Power supply

Abstract

To provide an electric power source device enabling the power consumption thereof to be reduced.SOLUTION: An electric power source device 2 comprises a first electric power conversion circuit 5, a charging circuit 7, a second control unit 25, and a second electric power conversion circuit 8. The first electric power conversion circuit 5 has a switching transformer 15 and receives an input voltage 9. The charging circuit 7 charges a secondary battery 6 from one secondary winding 15b1 of the switching transformer 15. The second control unit 25, when receiving the input voltage 9, obtains an electric power source from the other secondary winding 15b2 different from the one secondary winding 15b1, of the switching transformer 15. The operation of the second electric power conversion circuit 8 is controlled by the second control unit 25.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a power supply device including a power conversion circuit having a switching transformer. [Background technology]

[0002] Conventionally, there are emergency lights and emergency lights as lighting devices for displaying directions to evacuation routes. In emergency lights, when an external power source such as a commercial AC power source is input, the light source such as an LED, which is a load, is turned on by the power from the external power source and a secondary battery is charged. When the external power source is cut off due to a power outage, that is, in an emergency when the external power source is not input, the emergency light source is turned on by the power from the charged secondary battery. Such power supply devices are generally designed to consume less than 3W of power. On the other hand, in the input current harmonic standard for lighting equipment, when multiple power supply units are wired together in the same equipment, if the power consumption of the power supply unit is less than 2W, it is determined that the equipment consumes sufficiently little power that the measurement of harmonic current is not required. In this way, lowering the power consumption is advantageous for the application of the above harmonic standard, so lowering the power consumption is desirable. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-54509 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a power supply device capable of suppressing power consumption. [Means for solving the problem]

[0005] A power supply device according to an embodiment includes a first power conversion circuit, a charging circuit, a control unit, and a second power conversion circuit. The first power conversion circuit has a switching transformer and receives an input voltage. The charging circuit charges a storage battery from one secondary winding of the switching transformer. When the input voltage is input, the control unit obtains power from another secondary winding different from the one secondary winding of the switching transformer. The operation of the second power conversion circuit is controlled by the control unit. The control unit controls the charging of the storage battery in the charging circuit intermittently so that the power consumption is 2W or less. . Effect of the Invention

[0006] According to the power supply device of the embodiment, it is expected that loss in the control unit can be suppressed, and power consumption can be suppressed. [Brief description of the drawings]

[0007] [Figure 1] 1 is a circuit diagram of a power supply device according to an embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment will be described with reference to the drawings.

[0009] In FIG. 1, 1 denotes a lighting device. In this embodiment, the lighting device 1 will be described taking an emergency light as an example. In the lighting device 1, a light source module 4, which is a load module including a light source 3 as a load, can be detachably attached to a power supply device 2. As the light source 3, a light bulb or a light emitting element can be used, but in this embodiment, for example, an LED is used as a light emitting element that is a solid light source, and these light sources 3 are electrically connected in series. Note that, instead of an LED, an organic EL element or an inorganic EL element may be used as the light source 3.

[0010] The power supply device 2 includes a first power conversion circuit 5 which is a power conversion circuit, a storage battery which is a backup power supply, i.e., a secondary battery (battery) 6, a charging circuit 7 which charges the secondary battery 6, and a second power conversion circuit 8 which is a power conversion circuit. The secondary battery 6 is a rechargeable battery pack in which multiple DC power sources are electrically connected in series, and has a capacity which allows the light source 3 to be kept lit with a predetermined luminous flux for a predetermined period of time or more when an input voltage 9 which is an external power source such as a commercial AC power source is cut off. For example, a nickel-metal hydride battery is used as the secondary battery 6. The secondary battery 6 has one or more cells.

[0011] In the lighting device 1, when an input voltage 9 is being input, the power supply device 2 uses the input voltage 9 as a power source, charges the secondary battery 6 through the charging circuit 7 with the output from the first power conversion circuit 5 which converts the voltage of the input voltage 9, and converts the output from the first power conversion circuit 5 through the second power conversion circuit 8 and supplies it to the light source 3 to light up the light source 3, and when the input voltage 9 is not being input, during an emergency or power outage (cutoff), when the input voltage 9 is not being input, uses the secondary battery 6 as a power source, converts the output from the secondary battery 6 through the second power conversion circuit 8 and supplies it to the light source 3 to light up the light source 3, thereby accurately informing people of the location of an emergency exit and the evacuation direction and providing guidance. The lighting device 1 is installed, for example, by being attached to an installation surface such as a ceiling surface or a vertical wall surface, or by being embedded in the floor surface.

[0012] The first power conversion circuit 5 has an input voltage 9 as an input side and a charging circuit 7, i.e., a secondary battery 6 as an output side. In this embodiment, the input voltage 9 is an AC voltage, and the first power conversion circuit 5 receives a voltage obtained by rectifying the input voltage 9, which is an AC voltage. When the input voltage 9 is input, the first power conversion circuit 5 performs constant current control, constant voltage control, or constant power control on the input AC voltage. The first power conversion circuit 5 is electrically connected to the input voltage 9 via a noise prevention circuit 11, which is a filter circuit that removes noise from the input voltage 9 side, a primary side rectification means 12, which is a rectification means that rectifies the AC voltage from the input voltage 9, and a primary side smoothing means 13, which is a smoothing means that smoothes the output of the primary side rectification means 12. That is, a DC voltage is input to the first power conversion circuit 5. Although not shown, the noise prevention circuit 11 includes, for example, a varistor and a capacitor electrically connected between the power supply lines, and a common mode choke coil. The primary side rectification means 12 is electrically connected to the output side of the noise prevention circuit 11. A full-wave rectifying means such as a diode bridge is used as the primary side rectifying means 12. A primary side smoothing means 13 is electrically connected to the output side of the primary side rectifying means 12. A smoothing element such as an electrolytic capacitor is used as the primary side smoothing means 13.

[0013] Moreover, the first power conversion circuit 5 insulates the secondary battery 6 side from the input voltage 9 side. Since the lighting device 1 charges the secondary battery 6, it is preferable that the first power conversion circuit 5 is insulated from the input voltage 9 in consideration of safety. In this embodiment, the first power conversion circuit 5 is an isolated flyback converter. Moreover, the first power conversion circuit 5 is a switching circuit having at least one switch means, and converts the input voltage 9 by the switching operation of the switch means. The first power conversion circuit 5 includes a switching transformer 15, and a switch means 16 is electrically connected to a primary winding 15a of the switching transformer 15, and a first rectifying means 17, which is a rectifying means, is electrically connected to a first secondary winding 15b1 of the switching transformer 15. A half-wave rectifying element such as a diode is used for the first rectifying means 17. A first smoothing means 18, which is a smoothing means, and the charging circuit 7 are electrically connected to the output side of the first secondary winding 15b1 of the first power conversion circuit 5, i.e., the first rectifying means 17. The primary winding 15a of the switching transformer 15 is electrically connected to the output side of the primary side smoothing means 13, and one secondary winding 15b1 set to a predetermined one turn ratio with respect to the primary winding 15a is electrically connected to the charging circuit 7. In this embodiment, the first power conversion circuit 5 steps down the received voltage and outputs it by the switching transformer 15. For example, an IPD circuit or the like is used as the switching means 16. The switching of the switching means 16 is controlled by a first control unit (not shown) which is a control unit. The first control unit is connected to the one secondary winding 15b1 of the switching transformer 15 in an insulated state using a photocoupler or the like. In this embodiment, the first control unit is electrically connected to, for example, a detection circuit which feeds back the electrical characteristics of the secondary side of the switching transformer 15, and controls the switching of the switching means 16 so that the output voltage of the first power conversion circuit 5 becomes a predetermined constant voltage.

[0014] A smoothing element such as an electrolytic capacitor is used as the first smoothing means 18. The first smoothing means 18, the charging circuit 7, and the second power conversion circuit 8 are electrically connected to the cathode side of the first rectifying means 17.

[0015] The charging circuit 7 is a circuit that charges the secondary battery 6 from one secondary winding 15b1 of the switching transformer 15. The charging circuit 7 is configured, for example, by electrically connecting a resistor, which is a current setting means for setting the charging current of the secondary battery 6, and the secondary battery 6 in series. The charging circuit 7 is a constant current circuit that charges the secondary battery 6 at a constant current by the charging current set by the resistor. In addition, in the charging circuit 7, a first switch, which is a switching means, is electrically connected to a connection point between the resistor and the secondary battery 6. In addition, a second switch, which is a switching means, is electrically connected in parallel to the resistor and the first switch. The second switch is electrically connected to a connection point between the first switch and the secondary battery 6. The first switch is turned on when the input voltage 9 is input, and the second switch is turned on when the input voltage 9 is not input, that is, when the secondary battery 6 is discharged. In other words, the first switch and the second switch constitute a selection means that is selectively switched depending on whether the input voltage 9 is input or not. The first switch is a means for disconnecting the secondary battery 6 from the charging circuit 7. The charging circuit 7, the first switch, and the second switch form a charging / discharging circuit.

[0016] In this embodiment, the second power conversion circuit 8 is electrically connected to the output side of the first power conversion circuit 5. The second power conversion circuit 8 has a charging circuit 7, i.e., a secondary battery 6, on the input side. In the illustrated example, the second power conversion circuit 8 acts as a lighting circuit (a constant lighting circuit and an emergency lighting circuit) that supplies power to the light source 3 regardless of whether the input voltage 9 is input or not. The second power conversion circuit 8 is a discharge circuit that includes at least one switching element 20 and converts the input voltage by the switching operation of the switching element 20. In this embodiment, the voltage of the secondary battery 6 is set lower than the forward voltage of the light source 3 (the voltage obtained by adding up the forward voltages of the individual light sources 3), so the second power conversion circuit 8 is a boost circuit. As an example of the boost circuit, a boost chopper circuit is used in this embodiment. That is, in the second power conversion circuit 8, a series circuit of an inductor 21 and a switching element 20 is electrically connected to the output side of one first smoothing means 18, and a second rectification means 22, which is a rectification means, is electrically connected in parallel to the switching element 20. A half-wave rectifying means such as a diode is used as the second rectifying means 22. The light source module 4 is electrically connected to the output side of the second power conversion circuit 8 via a second smoothing means 24 which is a smoothing means. A smoothing element such as an electrolytic capacitor is used as the second smoothing means 24.

[0017] The switching of the switching element 20 is controlled by a second control unit 25 which is a control unit. The second control unit 25 controls the switching of the switching element 20 according to the current flowing through the light source 3, regardless of whether the input voltage 9 is being input or not. For example, the second control unit 25 switches the switching element 20 at a predetermined switching frequency. The switching frequency is set to, for example, 250 kHz. In addition, the second control unit 25 controls the charging and discharging of the secondary battery 6 by the charging circuit 7 by switching the first switch and the second switch on and off according to the presence or absence of the input voltage 9. A FET or the like is used as the switching element 20.

[0018] The second control unit 25 generates power from the power obtained from the output side of the first power conversion circuit 5, i.e., the other secondary winding 15b2 of the switching transformer 15, the secondary battery 6, and the output side of the second power conversion circuit 8, by the power supply regulator 26. That is, when the input voltage 9 is input, the second control unit 25 obtains power from the first power conversion circuit 5 via the other secondary winding 15b2, and when the input voltage 9 is not input, obtains power from the secondary battery 6 or the second power conversion circuit 8. The power supply regulator 26 is electrically connected to the other secondary winding 15b2 of the first power conversion circuit 5, the secondary battery 6, and the output side of the second power conversion circuit 8 via protection means 27, 28, and 29, respectively. A three-terminal regulator or the like is used as the power supply regulator 26. Protection elements such as diodes are used as the protection means 27, 28, and 29.

[0019] Here, the other secondary winding 15b2 of the switching transformer 15 is a secondary winding dedicated to obtaining power from the second control unit 25. The other secondary winding 15b2 is set to a predetermined other winding ratio different from the predetermined one winding ratio with respect to the primary winding 15a. The winding ratio of the other secondary winding 15b2 is set to be smaller than the winding ratio of the one secondary winding 15b1, so that the output voltage is smaller than that of the one secondary winding 15b1. The winding ratio of the other secondary winding 15b2 is determined according to the power supply voltage of the second control unit 25 that is set in advance. The output voltage from the other secondary winding 15b2 is set to a voltage close to the power supply voltage of the second control unit 25 and lower than the voltage of the secondary battery 6. The other secondary winding 15b2 is electrically connected to the other first rectifying means 31, which is a rectifying means. A half-wave rectifying element such as a diode is used as the other first rectifying means 31. Further, to the output side of the other secondary winding 15b2 of the first power conversion circuit 5, that is, the other first rectifying means 31, another first smoothing means 32 which is a smoothing means is electrically connected.

[0020] A smoothing element such as an electrolytic capacitor is used as the other first smoothing means 32. The power supply regulator 26 is electrically connected to the cathode side of the other first rectifying means 31 via the other first smoothing means 32 and the protection means 27.

[0021] In the above-mentioned lighting device 1, when the input voltage 9 is input, that is, always, in other words, when the lighting device 1 is operated by the input voltage 9, the first switch is turned on and the second switch is turned off in the power supply device 2 by the second control unit 25 that receives power from the other secondary winding 15b2 of the switching transformer 15 of the first power conversion circuit 5 via the power regulator 26, and in the first power conversion circuit 5, the first control unit switches the switch means 16 so that the output voltage of the first power conversion circuit 5 becomes a predetermined constant voltage. In the charging circuit 7 whose operation is controlled by the second control unit 25, the secondary battery 6 is charged with a constant charging current set by a resistor. In the second power conversion circuit 8 whose operation is controlled by the second control unit 25, the second control unit 25 detects the current flowing in the light source module 4, i.e., the light source 3, switches the switching element 20 so that this current is constant, and supplies power to the light source module 4, i.e., the light source 3, via the second rectifying means 22 and the second smoothing means 24, thereby turning on the light source 3. As a result, the second power conversion circuit 8 acts as a boost chopper circuit. In this way, by keeping the current of the light source 3 constant, the output voltage of the second power conversion circuit 8 is controlled to be approximately constant as the forward voltage of the light source 3, which in this embodiment is the LED, and the second power conversion circuit 8 acts as a constant voltage source.

[0022] Thus, according to one embodiment, in a power supply device 2 for a lighting device 1 having a first power conversion circuit 5 having a switching transformer 15, the power supply for the second control unit 25 for controlling the second power conversion circuit 8 is taken from another secondary winding 15b2 different from the one secondary winding 15b1 of the switching transformer 15 which serves as the power supply for the charging circuit 7 which charges the secondary battery 6. By bringing the voltage output from the other secondary winding 15b2 closer to the power supply voltage of the second control unit 25, losses in the power supply regulator 26 of the second control unit 25 can be suppressed, and power consumption can be suppressed.

[0023] Furthermore, a three-terminal regulator is usually used as the power supply regulator 26, but since a three-terminal regulator is a heat-generating component that generates more heat the greater the difference between the input voltage and the output voltage, by bringing the input voltage from the other secondary winding 15b2 of the switching transformer 15 closer to the power supply voltage of the second control unit 25 as described above, it is possible to suppress heat generation in the power supply regulator 26 and reduce the temperature of the power supply device 2. As a result, restrictions on component layout and integration on the circuit board due to heat generation are less likely to be imposed, improving the degree of freedom in layout, and enabling higher density and miniaturization.

[0024] In particular, in the case of a power supply device 2 in which the power supply voltage of the second control unit 25 is lower than the voltage of the secondary battery 6, in the conventional example in which the secondary winding of the switching transformer 15 is made into a single system and used as a power supply for charging the secondary battery 6 by the charging circuit 7 and as a power supply for the second control unit 25, the voltage drop in the power supply regulator 26 of the second control unit 25 becomes large, resulting in large losses. In contrast, in this embodiment, by setting up another secondary winding 15b2 dedicated to obtaining the power supply voltage for the second control unit 25, losses in the second control unit 25 can be suppressed.

[0025] Furthermore, when the input voltage 9 is constantly being input, the power consumption of the power supply device 2 is mainly due to the power required by the charging circuit 7 and its load, the secondary battery 6, but the power consumption of the second control unit 25 itself also accounts for a large proportion. Therefore, by suppressing the power consumption of the second control unit 25 as described above and making the power consumption of the power supply device 2 2 W or less, the power supply device 2 is considered to be a device that does not require measurement of harmonic current in the input current harmonic standard for lighting fixtures, which is advantageous in applying the harmonic standard when, for example, a lighting fixture is constructed by combining multiple power supply devices 2.

[0026] When the input voltage 9 is not being input, that is, during an emergency, in other words, during a power outage, in the power supply device 2, the first power conversion circuit 5 does not operate, and the second control unit 25, which takes power from the secondary battery 6 via the power regulator 26, turns off the first switch and turns on the second switch, thereby discharging the secondary battery 6 to the second power conversion circuit 8. In the second power conversion circuit 8, the second control unit 25 detects the current flowing through the light source module 4, i.e., the light source 3, switches the switching element 20 so that this current becomes constant, and supplies power to the light source module 4, i.e., the light source 3, via the second rectification means 22 and the second smoothing means 24. As a result, the second power conversion circuit 8 acts as a boost chopper circuit.

[0027] In this way, when the input voltage 9 is not being input, the second control unit 25 obtains power from the voltage of the secondary battery 6 or the boosted voltage of the secondary battery 6. Therefore, even if the input voltage 9 is not input and the output of the first power conversion circuit 5 cannot be secured, the second control unit 25 can continue to operate by drawing power from the secondary battery 6.

[0028] In the above embodiment, the power consumption may be set to 2 W or less by intermittently controlling the charging of the secondary battery 6 in the charging circuit 7 by the second control unit 25.

[0029] The above-described power supply device 2 can also be applied in the same manner to the case where the lighting device 1 is an emergency light in which the second power conversion circuit 8 turns on the light source 3 only when the input voltage 9 is not being input.

[0030] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0031] 2 Power supply 5 First power conversion circuit 6. Secondary batteries, which are storage batteries 7 Charging circuit 8 Second power conversion circuit 9 Input voltage 15 Switching transformer 15b1 One secondary winding 15b2 Other secondary windings 25 Second control section which is the control section

Claims

1. a first power conversion circuit having a switching transformer and receiving an input voltage; a charging circuit for charging a storage battery from one secondary winding of the switching transformer; a control unit that obtains power from another secondary winding different from the one secondary winding of the switching transformer when the input voltage is input; A second power conversion circuit whose operation is controlled by the control unit; The control unit controls charging of the storage battery in the charging circuit intermittently so that power consumption is 2 W or less. A power supply device comprising:

2. The power supply voltage of the control unit is lower than the voltage of the storage battery.

2. The power supply device according to claim 1.

3. The control unit obtains power from the voltage of the storage battery or the boosted voltage of the storage battery when the input voltage is not being input.

3. The power supply device according to claim 1 or 2.

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