Electronic control device and electronic control method

Abstract

An electronic control device (10) is provided with a control unit (20), a main memory (30), a non-volatile memory (40), and an auxiliary battery (50) that supplies power to the main memory (30). When the voltage of the auxiliary battery (50) becomes equal to or less than a first predetermined voltage, the control unit (20) writes at least a portion of the target data associated with the execution of the program by the control unit (20), which is stored in the main memory (30), into the nonvolatile memory (40).

Description

Technical Field

[0001] This invention relates to an electronic control device and an electronic control method. Background Technology

[0002] The following technology is known: an electronic device having a backup power supply that supplies power to the main memory in a standby state caused by accessory disconnection (ACC-OFF), wherein the electronic device reduces the backup power supply voltage according to the state of the battery (Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-123981 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] However, the technology described in Patent Document 1 has the following problem: if the voltage of the backup power supply drops while the data is being stored in the main memory, the data cannot be maintained in the main memory, which may lead to data corruption in the main memory.

[0008] The problem to be solved by the present invention is to provide an electronic control device and electronic control method that can protect the data associated with the execution program even when the voltage of the auxiliary battery supplying power to the main memory is insufficient during the period when the data associated with the execution program is stored in the main memory.

[0009] Solution for solving the problem

[0010] The present invention solves the above-mentioned problem by writing at least a portion of the object data associated with the executable program stored in the main memory into non-volatile memory when the voltage of the auxiliary battery drops below a first predetermined voltage.

[0011] The effects of the invention

[0012] According to the present invention, even if the voltage of the auxiliary battery supplying power to the main memory is insufficient during the period when the data associated with the execution program is stored in the main memory, the data associated with the execution program can be protected. Attached Figure Description

[0013] Figure 1 This is a block diagram of a power supply system including the electronic control device according to the first embodiment of the present invention.

[0014] Figure 2This is a diagram showing the program execution state of the electronic control device according to the first embodiment.

[0015] Figure 3 This is a diagram showing the standby state of the electronic control device according to the first embodiment.

[0016] Figure 4 This is a diagram showing the stopped state of the electronic control device according to the first embodiment.

[0017] Figure 5 This is a flowchart illustrating an example of the control process of an electronic control method executed by an electronic control device according to the first embodiment.

[0018] Figure 6 This is a graph showing the shift in voltage reduction of the auxiliary battery in this embodiment.

[0019] Figure 7 This is a block diagram of a power supply system including the electronic control device according to the second embodiment of the present invention.

[0020] Figure 8 This is a flowchart illustrating an example of the control process of an electronic control method executed by an electronic control device according to the second embodiment. Detailed Implementation

[0021] The electronic control device and electronic control method according to embodiments of the present invention will now be described with reference to the accompanying drawings.

[0022] <<First Implementation Method>>

[0023] Figure 1 This is a block diagram of a power supply system equipped with the electronic control device according to the first embodiment of the present invention. The electronic control device 10 is an electronic control unit (ECU) mounted in a vehicle, and is a controller that controls the vehicle's load. The vehicle is equipped with multiple electronic control devices 10, each of which controls various functions of the vehicle, such as the drive system, auxiliary equipment systems like lights, navigation devices, and display control for the display. The vehicle is equipped with an in-vehicle network such as CAN (Controller Area Network) that allows communication between multiple electronic control devices 10. Figure 1 The diagram shows an electronic control device 10, which is interconnected with other electronic control devices (not shown) via CAN bus 5 to transmit information. Figure 1 The power system 100 shown is a system that supplies power to the electronic control device 10 from the vehicle battery 1.

[0024] like Figure 1 As shown, the power system 100 includes a battery 1, a power cord 2, a switch 3, an ACC line 4, and an electronic control unit 10. The battery 1 is the vehicle's battery and serves as the power source for operating the electronic control unit 10. The battery 1 may be, for example, a 12V battery that supplies power to auxiliary equipment, or a high-capacity battery used in electric vehicles or hybrid vehicles. The battery 1 is located external to each electronic control unit 10 and is connected to multiple electronic control units 10, supplying power to each of them. Specifically, the battery 1 supplies power to the components of the electronic control unit 10, namely the control unit 20, the main memory 30, the non-volatile memory 40, and the auxiliary battery 50. In this embodiment, when the ACC (accessory) is on, the battery 1 supplies power to the components of the electronic control unit 10.

[0025] Power line 2 is a power line that electrically connects battery 1 to electronic control device 10. Power line 2 becomes a branch line at branch point 6, branching into line 21 connecting branch point 6 to control unit 20 and line 22 connecting branch point 6 to auxiliary battery 50. Power line 2 is connected to main memory 30 and non-volatile memory 40 via control unit 20.

[0026] Switch 3 is, for example, a semiconductor component composed of a semiconductor switch, such as a FET or other transistor. Switch 3 is connected to power line 2 between battery 1 and electronic control device 10. More specifically, switch 3 is connected to power line 2 between battery 1 and branch point 6. Switch 3 has the function of switching the electrical conduction and disconnection between battery 1 and electronic control device 10.

[0027] Switch 3 is connected to ACC line 4. ACC line 4 outputs a signal to switch 3 based on whether ACC is on or off. When ACC power is on, ACC line 4 outputs an ACC on signal to switch 3 indicating that ACC is on. When ACC power is off, ACC line 4 outputs an ACC off signal to switch 3 indicating that ACC is off. Switch 3 physically switches the current flowing through power line 2 based on whether ACC line 4 is on or off. When ACC is on, switch 3 switches the current flowing through power line 2 to on. When ACC line 4 is off, switch 3 switches the current flowing through power line 2 to off. Thus, when ACC is off, switch 3 cuts off the power supply from the vehicle's battery 1 to the components of the electronic control unit 10.

[0028] The electronic control unit 10 includes a control unit 20, a main memory 30, a non-volatile memory 40, and an auxiliary battery 50. The control unit 20 includes a CPU that executes programs to implement various functions of the electronic control unit 10. For example, the control unit 20 is a System on a Chip (SOC) or a personal computer. The programs include, for example, programs for implementing functions related to vehicle control, programs for implementing voltage monitoring functions for monitoring the voltage of the auxiliary battery 50, and programs for implementing data writing functions for writing data associated with executing programs stored in the main memory 30 to the non-volatile memory 40. Each program is stored in the non-volatile memory 40. During normal program execution, the control unit 20 expands and executes the programs in the main memory 30, thereby implementing the functions of the electronic control unit 10.

[0029] In this embodiment, the electronic control device 10 has multiple states. The states of each component included in the electronic control device 10, such as operating state and power supply state, differ according to each state of the electronic control device 10. The states of the electronic control device 10 include program execution state, standby state, and stop state. When the ACC is turned on, the electronic control device 10 enters the program execution state. In the program execution state, the program is expanded from the non-volatile memory 40 to the main memory 30, and the device is in a state where the program is being executed by the control unit 20 or is capable of executing the program.

[0030] Figure 2 This is a diagram illustrating the program execution state of the electronic control device according to the first embodiment. Figure 2The diagram illustrates the operational and power supply states of each component during program execution. In program execution mode, the control unit 20, main memory 30, and non-volatile memory 40 are energized (powered state). For example, when ACC is engaged, power is supplied to each component of the electronic control unit 10 from battery 1, thereby energizing the control unit 20, main memory 30, and non-volatile memory 40. The control unit 20 loads a program from the non-volatile memory 40 into the main memory 30, and executes the program when initialization is complete. During the program execution state of the electronic control unit 10, object data is stored in the main memory 30 to maintain a state where the program can be executed. Object data is data associated with the program executed by the control unit 20. For example, object data includes the OS executed by the control unit 20, application programs, and various data required for processing by the control unit 20. The various data required for processing by the control unit 20 include data associated with vehicle functions such as vehicle driving control and user profile data. Furthermore, as will be described later, even when the ACC is disconnected, the control unit 20, main memory 30, and non-volatile memory 40 are kept powered by the auxiliary battery 50 continuing to supply power to the components of the electronic control device 10. Thus, the electronic control device 10 maintains its program execution state.

[0031] Furthermore, when the ACC is disconnected, i.e., when the power supply to the electronic control device 10 switches from battery 1 to auxiliary battery 50, the control unit 20 monitors the status of the auxiliary battery 50. Specifically, the control unit 20 acquires voltage information of the auxiliary battery 50 at regular intervals. The voltage information is obtained by measuring the voltage of the auxiliary battery 50.

[0032] The control unit 20 changes the state of the electronic control device 10 based on the voltage of the auxiliary battery 50. Specifically, the control unit 20 determines whether the voltage of the auxiliary battery 50 has fallen below a first predetermined voltage based on voltage information. The first predetermined voltage is a voltage higher than the voltage required to write at least a portion of the object data stored in the main memory 30 into the non-volatile memory 40. When the voltage of the auxiliary battery 50 is not lower than the first predetermined voltage, that is, when the voltage of the auxiliary battery 50 is higher than the first predetermined voltage, the control unit 20 maintains the program execution state of the electronic control device 10. That is, the control unit 20 maintains the energized state of the control unit 20, the main memory 30, and the non-volatile memory 40 by continuing the power supply from the auxiliary battery 50 to each component of the electronic control device 10. Thus, in the program execution state, the object data is stored in the main memory 30 in a state where the program can be executed. In addition, the control unit 20 continues to execute the program. At this time, if the electronic control device 10 has a display or the like, since the display or the like can be immediately powered on, the power to the display can also be turned off.

[0033] When the voltage of the auxiliary battery 50 drops below the first predetermined voltage, the control unit 20 changes the electronic control device 10 from the program execution state to the standby state. Figure 3 This diagram illustrates the standby state of the electronic control device 10 according to this embodiment. Figure 3 The diagram shows the operating state and power supply state of each component in standby mode. Standby mode is a state in which the electronic control device 10 consumes less power compared to the program execution state. When the electronic control device 10 is in standby mode, the control unit 20 is in a dormant state. In the dormant state, the control unit 20 stops the program counter. As a result, the control unit 20 suppresses the power consumption required for operation, thus becoming a power-saving state compared to the program execution state, which does not require power supply from the auxiliary battery 50.

[0034] Furthermore, when the electronic control device 10 is in standby mode, the main memory 30 maintains a program execution state. In program execution mode, the control unit 20 maintains the state where object data is stored in the main memory 30 by continuing the power supply from the auxiliary battery 50 to the main memory 30, thus enabling program execution. That is, the main memory 30 remains powered on, maintaining the state when the program is executed. Additionally, when the electronic control device 10 is in standby mode, the non-volatile memory 40 becomes in a stopped state. The stopped state is the state where the power supply to the non-volatile memory 40 is cut off (power-off state). Furthermore, in standby mode, it is not limited to only the main memory 30 remaining powered on and only the non-volatile memory 40 being in a stopped state; other components besides the control unit 20 and the main memory 30 may also be in a stopped state.

[0035] Standby state is a state known as "Suspend to RAM". That is, when the voltage of the auxiliary battery 50 drops below a first predetermined voltage, the control unit 20 maintains the state where object data is stored in the main memory 30, thus suppressing power consumption in the control unit 20 and the non-volatile memory 40, ensuring program execution. In standby state, object data is stored in the main memory 30, so when transitioning from standby state to program execution state, it is not necessary to reload the program from the non-volatile memory 40 to the main memory 30 for initialization, allowing for rapid program execution. Furthermore, during the transition to standby state, the control unit 20 can also switch from supplying power only to the main memory 30 from the auxiliary battery 50, stopping power supply to the control unit 20 and the non-volatile memory 40, thus entering a stopped state. As will be described later, when the electronic control device 10 enters standby mode, the control unit 20, after writing at least a portion of the object data stored in the main memory 30 to the non-volatile memory 40, maintains the state in which the object data is stored in the main memory 30 in a state capable of executing programs by continuing the power supply from the auxiliary battery 50 to the main memory 30. Furthermore, in this embodiment, when the voltage of the auxiliary battery drops below a first predetermined voltage, the writing of object data to the non-volatile memory 40 and the transition to standby mode are performed, but this is not limited to this; it is also possible to perform only the writing of object data to the non-volatile memory 40. In this case, the transition to standby mode is performed separately based on the decrease in the voltage of the auxiliary battery.

[0036] If the voltage of the auxiliary battery 50 falls below a second predetermined voltage, the control unit 20 changes the electronic control device 10 from a standby state to a stop state. The second predetermined voltage is a voltage lower than the first predetermined voltage. After the voltage of the auxiliary battery 50 falls below the first predetermined voltage, the control unit 20 continues to monitor the voltage of the auxiliary battery 50 and determines whether the voltage of the auxiliary battery 50 has fallen below the second predetermined voltage. If the control unit 20 determines that the voltage of the auxiliary battery 50 has fallen below the second predetermined voltage, it causes the device to switch to a stop state. Figure 4 This is a diagram showing the stopped state of the electronic control device 10 according to the first embodiment. Figure 4The diagram illustrates the operating state and power supply state of each component in the stop state. The stop state is a state where the power consumption of the electronic control device 10 is lower than that of the standby state. In the stop state, the power supply to the control unit 20, the main memory 30, and the non-volatile memory 40 is cut off (power-off state). The control unit 20 causes the electronic control device 10 to enter the stop state by stopping the power supply from the auxiliary battery 50 to each component of the electronic control device 10, including the main memory 30. As described later, when the electronic control device 10 enters the stop state, the control unit 20 writes the remaining portion of the object data stored in the main memory 30 to the non-volatile memory 40, and then causes the electronic control device 10 to enter the stop state. In the stop state, components other than the control unit 20, the main memory 30, and the non-volatile memory 40 can also be set to the stop state.

[0037] Here, the relationship between the first specified voltage and the second specified voltage will be explained. The second specified voltage is the voltage required to write at least a portion of the object data stored in the main memory 30 into the non-volatile memory 40. For example, the second specified voltage is a voltage higher than the limit value of the voltage required to write the object data into the non-volatile memory 40. In addition, the first specified voltage is a voltage higher than the second specified voltage. Specifically, the first specified voltage is set such that the period taken for the voltage of the auxiliary battery 50 to decrease from the first specified voltage to the second specified voltage is a predetermined specified period. The specified period is, for example, two weeks. More specifically, the period taken for the voltage of the auxiliary battery 50 to decrease from the first specified voltage to the second specified voltage is the period taken for the voltage of the auxiliary battery 50 to decrease from the first specified voltage to the second specified voltage due to the power consumption of the control unit 20 and the main memory 30 in the standby state. This is because, in the standby state, the power consumption of the control unit 20 and the main memory 30 is very low and can be maintained for a long time. Most drivers will start the vehicle engine once every two weeks, so the period is set with the possibility of the driver starting the engine in mind. Therefore, when the driver starts the engine, the electronic control unit 10 can start up quickly from the standby state, thus preventing trouble for the driver.

[0038] Furthermore, in this embodiment, the first predetermined voltage and / or the second predetermined voltage can also be set according to the amount of object data stored in the main memory 30. The larger the amount of object data, the larger the first predetermined voltage and / or the second predetermined voltage are set.

[0039] As described above, in this embodiment, when the ACC is disconnected, the control unit 20 changes the state of the electronic control device 10 according to the voltage of the auxiliary battery 50. This suppresses power consumption in the electronic control device 10. Specifically, during the program execution state, the power consumption in the electronic control device 10 is several hundred mA. When the state of the electronic control device 10 changes to a standby state, the power consumption becomes only a few to tens of mA, significantly suppressing power consumption. Furthermore, when the execution state of the electronic control device 10 changes to a stop state, the power consumption becomes only 0.1 mA, further suppressing power consumption.

[0040] Furthermore, in this embodiment, the control unit 20 performs a data write process to write object data stored in the main memory 30 to the non-volatile memory 40 based on the voltage of the auxiliary battery 50. The data write process is used to save the object data to the non-volatile memory 40 to protect the object data. If the voltage of the auxiliary battery 50 is higher than a first predetermined voltage, the control unit 20 does not perform the data write process and maintains the state of storing the object data in the main memory 30.

[0041] When the voltage of the auxiliary battery 50 falls below a first predetermined voltage, the control unit 20 writes at least a portion of the object data into the non-volatile memory 40. This data writing process is also called the first data writing process. The amount of object data written into the non-volatile memory 40 in the first data writing process can be a predetermined amount set in advance. In the first data writing process, the control unit 20 can write at least a portion of the object data into the non-volatile memory 40 in descending order of importance. Furthermore, the control unit 20 writes object data with an importance of a predetermined threshold or higher into the non-volatile memory 40 prior to object data with an importance lower than the predetermined threshold. The importance is predetermined for each category of the object data. For example, the importance of object data related to vehicle operation is set higher than the importance of object data related to functions other than vehicle operation. Additionally, the importance of object data related to vehicle safety is set higher than the importance of object data other than vehicle safety. Furthermore, the control unit 20 may also prioritize writing user-related profile data from the object data into the non-volatile memory 40. Profile data includes the user's own information, information about other users owned by the user, etc. Furthermore, in this embodiment, after the first data write process, the control unit 20 maintains the state in which the object data is stored in the main memory 30 in a state where the program can be executed, and sets the control unit 20 and the non-volatile memory 40 to a state where power consumption is suppressed. As a result, the electronic control device 10 switches to a standby state.

[0042] Furthermore, when the voltage of the auxiliary battery 50 drops below a second predetermined voltage, the control unit 20 performs a data write process to write the remaining object data stored in the main memory 30 to the non-volatile memory 40. This data write process is also called the second data write process. In the second data write process, the control unit 20 writes object data that was not written to the non-volatile memory 40 in the first data write process to the non-volatile memory 40. For example, the control unit 20 writes object data with low importance to the non-volatile memory 40. More specifically, the control unit 20 may also write object data with an importance of a predetermined threshold or higher to the non-volatile memory 40 in the first data write process, and write object data with an importance of less than the predetermined threshold to the non-volatile memory 40 in the second data write process. In addition, in this embodiment, after the second data write process, the control unit 20 stops supplying power from the auxiliary battery 50 to the main memory 30. As a result, the electronic control device 10 enters a stop state.

[0043] Main memory 30 is a memory that temporarily stores data associated with the executed program. For example, main memory 30 temporarily stores the OS executed by control unit 20, application programs, and various data required for processing by control unit 20. Main memory 30 is, for example, RAM. In main memory 30, when program execution begins, the program to be executed is loaded from non-volatile memory 40 and executed after initialization. Non-volatile memory 40 stores the OS and application programs executed by control unit 20. Non-volatile memory 40 is, for example, flash memory (storage device). Non-volatile memory 40 is not limited to flash memory; it can be any memory that retains its storage even without a power supply.

[0044] The auxiliary battery 50 is a battery different from the battery 1, and is built into each of the electronic control devices 10. The auxiliary battery 50 is an auxiliary battery used to supply power to the components of the electronic control devices 10 when the power supply from the battery 1 is cut off. For example, in this embodiment, power is supplied from the battery 1 when the ACC is on, but the power supply from the battery 1 is cut off when the ACC is off. Therefore, when the ACC is off, the auxiliary battery 50 supplies power to the components of the electronic control devices 10. This prevents the vehicle's battery 1 from being depleted. The objects powered by the auxiliary battery 50 include the control unit 20, the main memory 30, and the non-volatile memory 40.

[0045] Next, use Figure 5 Here is an example illustrating the control process of the electronic control method involved in this embodiment. Figure 5This is a flowchart illustrating an example of the control process of the electronic control method executed by the electronic control device 10 according to the first embodiment. In this embodiment, when the ACC is disconnected and the power supply to the electronic control device 10 is switched from the vehicle's battery 1 to the auxiliary battery 50, the control unit 20 starts the process from step S101.

[0046] In step S101, the control unit 20 obtains voltage information of the auxiliary battery 50 from the auxiliary battery 50. In step S102, based on the voltage information obtained in step S101, the control unit 20 determines whether the voltage of the auxiliary battery 50 has fallen below a first predetermined voltage. If it is determined that the voltage of the auxiliary battery 50 has fallen below the first predetermined voltage, the control unit 20 proceeds to step S103. If it is determined that the voltage of the auxiliary battery 50 is not below the first predetermined voltage, that is, the voltage of the auxiliary battery 50 is higher than the first predetermined voltage, the control unit 20 proceeds to step S104.

[0047] In step S103, the control unit 20 writes the object data stored in the main memory 30 into the non-volatile memory 40. The object data is data associated with the program executed by the control unit 20. It can be all or a portion of the object data. Furthermore, after writing the object data into the non-volatile memory 40 in step S103, the control unit 20 may switch the electronic control device 10 from the program execution state to a standby state. In the standby state, the object data is stored in the main memory 30 in a state where the program can be executed. The control unit 20 maintains the object data stored in the main memory 30 in a state where the program can be executed by continuing the power supply from the auxiliary battery 50 to the main memory 30.

[0048] In step S104, the control unit 20 maintains the program execution state of the electronic control device 10. In the program execution state, power is supplied to the control unit 20, main memory 30, and non-volatile memory 40 from the auxiliary battery 50. The control unit 20 and main memory 30 maintain the program execution state. After processing in step S104, the control unit 20 returns to step S101, and then repeats the process. That is, in this embodiment, the control unit 20 continuously monitors the voltage of the auxiliary battery 50 at regular intervals, and maintains the program execution state of the electronic control device 10 while the voltage of the auxiliary battery 50 is higher than a first predetermined voltage. Then, when the voltage of the auxiliary battery 50 decreases to below the first predetermined voltage, the control unit 20 proceeds to step S103.

[0049] As described above, in the electronic control device and electronic control method according to this embodiment, the electronic control device includes a control unit, a main memory, a non-volatile memory, and an auxiliary battery for supplying power to the main memory. The control unit acquires voltage information of the auxiliary battery, and when the voltage of the auxiliary battery falls below a first predetermined voltage, the control unit writes at least a portion of the object data stored in the main memory that is associated with the program executed by the control unit into the non-volatile memory. Therefore, even if the voltage of the auxiliary battery supplying power to the main memory becomes insufficient while maintaining the state where the data associated with the executed program is stored in the main memory, the data associated with the executed program can be protected.

[0050] Furthermore, in the electronic control device and electronic control method according to this embodiment, the first predetermined voltage is a voltage higher than the voltage required to write at least a portion of the target data into the non-volatile memory. Therefore, data associated with the executed program can be stored in the non-volatile memory when the voltage of the auxiliary battery is higher than the voltage required to write to the non-volatile memory.

[0051] Furthermore, in the electronic control device and electronic control method according to this embodiment, when the voltage of the auxiliary battery is higher than a first predetermined voltage, the control unit maintains the state in which the object data is stored in the main memory by continuing the power supply from the auxiliary battery to the main memory. Thus, while the voltage of the auxiliary battery is sufficiently high, the main memory can continuously store data associated with the executed program.

[0052] Furthermore, in the electronic control device and electronic control method according to this embodiment, when the voltage of the auxiliary battery falls below a first predetermined voltage, the control unit, after writing at least a portion of the target data into the non-volatile memory, maintains the state in which the target data is stored in the main memory in a state capable of executing the program by continuing the power supply from the auxiliary battery to the main memory. Therefore, even if the voltage of the auxiliary battery becomes insufficient during the period when the target data is maintained in the main memory in a state capable of executing the program, data associated with executing the program can be protected.

[0053] Furthermore, in the electronic control device and electronic control method according to this embodiment, when the voltage of the auxiliary battery drops to a second predetermined voltage, which is lower than a first predetermined voltage, the control unit writes the remaining object data stored in the main memory to a non-volatile memory and stops the power supply from the auxiliary battery to the main memory. Therefore, even when the voltage of the auxiliary battery decreases, data associated with the executed program can be protected.

[0054] Furthermore, in the electronic control device and electronic control method according to this embodiment, the control unit writes at least a portion of the object data into a non-volatile memory in descending order of importance. This allows for the protection of important data associated with the executed program.

[0055] Furthermore, in the electronic control device and electronic control method according to this embodiment, the control unit writes the user-related profile data from the object data into a non-volatile memory. This protects the user's profile data from the data associated with the executable program.

[0056] <<Second Implementation Method>>

[0057] In the first embodiment, the processing up to the point where the electronic control device 10 changes to a stop state has been described, but the present invention is not limited to the embodiment described above. The electronic control device 10 may also be configured to perform processing after it changes to a stop state. For example, the control unit 20 may also have a function to perform processing for protecting target data when the electronic control device 10 is in a stop state and the ACC is turned on.

[0058] When the electronic control unit 10 is switched to the off state and the ACC is switched on, firstly, an on signal indicating that the ACC is switched on is output from the ACC line 4 to the switch 3. Switch 3 initiates the power supply from the vehicle's battery 1 to the various components of the electronic control unit 10 (control unit 20, main memory 30, non-volatile memory 40, and auxiliary battery 50), thereby supplying power to the control unit 20, main memory 30, and non-volatile memory 40, and charging the auxiliary battery 50. Normally, the engine power is used to adequately power the battery 1 and auxiliary battery 50 via the alternator. However, in some cases, the engine may not start, causing the switched ACC to disconnect again. In this situation, the electronic control unit 10 is in the off state. Since the voltage of the auxiliary battery 50 is below the second predetermined voltage, it remains below the second predetermined voltage during the period from when the ACC is switched on until it is switched off again, as sufficient power cannot be supplied to the auxiliary battery 50.

[0059] Therefore, when the ACC is disconnected and the control unit 20 begins monitoring the voltage of the auxiliary battery 50, since the condition that the voltage of the auxiliary battery 50 is below the second predetermined voltage is met, the control unit 20 immediately writes the object data to the non-volatile memory 40 and transitions to the stop state. However, at this time, the voltage of the auxiliary battery 50 is below the voltage required for the object data to be stored in the non-volatile memory 40. Therefore, sometimes the required power supply from the auxiliary battery 50 cannot be obtained midway through writing the object data to the non-volatile memory 40, thus the writing of the object data to the non-volatile memory 40 is not performed normally. Therefore, the object data may be corrupted.

[0060] Here, use Figure 6 This section explains the relationship between the voltage drop of the auxiliary battery and data writing processing. Figure 6 This is a graph showing the shift in voltage reduction of the auxiliary battery in this embodiment. Figure 6 The diagram shows the voltage change of the auxiliary battery 50 from time T1 when the ACC is disconnected. The auxiliary battery 50 continues to supply power to the electronic control unit 10 after the ACC is disconnected, and its voltage decreases accordingly. When the voltage of the auxiliary battery 50 drops to a second predetermined voltage V2, the control unit 20 switches the electronic control unit 10 to a stop state from time T2 when the voltage of the auxiliary battery 50 falls below the second predetermined voltage V2. Then, when the ACC is turned on, the electronic control unit 10 starts. Sometimes, the ACC is disconnected again immediately after the electronic control unit 10 starts. When the ACC is disconnected, power supply to the electronic control unit 10 from the auxiliary battery 50 begins. The control unit 20 also begins monitoring the voltage of the auxiliary battery 50, but since the voltage of the auxiliary battery 50 is still below the second predetermined voltage, the control unit 20 immediately begins data writing processing to write target data to the non-volatile memory 40 in order to switch the electronic control unit 10 to a stop state again.

[0061] exist Figure 6 In the example, data writing processing begins at time point T3, and power is cut off at time point T4, the end of the data writing process. The power cut-off ends at time point T5. During this time, due to the power consumption caused by the data writing process, the voltage of the auxiliary battery 50 begins to decrease from time point T3, when the data writing process begins writing object data to the non-volatile memory 40. During the period until time point T4, the voltage of the auxiliary battery 50 is lower than the voltage limit required for the data writing process. When the voltage of the auxiliary battery 50 is lower than the required voltage limit, there is a possibility that the data writing process will not execute normally, resulting in data corruption. In this embodiment, to prevent such a situation, the control unit 20 controls the switch 3 to supply power from the vehicle's battery 1 instead of the auxiliary battery 50.

[0062] use Figure 7 An example of power supply switching control performed by the control unit 20 will be explained. Figure 7 This is a block diagram of a power supply system including the electronic control device according to the second embodiment of the present invention. In the second embodiment, the structure is the same as that of the first embodiment, except for the structure shown below. In the following description, descriptions of structures and control processes identical to those in the first embodiment are omitted, and the omitted descriptions are appropriately referenced from the descriptions of the first embodiment. The difference between the second embodiment and the first embodiment is that it includes a communication line 7 connecting the control unit 20 and the switch 3.

[0063] In the second embodiment, the control unit 20 determines whether the voltage of the auxiliary battery 50 has fallen below a second predetermined voltage based on voltage information. If the voltage of the auxiliary battery 50 falls below the second predetermined voltage, the control unit 20 supplies power from the vehicle's battery 1 to the auxiliary battery 50. That is, in this embodiment, when the ACC is off, the control unit 20 continuously monitors the voltage of the auxiliary battery 50. After the voltage of the auxiliary battery 50 falls below a first predetermined voltage and the electronic control device 10 switches to standby mode, the control unit 20 continues to monitor the voltage decrease of the auxiliary battery 50 and determines whether the voltage of the auxiliary battery 50 has fallen below the second predetermined voltage. Furthermore, if the voltage of the auxiliary battery 50 falls below the second predetermined voltage, the control unit 20 controls the switch 3 to supply power from the vehicle's battery 1 to the auxiliary battery 50. The power supply from the vehicle's battery 1 can also be configured to supply power not only to the auxiliary battery 50, but also to the control unit 20, the main memory 30, and the non-volatile memory 40. Alternatively, the auxiliary battery 50, which receives power from the vehicle's battery 1, can be configured to supply power to the control unit 20, the main memory 30, and the non-volatile memory 40.

[0064] Here, the power supply under the control of switch 3 will be explained. When the control unit 20 determines that the voltage of the auxiliary battery 50 has fallen below the second predetermined voltage, it outputs an on signal to switch 3 via communication line 7, instructing switch 3 to turn on. If at least one of the signal output from ACC line 4 and the signal output from control unit 20 is an on signal, switch 3 switches the current flowing in power line 2 to on. If both the signal output from ACC line 4 and the signal output from control unit 20 are off signals, switch 3 switches the current flowing in power line 2 to off. Thus, when the voltage of the auxiliary battery 50 falls below the second predetermined voltage, control unit 20 switches the power supply to the electronic control device 10 from the auxiliary battery 50 to the vehicle's battery 1. As described above, during the period after ACC is disconnected and the object data is stored in the main memory 30 in a state where the program can be executed, when the voltage of the auxiliary battery 50 falls below the second predetermined voltage, control unit 20 controls switch 3 to supply power from vehicle battery 1 to auxiliary battery 50.

[0065] When the voltage of the auxiliary battery 50 exceeds the second predetermined voltage due to the power supply from the vehicle's battery 1, the control unit 20 writes the target data into the non-volatile memory 40 and puts the electronic control device 10 into a stop state. Thus, the power required to write the target data into the non-volatile memory 40 can be supplied from the auxiliary battery 50, and therefore the target data can be written into the non-volatile memory 40 normally.

[0066] Next, use Figure 8 Here is an example of the control process of the electronic control method according to the second embodiment of the present invention. Figure 8 This is a flowchart illustrating an example of the control process of the electronic control method executed by the electronic control device 10 according to the second embodiment. In this embodiment, when the voltage of the auxiliary battery 50 drops below a first predetermined voltage when the ACC is disconnected and the execution state of the electronic control device 10 changes to a standby state, the control unit 20 starts the process from step S201.

[0067] In step S201, the control unit 20 obtains voltage information of the auxiliary battery 50 from the auxiliary battery 50. In step S202, based on the voltage information obtained in step S201, the control unit 20 determines whether the voltage of the auxiliary battery 50 has fallen below a second predetermined voltage. If it is determined that the voltage of the auxiliary battery 50 has fallen below the second predetermined voltage, the control unit 20 proceeds to step S203. If it is determined that the voltage of the auxiliary battery 50 is not below the second predetermined voltage, that is, the voltage of the auxiliary battery 50 is higher than the second predetermined voltage, the control unit 20 proceeds to step S204.

[0068] In step S203, the control unit 20 switches the power supply to the electronic control device 10 from the auxiliary battery 50 to the vehicle's battery 1. Specifically, the control unit 20 outputs an on signal to the switch 3 via the communication line 7, instructing the switch 3 to turn on. When the on signal is input from the control unit 20, the switch 3 switches the current flowing in the power line 2 to on, thereby supplying power from the vehicle's battery 1 to the electronic control device 10. In step S204, the control unit 20 maintains the electronic control device 10 in a standby state. After processing in step S204, the control unit 20 returns to step S201 and then repeats the process. That is, in this embodiment, the control unit 20 continuously monitors the voltage of the auxiliary battery 50 at a certain period, and maintains the standby state of the electronic control device 10 while the voltage of the auxiliary battery 50 is higher than a second predetermined voltage. Then, when the voltage of the auxiliary battery 50 decreases to below the second predetermined voltage, the control unit 20 proceeds to step S203.

[0069] As described above, in the electronic control device and electronic control method according to this embodiment, when the voltage of the auxiliary battery drops to a second predetermined voltage, which is lower than a first predetermined voltage, the control unit supplies power from the vehicle's battery to the main memory. Therefore, even when the voltage of the auxiliary battery decreases, the writing of data to the non-volatile memory and the power-off can be performed normally.

[0070] Furthermore, in the electronic control device and electronic control method according to this embodiment, when the vehicle's ACC is disconnected, during the period when the auxiliary battery supplies power to the main memory to maintain the state in which the target data is stored in the main memory so that the program can be executed, if the voltage of the auxiliary battery drops to a second predetermined voltage lower than a first predetermined voltage, the control unit supplies power from the vehicle's battery to the auxiliary battery. Therefore, while maintaining the state in which the main memory stores data associated with the executed program, even when the voltage of the auxiliary battery decreases, the writing of data to the non-volatile memory and the power-off can be performed normally.

[0071] Furthermore, the embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit the present invention. Therefore, the elements disclosed in the above embodiments are intended to include all design modifications and equivalents that fall within the scope of the present invention.

[0072] Explanation of reference numerals in the attached figures

[0073] 1…battery

[0074] 2…Power cord

[0075] 3…Switch

[0076] 4…ACC line

[0077] 10… Electronic control device

[0078] 20…Control Department

[0079] 30…Main Memory

[0080] 40…Non-volatile memory

[0081] 50… Auxiliary Battery

Claims

1. An electronic control device comprising a control unit, a main memory, a non-volatile memory, and an auxiliary battery for supplying power to the main memory, wherein, The control unit acquires the voltage information of the auxiliary battery. When the voltage of the auxiliary battery drops below a first predetermined voltage, the control unit writes at least a portion of the object data stored in the main memory and associated with the program executed by the control unit into the non-volatile memory.

2. The electronic control device according to claim 1, wherein, The first specified voltage is a voltage higher than the voltage required to write at least a portion of the object data into the non-volatile memory.

3. The electronic control device according to claim 1 or 2, wherein, When the voltage of the auxiliary battery is higher than the first predetermined voltage, the control unit maintains the state in which the object data is stored in the main memory by continuing the power supply from the auxiliary battery to the main memory.

4. The electronic control device according to any one of claims 1 to 3, wherein, When the voltage of the auxiliary battery drops below the first predetermined voltage, the control unit, after writing at least a portion of the object data into the non-volatile memory, maintains the state in which the object data is stored in the main memory in a state where the program can be executed by continuing the power supply from the auxiliary battery to the main memory.

5. The electronic control device according to any one of claims 1 to 4, wherein, When the voltage of the auxiliary battery drops below a second predetermined voltage, which is lower than the first predetermined voltage, the control unit supplies power from the vehicle's battery to the main memory.

6. The electronic control device according to any one of claims 1 to 5, wherein, While maintaining the state in which the object data is stored in the main memory by supplying power from the auxiliary battery to the main memory in order to execute the program when the voltage of the auxiliary battery drops below a second predetermined voltage that is lower than the first predetermined voltage, the control unit supplies power from the vehicle's battery to the auxiliary battery.

7. The electronic control device according to any one of claims 1 to 4, wherein, When the voltage of the auxiliary battery drops below a second predetermined voltage that is lower than the first predetermined voltage, the control unit writes the remaining object data stored in the main memory into the non-volatile memory and stops the power supply from the auxiliary battery to the main memory.

8. The electronic control device according to any one of claims 1 to 7, wherein, The control unit writes at least a portion of the object data into the non-volatile memory in descending order of importance.

9. The electronic control device according to any one of claims 1 to 7, wherein, The control unit writes the user-associated profile data from the object data into the non-volatile memory.

10. An electronic control method executed by an electronic control device, the electronic control device comprising a control unit, a main memory, a non-volatile memory, and an auxiliary battery for supplying power to the main memory, wherein in the electronic control method, The control unit acquires the voltage information of the auxiliary battery. When the voltage of the auxiliary battery drops below a first predetermined voltage, the control unit writes at least a portion of the object data stored in the main memory and associated with the program executed by the control unit into the non-volatile memory.

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