JP2001118690A - Lighting apparatus for emergency - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting apparatus for emergency which enables it to keep output voltage of lighting circuit as low as possible and to light cold cathode discharge lamp with certainty even in the dark. SOLUTION: The lighting apparatus for emergency is constructed by a lighting circuit 4 which operates through a battery B and a direct current power source E which is obtained by rectification and smoothing of a commercial power supply 3, cold cathode discharge lamps 1, 2 lighted by the lighting circuit 4, and a means of detecting electric power interruption 6 which judges the state of electric current of commercial power supply 3, and a switching circuit which switches the power supply for lighting circuit to either the direct power supply E when the commercial power supply 3 is live or the battery B when the commercial power supply is interrupted. A means of intermittent operation, which supplies power source to cold cathode discharge lamps 1, 2 intermittently in the case when lighting intensity of discharge lamp 1, 2 is extremely low under the influence of darkness in the neighbourhood, is settled in the lighting apparatus for emergency which retains a means of boosting 8 which supplies power source to lighting the circuit 4 at least by boosting the voltage of the battery B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an emergency lighting device provided with a circuit for lighting a cold cathode discharge lamp using a commercial power supply and a battery.

[0002]

2. Description of the Related Art Emergency illuminators for lighting a bulb or a discharge lamp in the event of a commercial power failure generally use a rechargeable secondary battery as a power source in the event of a power failure, and always charge this battery when the commercial power is turned on. In addition, it is equipped so that it can be turned on immediately in the event of a power failure. Of these emergency lighting devices, those with a built-in battery have a minimum necessary battery capacity to ensure an effective lighting time in order to reduce the size of the device, and the voltage is generally It is about several volts to several tens of volts.

When the light source at the time of a power failure is a light bulb, a simple circuit configuration for directly applying the battery voltage to the light bulb may be used. However, a discharge lamp does not light even when the battery voltage is applied as it is. In many cases, a so-called inverter circuit that converts a signal into a high-frequency voltage is used to obtain a high voltage that can be discharged. Among such discharge lamps, in the case of a cold cathode discharge lamp, since a filament for preheating does not exist, a dischargeable voltage is very high, and several hundred V to 1,000 V or more is required. Therefore, in order to obtain a high frequency voltage of several hundred volts from a battery voltage of several volts, the inverter circuit needs a boost ratio of 100 times or more.

In order to obtain such a step-up ratio, it is common to increase the turns ratio between the primary side and the secondary side by using a step-up transformer. Unless the wire diameter of the next winding is reduced, it becomes impossible to complete the winding, so that it is very difficult to secure the withstand voltage between the windings. In addition, in the case of an induction lamp that changes the optical output between when a commercial power supply is turned on and when a power failure occurs, the optical output is often changed by changing the input voltage to the step-up transformer. The output voltage is set on the basis of a small power failure, so when a commercial power supply with a large optical output is supplied, an excessive voltage is generated on the secondary side of the step-up transformer, and not only the insulation between the windings but also the insulator itself such as the bobbin is insulated. There is also the danger of destruction. Conversely, if the output voltage is set on the basis of the time when the commercial power is supplied, there is a possibility that the secondary voltage at the time of the power failure becomes insufficient and the discharge lamp does not light.

In a cold cathode discharge lamp, in a so-called dark state in which the illuminance in the vicinity of the discharge lamp is extremely low, there is a phenomenon that electrons in the discharge lamp are not sufficiently excited to be difficult to start. In order to solve this problem, there is a method of setting the output voltage to be higher so as to reliably light even in a dark state. However, a transformer having a very large withstand voltage performance is required. This leads to an increase in size and cost.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and makes it possible to suppress the output voltage of the lighting circuit as low as possible and to reliably light the cold cathode discharge lamp even in a dark state. It is an object of the present invention to provide a lighting device.

[0007]

In order to solve the above-mentioned problems, a DC power supply obtained by rectifying and smoothing a commercial power supply 3 as shown in FIG. E, battery B, DC power source E and battery B
, A cold cathode discharge lamp 1, 2 illuminated by the lighting circuit 4, a power failure detection means 6 for judging the energized state of the commercial power supply 3, An emergency lighting device comprising a switching circuit for switching the power of the lighting circuit 4 to the DC power source E and to the battery B at the time of a power failure, and having a boosting means 8 for boosting at least the voltage of the battery B and inputting the voltage to the lighting circuit 4 At
When the illuminance near the discharge lamps 1 and 2 is extremely low,
An intermittent operation means for intermittently operating the output to the cold cathode discharge lamps 1 and 2 is provided.

[0008]

(Embodiment 1) In order to solve the problem of high voltage generation in a step-up transformer as described above, for example, a rectified and smoothed DC A circuit that boosts the voltage of the internal battery to a voltage close to the voltage of the power supply is provided.This booster circuit operates during a power outage to reduce the difference between the DC voltage applied to the primary side of the transformer during energization and during a power outage. Then, there is an example in which an excessively high voltage is not continuously generated on the secondary side. In this example, if the boost voltage is controlled so that the current flowing through the discharge lamp (hereinafter referred to as “tube current”) becomes constant, the highest voltage is output when the discharge lamp is started during a power failure when the tube current is 0 mA. The booster circuit operates to generate a high voltage on the secondary side of the transformer and start the discharge lamp. However, since the tube current increases when the discharge lamp is turned on, the boosted voltage decreases instantaneously with the lighting of the discharge lamp, and the secondary voltage of the transformer also decreases. In this case, if a function for stopping the lighting circuit is added when the discharge lamp is not connected, the high voltage is not continuously generated on the secondary side of the transformer, and safety is ensured.

In order to solve the problem that the discharge lamp is hardly lit in a dark state, for example, Japanese Patent Application No. 9-345 is disclosed.
As in Japanese Patent No. 524, there is an example in which a lighting circuit is operated intermittently at a predetermined cycle and this intermittent operation is continued until the discharge lamp is turned on. If a high voltage is continuously applied in a dark state, the lighting circuit will overrun before the discharge lamp is lit, which may cause abnormal oscillation or abnormal heat generation.
By continuing the intermittent operation, the discharge lamp can be gradually excited while preventing the overrun of the lighting circuit, so that the discharge lamp can be turned on even in a dark state.
If the discharge lamp is excited for any reason during the intermittent operation (such as irradiation of external light or radio waves), this energy becomes a fire source and the discharge lamp is lit when a high voltage is applied from the lighting circuit. It will not be left in a point state.

The first embodiment is a combination of these two examples. FIG. 1 shows a configuration diagram of the present embodiment. A lighting circuit 4 that operates on both a DC power supply E obtained by rectifying and smoothing the commercial power supply 3 by a DC power supply circuit 9 and a battery B; cold cathode discharge lamps 1 and 2 that are lit by the lighting circuit 4; Detectors 11 and 12 for detecting the tube currents of the cathode discharge lamps 1 and 2; a lighting determination circuit 5 for determining the lighting state of the discharge lamps 1 and 2 based on the tube currents; It comprises a detection circuit 6, a charging circuit 7 for charging the battery B, and a booster circuit 8 for boosting the voltage of the battery B. In this configuration, the dark state determination process and the lighting determination process as shown in the flowcharts of FIGS. 2 and 3 of the present invention and the determination tables in Tables 1 and 2 are performed, and when the lighting determination circuit 5 determines that it is in the dark state. Causes the lighting circuit 4 to operate intermittently. With this configuration, even when the light output difference between the energized state and the power outage state is large and the battery voltage Vb is extremely low,
At the time of starting the discharge lamp at the time of power failure, a high voltage required for starting can be easily obtained, and at the time of stable lighting, the secondary voltage of the step-up transformer can be kept low. Further, even in a dark state, if the discharge lamp is excited by irradiation of external light or the like, the discharge lamp can be automatically turned on.

[0011]

[Table 1] Table 1 shows determination rules used in a dark state determination routine. In this example, when there are two cold cathode discharge lamps, if either one of the lamps 1 and 2 is normal, it is determined that the lamp is normal, and if both lamps are abnormal, it is determined that the lamp is in a dark state. .

[0012]

[Table 2] Table 2 shows a determination rule used in a lighting state determination routine. In this example, when there are two cold cathode discharge lamps, if both lamps 1 and 2 are normal, it is determined that the lighting state is normal, and if one of them is abnormal, the lighting state is non-lighting. Is determined.

The flowchart of FIG. 2 shows a process for determining the state of each lamp load prior to the determination of the dark state or the lighting state by the determination methods of Tables 1 and 2. With the lighting discrimination means stopped, the tube current value is compared with a reference value. If the tube current> reference value, the load value is set to 1 (normal), and if the tube current <reference value, the load value is set to 0.
(Abnormal). In order to obtain a stable load value, the number of times that the load value matches the previous value is counted by the counter i, and when the counter i becomes equal to or more than the predetermined value n, the load value becomes n times (for example, 4 times). Are all the same, the lighting state is determined, and the load values of the lamps 1 and 2 in Tables 1 and 2 are stored as the determined values. Also, the number of times each load value matches the previous value from the start of this processing is counted by the counter k, and if it exceeds m times (for example, 16 times), a reliable load value is obtained. , Table 1 and Table 2 are used to determine the dark state and the lighting state. If it is determined that the camera is in the dark state, a process of enabling a timer interrupt for performing an intermittent operation is performed to avoid the dark state.

The flow chart of FIG. 3 is a simplified version of the flow chart of FIG. 2, in which a load value is obtained by comparing a tube current with a reference value, and the number of times each load value matches the previous value is determined. Counting is performed by the counter i. When the counter i becomes equal to or more than the predetermined value n, if the load values of n times (for example, 16 times) are all the same value, the lighting state is determined and the lamps 1 and 2 of Table 1 and Table 2 are determined. The load value of 2 is stored as a fixed value. Here, according to Table 2, it is determined that the lighting mode is set when all of the lamps 1 and 2 are turned on, and that the lighting mode is turned off when at least one of the lamps is not turned on. The determination of the dark state is similarly performed according to the determination rules in Table 1.

In the intermittent operation in the dark state, only the lighting circuit may be operated intermittently, only the booster circuit may be operated intermittently, or both may be operated almost simultaneously. When only the booster circuit is operated intermittently, the output voltage of the lighting circuit when the booster circuit is stopped does not become 0, and the voltage is continuously applied to the discharge lamp. The electric lamp is excited earlier, and the transition to stable lighting can be made earlier. However, this is an effective means when commercial power is supplied to obtain a stable DC power supply, but if the primary consideration is to reduce battery consumption, at the time of a power failure, both the lighting circuit and the booster circuit are intermittently operated almost simultaneously. Is the most effective.

Table 3 shows an operation table of the lighting circuit and the booster circuit. In the dark state in the energized state, only the lighting circuit operates intermittently because there is no booster circuit. In a dark state in an emergency (at the time of power failure), the lighting circuit and the booster circuit may be stopped or may be operated intermittently. However, instead of stopping both, one of them is an intermittent operation. Further, when it is determined by the lighting determination process that there is no load, it is more likely that this state will continue for a long period of time, so it is safer to stop both the lighting circuit and the booster circuit. The lighting circuit is always operated in a normal state without a no-load condition, and the booster circuit is operated only in an emergency (at the time of power failure).

[Table 3]

(Embodiment 2) FIG. 4 shows Embodiment 2 of the present invention.
Is shown. In the present embodiment, the DC power supply E (capacitor) that not only boosts the voltage of the battery B by operating the booster circuit 8 during a power failure but also rectifies and smoothes the commercial power supply 3 by the rectifying and smoothing circuit 91 and reduces the voltage by the step-down circuit 92 This is an example in which the voltage (C voltage) is also increased. By operating the booster circuit 8 both when the commercial power supply 3 is energized and during a power failure,
If control is performed so that the tube currents of the discharge lamps 1 and 2 become constant, the light output during power-on and during power outage can be set arbitrarily and easily. Further, even if the DC power supply voltage or the voltage of the battery B fluctuates, the booster circuit 8 can cope with a wide range of voltages.
If so, the degree of freedom in designing the voltage of the DC power supply E and the battery B is increased, and a common design can be easily made for a wide range of products. In such a configuration, when the lighting determination circuit 5 determines that the lighting state is dark, the lighting circuit 4 and the booster circuit 8 are operated intermittently. By doing so, similarly to the first embodiment, it is possible to reliably turn on the discharge lamps 1 and 2 even in a dark state while keeping the secondary voltage of the step-up transformer low.

In the case of the present embodiment, the booster circuit 8 may be operated at all times during energization or during a power failure. However, in order to save power and reduce battery consumption when the commercial power supply is energized, a lighting circuit is required. At the same time, intermittent operation is most effective. Table 4 shows an operation table of the lighting circuit and the booster circuit at the time of energization and power failure, and Table 5 shows a list of combinations of operations at the time of darkness. Any combination of (a), (b), and (c) in Table 5 is used as the dark operation in Table 4. As shown in Table 5, in the dark, both the lighting circuit 4 and the booster circuit 8 operate intermittently, or one of them operates intermittently and the other operates continuously. If the loss in the booster circuit 8 is negligible, a method in which the booster circuit 8 is continuously operated to constantly obtain a stable DC voltage and only the lighting circuit 4 is intermittently operated as shown in FIG. However, the control circuit can be simplified, and the cost can be reduced. When it is determined that there is no load, it is safer to stop both the lighting circuit 4 and the booster circuit 8 as in the first embodiment. When the load is not in a normal state and the load circuit is normal, both the lighting circuit 4 and the booster circuit 8 are operated continuously.

[0019]

[Table 4]

[Table 5] Further, in the first and second embodiments, an example is described in which the booster circuit is controlled so that the tube current becomes constant. However, the control may be performed such that the output voltage of the booster circuit 8 becomes constant as shown in FIG. Absent. However, this is effective when there is no large difference between the optical output (lighting circuit input voltage) when the commercial power supply is turned on and when there is a power outage. You have to be careful.

(Embodiment 3) This embodiment is an example of an emergency lighting device having boosting means for boosting at least the voltage of a battery and inputting the boosted voltage to a lighting circuit, in which deterioration of the battery is reduced. As shown in the first embodiment, only the voltage of the battery is boosted and input to the lighting circuit. In an emergency lighting device having a booster for boosting the voltage of a battery and inputting it to a lighting circuit, for example, when boosting the voltage of the battery, when the discharge lamp is lit by the battery at the time of a power failure, the voltage boosted by the booster is Input to the lighting circuit. In general, the boosting means is controlled so that the tube current becomes constant as shown in FIG. 4, or the boosting voltage is made constant as shown in FIG.

If the boosting means is not provided, the input voltage to the lighting circuit gradually decreases as the battery discharges, and as shown in FIG.
As the battery current decreases, the tube current decreases, and the discharge current from the battery also decreases. However, if there is a booster circuit, the battery current and the boosted voltage are kept constant even when the battery voltage Vb is reduced. Therefore, as shown by the dotted line in FIG. The current does not decrease, but rather the discharge current increases. The self-heating due to the large current discharge also increases, and a very large stress is applied to the battery. This is one of the causes that accelerates the deterioration of the battery, and may lead to a short life.

Therefore, at least the battery voltage Vb
In an emergency lighting device having a boosting means for boosting the voltage and inputting it to the lighting circuit, means for changing the setting of the tube current and the boosted voltage in accordance with the decrease of the battery voltage Vb is provided. For example, as shown by a solid line in FIG. 7, when there is a battery voltage Vb equal to or higher than the reference voltage V1, a predetermined tube current I1 that ensures a constant light output as the lighting device is obtained, and When the voltage Vb decreases and becomes equal to or lower than the reference voltage V1, the tube current becomes I2 (≦ I
1). When the battery voltage Vb further decreases and reaches the limit point V2 for preventing the deep discharge of the battery, the lighting circuit is stopped to protect the battery. By performing such control, deterioration due to large current discharge or deep discharge at the end of discharge when the voltage Vb of the battery is low can be reduced, and the life of the battery can be extended.

If the charge and discharge are repeated in a region where the voltage does not fall below the limit point V2, which is generally called an overdischarge prevention voltage, the original life performance can be exhibited. By suppressing self-heating of the battery due to a large current discharge in a low voltage state, the service life can be further extended. Further, the time until the battery voltage Vb becomes equal to or lower than the reference voltage V1 and stops at the limit point V2 can be lengthened, so that the lighting time until the discharge lamp extinguishes can be further lengthened. In the event of a power outage or emergency, even a little light can give a sense of security, so extending the time until the extinction is an effective means even if a predetermined light output is not obtained.

Although FIG. 7 shows an example in which the tube current is set in two stages of I1 and I2, a plurality of levels may be set between I1 and I2, or the tube current may be set continuously. The same effect can be obtained if the discharge current at the end of discharge can be suppressed lower.

[0025]

According to the present invention, in an emergency lighting device having a boosting means for lighting a cold cathode discharge lamp with a commercial power supply and a battery and boosting at least the voltage of the battery and inputting the boosted voltage to a lighting circuit, The output voltage can be kept as low as possible, and the cold cathode discharge lamp can be reliably turned on even in a dark state. Further, by controlling the boosting means so as to suppress the discharge current at the end of discharging of the battery, it is possible to extend the life of the battery. In recent years, a low voltage of several volts or less has been commonly used as a battery voltage of an emergency lighting device, and the present invention is a particularly effective technique when such a low voltage battery is used.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing a configuration of Embodiment 1 of the present invention.

FIG. 2 is a flowchart illustrating an example of a load state detection operation according to the first embodiment of the present invention.

FIG. 3 is a flowchart illustrating another example of the load state detection operation according to the first embodiment of the present invention.

FIG. 4 is a block circuit diagram showing a configuration according to a second embodiment of the present invention.

FIG. 5 is a block circuit diagram showing a configuration of a modification of the second embodiment of the present invention.

FIG. 6 is an explanatory diagram illustrating an operation at the time of battery discharge according to a third embodiment of the present invention.

FIG. 7 is an explanatory diagram showing an operation when a tube current is reduced at the time of battery discharge in Embodiment 3 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cold cathode discharge lamp 2 Cold cathode discharge lamp 3 Commercial AC power supply 4 Lighting circuit 5 Lighting discrimination circuit 6 Power failure detection circuit 7 Charging circuit 8 Boosting circuit 9 DC power supply circuit

Claims (14)

[Claims] 1. A DC power supply obtained by rectifying and smoothing a commercial power supply, a battery, a common lighting circuit operated by the DC power supply and the battery, a cold cathode discharge lamp lit by the lighting circuit, A power failure detection means for determining a power supply state; and a switching circuit for switching a power supply of a lighting circuit to the battery when the commercial power supply is turned on. In an emergency lighting device having a boosting means for inputting to a lighting circuit, an intermittent operation means for intermittently operating an output to the cold cathode discharge lamp is provided when an illuminance near the discharge lamp is extremely low in a dark state. An emergency lighting device, characterized in that: 2. The emergency lighting device according to claim 1, wherein the boosting means is means for boosting only the voltage of the battery. 3. The emergency lighting device according to claim 1, wherein said boosting means is means for boosting both a battery voltage and a DC power supply. 4. The emergency lighting device according to claim 1, wherein said intermittent operation means is means for intermittently operating a switching element of said lighting circuit. 5. The emergency lighting device according to claim 1, wherein the intermittent operation means is means for intermittently operating the boosting means. 6. The emergency lighting device according to claim 1, wherein said intermittent operation means is means for intermittently operating a switching element and a boosting means of said lighting circuit at substantially the same time. apparatus. 7. The battery according to claim 1, wherein when the voltage of the battery is lower than a reference voltage that guarantees an optical output at the time of a power failure, the discharge current of the battery is smaller than that when the voltage is higher than the reference voltage. 7. The emergency lighting device according to any one of 6. 8. The emergency illuminating device according to claim 1, further comprising a plurality of cold cathode discharge lamps, wherein when all the cold cathode discharge lamps are turned off, it is determined to be in a dark state. 9. A system for monitoring a voltage of a battery at the time of a power failure, comprising: a unit for controlling a booster circuit so that a discharge current of the battery is reduced when the voltage of the battery falls below a first level. The emergency lighting device according to claim 1, wherein 10. The emergency lighting device according to claim 9, further comprising means for stopping discharge of the battery when the voltage of the battery falls below the second level. 11. A step-up circuit for controlling a boosting circuit such that a discharge current of a battery continuously decreases as a voltage of the battery decreases from a first level to a second level. The emergency lighting device as described. 12. The apparatus according to claim 10, further comprising means for controlling the booster circuit so that the discharge current of the battery decreases stepwise as the voltage of the battery decreases from the first level to the second level. The emergency lighting device as described. 13. The boosting means according to claim 1, further comprising means for monitoring an input voltage of the lighting circuit, wherein the boosting ratio is controlled so that the input voltage of the lighting circuit becomes a predetermined level regardless of the voltage of the battery. An emergency lighting device, characterized in that: 14. The apparatus according to claim 1, further comprising means for detecting a no-load state in which the discharge lamp is not connected, and when it is determined that no load is present, both the boosting means and the lighting means are stopped. Emergency lighting equipment.