JP6870656B2 - Emergency lighting device - Google Patents

Description

The present invention relates to an emergency lighting device.

Conventionally, for example, as disclosed in Japanese Patent No. 3465406, an emergency light lighting device including a switching converter circuit for charging a battery to be used as a power source in an emergency is known. In the switching converter circuit according to this publication, a switching element is connected to the primary winding of the transformer, and the output voltage generated in the secondary winding of the transformer includes pulsation due to switching. An output smoothing capacitor is connected to the secondary winding of the transformer. The voltage generated in the secondary winding is supplied to the constant current circuit after its pulsation is suppressed by the output smoothing capacitor. The constant current circuit generates a charging current from this voltage, and the battery is charged.

Japanese Patent No. 3465406

The conventional emergency lighting device has a problem that harmonic countermeasures are not taken into consideration when charging the battery.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an emergency lighting device capable of taking measures against harmonics with a simple configuration without enlarging the circuit. ..

The emergency lighting device according to the present invention is
A flyback converter circuit that has a power factor improvement function and outputs a pulsation output voltage that is an output voltage including pulsation generated by the power factor improvement function.
Connected to the battery, the battery is charged by the charging current generated from the pulsating output voltage of the flyback converter circuit, and the output voltage of the flyback converter circuit is controlled to be a predetermined value. a charging circuit for the difference between the lower limit voltage value is constructed as reduced to reduce the charging current to the battery in the pulsating output voltage of the voltage value of the battery and the flyback converter circuit,
A lighting circuit that lights the lamp by supplying the electric power generated from the battery to the lamp.
To be equipped.

According to the present invention, since the charging circuit charges the battery by using the voltage generated by the flyback converter circuit having the power factor improving function, the harmonic countermeasure can be taken with a simple configuration without enlarging the circuit. It can be performed.

It is a figure which shows the charging circuit and the emergency light lighting device which concerns on embodiment of this invention. It is a figure which shows the charging circuit which concerns on embodiment of this invention. It is a graph which shows the relationship between the battery voltage and the charging current in the charging circuit which concerns on embodiment of this invention. It is a graph which shows the relationship between the battery voltage and the power consumption in the charging circuit which concerns on embodiment of this invention. It is a figure which shows the operation of the charging circuit which concerns on embodiment of this invention. It is a figure which shows the operation of the charging circuit which concerns on embodiment of this invention.

FIG. 1 is a diagram showing a charging circuit 13 and an emergency light lighting device 10 according to an embodiment of the present invention. The charging circuit 13 is included inside the emergency light 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 lamp, or an incandescent lamp. The inspection switch 2 is connected to a regular power supply (that is, a commercial AC power supply 1). The regular lighting device 6 is connected to the inspection switch 2. The regular lighting device 6 includes a converter circuit that converts electric power from the commercial AC power supply 1, and a known lighting device that lights the lamp 8 in the converter circuit can be used. The emergency light lighting device 10 lights the lamp 8 in place of the regular lighting device 6 in an emergency.

The emergency light 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 to generate a DC voltage. The charging circuit 13 charges the battery 60 using a DC voltage. The voltage conversion circuit 22 is an isolated boost converter circuit or the like 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 connecting 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 charging the battery 60, and releases the off signal in an emergency.

FIG. 2 is a diagram showing a charging circuit 13 according to an 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 IC50, diodes D1, D4, capacitors C1, C4, C5, resistors R3, a photocoupler composed of a phototransistor PC11 and a photodiode PC12, resistors R1, R2, and a constant voltage control unit 52. It has. The control IC 50 incorporates a MOSFET and a control circuit unit that controls ON / OFF of the MOSFET. The control circuit section of the control IC 50 includes a known power factor improving circuit having a PFC function. The voltage V1 is fed back to the control circuit section of the control IC50 via the photocoupler to control the voltage to a constant voltage. When the PFC operation is performed, the ripple of the commercial frequency is inevitably generated.

The current generation circuit 20 can be connected to the output smoothing capacitor C3 to generate _{a charging current IO that charges the battery 60 from the voltage of the output smoothing capacitor C3.} The voltage value of the battery 60 is also hereinafter referred to _{as "battery voltage V BAT".} The difference between the battery voltage V _{BAT and the lower limit value V RB} of the pulsating voltage V1 transmitted from the output smoothing capacitor C3 is also hereinafter referred to _{as “difference V X”.}

The current generation circuit 20 includes a transistor Q1, resistors R10, R11, R12, 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 for outputting a current supplied to the battery 60, and a control terminal for controlling conduction between the first terminal and the second terminal. In this 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. A 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. The resistor R13 is connected in parallel to the collector and the emitter of the transistor Q1. Since the reference voltage of the shunt regulator 201 is always applied to the resistor R12, a constant current operation is performed. Collector-emitter voltage V _CE of the transistor Q1 is controlled by changing such that the constant current. _{A voltage V1- (V BAT} + reference voltage) is always applied to the transistor Q1 and 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 resistor R10 and the resistor R11, and the base current of the transistor Q1 changes according to the voltage of the cathode.

The voltage V1 including pulsation (ripple) is also referred to as "pulsation voltage V1" for convenience. The waveform of the pulsating voltage V1 is shown in FIGS. 5 and 6 described later. The lower limit of the pulsating voltage V1 _{is also referred to as “V RB} ” below, the upper limit of the pulsating voltage V1 is also referred to as “V _RT ” below, and V _RB and V _RT are shown in FIGS. 5 and 6. As shown in equation (1) below, the difference between the lower limit value _{V RB} and the battery voltage _{V BAT} to as _{"V X".} By controlling the output voltage of the flyback converter circuit 14 to be constant, the lower limit value _VRB is assumed to be a constant value.
V _RB −V _BAT = V _X ... (1)

The internal reference voltage V _ref of the shunt regulator 201 is, for example, 1.25V. _{The forward voltage V be} required to turn on the transistor Q1 is, for example, V _be = 0.6 V. In the embodiment, if the relationship of the following equation (2) is established, the transistor Q1 is turned on, and the current generation circuit 20 outputs a constant current as the _{charging current I / O.}
V _X ≧ V _ref + V _be ... (2)
However, as shown in the following formula (3), the total of _{V ref} and V _{be is 1.85V.}
V _ref + V _be = 1.25 (V) +0.6 (V) = 1.85 (V) ... (3)

On the other hand, when the relationship of the following equation (4) is established, the collector current of the transistor Q1 is throttled, so that the charging current _IO is throttled.
V _X <1.85 (V) ・ ・ ・ (4)
Since V _RB is the lower limit value V _RB of the pulsation voltage V1, the pulsation voltage V1 periodically _{becomes higher than V RB} according to the pulsation, and is between the upper limit value V _RT and the lower limit value V _{RB of the pulsation voltage V1.} Round trip . Electrostatic difference between the voltage V1 and the battery voltage _{V BAT} according to the pulsation of the pressure V1 is that exceed 1.85V, the transistor Q1 is turned on, can flow a small amount of current.

As described above, in the present embodiment, the pulsation of the output voltage (that is, the voltage V1) that is inevitably generated in principle of the flyback converter circuit 14 is used. When the difference V _{X between the lower limit value V RB} of the pulsation of the voltage V1 and the battery voltage V _BAT is 1.85 V or more, the battery 60 is charged with a large charging current I _O. When the difference V _X is less than 1.85 V, the battery 60 is charged with a _{small charging current I O.}

FIG. 3 is a graph showing the relationship between the _{battery voltage VBAT} and the charging current in the charging circuit 13. FIG. 4 is a graph showing the relationship between the _{battery voltage VBAT} and the power consumption in the charging circuit 13. 5 and 6 are diagrams showing the operation of the charging circuit 13. As an example, it is assumed that the voltage V1 is about 10 V, _{the maximum value of the charging current IO} is 123 mA, and the 6-cell battery 60 is charged.

As shown in FIG. 3, when the battery voltage V _BAT is in the range of 5 V to about 7.5 V, the charging current _IO maintains 123 mA, and the current generation circuit 20 operates as a constant current circuit. The situation at this time is shown in FIG. When the battery voltage V _BAT is 5 V, the difference V _X is about 4.3 V. Since the difference V _X is secured sufficiently larger than 1.85 V, the transistor Q1 can be turned on to allow a charging current I _{O of} 123 mA to flow. Since the difference V _{X between the lower limit value V RB} of the pulsation of the voltage V1 and the battery voltage V _BAT is about 1.85 V, the charging current _IO maintains 123 mA and the power consumption remains unchanged at 2.3 W. As shown in FIG. 3, the higher the _{battery voltage V BAT} , the smaller the _{difference V X proportionally.}

As shown in FIG. 3, when the battery voltage V _BAT reaches about 7.5 V, the charging current _IO decreases almost proportionally so that the higher the battery voltage V _{BAT is, the lower it is.} Specifically, when the battery voltage V _BAT rises to about 8 V, the difference V _X becomes less than 1.85 V, and the base-emitter voltage V _be for turning on the transistor Q1 cannot maintain the magnitude of 0.6 V, so charging is performed. The current _IO decreases. This situation is shown in FIG. As the battery voltage V _BAT rises to 8 V, the difference V _X becomes less than 1.85 V.

As shown in FIG. 4, the power consumption is 1.9 W when the _{battery voltage V BAT in a fully charged state is about 9 V.} According to this embodiment, the power consumption is reduced by about 17% as compared with the case where the _{charging current IO} is continuously maintained at 123 mA regardless of the _{battery voltage V BAT.}

As described above, according to the charging circuit 13 according to the present embodiment, the pulsation (ripple) of the voltage V1 is positively transmitted to the subsequent stage of the output smoothing capacitor C3, and the battery 60 is fully charged by utilizing this pulsation. When approaching, the charging current I _O can be throttled and flowed. Since the output smoothing capacitor C3 may be a small-capacity electrolytic capacitor that does not suppress the pulsation of the voltage V1, it is small and requires a small mounting area. This has the advantage that the power consumption during charging can be suppressed and the output smoothing capacitor C3 can be made small.

Further, since the current generation circuit 20 outputs the maximum charging current I _{O when the difference V X} is 1.85 V or more predetermined, charging can be performed quickly. In particular, in the present embodiment, the current generation circuit 20 acts as a constant current circuit when _{the difference V X} is 1.85 V or more, and generates a constant current as _{the charging current I O.} On the other hand, the current generation circuit 20 reduces the charging current I / _{O when the difference V X is less than 1.85 V.} In particular, in the present embodiment, when the difference V _X is less than 1.85 V, the current generation circuit 20 reduces the magnitude of the charging current as the voltage of the battery 60 increases, so that the power consumption is more effective. Can be suppressed.

In the present embodiment, V _ref + V _be = 1.85 V corresponds to the "predetermined value" according to the present invention. This numerical value of 1.85V is a numerical value _{under the conditions of V ref} = 1.25V and V _be = 0.6V in the circuit configuration according to the present embodiment, and the present invention is not limited thereto. Absent. In addition, the "predetermined value" is V _ref + V _be , but when actually designing, a margin of voltage between collector and emitter is required, so set it higher by 0.1 V or more. Is preferable.

_{The lower limit value V RB} of the pulsation of the voltage V1 _{is set so that the difference V X} falls below 1.85 V when the charge amount of the battery 60 becomes equal to or more than the “predetermined charge amount less than the predetermined full charge”. For example, the predetermined charge amount may be set to any amount within the range of 50% or more and less than 100% of the full charge of the battery 60, specifically, 50%, 51%, 52%, ... ... 60%, ... 65%, ... 70%, ... 75%, ... 80%, ... 85%, or 90% may be set. For example, in FIG. 3, when the battery voltage V _BAT at the time of full charge is 9 V, the difference V _X is less than 1.85 V when the battery voltage V _{BAT is 7.5 V.} In this case, assuming that the charge amount is 100% when the _{battery voltage V BAT} is 9 V, the charge amount is about 73% when the _{battery voltage V BAT is 7.5 V by simple calculation. That is, the difference V X} falls below 1.85 V at a charge amount of about 73%, and the operation of starting to throttle the _{charging current I O is realized.} The method for calculating the charge amount of the battery 60 described here is merely an example 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 when the charge amount is tens of percent when the charge current _IO is started to be throttled. However, in the present embodiment, it is intended _{to reduce unnecessary charging current IO} near the full charge of the battery 60 and suppress power consumption. Therefore, it is preferable to start _reducing the charging current _IO at a battery voltage V BAT which is close to full charge and has a high battery voltage.

The lower limit value _VRB can be adjusted by setting the output voltage of the flyback converter circuit 14 and the capacitance value of the output smoothing capacitor C3. If the output voltage of the flyback converter circuit 14 is increased, the lower limit value _VRB also increases. The larger the capacitance of the output smoothing capacitor C3, the smoother the output voltage V1 and the higher the _{lower limit value VRB.} In this embodiment, a constant current circuit composed of an NPN transistor and a shunt regulator is used for the current generation circuit 20. However, the present invention is not limited to this, and a constant current circuit configured by using a PNP transistor and other constant voltage elements may be used for the current generation circuit 20.

1 Commercial AC power supply, 2 Inspection switch, 3 Lighting 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, 50 control IC, 52 constant voltage control unit, 60 battery, 201 shunt regulator, C1 capacitor, C3 output smoothing capacitor, D1, D4 diode, _IO charging current, PC11 phototransistor, PC12 photodiode, Q1 transistor, R1, R10, R11, R12, R13, R2, R3 resistor, T1 primary winding, T2 secondary winding, T3 auxiliary winding, TR transformer

Claims (1)

A flyback converter circuit that has a power factor improvement function and outputs a pulsation output voltage that is an output voltage including pulsation generated by the power factor improvement function.
Connected to the battery, the battery is charged by the charging current generated from the pulsating output voltage of the flyback converter circuit, and the output voltage of the flyback converter circuit is controlled to be a predetermined value. a charging circuit for the difference between the lower limit voltage value is constructed as reduced to reduce the charging current to the battery in the pulsating output voltage of the voltage value of the battery and the flyback converter circuit,
A lighting circuit that lights the lamp by supplying the electric power generated from the battery to the lamp.
An emergency lighting device equipped with.

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