it.

[0010]

In the lighting device having the power supply voltage fluctuation compensating circuit 3 as described above, the dimmer 5 is used.
However, there is a problem that a sufficient light control operation cannot be performed when the phase control is performed by. The present invention has been provided in view of the above points, and a high-frequency lighting device capable of performing a sufficient power supply voltage fluctuation compensation operation in the full lighting state and performing smooth dimming lighting even during dimming in phase control. The purpose is to provide.

[0011]

According to the present invention, there is provided a high frequency power supply comprising an inverter circuit which uses a pulsating current power source obtained by full-wave rectifying a commercial power supply as a power source, and a lamp which is lit by high frequency power supplied from the inverter circuit. In the lighting device, the input voltage to the inverter circuit is detected, and a control signal generated based on the voltage is used to keep the output to the inverter circuit constant, and a period of the voltage input to the inverter circuit is predetermined. A control means for stopping the operation of the power supply voltage fluctuation compensating circuit when the width becomes equal to or larger than the width is provided.

[0012]

Thus, at the time of full lighting, the power supply voltage fluctuation compensating circuit keeps the lamp voltage constant against fluctuations in the power supply voltage, flickering can be prevented, and the reliability of the circuit can be improved. During dimming in which the period of the voltage input to the inverter circuit changes, the operation of the power supply voltage fluctuation compensating circuit can be stopped, and dimming proportional to the phase control angle can be smoothly performed.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, an AC power supply AC is input to a rectifier Re via a dimmer 5, and a phase control width detection circuit 1, a power supply voltage fluctuation compensation circuit 3, and an inverter are provided between output terminals of the rectifier Re. The circuit 4 is connected in parallel.
The output terminal of the phase control width detection circuit 1 is connected to the power supply voltage fluctuation compensation circuit 3 via the compensation stop circuit 2.

[0014] Phase control width detection circuit 1 is connected a series circuit of a resistor R _4, R ₅ across the rectifier Re, the resistor R _4,
Zener diode ZD ₁ midpoints of R _5, inverter gates G _1, resistors R ₆ and via a capacitor C _5, and is connected to the other end of the resistor R _5. Also, the capacitor C ₅
A series circuit of a Zener diode ZD ₂ and a resistor R ₇ is connected to both ends of each of them, and the midpoint thereof is connected to the gate of the thyristor Q ₄ . The anode of the thyristor Q ₄ constituting the compensation stop circuit 2 is connected to the positive terminal of the power supply V _cc , and the cathode is connected to the base of the transistor Q ₅ via the resistor R ₈ .

The power supply voltage fluctuation compensating circuit 3 includes the rectifier R
Diode D on both ends of e₁And capacitor C₁Series circuit of
And the capacitor C₁Resistance at both ends of
R₁, R ₂Connect the series circuit of and connect the middle point to PUT
Q₃Zener diode with the anode of
ZD₃Through transistor Q_FiveConnect to the collector of
There is.

The gate of the PUT · Q ₃ is connected to the midpoint of the resistor R ₃ and capacitor C _2, and whose cathode is connected to the base of the transistor Q ₂ of the inverter circuit 4. The inverter circuit 4 is a half bridge circuit similar to the conventional example, and the description thereof is omitted. Next, the circuit operation will be described with reference to FIG. The group A on the left side of FIG. 2 shows the case where the phase control width is small, and the group B on the right side shows the case where the phase control width is large.

First, the group A when the phase control width is small will be described. In this case, the output waveform of the inverter gate G ₁ of the phase control width detection circuit 1 short detection width as shown in B of FIG. 2, therefore, as shown in C of FIG. 2, the charging voltage V of the capacitor C _{5 C5} does not reach the zener voltage V _ZD2 of the zener diode ZD ₂ . Therefore,
Since no voltage is generated in the resistor R ₇ (d in FIG. 2), the thyristor Q ₄ remains off and the transistor Q ₅ remains off (e in FIG. 2).

As a result, the power supply voltage fluctuation compensating circuit 3 operates to keep the lamp voltage constant with respect to fluctuations in the power supply voltage, as in the conventional example. Next, the case of group B will be described. When the phase control width is large, the output width of the inverter gate G ₁ increases as shown in (b) of FIG. 2, and the charging voltage V _C5 of the capacitor C ₅ becomes a zener diode as shown in (c) of FIG. to exceed the Zener voltage V _ZD2 of ZD _2, the Zener diode ZD ₂ is turned on, both ends of the voltage, as shown in two of FIG. 2 of the resistor R ₇ is generated.

Due to the generation of this voltage, the thyristor Q_FourTo
Triggered, Thyristor Q_FourTurns on. This rhino
Lista Q_FourPower source V_ccIs being applied
Therefore, once it is turned on, it will be latched.
As shown, transistor Q _FiveTurn on. This tiger
Register Q_FiveWhen is turned on, PUT of compensation stop circuit 2
Q₃Anode voltage V_R2However, as shown in FIG.
Ener diode ZD₃Zener voltage V_ZD3Fixed to
Capacitor C that is proportional to the fluctuation of the power supply voltage₁
Voltage V_C1Is no longer affected by the
Stop functioning.

With the above operation, in the apparatus of FIG.
During phase control close to full lighting, the lamp voltage is kept constant regardless of fluctuations in the power supply voltage, and it is possible to prevent a decrease in lamp life due to flicker or overvoltage application. , Dimming lighting is possible. (Embodiment 2) Embodiment 2 is shown in FIG. This embodiment also comprises a phase control width detection circuit 1, a compensation stop circuit 2, a power supply voltage fluctuation compensating circuit 3 and an inverter circuit 4, as in the previous embodiments.

The phase control width detection circuit 1 has a series circuit of resistors R ₁ and R ₂ connected to both ends of a rectifier Re, and a midpoint between the Zener diode ZD ₁ and an inverter gate G ₁ of an AND gate G ₂ . It is connected to one end of the input terminal. The other end of the input of the AND gate G ₂ is connected to the output terminal of the pulse oscillation circuit 11, and the output terminal of the AND gate G ₂ is connected to the counter circuit 12.

The compensation stop circuit 2 is composed of the counter circuit 12 described above.
With an output terminal connected through a resistor R _7, it is connected to the gate of the thyristor Q _6. This thyristor Q ₆
Is connected to the base of the transistor Q ₅ . The power supply voltage fluctuation compensating circuit 3 has a series circuit of a diode D ₂ and a capacitor C ₄ connected in parallel to both ends of the rectifier Re, resistors R ₄ and R ₅ connected to both ends of the capacitor C ₄ , and a middle point thereof. Is connected to the emitter of transistor Q ₃ . The base of the transistor Q ₃ is grounded via the collector-emitter of the transistor Q ₄ ,
The base of the transistor Q ₄ is connected to the control power supply V _cc and the collector of the transistor Q ₅ . The collector of the transistor Q ₃ is input to the inverter circuit 4 via the diode D ₃ .

The inverter circuit 4 is a general one-stone separately-excited inverter circuit using a switching regulator IC (for example, μPC1094) 41. This circuit
The oscillation frequency can be arbitrarily set by the capacitor C ₃ and the resistor R ₈ connected to pins 5 and 6 of the IC 41, and the on-duty can be arbitrarily changed by the voltage input to the pin 1 to control the output voltage. it can.

Diode D _{3 of} power supply voltage fluctuation compensating circuit ₃
The cathode of is connected to pin 1 of IC41,
The collector of the transistor Q ₂ is the 1 pin, the emitter of the transistor Q ₂ is connected to the 14 pin through a resistor R _7, the base of the transistor Q ₂ is input to the collector of the transistor Q _5. Next, the circuit operation will be described with reference to FIG. As in the previous embodiment, groups A and B will be described separately for each case. In group phase control width is small A, the output of the inverter gate G ₁ and (B in FIG. 4), the output of the pulse oscillator circuit 11 and (C in FIG. 4) is input to an AND gate G _2, the AND gate G ₂ 4 to 4 are input to the counter circuit 12.

[0025] However, when the number of pulses determined arbitrarily counter circuit 12 is not input, as shown in E of FIG. 4, the output of the counter circuit 12 does not become H level, the thyristor Q ₆ is shown in FIG. 4 f Since the transistor Q ₅ remains off as shown in FIG. 4 (FIG. 4G), the transistor Q ₄ turns on, the transistor Q ₂ turns off, and I
A voltage of V _R5 , which is proportional to the power supply voltage fluctuation, is applied to pin 1 of C41, and the power supply voltage fluctuation compensating circuit 3 operates.

Further, in the group B having a large phase control width, the number of pulses from the AND gate G ₂ exceeds a certain number as shown in FIG. 4D, so that the output of the counter circuit 12 is shown in E of FIG. Thus, the H level is reached, and the thyristor Q ₆ is turned on as shown in FIG. Thyristor Q
_When the transistor ₆ turns on, the transistors Q ₅ (G in FIG. 4) and Q ₂ turn on, and the transistors Q ₄ and Q ₃ turn off. Therefore, the pin R of the IC 41 has resistors R ₇ and R ₆ . A uniquely determined voltage is applied, the on-duty is fixed, the power supply voltage fluctuation compensating circuit 3 does not operate, and power corresponding to the phase control angle is applied to the lamp L, enabling dimming lighting.

[0027]

As described above, the present invention provides a high frequency wave including an inverter circuit which uses a pulsating current power source obtained by full-wave rectifying a commercial power source as a power source, and a lamp which is lit by the high frequency power supplied from the inverter circuit. In the lighting device, the input voltage to the inverter circuit is detected, and a control signal generated based on the voltage is used to keep the output to the inverter circuit constant, and a period of the voltage input to the inverter circuit is predetermined. Since the control means is provided to stop the operation of the power supply voltage fluctuation compensating circuit when it exceeds the width, the lamp voltage is kept constant by the power supply voltage fluctuation compensating circuit against the fluctuation of the power supply voltage at the full lighting. To prevent flicker, improve circuit reliability, and change the period of voltage input to the inverter circuit during dimming. The operation of the power supply voltage variation compensating circuit is stopped, in which the effect which can perform dimming proportional to the phase control angle smoothly.

[Brief description of drawings]

FIG. 1 is a specific circuit diagram of an embodiment of the present invention.

FIG. 2 is an operation waveform diagram of FIG. 1 above.

FIG. 3 is a specific circuit diagram of the second embodiment of the above.

FIG. 4 is an operation waveform diagram of FIG. 3 above.

FIG. 5 is a specific circuit diagram of a conventional example.

FIG. 6 is an operation waveform diagram of FIG.

FIG. 7 is a block diagram of a conventional example when a dimmer is combined.

FIG. 8 is an operation waveform diagram of FIG. 7.

[Explanation of symbols]

 1 Phase control width detection circuit 2 Compensation stop circuit 3 Power supply voltage fluctuation compensation circuit 4 Inverter circuit

Claims (1)

[Claims] 1. A high-frequency lighting device comprising: an inverter circuit using a pulsating current power source obtained by full-wave rectifying a commercial power source as a power source; and a lamp lit by high-frequency power supplied from the inverter circuit. Of the power supply voltage fluctuation compensating circuit that keeps the output to the inverter circuit constant by the control signal generated based on the detection of the input voltage, and when the period of the voltage input to the inverter circuit exceeds a predetermined width. A high frequency lighting device comprising a control means for stopping the operation of a power supply voltage fluctuation compensating circuit.