JP6405863B2 - Lighting device - Google Patents

Description

The present invention relates to a lighting device .

  Conventionally, for example, as disclosed in Japanese Patent Application Laid-Open No. 2001-218388, a charging device and an emergency lamp lighting device that can appropriately charge a battery even when the battery is empty or nearly empty are known. Yes. The emergency light lighting device charges an externally connected battery during normal use, while lighting the emergency light lamp using the power of the battery during emergency. Since a large amount of charging current is required when the battery is empty or nearly empty, the voltage of the charging circuit may be lower than a predetermined value and erroneously determined as an emergency. In this regard, in the technique according to the above publication, erroneous determination is prevented by detecting the charging current.

JP 2001-218388 A

  By the way, there is a method for avoiding the above-described problem of erroneous determination by using a constant current circuit for charging the battery. The voltage used for the power source of the constant current circuit is usually higher than the voltage when the battery is fully charged. When the battery is charged, a difference between the voltage used for the power source of the constant current circuit and the battery voltage is applied to the constant current circuit. When the battery is short-circuited or when the battery is empty or nearly empty, the battery voltage is low. When the battery voltage is low, there is a problem that the voltage applied to the constant current circuit becomes high and heat generation of the constant current circuit increases.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an illumination device that can suppress the heat generation of a circuit that generates a charging current.

Lighting device according to the present invention, light source, a conventional lighting apparatus that generates electric power from the AC power of the AC power supply to turn on the light source, battery and, emergency lights lit for producing electrical power for lighting the light source from the battery The emergency light lighting device is connected to a wiring connecting the AC power source and the regular lighting device, and rectifies the AC power of the AC power source to generate a first DC voltage. A circuit; a charging circuit for charging the battery by generating a current from the first DC voltage; a voltage conversion circuit for converting the voltage of the battery; an output terminal connected to the light source; and the regular lighting A first input terminal for connecting to the device, and a second input terminal to which an output voltage of the voltage conversion circuit is supplied, and the first input terminal and the second input terminal are connected to the output terminal. Selective contact A relay, and the charging circuit includes a voltage generation circuit that generates a second DC voltage from the first DC voltage, and a current generation circuit that generates a current from the second DC voltage, The current generation circuit detects a voltage of the battery to be charged with the current, and outputs a first current when the battery voltage is equal to or lower than a predetermined threshold voltage, and the battery voltage reduces the threshold voltage. When it exceeds, a second current larger than the first current is output, and the emergency lamp lighting device uses the second DC voltage generated by the voltage generation circuit of the charging circuit for controlling the relay. It is constructed to be used as control power.

  According to the present invention, when the battery voltage is low, the charging current of the battery is reduced, so that the heat generation of the current generation circuit can be reduced.

It is a figure which shows the charging circuit and emergency light lighting device concerning embodiment of this invention. It is a figure which shows the charging circuit concerning embodiment of this invention. It is a graph which shows the relationship between the battery voltage and power consumption in the charging circuit concerning embodiment of this invention. It is a graph which shows the relationship between the battery voltage and power consumption in the charging circuit concerning a comparative example.

  FIG. 1 is a diagram showing a charging circuit 13 and an emergency lamp lighting device 10 according to an embodiment of the present invention. The charging circuit 13 is included in the emergency lamp lighting device 10. FIG. 1 also shows a lighting device 3 including an emergency light lighting device 10. The lighting device 3 includes a lamp 8, an inspection switch 2, a regular lighting device 6, an emergency light lighting device 10, and a battery 60. The lamp 8 is a lamp such as a fluorescent lamp, a halogen, or an incandescent lamp. The inspection switch 2 is connected to a normal power source (that is, a commercial AC power source 1). The regular lighting device 6 is connected to the inspection switch 2. The regular lighting device 6 includes a converter circuit that converts power from the commercial AC power source 1, and a known lighting device that lights the lamp 8 with the converter circuit can be used. The emergency light lighting device 10 lights the lamp 8 instead of the regular lighting device 6 in an emergency.

  The emergency lamp lighting device 10 includes a full-wave rectifier circuit 12, a charging circuit 13, a voltage conversion circuit 22, a relay 24, a control power supply circuit 16, and a control circuit 18. The full-wave rectifier circuit 12 rectifies AC power and generates a DC voltage. The charging circuit 13 charges the battery 60 using a DC voltage. For example, when the lamp is a fluorescent lamp, the voltage conversion circuit 22 includes an insulating step-up converter circuit that converts the voltage of the battery 60, and generates electric power for lighting the lamp 8 from the voltage of the battery 60 in an emergency. . The relay 24 includes an output terminal, a first input terminal for connection to the regular lighting device 6, and a second input terminal to which the output voltage of the voltage conversion circuit 22 is supplied. The relay 24 can selectively connect the first input terminal and the second input terminal to the output terminal. The control power supply circuit 16 acquires control power from the charging circuit 13 and controls the relay 24. The control circuit 18 sends an off signal to the voltage conversion circuit 22 while the battery 60 is being charged, and cancels the off signal in an emergency.

  FIG. 2 is a diagram showing the charging circuit 13 according to the embodiment of the present invention. The charging circuit 13 includes a flyback converter circuit 14 and a current generation circuit 20. The flyback converter circuit 14 includes a transformer TR having a primary winding T1 and a secondary winding T2, and an output smoothing capacitor C3 connected in parallel to the secondary winding T2. A DC voltage is input to the primary winding T1. The secondary winding T2 is connected to the diode D1, and the pulsating voltage generated in the secondary winding T2 is smoothed by the output smoothing capacitor C3.

  The flyback converter circuit 14 further includes a control IC 50, a diode D4, capacitors C1, C4, and C5, a resistor R3, a photocoupler including a phototransistor PC11 and a photodiode PC12, resistors R1 and R2, and a constant voltage controller 52. ing. The control IC 50 has a built-in MOSFET and a control circuit unit that controls on / off of the MOSFET. The control circuit unit of the control IC 50 includes a known power factor correction circuit having a PFC function. The voltage V1 is fed back to the control circuit unit of the control IC 50 through a photocoupler to control it at a constant voltage.

The current generation circuit 20 is connected to the output smoothing capacitor C3 and can generate a charging current I _BAT for charging the battery 60 from the voltage V1 of the output smoothing capacitor C3. Hereinafter, the voltage value of the battery 60 is also referred to as “battery voltage V _BAT ”.

The current generation circuit 20 includes a constant current circuit 202 and a variable resistance circuit 203. The constant current circuit 202 generates a current from the voltage V1 of the output smoothing capacitor C3. Constant current circuit 202 includes a transistor Q1, resistors R10, R11, R12, and R13, and a shunt regulator 201. The transistor Q1 includes a first terminal to which the voltage of the output smoothing capacitor C3 is applied, a second terminal that outputs a current supplied to the battery 60, and a control terminal that controls conduction between the first terminal and the second terminal. In the present embodiment, the transistor Q1 is a bipolar transistor, the first terminal is a collector, the second terminal is an emitter, and the control terminal is a base. The voltage V1 is supplied to one end of the series circuit of the resistors R10 and R11, and the other end of the series circuit of the resistors R10 and R11 is connected to the base of the transistor Q1. Resistor R13 is connected in parallel to the collector and emitter of transistor Q1. Since the reference voltage V _ref of the shunt regulator 201 is always applied to the resistor R12, a constant current operation is performed. The collector-emitter voltage V _CE of the transistor Q1 is changed and controlled so as to have a constant current. Transistor Q1, the voltage _{V1- (V} BAT ₊ V _ref) is applied to the resistor R13. The anode of the shunt regulator 201 is connected to the connection point between the battery 60 and the resistor R12. The reference terminal of the shunt regulator 201 is connected to the connection point between the emitter of the transistor Q1 and the resistor R12. A voltage corresponding to the emitter current of the transistor Q1 and the current flowing through the resistor R13 is input to this reference terminal. The cathode of the shunt regulator 201 is connected to the connection point between the resistors R10 and R11, and the base current of the transistor Q1 changes according to the voltage of the cathode.

The variable resistance circuit 203 is provided between the constant current circuit 202 and the battery 60, and the resistance value between them can be changed. The variable resistance circuit 203 sets the resistance between the constant current circuit 202 and the battery 60 to the first resistance value when the battery voltage _VBAT is equal to or lower than a predetermined threshold voltage _VTH . When the battery voltage V _BAT exceeds the threshold voltage V _TH , the variable resistance circuit 203 sets the resistance between the constant current circuit 202 and the battery 60 to a second resistance value that is smaller than the first resistance value. As will be described later, the first resistance value is the resistance value of the resistor R12. The second resistance value is a resistance value when the resistor R12 and the resistor R15 are connected in parallel, and is a value smaller than the first resistance value. For example, when the resistance R12 and the resistance R15 have the same resistance value, the second resistance value is half of the first resistance value.

As described above, the resistor R12 is inserted between the reference terminal of the shunt regulator 201 and the battery 60. The variable resistance circuit 203 includes a resistor R15, a second transistor Q2, and a MOSFET Q3. In order to make the description of the relationship between the resistors R12 and R15 easier to understand, the resistor R12 is hereinafter also referred to as “first resistor R12” and the resistor R15 is also referred to as “second resistor R15” for convenience. The second resistor R15 is connected in parallel to the first resistor R12. The second transistor Q2 and the MOSFET Q3 are switching means for switching the connection between the first resistor R12 and the second resistor R15. Specifically, the second transistor Q2 and MOSFETQ3, when the battery voltage _{V BAT} is equal to or less than the threshold voltage _{V TH} is disconnected in parallel connection of the first resistor R12 and the second resistor R15, the battery voltage _{V BAT} is the threshold When the voltage _VTH is exceeded, the second resistor R15 is connected in parallel to the first resistor R12.

More specifically, in order to selectively perform parallel connection of the second resistor R15, the variable resistor circuit 203 includes a second transistor Q2, which is a bipolar transistor, a P-channel MOSFET Q3, and resistors R14, R16, R17 is provided. One end of the resistor R14 is connected to a connection point between the second resistor R15 and the source of the MOSFET Q3. The drain of the MOSFET Q3 is connected to the connection point between the first resistor R12 and the battery 60. The other end of the resistor R14 is connected to a connection point between the gate of the MOSFET Q3 and the collector of the second transistor Q2. One end of the resistor R17 is connected to a connection point between the first resistor R12 and the battery 60, the other end of the resistor R17 is connected to one end of the resistor R16, and the other end of the resistor R16 is connected to a reference potential. The base of the second transistor Q2 is connected to the connection point between the resistors R17 and R16, and the emitter of the second transistor Q2 is connected to the reference potential. In such a circuit configuration, when the battery voltage V _BAT is equal to or lower than the threshold voltage V _TH , the second transistor Q2 is turned off, and when the battery voltage V _BAT exceeds the threshold voltage V _TH , the second transistor Q2 is turned on. Thus, the second transistor Q2 and the resistors R16 and R17 are designed in advance. The threshold voltage V _TH can be set to an arbitrary value in advance, and is set to 3.5 V as an example in the present embodiment.

When the second transistor Q2 is off, the MOSFET Q3 is also off, and the other end of the second resistor R15 is open. At this time, only the first resistor R12 is interposed between the emitter of the first transistor Q1 and the battery 60. On the other hand, when the second transistor Q2 is on, the MOSFET Q3 is also on, and the other end of the second resistor R15 is connected to the battery 60. That is, the second resistor R15 is inserted in parallel with the first resistor R12. Thus, a parallel circuit of the first resistor R12 and the second resistor R15 is interposed between the emitter of the first transistor Q1 and the battery 60. When the second resistor R15 is connected in parallel to the first resistor R12 alone, the resistance value between the emitter of the transistor Q1 and the battery 60 is reduced, so that a larger charging current I _BAT is supplied to the battery 60. Supplied.

  Hereinafter, the operation of the charging circuit 13 and the effect of suppressing circuit heat generation will be described. FIG. 3 is a graph showing the relationship between the battery voltage and the power consumption in the charging circuit 13. Further, as a comparative example for explaining the operation of the charging circuit 13 of the present embodiment, a case where the variable resistance circuit 203 is not provided will be described. Specifically, in this comparative example, the variable resistor circuit 203 is removed from the current generation circuit 20, and the second resistor R15 is always connected in parallel to the first resistor R12. FIG. 4 is a graph showing the relationship between the battery voltage and the power consumption in the charging circuit without the variable resistance circuit 203.

When "the voltage V1 and the difference between the battery voltage _{V BAT"} is greater than "the sum of the base-emitter voltage _{V be} of the reference voltage _{V ref} and the first transistor Q1 of the shunt regulator 201 ', the charge current _{I BAT} is supplied to the battery 60 The Since most of the charging current I _BAT flows through the first transistor Q1, the first transistor Q1 generates heat.

FIG. 4 is a graph showing the relationship between the charging current I _BAT and the power consumption of the first transistor Q1 in the charging circuit 13 when the variable resistance circuit 203 is not provided. However, it is assumed that the voltage V1 = 13V, the resistance R10 = 1 kΩ, the resistance R11 = 56Ω, the resistance R12 = 22Ω, the resistance R13 = 180Ω, and the resistance R15 = 18Ω. It is assumed that the shunt regulator 201 with V _ref = 1.25 V is used, and the characteristics when the battery voltage V _BAT is changed are shown.

When the battery 60 is nearly empty (battery voltage V _BAT = 0V), power exceeding 1 W is consumed by the first transistor Q1. When the power consumption is large, heat generation can be suppressed by adding a heat radiating component or increasing the size of the component. However, such measures cause an increase in mounting area and cost.

Therefore, in the present embodiment, as shown in FIG. 2, the variable resistance circuit 203 is provided in the current generation circuit 20 so as to detect the battery voltage V _BAT and switch the charging current I _BAT . In the circuit configuration shown in FIG. 2, when the battery voltage V _BAT is equal to or higher than the threshold voltage V _TH (3.5 V in the present embodiment), the MOSFET Q3 is on, so that it is almost the same as the circuit configuration without the variable resistance circuit 203. It will be the same.

When the battery voltage V _BAT is lower than the threshold voltage V _TH , the MOSFET Q3 is turned off, so that no current flows through the resistor R15 and the charging current I _BAT decreases.

FIG. 3 shows a change in the charging current I _BAT and the power consumption in the first transistor Q1 when the battery voltage V _BAT changes. Current generating circuit 20 detects the battery voltage _{V BAT,} when the battery voltage _{V BAT} is equal to or less than the threshold voltage _{V TH} and outputs a constant current of about 0.07 A, the battery voltage _{V BAT} exceeds the threshold voltage _{V TH} In this case, the charging current I _BAT is increased to output a constant current of about 0.13A. The threshold voltage V _TH is 3.5V. In particular, the current generation circuit 20 switches between a constant current of about 0.07 A and a constant current of about 0.13 A in a stepwise manner, that is, discontinuously, with the threshold voltage V _TH as a boundary. As a result, when the battery voltage V _BAT is low, the charging current I _BAT is lowered, so that the heat generation of the first transistor Q1 can be reduced.

As shown in FIG. 3, when the battery voltage _{V BAT} is equal to or less than the threshold voltage _{V TH,} rather than when the battery voltage _{V BAT} is greater than the threshold voltage _{V TH,} to reduce the charge current _{I BAT} to approximately 1/2 be able to. Thereby, compared with FIG. 4, the power consumption in the first transistor Q1 in the region where the battery voltage _VBAT is low can be suppressed.

  In the present embodiment, the constant current circuit 202 has a circuit configuration including the transistor Q1, the resistors R10, R11, R12, and R13, and the shunt regulator 201, but the present invention is not limited to this. Since various circuit configurations are already known as the constant current circuit, by applying these known constant current circuits to the constant current circuit 202, a constant current may be generated from the voltage V1.

  As a modification of the embodiment of the present invention, the variable resistor circuit 203 is removed from the charging circuit 13, the second resistor R15 is always connected in parallel to the first resistor R12, and the resistor R11 connected to the base of the first transistor Q1 is added. It may be changed as a variable resistance portion, and thereby the same effect as in the embodiment can be obtained. The variable resistance unit may be one in which a resistor is selectively connected to the resistor R 11 in FIG. 2, and the selective parallel connection of the resistors may be performed by a mechanism similar to that of the variable resistor circuit 203. In terms of reliability and the like, the current generation circuit 20 of FIG. 2 that can make the resistance value connected to the base constant is superior.

In the present embodiment, the threshold voltage V _TH is set to 3.5 V, but the present invention is not limited to this. It may be higher than 3.5V or lower than 3.5V. Here, the threshold voltage V _TH may be set based on the charge amount of the battery 60. That is, the battery voltage V _BAT may be determined to match the threshold voltage V _TH when the charge amount of the battery 60 reaches “a predetermined charge amount that is 0% or more and less than full charge”. For example, the predetermined charge amount may be set to any amount within the range of 0% or more and less than 50% of the full charge of the battery 60, specifically, 10%, 20%, 30%, 40 % Or 50%. For example, in FIG. 3, the battery voltage V _BAT at full charge is set to 9V. In this case, assuming that the charge amount is 100% when the battery voltage V _BAT is 9V, the charge amount when the battery voltage V _BAT is 3.5V is approximately 39% in a simple calculation. That is, an operation is realized in which the battery voltage V _BAT reaches 3.5 V, which is the threshold voltage V _TH , with the charge amount of about 39%, and the charging current I _BAT is switched. The calculation method of the charge amount of the battery 60 described here is illustrated for convenience and does not limit the present invention. Since there is a correlation between the battery voltage V _BAT and the charge amount of the battery 60, it may be arbitrarily determined whether the charge current I _BAT is switched when the charge amount is several tens of percent. However, the present embodiment is intended to suppress the circuit heat generation during charging by suppressing the charging current I _BAT when the battery 60 is empty or nearly empty. Therefore, it is preferable that the charging current I _BAT is switched to a low value at least when the battery voltage V _BAT is at least empty or close to empty.

  The charging circuit 13 according to the above-described embodiment includes a flyback converter circuit 14. However, the present invention is not limited to this. A voltage generation circuit capable of generating the voltage V1 may be used for the current generation circuit 20, and specifically, a converter circuit other than a flyback converter may be applied.

DESCRIPTION OF SYMBOLS 1 Commercial AC power supply, 2 Inspection switch, 3 Illumination device, 6 Regular lighting device, 8 lamp, 10 Emergency light lighting device, 12 Full wave rectifier circuit, 13 Charging circuit, 14 Flyback converter circuit, 16 Control power supply circuit, 18 Control Circuit, 20 current generation circuit, 22 voltage conversion circuit, 24 relay, 52 constant voltage control unit, 60 battery, 201 shunt regulator, 202 constant current circuit, 203 variable resistance circuit, C3 output smoothing capacitor, D1, D4 diode, 50 control IC, PC11 phototransistor, PC12 photodiode, Q1, Q2 transistor, Q3 MOSFET, T1 primary winding, T2 secondary winding, T3 auxiliary winding, TR transformer

Claims (3)

A light source;
A conventional lighting apparatus from the AC power of the AC power supply that generates power to light the light source,
Battery,
An emergency light lighting device for generating electric power for lighting the light source from the battery;
Including
The emergency light lighting device is:
A rectifier circuit connected to a wiring connecting the AC power source and the regular lighting device, and rectifying AC power of the AC power source to generate a first DC voltage;
A charging circuit for charging the battery by generating a current from the first DC voltage;
A voltage conversion circuit for converting the voltage of the battery;
An output terminal connected to the light source; a first input terminal for connecting to the regular lighting device; and a second input terminal to which an output voltage of the voltage conversion circuit is supplied; A relay capable of selectively connecting the first input terminal and the second input terminal;
With
The charging circuit is
A voltage generating circuit for generating a second DC voltage from the first DC voltage;
A current generation circuit for generating a current from the second DC voltage;
With
The current generation circuit detects a voltage of the battery to be charged with the current, and outputs a first current when the battery voltage is equal to or lower than a predetermined threshold voltage, and the battery voltage reduces the threshold voltage. If it exceeds, output a second current larger than the first current ,
The emergency lamp lighting device is a lighting device constructed to use the second DC voltage generated by the voltage generation circuit of the charging circuit as control power used for controlling the relay . The current generation circuit includes:
When the battery voltage is equal to or lower than the threshold voltage, a first constant current is output as the first current, and when the battery voltage exceeds the threshold voltage, a second constant current is output as the second current. The lighting device according to claim 1, wherein the first constant current and the second constant current are switched stepwise so as to output the current. The current generation circuit includes:
A constant current circuit for generating a constant current from the second DC voltage;
Provided between the constant current circuit and the battery, the value of the resistance between the constant current circuit and the battery can be changed, and when the voltage of the battery is equal to or lower than the threshold voltage, the resistance A variable resistance circuit for setting the resistance to a second resistance value smaller than the first resistance value when the battery voltage exceeds the threshold voltage,
The lighting device according to claim 1, comprising:

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