JP2790133B2 - Lighting control device and lamp lighting device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting control device and a lamp lighting device for dimming and lighting a lamp such as a fluorescent lamp or an incandescent lamp. (Prior Art 1) Conventionally, as described in, for example, JP-A-61-296699, by changing the operating frequency of a high-frequency lighting device, an inductive limit interposed between the high-frequency lighting device and a discharge lamp is known. There is known a device that dims a discharge lamp by changing the impedance of a flow element. In this device, a variable frequency square wave signal from an oscillation circuit unit is integrated by a two-phase division circuit unit to form a substantially triangular wave, and the triangular wave is compared with a reference value, and a pair of switching elements are both turned off. A control signal including a period is created. In the prior art 1, the frequency of the square wave signal is twice as high as the operating frequency of the high frequency lighting device. Therefore, by changing the frequency of the square wave, the operating frequency of the high-frequency lighting device changes, and the discharge lamp can be dimmed and lit. (Prior Art 2) For example, Japanese Patent Application Laid-Open
As described in JP-A-88499, there is also known an apparatus that controls a high-frequency lighting device based on a PWM signal to dimm the lamp. That is, the high-frequency lighting device generates a high-frequency output having a waveform, for example, as shown in FIG. 3C modulated by the PWM signal, based on the PWM dimming signal having a duty ratio corresponding to the dimming level. The output is supplied to the lamp to dimm the lamp. 3A shows a voltage waveform of an AC power supply, for example, a commercial power supply of 50 or 60 Hz, and FIG. 3B shows a PWM signal waveform.
This PWM signal is turned on (for example, 12
The V) period is set to be long and the OFF (OV) period is set to be short. (C) is a lamp current waveform,
During the ON period of the PWM signal, the frequency of the high-frequency output is high (for example, 50 kHz) and the lamp current is small (for example, 70 m).
A). On the other hand, the frequency is low during the off period (for example, 40 kHz).
z) The lamp current increases (for example, 330 mA). [0004] In the prior art 1, dimming is performed by changing the frequency of a square wave signal which is twice the operating frequency of the high-frequency lighting device. Since the high-frequency lighting device operates at several tens of kHz, the square wave signal is twice as high as this. Therefore, if the oscillation circuit section that generates the square wave signal and the two-phase splitting circuit section are far apart, the high-frequency square wave signal is easily attenuated by stray capacitance and the like, and the square wave signal is affected by electrical noise and the like. There is a concern that the shape of the signal is likely to fluctuate, and therefore, the accuracy of dimming is reduced. There is also a problem that high-frequency noise is generated by transmitting a high-frequency square wave signal, which affects other electric devices. In a high-frequency lighting device that generates a high-frequency output modulated by a PWM signal as in the above-mentioned prior art 2, the lamp current has a waveform having a large ripple, and therefore, a beat sound is generated or an electronic signal is generated. There is a problem that it causes stress to parts. SUMMARY OF THE INVENTION It is an object of the present invention to provide a lighting control device and a lamp lighting device that can improve the accuracy of dimming and reduce the generation of harmonic noise, beat noise, and stress on electronic components. A lighting control device according to a first aspect of the present invention includes a high-frequency generator for converting a low-frequency alternating current into a high-frequency power; and a dimmable and illuminable lamp energized by the high-frequency generator. And a dimming signal transmitting device for transmitting a PWM signal; a PWM signal being input, generating a DC signal according to the duty ratio, controlling the output of the high frequency generator with a control signal corresponding to the DC signal, A control device for converting a detection signal corresponding to the lamp current value of the lamp into a direct current and changing the direct current signal so that the lamp current value is constant. In the present invention, a dimming signal transmitting device transmits a PWM signal indicating a dimming level of a lamp. The control device receives the PWM signal transmitted from the dimming signal transmitting device, generates a DC signal according to the duty ratio, and generates a control signal according to the DC signal. The high-frequency generator operates under the control of the control signal,
For example, as shown in FIG. 2B, high-frequency power of, for example, 20 kHz to 100 kHz is generated so as to change the optical output. The lamp is turned on by this high frequency power. here,
Since the signal transmitted from the dimming signal transmitting device to the control device as described above is a PWM signal, the duty ratio does not change even if the voltage value of the signal changes due to transmission loss or the like. The lamp current does not cause the ripple of 100 Hz or 120 Hz as shown in FIG. Further, since the detection signal corresponding to the lamp current value of the lamp is converted into a DC signal to change the DC signal, the lamp current value can be stabilized even when the low-frequency AC power supply voltage fluctuates, that is, the light output can be stabilized. Since such a constant control is performed by converting a detection signal into a DC signal with respect to a DC signal, the handling of the signal is easy and the configuration can be simplified. According to a second aspect of the present invention, there is provided a lighting control apparatus.
In the described invention, the lamp is a discharge lamp,
The control device is characterized by having lamp voltage detection means for detecting a voltage corresponding to the voltage between both ends of the discharge lamp and generating a DC signal for reducing or stopping the output of the high frequency generator when abnormally high voltage is detected. . The present invention further reduces the output of the high frequency generator when the voltage across the discharge lamp becomes abnormally high, for example, when no load is applied. Therefore, danger of electric shock due to continuous output of a high no-load voltage, deterioration and destruction of components, and the like can be prevented. A lamp lighting device according to a third aspect of the present invention includes a high-frequency generator for converting a low-frequency alternating current into a high-frequency power; a dimmable lamp that is activated by the high-frequency generator;
A WM signal is input, a DC signal corresponding to the duty ratio is generated, the output of the high frequency generator is controlled by a control signal corresponding to the DC signal, and a detection signal corresponding to the lamp current value of the lamp is converted to DC. And a control device for changing the DC signal so that the lamp current value is constant. The lamp lighting device of the present invention has the same function as the control device and the high frequency generator in the above-mentioned lighting control device. That is, the control device receives the PWM signal transmitted from the dimming signal transmitting device, generates a DC signal corresponding to the duty ratio, and generates a control signal corresponding to the DC signal. The high-frequency generator operates under the control of the control signal to generate high-frequency power.
Since the signal transmitted from the dimming signal transmitting device to the control device as described above is a PWM signal, the duty ratio does not change even if the voltage value of the signal changes due to transmission loss or the like. Further, the high-frequency generator generates high-frequency power by a control signal corresponding to a DC signal generated based on the duty ratio, and the high-frequency power turns on the lamp, so that a large ripple does not occur in the lamp current waveform. Further, the light output of the lamp can be made constant with a simple configuration. According to a fourth aspect of the present invention, in the third aspect of the present invention, the lamp is a discharge lamp, and the control device detects a voltage corresponding to a voltage between both ends of the discharge lamp. It is characterized by having a ramp voltage detecting means for generating a DC signal for reducing or stopping the output of the high frequency generator. The present invention operates in the same manner as the second aspect of the present invention. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a lighting control device and a lamp lighting device according to an embodiment of the present invention. The lighting control device includes a high-frequency generator A, a controller B, a dimming signal transmitter C, and a lamp 9 as shown in FIG. Hereinafter, each device will be described in detail. AC is an AC power supply, and a rectifier circuit 2 including a full-wave rectifier 21 and a smoothing capacitor 22 is connected to the AC power supply AC via an L-type filter circuit including an inductor 11 and a capacitor 12 for preventing noise. . Between the positive and negative DC output terminals of the rectifier circuit 2, two power MOs connected by SEPP are provided.
Separately-excited inverter circuit 3 having SFETs 31 and 32
Is connected. 4 is an activation circuit, 5 is a control system power supply circuit, 6 is a DC signal generation circuit, 7 is a Vf converter, 8 is V
This is a drive circuit for performing push-pull driving of the FETs 31 and 32 by the high frequency output of the −f converter 7. The inverter circuit 3 is of a type called a series inverter or a half bridge, and has two power MOSFs between the positive and negative DC output terminals of the rectifier circuit 3.
A series circuit of ET31 and ET32 and a series circuit of two DC cut capacitors 33 and 34 are connected, and a leakage type inverter transformer 35 is connected between a connection point between FETs 31 and 32 and a connection point between capacitors 33 and 34. The primary winding 35p is connected. A resonance capacitor 36 is connected to the secondary winding (lamp current supply winding) 35s of the transformer 35, and the lamp 9 such as a fluorescent lamp is connected via a current transformer (CT) 37. ing. 35f1 and 35
f2 is a filament power supply winding connected to the filaments 9f1 and 9f2 of the lamp 9, respectively. The transformer 35 further includes an output voltage detecting winding 3.
5d is provided. The control signal generation circuit 6 includes a lamp current detection means 61, a DC conversion circuit 62, a lamp voltage detection means 63, and an error amplifier 64. The lamp current detecting means 61 detects a detection voltage V proportional to the lamp current IL from the secondary winding induced output of CT37.
Generate ID. The DC conversion circuit 62 includes a photocoupler 65,
It comprises a transistor 66, a resistor 67, a capacitor 68, etc., receives a PWM dimming signal transmitted from the dimming signal transmitting device C, converts the PWM signal into a DC signal VPM, and converts the DC signal VPM to the detection voltage VID. As a DC bias. The lamp voltage detecting means 63 generates a voltage proportional to the lamp voltage VL from the induced output of the output voltage detecting winding 35d of the inverter transformer 35. The error amplifier 64 outputs an error voltage VER proportional to a difference voltage between a higher voltage between the output voltage VPM + VID of the DC conversion circuit 62 and the output voltage of the ramp voltage detecting means 63 and the reference voltage VREF. In the present embodiment, the lamp voltage detecting means 63 is used to reduce or cut off the output of the inverter circuit 3 when a load abnormality such as a lamp load release occurs, and during normal operation, the output voltage VPM + VID of the DC conversion circuit 62. Is set to be higher than the output voltage of the lamp voltage detection circuit 63. Next, the operation of the lighting control device and the lamp lighting device will be described. AC power supply AC through a switch (not shown)
Is input and a low-frequency AC is input, the rectifier circuit 2
A smoother rectified output is generated, which is supplied to the inverter circuit 3. Further, DC voltage Vcc is applied to control signal generation circuit 6, Vf converter 7 and drive circuit 8 via start circuit 4 and control system power supply 5, respectively. This allows
The Vf converter 7 outputs a control signal composed of a high-frequency voltage. Then, the control signal is supplied to the gates of the FETs 31 and 32 of the inverter circuit 3 of the high frequency generator via the drive circuit 8, and the high frequency generator A operates. Then, the FETs 31 and 32 drive the primary winding 35p of the inverter transformer 35, and a high-frequency voltage is induced in the secondary winding 35s of the inverter transformer 35. The starting circuit 4 reduces the output voltage Vcc of the control system power supply 5 to reduce the high frequency output power of the inverter circuit 3 for a predetermined time after the AC power supply AC is turned on. This prevents a so-called cold start that lights up without being heated sufficiently. When the predetermined time elapses, the output voltage Vcc of the control system power supply 5 returns to a steady value, and the lamp 9 is applied with a high-frequency voltage sufficiently higher than the discharge starting voltage from the inverter circuit 3 and lights. At the time of steady lighting, the lamp current IL has a value (hereinafter, referred to as a value) corresponding to the dimming level given by the PWM dimming signal.
Command value), the current transformer (CT) 3
Lamp current detecting means 6 for detecting the secondary winding induced output 7
1 increases the output voltage VID. Then, the DC conversion circuit 6
2, the output voltage VPM + VID increases, the error voltage VER increases, the output from the Vf converter 7 increases, and the output frequency of the inverter circuit 3 increases. Here, the leakage inductance of the inverter transformer 35 acts as an inductive impedance, and the lamp current IL decreases as the output frequency of the inverter circuit 3 increases. On the other hand, when the lamp current IL decreases below the above command value, the output frequency of the inverter circuit 3 decreases and the lamp current IL increases, contrary to the above. By this negative feedback operation, the lamp current IL is stabilized at a value near the command value. In the control signal generating circuit 6, the dimming signal transmitted from the dimming signal transmitting device C via, for example, a signal line (not shown)
6 and a voltage having a PWM waveform similar to that of the external light control signal is generated at the collector of the transistor 66. This voltage is applied to the resistor 67 and the capacitor 6
8, a voltage VPM is generated between the terminals of the capacitor 68 in proportion to the pulse width (on-duty ratio) of the external dimming signal. This voltage VPM is added to the detection voltage VID output from the lamp current detection means 61 as a DC bias, and then input to the error amplifier 64. If the pulse width of the external dimming signal is increased, the voltage VPM increases, and the voltage VPM + VID input to the error amplifier 64 increases. This allows
The error voltage VER rises, the control signal output from the Vf converter 7 and the output frequency of the inverter circuit 3 rise, and the lamp current decreases. That is, the light control becomes deep. On the other hand, when the pulse width of the external dimming signal is reduced, the voltage VPM decreases, and the voltage VPM input to the error amplifier 64 is reduced.
+ VID decreases, the error voltage VER decreases, the control signal output from the V-f converter 7 and the output frequency of the inverter circuit 3 decrease, and the lamp current increases. That is, light control becomes shallow. FIG. 2 shows the relationship among the PWM waveform of the external dimming signal, the pulse width (ON duty ratio), the waveform and voltage VPM of the DC signal (DC bias), and the brightness of the lamp 9. Thus, in the apparatus of FIG.
DC bias voltage V by varying the pulse width of the external dimming signal
By varying the PM, the light of the lamp 9 can be adjusted. According to the above embodiment, the dimming signal transmitted from the dimming signal transmitting device C to the control device B is a PWM signal, so that the dimming signal is transmitted due to transmission loss between the dimming signal transmitting device and the control device. The duty ratio does not change even if the voltage value of the signal changes. Further, the operation of the high-frequency generation circuit is controlled by a control signal corresponding to the DC signal generated based on the duty ratio of the PWM signal to generate high-frequency power, so that the ripple of the lamp current can be greatly improved. FIGS. 4 to 6 show other embodiments of the present invention, and show modifications of the high frequency generator A shown in FIG. FIG. 4 shows a modification of the high frequency generator of FIG. 1 for two lamps. The inverter transformer 35 is provided with a filament power supply winding 35f3 for a filament commonly connected to the lamps 9a and 9b. FIG. 5 shows an inverter circuit called a modified half bridge in which the DC cut capacitor of the inverter circuit of FIG. 1 is reduced to one. FIG. 6 shows a half-bridge type inverter circuit configured without a transformer. Note that the present invention is not limited to the above-described embodiment, and can be appropriately modified and implemented. For example, in the above description, an example was described in which the on-duty of the PWM dimming signal was converted to a DC signal level, but the off-duty may be converted to a DC signal level. The present invention also provides a lamp lighting device using various high-frequency generators capable of varying a lamp current according to a DC voltage, in addition to the inverter circuit having the configuration shown in FIGS. 1 and 4 to 6 described above. Applicable to electronic ballasts. Further, as the PWM signal, in addition to the rectangular wave signal described above, a sine wave signal or the like whose phase is controlled as in a conventional phase control type dimmer can be used. However, in this case, it is necessary to provide a separate power supply line for supplying a power supply that is not phase-controlled. In the above-described embodiment, as a means for transmitting a PWM signal from a dimming signal transmitting device to a lamp lighting device, a signal is transmitted by so-called optical coupling using a photocoupler. However, the PWM signal may be transmitted by a wired or wireless means. Furthermore, in the above embodiment, the output frequency of the high frequency generating circuit is changed, and the lamp is dimmed by forming an inductive current limiting element by the leakage inductance. The lamp may be energized via a capacitive current limiting element such as a capacitor in addition to a simple inductive element. According to the first and third aspects of the present invention,
Since the dimming signal is a PWM signal, the duty ratio does not change even if the voltage value of the signal changes due to transmission loss or the like. The high frequency generator is controlled by a control signal corresponding to the DC signal generated based on the duty ratio to energize the lamp. In addition, the detection signal corresponding to the lamp current value is converted to DC, and the DC signal is changed so that the lamp current value is constant. Therefore, the accuracy of dimming can be improved, harmonic noise and beat noise can be reduced, and stress on electronic components can be reduced. Further, the lamp current value and thus the light output can be made constant with a simple configuration. According to the second and fourth aspects of the present invention, a high voltage is continuously output when the discharge lamp is not mounted and when there is no load, and the risk of electric shock, deterioration and destruction of parts can be prevented. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram of a lighting control device and a lamp lighting device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of operation waveforms of respective parts of the device of FIG. FIG. 4 is an operation waveform diagram of each part of the high-frequency lighting device of FIG. 4. FIG. 4 is a partial circuit diagram of a high-frequency generation device according to another embodiment. FIG. Partial circuit diagram of high-frequency generator according to another embodiment [Description of symbols] A: high-frequency generator, B: controller, C: dimming signal transmitter, AC: AC power supply, 2: rectifier circuit, 3: inverter Circuit, 5: control system power supply, 6: control signal generation circuit, 7: V
-F converter, 9: lamp, 61: lamp current detecting means, 6
3: Lamp voltage detection hand

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H05B 41/38-41/42 H05B 37/02

Claims (1)

(57) [Claims] A high-frequency generator for converting a low-frequency alternating current into a high-frequency power; a dimmable lamp capable of being activated by the high-frequency generator; a dimmer signal transmitter for transmitting a PWM signal;
A WM signal is input, a DC signal corresponding to the duty ratio is generated, an output of the high frequency generator is controlled by a control signal corresponding to the DC signal, and a detection signal corresponding to a lamp current value of the lamp is converted to DC. A control device for changing a DC signal so that a lamp current value is constant; and a lighting control device. 2. The lamp is a discharge lamp, and the control device detects a voltage corresponding to a voltage between both ends of the discharge lamp, and a lamp voltage detecting means for generating a DC signal for reducing or stopping the output of the high frequency generator when abnormally high voltage is detected. The lighting control device according to claim 1, further comprising: 3. A high-frequency generator for converting low-frequency AC into high-frequency power; a dimmable lamp that is energized by the high-frequency generator; a DC signal that receives a PWM signal and generates a DC signal according to the duty ratio; And a control device for controlling the output of the high-frequency generator with a control signal corresponding to the control signal and converting the detection signal corresponding to the lamp current value of the lamp to DC to change the DC signal so that the lamp current value is constant. A lamp lighting device, comprising: 4. The lamp is a discharge lamp, and the control device detects a voltage corresponding to a voltage between both ends of the discharge lamp, and a lamp voltage detecting means for generating a DC signal for reducing or stopping the output of the high frequency generator when abnormally high voltage is detected. 4. The lamp lighting device according to claim 3, comprising: