Power supply control device, state detection method, and computer program

Abstract

Provided are a power supply control device, a state detection method, and a computer program capable of suppressing, for example, an increase in the scale of a circuit for monitoring an output voltage from a supply device to a load.　The power supply control device according to the present embodiment controls supply operation by a supply device that supplies power from a power supply to a load connected to each of a plurality of output terminals. The power supply control device comprises: a plurality of first resistors that are electrically connected to the plurality of output terminals, respectively, and have respective different resistance values; a second resistor that is commonly connected to the plurality of first resistors; a first voltage detection unit that detects the voltage between the first resistors and the second resistor; and a state detection unit that detects the state of power supply from the output terminals to the loads on the basis of the voltage values detected by the first voltage detection unit.

Description

Power supply control device, state detection method, and computer program

[0001] The present disclosure relates to a power supply control device, a state detection method, and a computer program for controlling power supply to a load.

[0002] Patent Document 1 proposes a power semiconductor module in which a plurality of circuit bodies, each of which is a set of a forward power metal oxide semiconductor field effect transistor (MOSFET) and a reverse power MOS that are directly connected, are connected in parallel, and which function as a semiconductor fuse that protects the circuit from a large current supplied from a power supply.

[0003] Japanese Patent Application Laid-Open No. 2019-135819

[0004] A semiconductor fuse is provided in a power supply path from a power source such as a vehicle battery to a load such as a lamp or actuator to protect the load, and the semiconductor fuse switches the power supply from the power source to the load on and off. Conventionally, a microcomputer (microcontroller) has monitored the output voltage from the semiconductor fuse to the load to detect a failure or abnormality in the semiconductor fuse. In recent years, the number of loads installed in vehicles has increased, resulting in an increase in the size of the circuitry for the microcomputer to monitor the output voltage from the semiconductor fuse and an increase in the number of microcontroller ports required for monitoring.

[0005] The present disclosure has been made in consideration of the above circumstances, and its purpose is to provide a power supply control device, a status detection method, and a computer program that can suppress an increase in the size of a circuit for monitoring the output voltage from a supply device such as a semiconductor fuse to a load.

[0006] The power supply control device of this aspect is a power supply control device that controls the supply operation of a supply device that supplies power from a power source to loads connected to a plurality of output terminals, and includes a plurality of first resistors that are electrically connected to the plurality of output terminals, each having a different resistance value, a second resistor that is connected in common to the plurality of first resistors, a first voltage detection unit that detects the voltage between the first resistor and the second resistor, and a state detection unit that detects the state of power supply from the output terminal to the load based on the voltage value detected by the first voltage detection unit.

[0007] The present application can be realized not only as a device having such characteristic processing units, but also as a method having such characteristic processing steps, or as a computer program for causing a computer to execute such steps, or as a semiconductor integrated circuit that realizes part or all of these devices, or as other devices or systems that include these devices.

[0008] Based on the above, it is possible to suppress an increase in the size of a circuit for monitoring an output voltage from a supply device to a load.

[0009] FIG. 1 is a schematic diagram showing an example of the configuration of a power supply system according to the present embodiment. FIG. 2 is a schematic diagram showing the configuration of a power supply control device according to the present embodiment. FIG. 3 is a block diagram showing an example of the configuration of a microcomputer of the power supply control device according to the present embodiment. FIG. 4 is a schematic diagram for explaining the interruption of an overcurrent by the power supply control device according to the present embodiment. FIG. 5 is a schematic diagram showing an example of expected value information. FIG. 6 is a flowchart showing an example of the procedure of a state detection process performed by the microcomputer of the power supply control device according to the present embodiment. FIG. 7 is a schematic diagram showing the configuration of a power supply control device according to embodiment 2. FIG. 8 is a graph showing an example of the correspondence relationship between the forward voltage of a diode and current and temperature. FIG. 9 is a schematic diagram showing the configuration of a power supply control device according to embodiment 5.

[0010] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described. At least some of the embodiments described below may be combined in any combination.

[0011] (1) The power supply control device according to this aspect is a power supply control device that controls the supply operation of a supply device that supplies power from a power source to loads connected to a plurality of output terminals, and includes a plurality of first resistors that are electrically connected to the plurality of output terminals, each having a different resistance value, a second resistor that is commonly connected to the plurality of first resistors, a first voltage detection unit that detects the voltage between the first resistor and the second resistor, and a state detection unit that detects the state of power supply from the output terminal to the load based on the voltage value detected by the first voltage detection unit.

[0012] In this aspect, a power supply control device controls the operation of a supply device, such as a semiconductor fuse, that supplies power from a power source to a load. The power supply control device detects a voltage between first resistors connected to multiple output terminals of the supply device and a second resistor connected in common to the multiple first resistors. The multiple first resistors each have a different resistance value. Based on the detected voltage, the power supply control device detects the state of power supply from the output terminal of the supply device to the load. Because the multiple first resistors each have a different resistance value, the voltage detected by the power supply control device is determined depending on which load is being supplied with power. If the detected voltage differs from an expected voltage value, the power supply control device can detect that some abnormality or failure has occurred in the power supply from the supply device to the load. This allows the power supply control device to detect the state of power supply from multiple output terminals to the load by detecting a single voltage value, thereby suppressing an increase in the circuit size of the power supply control device.

[0013] (2) It is preferable that the power supply device is provided with a memory unit that stores an expected value of the voltage value detected by the first voltage detection unit or a range of the voltage value, in correspondence with a combination of one or more output terminals among the plurality of output terminals that are supplying power to a corresponding load, and that the state detection unit detects the state based on a comparison between the expected value or the range stored in the memory unit and the voltage value detected by the first voltage detection unit.

[0014] In this aspect, the power supply control device stores in a memory an expected value of a voltage value to be detected or a range for this voltage value, corresponding to a combination of one or more output terminals of the supply device that are supplying power to a load. The power supply control device detects the state of the power supply by comparing the detected voltage value with the stored expected value or range. For example, by setting in advance an appropriate expected value or range that takes into account the temperature characteristics or current characteristics of circuit elements, the power supply control device can easily and accurately detect the state of the power supply.

[0015] (3) It is preferable that a second voltage detection unit is provided to detect the voltage value of the power supply, the memory unit stores the expected value or the range in association with the voltage value of the power supply, and the state detection unit detects the state based on a comparison between the expected value or the range stored in the memory unit in association with the voltage value detected by the second voltage detection unit and the voltage value detected by the first voltage detection unit.

[0016] In this aspect, the power supply control device detects the voltage value of the power supply. The power supply control device stores an expected value or range in a memory unit in association with the power supply voltage value, and detects the state using the expected value or range corresponding to the detected power supply voltage value. This allows the power supply control device to detect the state using an expected value or range appropriate for changes in the power supply voltage value, etc., and to accurately detect the state of the power supply.

[0017] (4) It is preferable that the power supply device is provided with a temperature detection unit that detects temperature, the memory unit stores the expected value or the range in association with the voltage value of the power supply and the temperature, and the state detection unit detects the state based on a comparison between the voltage value detected by the first voltage detection unit and the expected value or the range stored in the memory unit in association with the voltage value detected by the second voltage detection unit and the temperature detected by the temperature detection unit.

[0018] In this aspect, the power supply control device detects the voltage value and temperature of the power supply. The power supply control device stores expected values ​​or ranges associated with the power supply voltage value and temperature in a memory unit, and detects the state using the expected value or range corresponding to the detected power supply voltage value and temperature. This allows the power supply control device to detect the state using an expected value or range appropriate for changes in the power supply voltage value or temperature, etc., and to accurately detect the state of the power supply.

[0019] (5) It is preferable that a diode is provided between the output terminal and the first resistor, and the expected value or the range is determined according to the characteristics of the diode regarding temperature, voltage, or current.

[0020] In this aspect, a diode is provided between the supply device and each first resistor, for example, to prevent reverse current flow. The expected value or range stored in the memory unit by the power supply control device is determined based on the temperature, voltage, or current characteristics of the diode. Because the forward voltage of a diode changes depending on the temperature, voltage, or current, determining the expected value or range in advance while taking this into consideration allows the power supply control device to accurately detect the state.

[0021] (6) Preferably, the state detection unit detects the state when the supply of power to the load is switched from on to off or from off to on.

[0022] In this aspect, when the supply of power to each load by the supply device is switched from on (supply state) to off (non-supply state) or from off to on, the power supply control device performs status detection, which reduces the processing load on the power supply control device compared to when status detection is performed constantly or intermittently.

[0023] (7) It is preferable to include the supply device.

[0024] In this aspect, the power supply control device includes a supply device that supplies power from a power source to a load. Compared to a case where the power supply control device and the supply device are provided as separate devices, a configuration in which the power supply control device includes the supply device can achieve a smaller device size, lower costs, etc.

[0025] (8) In the state detection method according to this aspect, a power supply control device that controls the supply operation of a supply device that supplies power from a power source to loads connected to a plurality of output terminals detects a voltage between a plurality of first resistors that are electrically connected to the plurality of output terminals and have different resistance values, and a second resistor that is commonly connected to the plurality of first resistors, and detects the state of power supply from the output terminals to the loads based on the detected voltage value.

[0026] In this aspect, similar to the aspect (1), it is possible to suppress an increase in the circuit scale of the power supply control device.

[0027] (9) The computer program according to this aspect causes a computer that controls the supply operation of a supply device that supplies power from a power source to loads connected to a plurality of output terminals to detect a voltage between a plurality of first resistors that are electrically connected to the plurality of output terminals and have different resistance values, and a second resistor that is commonly connected to the plurality of first resistors, and detects the state of power supply from the output terminals to the loads based on the detected voltage value.

[0028] In this aspect, similar to the aspect (1), it is possible to suppress an increase in the circuit scale of the power supply control device.

[0029] [Details of the embodiment of the present disclosure] Specific examples of information processing systems according to the embodiment of the present disclosure will be described below with reference to the drawings. The present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0030] [Embodiment 1] <System Configuration> FIG. 1 is a schematic diagram showing an example configuration of a power supply system according to this embodiment. The power supply system according to this embodiment is a system configured such that a power supply control device 3 disposed in an appropriate location on the vehicle 1 controls the supply of power to multiple loads 61-64 mounted on the vehicle 1 from a power source such as a battery 2 or an alternator (not shown) mounted on the vehicle 1. The loads 61-64 may be various electrical components of the vehicle 1, such as headlights, room lamps, wipers, locking mechanism actuators, or liquid crystal displays. Although FIG. 1 illustrates four loads 61-64, the number of loads controlled by the power supply control device 3 may be three or less or five or more. The battery 2 and the power supply control device 3 are connected via power lines arranged within the vehicle 1, and the power supply control device 3 and each of the loads 61-64 are connected via individual power lines.

[0031] FIG. 2 is a schematic diagram showing the configuration of a power supply control device 3 according to this embodiment. The power supply control device 3 according to this embodiment is configured with an IPD (Intelligent Power Device) 4, a microcomputer (microcontroller) 5, and the like. The IPD 4 is an IC (Integrated Circuit) with a built-in protection circuit and the like in a semiconductor switch, and is a circuit element used as a semiconductor fuse. The IPD 4 is provided in a power supply path from a power source (indicated by "+B" in FIG. 2) to loads 61-64, and switches the power supply from the power source to each of the loads 61-64 on (supply) or off (non-supply) in accordance with the control of the microcomputer 5. The IPD 4 also has the function of protecting each of the loads 61-64 by interrupting the power supply path from the power source to each of the loads 61-64 in the event of an overcurrent or other problem from the power source to each of the loads 61-64.

[0032] In the present embodiment, the IPD 4 has one input terminal 40 connected to a power source and four output terminals 41 to 44 connected individually to four loads 61 to 64. The input terminal 40 of the IPD 4 is electrically connected to a power source such as the battery 2, for example, via a wiring pattern provided on a circuit board included in the power supply control device 3 and a power line arranged within the vehicle 1. Similarly, the output terminals 41 to 44 of the IPD 4 are individually electrically connected to the loads 61 to 64, for example, via a wiring pattern provided on a circuit board included in the power supply control device 3 and a power line arranged within the vehicle 1. The IPD 4 can supply power input from the input terminal 40 from the multiple output terminals 41 to 44 by individually switching on / off the power.

[0033] The microcomputer 5 exchanges information via communication with, for example, other on-board devices provided in the vehicle 1, and determines whether or not power needs to be supplied to each of the loads 61 to 64 based on the information obtained. The microcomputer 5 outputs a control signal to the IPD 4, and this control signal can individually control whether or not power is supplied from each of the output terminals 41 to 44 of the IPD 4. The microcomputer 5 also has an input terminal 50, and can detect the voltage value of a signal input from the input terminal 50 and perform various processes according to the detected voltage value.

[0034] The power supply control device 3 according to this embodiment includes four diodes D1 to D4 and six resistors R11 to R14, R2, and R3 that constitute a circuit for detecting the status of power supply from the IPD 4 to each of the loads 61 to 64. Each power supply path from the output terminals 41 to 44 of the IPD 4 to the loads 61 to 64 branches midway and is connected to the anodes of the diodes D1 to D4. The cathodes of the diodes D1 to D4 are connected to one end of the resistors R11 to R14. The other ends of the four resistors R11 to R14 are bundled together and connected to one end of a single resistor R2, the other end of which is connected to ground potential. The other ends of the four resistors R11 to R14 and one end of the resistor R2 are connected to one end of a single resistor R3, the other end of which is connected to an input terminal 50 of the microcomputer 5.

[0035] In this embodiment, for example, an expression such as "connected" between A and B does not only mean that A and B are directly connected, but also includes an electrical connection via, for example, a wiring pattern or a signal line on a circuit board. Furthermore, some kind of circuit or circuit element may be provided in the electrical path connecting A and B for, for example, noise removal, signal amplification, signal attenuation, or signal delay. In other words, a configuration in which A and B are electrically connected via some kind of circuit or circuit element is possible.

[0036] The voltage value between the four resistors R11-R14 and the single resistor R2 is input to the input terminal 50 of the microcomputer 5 via resistor R3. In the power supply system according to this embodiment, the four resistors R11-R14 of the power supply control device 3 are each set to a different resistance value. It is preferable that the four diodes D1-D4 have the same characteristics. A different voltage value is input to the input terminal 50 of the microcomputer 5 depending on which of the loads 61-64 is being powered. The microcomputer 5 pre-stores information about the expected value of the voltage value input from the input terminal 50 when the IPD 4 supplies power to the loads 61-64 from each of the output terminals 41-44. The microcomputer 5 can detect whether or not there is an abnormality in the power supply from the IPD 4 to the loads 61-64 based on whether the voltage value input from the input terminal 50 is within a normal range, such as ±10% of this expected value. The IPD 4 may simultaneously supply power to any number of loads 61-64, and the microcontroller 5 may store information about expected values ​​corresponding to a combination of one or more output terminals 41-44 to which the IPD 4 supplies power. Note that in the above example, the normal range is ±10% of the expected value, but this value is merely an example and is not limiting. For example, a designer may determine an appropriate percentage of the expected value, such as ±1% or ±20%. Furthermore, the range above and below the expected value may be unequal, such as -10% to +5% of the expected value. Furthermore, instead of defining the normal range as a percentage of the expected value, the normal range may be defined as a fixed value, such as ±0.1 V, relative to the expected value.

[0037] In this embodiment, the microcomputer 5 of the power supply control device 3 does not periodically acquire the voltage value input from the input terminal 50 to detect the presence or absence of an abnormality, but rather acquires the voltage value, for example, when the state of the power supply from the IPD 4 to each of the loads 61 to 64 is switched, and detects the presence or absence of an abnormality. In this embodiment, the IPD 4 switches the power supply to each of the loads 61 to 64 on and off in response to a control signal provided by the microcomputer 5. This allows the microcomputer 5 to grasp the timing at which the IPD 4 switches the power supply in response to the control signal. The microcomputer 5 acquires the voltage value input from the input terminal 50 to detect the presence or absence of an abnormality, for example, when the IPD 4 switches the power supply on and off or when a predetermined delay time has elapsed since the switching. Note that the microcomputer 5 may perform an abnormality detection multiple times rather than just once for each on / off switching of the power supply by the IPD 4.

[0038] By detecting an abnormality based on the voltage value, the microcomputer 5 can detect the occurrence of an abnormality, such as, for example, power not being supplied to the loads 61 to 64 to which power should be supplied, power being supplied to the loads 61 to 64 to which power should not be supplied, or an unexpected amount of power being supplied to the loads 61 to 64. When the microcomputer 5 detects an abnormality in the power supply to the loads 61 to 64 by the IPD 4, the microcomputer 5 can perform processing such as, for example, outputting a control signal to stop all power supply by the IPD 4, or notifying other in-vehicle devices in the vehicle 1 of the abnormality in the IPD 4 by communication via the in-vehicle network. Furthermore, for example, the microcomputer 5 may notify the user of the occurrence of the abnormality using a display device or a lamp provided near the driver's seat of the vehicle 1.

[0039] 3 is a block diagram showing an example configuration of the microcomputer 5 of the power supply control device 3 according to this embodiment. The microcomputer 5 according to this embodiment is configured with a processing unit 51, a storage unit 52, an AD (Analog to Digital) conversion unit 53, a signal output unit 54, and the like. The processing unit 51 is configured using an arithmetic processing device such as a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The processing unit 51 can perform various processes by reading and executing a program 52a stored in the storage unit 52. In this embodiment, the processing unit 51 performs processes such as controlling the on / off switching of power supply to each of the loads 61 to 64 by the IPD 4 and detecting the status of the power supply.

[0040] The storage unit 52 is configured using a non-volatile memory element such as a flash memory or an EEPROM (Electrically Erasable Programmable Read Only Memory). The storage unit 52 stores various programs executed by the processing unit 51 and various data required for the processing of the processing unit 51. In this embodiment, the storage unit 52 stores a program 52a executed by the processing unit 51 and expected value information 52b used to detect the state of the power supply.

[0041] The program (program product) 52a may be written to the storage unit 52 during the manufacturing stage of the power supply control device 3, or may be distributed by a remote server device or the like and acquired by the power supply control device 3 via communication and stored in the storage unit 52 of the microcomputer 5, or the power supply control device 3 may read a program recorded on a recording medium 99 such as a memory card or optical disk and store it in the storage unit 52 of the microcomputer 5, or a writing device may read something recorded on the recording medium 99 and write it into the storage unit 52 of the microcomputer 5 of the power supply control device 3. The program 52a may be provided in the form of distribution via a network or in the form of being recorded on the recording medium 99.

[0042] The expected value information 52b is information relating to the expected value of the voltage value detected by the microcomputer 5 in response to the power supply to each of the loads 61 to 64 by the IPD 4. The expected value information 52b is determined in advance, for example, by a designer of the vehicle 1, the power supply system, or the power supply control device 3 according to this embodiment, and is stored in the storage unit 52 of the microcomputer 5 of the power supply control device 3. The expected value information 52b is information that associates, for example, from which of the output terminals 41 to 44 the IPD 4 supplies power to the loads 61 to 64 with the expected value of the voltage value input from the input terminal 50 of the microcomputer 5.

[0043] The AD conversion unit 53 is connected to the input terminal 50, samples and acquires the voltage value of an analog signal input from the input terminal 50, converts it into a digital voltage value, and provides the converted digital data to the processing unit 51. In this embodiment, the AD conversion unit 53 converts the voltage value between the resistors R11 to R14 and the resistor R2 input from the input terminal 50 into digital data. For example, if the power supply voltage of the microcomputer 5 is 5 V and the digital data output by the AD conversion unit 53 is 10 bits long, the resolution of the voltage value converted by the AD conversion unit 53 is approximately 0.00488 V. Note that these numerical values ​​are merely examples and are not limited to these.

[0044] The signal output unit 54 generates and outputs one or more control signals for controlling the operation of the IPD 4 in accordance with the processing of the processing unit 51. In the present embodiment, the signal output unit 54 outputs at least a control signal for individually switching on / off the power supply from the IPD 4 to each of the loads 61 to 64. Transmission and reception of control signals between the signal output unit 54 and the IPD 4 may be performed using either parallel communication or serial communication. For example, if the IPD 4 has four output terminals 41 to 44, the signal output unit 54 can be configured to output four binary control signals to the IPD 4, each of which corresponds to a high level or low level and indicates whether the power supply is on or off for each of the output terminals 41 to 44.

[0045] <Overcurrent Protection Function> Figure 4 is a schematic diagram for explaining the interruption of an overcurrent by the power supply control device 3 according to this embodiment. Figure 4 shows a graph of power supplied from a power source to a load, with the vertical axis representing the current value [A] flowing to the load and the horizontal axis representing the time [seconds] that this current has flowed. The characteristic shown by the thick solid line in this graph is a smoke generation characteristic indicating that a failure such as smoke generation will occur in the load due to an overcurrent, and for example, it shows that smoke will be generated in the load when a current of 10,000 A flows for 0.001 seconds.

[0046] In contrast, the characteristic indicated by the dashed dotted line in the graph of Figure 4 is the overcurrent cutoff characteristic of the IPD 4. The IPD 4 cuts off (turns off) the power supply to the load when a current of approximately 100 A flows through the load, regardless of the duration for which the current has flowed. This cutoff function of the IPD 4 is performed regardless of control from the microcomputer 5, and is a function realized by an internal circuit of the IPD 4 (not shown). Because this cutoff function by the IPD 4 is an existing function, detailed explanation of the method for realizing it will be omitted.

[0047] However, the smoke generation characteristics shown in the graph of FIG. 4 indicate that even if the current value is less than 100 A, smoke generation can occur if the current flows for more than approximately 10 seconds. In this case, it is difficult to prevent smoke generation using only the shutdown function of the IPD 4. In the power supply control device 3 according to this embodiment, the microcomputer 5 detects an abnormality based on the voltage value input from the input terminal 50 and, if an abnormality is detected, controls the IPD 4 to switch off the power supply. This protects against overcurrents that cannot be cut off using the shutdown function of the IPD 4. The thin solid line in the graph of FIG. 4 indicates the overcurrent shutdown characteristics of the microcomputer 5. The microcomputer 5 can also shut off overcurrents with low current values ​​and long durations exceeding approximately 10 seconds, which the shutdown function of the IPD 4 cannot handle. The power supply control device 3 according to this embodiment uses the shutdown function of the IPD 4 to shut off high-current, short-duration overcurrents, and the microcomputer 5 to shut off low-current, long-duration overcurrents, thereby preventing load failures due to overcurrents.

[0048] <Status Detection Process> The power supply control device 3 according to this embodiment has a status detection circuit configured such that the output terminals 41-44 of the IPD 4 are connected to the anodes of diodes D1-D4, respectively, the cathodes of the diodes D1-D4 are connected to one end of resistors R11-R14, respectively, the other ends of the resistors R11-R14 are connected to one end of a common resistor R2, and the other end of the resistor R2 is connected to ground. The microcomputer 5 acquires the voltage value at the junction of the four resistors R11-R14 and resistor R2 to detect an abnormality in the power supply to the loads by the IPD 4. In this embodiment, the four resistors R11-R14 each have a different resistance value, and the microcomputer 5 can distinguish which output terminals 41-44 and which loads 61-64 are experiencing an abnormality in the power supply based on the difference in the detected voltage values.

[0049] The microcomputer 5 of the power supply control device 3 according to this embodiment acquires a voltage value input from the input terminal 50 and compares it with pre-stored expected value information 52b to detect the presence or absence of an abnormality in the power supply from the IPD 4 to the loads 61 to 64. FIG. 5 is a schematic diagram showing an example of the expected value information 52b. The expected value information 52b stored in the storage unit 52 by the microcomputer 5 of the power supply control device 3 according to this embodiment is information that associates, for example, information indicating whether the four output terminals 41 to 44 of the IPD 4 are in a state in which power is being supplied to the loads 61 to 64 (ON) or a state in which power is not being supplied (OFF) with an expected value of the voltage value input from the input terminal 50 of the microcomputer 5.

[0050] 5, the table shown as expected value information 52b distinguishes between the four output terminals 41 to 44 of the IPD 4 by labeling them as the first to fourth outputs. That is, output terminal 41 of the IPD 4 corresponds to the first output, output terminal 42 corresponds to the second output, output terminal 43 corresponds to the third output, and output terminal 44 corresponds to the fourth output. In the table of FIG. 5, the output terminals 41 to 44 that are supplying power to the loads 61 to 64 are marked "on," and those that are not supplying power are marked blank (no marking).

[0051] 5 are values ​​when the resistance value of resistor R11 in the circuit configuration of Fig. 2 is 10 kΩ, the resistance value of resistor R12 is 13 kΩ, the resistance value of resistor R13 is 20 kΩ, the resistance value of resistor R14 is 27 kΩ, and the resistance value of resistor R2 is 1 kΩ, the power supply voltage +B (output voltage of IPD4) is 12 V, and the forward voltage Vf of diodes D1 to D4 is 0.7 V. The resistance value of resistor R3 is determined appropriately based on the characteristics of input terminal 50 of microcomputer 5, and in this embodiment, it is assumed that no voltage drop occurs across resistor R3.

[0052] The expected voltage values ​​of expected value information 52b are calculated by dividing the voltage value obtained by subtracting forward voltage Vf from the power supply voltage, based on the ratio between the combined resistance value of one or more resistors R11 to R14 corresponding to the on-state output and the resistance value of resistor R2. For example, a designer of the power supply system according to this embodiment calculates these expected voltage values ​​in advance to create expected value information 52b, and stores expected value information 52b in storage unit 52 of microcomputer 5, for example, during the manufacturing process or inspection process of power supply control device 3 or vehicle 1.

[0053] The power supply control device 3 operates, for example, when the ignition switch of the vehicle 1 is in the on state, and controls the power supply from a power source such as the battery 2 to the loads 61 to 64. The microcomputer 5 of the power supply control device 3 determines to which of the loads 61 to 64 power should be supplied, for example, based on information from other in-vehicle devices or a switch operation by the user, and provides a control signal to the IPD 4. When the microcomputer 5 switches the on / off state of the power supply to each of the loads 61 to 64, it samples and acquires the voltage value input from the input terminal 50, and detects the presence or absence of an abnormality based on the acquired voltage value.

[0054] At this time, the microcomputer 5 determines from which of the output terminals 41 to 44 power is being supplied to the loads 61 to 64 based on the control signal sent to the IPD 4, and obtains the expected voltage value corresponding to the combination of the output terminals 41 to 44 supplying power from the expected value information 52b stored in the storage unit 52. The microcomputer 5 determines the normal range to be, for example, a voltage range of ±10% of the obtained expected voltage value. Note that the normal range of ±10% of the expected voltage value is one example and is not limited to this. The normal range for the expected voltage value is set in advance by a user, such as a designer of the power supply system according to this embodiment. The normal range may be determined not as a percentage of the expected voltage value, but as a fixed value such as the expected voltage value ±0.1 V.

[0055] In this embodiment, the microcomputer 5 stores the expected voltage value as information serving as a reference for detecting an abnormality, but this is not limiting. The microcomputer 5 may store upper and lower threshold values ​​that define a normal range in advance instead of or together with the expected voltage value.

[0056] The microcomputer 5 detects an abnormality in the power supply by determining whether the voltage value input from the input terminal 50 is within a normal range determined based on the expected voltage value. If the voltage value is outside the normal range, the microcomputer 5 stops the power supply from all output terminals 41-44 to loads 61-64 by the IPD 4, for example, using a control signal, and notifies other on-board devices installed in the vehicle 1 or a user such as the driver of the vehicle 1 that an abnormality has occurred. If the voltage value is within the normal range, the microcomputer 5 continues the power supply by the IPD 4.

[0057] 6 is a flowchart showing an example of the procedure of a state detection process performed by the microcomputer 5 of the power supply control device 3 according to this embodiment. The processing unit 51 of the microcomputer 5 according to this embodiment determines whether or not the state of power supply from the output terminals 41 to 44 of the IPD 4 to the loads 61 to 64 has changed, based on the state of the control signal output to the IPD 4 (step S1). If there is no change in the power supply state (S1: NO), the processing unit 51 waits until the power supply state changes.

[0058] If the power supply state has changed (S1: YES), the voltage detection unit 51a of the processing unit 51 detects the voltage value between the resistors R11-R14 and the resistor R2 by acquiring the voltage value input from the input terminal 50 via the AD conversion unit 53 (step S2). The state detection unit 51b of the processing unit 51 acquires the voltage expected value from the expected value information 52b stored in the storage unit 52 based on the combination of the output terminals 41-44 of the IPD 4 that are currently supplying power to the loads 61-64 (step S3).

[0059] The state detection unit 51b determines whether the voltage value detected in step S2 is within a normal range based on the expected voltage value acquired in step S3 (step S4). If the voltage value is within the normal range (S4: YES), the state detection unit 51b returns the process to step S1. If the voltage value is not within the normal range (S4: NO), the processing unit 51 outputs a control signal to cut off the power supply from the output terminals 41 to 44 of the IPD 4 to the loads 61 to 64 (step S5). The processing unit 51 also notifies other in-vehicle devices of the vehicle 1 of the abnormality, for example, by communication via the in-vehicle network, or displays a message on a display provided near the driver's seat of the vehicle 1 to notify a user, such as the driver, of the abnormality (step S6), and then ends the process.

[0060] Summary In the power supply system according to the present embodiment, a power supply control device 3 controls the operation of an IPD (supply device) 4, such as a semiconductor fuse, which supplies power from a power source such as a battery 2 to multiple loads 61-64. The power supply control device 3 detects the voltage between first resistors R11-R14 connected to multiple output terminals 41-44 of the IPD 4 and a second resistor R2 connected in common to the multiple first resistors R11-R14. The multiple first resistors R11-R14 each have a different resistance value. Based on the detected voltage, the power supply control device 3 detects the status of the power supply from the output terminals 41-44 of the IPD 4 to the loads 61-64 (e.g., whether an abnormality exists). Because the multiple first resistors R11-R14 each have a different resistance value, the voltage detected by the power supply control device 3 is determined depending on which of the loads 61-64 is being supplied with power. If the detected voltage value is different from the expected voltage value, the power supply control device 3 can detect that some abnormality or failure has occurred in the power supply from the IPD 4 to the loads 61 to 64. This allows the power supply control device 3 to detect the state of the power supply from the multiple output terminals 41 to 44 to the loads 61 to 64 by detecting a single voltage value, thereby preventing an increase in the circuit size of the power supply control device 3.

[0061] Furthermore, in the power supply system according to this embodiment, the power supply control device 3 stores in the storage unit 52 an expected value for the voltage value to be detected or a range for this voltage value (such as upper and lower thresholds that define this range) in association with a combination of one or more of the output terminals 41-44 of the IPD 4 that are supplying power to the loads 61-64. The power supply control device 3 detects the state of the power supply by comparing the detected voltage value with the stored expected value or range. For example, by setting in advance an appropriate expected value or range that takes into account the temperature characteristics or current characteristics of circuit elements, the power supply control device 3 can easily and accurately detect the state of the power supply.

[0062] Furthermore, in the power supply system according to this embodiment, when the supply of power to each of the loads 61 to 64 by the IPD 4 is switched from on (supply state) to off (non-supply state) or from off to on, the power supply control device 3 detects the state. This reduces the processing load on the power supply control device 3 compared to when state detection is performed constantly or intermittently.

[0063] Furthermore, in the power supply system according to the present embodiment, the power supply control device 3 includes an IPD 4 that supplies power from the power source to the loads 61 to 64. Compared to a case in which the power supply control device 3 and the IPD 4 are provided as separate devices, a configuration in which the power supply control device 3 includes the IPD 4 can achieve a smaller device size, lower costs, and the like.

[0064] In this embodiment, the power supply control device 3 is configured to supply power to four loads 61 to 64, but this is not limited thereto, and the power supply control device 3 may be configured to supply power to three or fewer loads or five or more loads. Also, in this embodiment, the IPD 4 is configured to have four output terminals 41 to 44, but this is not limited thereto, and the IPD 4 may be configured to have three or fewer output terminals or five or more output terminals. The power supply control device 3 may be provided with, for example, two IPDs 4 each having two output terminals to supply power to four loads 61 to 64, or may be provided with, for example, four IPDs 4 each having one output terminal to supply power to four loads 61 to 64.

[0065] Furthermore, in the information processing system according to the present embodiment, the power supply control device 3 stores the voltage expectation value for state detection as expected value information 52b in the storage unit 52, but the present invention is not limited to this. For example, the power supply control device 3 may store an arithmetic expression for calculating the voltage expectation value, and calculate the voltage expectation value using the stored arithmetic expression based on the resistance values ​​of resistors R11 to R14 and resistor R2 and which of output terminals 41 to 44 is supplying power to the loads 61 to 64.

[0066] [Embodiment 2] FIG. 7 is a schematic diagram showing the configuration of a power supply control device 3 according to embodiment 2. The power supply control device 3 according to embodiment 2 has a configuration in which a power supply voltage detection unit 71 and a temperature detection unit 72 are added to the power supply control device 3 according to embodiment 1 shown in FIG. 2. The power supply voltage detection unit 71 detects the value of the power supply voltage input to the IPD 4 of the power supply control device 3 from a power source such as the battery 2, and notifies the microcomputer 5 of the detected power supply voltage value. The temperature detection unit 72 detects the ambient temperature using, for example, a thermistor, and notifies the microcomputer 5 of the detected temperature. In embodiment 2, the temperature detection unit 72 is preferably arranged near the diodes D1 to D4 included in the circuit shown in FIG. 7 and detects the temperatures of the diodes D1 to D4.

[0067] 8 is a graph showing an example of the correspondence relationship between the forward voltage Vf of the diodes D1 to D4 and the current and temperature. The graph shown has the forward voltage Vf of the diodes D1 to D4 on the horizontal axis and the current value If flowing through the diodes D1 to D4 on the vertical axis. The graph also shows the correspondence relationship between the forward voltage Vf and the current value If at seven temperatures: 175°C, 150°C, 125°C, 100°C, 85°C, 25°C, and -40°C. This graph shows that the forward voltage Vf of the diodes D1 to D4 depends on the temperature and the current value If.

[0068] In the power supply system according to the second embodiment, the power supply voltage, which affects the amount of current flowing through the diodes D1 to D4, and the temperatures of the diodes D1 to D4 are detected, and the power supply control device 3 detects the presence or absence of an abnormality in the power supply from the output terminals 41 to 44 of the IPD 4 to the loads 61 to 64, taking into account the power supply voltage and temperature. The microcomputer 5 of the power supply control device 3 according to the second embodiment stores, in the storage unit 52, multiple pieces of expected value information 52b corresponding to multiple combinations of power supply voltages and multiple temperatures. That is, if there are M combinations of power supply voltages and N combinations of temperatures, the microcomputer 5 stores M×N combinations of expected value information 52b in the storage unit 52 (where M and N are positive integers).

[0069] When detecting an abnormality in the power supply, the microcomputer 5 acquires the power supply voltage detected by the power supply voltage detection unit 71 and the temperature detected by the temperature detection unit 72, and reads expected value information 52b corresponding to the acquired combination of power supply voltage and temperature from the storage unit 52. The microcomputer 5 acquires, from the expected value information 52b corresponding to the combination of power supply voltage and temperature, the expected voltage value corresponding to the combination of output terminals 41 to 44 that are supplying power to loads 61 to 64. The microcomputer 5 acquires a voltage value input from the input terminal 50 and compares it with the expected voltage value acquired from the expected value information 52b to detect an abnormality in the power supply.

[0070] In the power supply system according to the second embodiment having the above configuration, the power supply control device 3 detects the voltage value and temperature of the power supply. The power supply control device 3 stores expected values ​​or ranges associated with the power supply voltage value and temperature in the storage unit 52, and performs status detection using the expected values ​​or ranges corresponding to the detected power supply voltage value and temperature. This allows the power supply control device 3 to perform status detection using expected values ​​or ranges appropriate for changes in the power supply voltage value or temperature, etc., and to accurately detect the status of the power supply.

[0071] In the power supply system according to the second embodiment, diodes D1 to D4 are provided between the output terminals 41 to 44 of the IPD 4 and each of the first resistors R11 to R14, respectively, for example, to prevent reverse current flow. The expected values ​​or ranges that the power supply control device 3 stores in the memory unit 52 of the microcomputer 5 are determined according to the temperature, voltage, or current characteristics of the diodes D1 to D4. Because the forward voltages Vf of the diodes D1 to D4 change depending on the temperature, voltage, or current, determining the expected values ​​or ranges in advance while taking this into consideration allows the power supply control device 3 to detect the state with high accuracy.

[0072] In the second embodiment, the plurality of pieces of expected value information 52b are created in advance based on the power supply voltage characteristics and temperature characteristics of the diodes D1 to D4, but this is not limiting. The plurality of pieces of expected value information 52b may be created in advance based on, for example, the temperature characteristics of the resistors R11 to R14 and the resistor R2, or the power supply voltage characteristics and temperature characteristics of the IPD 4. The power supply control device 3 may be configured to include either a power supply voltage detection unit 71 or a temperature detection unit 72, and the plurality of pieces of expected value information 52b corresponding to either the power supply voltage characteristics or the temperature characteristics may be stored in the storage unit 52 of the microcomputer 5.

[0073] Furthermore, other configurations of the power supply system according to the second embodiment are the same as those of the power supply system according to the first embodiment, so the same reference numerals are used for the same parts and detailed description thereof will be omitted.

[0074] [Third Embodiment] The power supply control device 3 according to the third embodiment is configured such that the temperature detection unit 72 is not included in the power supply control device 3 according to the second embodiment shown in Fig. 7. In other words, the power supply control device 3 according to the third embodiment is configured such that a power supply voltage detection unit 71 is added to the power supply control device 3 according to the first embodiment shown in Fig. 2. The power supply voltage detection unit 71 detects the value of the power supply voltage input to the IPD 4 and notifies the microcomputer 5 of the value.

[0075] The microcomputer 5 of the power supply control device 3 according to the third embodiment stores a plurality of pieces of expected value information 52b corresponding to a plurality of power supply voltages in the storage unit 52. The microcomputer 5 acquires the power supply voltage detected by the power supply voltage detection unit 71 and reads out the expected value information 52b corresponding to the acquired power supply voltage from the storage unit 52. The microcomputer 5 acquires, from the expected value information 52b corresponding to the power supply voltage, an expected voltage value corresponding to the combination of the output terminals 41 to 44 that are supplying power to the loads 61 to 64. The microcomputer 5 acquires a voltage value input from the input terminal 50 and compares it with the expected voltage value acquired from the expected value information 52b to detect an abnormality in the power supply.

[0076] In the power supply system according to the third embodiment having the above configuration, the power supply control device 3 detects the voltage value of the power supply. The power supply control device 3 stores an expected value or range in association with the power supply voltage value in the storage unit 52, and performs status detection using the expected value or range corresponding to the detected power supply voltage value. This allows the power supply control device 3 to perform status detection using an expected value or range appropriate for changes in the power supply voltage value, etc., and to accurately detect the status of the power supply.

[0077] Furthermore, other configurations of the power supply system according to the third embodiment are the same as those of the power supply systems according to the first and second embodiments, so the same reference numerals are used for the same parts and detailed description thereof will be omitted.

[0078] [Fourth Embodiment] The power supply control device 3 according to the fourth embodiment is configured such that the power supply voltage detection unit 71 is not included in the power supply control device 3 according to the second embodiment shown in Fig. 7. In other words, the power supply control device 3 according to the fourth embodiment is configured such that a temperature detection unit 72 is added to the power supply control device 3 according to the first embodiment shown in Fig. 2. The temperature detection unit 72 detects the temperatures around the diodes D1 to D4 and notifies the microcomputer 5 of the detected temperatures.

[0079] The microcomputer 5 of the power supply control device 3 according to the fourth embodiment stores a plurality of pieces of expected value information 52b corresponding to a plurality of temperatures in the storage unit 52. The microcomputer 5 acquires the temperature detected by the temperature detection unit 72 and reads out the expected value information 52b corresponding to the acquired temperature from the storage unit 52. The microcomputer 5 acquires, from the expected value information 52b corresponding to the temperature, an expected voltage value corresponding to the combination of the output terminals 41 to 44 that are supplying power to the loads 61 to 64. The microcomputer 5 acquires a voltage value input from the input terminal 50 and compares it with the expected voltage value acquired from the expected value information 52b to detect an abnormality in the power supply.

[0080] In the power supply system according to the fourth embodiment having the above configuration, the power supply control device 3 detects the temperature. The power supply control device 3 stores an expected value or range associated with the temperature in the storage unit 52, and detects the state using the expected value or range corresponding to the detected temperature. This allows the power supply control device 3 to detect the state using an expected value or range appropriate for changes in the power supply voltage value or temperature, etc., and to accurately detect the state of the power supply.

[0081] Furthermore, other configurations of the power supply system according to embodiment 4 are the same as those of the power supply systems according to embodiments 1 to 3, so the same reference numerals are used for similar parts and detailed explanations are omitted.

[0082] 9 is a schematic diagram showing the configuration of a power supply control device 3 according to embodiment 5. The IPD 4 included in the power supply control device 3 according to embodiment 5 has a sense output terminal 545 that outputs a sense current having a current value corresponding to the currents output from the output terminals 41 to 44 to the loads 61 to 64. The IPD 4 outputs, from the sense output terminal 545, a sense current having a current value that is, for example, 1 / a times (a is a real number greater than or equal to 1) the total current value of the currents output from the output terminals 41 to 44.

[0083] The sense output terminal 545 of the IPD 4 is connected to the ground potential via a resistor R51, and is also connected to the input terminal of the microcomputer 5 via a resistor R52. The input terminal of the microcomputer 5 is connected to the ground potential via a capacitor C51. The microcomputer 5 samples the voltage value of the voltage input from this input terminal, thereby converting the analog voltage value into a digital voltage value and acquiring it.

[0084] The IPD 4 outputs, from a sense output terminal 545, a sense current corresponding to the output current from the output terminals 41 to 45 to the loads 61 to 64. The sense current output from the sense output terminal 545 flows to the ground potential via a resistor R51, and the voltage applied to the resistor R51 at this time is input to an input terminal of the microcomputer 5 via a resistor R52. The resistor R52 is a resistor that limits the sense current from flowing into the microcomputer 5. The capacitor C51 is used to smooth the voltage input to the microcomputer 5 or to reduce noise.

[0085] The microcomputer 5 is given a predetermined resistance value for the resistor R51, and can calculate the current value of the sense current output by the IPD 4 based on the voltage value input to the input terminal and this resistance value. The microcomputer 5 is also given a predetermined ratio (e.g., the value of a) between the output current and the sense current of the IPD 4, and can calculate the current value output by the IPD 4 from the output terminals 41 to 44 to the loads 61 to 64 based on the calculated current value of the sense current and this ratio, and can perform processing according to the output current value of the IPD 4. However, the microcomputer 5 does not necessarily need to calculate the current value of the sense current and the current value of the output current in order to perform the subsequent processing, and may perform the subsequent processing according to the voltage value input to the input terminal.

[0086] The microcomputer 5 of the power supply control device 3 according to the fifth embodiment stores, in the storage unit 52, a plurality of pieces of expected value information 52b corresponding to a plurality of output current values. The microcomputer 5 acquires a voltage value corresponding to the sense current output from the sense output terminal 545 by the IPD 4 and calculates the output current value of the IPD 4 based on the acquired voltage value. The microcomputer 5 reads, from the storage unit 52, the expected value information 52b corresponding to the calculated output current value. The microcomputer 5 acquires, from the expected value information 52b corresponding to the output current value, an expected voltage value corresponding to the combination of the output terminals 41 to 44 that are supplying power to the loads 61 to 64. The microcomputer 5 acquires a voltage value input from the input terminal 50 and compares it with the expected voltage value acquired from the expected value information 52b to detect an abnormality in the power supply.

[0087] In the power supply system according to the fifth embodiment having the above configuration, the power supply control device 3 detects the output current value from the IPD 4 to the loads 61 to 64. The power supply control device 3 stores an expected value or range in association with the output current value in the storage unit 52, and performs status detection using the expected value or range according to the detected output current value. This allows the power supply control device 3 according to the fifth embodiment to perform status detection using an expected value or range appropriate for changes in the output current value of the IPD 4, and to accurately detect the status of the power supply.

[0088] Furthermore, in the power supply system according to the fifth embodiment, the IPD 4 outputs a sense current according to the output current to the loads 61 to 64, and the microcomputer 5 detects the value of the output current from the IPD 4 to the loads 61 to 64 according to the sense current output by the IPD 4. As a result, the power supply control device 3 according to the fifth embodiment can detect the state according to the output current value of the IPD 4 without having to provide a separate sensor or the like for detecting the output current value of the IPD 4.

[0089] In the fifth embodiment, the IPD 4 outputs a sense current corresponding to the output current value to the loads 61 to 64, and the microcomputer 5 acquires a voltage value corresponding to the sense current, thereby indirectly detecting the output current value of the IPD 4, but this is not limiting. For example, a configuration may be adopted in which a sensor is provided in the current path from the output terminals 41 to 44 of the IPD 4 to the loads 61 to 64, and the microcomputer 5 acquires the current value detected by the sensor. Alternatively, for example, a configuration may be adopted in which a sensor is provided in the current path from the power supply to the IPD 4, and the microcomputer 5 acquires the power supply current value detected by the sensor, and performs state detection according to the acquired current value.

[0090] The power supply control device 3 according to the fifth embodiment may also include a temperature detection unit 72, as in the second and fourth embodiments. In this case, the microcomputer 5 of the power supply control device 3 according to the fifth embodiment stores a plurality of pieces of expected value information 52b corresponding to a plurality of combinations of output current values ​​and a plurality of temperatures in the storage unit 52. The microcomputer 5 acquires the output current value based on the sense current of the IPD 4 and the temperature detected by the temperature detection unit 72, and reads out the expected value information 52b corresponding to the acquired combination of the output current value and temperature from the storage unit 52.

[0091] Furthermore, other configurations of the power supply system according to embodiment 5 are the same as those of the power supply systems according to embodiments 1 to 4, so the same reference numerals are used for similar parts and detailed explanations are omitted.

[0092] The in-vehicle information processing device includes a computer including a microprocessor, ROM, RAM, etc. The processing unit such as the microprocessor may read and execute computer programs including some or all of the steps of the sequence diagrams or flowcharts shown in Figures 3 and 5 from storage units such as ROM and RAM. The computer programs of these multiple devices can be installed from an external server device, etc. Furthermore, these computer programs are distributed in a state where they are stored on recording media such as CD-ROM, DVD-ROM, and semiconductor memory.

[0093] The embodiments disclosed herein are to be considered as illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the above meaning, and is intended to include all modifications within the meaning and scope of the claims.

[0094] REFERENCE SIGNS LIST 1 Vehicle 3 Power supply control device 4 IPD (supply device) 5 Microcomputer 40 Input terminal 41 to 44 Output terminal 50 Input terminal 51 Processing unit 51a Voltage detection unit 51b State detection unit 52 Memory unit 52a Program 52b Expected value information 53 AD conversion unit 54 Signal output unit 61 to 64 Load 71 Power supply voltage detection unit 72 Temperature detection unit 99 Recording medium 545 Sense output terminal D1 to D4 Diodes R11 to R14 Resistor (first resistor) R2 Resistor (second resistor) R3 Resistor R51, R52 Resistor C1 Capacitor

Claims

1. A power supply control device that controls the supply operation of a supply device that supplies power from a power source to loads connected to multiple output terminals, the power supply control device comprising: a plurality of first resistors that are electrically connected to the multiple output terminals, respectively, and each having a different resistance value; a second resistor that is commonly connected to the multiple first resistors; a first voltage detection unit that detects the voltage between the first resistor and the second resistor; and a status detection unit that detects the status of power supply from the output terminal to the load based on the voltage value detected by the first voltage detection unit.

2. A power supply control device as described in claim 1, further comprising a memory unit that stores an expected value or a range for a voltage value detected by the first voltage detection unit in association with a combination of one or more output terminals among the plurality of output terminals that are supplying power to a corresponding load, and the state detection unit detects a state based on a comparison between the expected value or the range stored in the memory unit and the voltage value detected by the first voltage detection unit.

3. A power supply control device as described in claim 2, further comprising a second voltage detection unit which detects a voltage value of the power supply, wherein the memory unit stores the expected value or the range in association with the voltage value of the power supply, and the state detection unit detects the state based on a comparison between the voltage value detected by the first voltage detection unit and the expected value or the range stored in the memory unit in association with the voltage value detected by the second voltage detection unit.

4. A power supply control device as described in claim 3, further comprising a temperature detection unit that detects temperature, wherein the memory unit stores the expected value or the range in association with the voltage value of the power supply and the temperature, and the state detection unit detects the state based on a comparison between the voltage value detected by the first voltage detection unit and the expected value or the range stored in the memory unit in association with the voltage value detected by the second voltage detection unit and the temperature detected by the temperature detection unit.

5. A power supply control device as described in claim 2, further comprising a current detection unit which detects a current value of a current flowing from the output terminal to the load, wherein the memory unit stores the expected value or the range in association with the current value of the current, and the state detection unit detects a state based on a comparison between the expected value or the range stored in the memory unit in association with the current value detected by the current detection unit and the voltage value detected by the first voltage detection unit.

6. The power supply control device according to claim 5, wherein the supply device outputs a sense current corresponding to the current flowing to the load, and the current detection unit detects a current value of the current flowing to the load according to the sense current output by the supply device.

7. The power supply control device according to claim 2, further comprising a diode provided between the output terminal and the first resistor, and the expected value or the range is determined according to a characteristic of the diode with respect to temperature, voltage or current.

8. The power supply control device according to claim 1, wherein the state detection unit detects the state when the supply of power to the load is switched from on to off or from off to on.

9. The power supply control device according to claim 1, comprising the supply device.

10. A status detection method, comprising: a power supply control device that controls the operation of a supply device that supplies power from a power source to loads connected to a plurality of output terminals, detects a voltage between a plurality of first resistors that are electrically connected to the plurality of output terminals, each having a different resistance value, and a second resistor that is commonly connected to the plurality of first resistors, and detects the status of power supply from the output terminals to the loads based on the detected voltage value.

11. A computer program that causes a computer to control the operation of a power supply device that supplies power from a power source to loads connected to multiple output terminals, respectively, to execute a process of detecting a voltage between a plurality of first resistors that are electrically connected to the multiple output terminals, each having a different resistance value, and a second resistor that is commonly connected to the multiple first resistors, and detecting a state of power supply from the output terminals to the loads based on the detected voltage value.

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