JPH0898434A - Illuminator - Google Patents

Abstract

PURPOSE: To obtain an illuminator in which an auxiliary power supply can be charged regardless of fluctuation in the AC power supply voltage and power interruption can be detected instantaneously. CONSTITUTION: A comparator CO1 compares the voltage V2 across a capacitor C1 with a reference voltage V3 obtained by dividing the voltage VCH across a smoothing capacitor CH by means of Zener diodes ZD1 , ZD2 and resistors R21 , R21 , R23 . An output from the comparator CO1 is fed to the set (S) terminal of an RS flip-flop 2 and the voltage VCH across the smoothing capacitor CH is applied to the reset (R) terminal of the RS flip-flop 2 having '-Q' terminal delivering an output for controlling a switching element Q1 . The voltage V10 across a resistor R26 is employed for controlling a switching element Q6 . This constitution realizes an illuminator in which an auxiliary power supply can be charged regardless of fluctuation in the power supply voltage and power interruption can be detected instantaneously.

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 lighting a lighting load, and more particularly to an emergency power supply for the lighting device and a power failure detection circuit.

[0002]

2. Description of the Related Art Conventionally, in lighting devices, there is a method of controlling the phase of the charging current to a capacitor, which is a constant current with respect to a voltage fluctuation of an AC power source, for charging a capacitor serving as an emergency power source. An example of the circuit is shown in FIG. (First Conventional Example) AC power supply V _ac is stepped down by a down transformer T to rectify DB
In the full-wave rectified pulsating voltage V _1, the rectifier switching element Q ₂ from the positive terminal of DB, diode - the difference voltage between the series-connected power BATT through the de D _2, switching element Q _2, diodes - de D _2, power BATT, through a resistor R ₅ to the power supply of the emergency to charge the capacitor C _1.

The phase control of the charging current I for charging the capacitor C ₁ is performed by the switching element Q ₂ , and the switching element Q ₂ is controlled between the base of the switching element Q ₂ and the ground via the resistor R _8. This is performed by the connected switching element Q ₁ . Resistors R _1, R ₂ and the reference voltage V _3H obtained by dividing the external power source Vref min, the capacitor C ₁ of the voltage across V _2, the resistance R ₃ is connected to both ends of the resistor R ₂ via the switching elements Q ₃ When is off,
The comparator CO ₁ compares and outputs the result to the NOT gate (N ₁ )
The switching element Q ₁ is controlled by inputting it to the base of the switching element Q ₁ via.

When the switching element Q ₃ is on, the reference voltage V _{3L obtained by} dividing the external power supply Vref by the resistors R ₁ and R ₃ and the voltage V ₂ across the capacitor C ₁ are compared. By switching the output of CO ₁ and inputting it to the base of the switching element Q ₁ , the switching element Q
Control ₁ Here, if R ₂ > R ₃ ... (1), then V _3H > V _3L・ ・ ・ ・ ・ ・ (2)

[0005] The switching element Q ₃ of base - the scan terminal is connected to the output terminal of the comparator CO _1, and controls the switching element Q ₃ by an output of the comparator CO _1, the switching element Q ₂ base - scan & A resistor R ₇ is connected between the emitters, a resistor R ₆ is connected to both ends of the capacitor C ₁ , and a resistor R ₄ is connected to both ends of a series circuit of the resistors R ₅ and R ₆ .

Next, the operation will be briefly described with reference to FIG.
It First, switching element Q₃Is turned on
Sensor C₁Voltage V across₂Is the reference voltage V_3LGet lower
And the comparator CO₁Outputs a low (L) level signal,
Switching element Q₃Is turned off. Switching element
Q₃Is turned off, the reference voltage V₃Is V_3LTo V_3HChange to
To do. Also, the NOT gate (N₁) Via H level
Switching element Q to which a signal is input₁Turns on. Su
Itching element Q₁Is turned on, switching element Q₂
Of the switching element Q₂Is
Turned on. In this case, the pulsating voltage V₁Power source BATT
If it is too low, the charging current I will not flow, so the capacitor C₁
Is not charged. Ripple voltage V₁Is higher than the power supply BATT
Then the charging current I changes to the switching element Q.₂， Dio
-D₂, Power supply BATT, resistance R_FiveFlowing through
Densa C₁Is charged and the capacitor C₁And resistance R_FiveAnd with
Capacitor C depends on the time constant₁Voltage V across ₂Is
Going up.

When the voltage V ₂ across the capacitor C ₁ exceeds the reference voltage V _3H , the comparator CO ₁ outputs an H level signal, the switching element Q ₃ is turned on, and the reference voltage V _{3 changes} from V _3H to V _3. Change to _3L . In addition, NOT gate (N ₁ )
Since the switching element Q ₁ to which an L level signal is input via is turned off, the switching element Q ₂ is also turned off and the charging current I does not flow. In this case, the capacitor C ₁
The resistor R _4, R _5, is discharged through a R _6, across the voltage V ₂ of capacitor C ₁ by a time constant determined by the capacitor C ₁ and a resistor R _4, R _5, R ₆ are decreases. By repeating the above operation, the capacitor C ₁ is charged and discharged, and the charging current I is controlled. The portion indicated by the hatched portion A in FIG. 9 indicates the portion where the charging current I is flowing. Here, by changing the reference voltage V _3H , the area of the shaded area A changes, so that the charging current I can be changed.

However, even if the reference voltage V _3H is constant, if the AC power supply V _ac changes as shown in FIG. 10, the area of the shaded area A changes, so that the charging current I changes. That is, the first problem occurs that the charging current I rises when the AC power supply V _ac drops.

To solve the first problem, the AC power supply V _ac
In order to keep the area of the shaded area A substantially constant even if
As shown in the circuit diagram of FIG. ₂ , the contact B between the resistors R ₁ and R ₂ and the cathode terminal of the diode D ₁ are connected by the resistor R ₉ so that the reference voltage V _3H changes with the fluctuation of the AC power supply V _ac . In addition, by changing it as shown in FIG. 13, as shown in FIG.
_{Even if ac} changes, the shaded area A can be made substantially constant. (Second Conventional Example) However, if the AC power supply V _ac drops too much, the charging current I will always flow as shown in FIG. In other words, there is a second problem that the charging current I cannot be controlled for a large fluctuation of the AC power supply V _ac .

To solve the second problem, the AC power supply V _ac
Is less than a substantially constant value, there is a method of stopping the charging of the capacitor C _{1 by} setting the reference voltage V ₃ to 0 V, and its circuit example is shown in FIG. (Third Conventional Example) The difference from the circuit of the second conventional example shown in FIG.
_{When a} switching element Q ₄ is connected in parallel to both ends of ₂ and the AC power supply V _ac is below a substantially constant value, the voltage V _CH across the smoothing capacitor CH is _divided by resistors R ₁₀ and R ₁₁ to obtain a voltage V
₄ and the external power supply V _T by the comparator CO ₂ comparing and outputting the high (H) level signal to turn on the switching element Q ₄ and turn off the switching elements Q ₁ and Q _2, thereby charging current. I is stopped, and the same configurations as those of the second conventional example are denoted by the same reference numerals, and the description thereof will be omitted. The capacitor C ₂ connected in parallel with the resistor R ₁₁ is a capacitor for removing noise, and the relationship between the reference voltage V _3H and the pulsating current voltage V ₁ is as shown in FIG.

Conventionally, as a method of detecting a power failure in a power supply circuit of a lighting device, there is a method of detecting a voltage V _CH across a smoothing capacitor CH, and an example of the circuit is shown in FIG. (Fourth conventional example) AC power supply V _ac is stepped down by down transformer T and rectifier DB
The voltage V _CH obtained by smoothing the full-wave rectified pulsating current voltage V ₁ with the smoothing capacitor CH is connected via the diode D ₁ to the resistor R ₁₀ ,
The voltage across V ₄ of the resistor R _11, which was pressurized with R ₁₁ min, the reference voltage V
_The comparator CO ₃ compares and outputs _S with the voltage V ₄ across the resistor R ₁₁ to fall below the reference voltage V _S , thereby detecting a power failure and obtaining an H level power failure detection signal S ₂ . When the H level power failure detection signal S ₂ is input to the control circuit 1, the control circuit 1
Switches to the emergency lighting state. The capacitor C ₂ connected in parallel with the resistor R ₁₁ is a noise removing capacitor.

However, in the fourth conventional example, the smooth
Capacitor CH, capacitor C₂, Resistance R_Ten, R₁₁Decided with
Due to the whole time constant, the resistance R as shown in FIG.₁₁Both ends of
Pressure V _FourIs the reference voltage V_SIt takes time to fall below (example
For example, time t when there is no load₀Requires. ) So the power outage is instantaneous
Cannot be detected. AC power supply V_acDetection of peak value drop
If the ambient temperature rises abnormally,
Cannot be switched to the emergency lighting state and become unlit.
And the fluctuation of the secondary voltage of the down transformer T
If the value is large, the detection level of power failure will vary.
The third problem arises.

As a method for solving the above-mentioned third problem,
There is a detector for detecting the peak voltage of the pulsating current voltage V _1. An example of the circuit is shown in FIG. (Fifth Conventional Example) A voltage V _{5 obtained by} dividing the pulsating current voltage V ₁ by resistors R ₁₅ and R ₁₆ ,
A voltage V _{6 obtained by} dividing the external power supply Vref by resistors R ₁₇ and R _18.
Is compared with the comparator CO ₄ , and the power failure is detected when the voltage V ₅ falls below the voltage V ₆ . When a power failure is detected, the comparator CO ₄ sends the L level signal S ₃ to the switching element Q.
₇ of base - by entering the scan, turns off the switching element Q _7. When the switching element Q ₇ is turned off, the external power source Vr
ef through a constant current source charging current I _DC to a capacitor C ₃
Are charged, and the voltage V _C3 across the capacitor C ₃ becomes the time t ₁
When the voltage rises gradually and exceeds the reference voltage V ₇ , the comparator CO ₅ inputs the H level power failure detection signal S ₂ to the control circuit 1. When the H level power failure detection signal S ₂ is input to the control circuit 1, the control circuit 1 is switched to the emergency lighting state.

With such a configuration, the power failure can be detected within the time t ₁ , so that the time required for the power failure detection can be shortened. (Figure 20)

[0015]

However, in the third conventional example, if the secondary voltage of the down transformer T fluctuates greatly, the following fourth problem will occur.

First, when the switching element Q ₄ is turned on and the charging current I is stopped due to the decrease in the AC power supply V _ac , the impedance on the load side rises, and therefore the down transformer T.
Secondary voltage rises, that is, the voltage V _CH across the smoothing capacitor CH rises. Voltage V _CH across smoothing capacitor _CH
Rises and exceeds the external power supply V _T , the switching element Q ₄ turns on again and the charging current I flows. When the charging current I flows, the impedance on the load side decreases, and the secondary voltage of the down transformer T decreases, that is, the smoothing capacitor CH.
The voltage V _CH across the two ends of the voltage drops. When the voltage V _CH across the smoothing capacitor CH drops and falls below the external power supply V _T , the switching element Q ₄ turns off again and the charging current I stops. As described above, the fourth problem arises that the charging current I is stopped and flows repeatedly due to the secondary voltage fluctuation of the down transformer T.

In the fifth conventional example, if the peak voltage value of the pulsating current voltage V ₁ fluctuates due to a change in impedance on the load side, accurate power failure detection becomes impossible. The fifth problem arises.

The present invention has been made in view of the above problems, and an object of the present invention is to charge an auxiliary power supply without depending on a voltage fluctuation of an AC power supply, and to have an instantaneous power failure. It is to provide an illuminating device capable of detecting the.

[0019]

In order to solve the above problems, according to the invention as set forth in claim 1, it normally operates with an AC power supply, and operates with an auxiliary power supply when the peak value of the AC power supply decreases. In addition to lighting the lighting load, a capacitor that serves as an auxiliary power source, a charging control unit that charges and discharges the capacitor, and a power failure detection unit that detects whether the lighting load is turned off. , When the AC power supply is near the rated value, the charging current of the capacitor is made almost constant against the voltage fluctuation of the AC power supply, and when the AC power supply becomes gradually smaller than the rated value, the value of the charging current is gradually decreased. Characterize.

According to the second aspect of the present invention, it is normally operated by an AC power supply, and when the peak value of the AC power supply is lowered, it is operated by an auxiliary power supply to light the lighting load, and a capacitor serving as an auxiliary power supply. In a lighting device including at least a charge control unit that charges and discharges a capacitor and a power failure detection unit that detects whether or not the lighting load is turned off, the charge control unit is configured to prevent fluctuations in AC power supply voltage when the AC power supply is near the rated value. The charging current of the capacitor is made substantially constant, and when the AC power source becomes smaller than the rated value, the phase width of the charging current is reduced.

According to the third aspect of the present invention, it is normally operated by an AC power supply, and when the peak value of the AC power supply is lowered, it is operated by an auxiliary power supply to turn on the lighting load, and a capacitor serving as an auxiliary power supply. In a lighting device comprising at least a charging control means for charging / discharging a capacitor and a power failure detection means for detecting turning off of a lighting load, the charging control means is in a normal state and a state where the peak value of the AC power supply is lowered. When switching between and, the phase width of the charging current is maintained at a substantially constant value or less.

According to the fourth aspect of the present invention, the power failure detection means detects a decrease in the peak value of the AC power source when the voltage across the capacitor reaches the set value.

[0023]

According to the invention described in claim 1, when the AC power supply is near the rated value, constant current charging of the capacitor C ₁ is performed against fluctuations in the power supply voltage, and when the AC power supply is below the rated value, the capacitor is charged. Narrow the charging current value to C ₁ .

According to the second aspect of the present invention, when the AC power source is near the rated value, the capacitor C ₁
Constant current charging is performed and the AC power supply becomes equal to or less than the rated value, the phase width of the charging current to the capacitor C ₁ is narrowed.

According to the third aspect of the invention, when switching between the normal state and the state where the peak value of the AC power source is lowered,
The phase width of the charging / discharging current is set to a predetermined value or less and the phase width of the charging / discharging current is gradually increased so that the voltage V ₁ across the capacitor C ₁ changes slowly.

According to the invention of claim 4, the AC power supply
Capacitor C due to decrease in peak value ₁Is not discharged
If you want to continue charging to the₁The voltage across
When the fixed value is reached, the peak of the AC power supply is detected by the power failure detection means.
The decrease in the value, that is, the turning off of the lighting load is detected.

[0027]

【Example】

 (Embodiment 1) FIG. 1 is a circuit diagram of a first embodiment according to the present invention.
Figures and 2 show pulsating voltage V₁And reference voltage V ₃Shows the relationship with
FIG. 16 is a characteristic diagram, different from the third conventional example shown in FIG. 15.
Is the voltage V across the smoothing capacitor CH._CHZener Die
Ode ZD₁Through the resistor R_{twenty one}, R_{twenty two}, R_{twenty three}Partial pressure with
Resistance R_{twenty three}Is the reference voltage V₃As comparator C
O₁To the comparator CO₁The output of
Input to the set (S) terminal of the flip-flop 2 and
Voltage V across Densa CH_CHResistance R₂₀， Switching element
Child Q₆Resetting the RS flip-flop 2 via
Input to the (R) terminal, and the "-" of the RS flip-flop 2 is input.
Switching element Q by output from Q "terminal₁Control
And the resistor R at the output end of the rectifier DB._{twenty five}, R
₂₆Of the resistor R₂₆Voltage V across_Ten
Switching element Q₆Applied between the base and emitter of
Switching element Q₆By controlling
The same components as those of the third conventional example are designated by the same reference numerals.
Therefore, the description is omitted. The resistance R _{twenty two}, R_{twenty three}Directly
Zener diode ZD at both ends of the column circuit₂Connected in parallel
Has been done.

Next, the operation will be briefly described with reference to FIG. End voltage V _CH is Zener smoothing capacitor CH - diode - de ZD ₁ and the Zener - diode - de ZD ₂ and the minimum voltage the minimum value required to turn on V _X, Zener - diode -
De ZD _1, zener - diode - Zener de ZD ₂ - When voltage and _{V ZD1, V ZD2, V X} = {(R 21 + R 22 + R 23) / (R 22 + R 23)} × V ZD2 ··· (3) and V _CH ≧ V _X・ ・ ・ ・ ・ ・ ・ ・ (4), V ₃ ≧ {R ₂₃ / (R ₂₂ + R ₂₃ )} × V _ZD2・ ・ ・ ・ ・ ・ ・ ・ ・ ・ (5)

First, when the voltage V _CH across the smoothing capacitor CH is equal to or higher than the minimum voltage V _X , the Zener diode ZD ₁ and the Zener diode ZD ₂ are on, so that the Zener diode is turned on. voltage current (V _F - charging current I _F characteristic)
2 is used, the reference voltage V ₃ rises as the voltage V _CH across the smoothing capacitor CH rises as shown in FIG. 2, and the slope becomes substantially the same as the slope shown in FIG. It is possible to perform constant current charging of ₁ . By changing the resistance R ₁ , the Zener
The values of the currents I _F1 and I _F2 flowing in the diode ZD ₁ and the Zener diode ZD ₂ can be changed.

Next, the voltage V across the smoothing capacitor CH_CHBut
Zener voltage V_ZD1With the above, the minimum voltage V_XIn the following cases,
Energy diode ZD₁Is off, Zener diode Z
D₂Turns on, so as shown in Fig. 2, the smoothing capacitor
Voltage V across CH_CHReference voltage V₃Is rising
And the slope is resistance R₁, R₂, R₃Can change
Can be set more easily by using
Capacitor C due to secondary voltage fluctuation of switch T₁Charging current to
Since the repetitive phenomenon of stop and restart of I is resolved,
The inclination cannot be increased and the inclination is small.
AC power supply V _acCapacitor C₁Charge to
The phase width of the flow becomes large and the power failure cannot be detected accurately.
And the resistance R₁, R₂, R₃To set an appropriate tilt
There is a need.

In this case, the reference voltage V₃Is C₁Voltage across
V₂Below, capacitor C₁Is from charging to resistance R₆To
Discharge through. Voltage V across smoothing capacitor CH
_CHIs the Zener voltage V_ZD1Below, Zener-Dio
-De ZD₁, Zener diode ZD₂Turn off together
Then, as shown in FIG.₃Becomes zero and the conde
Sensor C₁To the capacitor C₁Is resistance R₆
To discharge through. The capacitor C₁Of charge and discharge
Control is by switching element Q₁, Switching element Q₂
It can be easily done by controlling
Touching element Q ₁, Switching element Q₂Control of the
To give priority to the reset (S) signal over the reset (R) signal
The RS flip-flop 2 is used.

The operation will be briefly described below. Conde
Sensor C₁Voltage V across₂Is the reference voltage V₃Lower than
Is the comparator CO ₁Sends an L level signal to RS flip flow
The signal input to the R terminal because it is input to the S terminal of
, The "-Q" terminal outputs H level signal
Itching element Q₁, Switching element Q₂Turn on
So capacitor C₁Is charged.

Capacitor C₁Voltage V across₂Is the reference voltage
V₃Higher than the comparator CO ₁Is an H level signal
As a set signal to the S terminal of the RS flip-flop 2
Since it is input, the "-Q" terminal outputs an L level signal.
Switching element Q₁, Switching element Q₂Off
And capacitor C₁Charging stops.

Resistance R_{twenty five}, R₂₆And pulsating voltage V₁Zero black
Switch element Q ₆When turned off, flat
Resistance R from the positive terminal of the capacitor CH₂₀Through R
RS reset by inputting H level reset signal to the terminal
The "-Q" terminal of the flop 2 outputs an H level signal
Switching element Q₁, Switching element Q₂Again
Capacitor C₁Will resume charging.

With this configuration, the AC power source V
Capacitor C with constant current near the rated value against fluctuation of _ac
By charging ₁ and narrowing the charging current to the capacitor C ₁ below the rated value, the phase width of the charging current to the capacitor C ₁ can be kept below a certain value.

(Embodiment 2) FIG. 3 is a circuit diagram of a second embodiment according to the present invention. The difference from the first embodiment shown in FIG. 1 is that the resistor R ₂₃ has a resistor R ₂₆ at both ends. a series circuit of a capacitor C ₅ are connected in parallel, a switching element Q ₉ connected in parallel across the capacitor C _5, through a power failure detection circuit 3 rectifier DB at the positive output terminal and base of the switching element Q ₉ - And the emitter terminal of the switching element Q ₄ is connected to the negative terminal of the comparator CO ₁ , so that the peak value of the AC power supply V _ac decreases (normal lighting and emergency lighting). )
The charging current to the capacitor C ₁ at the time of switching is controlled, and the same configurations as those of the other first embodiment are denoted by the same reference numerals and the description thereof will be omitted.

Next, the operation will be briefly described with reference to FIGS. As shown in FIG. 4, the peak value of the AC power supply V _ac decreases, that is, the pulsating current voltage V ₁ decreases, and the power failure detection circuit 3
There determines that a power failure, the power failure detecting circuit 3 from the power failure detection signal S ₂ of the H level of the switching element Q ₉ base - switching element Q ₉ is input to the scan is turned on. Then, the voltage V ₃ across the capacitor C ₅ is set to zero and the charging of the capacitor C ₁ is stopped.

As shown in FIG. 5, when the power failure detection circuit 3 determines that the AC power supply V _ac is energized, the power failure detection circuit 3 inputs the L level power failure detection signal S ₂ to the base of the switching element Q _9. Switching element Q ₉ turns off and the Zener
Diode - de ZD _1, capacitor C ₅ via a resistor R _21, R _22, R ₂₆ is gradually charged, the charging of the capacitor C ₁ is started, the voltage across V ₂ of capacitor C ₁ is a capacitor C ₅ It gradually rises as the voltage V ₃ at both ends rises. As described above, since it takes time until the charging of the capacitor C ₁ becomes the constant current charging, it may be set so that the time for the charging current I to flow gradually increases.

[0039] (Embodiment 3) FIG. 6 is a circuit diagram of a third embodiment according to the present invention, FIG. 7 is an operation waveform diagram, a fifth conventional example differs from that shown in FIG. 19, the resistance R ₁₆ A resistor R ₃₁ is connected in series between the resistor and the ground, a switching element Q ₁₀ is connected in parallel across the resistor R ₃₁ , and the output power failure detection signal S ₂ of the comparator CO ₅ is connected to the base of the switching element Q _10. Also, the resistor R ₃₂ and the switching element Q ₁₁ are connected across the resistor R _18.
3 is connected in parallel, the output S ₃ of the comparator CO ₄ is also input to the base of the switching element Q ₁₁ , and the charge control circuit 4a shown in FIG. 3 is used instead of the charge control circuit 4a.
b is provided, and the same configurations as those of the other fifth conventional example are denoted by the same reference numerals and the description thereof will be omitted.

In this circuit, when the switching element Q ₁₀ is turned on, a low reference voltage V _5L obtained by dividing the pulsating current voltage V ₁ by the resistors R ₁₅ and R ₁₆ is obtained, and when the switching element Q ₁₀ is turned off, Ripple voltage V ₁ is applied to resistance R ₁₅ , resistance R _16, and resistance R
A high reference voltage V _5H (> V _5L ) _divided by ₃₁ is obtained. Further, when the switching element Q ₁₁ is turned off, a high reference voltage V _6H obtained by dividing the external power source Vref by the resistors R ₁₇ and R ₁₈ is obtained, and when the switching element Q ₁₁ is turned on, the external power source Vref is switched to the resistor R _17. And resistance R ₁₈ and resistance R ₃₂
A low reference voltage V _6L (<V _6H ) obtained by dividing by is obtained.
In this way, by switching the reference voltage V _6H and the reference voltage V _6L to provide a hysteresis for charging the capacitor C ₁ , it becomes easy to prevent malfunction due to noise.

Here, when the voltage fluctuation rate of the down transformer T is large, the secondary voltage of the down transformer T changes due to the change of the load impedance, so that the pulsating current voltage V ₁ is generated even in the non-power failure state. There is a case where it is judged to be a power failure by dropping to near zero, and therefore, in order to prevent it, the charge control circuit 4b is provided so that the phase width of the charging current I is kept below a certain value.

Next, the operation will be briefly described. First, when the switching element Q ₁₀ is off, the switching element Q ₁₁ is on, and the reference voltage V _5H <V _6L , the reference voltage V _5H and the reference voltage V _6L are compared by the comparator CO ₄ and output.
₃ is obtained, the switching element Q ₁₁ and the switching element Q ₇
Turn off. When the switching element Q ₁₁ is turned off, the reference voltage V ₆ rises from V _6L to V _6H . Also,
When the switching element Q ₇ is turned off and the voltage V _C3 across the capacitor C ₃ exceeds the reference voltage V ₇ , the comparator CO ₅ becomes H.
Outputs the level power failure detection signal S ₂ and charges control circuit 4b
And the switching element Q ₁₀ is turned on. When the switching element Q ₁₀ is turned on, the reference voltage V ₅ becomes V _5H
To V _5L to apply hysteresis.

Ripple voltage V ₁ rises, that is, reference voltage V _5L
Rises to V _5L > V _6H , H level S ₃ is obtained and the switching elements Q ₁₁ and Q ₇ are turned on. When the switching element Q ₁₁ is turned on, the reference voltage V ₆
Decreases from V _6H to V _6L . In addition, the switching element Q
_{When 7} is turned on and the voltage V _C3 across the capacitor C ₃ falls below the reference voltage V ₇ , the comparator CO ₅ outputs the L level power failure detection signal S ₂ and inputs it to the charge control circuit 4b and the switching element Q. Turn off ₁₀ .

Reference voltage V shown in FIG._FiveAnd V_C1And power failure detection
Signal S₂The shaded area in the operation waveform diagram with
C₁It corresponds to the part that is charged to. That is, time T₁Then
Switching element Q₇Is turned off and the capacitor C₁Is full
Powered, time T₂Then switching element Q₇Is turned on
Condenser C₁Discharges. Controls the phase of charging current I
AC power supply V_acThe phase does not exceed a certain value even if fluctuates
By doing so, time T₂Reference voltage V_FiveIs the charging voltage
It becomes less susceptible to the flow I. Therefore time T ₂Power outage
If it is set to detect, highly accurate power failure detection can be performed.
And are possible.

[0045]

According to the first to third aspects of the present invention, it is possible to provide a lighting device capable of charging the auxiliary power supply regardless of the voltage fluctuation of the AC power supply.

According to the invention described in claim 4, it is possible to provide an illumination device capable of instantaneously detecting a power failure.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment according to the present invention.

FIG. 2 is a diagram showing voltage characteristics according to the above embodiment.

FIG. 3 is a circuit diagram showing a second embodiment according to the present invention.

FIG. 4 is a diagram showing a voltage characteristic in the case of changing from a normal state to an emergency state according to the above embodiment.

FIG. 5 is a diagram showing a voltage characteristic when changing from an emergency state to a normal state according to the above embodiment.

FIG. 6 is a circuit diagram showing a third embodiment according to the present invention.

FIG. 7 is a diagram showing operation waveforms according to the embodiment.

FIG. 8 is a circuit diagram showing a first conventional example according to the present invention.

FIG. 9 is a diagram showing a voltage waveform of a capacitor according to the conventional example.

FIG. 10 is a diagram showing another voltage waveform of the capacitor according to the conventional example.

FIG. 11 is a diagram showing still another voltage waveform of the capacitor according to the conventional example.

FIG. 12 is a circuit diagram showing a second conventional example according to the present invention.

FIG. 13 is a diagram showing voltage characteristics according to the conventional example.

FIG. 14 is a diagram showing a voltage waveform of a capacitor according to the conventional example.

FIG. 15 is a circuit diagram showing a third conventional example according to the present invention.

FIG. 16 is a diagram showing voltage characteristics according to the conventional example.

FIG. 17 is a circuit diagram showing a fourth conventional example according to the present invention.

FIG. 18 is a diagram showing a voltage waveform of the capacitor according to the conventional example.

FIG. 19 is a circuit diagram showing a fifth conventional example according to the present invention.

FIG. 20 is a diagram showing operation waveforms according to the conventional example.

[Explanation of symbols]

 C capacitor 4 charge control means

Claims (4)

[Claims] 1. Normally, an AC power supply operates, and when the peak value of the AC power supply decreases, the auxiliary power supply operates to light a lighting load, and the capacitor serving as the auxiliary power supply and the capacitor are charged and discharged. In a lighting device comprising at least charge control means and power failure detection means for detecting turning off of a lighting load, the charge control means charges the capacitor against voltage fluctuations of the AC power supply when the AC power supply is near a rated value. A lighting device, wherein the current is made substantially constant and the value of the charging current is gradually reduced when the AC power source becomes gradually smaller than the rated value. 2. Normally, the AC power supply operates, and when the peak value of the AC power supply decreases, the auxiliary power supply operates to light the lighting load, and the capacitor serving as the auxiliary power supply and the capacitor are charged and discharged. In a lighting device comprising at least a charging control means and a power failure detection means for detecting the turning off of a lighting load, the charging control means is a charging current of the capacitor against an AC power supply voltage fluctuation when the AC power supply is near a rated value. Is substantially constant, and the phase width of the charging current is reduced when the AC power supply becomes smaller than the rated value. 3. Normally, it operates with an AC power supply, and when the peak value of the AC power supply decreases, it operates with an auxiliary power supply to light the lighting load, and charges and discharges the capacitor serving as the auxiliary power supply and the capacitor. In a lighting device comprising at least a charging control means and a power failure detection means for detecting the turning off of the lighting load, the charging control means is for switching between a normal state and a state where the peak value of the AC power supply is lowered. A lighting device, wherein the phase width of the charging current is maintained below a substantially constant value. 4. The power failure detection means is for detecting a decrease in the peak value of the AC power supply when the voltage across the capacitor reaches a set value. The lighting device according to any one of 1.