JPH0330279B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a discharge lamp lighting device.

FIG. 1 shows a circuit diagram of a discharge lamp lighting device using a conventional pulse-start type discharge lamp. In this circuit, when an AC power source 1 is turned on, a pulse generator 2 operates and a high pulse voltage is applied to an inductance element. The pulse voltage is generated at both ends of the ballast Ch consisting of a barrel chiyoke coil, and this pulse voltage is applied to both ends of the discharge lamp 3 to start and light the discharge lamp 3. Also, when the discharge lamp 3 is turned on, the circuit is activated. When a lamp current la flows through the circuit, a detection section 4 inserted in series in the circuit detects this lamp current la and stops the operation of the pulse generation section 2. Furthermore, in such a conventional device, when the discharge lamp 3 goes out due to a sudden change in the AC power source 1, the pulse generator 2 operates again due to the lamp current la = 0, and a pulse voltage is applied to both ends of the discharge lamp 3, causing the discharge lamp to emit light. It is now possible to restart electric light 3. However, in such a conventional device, when the AC power source 1 is applied with the discharge lamp 3 removed, a high pulse voltage generated by the operation of the pulse generator 2 is constantly generated at both ends of the ballast Ch. , there is a fear that the insulation deterioration of the ballast Ch will accelerate. Therefore, it is necessary to improve insulation performance to counter this, resulting in increased costs and
The drawback was that it inevitably became larger. In addition, in the above-mentioned condition, a high voltage pulse voltage is constantly generated on the secondary side of the ballast Ch, so the electric wire used is required to have the ability to withstand high voltage pulses, and from this point as well, an increase in costs is unavoidable.

Furthermore, it has the disadvantage that it cannot be used in places where there is a risk of human contact due to the generation of pulsed voltage, as it is extremely dangerous.

The present invention has been made in view of the above-mentioned drawbacks, and its purpose is to ensure that the discharge lamp is not lit under no load when the discharge lamp is not connected, or when the discharge lamp does not light up for some reason (tube breakage, electrode failure, etc.). To provide a discharge lamp lighting device which prevents the life of the device from being shortened due to insulation deterioration etc. by preventing high voltage pulse voltage from being applied to the ballast for a long period of time when the device is stopped.
The present invention will be explained below with reference to Examples.

FIG. 2 shows a circuit block diagram of an embodiment of the present invention. In the figure, 5 is a timer section, and this timer section 5 has a detecting section 4 and a detecting circuit 6, which are similar to those using the conventional example. It operates for a limited time at the same time as the AC power supply 1 is turned on, and when the inverted signal A2 of the detection signal _A1 from the detection unit 4 is not input by the time-up time, a pulse is sent to the pulse generation unit ₂ at the time-up time. It is designed to output a stop signal _a3 .

That is, the pulse generator 2 outputs a detection signal _a1 which is a lighting output when the detector 4 detects that the discharge lamp 3 is normally lit, or the discharge lamp 3 is turned on for a certain period of time after the AC power supply 1 is turned on. The timer section 5 occurs when the detection signal _a1 is not output from the detection section 2 in the lighting state.
It is equipped with a stop means that stops its operation in response to one of the pulse stop signals a ₃ and sets a state in which the discharge lamp 3 is not connected. It has a function to prevent insulation deterioration such as Ch.

Figure 3 shows a time chart of the circuit in Figure 2,
Figure a shows the on/off of the AC power supply 1, Figure b shows the flow of the lamp current la, Figure c shows the detection signal _a1 output from the detector 4 to the pulse generator 2, Figure d shows the detection block 4. The detection signal a ₁ is the inverted signal a ₂ of the timer section 5.
The signal e in the same figure is the pulse stop signal a ₃ , and the signal f in the same figure is the signal output to the ballast Ch by the operation of the pulse generator 2.
The generation states of the pulse voltages generated at both ends are shown, respectively. Time t ₀ to _{t 4} is a time chart when the discharge lamp 3 is not lit, and after time t ₅ is a time chart when the discharge lamp 3 is normally lit. show.

However, when the AC power supply 1 is turned on at time t ₁ , the pulse generator 2 operates and a pulse voltage is generated across the ballast Ch, and a pulse voltage is also generated on the secondary side, satisfying the starting conditions for the discharge lamp 3. let By the way, if the discharge lamp 3 is not lit even at time _t2 due to a tube breakage or the like, the detection signal _a1 of the detection unit 4 is not generated.
On the other hand, the timer unit 5, which started its time-limited operation when the AC power supply 1 was turned on, receives an inverted signal _a2 from the detection unit 4, which is “H”.
level, it is not reset and continues to operate for a limited time. When the timer section 4 times up at time _t3 , a pulse stop signal _a3 is generated from the timer section 4, and the pulse generating section 2 stops its operation. Therefore, no high-voltage pulse voltage is generated across the ballast Ch, and no pulse voltage that exceeds the maximum time (time set by the timer section 5) T occurs.

By the way, when the discharge lamp 3 is normal, when the AC power supply 1 is turned on at time _t5 , the pulse voltage generated across the ballast Ch due to the operation of the pulse generator 2 is applied to both ends of the discharge lamp 3. The discharge lamp 3 is turned on at time _t6 . When the discharge lamp 3 is lit, a lamp current Ila flows through the circuit, and the detection unit 4 detects this lamp current Ila, detects that the discharge lamp 3 is lit normally, and outputs a detection signal _a1 . This detection signal _a1 is input to the pulse generator 2 to stop the operation of the pulse generator 2, and at the same time is input to the timer unit 5 as an "L" level inverted signal _a2 to set the count _T1 of the timer unit 5. Reset. If the discharge lamp 3 is normal, even if it goes out, a pulse voltage will be generated for the time T, so the discharge lamp 3 can be turned on again. In the case of a load condition, the timer section 5 can only be reset by turning off the AC power supply 1 or manually resetting it, which prevents electric shock accidents caused by high pulse voltage and ensures a high level of safety. be.

FIG. 4 shows a practical circuit of the embodiment shown in FIG.
The light emitting diodes LED ₁ and LED ₂ are made to emit light, and optical detection signals a ₁ are outputted to the CdS element 7 provided in the optically coupled pulse generation section 2 and the CdS element 8 provided in the timer section 5, respectively. ing. The pulse generator 2 has the CdS element 7 connected in parallel to the time constant capacitor _C1 of the trigger circuit of the triax Ts, and when the optical detection signal _a1 is not input, the CdS element 7 has a high resistance value. , the trigger circuit is enabled, and when the optical detection signal _a1 is input,
The CdS element 7 has a low resistance value and stops charging the capacitor _C1 , thereby stopping the operation of the trigger circuit. In other words, when the discharge lamp 3 is turned on,
The CdS element 7 constitutes a stopping means.

On the other hand, the timer section 5 has a CdS element 8 connected in series to the reset terminal of the timer element IC, and when the optical detection signal _a1 is not input, the high resistance value of the CdS element 8 prevents input of the reset signal.
Conversely, when the optical detection signal _a1 is input, the CdS element 8
A reset signal can be input due to the low resistance value of
Ry was activated and inserted in series to pulse generator 2.
The operation of the pulse generator 2 is stopped by opening the NC type relay contact r and cutting off the power to the pulse generator 2.

In other words, in the state until the reset signal is input, the timer circuit 5 charges the capacitor C ₀ via the time constant resistor R ₀ when the power is turned on, and when this charging voltage reaches a certain level, the timer element IC When it is turned on, that is, when the time has elapsed, the output turns on the transistor Q, operates the relay Ry, and turns off the relay contact r.
The signal for operating Ry becomes a pulse operation stop signal, and its relay contact r constitutes a stop means for the pulse generator 2.

The present invention provides an AC power supply, a pulse-start discharge lamp connected to the AC power supply via a ballast made of an inductance element, and a pulse-start discharge lamp connected to both ends of the pulse-start discharge lamp via an intermediate tap of the ballast. A pulse generating section that starts and lights up the discharge lamp by applying an electric current, a detecting section that detects the lighting state of the discharge lamp, and a timer section that starts a timing operation in response to the non-lighting output of this detecting section and generates a pulse stop signal after a predetermined period of time. a means for enabling the timer unit to operate for a predetermined period of time when the discharge lamp transitions from a non-lighting state to a lighting state and reaches the next non-lighting state; and a lighting output of the detection unit. and a stop means for stopping only the operation of the pulse generating section when receiving a pulse stop signal from the timer section or when receiving a pulse stop signal from the timer section.
If the discharge lamp is operating normally or has not been lit for a certain period of time, the discharge lamp lighting device can be released from the abnormal condition without turning off the input power to the ballast, and only the operation of the pulse generator is stopped, so it is stable. This method does not require a large-capacity switch element, which is required when cutting off the input power to the device, and therefore costs can be reduced. In addition, by using a small, small-capacity switch element, the discharge lamp lighting device can be made more compact. Moreover, since high-voltage pulse voltage does not occur abnormally for a certain period of time when there is no load or when there is a malfunction such as damage to the discharge lamp, there is less risk of electric shock accidents, etc., and moreover, unnecessarily high pulse voltage is applied to the ballast. This eliminates the need to set the insulation performance of the ballast higher than normal performance, which avoids increased costs and equipment size, and also has special insulation performance for the electric wire used on the secondary side of the ballast. Because it does not require the use of external wires, the cost is low and it is highly marketable. Furthermore, since the secondary wires and ballasts are not exposed to pulse voltage for long periods of time, there is almost no insulation deterioration and the service life is long. This has the effect of preventing shortening of the lifespan. In addition, as mentioned above, since only the operation of the pulse generator is stopped, voltage is generated at the output terminal even after detecting that the discharge lamp is not lit. By connecting a lamp such as an incandescent lamp and detecting the current flowing through the connection point, it is possible to check whether the discharge lamp has reached its lifespan, whether there is a malfunction in the lighting device, or even whether there is a malfunction in the pulse generator. If you replace an unlit discharge lamp with another lamp that does not require a generator, you can immediately turn on the lamp without having to turn off the power and then turn it on again. Therefore, it can be used in places where illumination is essential, such as when machinery is in operation. This has the effect of ensuring the safety of workers by quickly obtaining alternative light without any loss time in factories that use the system. In addition, since it is not configured to cut off the original power supply, only the discharge lamps where the pulse generator has stopped operating will go out.
Only the unlit discharge lamp can be replaced with the above lamp without having to turn off other discharge lamps.Furthermore, the circuit configuration is simple because one detection unit can detect both the unlit and lit states. In addition, the structure can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional example, FIG. 2 is a circuit block diagram of an embodiment of the present invention, FIG. 3 is a time chart of each part of the same, and FIG. 4 is a specific circuit diagram of the same. AC power supply, 2 is a pulse generator, 3 is a discharge lamp, 6 is a detection circuit, and Ch is a ballast.

Claims (1)

[Claims] 1. An AC power supply, a pulse-start discharge lamp connected to the AC power supply via a ballast made of an inductance element, and taps provided at predetermined positions on the ballast at both ends of the pulse-start discharge lamp. There is a pulse generator that applies a pulse voltage to start and turn on the discharge lamp, a detector that detects the lighting state of the discharge lamp, and a timer that starts timing operation in response to the non-lighting output of this detector and stops the pulse after a predetermined period of time. a timer unit that generates a signal; and means for enabling the timer unit to perform a timing operation for a predetermined period when the discharge lamp transitions from an unlit state to a lit state and reaches the next unlit state when the discharge lamp is not lit; A discharge lamp lighting device comprising: a stop means for stopping only the operation of the pulse generating section when receiving a lighting output from the detecting section or when receiving a pulse stop signal from the timer section.