JP3674562B2 - Power supply device and power supply method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for supplying a DC power supply, and more particularly to a technique for suppressing fluctuations in the output DC voltage.
[0002]
[Prior art]
FIG. 2 is a circuit diagram showing a conventional technique, showing a DC voltage supply unit and a load that receives the DC voltage. Specifically, the DC voltage supply unit includes an AC power supply 9 and a DC power supply 10. The DC power supply 10 includes output terminals 11, 12, and 13 that supply a plurality of DC voltages V ₁ , V ₂ , and V ₃ , respectively.
[0003]
The output terminals 11, 12, and 13 function as power supply terminals 11a, 12a, and 13a to which loads are to be connected, respectively. As a customary description mode of the circuit diagram, the output terminals 11, 12, 13 and the power terminals 11a, 12a, 13a are illustrated apart from each other, but in reality, the output terminals 11, 12, 13 have power terminals 11a, 12a and 13a are respectively connected.
[0004]
One end of each of the loads 6, 51, 52 is connected to the power supply terminals 11 a, 12 a, 13 a, and DC voltages V ₁ , V ₂ , V ₃ are respectively applied to the ground.
[0005]
[Problems to be solved by the invention]
However, the size of the load that receives the DC voltage may be different. For example, taking an air conditioner as an example, a plurality of remote controllers may be provided according to the number of indoor units, and an adapter for performing remote monitoring and remote operation of the air conditioner may be provided. Speaking in accordance with FIG. 2, remote controllers 61 and 62 and an adapter 63 can be connected to the power supply terminal 11 a as the load 6. However, it is not always connected. In the figure, the remote controllers 61 and 62 and the adapter 63 are indicated by broken lines to indicate whether or not they are connected.
[0006]
On the other hand, there is an upper limit on the current capacity of the DC power supply. Accordingly, the supplied DC voltages V ₁ , V ₂ , and V ₃ can vary depending on the size of the load 6 even if the voltage of the AC power supply 9 does not vary. That is, as the load 6, when the remote control 61, 62 and the adapter 63 is connected, they are not only the DC voltages V ₁ obtained at the power supply terminal 11a to be connected, obtained from other power supply terminal 12a, 13a The DC voltages V ₂ and V ₃ are also lowered. Conversely, the smaller the number of remote controllers or the like connected to the load 6, the higher the DC voltages V ₁ , V ₂ , V ₃ .
[0007]
Since the loads 51 and 52 are connected to the power supply terminals 12 a and 13 a, the DC voltages V ₂ and V ₃ supplied to them depend on the size of the load 6. Therefore, in order to make the loads 51 and 52 exhibit their desired performance, troublesome adjustment according to the magnitude of the load 6 is performed.
[0008]
The present invention has been made in view of the above circumstances, and provides a technique for reducing the dependency of a voltage obtained from a certain power supply terminal on the magnitude of a load connected to another power supply terminal.
[0009]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a power supply device comprising a first output terminal (11, 11a) for outputting a _first DC voltage (V ₁ ) and a second DC voltage (V ₂ ; V ₃ ) is output only when the second output terminal (12, 12a; 13, 13a) and the load (61, 62, 63) are not connected to the first output terminal. And a dummy load (7) for drawing a dummy current from the output terminal.
[0010]
According to a second aspect of the present invention, there is provided the power supply device according to the first aspect, wherein the dummy load (7) is connected to the load (61, 62, 63) at the first output terminal. A switching element (71) that conducts only when not, and a load resistor (72) connected in series to the switching element (71).
[0011]
According to a third aspect of the present invention, there is provided the power supply device according to the second aspect, wherein the switching element (71) is received based on the determination signal (D) for determining whether or not the load is connected. The control part (8) which controls conduction | electrical_connection of is further provided.
[0012]
According to a fourth aspect of the present invention, the first output terminal (11, 11a) for outputting the _first DC voltage (V ₁ ) and the second DC voltage (V ₂ ; V ₃ ) are output. Only when a load (61, 62, 63) is not connected to the first output terminal with respect to a DC power supply (10) having a second output terminal (12, 12a; 13, 13a) In this method, a dummy current is drawn from the first output terminal.
[0013]
According to a fifth aspect of the present invention, there is provided a power supply method according to the fourth aspect, wherein a dummy load (7) is provided at the first output terminal, and the dummy load (7) is The switching element (71) and a load resistor (72) connected in series to the switching element (71), and the load (61, 62, 63) is connected to the first output terminal. Only conduct when not connected.
[0014]
According to a sixth aspect of the present invention, there is provided a power supply method according to the fifth aspect, wherein the switching element (71) is turned on based on a determination signal (D) for determining whether or not the load is connected. To control.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a circuit diagram showing a configuration of an embodiment of the present invention. An AC power supply 9 is input to the DC power supply 10 and DC voltages V ₁ , V ₂ and V ₃ are supplied to output terminals 11, 12 and 13, respectively. A dummy load 7 is connected between the output terminal 11 and the ground. However, the dummy load 7 may be connected between the output terminal 11 and another fixed potential.
[0016]
Although the output terminals 11, 12, and 13 and the power terminals 11a, 12a, and 13a are described separately, in reality, the power terminals 11a, 12a, and 13a are connected to the output terminals 11, 12, and 13, respectively. One end of each of the loads 51 and 52 is connected to the power supply terminals 12a and 13a, and the other end is grounded.
[0017]
As the load 6, remote controllers 61 and 62 and an adapter 63 can be connected to the power supply terminal 11a. However, it is not always connected. In the figure, the remote controllers 61 and 62 and the adapter 63 are indicated by broken lines to indicate whether or not they are connected.
[0018]
The dummy load 7 has a series connection of a switching element 71 and a load resistor 72. For example, a dummy current is drawn from the output terminal 11 in accordance with the opening / closing of the switching element 71. For example, a switching transistor can be used as the switching element 71.
[0019]
The switching element 71 conducts when none of the remote controllers 61 and 62 and the adapter 63 are connected as the load 6, and does not conduct if any one is connected. The control of the switching element 71 is performed by the control unit 8. That is, the control unit 8 controls opening and closing of the switching element 71 based on the determination signal D. The determination signal D is a signal indicating a result of determining the first case where all of the remote controllers 61 and 62 and the adapter 63 are connected and the second case where any one of them is connected. The determination signal D can be generated using a known technique. Further, as the control unit 8, a microcomputer that controls the operation of the loads 51, 52, and 6 can be used.
[0020]
In the first case, a dummy current is drawn from the output terminal 11 via the dummy load 7. Therefore, the DC voltages V ₂ and V ₃ do not increase compared to the conventional technique shown in FIG. On the other hand, since the dummy current does not flow in the second case, the DC voltages V ₂ and V ₃ decrease as in the conventional technique.
[0021]
As described above, in the present invention, the difference in the amount of current flowing from the output terminal 11 between the case where the load is connected to the power supply terminal 11a connected to the output terminal 11 and the case where the load is not connected is reduced. can do. Therefore, the dependency of the DC voltages V ₂ and V ₃ obtained from the power supply terminals 12a and 13a on the size of the load 6 connected to the power supply terminal 11a can be reduced. As a result, the adjustment for causing the loads 51 and 52 to exhibit the desired performance becomes simple or unnecessary.
[0022]
【The invention's effect】
According to the power supply device according to claim 1 and the power supply method according to claim 4 of the present invention, between when the load is connected to the first output terminal and when not connected, The difference in the amount of current flowing from the first output terminal can be reduced. Therefore, the dependence of the second DC voltage obtained from the second output terminal on the magnitude of the load connected to the first output terminal can be reduced. As a result, adjustment for causing the load connected to the second output terminal to exhibit the desired performance is simple or unnecessary.
[0023]
According to the power supply device according to claim 2 and the power supply method according to claim 5 of the present invention, a dummy current is supplied from the first output terminal only when no load is connected to the first output terminal. Pull out. Thereby, the difference in the amount of current flowing from the first output terminal can be reduced between when the load is connected to the first output terminal and when the load is not connected.
[0024]
According to the power supply device according to claim 3 and the power supply method according to claim 6 of the present invention, based on whether or not a load is connected to the first output terminal, from the first output terminal Whether or not the dummy current is drawn is adopted.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an embodiment of the present invention.
FIG. 2 is a circuit diagram showing a conventional technique.
[Explanation of symbols]
7 Dummy load 9 AC power supply 10 DC power supply 11, 12, 13 Output terminals 11a, 12a, 13a Power supply terminals 51, 52, 6 Load 61, 62 Remote control 63 Adapter 71 Switching element 72 Load resistance D Determination signals V ₁ , V ₂ , V ₃ DC voltage

Claims (6)

A first output terminal (11, 11a) for outputting a _first DC voltage (V ₁ );
A second output terminal (12, 12a; 13, 13a) for outputting a _second DC voltage (V ₂ ; V ₃ );
A power supply apparatus comprising: a dummy load (7) that draws a dummy current from the first output terminal only when a load (61, 62, 63) is not connected to the first output terminal. The dummy load (7) is
A switching element (71) that conducts only when a load (61, 62, 63) is not connected to the first output terminal;
The power supply device according to claim 1, further comprising a load resistor (72) connected in series to the switching element (71). A control unit (8) which receives a determination signal (D) for determining whether or not the load is connected and controls the conduction of the switching element (71) based on the determination signal (D).
The power supply device according to claim 2, further comprising: A first output terminal (11, 11a) for outputting a _first DC voltage (V ₁ );
A second output terminal (12, 12a; 13, 13a) for outputting a _second DC voltage (V ₂ ; V ₃ );
For a DC power supply (10) comprising
A method of supplying power, wherein a dummy current is drawn from the first output terminal only when a load (61, 62, 63) is not connected to the first output terminal. A dummy load (7) is provided at the first output terminal;
The dummy load (7) has the switching element (71) and a load resistance (72) connected in series to the switching element (71),
The power supply method according to claim 4, wherein the switching element is made conductive only when a load (61, 62, 63) is not connected to the first output terminal. The power supply method according to claim 5, wherein the conduction of the switching element (71) is controlled based on a determination signal (D) for determining whether or not the load is connected.

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