JPS641759Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a fluorescent lamp circuit that ensures reliable starting of a fluorescent lamp that is lit in a dimmed state.

In general, fluorescent lamps differ from incandescent lamps in that when the phase is controlled (dimmer state), the preheating current is insufficient, or even if preheating is sufficient, a voltage higher than the starting voltage is not applied to the lamp. There are times when starting is not reliable. To prevent this, there are the following conventional methods.

(a) 100% lighting (not dimmed) at startup,
After lighting, use the manual switch to switch to dimming mode.

(b) Install a transformer to preheat the filament of fluorescent lamps to facilitate starting.

(c) Connect a dummy resistor in parallel with the dimming switching element to facilitate starting.

(d) Pulse lighting.

However, in (a) above, operation is troublesome and the type of switch must be changed depending on the installation location, which lacks versatility.In (b), one transformer must be installed for each light, which is costly. So, (c)
In (d), the loss of the dummy resistor increases, and in (d), the pulse voltage is applied without sufficient preheating, which may shorten the life of the lamp.In order to ensure sufficient preheating, (b) You may end up using a combination of methods.

The present invention eliminates the above-mentioned drawbacks of the conventional method.It adds a timer to the phase control type dimmer lighting circuit, turns on the timer circuit at startup, and adjusts the phase regardless of the phase angle determined by the constant of the phase control circuit. The feature is that the angle is set to zero, and furthermore, after a certain period of time has elapsed after lighting, the timer circuit is turned off, the phase angle is set to a phase angle determined by a constant of the phase control circuit, and the dimming state is switched. Furthermore, the transformer used to drive the phase control circuit is also used to drive the timer circuit and control the main thyristor using the auxiliary thyristor, thereby simplifying the configuration and reducing loss.

FIG. 1 shows an embodiment of the present invention. 1 is a commercial power supply, 2 is a filter yoke, 3 is a capacitor, 4
is a transformer, 5 is a full-wave rectifier that rectifies the output of the secondary coil N of the transformer 4, and 7 is a protective resistor that transmits the rectified pulsating current from the rectifier 5 to a power control circuit B to be described later. A diode 6 prevents a voltage supplied to a timer circuit 10 to be described later and smoothed by a Zener diode 8 and a capacitor 9 from being applied to the power control circuit B. 10 is a timer circuit, 11
13 is a capacitor that charges the rectified pulsating current supplied through the variable resistor 12 every cycle; 13 receives the divided voltage of resistors 16 and 17 at its gate terminal; This is a PUT that becomes conductive when the anode potential becomes higher than the gate potential. 15 is a pulse transformer driven by the signal from the cathode of PUT 13,
Generates a phase-controlled pulsed phase signal.
19 is a diode that allows this phase signal to flow in one direction. Among the above components, the full-wave rectifier 5, the protective resistor 7, the diode 6, the Zener diode 8, and the capacitor 9 constitute a DC circuit that converts the output of the secondary coil N into DC. Also, capacitor 11, variable resistor 12, PUT 13, resistor 14, pulse transformer 15, resistor 16, resistor 17, diode 19
constitutes a phase control circuit. Further, the transformer 4 and the DC circuit constitute a control power supply circuit A.

22 is a load including a fluorescent lamp and a ballast, and is driven by the commercial power supply 1. 20 is a main thyristor (bidirectional three-terminal thyristor) for dimming the fluorescent lamp, and 21 is an auxiliary thyristor (bidirectional three-terminal thyristor) that provides a trigger signal to the gate terminal of the main thyristor 20. The auxiliary thyristor 21 is driven by a pulsed signal from the pulse transformer 15, and the auxiliary output coil N22 provided in the transformer 4 supplies the thyristor 20 with a trigger signal that causes the thyristor 20 to have a latching current or higher.

Timer circuit 10 is shown in FIG. 23 is a charging resistor, 30 is a charging capacitor, 31 is a capacitor 3
32 is a transistor that is turned off when transistor 31 is turned on, and 33 is a transistor that is turned off when transistor 32 is turned off. 27,
28 is a resistor that divides the voltage at the terminal when the transistor 32 is ON, and applies this divided voltage to the emitter of the transistor 31 to
The base level at which the is turned on is set.

When the commercial power supply 1 is turned on and the DC circuit is driven, the timer circuit 10 is activated, but since the electric charge of the electrolytic capacitor 30 of this timer circuit is initially zero, the transistor 31 is cut off and does not operate, and the transistor 32 is turned on. Therefore, transistor 33
At the same time that the transistor 31 is turned on, a divided voltage determined by the resistors 27 and 28 is applied to the emitter of the transistor 31. When the transistor 33 is turned on, a starting signal as shown in FIG. 3b is generated from the OUT terminal of the timer circuit 10. This starting signal is applied to the gate of thyristor 21, so thyristor 21
is turned on, and at the same time, a trigger signal is applied to the gate of the thyristor 20 from the coil N22, and the thyristor 20 is turned on.
At this time, the auxiliary thyristor 21 and the main thyristor 2
The non-conduction angle of 0 becomes almost zero, resulting in almost 100% power output state. The load 22 is supplied with the same voltage shown in FIG. 3c as the commercial power supply shown in FIG. 3a, and is turned on at 100%. Therefore, the loaded fluorescent lamp will start reliably. At this time, pulse transformer 1
A phase-controlled pulse-like signal is generated from 5, but is ignored by the start signal.

Thereafter, when the charging of the capacitor 30 progresses and its potential exceeds the emitter potential of the transistor 31 + the base-emitter voltage VBE, the transistor 30
1 is turned on, the base potential of the transistor 32 becomes approximately equal to the emitter potential of the transistor 31, and the transistor 32 is turned on. Therefore, transistor 33 is turned off and generation of the start signal from timer circuit 10 is stopped.

Therefore, the signal applied to the gate of the thyristor 21 is only the pulsed phase signal from the pulse transformer 15. This phase signal is connected to the capacitor 11,
The signal is generated at a phase angle determined by the constants of the resistors 12, 16, and 17, resulting in a signal as shown in FIG. Therefore, the light of the load 22 is adjusted in a phase determined by the above constant.

The starting signal generation time from the timer circuit 10 is determined by the VBE of the resistors 23, 27, 28, the capacitor 30, and the transistor 31, but it may be a sufficient time for the load 22 to start and turn on steadily, for example, from 1 minute to All you have to do is choose as you like within 10 minutes.

In the above embodiment, since the starting signal from the timer circuit 10 is applied to the trigger input terminal of the phase modulation switch element for dimming, the circuit of the power control circuit B (the part surrounded by the broken line) does not need to be changed at all. It can be done without

As explained above, when the lighting circuit starts when the lighting circuit is in the dimming state, it automatically switches to the dimming state after lighting up to 100%, so there is no chance of starting errors. Start-up from a low temperature state can also be performed reliably. Furthermore, since the same transformer is used for three purposes: driving the phase control circuit, driving the timer circuit, and controlling the main thyristor, there is no waste and the configuration is simplified. Furthermore, since the voltage is converted to a suitable voltage for driving or control, subsequent power loss due to resistance, etc. is reduced.

[Brief explanation of the drawing]

Figure 1 is a circuit configuration diagram of the embodiment of the present invention, Figure 2 is a diagram of the timer circuit as well, Figure 3 is a signal waveform diagram of each part of Figure 1 in 100% lighting, and Figure 4 is a diagram of signal waveforms in dimmed lighting. FIG. 1 is a signal waveform diagram of each part. 1: AC power supply, A: power supply circuit, B: power control circuit, 10: timer circuit, 20: main switch element, 21: auxiliary switch element, 11 to 17: signal generation circuit.

Claims (1)

[Scope of utility model registration request] AC power supply, a transformer connected to the AC power supply, a DC circuit that converts the output of the secondary coil of the transformer to DC, a phase control circuit that is driven by the output of the DC circuit,
An auxiliary thyristor whose phase is controlled by a phase control circuit, a timer circuit that is driven by the output of the DC circuit and makes the non-conduction angle of the auxiliary thyristor almost zero for a while after AC power is turned on, and an auxiliary output coil provided in the transformer. A fluorescent lamp lighting circuit comprising: a main thyristor whose phase is controlled by receiving the output of an auxiliary output coil via the auxiliary thyristor; and a fluorescent lamp driven by an AC power source and whose light is dimmed by the main thyristor.