Circuit system and circuit control method
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-02-05
- Publication Date
- 2026-08-13
Smart Images
Figure JP2025003691_13082026_PF_FP_ABST
Abstract
Description
Circuit system and circuit control method
[0001] The present invention relates to a circuit system and a circuit control method.
[0002] There is known an automatic driving in which a computer mounted on a vehicle substitutes at least a part of operations to be performed by a driver of the vehicle. In automatic driving, for example, a steering operation, a braking operation, etc. are automatically executed. Currently, a technique for appropriately supplying power to a load used for automatic driving so that the automatic driving is appropriately continued is being studied.
[0003] For example, in Patent Document 1, a first load circuit in which a lead battery supplies power to a load used for normal driving, a second load circuit in which a lithium ion battery supplies power to a load used for automatic driving, and a circuit interrupter mechanism for connecting or disconnecting the first load circuit and the second load circuit are provided in a vehicle. In the technique described in Patent Document 1, the state of the circuit interrupter mechanism is controlled based on the load state of the second load circuit so that an appropriate voltage is applied to the load used for automatic driving.
[0004] Japanese Unexamined Patent Application Publication No. 2017-177857
[0005] However, in the technique described in Patent Document 1, it is necessary to mount two low-voltage batteries, a lead battery and a lithium ion battery, on the vehicle. When two low-voltage batteries are mounted on the vehicle, compression of the vehicle space, an increase in the vehicle weight, an increase in cost, etc. occur. Therefore, a technique for appropriately continuing automatic driving using a single low-voltage battery is desired.
[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a circuit system and a circuit control method for appropriately continuing automatic driving using a single low-voltage battery.
[0007] To achieve the above objective, the circuit system according to the present invention comprises a first load circuit, a second load circuit, and a switch circuit. The first load circuit comprises a DC / DC converter that transforms the DC voltage output by a high-voltage battery mounted on the vehicle, and a plurality of first loads connected to the DC / DC converter. The second load circuit comprises a low-voltage battery mounted on the vehicle and a plurality of second loads connected to the low-voltage battery. The switch circuit connects the first load circuit and the second load circuit, and separates the first load circuit and the second load circuit if an abnormality in the power supply voltage occurs in the first load circuit or the second load circuit. The plurality of first loads include first automatic driving loads which are loads for realizing a first function related to automatic driving, and the plurality of second loads include second automatic driving loads which are loads for realizing a second function that corresponds to the first function related to automatic driving. If the first load circuit and the second load circuit are separated due to an abnormality during the execution of automatic driving, automatic driving is continued using the available function among the first and second functions.
[0008] According to the present invention, autonomous driving can be properly maintained using a single low-voltage battery.
[0009] This is a diagram of the circuit system according to Embodiment 1. This is a diagram of the switch circuit according to Embodiment 1. This is an explanatory diagram of the load distribution method according to Embodiment 1. This is an explanatory diagram of the operation of the circuit system according to Embodiment 1 when it starts up. This is an explanatory diagram of the operation when an abnormality occurs in the first load circuit of the circuit system according to Embodiment 1. This is an explanatory diagram of the operation when an abnormality occurs in the second load circuit of the circuit system according to Embodiment 1. This is a flowchart of the power supply control process executed by the circuit system according to Embodiment 1. This is a flowchart of the battery abnormality monitoring process executed by the circuit system according to Embodiment 1. This is a diagram of the circuit system according to Embodiment 2. This is a flowchart of the power supply control process executed by the circuit system according to Embodiment 2. This is a diagram of the circuit system according to Embodiment 3. This is a diagram of the circuit system according to Embodiment 4.
[0010] Embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.
[0011] (Embodiment 1) Figure 1 is a diagram of the configuration of a circuit system 1000 according to Embodiment 1. The circuit system 1000 is installed in a vehicle such as an electric vehicle or a hybrid vehicle. The circuit system 1000 is connected to a high-voltage battery 10 and a motor 20 via a power relay 30 and includes a first load circuit 100, a second load circuit 200, and a switch circuit 300.
[0012] The high-voltage battery 10 is a secondary battery installed in the vehicle and supplies power to loads with relatively high power consumption. The high-voltage battery 10 outputs a voltage of several hundred volts. The high-voltage battery 10 supplies power to the motor 20, DC / DC converter 110, etc. The high-voltage battery 10 also stores power supplied from the motor 20, an external power source (not shown), etc. The high-voltage battery 10 is, for example, a lithium-ion battery.
[0013] The motor 20 is mounted on the vehicle and functions as both an electric motor and a generator. When functioning as an electric motor, the motor 20 generates torque using power supplied from the high-voltage battery 10, and drives the vehicle with the generated torque. The torque generated by the motor 20 is transmitted to a rotating mechanism (not shown) connected to the wheels. When functioning as a generator, the motor 20 converts the rotational force supplied from the rotating mechanism into electricity and supplies the resulting electricity to the high-voltage battery 10.
[0014] The power relay 30 is a switch for safely controlling high voltage and high current. The state of the power relay 30 is controlled, for example, by a body control module (not shown). The body control module is an ECU (Electronic Control Unit) that controls the functions of the entire vehicle body. For example, the body control module turns on the power relay 30 when the vehicle ignition is on and turns off the power relay 30 when the ignition is off. In this embodiment, turning a relay, switch, etc., into a conductive state is called "on," and turning a relay, switch, etc., into an insulated state is called "off." A conductive state is a state in which current is allowed to flow between two circuits. A non-conductive state is a state in which current is not allowed to flow between two circuits.
[0015] The first load circuit 100 includes a DC / DC converter 110, an ADAS (Advanced Driver Assistance Systems) load 121, a brake load 122, a power steering load 123, a driving load 124, a fuse 131, a fuse 132, a fuse 133, a fuse 134, and a voltmeter 140.
[0016] The DC / DC converter 110 transforms the DC voltage output by the high-voltage battery 10 mounted on the vehicle. The DC / DC converter 110 converts the high voltage of several hundred volts output by the high-voltage battery 10 to a low voltage of about 10 volts and outputs it. The output state, output voltage, etc. of the DC / DC converter 110 are controlled by the driving load 124.
[0017] The ADAS load 121, brake load 122, power steering load 123, and driving load 124 are examples of first loads connected to the DC / DC converter 110 and basically operating on power supplied from the DC / DC converter 110. The first loads include an ECU, actuators, sensors, etc. The ECU includes, for example, a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. Each ECU can communicate with other ECUs, various control circuits, etc. via a communication network (not shown) installed in the vehicle.
[0018] The ADAS load 121 is a load for controlling an advanced driver-assistance system that assists the driver's operation of the vehicle. The ADAS load 121 includes an ADAS ECU that comprehensively controls the advanced driver-assistance system. The ADAS ECU controls various ECUs related to autonomous driving based on information such as infrared sensors and acceleration sensors.
[0019] The autonomous driving in this embodiment is a concept that encompasses all levels of autonomous driving: Level 1 autonomous driving which corresponds to driver assistance, Level 2 autonomous driving which corresponds to partial driving automation, Level 3 autonomous driving which corresponds to conditional driving automation, Level 4 autonomous driving which corresponds to high driving automation, and Level 5 autonomous driving which corresponds to full driving automation. In the autonomous driving in this embodiment, at least some of the operations that the vehicle driver would normally perform are performed on behalf of the vehicle driver.
[0020] The brake load 122 is a load for controlling the vehicle's brakes. The brake load 122 includes a brake ECU for controlling the brakes, a brake actuator, and the like. The brake ECU assists or takes over the driver's brake operation according to the control of the ADAS ECU. The brake ECU controls the brake actuator to appropriately decelerate or stop the vehicle.
[0021] The power steering load 123 is a load for controlling the vehicle's power steering. The power steering load 123 includes a power steering ECU for controlling the power steering, a power steering actuator, and the like. The power steering ECU assists or takes over the driver's steering operation according to the control of the ADAS ECU. The power steering ECU controls the power steering actuator to move the vehicle in the appropriate direction. Generally, loads for controlling power steering are often loads that are controlled to maintain a constant power consumption. The power steering load 123 in this embodiment is a load that is controlled to maintain a constant power consumption, and is a load in which the input current decreases as the input voltage increases.
[0022] The driving load 124 is a load used to control the vehicle's movement. The driving load 124 includes a P (Power) / T (Train) ECU that controls the vehicle's powertrain. The P / T ECU assists or takes over the driver's accelerator operation according to the control of the ADAS ECU. The P / T ECU controls the motor 20 to drive the vehicle. The P / T ECU also controls the DC / DC converter 110 when the ignition is on and the DC / DC converter 110 is operational. For example, the P / T ECU sends a control signal to the DC / DC converter 110 to adjust the voltage transformation ratio of the DC / DC converter 110, causing the DC / DC converter 110 to output a voltage of about 14V. The driving load 124 is an example of a converter control circuit.
[0023] Fuses 131, 132, 133, and 134 are connected to the ADAS load 121, brake load 122, power steering load 123, and driving load 124, respectively. Each of the fuses 131, 132, 133, and 134 blows itself to protect the circuit when an excessive current flows through its corresponding load.
[0024] The voltmeter 140 measures the first power supply voltage, which is the voltage applied to the first load and is the power supply voltage of the first load circuit 100. The first power supply voltage is basically the output voltage of the DC / DC converter 110. The voltmeter 140 supplies voltage information indicating the first power supply voltage obtained by measurement to various ECUs, various control circuits, etc.
[0025] The second load circuit 200 includes a battery device 210, an ADAS load 221, a brake load 222, a power steering load 223, a fuse 231, a fuse 232, a fuse 233, and a voltmeter 240. The battery device 210 has a power storage function for storing power and a discharge function for releasing the stored power. The battery device 210 includes a low-voltage battery 211, a relay 212, and a control circuit 213.
[0026] The low-voltage battery 211 is a secondary battery mounted in the vehicle and supplies power to a load with relatively low power consumption. The low-voltage battery 211 outputs a voltage of about 10 volts. The low-voltage battery 211 supplies power to the second load, which will be described later. In principle, the output voltage of the DC / DC converter 110 is controlled to be slightly higher than the output voltage of the low-voltage battery 211. Therefore, the low-voltage battery 211 can store the power supplied from the DC / DC converter 110. The low-voltage battery 211 is, for example, a lithium-ion battery.
[0027] Relay 212 is installed between the low-voltage battery 211 and multiple second loads. Relay 212 operates according to the control of the control circuit 213. When relay 212 is ON, power can be supplied from or stored in the low-voltage battery 211. When relay 212 is OFF, power can no longer be supplied from or stored in the low-voltage battery 211. Relay 212 is controlled by the control circuit 213 to be ON or OFF at the appropriate timing.
[0028] The control circuit 213 controls the operation of the battery device 210. Specifically, the control circuit 213 supplies a control signal to the relay 212 to control its operation, switching the relay 212 between on and off. The control circuit 213 also has a diagnostic function to diagnose whether the relay 212 is operating normally. For example, if the control circuit 213 sends a control signal to the relay 212 to instruct it to turn on, and no current flows between the ends of the relay 212, it diagnoses that a fault has occurred in the relay 212 that prevents it from turning on. The control circuit 213 is an example of a relay control circuit.
[0029] The ADAS load 221, brake load 222, power steering load 223, etc., are examples of second loads that operate on power supplied from the low-voltage battery 211. The second loads include the ECU, actuators, sensors, etc.
[0030] The ADAS load 221 is a load for controlling the advanced driver assistance system that assists the driver's operation of the vehicle. The ADAS load 221 basically has the same function as the ADAS load 121. The brake load 222 is a load for controlling the vehicle's brakes. The brake load 222 basically has the same function as the brake load 122. The power steering load 223 is a load for controlling the vehicle's power steering. The power steering load 223 basically has the same function as the power steering load 123.
[0031] Fuses 231, 232, and 233 are provided for the ADAS load 221, the brake load 222, and the power steering load 223, respectively. Each of the fuses 231, 232, and 233 blows itself to protect the circuit when an excessive current flows through the corresponding load.
[0032] The voltmeter 240 measures the second power supply voltage, which is the voltage applied to the second load and is the power supply voltage of the second load circuit 200. The second power supply voltage is basically the output voltage of the DC / DC converter 110 when the switch circuit 300 is on, and the output voltage of the low-voltage battery 211 when the switch circuit 300 is off. The voltmeter 240 supplies voltage information indicating the second power supply voltage obtained by measurement to various ECUs, various control circuits, etc.
[0033] The switch circuit 300 hardware-connects or disconnects the first load circuit 100 and the second load circuit 200. More specifically, the switch circuit 300 connects or disconnects the positive output terminal of the DC / DC converter 110 and the positive output terminal of the low-voltage battery 211. The switch circuit 300 is a circuit that includes a semiconductor switch and is capable of high-speed switching. Under normal circumstances, the switch circuit 300 connects the first load circuit 100 and the second load circuit 200. If an abnormality occurs in the power supply voltage of the first load circuit 100 or the second load circuit 200, the switch circuit 300 disconnects the first load circuit 100 and the second load circuit 200. For example, if the first power supply voltage is outside the first reference voltage range, the switch circuit 300 determines that an abnormality has occurred in the power supply voltage of the first load circuit 100 or the second load circuit 200.
[0034] As shown in Figure 2, the switch circuit 300 comprises an n-channel MOSFET (Metal Oxide Semiconductor Field Effect Transistor) 310, an n-channel MOSFET 320, a shunt resistor 330, a voltmeter 340, and a control circuit 350. The n-channel MOSFETs 310 and 320 are semiconductor devices that allow current to flow between their source and drain when the gate voltage exceeds the threshold voltage. The gate voltage is controlled by the control circuit 350.
[0035] The shunt resistor 330 is a resistor used to detect the magnitude of the current flowing through the switch circuit 300. The voltmeter 340 detects the voltage across the shunt resistor 330. The voltmeter 340 supplies voltage information indicating the voltage obtained from the measurement to the control circuit 350.
[0036] The control circuit 350 switches the n-channel MOSFETs 310 and 320 on and off. For example, the control circuit 350 turns on the n-channel MOSFET 310 by applying a voltage exceeding the threshold voltage to its gate. Conversely, the control circuit 350 turns off the n-channel MOSFET 310 by applying a voltage below the threshold voltage to its gate. Since the same voltage is applied to the gate voltage of the n-channel MOSFET 310 and the gate voltage of the n-channel MOSFET 320, the state of the n-channel MOSFET 310 and the n-channel MOSFET 320 are the same. The control circuit 350 can communicate with various ECUs via a communication network.
[0037] Next, referring to Figure 3, a method for distributing the load mounted on the vehicle into a first load and a second load will be explained. First, the multiple first loads included in the first load circuit 100 include a first autonomous driving load, which is a load for realizing a first function related to autonomous driving. In addition, the multiple second loads included in the second load circuit 200 include a second autonomous driving load, which is a load for realizing a second function that corresponds to the first function related to autonomous driving.
[0038] The first function is a function related to autonomous driving. Functions related to autonomous driving include ADAS control function, automatic braking function, automatic steering function, autonomous driving function, meter display function, head-up display function, left headlight illumination function, right headlight illumination function, etc. The second function is a function related to autonomous driving and corresponds to the first function. The second function may be the same as the first function. For example, if the first function is the ADAS control function, the second function may be the ADAS control function. The second function may be a function that replaces the first function. For example, if the first function is the meter display function, the second function may be the head-up display function. Also, for example, if the first function is the left headlight illumination function, the second function may be the right headlight illumination function.
[0039] In this embodiment, if an abnormality occurs in the power supply voltage of the first load circuit 100 or the second load circuit 200, the first load circuit 100 and the second load circuit 200 are separated. Therefore, the operation of the load circuit that does not have the cause of the abnormality can continue. For example, if the first load circuit 100 has the cause of the abnormality, the supply of power to the second automatic operation load is maintained in the second load circuit 200, and the second function is maintained. Also, for example, if the second load circuit 200 has the cause of the abnormality, the supply of power to the first automatic operation load is maintained in the first load circuit 100, and the first function is maintained. Therefore, even if either of the load circuits has the cause of the abnormality, at least one of the first and second functions is maintained, and at least a part of the functions of automatic operation are maintained.
[0040] In this embodiment, the first load circuit 100 includes at least one first automatic driving load, and the second load circuit 200 includes at least one second automatic driving load. Specifically, the first load circuit 100 includes, as first automatic driving loads, an ADAS load 121 for realizing ADAS control function, a brake load 122 for realizing automatic braking function, a power steering load 123 for realizing automatic steering function, a driving load 124 for realizing automatic driving function, a meter display load (not shown) for realizing meter display function, etc. In Figure 3, ADAS1, EPS1, Brake1, P / T, and Meter represent the ADAS load 121, brake load 122, power steering load 123, driving load 124, and meter display load, respectively.
[0041] Furthermore, the second load circuit 200 includes, as a second load for autonomous driving, an ADAS load 221 for realizing ADAS control function, a brake load 222 for realizing automatic braking function, a power steering load 223 for realizing automatic steering function, and a head-up display load (not shown) for realizing head-up display function. In Figure 3, ADAS2, EPS2, Brake2, and HUD represent the ADAS load 221, brake load 222, power steering load 223, and head-up display load, respectively. In Figure 3, loads enclosed by dashed lines are either first autonomous driving loads or second autonomous driving loads. Note that there is no second autonomous driving load corresponding to the driving load 124, which includes the P / T ECU and is a first autonomous driving load.
[0042] Here, the DC / DC converter 110 has an output characteristic in which the output voltage is maintained as long as the output current is small, but the output voltage drops sharply when the output current exceeds a certain magnitude. Figure 3 shows an example in which the output voltage is maintained at 14V as long as the output current is less than 200A, and when the output current exceeds 200A, the output voltage drops sharply from 14V. On the other hand, the low-voltage battery 211 has an output characteristic in which the output voltage gradually decreases as the output current increases. Figure 3 shows an example in which the output voltage gradually decreases from 13V as the output current increases.
[0043] Here, if the second load circuit 200 has a cause for abnormality, the DC / DC converter 110 in the first load circuit 100 needs to supply current to the first load on its own. Therefore, it is desirable that the first maximum current sum, which is the sum of the maximum currents flowing to each of the multiple first loads provided in the first load circuit 100, is smaller than the current limit, which is the upper limit of the current that the DC / DC converter 110 can supply. This current limit corresponds to the rated current value of the DC / DC converter 110. In Figure 3, "normal value" indicates the "value of the current that flows under normal circumstances," and "maximum value" indicates the "value of the maximum current that flows transiently."
[0044] Thus, the current that the DC / DC converter 110 can pass is limited. Therefore, when the load to be mounted on the vehicle increases and it is difficult to increase the first load, it is preferable to increase the second load. That is, when the load to be mounted on the vehicle increases, a load through which more load or more current flows is added to the second load circuit 200 rather than the first load circuit 100. In this case, the second maximum current total value, which is the total value of the maximum currents flowing through each of the plurality of second loads included in the second load circuit 200, is larger than the first maximum current total value. In the example shown in FIG. 3, 185 A, which is the first maximum current total value, is smaller than 200 A, which is the current upper limit value, and smaller than 188 A, which is the second maximum current total value. Note that these numerical values are merely examples, and it is sufficient that the above magnitude relationship holds for the numerical values such as the first maximum current total value, the current upper limit value, the second maximum current total value, and the like.
[0045] Next, referring to FIG. 4, the operation at the time of starting the circuit system 1000 will be described. When starting the circuit system 1000, it is when the ignition is turned on and the power relay 30 is turned on. Also, in FIG. 4, illustration of some components included in the circuit system 1000 is omitted.
[0046] First, when the ignition is off, the power relay 30 is off. Therefore, power is not supplied from the high-voltage battery 10 to the DC / DC converter 110, and the DC / DC converter 110 is not started. Here, when the ignition is off, the switch circuit 300 is in the on state. For this reason, the low-voltage battery 211 supplies power to the second load and also supplies power to the first load via the switch circuit 300. At this time, power is also supplied to the P / T ECU included in the traveling load 124, which is the first load.
[0047] When the ignition is turned on, the power relay 30 is turned on. Therefore, power is supplied from the high-voltage battery 10 to the DC / DC converter 110, enabling the DC / DC converter 110 to start. Thus, the P / T ECU starts controlling the DC / DC converter 110. As a result, the DC / DC converter 110 supplies power to the first load and, via the switch circuit 300, supplies power to the second load and the low-voltage battery 211. Thereby, the low-voltage battery 211 is charged. When the current flowing through the first load and the second load cannot be fully provided by only the DC / DC converter 110, current also flows from the low-voltage battery 211 to the first load and the second load.
[0048] After the low-voltage battery 211 is fully charged, the diagnostic process of the switch circuit 300 is executed. For example, the control circuit 350 turns off the n-channel MOSFET 310 and the n-channel MOSFET 320, turning off the switch circuit 300. Then, based on the voltage information supplied from the voltmeter 340, the control circuit 350 determines whether current is flowing through the shunt resistor 330. For example, the control circuit 350 determines whether the voltage across both ends of the shunt resistor 330 indicated by the voltage information is equal to or higher than the reference voltage. When the control circuit 350 determines that no current is flowing through the shunt resistor 330, it determines that the switch circuit 300 is operating normally in the separation mode. On the other hand, when the control circuit 350 determines that current is flowing through the shunt resistor 330, it determines that the switch circuit 300 is not operating normally in the separation mode.
[0049] Next, the control circuit 350 turns on the n-channel MOSFETs 310 and 320, and turns on the switch circuit 300. Then, the control circuit 350 determines whether or not current is flowing through the shunt resistor 330. If the control circuit 350 determines that current is flowing through the shunt resistor 330, it determines that the switch circuit 300 is connecting normally. On the other hand, if the control circuit 350 determines that no current is flowing through the shunt resistor 330, it determines that the switch circuit 300 is not connecting normally. The confirmation of separation operation and the confirmation of connection operation may be performed multiple times. Once the separation operation and connection operation are determined to be normal, automatic operation is permitted, and the operation mode can be switched to the automatic operation mode.
[0050] Next, the operation of the circuit system 1000 when an abnormality occurs in the power supply voltage will be explained with reference to Figures 5 and 6. In Figures 5 and 6, some components of the circuit system 1000 are not shown. Note that the explanation in Figures 5 and 6 is based on the assumption that the ignition is on and the operating mode is automatic operation mode.
[0051] First, with reference to Figure 5, the operation of the first load circuit 100 of the circuit system 1000 when an abnormality occurs will be explained. Figure 5 shows an example in which a short-circuit failure occurs in the ADAS load 121, causing a large current to flow from the DC / DC converter 110 to the ADAS load 121. In this case, the first power supply voltage drops and falls outside the first reference voltage range. The first reference voltage range is, for example, from 13V to 15V.
[0052] At this point, the switch circuit 300 is turned off, and the first load circuit 100 and the second load circuit 200 are separated. As a result, a large current continues to flow from the DC / DC converter 110 to the ADAS load 121, but current flows from the low-voltage battery 211 to the second load. In this case, the supply of power to the first automatic driving load is not guaranteed, but the supply of power to the second automatic driving load is guaranteed. Therefore, even if the first function is lost, the second function corresponding to the first function is not lost, and automatic driving is maintained. For example, even if the ADAS control function by the ADAS load 121 is stopped, the ADAS control function by the ADAS load 221 is maintained.
[0053] If a large current continues to flow from the DC / DC converter 110 to the ADAS load 121, the fuse 131 connected to the ADAS load 121 will melt. As a result, current will no longer flow from the DC / DC converter 110 to the ADAS load 121, and the first power supply voltage will recover to within the first reference voltage range. At this point, the switch circuit 300 is turned on, and the first load circuit 100 and the second load circuit 200 are connected. Power is then supplied from the DC / DC converter 110 to the first load, the second load, the low-voltage battery 211, etc.
[0054] Next, referring to Figure 6, the operation of the second load circuit 200 of the circuit system 1000 when an abnormality occurs will be described. Figure 6 shows an example in which a short-circuit failure occurs in the ADAS load 221, causing a large current to flow from the DC / DC converter 110 to the ADAS load 221. In this case, the second power supply voltage drops, and the second power supply voltage falls outside the second reference voltage range. The second reference voltage range is, for example, from 12V to 15V.
[0055] At this point, the switch circuit 300 is turned off, and the first load circuit 100 and the second load circuit 200 are separated. As a result, a large current no longer flows from the DC / DC converter 110 to the ADAS load 221, and current flows from the DC / DC converter 110 to the first load. Meanwhile, a large current flows from the low-voltage battery 211 to the ADAS load 221. As a result, the second power supply voltage drops, and the second power supply voltage falls outside the second reference voltage range. In this case, the supply of power to the second automatic operation load is not guaranteed, but the supply of power to the first automatic operation load is guaranteed. Therefore, even if the second function is lost, the first function corresponding to the second function is not lost, and automatic operation is maintained. For example, even if the ADAS control function by the ADAS load 221 is stopped, the ADAS control function by the ADAS load 121 is maintained.
[0056] In this embodiment, when the first load circuit 100 and the second load circuit 200 are separated, the total current flowing from the DC / DC converter 110 to each of the multiple first loads is controlled so as not to exceed the current upper limit value corresponding to the rated current of the DC / DC converter 110. As described above, the power steering load 123 is a load in which the input current decreases as the input voltage increases. Therefore, the P / T ECU increases the output voltage of the DC / DC converter 110 to reduce the current flowing from the DC / DC converter 110 to the power steering load 123.
[0057] If a large current continues to flow from the low-voltage battery 211 to the ADAS load 221, the fuse 231 connected to the ADAS load 221 will melt. As a result, current will no longer flow from the low-voltage battery 211 to the ADAS load 221, the second power supply voltage will rise, and the second power supply voltage will fall within the second reference voltage range. At this point, the switch circuit 300 is turned on, and the first load circuit 100 and the second load circuit 200 are connected. Then, power is supplied from the DC / DC converter 110 to the first load, the second load, the low-voltage battery 211, etc.
[0058] Next, the power supply control process performed by the circuit system 1000 will be described with reference to the flowchart in Figure 7.
[0059] First, the circuit system 1000 determines whether the ignition is on or off (step S101). For example, the control circuit 350 obtains information indicating the ignition status from the body control module that manages the ignition status, and determines whether the ignition is on or off. If the circuit system 1000 determines that the ignition is on (step S101: YES), it then determines whether the driving mode is automatic driving mode or off (step S102). For example, the control circuit 350 obtains information indicating the driving mode from the ECU (not shown) that manages the driving mode, and determines whether the driving mode is automatic driving mode or off.
[0060] When the circuit system 1000 determines that the operating mode is automatic operation mode (step S102: YES), it determines whether or not an abnormality in the power supply voltage has occurred (step S103). For example, the control circuit 350 determines whether or not the first power supply voltage is within the range of the first reference voltage. When the circuit system 1000 determines that an abnormality in the power supply voltage has occurred (step S103: YES), it separates the two load circuits (step S104). For example, the control circuit 350 turns off the n-channel MOSFET 310 and the n-channel MOSFET 320.
[0061] After completing the process in step S104, the circuit system 1000 determines whether the second power supply voltage is abnormal (step S105). For example, the control circuit 350 determines whether the second power supply voltage is outside the second reference voltage range. If the circuit system 1000 determines that the second power supply voltage is abnormal (step S105: YES), it increases the output voltage of the DC / DC converter 110 (step S106). For example, the P / T ECU increases the output voltage of the DC / DC converter 110 from 14V to 15V.
[0062] If the circuit system 1000 determines that the second power supply voltage is not abnormal (step S105: NO), or if it has completed the process in step S106, it determines whether the abnormality in the power supply voltage has been resolved (step S107). For example, the control circuit 350 determines whether the first power supply voltage is within the first reference voltage range and whether the second power supply voltage is within the second reference voltage range.
[0063] If the circuit system 1000 determines that the abnormality in the power supply voltage has not been resolved (step S107: NO), it determines whether the operating mode has switched to manual operating mode (step S108). If the circuit system 1000 determines that the operating mode has not switched to manual operating mode (step S108: NO), it determines whether the ignition is off (step S109). If the circuit system 1000 determines that the ignition is not off (step S109: NO), it returns to step S107.
[0064] The circuit system 1000 connects the two load circuits (step S110) when it determines that the abnormality in the power supply voltage has been resolved (step S107: YES), when it determines that the operating mode has switched to manual operation mode (step S108: YES), or when it determines that the ignition is off (step S109: YES). For example, the control circuit 350 turns on the n-channel MOSFET 310 and the n-channel MOSFET 320. After completing the process in step S110, the circuit system 1000 returns the output voltage of the DC / DC converter 110 to its original voltage (step S111). For example, the P / T ECU changes the output voltage of the DC / DC converter 110 from 15V to 14V.
[0065] The circuit system 1000 returns to step S101 if it determines that the ignition is not on (step S101: NO), if it determines that the operating mode is not automatic operation mode (step S102: NO), if it determines that there is no abnormality in the power supply voltage (step S103: NO), or if the processing in step S111 is completed.
[0066] Next, with reference to Figure 8, the battery abnormality monitoring process performed by the circuit system 1000 according to this embodiment will be described. First, the circuit system 1000 checks the operation of the relay 212 provided in the battery device 210 (step S201). For example, the control circuit 213 checks whether the relay 212 turns on normally using its self-diagnostic function. After completing the process in step S201, the circuit system 1000 determines whether there is a fault in which the relay 212 does not turn on (step S202).
[0067] If the circuit system 1000 determines that there is no fault preventing relay 212 from turning on (step S202: NO), it completes the battery abnormality monitoring process. If the circuit system 1000 determines that there is a fault preventing relay 212 from turning on (step S202: YES), it prohibits turning the ignition off (step S203). For example, the control circuit 213 notifies the body control module that turning the ignition off should be prohibited. This maintains the supply of power to the first and second loads by the DC / DC converter 110.
[0068] When the circuit system 1000 completes the processing in step S203, it displays an abnormality notification screen (step S204). The abnormality notification screen is a screen that notifies the driver that an abnormality has occurred in the battery device 210. For example, the control circuit 213 notifies the HUD (Head Up Display) ECU of the head-up display load that an abnormality has occurred in the battery device 210. The HUD ECU displays the abnormality notification screen in accordance with this notification. The abnormality notification screen may also show that the vehicle should be brought to a designated location where the abnormality can be resolved, such as a repair shop, the location of the repair shop, the route to the repair shop, etc. The control circuit 213 may also notify a terminal device (not shown) at the repair shop of the vehicle's location, the nature of the malfunction, etc., via a communication device (not shown) installed in the vehicle.
[0069] After completing the process in step S204, the circuit system 1000 determines the vehicle's current location (step S205). For example, the control circuit 213 obtains location information from a GPS (Global Positioning System) receiver (not shown) mounted on the vehicle and determines the vehicle's current location. After completing the process in step S205, the circuit system 1000 determines whether the vehicle has arrived at the repair shop (step S206). For example, the control circuit 213 determines whether the vehicle's current location matches the location of the repair shop indicated by map information stored in a memory device (not shown). The location of the repair shop is an example of a predetermined location.
[0070] If the circuit system 1000 determines that the vehicle has not arrived at the repair shop (step S206: NO), it returns to step S205. If the circuit system 1000 determines that the vehicle has arrived at the repair shop (step S206: YES), it permits the ignition to be turned off (step S207). For example, the control circuit 213 notifies the body control module that it is permitted to turn the ignition on. After completing the process in step S207, the circuit system 1000 completes the battery abnormality monitoring process.
[0071] In this embodiment, if an abnormality in the power supply voltage occurs in the first load circuit 100, which comprises a DC / DC converter 110 and a first automatic operation load, or in the second load circuit 200, which comprises a low-voltage battery 211 and a second automatic operation load, the first load circuit 100 and the second load circuit 200 are separated by the switch circuit 300. Therefore, in this embodiment, even if an abnormality in the power supply voltage occurs, the functions related to automatic operation are maintained. More specifically, if the first load circuit 100 and the second load circuit 200 are separated due to an abnormality during the execution of automatic operation, automatic operation is continued using the available functions of the first and second functions. Thus, according to this embodiment, automatic operation can be appropriately continued using a single low-voltage battery 211.
[0072] Furthermore, in this embodiment, the first maximum total current value is smaller than the current upper limit value, and the second maximum total current value is larger than the first maximum total current value. Therefore, according to this embodiment, even when the power consumption of the load mounted on the vehicle is large, automatic operation can be maintained when the first load circuit 100 and the second load circuit 200 are separated.
[0073] Furthermore, in this embodiment, if an abnormality in the power supply voltage occurs while the operating mode is in automatic operation mode, the first load circuit 100 and the second load circuit 200 are separated. Therefore, according to this embodiment, unnecessary separation of the first load circuit 100 and the second load circuit 200 can be suppressed.
[0074] Furthermore, in this embodiment, the first load circuit 100 includes a converter control circuit that controls the DC / DC converter 110 for each of the multiple first loads. Therefore, according to this embodiment, it is possible to supply appropriate power by the DC / DC converter 110.
[0075] Furthermore, in this embodiment, after the separation of the first load circuit 100 and the second load circuit 200, if an abnormality in the power supply voltage is resolved, the operating mode is switched to manual operation mode, or the ignition is turned off, the first load circuit 100 and the second load circuit 200 are connected. Therefore, according to this embodiment, the unnecessary continued separation of the first load circuit 100 and the second load circuit 200 is suppressed.
[0076] Furthermore, in this embodiment, if the first load circuit 100 and the second load circuit 200 can be separated when the ignition is switched from off to on, the transition to the automatic driving mode is permitted. Therefore, according to this embodiment, the execution of automatic driving that may not be able to continue is suppressed.
[0077] Furthermore, in this embodiment, if a failure is detected in which the relay 212 of the low-voltage battery 211 does not turn on, the ignition is kept on and the DC / DC converter 110 continues to operate until the vehicle is positioned in the designated location. Therefore, according to this embodiment, the inability of the vehicle to move due to a failure of the low-voltage battery 211 is suppressed.
[0078] Furthermore, in this embodiment, the multiple first loads include loads where the input current decreases as the input voltage increases, and if an abnormality occurs due to the second load circuit 200, the output voltage of the DC / DC converter 110 increases. Therefore, according to this embodiment, when an abnormality in the power supply voltage occurs due to the second load circuit 200, a current shortage in the first load circuit 100 is suppressed.
[0079] (Embodiment 2) In Embodiment 1, an example was described in which a current shortage in the first load circuit 100 is suppressed by increasing the output voltage of the DC / DC converter 110. In this embodiment, an example is described in which a current shortage in the first load circuit 100 is suppressed by controlling the operation of the first load. Note that the same configurations and functions as in Embodiment 1 will be omitted or simplified as appropriate.
[0080] Referring to Figure 9, the configuration of the circuit system 1002 according to this embodiment will be described. The circuit system 1002 comprises a first load circuit 102, a second load circuit 200, and a switch circuit 300. The first load circuit 102 comprises a DC / DC converter 110, an ADAS load 121, a brake load 122, a power steering load 123, a driving load 124, a seat heater load 125, a seat blower load 126, a fuse 131, a fuse 132, a fuse 133, a fuse 134, a fuse 135, a fuse 136, a voltmeter 140, a relay 155, and a relay 156.
[0081] The seat heater load 125 and the seat blower load 126 are examples of first loads that operate using power supplied from the DC / DC converter 110. The seat heater load 125 is a load for controlling the temperature of the vehicle's seat. The seat heater load 125 includes a seat heater ECU that controls the heater installed in the seat, the heater installed in the vehicle's seat, and the like.
[0082] The seat blower load 126 is a load for controlling the airflow from the vehicle's seat. The seat blower load 126 includes a seat blower ECU for controlling the blower installed in the seat, and the blower installed in the vehicle's seat. Fuse 135 and fuse 136 are connected to the seat heater load 125 and the seat blower load 126, respectively.
[0083] Relay 155 is connected in series with the seat heater load 125 and the fuse 135, and controls the power supply to the seat heater load 125. When relay 155 is ON, power is supplied to the seat heater load 125, and the seat heater load 125 is operational. When relay 155 is OFF, the power supply to the seat heater load 125 is cut off, and the seat heater load 125 does not operate. Relay 156 is connected in series with the seat blower load 126 and the fuse 136, and controls the power supply to the seat blower load 126. Relay 156 operates in the same way as relay 155. Relays 155 and 156 are controlled by various ECUs, various control circuits, etc. Relays 155 and 156 are, for example, electromagnetic relays.
[0084] Referring to Figure 10, the power supply control process performed by the circuit system 1002 according to this embodiment will be described. In this embodiment, the ignition is kept on, and the operating mode is kept in automatic driving mode.
[0085] First, the circuit system 1002 determines whether or not an abnormality has occurred in the power supply voltage (step S301). If the circuit system 1002 determines that an abnormality has occurred in the power supply voltage (step S301: YES), it separates the two load circuits (step S302). After completing the process in step S302, the circuit system 1002 determines whether or not the second power supply voltage is abnormal (step S303). If the circuit system 1002 determines that the second power supply voltage is abnormal (step S303: YES), it stops the operation of the first load which has a lower priority (step S304).
[0086] For example, the priority of this first load is set higher the more important the function performed by the first load is from the standpoint of safety, convenience, etc. Also, for example, the priority of this first load is set lower the more power the first load consumes. In this embodiment, the ADAS load 121 and the brake load 122, which are the first loads that realize the function of the vehicle to stop automatically, are assigned a high priority. Similarly, the ADAS load 121 and the power steering load 123, which are the first loads that realize the function of the vehicle to turn automatically, are also assigned a high priority. In addition, the driving load 124, which realizes the function of controlling the DC / DC converter 110 in addition to the function of the vehicle to drive, is also assigned a high priority. On the other hand, the seat heater load 125 is assigned a medium priority, and the seat blower load 126 is assigned a low priority. In this case, for example, the ADAS ECU turns off the relay 156 and stops the operation of the seat blower load 126.
[0087] Once the circuit system 1002 completes the processing in step S304, it transitions to low-power automatic driving (step S305). For example, the ADAS ECU switches the control to the brake ECU to suppress sudden braking in order to reduce the power consumption of the brake load 122. The ADAS ECU also switches the control to the power steering ECU to suppress sudden steering in order to reduce the power consumption of the power steering load 123. When the power consumption of the first load decreases, the current flowing from the DC / DC converter 110 to the first load decreases.
[0088] After completing the processing in step S305, the circuit system 1002 determines whether an increase in power consumption in the first load circuit 102 is estimated (step S306). For example, the ADAS ECU determines whether braking, steering, etc., is necessary based on the road conditions ahead of the vehicle, the distance between the vehicle and surrounding vehicles, etc. If the circuit system 1002 determines that an increase in power consumption in the first load circuit 102 is estimated (step S306: YES), it temporarily stops the operation of the first load, which has a medium priority (step S307). For example, the ADAS ECU turns off the relay 155 and stops the operation of the seat heater load 125 until braking, steering, etc., is completed.
[0089] If the circuit system 1002 determines that no increase in power consumption in the first load circuit 102 is estimated (step S306: NO), or if it has completed the processing in step S307, it determines whether the abnormality in the power supply voltage has been resolved (step S308). If the circuit system 1002 determines that the abnormality in the power supply voltage has not been resolved (step S308: NO), it returns to step S306. If the circuit system 1002 determines that the abnormality in the power supply voltage has been resolved (step S308: YES), it restarts the operation of the first load with the lowest priority (step S309). For example, the ADAS ECU turns on the relay 156 to restart the operation of the sheet blower load 126.
[0090] When the circuit system 1002 completes the processing in step S309, it switches to automatic operation at normal power consumption (step S310). For example, the ADAS ECU switches the control to the brake ECU and power steering ECU to normal control. When the circuit system 1002 determines that the second power supply voltage is not abnormal (step S303: NO), it determines whether the abnormality in the power supply voltage has been resolved (step S311). When the circuit system 1002 determines that the abnormality in the power supply voltage has not been resolved (step S311: NO), it returns to step S311. When the circuit system 1002 completes the processing in step S310, or determines that the abnormality in the power supply voltage has been resolved (step S311: YES), it connects the two load circuits (step S312). When the circuit system 1002 determines that no abnormality in the power supply voltage has occurred (step S301: NO), or completes the processing in step S312, it returns to step S301.
[0091] In this embodiment, the multiple first loads include loads that are controlled to reduce power consumption when an abnormality occurs due to the second load circuit 200. Therefore, according to this embodiment, when the first load circuit 102 and the second load circuit 200 are separated, a current shortage in the first load circuit 102 is suppressed.
[0092] Furthermore, in this embodiment, the multiple first loads include loads that are controlled to stop operating if an abnormality occurs due to the second load circuit 200. Therefore, according to this embodiment, when the first load circuit 102 and the second load circuit 200 are separated, the current shortage in the first load circuit 102 is further suppressed.
[0093] (Embodiment 3) In Embodiment 1, an example was described in which the first load circuit 100 and the second load circuit 200 are connected by a switch circuit 300. In this embodiment, an example is described in which the first load circuit 100 and the second load circuit 200 are connected by a switch circuit 300 and a first bypass circuit 410. Note that the same configurations and functions as in Embodiments 1 and 2 will be omitted or simplified as appropriate.
[0094] Referring to Figure 11, the configuration of the circuit system 1003 according to this embodiment will be described. The circuit system 1003 comprises a first load circuit 100, a second load circuit 200, a switch circuit 300, and a first bypass circuit 410. The first bypass circuit 410 is provided in parallel with the switch circuit 300 between the first load circuit 100 and the second load circuit 200. The first bypass circuit 410 comprises a relay 411 and a control circuit 412.
[0095] Relay 411 connects or disconnects the first load circuit 100 and the second load circuit 200 according to the control of the control circuit 412. Relay 411 is, for example, an electromagnetic relay. The control circuit 412 controls relay 411. For example, if the first load circuit 100 and the second load circuit 200 are not connected due to a malfunction in the switch circuit 300, the control circuit 412 turns on relay 411. The control circuit 412 communicates with various ECUs, various control circuits, etc.
[0096] In this embodiment, the first bypass circuit 410, which is provided in parallel with the switch circuit 300, includes a relay 411 that connects the first load circuit 100 and the second load circuit 200 if the first load circuit 100 and the second load circuit 200 are not connected due to a malfunction in the switch circuit 300. Therefore, according to this embodiment, even if the above malfunction occurs in the switch circuit 300, the first load circuit 100 and the second load circuit 200 can be connected. As a result, the inability of the low-voltage battery 211 to be charged is suppressed.
[0097] (Embodiment 4) In Embodiment 1, an example was described in which the first load circuit 100 and the second load circuit 200 are connected by a switch circuit 300. In this embodiment, an example is described in which the first load circuit 100 and the second load circuit 200 are connected by a switch circuit 300 and a second bypass circuit 420. Note that the same configurations and functions as in Embodiments 1-3 will be omitted or simplified as appropriate.
[0098] Referring to Figure 12, the configuration of the circuit system 1004 according to this embodiment will be described. The circuit system 1004 includes a first load circuit 100, a second load circuit 200, a switch circuit 300, and a second bypass circuit 420. The second bypass circuit 420 is provided in parallel with the switch circuit 300 between the first load circuit 100 and the second load circuit 200. The second bypass circuit 420 includes a diode 421 and a resistor 422. The diode 421 allows current to flow from the second load circuit 200 to the first load circuit 100. The resistor 422 is connected in series with the diode 421.
[0099] The second bypass circuit 420 allows current to flow from the second load circuit 200 to the first load circuit 100, but does not allow current to flow from the first load circuit 100 to the second load circuit 200. The resistance of the second bypass circuit 420 is higher than the resistance of the switch circuit 300. Therefore, when the switch circuit 300 is on, basically no current flows through the second bypass circuit 420. On the other hand, when the switch circuit 300 is off, current flows through the second bypass circuit 420 when the second power supply voltage is higher than the first power supply voltage.
[0100] In this configuration, when the vehicle is started, power needs to be supplied from the low-voltage battery 211 of the second load circuit 200 to the P / T ECU of the driving load 124 of the first load circuit 100 in order to operate the DC / DC converter 110. However, if the switch circuit 300 fails to turn on, power cannot be supplied from the low-voltage battery 211 to the P / T ECU via the switch circuit 300. In this embodiment, in such a case, power can be supplied from the low-voltage battery 211 to the P / T ECU via the second bypass circuit 420.
[0101] In this embodiment, the second bypass circuit 420, which is provided in parallel with the switch circuit 300, includes a diode 421 that allows current to flow from the second load circuit 200 to the first load circuit 100, and a resistor 422 connected in series with the diode 421. Therefore, according to this embodiment, even if an abnormality occurs in which the switch circuit 300 is not turned off, current can still flow from the second load circuit 200 to the first load circuit 100. As a result, the DC / DC converter 110 can be reliably operated when the vehicle is started.
[0102] (Modifications) Although embodiments have been described above, various modifications and applications are possible. It is arbitrary which parts of the configuration, function, and operation described in the above embodiments are adopted. In addition to the configuration, function, and operation described above, further configurations, functions, and operations may be adopted. Furthermore, the configurations, functions, and operations described in the above embodiments can be freely combined.
[0103] The entity that performs the processing described in Embodiment 1-4 is not limited to the entity described in Embodiment 1-4. Any of the various ECUs, various control circuits, etc., provided in the circuit system 1000, circuit system 1002, etc., may perform the above processing.
[0104] This invention allows for various embodiments and modifications without departing from the broad spirit and scope of the invention. Furthermore, the embodiments described above are for illustrative purposes only and do not limit the scope of the invention. In other words, the scope of the invention is indicated not by the embodiments, but by the claims. Various modifications made within the scope of the claims and the equivalent scope of the meaning of the invention are considered to be within the scope of the invention.
[0105] 10 High-voltage battery, 20 Motor, 30 Power relay, 100, 102 First load circuit, 110 DC / DC converter, 121, 221 ADAS load, 122, 222 Brake load, 123, 223 Power steering load, 124 Driving load, 125 Seat heater load, 126 Seat blower load, 131, 132, 133, 134, 135, 136, 231, 232, 233 Fuses, 140, 240, 340 Voltmeter, 155, 156, 212, 411 Relay, 213, 350, 412 Control circuit, 200 Second load circuit, 210 Battery device, 211 Low-voltage battery, 300 Switch circuit, 310, 320 n-channel MOSFET, 330 Shunt resistor, 410 First bypass circuit, 420; Second bypass circuit, 421; Diode, 422; Resistors, 1000, 1002, 1003, 1004; Circuit system.
Claims
1. A circuit system comprising: a first load circuit comprising a DC / DC converter that transforms the DC voltage output by a high-voltage battery mounted on a vehicle and a plurality of first loads connected to the DC / DC converter; a second load circuit comprising a low-voltage battery mounted on the vehicle and a plurality of second loads connected to the low-voltage battery; and a switch circuit that connects the first load circuit and the second load circuit and separates the first load circuit and the second load circuit when an abnormality in the power supply voltage occurs in the first load circuit or the second load circuit, wherein the plurality of first loads include a first automatic driving load which is a load for realizing a first function related to automatic driving, and the plurality of second loads include a second automatic driving load which is a load for realizing a second function that is related to automatic driving and corresponds to the first function, and when the first load circuit and the second load circuit are separated due to the occurrence of the abnormality during the execution of automatic driving, the automatic driving is continued using the available function of the first function and the second function.
2. The circuit system according to claim 1, wherein the first maximum current sum, which is the sum of the maximum currents flowing through each of the plurality of first loads, is less than the current limit, which is the upper limit of the current that the DC / DC converter can supply, and the second maximum current sum, which is the sum of the maximum currents flowing through each of the plurality of second loads, is greater than the first maximum current sum.
3. The circuit system according to claim 1 or 2, wherein the switch circuit separates the first load circuit and the second load circuit when the abnormality occurs while the operating mode is an automatic operation mode in which the automatic operation is performed, and does not separate the first load circuit and the second load circuit when the abnormality occurs while the operating mode is a manual operation mode in which the automatic operation is not performed.
4. The circuit system according to claim 3, wherein the plurality of first loads include a converter control circuit that starts controlling the DC / DC converter with power supplied from the low-voltage battery via the switch circuit when the ignition is switched from off to on and the DC / DC converter becomes operational, and the DC / DC converter supplies power to the plurality of first loads in accordance with the control by the converter control circuit.
5. The circuit system according to claim 4, wherein the switch circuit connects the first load circuit and the second load circuit when the resolution of the abnormality, the transition of the operating mode to the manual operating mode, or the turning off of the ignition is detected after the separation of the first load circuit and the second load circuit.
6. The circuit system according to claim 4 or 5, wherein the switch circuit attempts to separate the first load circuit and the second load circuit when the ignition is switched from off to on, and if the switch circuit can separate the first load circuit and the second load circuit, the transition of the operating mode to the automatic operating mode is permitted.
7. The circuit system according to any one of claims 4 to 6, wherein the second load circuit comprises a battery device comprising the low-voltage battery, a relay provided between the low-voltage battery and the plurality of second loads, and a relay control circuit for controlling the operation of the relay, and when a fault is detected in which the relay does not turn on, the ignition is kept on and the operation of the DC / DC converter continues until the vehicle moves to a specified position.
8. The circuit system according to any one of claims 4 to 7, wherein the plurality of first loads include loads in which the input current decreases as the input voltage increases, and the converter control circuit increases the output voltage of the DC / DC converter when the occurrence of the abnormality is due to the second load circuit.
9. The circuit system according to any one of claims 1 to 8, wherein the plurality of first loads include loads that are controlled to reduce power consumption when the occurrence of the abnormality is due to the second load circuit.
10. The circuit system according to any one of claims 1 to 9, wherein the plurality of first loads include loads that are controlled to stop operating if the occurrence of the abnormality is due to the second load circuit.
11. The circuit system according to any one of claims 1 to 10, further comprising a first bypass circuit provided in parallel with the switch circuit between the first load circuit and the second load circuit, wherein the first bypass circuit includes a relay for connecting the first load circuit and the second load circuit when the first load circuit and the second load circuit are not connected due to a malfunction of the switch circuit.
12. The circuit system according to any one of claims 1 to 11, further comprising a second bypass circuit provided in parallel with the switch circuit between the first load circuit and the second load circuit, wherein the second bypass circuit comprises a diode that allows current to flow from the second load circuit to the first load circuit, and a resistor connected in series with the diode.
13. A circuit control method comprising: a first load circuit comprising a DC / DC converter that transforms the DC voltage output by a high-voltage battery mounted on a vehicle and a plurality of first loads connected to the DC / DC converter; and a second load circuit comprising a low-voltage battery mounted on the vehicle and a plurality of second loads connected to the low-voltage battery; wherein a switch circuit connecting these components separates the first load circuit and the second load circuit when an abnormality in the power supply voltage occurs in the first load circuit or the second load circuit; the plurality of first loads include first automatic driving loads which are loads for realizing a first function related to automatic driving; the plurality of second loads include second automatic driving loads which are loads for realizing a second function related to automatic driving that corresponds to the first function; and when the first load circuit and the second load circuit are separated due to the occurrence of the abnormality during the execution of automatic driving, the automatic driving is continued using the available function among the first and second functions.