Display device for vehicle

Abstract

To provide a display device for a vehicle capable of appropriately operating a reset circuit even when a voltage of a battery power source is lowered.SOLUTION: A display device M for a vehicle includes: a display 2 for displaying an image; and a multicore SOC 1 which allows the display 2 to display an image indicating vehicle information. The display device for a vehicle further includes: a first power source circuit 54 which supplies a first power source by stepping down a battery voltage supplied from an on-vehicle battery BAT to the first voltage; a second power source circuit 55 which steps down the first power supply source supplied from the first power source circuit 54 to a second voltage and supplies it to the display 2 and the SOC 1; and a reset circuit 4 which outputs a reset signal to the SOC 1 on the basis of a voltage output by the first power source circuit 54.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a display device for a vehicle. [Background technology]

[0002] FIG. 1 of Patent Document 1 discloses an in-vehicle device including a reset circuit (50) that outputs a reset signal to a control unit (10) based on the output of a power supply voltage of 3.3 V output from a stabilized power supply (20). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6672994 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-described in-vehicle device, if the power supply voltage drops due to deterioration of the in-vehicle battery (BAT) that supplies power to the stabilized power supply (20), the reset circuit (50) may not be able to correctly output a reset signal to the control unit (10).

[0005] In consideration of the above-mentioned problems, the present disclosure has an object to provide a vehicle display device that can properly operate a reset circuit even when the voltage of a battery power source drops. [Means for solving the problem]

[0006] The vehicle display device of the present disclosure includes: A display for displaying an image; A vehicle display device including: a first power supply circuit that steps down a battery power source supplied from an in-vehicle battery to a first voltage and supplies the first power supply; a second power supply circuit that steps down the first power supply supplied from the first power supply circuit to a second voltage and supplies the second voltage to the display and the SOC; and a reset circuit that outputs a reset signal to the SOC based on the voltage output by the first power supply circuit. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide a vehicle display device that can properly operate a reset circuit even when the voltage of a battery power source drops. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a system configuration of a display device for a vehicle. [Diagram 2] FIG. 2 is a diagram showing a power supply configuration of the display device for a vehicle. [Diagram 3] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (Configuration of vehicle display device) The vehicle display device M is an instrument that displays vehicle information to a vehicle occupant, and is mounted on an instrument panel of the vehicle.

[0010] The vehicle information includes, for example, the vehicle's running speed, engine RPM, vehicle automatic control status, warning lights, remaining fuel amount (remaining energy amount), tire pressure, route guidance, images from an in-vehicle camera, total distance traveled, elapsed time, average fuel consumption, instantaneous fuel consumption, setting data, etc. The elapsed time includes, for example, the time since the last maintenance.

[0011] The automatic vehicle control state is an operating state of an automatic driving mode in which the vehicle automatically controls the acceleration / deceleration and steering of the vehicle. The automatic driving mode includes, for example, an autopilot mode in which the vehicle travels at a constant speed while maintaining a constant distance from the vehicle ahead, an auto lane change mode in which the vehicle controls the steering and changes lanes when the driver operates the turn signal, and an auto park mode in which the vehicle moves to a location where it determines it is possible to park and parks it.

[0012] As shown in FIG. 1, the vehicle display device M includes a SOC (System On a Chip) 1, a display 2, a timer unit 3, a reset circuit 4, and a power supply circuit 5.

[0013] SOC1 is an integrated semiconductor chip in which all of the functions necessary for the operation of the vehicle display device M are implemented in a single integrated circuit chip. The function necessary for the operation of the vehicle display device M is a function for displaying vehicle information on the display 2 (instrument display function). SOC1 acquires a video signal capturing an image of the surroundings of the vehicle from an in-vehicle camera C that captures the surroundings of the vehicle, and displays the video signal on the display 2 as necessary. SOC1 also displays vehicle information acquired from an in-vehicle control unit E via an in-vehicle network N on the display 2. Details of SOC1 will be described later.

[0014] The display 2 is a device that displays images, such as a liquid crystal display, an organic EL display, etc. The display 2 inputs the video signal output by the SOC 1 and displays an image based on this video signal on the screen.

[0015] The timekeeping unit 3 is an RTC (real-time clock) IC that constantly keeps time, and transmits the kept date and time information to the SOC1 (a second processor core 11B described later). This date and time information is used, for example, to calculate the "elapsed time since the last maintenance" to inform the user of the "time for the next oil change" and the like. In order to keep time constantly, the timekeeping unit 3 operates by being constantly supplied with power from a third power supply circuit 53 (always-on power supply) described later.

[0016] The reset circuit 4 is a reset IC that outputs a reset signal to start (restart) the SOC 1. When the output voltage of a first power supply circuit 54 described later reaches a predetermined voltage (e.g., 5.0 V), the reset circuit 4 outputs a reset signal to the SOC 1 to start the SOC 1. The start-up process of the SOC 1 by the reset circuit 4 will be described later.

[0017] The power supply circuit 5 transforms the battery power of about 7 to 12 V supplied from the in-vehicle battery BAT, and supplies power to the SOC 1, the display 2, the clock unit 3, and the reset circuit 4. The power supply circuit 5 will be described in detail later.

[0018] (SOC configuration) As shown in FIG. 1, SOC1 incorporates a first processor core 11A, a second processor core 11B, a third processor core 11C, a PVT monitor unit 12, a communication unit 13, a video input unit 14, a display control unit 15, a ROM 16, a RAM 17, a 2D drawing unit 18, and a 3D drawing unit 19.

[0019] The first processor core 11A is an arithmetic unit that functions independently from the other cores.

[0020] The first processor core 11A operates by executing software for the first processor core. The software for the first processor core includes a first boot loader, an OS (Operating System), normal screen drawing software, update function software, image data for normal screen drawing, and sound data for normal screen drawing.

[0021] The first boot loader loads the first processor core software stored in the ROM 16 into the RAM 17, and enables the first processor core 11A to execute the first processor core software. The first boot loader has a function of verifying the integrity of the first processor core software during or after loading the first processor core software. The integrity verification uses digital signature technology such as ECDSA (Elliptic Curve Digital Signature Algorithm) to check whether the first processor core software has been tampered with or has any other defects.

[0022] The OS is the basic software for executing the normal screen drawing software and the update function software. For example, the Linux OS is used as the OS.

[0023] The normal screen drawing software is an application program that runs on the OS. In a normal display mode, which will be described later, the normal screen drawing software draws an image representing vehicle information in a corresponding area of ​​the RAM 17 in order to display a normal screen by 3D drawing on the display 2.

[0024] The update function software is an application program that runs on the OS and is a program for updating the software of each of the processor cores 11A, 11B, and 11C.

[0025] The image data for drawing a normal screen and the sound data for drawing a normal screen are data used by the normal screen drawing software for drawing the normal screen.

[0026] The second processor core 11B is an arithmetic unit that functions independently of the other cores. The second processor core 11B includes an internal memory 11B1. The internal memory 11B1 includes an in-core ROM and an in-core RAM. The second processor core 11B loads a program stored in the in-core ROM into the in-core RAM to start operation. The in-core RAM has a smaller capacity than the ROM 16.

[0027] The second processor core 11B is a secure processor core that decrypts and executes encrypted instruction codes (encrypted instruction codes). The second processor core 11B includes a core-specific key storage unit that stores a unique key (core-specific key). The in-core ROM of the internal memory 11B1 stores encrypted programs in a non-rewritable format. The second processor core 11B uses the core-specific key to authenticate the encrypted instruction codes of the programs stored in the in-core ROM, and then decrypts and executes them.

[0028] The second processor core 11B loads and executes second processor core software stored in the in-core ROM or ROM 16 into the in-core RAM or RAM 17. The second processor core software includes a second boot loader and communication software.

[0029] The second boot loader is a program stored in the in-core ROM, and is started with its integrity guaranteed. When started, the second boot loader verifies the integrity of the first boot loader and a third boot loader, which will be described later. The second boot loader also loads communication software from ROM 16 and verifies the integrity of the communication software. The method used for these verifications is, for example, the same as that for the first boot loader.

[0030] The communication software is a program for communicating with in-vehicle devices via the communication unit 13. The communication software acquires vehicle information, such as the vehicle's running speed and engine speed, from the in-vehicle ECU.

[0031] The third processor core 11C is an arithmetic unit that functions independently from the other cores.

[0032] The third processor core 11C operates by executing software for the third processor core, which includes a third boot loader, startup screen drawing software, startup screen drawing image data, and startup screen drawing sound data.

[0033] The third boot loader loads the software for the third processor core stored in the ROM 16 into the RAM 17, and enables the third processor core 11C to execute the software for the third processor core. The third boot loader has a function of verifying the integrity of the software for the third processor core during or after loading the software for the third processor core. This verification method is, for example, the same as that of the second boot loader.

[0034] In the startup display mode, the startup screen drawing software draws an image showing vehicle information in a corresponding area of ​​the RAM 17 in order to display a startup screen on the display 2 by 2D drawing.

[0035] In addition, the startup screen drawing software draws images representing vehicle information and warning messages in the corresponding areas of the RAM 17 in order to display an alternative screen by 2D drawing on the display 2 in the emergency display mode.

[0036] The start-up screen rendering image data and start-up screen rendering sound data are data used by the start-up screen rendering software to render the start-up screen or an alternative screen.

[0037] The PVT (Process, Voltage and Temperature) monitor unit 12 is a functional block that monitors whether the operation of each of the processor cores 11A to 11C is normal. The PVT monitor unit 12 monitors whether the power supply voltage and the operating clock supplied to each of the processor cores 11A to 11C are normal. The PVT monitor unit 12 also monitors whether the temperature of each of the processor cores 11A to 11C is within an operation guarantee range.

[0038] The communication unit 13 is a functional block that performs communication in accordance with a predetermined communication protocol. The predetermined communication protocol is, for example, CAN (Controller Area Network), LIN (Local Interconnect Network), MOST (Media Oriented Systems Transport), Ethernet, etc. The communication unit 13 communicates with the in-vehicle control unit E via the in-vehicle network N to acquire vehicle information and stores it in the RAM 17.

[0039] The video input unit 14 is a functional block that inputs a video signal of a predetermined standard. The video signal of the predetermined standard is NTSC (National Television System Committee), LVDS (Low Voltage Differential Signaling), HDMI (registered trademark) (High-Definition Multimedia Interface), etc. The video input unit 14 inputs a video signal of an image of the surroundings of the vehicle from the on-board camera C, and stores the video signal in the RAM 17.

[0040] The display control unit 15 is a functional block that outputs a video signal of a predetermined standard to the display 2 and causes an image showing vehicle information to be displayed on the display 2. The video signal of the predetermined standard is LVDS, HDMI (registered trademark), or the like.

[0041] The ROM 16 is a rewritable non-volatile memory, such as a NAND type flash memory or a NOR type flash memory.

[0042] The RAM 17 is a volatile memory, for example, a DDR SDRAM that transfers data by a DDR (Double Data Rate) method. The RAM 17 is a working memory that stores data calculated by each of the processor cores 11A to 11C and the above-mentioned vehicle information.

[0043] The 2D drawing unit 18 is a functional block that draws two-dimensional vector graphic or raster graphic images.

[0044] The 3D drawing unit 19 is a functional block that draws three-dimensional computer graphic images.

[0045] (Power supply circuit configuration) As shown in FIG. 2, the power supply circuit 5 includes a diode 51, a capacitor 52, a first power supply circuit 54, a second power supply circuit 55, and a third power supply circuit 53.

[0046] The diode 51 is a backflow prevention diode provided in a power supply path from the in-vehicle battery BAT to each of the power supply circuits 53 to 55. In other words, the diode 51 allows power to be supplied from the in-vehicle battery BAT to each of the power supply circuits 53 to 55, while blocking current flow from each of the power supply circuits 53 to 55 to the in-vehicle battery BAT.

[0047] Capacitor 52 is a capacitor for preventing momentary power interruption provided in a power supply path from in-vehicle battery BAT to each of power supply circuits 53 to 55. That is, capacitor 52 discharges electricity stored during power supply at the time of power interruption, thereby maintaining the power supply state even during the power interruption.

[0048] The first power supply circuit 54 is a stabilized power supply circuit that steps down the battery power supplied from the in-vehicle battery BAT and supplies power to the communication unit 13 and the second power supply circuit 55. For example, the first power supply circuit 54 is a series regulator or a switching power supply circuit, and steps down the battery power to a voltage of 5.0 V and supplies it. The power supply of the first power supply circuit 54 is also input to the reset circuit 4 as a signal used for reset determination.

[0049] The second power supply circuit 55 is a stabilized power supply circuit that steps down the 5V power supplied from the first power supply circuit 54 and supplies power to the display 2 and SOC1 (components of SOC1 excluding the second processor core 11B and the communication unit 13). For example, the second power supply circuit 55 is a series regulator or a switching power supply circuit, and steps down the 5V power to a voltage such as 3.3V, 1.8V, or 0.8V before supplying it.

[0050] The third power supply circuit 53 is a stabilized power supply circuit that steps down the battery power supply and supplies power to the second processor core 11B, the internal memory 11B1 (intra-core RAM), the clock unit 3, and the reset circuit 4. For example, the third power supply circuit 53 is a series regulator or a switching power supply circuit, and steps down the battery power supply to a voltage of 3.3 V or 1.8 V and supplies the power.

[0051] The third power supply circuit 53 is a constantly-on power supply that constantly supplies power, while the first power supply circuit 54 and the second power supply circuit 55 are ON / OFF power supplies that can turn on / off the power supply. The power supply by the first power supply circuit 54 is turned on / off by the second processor core 11B. Moreover, the power supply by the second power supply circuit 55 is turned on / off in conjunction with the ON / OFF of the first power supply circuit 54 that supplies power to the second power supply circuit 55.

[0052] (Power saving mode) When the vehicle driving function is terminated, the vehicular display device M transitions to a power saving mode until the vehicle driving function is started again. The switching of the power saving mode is controlled by the second processor core 11B outputting a control signal S to the first power supply circuit 54.

[0053] The second processor core 11B determines whether to start / stop the vehicle's driving function based on the state of the start switch included in the vehicle information acquired from the in-vehicle control unit E via the in-vehicle network N. The start switch is an ignition switch (ignition key) in the case of an engine vehicle, and a power switch in the case of an electric vehicle.

[0054] When the second processor core 11B determines that the vehicle driving function has ended, it stops the power output of the first power supply circuit 54 (including the second power supply circuit 55). As a result, the vehicular display device M transitions to a power saving mode.

[0055] Furthermore, when the second processor core 11B determines that the vehicle's driving function is started, it starts the power output of the first power supply circuit 54 (including the second power supply circuit 55). As a result, the vehicular display device M transitions from the power saving mode to the normal operation mode.

[0056] In the power saving mode, power is not supplied to components other than those powered by the third power supply circuit 53 (the second processor core 11B, the internal memory 11B1, the clock unit 3, and the reset circuit 4), resulting in reduced power consumption.

[0057] (SOC startup process) When starting the running function of the vehicle, the reset circuit 4 activates the SOC 1. The reset circuit 4 monitors the output voltage of the first power supply circuit 54, and when the output voltage of the first power supply circuit 54 reaches a predetermined voltage (e.g., 5V) in response to the start of power output from the first power supply circuit 54 by the second processor core 11B, the reset circuit 4 outputs a reset signal to the SOC 1 to activate the SOC 1.

[0058] According to this startup process of SOC1, the reset circuit 4 is operated based on the output voltage of the first power supply circuit 54, which has a higher output voltage than the second power supply circuit 55, so that the reset circuit 4 can be operated appropriately to start up SOC1 even when the voltage of the battery power source drops.

[0059] (Data evacuation process) When the vehicle display device M enters the power saving mode, the power supply to the RAM 17 is cut off, and all data stored in the RAM 17 is lost. Among the data stored in the RAM 17, there is vehicle information that needs to be continuously stored (hereinafter, appropriately referred to as data D to be saved), and this vehicle information is saved to another memory before the power supply to the RAM 17 is cut off. Examples of the data D to be saved include total mileage (ODO), elapsed time (e.g., time elapsed since the last maintenance), fuel efficiency, electricity efficiency, and display screen parameters (e.g., screen setting information, display screen information at the end of driving).

[0060] Conventionally, such data evacuation processing has been performed by writing the to-be-saved data D on the RAM 17 to the ROM 16. However, if the number of writes to the ROM 16 due to data evacuation exceeds the guaranteed number of writes to the ROM 16, the possibility of data not being stored correctly increases, so there has been a demand to reduce the number of writes in data evacuation.

[0061] 3, before switching to the power saving mode, the second processor core 11B of SOC1 performs a data evacuation process in which the data D to be saved on the RAM 17 is divided and stored in the in-core RAM of the internal memory 11B1 and the ROM 16. In particular, of the data D to be saved, the highly updated data DH is saved to the in-core RAM of the internal memory 11B1, and the less updated data DL is saved to the ROM 16. This data evacuation process can reduce the number of times the data D to be saved is written to the ROM 16, compared to saving all of the data D to be saved to the ROM 16.

[0062] For example, if the data to be saved D is the total distance traveled, the data in the higher digits (e.g., digits of 1 km or more) of the total distance traveled is set as low update frequency data DL, and the data in the lower digits (digits less than 1 km) is set as high update frequency data DH.

[0063] Furthermore, when the to-be-saved data D is elapsed time, the month data, day data, and minute data of the elapsed time are set as low-update-frequency data DL, and the second data are set as high-update-frequency data DH.

[0064] In addition, when the data D to be saved is fuel efficiency or electricity efficiency, the data in the higher digits (for example, digits equal to or greater than 1 km / L) of the fuel efficiency or electricity efficiency is set as low update frequency data DL, and the data in the lower digits (digits less than 1 km / L) is set as high update frequency data DH.

[0065] Furthermore, when the to-be-saved data D is a display screen parameter, among the display screen parameters, the screen setting information is set as low update frequency data DL, and the display screen information at the time of the end of driving is set as high update frequency data.

[0066] The above is a description of the embodiment of the display device for vehicle M of the present disclosure.

[0067] The display device M for a vehicle according to the present disclosure includes a display 2 for displaying an image, and a multi-core SOC 1 for displaying an image showing vehicle information on the display 2. The display device M for a vehicle also includes a first power supply circuit 54 for stepping down a battery power source supplied from an in-vehicle battery BAT to a first voltage and supplying the first power source. The display device M for a vehicle also includes a second power supply circuit 55 for stepping down the first power source supplied from the first power supply circuit 54 to a second voltage and supplying the second voltage to the display 2 and the SOC 1. The display device M for a vehicle also includes a reset circuit 4 for outputting a reset signal to the SOC 1 based on the voltage output by the first power supply circuit 54. As a result, the reset circuit 4 operates based on the output voltage of the first power supply circuit 54, which has a higher output voltage than the second power supply circuit 55, so that the reset circuit 4 can be operated appropriately to start the SOC 1 even when the voltage of the battery power source drops.

[0068] Moreover, the SOC1 includes a first processor core 11A and a second processor core 11B. The second power supply circuit 55 supplies power to the first processor core 11A. The vehicle display device M further includes a third power supply circuit 53 that steps down the battery power supplied from the vehicle battery BAT and supplies power to the second processor core 11B. When an operation to end the traveling of the vehicle is performed, the second processor core 11B stops the supply of power to the first power supply circuit 53. This causes the vehicle display device M to enter a power saving mode, thereby reducing power consumption.

[0069] Furthermore, when an operation to start driving the vehicle is performed, the second processor core 11B starts supplying power to the first power supply circuit 54. This causes the vehicle display device M to transition from the power saving mode to the normal operation mode, and also causes the reset circuit 4 to operate to start up the SOC1 (the first processor core 11A). [Explanation of symbols]

[0070] M … Vehicle display device 1. State of Organisation 11A ... 1st processor core 11B ... 2nd processor core 11B1…Internal memory 11C ... 3rd processor core 12 …PVT monitor section 13. Communications Department 14 ...Video input section 15 ... Display control unit 16...ROM 17. RAM 18 ... 2D drawing section 19...3D drawing section 2. Display 3...Timekeeping section 4. Reset circuit 5…Power circuit 51 ... Diode 52... Capacitor 53...Third power supply circuit 54...1st power supply circuit 55...Second power supply circuit BAT … Vehicle battery C … Car camera E … Vehicle control unit N … In-vehicle network

Claims

1. A display for displaying an image; A vehicle display device including: a first power supply circuit that steps down a battery power source supplied from an in-vehicle battery to a first voltage and supplies the first power supply; a second power supply circuit that steps down the first power supply supplied from the first power supply circuit to a second voltage and supplies the second voltage to the display and the SOC; A reset circuit that outputs a reset signal to the SOC based on a voltage output by the first power supply circuit. Vehicle display device.

2. the SOC comprises a first processor core and a second processor core; the second power supply circuit supplies power to the first processor core; a third power supply circuit that steps down a battery power source supplied from the vehicle battery and supplies the second processor core with power; the second processor core stops the supply of power to the first power supply circuit when an operation to end driving of the vehicle is performed; The display device for a vehicle according to claim 1 .

3. the second processor core causes the first power supply circuit to start supplying power when an operation to start driving the vehicle is performed; The display device for a vehicle according to claim 2 .

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