JPS62249397A - Radio frequency fluorescent lamp lighting controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a control circuit for preheating and dimming in a high-frequency thermal polarity fluorescent lamp lighting circuit. [Prior Art] Conventionally, high-frequency This type of device powered by a power source is, for example,
In other words, in order to obtain an appropriate preheating current, a dedicated winding for the filament of the fluorescent lamp FL is required as shown in FIG. Alternatively, as shown in FIG. 4, a filament transformer FT from a commercial wave power source E was installed.

[Problem that the invention seeks to solve]

However, it is cost-effective to provide a separate preheating winding for the filament in the transformer LT as shown in Figure 3.
In addition, since the preheating current is turned on relatively quickly after the power is turned on, it is also relatively difficult to perform feedback control to keep the preheating current constant.

Further, as shown in FIG. 4, providing a commercial wave filament transformer not only increases cost but also increases weight and bulk. Note that since the preheating current is relatively stable, there is little need for feedback, but although it is thought that preheating current control is possible by providing a switch element on the negative side or the secondary side, [Means for Solving the Problems] The present invention eliminates the drawbacks of the conventional example described above, and at the same time reduces the impedance of the lighting circuit section as seen from the power supply side, except for the moment when the fluorescent lamp is started. The object of the present invention is to obtain a high-frequency fluorescent lamp lighting control device that can maintain substantially the same value both during preheating and during lighting.

Therefore, a variable impedance stabilizer using a magnetic amplifier is interposed between the lamp and the fluorescent lamp, and when preheating the high-frequency fluorescent lamp lighting circuit that performs dimming by variable impedance, the non-power terminal side of the fluorescent lamp is used. The structure is such that an appropriate filament current is obtained by short-circuiting the ballast using a switch element, relay, etc., feeding back the filament voltage or current, and varying the impedance of the ballast using a magnetic amplifier. Example] Hereinafter, one embodiment of the present invention will be described based on FIG.

In the figure, VHF is generally 10 to 100 KHz using a DC/AC converter, etc. fluorescent light,
K is a relay, RMFi observation resistance, Ll.

Ll is a current-limiting inductance element (saturable inductance element), D+, C2, C3 are high-frequency rectifying elements, R1 is a resistor, C+, C2, Cs are capacitive elements, Q
, ij: optical isolator, P and D are photodiodes,
Charging conversion elements such as CdS, wo, wl.

W2 is the winding of the high-frequency isolation transformer HT.The broken line section is a variable impedance stabilizer section, which has a magnetic amplifier consisting of current-limiting inductance elements L1 and L2. In addition, C and C are control circuits, and N and C are normally closed contacts of the relay, so as shown above,
When the power switch S is closed, the voltage induced in the secondary winding W1 causes the preheating current to flow through the filament fA, → normally closed contact N, C → observation resistor RM → filament fJ2 → current limiting inductance. It flows through the path from element L1 to high frequency rectifier D2.

Further, when the Wl Φ side is negative, the preheating current flows in the path of high frequency rectifier C3 → current limiting inductance element Ll → filament fe2 → observation resistor RM− + normally closed contact N, C → filament fat.

However, at this time, by appropriately switching the DC power supply across the capacitor 01, which is obtained by rectifying and smoothing the voltage induced in the high-frequency isolation transformer H, using the optical isolator Ql, the voltage across the capacitor C2 is adjusted, and the current-limiting inductance By superimposing a DC voltage on the elements Ll and Ll, the impedance of the elements Ll and Ll is varied and the preheating current is adjusted to an appropriate value. In this case, the voltage across the observation resistor RM is monitored and the voltage across the optical isolator Q8 is adjusted. PWM (Pulse Width M
By feeding back to the analog control or analog control, it is possible to flow a constant preheating current regardless of voltage fluctuations and frequency fluctuations of the high-frequency power supply VHP.Next, both filaments l! , , After f132 is sufficiently heated, the normally closed contacts N and C are opened by the relay. At this time, if the induced voltage in the secondary winding W1 has a value sufficient to start the fluorescent lamp FL, the fluorescent lamp FL will be started instantaneously.

In this lighting state, the light amount of the fluorescent lamp FL by the photoelectric conversion elements P and D is fed back to the control circuit C0C,
It is also possible to obtain a constant amount of light by varying the impedance of the inductance elements L1 and Ll. Figure 2 shows a second embodiment of the present invention, which has the same functions as the components shown in Figure 1.・The same reference numerals are given and the explanations are omitted.0 Also, the basic operation is the same as that explained in relation to Fig. 1.・Trans LT,
This is the point. Also, LO is the leakage choker section of the leakage transformer.According to this, the shape of the variable impedance section L2 can be made small.0 [Effects of the Invention] As explained above, according to the present invention, When using a variable impedance ballast using a magnetic amplifier for dimming, when preheating the fluorescent lamp, short-circuit the non-power side terminal of the fluorescent lamp with a switch element, relay, etc., and adjust the impedance of the variable impedance ballast using the magnetic amplifier. By making it variable, it is possible to obtain a stable preheating current with a simple configuration.In addition, by monitoring the preheating current or f-i voltage using an observation resistor, etc., and feeding it back to the control circuit, The current value can be further stabilized.0 Furthermore, when a DC/AC exchanger with a self-excited oscillator is used as the high frequency power source instead of the high frequency power circuit, the impedance of the lighting circuit section may change during preheating. By exhibiting a nearly quadrature value regardless of the lighting state, there is less variation in the self-resonant frequency of the lighting circuit, which is advantageous in obtaining stable oscillation output.In particular, from the self-excited oscillator to the fluorescent lamp lighting circuit section. This advantage can be taken advantage of when outputs other than the output are extracted.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a high frequency fluorescent lamp lighting control device which is an embodiment of the present invention, Fig. 2 is a circuit diagram of a high frequency fluorescent lamp lighting control device which is a second embodiment of the invention, and Fig. 3 is a circuit diagram of a high frequency fluorescent lamp lighting control device which is an embodiment of the present invention. FIG. 4 is a diagram of a high-frequency fluorescent lamp lighting circuit having a conventional filament-dedicated winding. FIG. 4 is a diagram of a high-frequency fluorescent lamp lighting circuit having a filament transformer from a commercial wave power source. VHF...... High frequency power supply FL... Fluorescent lamps Ll, L2... Current limiting inductance elements fa, fb2... Filament K...・・・・・・・・・・・・Relay N, C...
・・・・・・Normally closed contact C0C・・・・・・Control circuit RM・・・・・・・Observation resistance L Tt・
・・・・・・・・・An uninvented embodiment of leakage transformer, f15 high frequency award front light lighting fence device 0 circuit diagram Figure 1 Accumulation of the present invention 21! Example) High-frequency firefly light lighting circuit diagram also has 3 high frequencies, which are specially designed for use in nest fiwomes! Hikaru Tobatake Light Track Map Figure 3

Claims (3)

[Claims] (1) A variable impedance stabilizer using a magnetic amplifier is interposed at least in part between the power source of a high frequency fluorescent lamp lighting device that uses a high frequency power source and the fluorescent lamp, and the high frequency light is controlled by variable impedance. A high-frequency fluorescent lamp characterized in that, in the fluorescent lamp lighting circuit, the impedance of the ballast is varied by a magnetic amplifier using a magnetic amplifier drive means, thereby making it possible to flow an appropriate filament current through the fluorescent lamp. Lighting control device. (2) When preheating the fluorescent lamp, the magnetic amplifier driving means shorts the non-power terminal side of the fluorescent lamp using a switch element, relay, etc., and changes the impedance of the variable impedance stabilizer using the magnetic amplifier to obtain an appropriate preheating current. A high-frequency fluorescent lamp lighting control device according to claim 1, characterized in that: (3) The magnetic amplifier driving means detects the filament voltage or filament current using an observation resistor and feeds it back to the control circuit, thereby adjusting the variable impedance value of the magnetic amplifier and controlling the voltage fluctuation of the high frequency power supply.
Alternatively, the high-frequency fluorescent lamp lighting control device according to claim 1, characterized in that it is configured to obtain a constant filament current regardless of frequency fluctuations.