JP2989755B2 - Lighting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device for rectifying an AC power supply voltage, converting the voltage to a high frequency, and lighting a lamp such as an incandescent lamp with the high frequency power.

[0002]

2. Description of the Related Art FIG. 3 is a circuit diagram of a conventional lighting device.

This lighting device comprises a lighting circuit 1 and a dimming circuit 2
It is composed of

The lighting circuit 1 includes a rectifier Re1 and a half-bridge type transistor inverter circuit.
That is, between the output terminals of the rectifier Re1, a pair of transistors Q1 and Q2, which are switch elements, and each transistor Q1,
A pair of resistors R1 respectively connected to the emitter of Q2,
A series circuit with R2 and a series circuit with a pair of capacitors C1 and C2 are connected in parallel. Each transistor Q1, Q
2 and a series circuit of resistors R1 and R2 are connected in reverse parallel with diodes D1 and D2 for reflux, respectively. A series circuit of a primary winding of the step-down transformer T1 and a primary winding of the feedback transformer T2 is connected between a connection point between the capacitors C1 and C2 and a connection point between the resistor R1 and the collector of the transistor Q2. .

An incandescent lamp LP is connected to the secondary winding of the step-down transformer T1. Both ends of a pair of secondary windings of the feedback transformer T2 are connected to the base-emitter of each of the transistors Q1 and Q2 and the resistor R1. , R2. The two secondary windings of the feedback transformer T2 are connected to the transistors Q1 and Q2 so that the phases are opposite to each other. A noise filter including a capacitor C4 and a choke coil CH is provided in a stage preceding the rectifier Re1.

The lighting circuit 1 is provided with a starting circuit S including a resistor R3, a capacitor C3, and a trigger element (SBS or the like) Q3. That is, the resistor R3 and the capacitor C
3 is connected between both ends of the series circuit of the capacitors C1 and C2, the voltage between both ends of the capacitors C1 and C2 becomes equal to or higher than a predetermined voltage, and the terminal of the capacitor C3 is connected to the trigger element Q3 via the resistor R3. When the battery is charged up to the breakover voltage, the trigger element Q3 is turned on to turn on the transistor Q2.

The diode D3 is connected to the transistor Q
2 is provided to prevent charging of the capacitor C3 during repeated ON and OFF, and when the oscillation operation is stopped, the capacitor C3 is recharged.

On the other hand, a dimming circuit 2 for controlling the phase of the commercial power supply AC is provided between the commercial power supply AC and the lighting circuit 1, and turns on the phase control element Q4 such as a triac and the phase control element Q4. And a trigger circuit for causing the resistors R4 to R6, the capacitor C5,
It is constituted by a trigger element Q5.

When the capacitor C5 is charged and the terminal voltage reaches the breakover voltage of the trigger element Q5, the trigger element Q5 is turned on and the phase control element Q4 is turned on. Note that the phase control element Q
The firing angle of 4 is adjusted by the resistor R5.

Next, the operation will be described.

When the phase control element Q4 of the dimming circuit 2 is turned on, the AC power supply voltage is full-wave rectified by the rectifier Re1, and the capacitors C1, C2 and C3 are charged. When the transistor Q2 is activated (turned on) by the activation circuit S (by the charging voltage of the capacitor C3) in a state where the capacitors C1 and C2 are charged, the electric charge charged in the capacitor C2 is transferred to the primary winding of the step-down transformer T1. It is emitted through a path of line → primary winding of feedback transformer T2 → transistor Q2.

At this time, a current flows in the secondary winding of the feedback transformer T2 so as to forward bias the transistor Q2 (therefore, the transistor Q1 is reverse-biased and turned off). Thereafter, the current flowing through the primary winding of the feedback transformer T2 is limited to a current corresponding to the equivalent resistance of the incandescent lamp LP, and no current flows through the secondary winding of the feedback transformer T2, and the transistor Q2 is turned off. I will head. Therefore, a current that reversely biases the transistor Q2 and forward biases the transistor Q1 flows through the secondary winding of the feedback transformer T2. As a result, the transistor Q1 is turned on and the electric charge stored in the capacitor C1 is turned on. From the transistor Q1 → the primary winding of the feedback transformer T2 → the step-down transformer T1.

This operation is repeated to perform an oscillation operation. That is, the pulsating current output from the rectifier Re1 is converted into a high frequency, and the high frequency power turns on the incandescent lamp LP.

[0014]

In the above-mentioned conventional circuit, when the breakover voltage of the trigger element Q3 is high, the phase control element Q4 is turned on and then the time constant circuits R3 and C3 connect the capacitor C3. The time required before the trigger element Q3 breaks over by charging is inevitably long. That is, since a time delay occurs from the turning on of the phase control element Q4 to the activation of the lighting device 1, the input current greatly changes to become an oscillating current, and the phase control element Q4 is turned off near the zero cross of the oscillating current. There is a problem that the incandescent lamp LP may flicker.

If the breakover voltage of the trigger element Q3 is high, the peak value of the power supply voltage is low near the phase 0 ° (180 °) when the phase control element Q4 is turned on. Without this, the high-frequency oscillation operation cannot be started. That is, the upper limit of dimming becomes lower near the phase 0 ° when the phase control element Q4 is turned on, and the lower limit of dimming becomes higher near the phase of 180 °, resulting in a problem that the dimming range becomes narrower. .

One way to avoid these problems is to use an element with a low breakover voltage (for example, about several volts), for example, SBS, as the trigger element Q3. However, in this case, no problem occurs when a rated lamp load is connected, but the following problem occurs when a new lamp is replaced due to lamp burnout.

When the phase control element Q4 is turned on in a state where the lamp is cut off (hereinafter referred to as no load),
When the capacitor C3 of the time constant circuits R3 and C3 is charged and the charging voltage reaches the breakover voltage of the trigger element Q3, the trigger element Q3 breaks over. Then, the SBS, which is the trigger element Q3, has a property of holding the ON state if there is a sufficient ON voltage and holding current after the breakover, so that a sufficient ON voltage and holding current are given, and thereafter the ON state is changed. Hold. The reason for this is that the voltage and current source to the trigger element Q3 are obtained by smoothing the output voltage of the rectifier Re1 by the voltage dividing capacitors C1 and C2. C
This is because the DC power is stored in the power supply 2 and a sufficient ON voltage and sufficient holding current are supplied to the trigger element Q3.

Thus, when no load is applied, the trigger element Q3 once turned on keeps the on state thereafter. At this time,
Since the DC current from the trigger element Q3 flows through the secondary winding on the transistor Q2 side of the feedback transformer T2, the impedance of this secondary winding can be ignored. In this state, even if a new lamp is attached, the feedback transformer T2 is not driven, so that the high-frequency conversion operation does not start and the lamp does not light.

In order to turn on this new lamp,
It is necessary to turn off the power supply AC once and return the trigger element Q3 to the off state. Particularly, in a place where many lamps are used such as a commercial facility, the power supply is turned off each time one lamp is cut off and replaced. It is inconvenient to turn off all lamps.

Accordingly, an object of the present invention is to provide a lighting device for rectifying an AC power supply, converting the AC power into a high frequency, and supplying the rectified power to a lamp.
If the lamp burns out, install a new lamp,
Another object of the present invention is to automatically turn on a new lamp without resetting the power.

Another object of the present invention is to reduce the oscillating current by shortening the delay from turning on the phase control element of the dimming circuit to starting the lighting device when the dimming circuit is connected. An object of the present invention is to prevent flickering of a lamp and to secure a wide dimmable range of the lamp.

[0022]

SUMMARY OF THE INVENTION The present invention relates to a lighting device for rectifying an AC power supply voltage with a rectifier, converting the output of the rectifier to a high frequency by a high frequency conversion circuit, and supplying the high frequency to a lamp. And a starting circuit for starting the high-frequency conversion circuit.

In a preferred embodiment, the starting circuit has a capacitor which is charged by the voltage at the preceding stage of the rectifier, and a trigger element which breaks over by the charging voltage of the capacitor and starts the high frequency conversion circuit. .

[0024]

The lighting device of the present invention rectifies an AC power supply voltage with a rectifier, converts the output of the rectifier into a high frequency by a high frequency conversion circuit, and supplies the high frequency to the lamp, thereby lighting the lamp. An activation circuit for activating the high-frequency conversion circuit operates by receiving power supply not from the output of the rectifier but from an AC voltage in a stage preceding the rectifier.

Since the voltage before the rectification always has a zero cross point, the instant when the voltage passes through the zero cross point, the start circuit operates in the same manner as when the power is turned off and on again. For this reason, even when there is no load, a state similar to the power reset is given to the lighting device every time the zero-cross point passes, and when a new lamp is mounted, the high-frequency conversion operation is restarted and the lamp is lit.

Because of this automatic relighting function,
As a configuration of the start-up circuit, a configuration in which the capacitor is charged and the trigger element is broken over by the charged voltage is adopted. Even if an element such as SBS having a sufficiently low breakover voltage is used as the trigger element, there is no problem. No problem. As a result, when used in connection with a dimming circuit, the time from turning on of the phase control element to activation of the lighting device can be sufficiently reduced, so that flickering of the lamp can be prevented and a wide dimming range can be secured. be able to.

[0027]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The same parts as those in the conventional example shown in FIG. 3 are denoted by the same reference numerals, and duplicate description will be omitted.

FIG. 1 is a circuit diagram of an incandescent lamp lighting device according to one embodiment of the present invention.

As shown in FIG. 1, the basic configuration of the apparatus of this embodiment, that is, a dimming circuit 2 for controlling the phase of a commercial power supply AC by a phase control element Q4, and a commercial power supply voltage controlled by the dimming circuit 2 Is similar to the conventional device shown in FIG. 3 in that the lighting circuit 1 is rectified, converted to a high frequency by a half-bridge type transistor inverter, and supplied to the incandescent lamp LP.

One feature of the configuration of this embodiment different from the conventional device is that a trigger element (SBS) of the lighting circuit 1 is provided.
The point that the voltage source of the starting circuit S to Q3 is not the output of the rectifier Re1 but the preceding stage of the rectifier Re1.

That is, the diodes D4 and D5 are respectively connected to the two input lines L1 and L2 at the preceding stage of the first rectifier Re1.
Are connected to form a second rectifier Re2 parallel to the first rectifier Re1, and the second rectifier Re2
, A resistor R3 and a capacitor C3 are connected in series. Therefore, the alternating half-wave voltages of the input lines L1 and L2 are rectified by the diodes D4 and D5,
The capacitor C3 is charged through the resistor R3.

Incidentally, SBS having a breakover voltage of about several volts is used for the trigger element Q3.

Regarding the circuit operation of this embodiment, when the rated incandescent lamp LP is connected (hereinafter referred to as a load), the voltage source of the starting circuit S is in front of the rectifier Re1 in FIG. Even if it is different from the conventional circuit, the operation itself is the same as the conventional circuit.

On the other hand, when there is no load, almost no current flows through the lighting circuit 1, so that the phase control element Q4 cannot be turned on due to insufficient ON current.
Is added (see FIG. 2). Since the power supply voltage AC is applied to the time constant circuits R3 and C3 through the diodes D4 and D5, the capacitor C3 is charged. When the charged voltage reaches the breakover voltage of the trigger element Q3, the trigger element Q3 breaks over and turns on. Becomes

Thereafter, when the output voltage of the dimming circuit 2, which is the power supply of the trigger element Q3, approaches zero volts, the trigger element Q3 cannot maintain the ON state and turns off once, but the output voltage of the dimming circuit 2 becomes zero cross. When the current rises after passing through the point, the trigger element Q3 breaks again due to the charging of the capacitor C3. In this way, the trigger element Q3 breaks over every time the output voltage of the dimming circuit 2 passes through the zero cross point, that is, every half cycle of the power supply sine wave (see FIG. 2).

In this state, when the trigger element Q3 is in the on state, the DC current from the trigger element Q3 flows through the secondary winding on the transistor Q2 side of the feedback transformer T2, so that the impedance of this secondary winding is ignored. However, the excitation is temporarily performed at the moment when the trigger element Q3 breaks over every half cycle of the power supply sine wave.

Therefore, when a new incandescent lamp LP is mounted in this no-load state, the secondary winding of the feedback transformer T2 is momentarily excited every half cycle of the sine wave. Drives the transistor Q2 to turn on, the high-frequency conversion operation starts, and the incandescent lamp LP is turned on. That is, there is no need to turn off and on the power to turn on the new incandescent lamp LP.

Also, since SBS having a low breakover voltage is used as the trigger element Q3, the capacitor C3
Can shorten the charging time until the battery reaches the breakover voltage. As a result, a time delay from when the phase control element Q4 of the dimming circuit 2 is turned on to when the starting circuit S is started can be minimized, and flickering of the incandescent lamp LP can be prevented. Further, the trigger element Q
3 is sufficiently low, the lighting circuit operates even in a phase near 0 ° and 180 ° where the peak value of the output voltage of the dimming circuit 2 is low, so that dimming can be performed over a wide range. become able to.

The lighting device for an incandescent lamp has been described as an embodiment, but the present invention can be applied to a lighting device for a lamp other than an incandescent lamp.

[0040]

As described above, according to the present invention,
The lamp can be turned on at the same time as the replacement is completed without turning off the power when replacing the lamp, and when a dimming circuit is connected, the flicker of the lamp is prevented and the dimming range of the lamp is widened. Can be.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an incandescent lamp lighting device according to one embodiment of the present invention.

FIG. 2 is a waveform chart for explaining an operation at the time of no load of the embodiment.

FIG. 3 is a circuit diagram of an incandescent lamp lighting device according to a conventional example.

[Explanation of symbols]

 Reference Signs List 1 lighting circuit 2 dimming circuit S starting circuit Re1, Re2 rectifier LP incandescent lamp R3 resistor C3 capacitor D4, D5 diode Q3 trigger element

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tadashi Akashi 3-18-16 Negishi, Taito-ku, Tokyo Inside Tokyo Trans Co., Ltd. (56) References JP-A-4-48593 (JP, A) JP-A Sho 52 −61374 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H05B 37/00-41/46

Claims (2)

(57) [Claims] 1. A lighting device for rectifying an AC power supply voltage with a rectifier, converting the output of the rectifier into a high frequency by a high frequency conversion circuit, and supplying the high frequency to a lamp, wherein the high frequency conversion circuit receives the AC voltage of the preceding stage of the rectifier. A lighting device comprising a starting circuit for starting the lighting device. 2. The device according to claim 1, wherein the starting circuit includes a capacitor charged by a voltage of the preceding stage of the rectifier, and a trigger element that breaks over by a charging voltage of the capacitor and starts a high-frequency conversion circuit. A lighting device, comprising: