Power supply device, and program for power supply device

Abstract

To solve the problem in which a control circuit erroneously determines an over-voltage.SOLUTION: A power supply device 10 comprises a pair of output terminals, a high-potential power supply line LA, a battery 11, a switch located on the high-potential power supply line LA, a power conversion circuit 13 located on the high-potential power supply line LA, a voltage detection unit 14, a current detection unit 15, and a control unit 20. The control unit 20 switches the switch to an off state, when a voltage value detected by the voltage detection unit 14 is a first threshold value or less, and a current value detected by the current detection value 15 is a first current threshold value or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power supply device and a program for the power supply device. [Background technology]

[0002] The battery protection circuit disclosed in Patent Document 1 includes a control circuit and a FET switch. The FET switch is located between the negative terminal of the battery and a ground output. The control circuit controls the on / off state of the FET switch. The control circuit determines an overvoltage on the battery based on a comparison with a reference voltage. If the control circuit determines an overvoltage, it switches the FET switch off. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-282153 Summary of the Invention [Problem to be solved by the invention]

[0004] In the battery protection circuit disclosed in Patent Document 1, there is a risk that the control circuit may erroneously determine an overvoltage in response to momentary fluctuations in the voltage between the battery terminals due to noise or the like. [Means for solving the problem]

[0005] In order to solve the above problem, the present invention provides a power supply device comprising a pair of output terminals, a power line connected to the output terminals, a battery capable of outputting power from the output terminal via the power line, a switch located on the power line, a power conversion circuit located on the power line and capable of converting and outputting an input voltage, a voltage detection unit that detects a voltage value output from the power conversion circuit, a current detection unit that detects a current value between the power conversion circuit and the output terminal, and a control unit that can control the switching between the on state and the off state of the switch, wherein the control unit switches the switch to the off state when the voltage value detected by the voltage detection unit is less than or equal to a predetermined voltage threshold and when the current value detected by the current detection unit is greater than or equal to a predetermined current threshold.

[0006] The present invention is also applicable to a power supply device comprising a pair of output terminals, a power supply line connected to the output terminals, a battery capable of outputting power from the output terminal via the power supply line, a switch located on the power supply line, a power conversion circuit located on the power supply line and capable of converting and outputting an input voltage, a voltage detection unit that detects a voltage value output from the power conversion circuit, a current detection unit that detects a current value between the power conversion circuit and the output terminal, and a control unit that can control the switching between the on state and the off state of the switch, and is a program for the power supply device that causes the control unit to switch the switch to the off state when the voltage value detected by the voltage detection unit is equal to or less than a predetermined voltage threshold and when the current value detected by the current detection unit is equal to or greater than a predetermined current threshold. [Effects of the Invention]

[0007] This can prevent the control circuit from erroneously determining that an overvoltage has occurred. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a circuit diagram of a power supply device. [Figure 2]FIG. 2 is a diagram showing changes in voltage and current under the first control. [Figure 3] FIG. 3 is a diagram showing changes in voltage and current under the second control. DETAILED DESCRIPTION OF THE INVENTION

[0009] <One embodiment of a power supply device and a program for the power supply device> An embodiment of a power supply device and a program for the power supply device will be described below. Note that the drawings are schematic diagrams for ease of understanding, and components may be enlarged or omitted. Therefore, the dimensional ratios of the components may differ from those of the actual components.

[0010] (Overall structure) As shown in FIG. 1, the power supply device 10 includes a battery 11, a high-potential power line LA, a low-potential power line LB, a high-potential output terminal 12A, a low-potential output terminal 12B, and a power conversion circuit 13.

[0011] The battery 11 is a secondary battery such as a lithium ion battery that can be charged and discharged. The battery 11 has a positive terminal 11A and a negative terminal 11B. The battery 11 can supply DC power to a load 40 connected to a high-potential output terminal 12A and a low-potential output terminal 12B. Although not shown, the high-potential output terminal 12A and the low-potential output terminal 12B may be connected to a power source such as another power supply device or power system connected in parallel to the load 40. In this case, the battery 11 can receive DC power from the power source connected to the high-potential output terminal 12A and the low-potential output terminal 12B.

[0012] The high-potential power supply line LA is a power supply line that connects the positive terminal 11A of the battery 11 and the high-potential output terminal 12A. That is, a first end of the high-potential power supply line LA is connected to the positive terminal 11A of the battery 11. A second end of the high-potential power supply line LA is connected to the high-potential output terminal 12A. The high-potential output terminal 12A can be connected to a load 40.

[0013] The low-potential power supply line LB is a power supply line connecting the negative terminal 11B of the battery 11 and the low-potential output terminal 12B. That is, a first end of the low-potential power supply line LB is connected to the negative terminal 11B of the battery 11. A second end of the low-potential power supply line LB is connected to the low-potential output terminal 12B. The low-potential output terminal 12B can be connected to a load 40. The potential of the low-potential output terminal 12B is set to ground potential. The load 40 operates on a DC voltage from the power supply device 10. The load 40 is, for example, a server or storage in a data center.

[0014] The power conversion circuit 13 is located on the high-potential power supply line LA. That is, the high-potential input terminal of the power conversion circuit 13 is connected to the positive terminal 11A of the battery 11. The high-potential output terminal of the power conversion circuit 13 is connected to the high-potential output terminal 12A.

[0015] The power conversion circuit 13 in this embodiment is a bidirectional DC-DC converter, and therefore includes an inductor and a MOSFET (Metal Oxide Semiconductor Field-Effect Transistor), both of which are not shown.

[0016] The power conversion circuit 13 can switch between a discharging state and a charging state under the control of the control unit 20, which will be described later. In the discharging state, a load 40 is connected to the high potential output terminal 12A and the low potential output terminal 12B, and power stored in the battery 11 is discharged to the load 40. In the discharging state, the power conversion circuit 13 transforms the voltage input from the battery 11 to a predetermined voltage for the load 40 and outputs the voltage. In the charging state, a power source is connected to the high potential output terminal 12A and the low potential output terminal 12B, and power is charged from the power source to the battery 11. In the charging state, the power conversion circuit 13 transforms the voltage input from the power source to a predetermined voltage for the battery 11 and outputs the voltage.

[0017] The power supply device 10 includes a first resistor R1, a first capacitor C1, a second resistor R2, and a second capacitor C2. The first resistor R1 is located on the high-potential power line LA. A first end of the first resistor R1 is connected to the positive terminal 11A of the battery 11. A second end of the first resistor R1 is connected to the input terminal of the power conversion circuit 13. A first end of the first capacitor C1 is connected to the second end of the first resistor R1 and the input terminal of the power conversion circuit 13. A second end of the first capacitor C1 is connected to the frame ground.

[0018] The second resistor R2 is located on the high-potential power supply line LA. A first end of the second resistor R2 is connected to the output terminal of the power conversion circuit 13. A second end of the second resistor R2 is connected to the high-potential output terminal 12A. A first end of the second capacitor C2 is connected to the first end of the second resistor R2 and the output terminal of the power conversion circuit 13. A second end of the second capacitor C2 is connected to the frame ground.

[0019] The power supply device 10 includes a first switch SW1 and a second switch SW2. The first switch SW1 and the second switch SW2 are both located on the high-potential power line LA and can be switched between an on state and an off state.

[0020] The first switch SW1 is located between the battery 11 and the power conversion circuit 13 on the high-potential power line LA. More specifically, a first terminal of the first switch SW1 is connected to the positive terminal 11A of the battery 11. A second terminal of the first switch SW1 is connected to the input terminal of the power conversion circuit 13 via a first resistor R1. Although not shown, the first switch SW1 is configured with one or more switching elements. An example of the switching element is an n-channel MOSFET.

[0021] The second switch SW2 is located on the high-potential power supply line LA between the power conversion circuit 13 and the high-potential output terminal 12A for the load 40. More specifically, a first terminal of the second switch SW2 is connected to the output terminal of the power conversion circuit 13 via a second resistor R2. A second terminal of the second switch SW2 is connected to the high-potential output terminal 12A. Although not shown, the second switch SW2 is configured with one or more switching elements. An example of the switching element is an n-channel MOSFET.

[0022] The power supply device 10 includes a voltage detection unit 14 and a current detection unit 15. The voltage detection unit 14 detects the voltage value output from the power conversion circuit 13. More specifically, a first terminal of the voltage detection unit 14 is connected to the output terminal of the power conversion circuit 13. A second terminal of the voltage detection unit 14 is connected to the low-potential power supply line LB. Therefore, the voltage detection unit 14 detects the potential difference between the potential of the high-potential power supply line LA converted by the power conversion circuit 13 and the ground potential of the low-potential power supply line LB as a voltage detection value Vd.

[0023] The current detection unit 15 detects the value of a current flowing between the power conversion circuit 13 and the high-potential output terminal 12A. More specifically, the current detection unit 15 detects the current flowing through the second resistor R2 as a current detection value id. A first terminal of the current detection unit 15 is connected to a first terminal of the second resistor R2. A second terminal of the current detection unit 15 is connected to a second terminal of the second resistor R2. The current detection unit 15 detects the value of a current flowing from the battery 11 side to the load 40 side as a positive value, and the value of a current flowing from the load 40 side to the battery 11 side as a negative value.

[0024] (Power supply circuit control unit and program) As shown in FIG. 1, the power supply device 10 includes a control unit 20. The control unit 20 acquires a voltage detection value Vd detected by the voltage detection unit 14. The control unit 20 acquires a current detection value id detected by the current detection unit 15. The control unit 20 can acquire the voltage detection value Vd and the current detection value id simultaneously. The control unit 20 also outputs a first control signal S1 for switching the first switch SW1 between an on state and an off state. The control unit 20 outputs a second control signal S2 for switching the second switch SW2 between an on state and an off state. The control unit 20 can also control the on state and the off state of the switching elements included in the power conversion circuit 13.

[0025] Although not shown, the control unit 20 includes a storage device and an arithmetic processing unit. That is, the control unit 20 is an MCU (Microcontroller Unit). The storage device stores various programs executed by the arithmetic processing unit. One of the programs is an abnormality detection program PG for detecting abnormalities in the voltage detection value Vd and the current detection value id. The arithmetic processing unit includes, for example, a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). Note that, hereinafter, the execution of the abnormality detection program PG and various controls by the arithmetic processing unit are simply referred to as execution and control by the control unit 20. The arithmetic processing unit is capable of executing the abnormality detection program PG. The abnormality detection program PG causes the control unit 20 to execute first, second, and third controls. In the first, second, and third controls, the control unit 20 performs threshold control using the voltage detection value Vd, the current detection value id, and predetermined thresholds. Note that the control unit 20 executes the first, second, and third controls simultaneously. In other words, the control unit 20 simultaneously performs judgments in each control.

[0026] (Regarding the first control of the anomaly detection program) When the power conversion circuit 13 is operating, the control unit 20 executes a first control of the abnormality detection program PG. In the first control, the control unit 20 performs threshold control using a predetermined first voltage threshold and a first current threshold. Note that when no abnormality is detected in any of the first control, second control, and third control, the first switch SW1 and the second switch SW2 are both in the on state.

[0027] When the control unit 20 executes the first control, it first determines whether the power conversion circuit 13 is being controlled in a discharging state or a charging state. When the power conversion circuit 13 is being controlled in a charging state, the control unit 20 sets the first current threshold to a larger value than when the power conversion circuit 13 is being controlled in a discharging state. For example, if the value of the first current threshold in the discharging state is −5 A, the control unit 20 sets the first current threshold in the charging state to −20 A. The first voltage threshold and first current threshold in the charging state and the first voltage threshold and first current threshold in the discharging state are stored in advance in a storage device of the control unit 20, for example.

[0028] Next, the control unit 20 simultaneously acquires the detected voltage value Vd and the detected current value id. Then, the control unit 20 determines whether the magnitude of the detected voltage value Vd is equal to or less than a predetermined first voltage threshold. The control unit 20 also determines whether the magnitude of the detected current value id is equal to or greater than a predetermined first current threshold. If one or more of the above two conditions are not satisfied, the control unit 20 repeatedly acquires the detected voltage value Vd and the detected current value id. If both of the above two conditions are satisfied, the control unit 20 determines that an abnormality has occurred. Then, the control unit 20 switches the first switch SW1 and the second switch SW2 to the OFF state.

[0029] Here, the "magnitude of the detected current value id" refers to the absolute value of the detected current value id. The "magnitude of the current threshold" refers to the absolute value of the current threshold. However, when determining whether the detected current value id is equal to or greater than the first current threshold, it is not necessary to actually use or calculate the absolute value of the detected current value id. In other words, when the detected current value id is a positive value, the control unit 20 only needs to determine whether the detected current value id is equal to or greater than the positive current threshold. When the detected current value id is a negative value, the control unit 20 only needs to determine whether the detected current value id is equal to or less than the negative current threshold. For example, even if the detected current value id is −5 A and the first current threshold is −4 A, the control unit 20 determines that the detected current value id is equal to or greater than the first current threshold. The same applies to the detected voltage value Vd and the voltage threshold. That is, when the detected voltage value Vd is a positive value, the control unit 20 only needs to determine whether the detected voltage value Vd is equal to or less than the positive voltage threshold. When the voltage detection value Vd is a negative value, the control unit 20 may determine whether the voltage detection value Vd is equal to or greater than a negative voltage threshold value.

[0030] (Regarding the second control of the anomaly detection program) When the power conversion circuit 13 is operating, the control unit 20 executes the second control of the abnormality detection program PG. In the second control, the control unit 20 performs threshold control using a predetermined second voltage threshold and second current threshold. When the control unit 20 starts the second control, it first determines whether the power conversion circuit 13 is being controlled in a discharging state or a charging state. When the power conversion circuit 13 is being controlled in a charging state, the control unit 20 sets the second current threshold to be larger than when the power conversion circuit 13 is being controlled in a discharging state. Note that the second voltage threshold and second current threshold in the charging state and the second voltage threshold and second current threshold in the discharging state are pre-stored in, for example, a storage device of the control unit 20. Furthermore, the second current threshold in the charging state is smaller than the first current threshold in the charging state, and the second current threshold in the discharging state is smaller than the first current threshold in the discharging state.

[0031] Next, the control unit 20 simultaneously acquires the detected voltage value Vd and the detected current value id. The control unit 20 then determines whether the magnitude of the detected voltage value Vd is equal to or less than the second voltage threshold. The control unit 20 also determines whether the magnitude of the detected current value id is equal to or greater than the second current threshold. The second voltage threshold is greater than the first voltage threshold used in the first control. As described above, the second current threshold is smaller than the first current threshold used in the first control. The control unit 20 then determines whether a state in which one or more of the above two conditions is satisfied has continued for a first predetermined time. The first predetermined time is, for example, 37.5 μs if the control unit 20 can acquire the detected voltage value Vd and the detected current value id approximately every 12.5 μs. That is, if a pair of the simultaneously acquired detected voltage value Vd and the detected current value id satisfies one or more of the two conditions three times in a row, the control unit 20 determines that the above state has continued for at least the first predetermined time. If the determination is positive, the control unit 20 determines that an abnormality has occurred, and then switches the first switch SW1 and the second switch SW2 to the OFF state.

[0032] Specifically, when the magnitude of the detected current value id is smaller than the second current threshold, the detected voltage value Vd becomes equal to or smaller than the second voltage threshold. In other words, at this point, one of the above two conditions is satisfied. Then, when the state in which the magnitude of the detected voltage value Vd is equal to or smaller than the second voltage threshold continues for a first predetermined time or longer, the control unit 20 switches the first switch SW1 and the second switch SW2 to the OFF state.

[0033] Furthermore, when the magnitude of the detected voltage value Vd is greater than the second voltage threshold, the magnitude of the detected current value id becomes equal to or greater than the second current threshold. In other words, at this point, one of the above two conditions is satisfied. Then, when the state in which the magnitude of the detected current value id is equal to or greater than the second current threshold continues for a first predetermined time or longer, the control unit 20 switches the first switch SW1 and the second switch SW2 to the OFF state.

[0034] On the other hand, suppose that the magnitude of the detected current value id becomes equal to or greater than the second current threshold while the detected voltage value Vd is greater than the second voltage threshold. However, suppose that the state in which the detected current value id becomes equal to or greater than the second current threshold is momentary and the time during which this condition is satisfied is shorter than the first predetermined time. In this case, the control unit 20 maintains the first switch SW1 and the second switch SW2 in the on state.

[0035] (Regarding the third control of the anomaly detection program) When the power conversion circuit 13 is operating, the control unit 20 executes the third control of the abnormality detection program PG. In the third control, the control unit 20 performs threshold control using a predetermined second voltage threshold and second current threshold. When the control unit 20 starts the third control, the control unit 20 first determines whether the power conversion circuit 13 is being controlled in a discharging state or a charging state. When the power conversion circuit 13 is being controlled in a charging state, the control unit 20 sets the second current threshold to be larger than when the power conversion circuit 13 is being controlled in a discharging state.

[0036] Next, the control unit 20 simultaneously acquires the detected voltage value Vd and the detected current value id. The control unit 20 then determines whether the magnitude of the detected voltage value Vd is equal to or less than the second voltage threshold. The control unit 20 also determines whether the magnitude of the detected current value id is equal to or greater than the second current threshold. The second voltage threshold is the same as the second voltage threshold in the second control. The second current threshold is the same as the second current threshold in the second control. The control unit 20 then determines whether the state in which both of the above two conditions are satisfied continues for a second predetermined time. The second predetermined time is, for example, 25 μs if the control unit 20 can acquire the detected voltage value Vd and the detected current value id approximately every 12.5 μs. In other words, the control unit 20 determines that the state in which the pair of the simultaneously acquired detected voltage value Vd and the detected current value id satisfy both of the two conditions has continued for more than the second predetermined time if the state occurs twice consecutively. If this determination is positive, the control unit 20 determines that an abnormality has occurred. Then, the control unit 20 switches the first switch SW1 and the second switch SW2 to the OFF state.

[0037] (Operation of this embodiment) As shown in FIG. 2, assume that at time t1, the output terminal of the power conversion circuit 13 is short-circuited to the low-potential power line LB. At this time, the voltage detection value Vd decreases. Furthermore, current flows toward the short-circuited location from the capacitor in the load 40 connected to the high-potential output terminal 12A and the power source connected to the high-potential output terminal 12A. As a result, the current detection value id increases. Then, assume that at time t2, the voltage detection value Vd becomes equal to or less than the first voltage threshold and the current detection value id becomes equal to or greater than the first current threshold. In this case, the control unit 20 switches the first switch SW1 and the second switch SW2 to the off state.

[0038] If a short circuit is determined based on only one of the detected voltage value Vd and the detected current value id, a momentary voltage fluctuation such as noise may cause the detected voltage value Vd to momentarily fall below the first voltage threshold. Therefore, the control unit 20 may erroneously determine a short circuit based on the momentary fluctuation of the detected voltage value Vd. However, if the control unit 20 determines a short circuit when it repeatedly detects that the detected voltage value Vd is below the first voltage threshold after time t2, the above-described erroneous determination can be reduced. However, this determination method requires a long time from the occurrence of a short circuit to the determination of the short circuit. In other words, the adverse effects of a short circuit may last for a long period of time.

[0039] In contrast, in the first control of this embodiment, the determination is made based on not only the detected voltage value Vd but also the detected current value id, which can suppress erroneous detection. Furthermore, since the determination is not made over a long period of time, the risk of the adverse effects of a short circuit lasting for a long period of time can be reduced.

[0040] As shown in FIG. 3, assume that a short circuit occurs in the second capacitor C2 at time t3. The more gradually the detected voltage value Vd and the detected current value id change, the longer the time it takes for the detected voltage value Vd to reach the first voltage threshold and the time it takes for the detected current value id to reach the first current threshold. In the second control of this embodiment, the second voltage threshold is set to a value greater than the first voltage threshold. The second current threshold is set to a value smaller than the first current threshold. If the detected voltage value Vd is equal to or less than the second voltage threshold at time t4, the control unit 20 turns off the first switch SW1 and the second switch SW2 if the detected voltage value Vd is equal to or less than the second voltage threshold between time t4 and time t5, a first predetermined time later. Since a similar determination is made for the detected current value id, the control unit 20 can prevent erroneous detection of a short circuit.

[0041] In the third control, when the voltage detection value Vd is equal to or less than the second voltage threshold and the current detection value id is equal to or greater than the second current threshold for a second predetermined time, the switches are turned off. This reduces false detections more effectively than the second control. Therefore, the second predetermined time is shorter than the first predetermined time.

[0042] (Effects of this embodiment) (1) In the above embodiment, the control unit 20 switches the first switch SW1 and the second switch SW2 to the OFF state when the magnitude of the voltage detection value Vd is equal to or less than the first voltage threshold and the magnitude of the current detection value id is equal to or greater than the first current threshold. As described above, this configuration can reduce erroneous determinations of a short circuit compared to determining based on either the voltage value or the current value alone. Furthermore, since a short circuit can be determined in a single determination rather than multiple determinations, the occurrence of a short circuit can be detected quickly. In other words, the above embodiment can reduce erroneous determinations while maintaining high-speed determination.

[0043] (2) In the above embodiment, the control unit 20 sets the first current threshold to be larger in the charging state in which power is supplied to the battery 11 from the pair of output terminals than in the discharging state in which power is supplied from the battery 11 to the pair of output terminals. In the charging state, a current flows from the high potential output terminal 12A side to the power conversion circuit 13 side. If a short circuit occurs in this state, the short circuit current is likely to be larger than in the discharging state. In consideration of this, by setting the first current threshold to a larger value in the discharging state, it is possible to improve the accuracy of determining whether an abnormality has occurred in the discharging state.

[0044] (3) In the above embodiment, the control unit 20 switches the first switch SW1 and the second switch SW2 to the off state when one or more of the following states continues for a first predetermined time: the magnitude of the voltage detection value Vd is equal to or less than the second voltage threshold; and the magnitude of the current detection value id is equal to or greater than the second current threshold. After a short circuit occurs, the voltage detection value Vd and the current detection value id may change gradually. In such a case, by performing a logical sum (OR) of the conditions related to each detection value, the control unit 20 can determine the existence of a short circuit relatively quickly while suppressing erroneous detection.

[0045] (4) In the above embodiment, the control unit 20 switches the first switch SW1 and the second switch SW2 to the off state when both the state in which the magnitude of the voltage detection value Vd is equal to or less than the second voltage threshold and the state in which the magnitude of the current detection value id is equal to or greater than the second current threshold continue for a second predetermined time. When the voltage detection value Vd and the current detection value id change gradually after a short circuit occurs, the control unit 20 can more easily suppress erroneous detection by determining the conditions related to each detection value using a logical product (AND).

[0046] <Example of change> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0047] The power supply device 10 may include multiple batteries 11. In this case, the multiple batteries 11 may be treated as a single DC power supply and the abnormality detection program PG may be applied to them, or the abnormality detection program PG may be applied to each of the multiple batteries 11.

[0048] The load 40 is not limited to the server, etc., exemplified in the above embodiment. The power source connected to the output terminal may be an inverter, etc. The power supply device 10 may include other elements such as fuses.

[0049] The power conversion circuit 13 is not limited to the example of the above embodiment. For example, instead of being a bidirectional converter, the power conversion circuit 13 may be composed of two converters: a boost converter that boosts the power from the battery 11, and a boost converter that boosts the voltage supplied from a power source connected to the output terminal.

[0050] The power supply device 10 may have only the first switch SW1 or only the second switch SW2. It is sufficient that the power supply device 10 has at least a switch that is located on the high-potential power line LA and that can be switched between an on state and an off state.

[0051] The configuration of each switch is not limited to the example in the above embodiment. It is sufficient that the on state and the off state can be switched by a control signal from the control unit 20. For example, each switch may include multiple switching elements connected in series or in parallel. Furthermore, the switching elements are not limited to N-type MOSFETs, but may also be P-type MOSFETs or other transistors.

[0052] The power supply device 10 may include a plurality of control units 20. For example, a control unit 20 may be provided for each switch. The values ​​of the first voltage threshold and the first current threshold do not have to be stored in advance in the storage device of the control unit 20. They may be set to arbitrary values ​​after the power supply device 10 is put into operation.

[0053] The control unit 20 only needs to switch one of the switches to the OFF state when at least the magnitude of the detected voltage value Vd is equal to or less than the first voltage threshold and the detected current value id is equal to or greater than the first current threshold. Therefore, in the first control, the control unit 20 may perform the above control only in the discharging state, or may perform the above control only in the charging state. Furthermore, the control unit 20 does not need to set the first current threshold to be higher in the charging state than in the discharging state. In other words, the magnitude of the first current threshold in the charging state may be equal to or less than the magnitude of the first current threshold in the discharging state. Furthermore, the control unit 20 may set the first voltage threshold to be lower in the charging state than in the discharging state.

[0054] <Additional Notes> The technical concepts that can be understood from the above-described embodiments and modifications will be described below. [1] A power supply device comprising: a pair of output terminals; a power supply line connected to the output terminals; a battery capable of outputting power from the output terminals via the power supply line; a switch located on the power supply line; a power conversion circuit located on the power supply line and capable of converting an input voltage and outputting the converted voltage; a voltage detection unit that detects a voltage value output from the power conversion circuit; a current detection unit that detects a current value between the power conversion circuit and the output terminals; and a control unit that can control switching between an on state and an off state of the switch, wherein the control unit switches the switch to an off state when the voltage value detected by the voltage detection unit is equal to or less than a predetermined voltage threshold and when the current value detected by the current detection unit is equal to or greater than a predetermined current threshold.

[0055] [2] The power supply device according to [1], wherein the control unit sets the current threshold to be larger in a charging state in which power is supplied from the output terminal to the battery than in a discharging state in which power is supplied from the battery to the output terminal.

[0056] [3] The power supply device according to [1] or [2], wherein when the voltage threshold is a first voltage threshold, the current threshold is a first current threshold, a threshold greater than the first voltage threshold is a second voltage threshold, and a threshold smaller than the first current threshold is a second current threshold, the control unit switches the switch to an off state when one or more of the following states continues for a predetermined period of time: the voltage value detected by the voltage detection unit is equal to or less than the second voltage threshold; and the current value detected by the current detection unit is equal to or greater than the second current threshold.

[0057] [4] A power supply device according to any one of [1] to [3], wherein when the voltage threshold is a first voltage threshold, the current threshold is a first current threshold, a threshold greater than the first voltage threshold is a second voltage threshold, and a threshold smaller than the first current threshold is a second current threshold, the control unit switches the switch to an off state when both of the following states continue for a predetermined period of time: the voltage value detected by the voltage detection unit is equal to or less than the second voltage threshold, and the current value detected by the current detection unit is equal to or greater than the second current threshold.

[0058] [5] A program for a power supply device that includes a pair of output terminals, a power line connected to the output terminals, a battery capable of outputting power from the output terminals via the power line, a switch located on the power line, a power conversion circuit located on the power line and capable of converting and outputting an input voltage, a voltage detection unit that detects a voltage value output from the power conversion circuit, a current detection unit that detects a current value between the power conversion circuit and the output terminals, and a control unit that can control the switching between the on state and the off state of the switch, the program causing the control unit to switch the switch to the off state when the voltage value detected by the voltage detection unit is equal to or less than a predetermined voltage threshold and the current value detected by the current detection unit is equal to or greater than a predetermined current threshold. [Explanation of symbols]

[0059] 10…Power supply device LA...High potential power line LB: Low potential power line 11...Battery 12A...High potential output terminal 12B: Low potential output terminal 13...Power conversion circuit 14...Voltage detection unit 15...Current detection section SW1: First switch SW2: Second switch 20...Control unit PG…Program 40...Load

Claims

1. a pair of output terminals; a power supply line connected to the output terminal; a battery capable of outputting power from the output terminal via the power supply line; a switch located on the power supply line; a power conversion circuit located on the power supply line and capable of converting an input voltage and outputting the converted voltage; a voltage detection unit that detects a voltage value output from the power conversion circuit; a current detection unit that detects a current value between the power conversion circuit and the output terminal; a control unit capable of controlling switching between an on state and an off state of the switch; Equipped with The control unit switches the switch to an OFF state when the magnitude of the voltage value detected by the voltage detection unit is equal to or less than a predetermined voltage threshold and the magnitude of the current value detected by the current detection unit is equal to or greater than a predetermined current threshold. power supply.

2. The control unit sets the current threshold to be larger in a charging state in which power is supplied from the output terminal to the battery than in a discharging state in which power is supplied from the battery to the output terminal. The power supply device of claim 1 .

3. the voltage threshold is a first voltage threshold, the current threshold is a first current threshold, a second voltage threshold value that is greater than the first voltage threshold value; When a threshold value smaller than the first current threshold value is set as a second current threshold value, The control unit switches the switch to an off state when one or more of a state in which the magnitude of the voltage value detected by the voltage detection unit is equal to or less than the second voltage threshold and a state in which the magnitude of the current value detected by the current detection unit is equal to or greater than the second current threshold continues for a predetermined period of time. The power supply device of claim 1 .

4. the voltage threshold is a first voltage threshold, the current threshold is a first current threshold, a second voltage threshold value that is greater than the first voltage threshold value; When a threshold value smaller than the first current threshold value is set as a second current threshold value, The control unit switches the switch to an off state when both a state in which the magnitude of the voltage value detected by the voltage detection unit is equal to or less than the second voltage threshold and a state in which the magnitude of the current value detected by the current detection unit is equal to or greater than the second current threshold continue for a predetermined period of time. The power supply device of claim 1 .

5. a pair of output terminals; a power supply line connected to the output terminal; a battery capable of outputting power from the output terminal via the power supply line; a switch located on the power supply line; a power conversion circuit located on the power supply line and capable of converting an input voltage and outputting the converted voltage; a voltage detection unit that detects a voltage value output from the power conversion circuit; a current detection unit that detects a current value between the power conversion circuit and the output terminal; a control unit capable of controlling switching between an on state and an off state of the switch; The present invention is applied to a power supply device comprising: The control unit switches the switch to an off state when the magnitude of the voltage value detected by the voltage detection unit is equal to or less than a predetermined voltage threshold value and the magnitude of the current value detected by the current detection unit is equal to or greater than a predetermined current threshold value. Program for power supply.

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