JP2009284556A - Power supply circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply circuit in which power consumption in standby state is substantially reduced. <P>SOLUTION: The power supply circuit for supplying a load with power during stand-by time includes: a first rectifying section 33 for rectifying alternating current output having a first voltage value into a direct current and supplying the direct current to a load; a second rectifying section 34 for rectifying an alternating current output having a second voltage value higher than the first voltage value into a direct current and supplying the direct current to the load; an electric storage section 3 arranged between the first rectifying section 33 and the second rectifying section 34, which are arranged in parallel, and the load; and a switching section 4 for switching the connection of the load with either the first rectifying section 33 or the second rectifying section 34 by connecting or disconnecting the second rectifying section 34 to and from the load depending on a voltage formed by the electric storage section 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power supply circuit for electrical / electronic devices, and more particularly to a power supply circuit for electrical / electronic devices capable of reducing power consumption during standby.

  Many electrical and electronic devices such as video equipment and audio equipment are capable of remote operation by a remote controller and automatic time control by a timer. When power is turned on / off by remote operation or automatic time control, standby power supply for remote operation control or automatic time control is required even when the power is off. Examples of the places where such standby power supply is required include a remote controller light receiving unit and a control microcomputer.

  In recent years, in response to demands for energy savings, a main power supply circuit that supplies power when the equipment is in operation and a standby power supply circuit that supplies power when the equipment is in standby are provided separately in order to reduce power consumption when the equipment is on standby. The mainstream is a method of reducing the load on the device side during standby to the minimum necessary (see, for example, Patent Documents 1 to 3). The main power supply circuit has a main transformer, and the standby power supply circuit has a standby transformer having a lower capacity than the main transformer. Switching between the standby power supply circuit and the main power supply circuit is performed by a relay circuit. Since a low-capacity standby transformer is used during standby, power saving during standby can be achieved.

JP 2000-184719 A JP 2001-145354 JP 2002-112456 JP

  In the configuration including the standby power supply circuit, power supply to the remote controller light receiving unit, control microcomputer, and the like during standby and power supply to the relay circuit during operation power supply are performed by a standby transformer. For this reason, the secondary side voltage and the rated current of the standby transformer are designed according to the driving voltage of the relay, and cannot be made lower than this.

  As described above, since the setting of the secondary output voltage of the standby transformer is limited, the conventional configuration has a limit in reducing power consumption during standby. That is, since it is necessary to use a standby transformer having a relatively large secondary side output voltage, there is a limit to reducing the loss of the standby transformer itself and reducing the power consumption during standby. An object of the present invention is to solve the above-mentioned drawbacks in the prior art.

  In order to achieve the above object, a power circuit according to an aspect of the present invention is a power supply circuit that supplies power to a load during standby, and rectifies an AC output having a first voltage value into DC and supplies the DC power to the load. A first rectification unit; a second rectification unit that rectifies an alternating current output having a second voltage value higher than the first voltage value into a direct current and supplies the direct current to a load; and the first rectification unit provided in parallel And a power storage unit disposed between the rectifying unit and the second rectifying unit and the load, and connecting or disconnecting the second rectifying unit and the load according to a voltage formed by the power storage unit. And a switching unit that switches the connection between the first rectification unit and the load of the second rectification unit.

  The power supply circuit having the above configuration may include a transformer having an intermediate tap, the first rectifier receives an AC output when the transformer is connected to the intermediate tap, and the second rectifier is connected to both ends of the transformer. You may receive the alternating current output at the time of tap connection.

  In the power supply circuit having the above configuration, the first rectification unit and the second rectification unit may receive AC output from transformers having different capacities.

  In the above configuration, the switching unit includes a backflow preventing rectifier element provided between the first rectifier unit, the second rectifier unit, and the power storage unit.

  According to the present invention, a power supply circuit in which power consumption during standby is substantially reduced is provided.

  Hereinafter, a power supply circuit according to an embodiment of the present invention will be described in detail with reference to the drawings. The power supply circuit according to this embodiment is provided in an electric / electronic device such as a video device or an audio device. In addition, the example shown below is an example and this invention is not limited to this.

  A configuration of a power supply circuit according to the present embodiment is shown in FIG. A power supply circuit 100 shown in FIG. 1 includes a main power supply circuit 110, a standby power supply circuit 120, and a relay unit 130.

  The main power supply circuit 110 is connected to a power supply 111 such as a commercial power supply, and supplies power necessary for the operation of the main circuit 112 in a state where the power supply 111 of the device is turned on (during normal operation). The main circuit 112 constitutes a circuit for controlling the normal operation of the electric / electronic device.

  The standby power supply circuit 120 is connected to a power supply 111 such as a commercial power supply, and supplies necessary power to the load 121 in a state where the power supply 111 of the device is turned on. The load 121 is configured by any one or a combination of a microcomputer power source, a timer, a light receiving element for remote operation, a light emitting element, and the like that operate when the electric / electronic device is on standby.

  The relay unit 130 includes a relay coil power supply 132 that drives opening and closing of the contact 131 of the primary switching relay, and switches the power supply destination from the power supply 111 between the main power supply circuit 110 and the standby power supply circuit 120. During normal operation of the device (primary cut-off switch closed state), the primary cut-off relay contact 131 is closed, and when the device is on standby (primary cut-off switch open state), the primary cut-off relay contact 131 is open.

  The relay unit 130 is switched in accordance with, for example, a standby switch (or power supply by remote operation) off of the device, an instruction from a microcomputer using a button or the like. When the relay contact 130 is instructed to turn on the power, the relay unit 130 connects the power supply 111 to the main power supply circuit 110 when the relay contact 131 is closed, and connects the power supply 111 to the standby power supply when the relay contact 131 is open. Connect to circuit 120. The power consumption when the standby power supply circuit 120 is connected is smaller than the power consumption when the main power supply circuit 110 is connected. Therefore, the device is in the low power consumption mode during standby.

Hereinafter, the standby power supply circuit 120 according to the present embodiment will be described in detail.
FIG. 2 shows an example of the configuration of the standby power supply circuit 120. A standby power supply circuit 120 shown in FIG. 2 includes a standby transformer 5, a first rectifying unit 33, a second rectifying unit 34, a switching unit 4, and a power storage unit 3.

  The standby transformer 5 includes an intermediate tap 8 provided between both end taps, and the primary side is connected to the power source 111. The secondary output voltage value when the both-end taps of the standby transformer 5 are used is set to a value required to drive at least the relay unit 130 stably. The secondary side output voltage value when the intermediate tap 8 of the standby transformer 5 is used is a voltage value lower than the secondary side output voltage value when both end taps are used, and is set to the minimum necessary value for standby operation. Has been.

The first rectification unit 33 and the second rectification unit 34 rectify the secondary side AC output of the standby transformer 5 into a direct current. The first rectification unit 33 and the second rectification unit 34 are connected to the load 121.
The first rectifier 33 includes a diode 10 and a smoothing capacitor 12 connected to the secondary output tap and the intermediate tap 8 of the standby transformer 5. The first rectification unit 33 rectifies the secondary output when the intermediate tap 8 of the standby transformer 5 is used into direct current.
The second rectifying unit 34 includes a diode 11 and a smoothing capacitor 13 connected to both end taps of the secondary output of the standby transformer 5. The second rectifier 34 rectifies the secondary AC output when the both-end taps of the standby transformer 5 are used to DC.
The second rectifier 34 is connected to the NPN transistor 15 or the PNP transistor 14 for opening and closing with the subsequent stage.

  The switching unit 4 has a function of switching the output from the first rectifying unit 33 and the second rectifying unit 34 to any one, and includes a flip-flop circuit that is driven by a negative trigger pulse. The switching unit 4 connects or disconnects the second rectification unit 34 and the load 121 according to a voltage value formed by the power storage unit 3 to be described later, so that the first rectification unit 33 and the second rectification unit 34 The connection with the load 121 is switched to either one.

  The switching unit 4 includes a flip-flop circuit trigger transistor 26 (PNP transistor), a transistor 27 (NPN transistor), a flip-flop circuit output transistor 17 (NPN transistor), an output transistor 18 (NPN transistor), and a rectifying element for backflow prevention. Diodes 19 to 22 are provided. The drive unit 16 of the NPN transistor 15 and the PNP transistor 14 is connected to the output of the transistor 17 constituting the flip-flop circuit. The outputs of the first rectifier 33 and the second rectifier 34 are connected to a stabilizing regulator via diodes 19 to 22 as rectifiers for backflow prevention.

  The power storage unit 3 includes a capacitor, a storage battery, and the like. The power storage unit 3 is connected to the input side of the stabilization regulator 23. The bases of the transistors 26 and 27 constituting the flip-flop circuit of the switching unit 4 are connected to the positive electrode side of the power storage unit 3 via the Zener diodes 24 and 25. The Zener voltage of the Zener diode 25 is set higher than the Zener voltage of the Zener diode 24.

  The standby operation of standby power supply circuit 120 according to the present embodiment will be described below.

  When the standby power supply circuit 120 is first connected to the power supply 111, charging of the power storage unit 3 from the first rectifying unit 33 using the intermediate tap 8 is started at the beginning of connection. At the time when the power supply 111 and the standby power supply circuit 120 are connected, the voltage between the GND (ground) of the power storage unit 3 is zero potential, so that both the voltage lower limit detection zener diode 24 and the voltage upper limit detection zener diode 25 are It becomes interception.

  Therefore, the flip-flop circuit trigger transistor 26 is turned on, the transistor 27 is turned off, the flip-flop circuit output transistor 17 is turned on, and the output transistor 18 is turned off. In a state where the flip-flop circuit output transistor 17 is turned on and the output transistor 18 is also cut off, the transistor 16 is turned on, and the transistor 14, the transistor 28, and the transistor 15 are turned on.

  When the transistor 14 and the transistor 15 are turned on, the second rectifier 34 using both end taps of the standby transformer 5 is connected to the load 121 via the regulator 23 for stabilization. At this time, the output voltage from the first rectifying unit 33 using the intermediate tap 8 of the standby transformer 5 is higher than the output voltage of the second rectifying unit 34 using the both end taps of the standby transformer 5, so Blocked by the prevention diodes 19 and 20.

  As described above, after the power is turned on, the switching unit 4 connects the second rectifying unit 34 using the both end taps and the load 121 in a state where the GND voltage of the power storage unit 3 is low.

  In this state, the power storage unit 3 is charged via the second rectification unit 34 using both end taps of the standby transformer 5. When charging of the power storage unit 3 proceeds to form a GND voltage with respect to a voltage exceeding a predetermined voltage value (the Zener voltage of the Zener diode 24), the voltage lower limit value detecting Zener diode 24 becomes conductive, but the voltage upper limit value detecting voltage is detected. Since the Zener diode 25 is set higher than the Zener diode 24 for detecting the voltage lower limit value, the Zener diode 25 maintains the cut-off state. When the voltage lower limit detection zener diode 24 becomes conductive, the flip-flop circuit trigger transistor 26 is cut off, but the flip-flop circuit reacts with a negative trigger pulse, and therefore maintains the output state.

  When the power storage unit 3 is further charged and the voltage between the power storage unit 3 and GND exceeds a predetermined voltage value (the Zener voltage of the Zener diode 25), the voltage upper limit value follows the voltage lower limit value detection Zener diode 24. The detection Zener diode 25 becomes conductive. When the voltage upper limit detection zener diode 25 is turned on, the transistor 27 is turned on, the flip-flop circuit output transistor 17 is cut off, and the output transistor 18 is turned on.

  When the flip-flop circuit output transistor 17 is cut off and the output transistor 18 is turned on, the transistor 16 is cut off, so that the transistor 14, the transistor 28, and the transistor 15 are cut off. Further, when the transistor 29 is turned on, the transistor 30 is also turned on. As a result, the connection between the second rectifying unit 34 and the load 121 using both end taps of the standby transformer 5 is disconnected.

  As described above, the switching unit 4 establishes a connection between the second rectifying unit 34 and the load 121 when the GND voltage with respect to the power storage unit 3 exceeds a predetermined voltage value (the zener voltage of the zener diode 25). Separate.

  When the connection between the second rectifying unit 34 using the both-end taps of the standby transformer 5 and the regulator 23 for stabilization is disconnected, the voltage between the power storage unit 3 and GND uses the intermediate tap 8 of the standby transformer 5. Since the output voltage is higher than the output voltage from the first rectifier 33, the connection between the first rectifier 33 and the load 121 is blocked by the backflow prevention diodes 19 and 20.

  However, even in the standby state, since the microcomputer, the light receiving element, and the light emitting element are lit as the load 121, the charge charged in the power storage unit 3 is discharged by the load current, and the voltage between the power storage unit 3 and the GND is gradually increased. descend.

  The electric charge charged in the power storage unit 3 is discharged by the load current at the time of standby, and the voltage between the power storage unit 3 with respect to GND advances, and the voltage between the power storage unit 3 with respect to GND becomes lower than the voltage upper limit detection zener diode 25. When the voltage falls below the zener voltage, the voltage upper limit value detecting zener diode 25 is cut off, and the flip-flop circuit trigger transistor 27 is also cut off. However, since this flip-flop circuit reacts with a negative trigger pulse, the second rectifier 34 and the load 121 are not connected.

  Further, since the Zener voltage of the voltage lower limit value detecting Zener diode 24 is set to be lower than the Zener voltage of the voltage upper limit value detecting Zener diode 25, the voltage lower limit value detecting Zener diode 24 remains in a conductive state. The flip-flop circuit trigger transistor 26 also maintains the cut-off state.

  Further, when the voltage to GND of the power storage unit 3 decreases and the voltage value of the first rectification unit 33 exceeds the voltage of the power storage unit 3, the first rectification unit 33 is connected to the load side. At this time, power is supplied from the power storage unit 3 and the first rectification unit 33 to the load side. The voltage value of the first rectifying unit 33 is set based on the voltage value lower limit value necessary for stabilization and the time until switching to both end taps.

  As described above, in a state where the GND voltage with respect to the power storage unit 3 is higher than the Zener voltage of the Zener diode 24, the switching unit 4 disconnects the second rectifying unit 34 and the load 121 to connect the power storage unit 3 to the load 121. Alternatively, power is supplied from the power storage unit 3 and the first rectification unit 33.

  When the discharge of the power storage unit 3 further proceeds and the voltage between the power storage unit 3 and GND falls below the Zener voltage of the voltage lower limit value detection Zener diode 24, the voltage lower limit value detection Zener diode 24 shifts to the cutoff state, and the flip-flop The circuit trigger transistor 26 becomes conductive. When the flip-flop circuit trigger transistor 26 is turned on, the state of the flip-flop circuit is shifted, and the second rectifier 34 and the load 121 are connected as described above.

  During the subsequent standby, as described above, the rectification at both end taps of the standby transformer 5 to the rectification at the intermediate tap 8 is repeated. In the standby state, the both-end taps and the intermediate taps 8 of the standby transformer 5 of the standby power supply circuit 120 are alternately selected by the voltage between the power storage unit 3 and GND.

  As described above, in the present embodiment, the standby power supply 111 transformer including the intermediate tap 8, the second rectification unit 34 using both-end taps, the first rectification unit 33 using the intermediate tap 8, and the load The switching unit 4 that switches the connection to the power supply 121 and the power storage unit 3 for supplying power for supplementarily supplying power during standby are provided.

  The standby power supply circuit 120 monitors the output-side voltage of the standby power supply circuit 120 by supplying power to the load 121 side, and when the voltage value exceeds a predetermined value, the standby power supply circuit 120 is connected between the second rectifying unit 34 and the load 121. The connection is switched between the first rectifying unit 33 and the load 121 by disconnecting the connection. By switching to the intermediate tap 8, the loss on the secondary side of the transformer is reduced. Further, in a state where the potential formed by the power storage unit 3 is higher than the output voltage of the first rectification unit 33, the first rectification unit 33 and the load 121 are disconnected, and the load 121 receives power from the power storage unit 3. Is supplied. For this reason, power consumption during standby is suppressed.

  FIG. 3 shows the time change of the secondary side voltage during standby, and FIG. 4 shows the time change of standby power during standby. As shown in FIG. 3, at the time of standby, the secondary output voltage increases until reaching a predetermined upper limit value Va in a state where both-end tap connection of the standby transformer 5 is selected (state I). At this time, electric charge is stored (charged) in the power storage unit 3 up to its maximum capacity.

  When the voltage Va is reached, the tap connection at both ends is disconnected, and power is supplied from the power storage unit 3 to the load 121. As the power storage unit 3 is discharged, the secondary voltage gradually decreases (state II). At this time, the power supply from the standby transformer 5 to the load 121 is cut off by the GND voltage with respect to the power storage unit 3. Therefore, the power consumption of the device during this period is only the loss of the transformer as shown in FIG.

  Thereafter, when the voltage between the power storage unit 3 and GND decreases further with the passage of time due to power consumption at the load 121 and becomes equal to or lower than the predetermined value Vc, the power supply 111 required for the load 121 is not only the power storage unit 3 but also the intermediate It is complemented also from the tap 8 (FIG. 3, state III). Therefore, the power consumption of the device during this period is the loss of the transformer and the amount of power supplied from the intermediate tap 8, as shown in FIG.

  Further, when the GND voltage with respect to the power storage unit 3 decreases and reaches the tap switching voltage lower limit value Vb, the switching unit 4 switches to the both-end tap connection of the standby transformer 5. Here, the lower limit value Vb of the tap switching voltage is set based on the minimum voltage value necessary for stabilizing the rectified voltage, and the secondary side power consumption value (load current × voltage) is maximized. It is set to a value that can be reduced. After switching to the tapped connection at both ends, the secondary side voltage starts to rise, and during this time, charge is accumulated in the power storage unit 3 again (FIG. 3, state I). Thereafter, standby power supply circuit 120 repeats states I to III.

  By repeating the above process, power consumption of the device can be reduced during standby. That is, in FIG. 4, when the intermediate tap 8 is not used, the power consumption is constant. However, in the present embodiment in which the intermediate tap 8 and the both end taps are periodically switched, the amount of power consumption indicated by the hatched portion is substantially reduced as compared with the case where the intermediate tap 8 is not used.

  The present invention is not limited to the above embodiment, and various modifications and the like are possible.

  For example, in the configuration shown in FIG. 3, as shown in FIG. 5, the switching of the rectifying unit of the standby transformer 5 may be performed by a switching circuit 150 including a microcomputer or the like. The switching circuit 150 switches the rectifier according to the secondary voltage value that changes according to the state of charge of the power storage unit 3.

  Further, without using the standby transformer 5 with the intermediate tap 8, as shown in FIG. 6, the standby transformers 5 having different rated capacities connected to the first rectifying unit 33 and the second rectifying unit 34 are separately provided. Also good. 6, the transformer 31 corresponds to when the intermediate tap 8 of the standby transformer 5 in FIG. 2 is connected, and the transformer 32 corresponds to when both ends of the standby transformer 5 in FIG. 2 are connected. Even with such a configuration, the same effect as described above can be realized.

It is a block diagram which shows the structure of the power supply circuit concerning embodiment of this invention. It is a block diagram which shows the structure of the standby power supply circuit concerning embodiment of this invention. It is a figure which shows the time passage of the secondary side voltage at the time of standby in embodiment of this invention. It is a figure which shows the time passage of the secondary side electric power at the time of standby in embodiment of this invention. It is a block diagram which shows the structure of the standby power supply circuit concerning other embodiment of this invention. It is a block diagram which shows the structure of the standby power supply circuit concerning other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100: Power supply circuit, 110: Main power supply circuit, 120: Standby power supply circuit, 130: Relay part, 121: Load, 132: Relay coil power supply, 5: Standby transformer, 33: 1st rectifier, 34: 2nd Rectification unit, 4: switching unit, 3: power storage unit

Claims (4)

A power supply circuit for supplying power to a load during standby,
A first rectifier that rectifies an alternating current output having a first voltage value into a direct current and supplies the direct current to a load;
A second rectification unit that rectifies an alternating current output having a second voltage value higher than the first voltage value into a direct current and supplies the direct current to a load;
A power storage unit disposed between the first rectification unit and the second rectification unit and a load provided in parallel;
Depending on the voltage formed by the power storage unit, the connection between the second rectification unit and the load is made by connecting or disconnecting the first rectification unit and the load of the second rectification unit. A switching unit for switching between
A power supply circuit comprising: With a transformer with an intermediate tap,
The first rectification unit receives an AC output when the transformer is connected to an intermediate tap, and the second rectification unit receives an AC output when the transformer is connected to both ends of the tap. The power supply circuit described.   2. The power supply circuit according to claim 1, wherein the first rectifying unit and the second rectifying unit receive AC outputs from transformers having different capacities.   The switching unit includes a backflow preventing rectifier element provided between the first rectifier unit, the second rectifier unit, and the power storage unit, respectively. The power supply circuit described in 1.

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