Vehicle Electronic Control Unit

Abstract

To provide an electronic control apparatus for a vehicle, configured so that a microcomputer may reliably execute reset preprocessing even if a large current is consumed by the microcomputer.SOLUTION: A first power supply circuit 5 actuates a microcomputer 8 on the basis of outputting a VB voltage adjusted to a first power supply voltage. A switch M1 is connected between a second input node N2 to which a BATT voltage is input and a first input node N1 to which the VB voltage is input. A switch control circuit controls the switch M1 to be turned on / off. When the VB voltage falls below a predetermined first threshold voltage that makes a first power supply voltage Vo6 of the first power supply circuit 5 lower than a predetermined output threshold voltage, the switch control circuit turns on the switch M1 to cause the BATT voltage to be input to the first input node N1. The first power supply circuit 5 outputs the first power supply voltage Vo6 adjusted to a power supply voltage value which is lower than the output threshold voltage, to maintain operation of the microcomputer 8.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electronic control device for a vehicle. [Background technology]

[0002] When an initialization command is issued, the microcomputer executes various processes such as saving data before the microcomputer is stopped after the initialization command is issued. For this reason, it is necessary to continue supplying the microcomputer with a voltage that guarantees the operation of the microcomputer for a predetermined time (e.g., 2 μs) or more after the initialization command is issued.

[0003] Normally, when a microcontroller executes pre-reset processing, it uses the time it takes for the stored power in a capacitor mounted in the power supply circuit to be discharged. If such a conventional technique is applied, a large-capacity capacitor must be mounted, which is less practical in terms of cost and the mounting area of ​​the capacitor.

[0004] In addition, in the conventional configuration, since the configuration relies on the discharge time of the power stored in the capacitor, the discharge time becomes shorter when the current consumption of the microcomputer increases. In recent years, as the current consumption of the microcomputer increases, it has become difficult to continue supplying power to the microcomputer for a predetermined period of time using only the discharge time of the capacitor. Note that the technology described in Patent Document 1 is provided as a technology related to the present application. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-266547 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide an electronic control device for a vehicle that enables a microcomputer to reliably execute pre-reset processing even if the microcomputer consumes a large current. [Means for solving the problem]

[0007] According to the invention of claim 1, the operation is as follows. The first power supply circuit adjusts the first voltage to the first power supply voltage and outputs the adjusted first voltage to operate the microcomputer. The switch is connected between a second input node that inputs the second voltage and a first input node that inputs the first voltage. The switch control circuit controls the switch to be turned on and off.

[0008] When the first voltage falls below a predetermined first threshold voltage that causes the first power supply voltage of the first power supply circuit to fall below a predetermined output threshold voltage, the switch control circuit turns on the switch to input the second voltage to the first input node. The first power supply circuit also adjusts the first power supply voltage to a power supply voltage value lower than the output threshold voltage and outputs it to maintain operation of the microcomputer. Since it becomes possible to maintain operation of the microcomputer, pre-reset processing can be reliably executed even if the current consumption of the microcomputer increases. The first power supply circuit continues to output the power supply voltage value for a certain period of time to ensure preprocessing time before the microcontroller is reset, and after the microcontroller has completed initialization, the switch control circuit turns off the switch, stopping the voltage adjustment operation of the first power supply circuit and shutting it down. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an electrical configuration block diagram of a vehicle electronic control device according to a first embodiment; [Diagram 2] Example of circuit configuration of power supply IC and first power supply circuit [Diagram 3] Example of circuit configuration of second power supply circuit and third power supply circuit [Figure 4] 1 is a flow chart showing an outline of the operation [Diagram 5] Time Chart [Figure 6] Time chart of comparative example [Figure 7] Explanation of the difference from the background art DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment of an electronic control device for a vehicle will be described below with reference to the drawings. FIG. 1 shows a schematic electrical configuration of an electronic control device 1 for a vehicle. The electronic control device 1 inputs a VB voltage, which is a first voltage, to a first input node N1 through a VB terminal T1. This VB voltage is supplied from an in-vehicle battery 3 through a main relay 2, which is a start switch for the vehicle. The VB voltage is a power supply supplied as a main power supply for the electronic control device 1, and is normally set to a standard value of about 14V. In addition, the electronic control device 1 inputs a BATT voltage, which is a second voltage constantly supplied from the in-vehicle battery 3, to a second input node N2 through a BATT terminal T2.

[0011] The electronic control device 1 includes a power supply IC 4, a first power supply circuit 5, a second power supply circuit 6, a third power supply circuit 7, a microcomputer 8, and an initialization command circuit 9. The first input node N1 is connected to the first power supply circuit 5, and the first power supply circuit 5 generates a first power supply voltage Vo6 based on the VB voltage input from the first input node N1. The second power supply circuit 6 generates a second power supply voltage Vo5 to be supplied to the microcomputer 8 based on the first power supply voltage Vo6 of the first power supply circuit 5. The third power supply circuit 7 generates a third power supply voltage Vo1 to be supplied to the microcomputer 8 based on the first power supply voltage Vo6 of the first power supply circuit 5. This allows the first power supply circuit 5 to operate the microcomputer 8 by adjusting the VB voltage to the first power supply voltage Vo6 and outputting it.

[0012] The microcomputer 8 is configured by combining a processor, RAM, ROM, non-volatile memory, A / D conversion circuit, communication circuit (none of which are shown), etc., and executes predetermined vehicle control while power is being supplied. Also, during shutdown when the supply of power supply voltage is cut off, the microcomputer 8 is configured to save data temporarily stored in the work memory of the RAM, etc., to the non-volatile memory and then stop.

[0013] Furthermore, the initialization command circuit 9 outputs a reset signal INIT to the microcomputer 8 when the second power supply voltage Vo5 of the second power supply circuit 6 or the third power supply voltage Vo1 of the third power supply circuit 7 drops to an abnormal threshold voltage indicating an abnormality. The initialization command circuit 9 monitors the second power supply voltage Vo5 of the second power supply circuit 6 or the power supply voltage Vo1 of the third power supply circuit 7, and when the voltage supplied to the microcomputer 8 becomes abnormal, outputs an initialization command to the microcomputer 8 and resets, i.e., initializes, the microcomputer 8. In other words, the initialization command circuit 9 monitors the power supply voltages Vo5 and Vo1, and when it is determined that the voltage supplied to the microcomputer 8 is abnormal, it can reset the microcomputer 8.

[0014] On the other hand, a switch M1 is connected between a second input node N2 for inputting a BATT voltage and a first input node N1 for inputting a VB voltage. The switch M1 is a MOSFET and is capable of turning on and off the electrical current between the first input node N1 and the second input node N2.

[0015] 2, the first power supply circuit 5 is a power supply circuit that operates when driven by a power supply IC4, and is a switching power supply circuit configured by combining MOS transistors M2 and M3, an inductor Lo, and a capacitor Co in the illustrated form. The drain-sources of the MOS transistors M2 and M3 are connected in series between a node N1 and ground, and the inductor Lo and the capacitor Co are connected in series between a common connection point of these MOS transistors M2 and M3 and ground, and a first power supply voltage Vo6 is output from the common connection point of the inductor Lo and the capacitor Co.

[0016] The power supply IC 4 includes a switch control circuit 11, a changeover switch 12, a first threshold setting unit 13, a second threshold setting unit 14, and a duty signal generating circuit 15. The switch control circuit 11 controls the on / off of the switch M1 based on the detection state of the first power supply voltage Vo6 of the first power supply circuit 5.

[0017] The changeover switch 12 receives a predetermined first threshold from a first threshold setting unit 13 and a predetermined second threshold from a second threshold setting unit 14. The changeover switch 12 is normally switched to the side of the first threshold setting unit 13 and outputs the first threshold of the first threshold setting unit 13 to the duty signal generating circuit 15. At this time, the duty signal generating circuit 15 applies complementary pulses to the MOS transistors M2 and M3 and adjusts the duty ratio of the pulses to adjust and output the first power supply voltage Vo6 to a predetermined power supply voltage value Vo6b (for example, 6.0 V).

[0018] When the first power supply voltage Vo6 of the first power supply circuit 5 falls below a predetermined threshold, the switch control circuit 11 turns on the switch M1, and the changeover switch 12 switches to the side of the second threshold setting unit 14, thereby outputting a second threshold to the duty signal generating circuit 15. The duty signal generating circuit 15 outputs a power supply voltage value Vo6b within a predetermined range from the first power supply circuit 5 based on the second threshold, as will be described in detail later. This power supply voltage value Vo6b is a voltage value that is set lower than the aforementioned predetermined power supply voltage value Vo6a.

[0019] 3, the second power supply circuit 6 is a series power supply circuit that outputs a power supply voltage of, for example, 5.0 V as the second power supply voltage Vo5 by controlling the gate of the MOS transistor M4 by the second power supply control circuit 21. The microcomputer 8 uses the second power supply voltage Vo5 as a reference voltage for the A / D conversion circuit.

[0020] The third power supply circuit 7 is a switching power supply circuit that includes a third power supply control circuit 31, MOS transistors M5 and M6, an inductor Lo2, and a capacitor Co2, and outputs, for example, 1 V as a third power supply voltage Vo1. The microcomputer 8 uses the third power supply voltage Vo1 as the core power supply of the microcomputer 8. In order for the microcomputer 8 to continue operating, it is necessary to ensure the guaranteed operating range of the core power supply.

[0021] The power supply operation to the microcomputer 8 in the above configuration will be described with reference to the flowchart shown in Fig. 4 and the drawings from Fig. 5 onwards. Normally, the switch control circuit 11 of the power supply IC 4 turns off the switch M1 at S1, and with the switch M1 in the off state, the power supply IC 4 drives the first power supply circuit 5. Normally, the power supply IC 4 switches the changeover switch 12 to the side of the first threshold setting unit 13 to input the first threshold of the first threshold setting unit 13 to the duty signal generating circuit 15.

[0022] The duty signal generating circuit 15 applies complementary PWM pulses to the MOS transistors M2 and M3 and adjusts the duty ratio of the PWM pulses to adjust and output the first power supply voltage Vo6 to a predetermined power supply voltage value Vo6b (for example, 6.0 V).

[0023] The power supply IC 4 detects the first power supply voltage Vo6 as the output voltage of the first power supply circuit 5, and determines whether the first power supply voltage Vo6 exceeds a threshold voltage Vt1 (e.g., 4.6 V) in S2. When the first power supply voltage Vo6 exceeds the threshold voltage Vt1, the power supply IC 4 continues to supply power by setting the above-mentioned predetermined power supply voltage value Vo6a (e.g., 6.0 V) as the target value of the first power supply voltage Vo6 in S3 as normal operation.

[0024] On the other hand, the second power supply circuit 6 and the third power supply circuit 7 receive the first power supply voltage Vo6 of the first power supply circuit 5, generate the second power supply voltage Vo5 and the third power supply voltage Vo1, and supply them to the microcomputer 8. At this time, the second power supply circuit 6 outputs a predetermined power supply voltage value Vo5a (e.g., 5.0 V) as the second power supply voltage Vo5, and the third power supply circuit 7 outputs a predetermined power supply voltage value Vo1a (e.g., 1.0 V) as the third power supply voltage Vo1. On the other hand, the initialization command circuit 9 confirms that neither the power supply voltage Vo5 nor Vo1 of the second power supply circuit 6 or the third power supply circuit 7 is abnormal, and therefore does not output an initialization command to the microcomputer 8. This allows the microcomputer 8 to operate normally.

[0025] However, as shown in Fig. 5, when the VB voltage drops from timing t0, the first power supply voltage Vo6 also drops. After that, if the VB voltage drops below a predetermined first threshold voltage Vtb at timing t1 and the first power supply voltage Vo6 of the first power supply circuit 5 drops below a predetermined output threshold voltage Vt1a, the determination is NO in S2 in Fig. 4 and the process proceeds to step S4.

[0026] The switch control circuit 11 turns on the switch M1 in S4, thereby inputting the BATT voltage input to the second input node N2 to the first input node N1. The voltage of the first input node N1 is maintained to be as high as possible due to the supply capacity of the BATT voltage even if the VB voltage drops below the first threshold voltage Vtb. At this time, the power supply IC4 switches the changeover switch 12 from the first threshold setting unit 13 side to the second threshold setting unit 14 side, and inputs the second threshold to the duty signal generating circuit 15.

[0027] When the duty signal generating circuit 15 receives the second threshold, it adjusts the duty ratio of the PWM pulse according to the second threshold, and outputs the first power supply voltage Vo6 by the first power supply circuit 5 in S5, with a power supply voltage value Vo6b (e.g., 4.3 V) lower than the output threshold voltage Vt1a as a target value. It is desirable to set this target power supply voltage value Vo6b to a voltage within a predetermined voltage range that is lower than the initialization threshold Vti (e.g., 4.5 V) and exceeds a predetermined lower limit voltage (e.g., 4.0 V). Then, it is possible to continue to supply the operating voltage to the microcomputer 8 at the time of shutdown, without returning to the voltage during normal operation that exceeds the initialization threshold Vti.

[0028] The switch control circuit 11 of the power supply IC 4 holds the switch M1 in the on state for a predetermined time (e.g., 100 μs) and then turns it off. Note that in the example shown in Fig. 5, the switch M1 is turned on for a predetermined time from a certain timing t2a after the timing t2.

[0029] Then, during the predetermined time from timing t2a to timing t4, the first power supply circuit 5 can maintain the power supply voltage value Vo6b as the first power supply voltage Vo6. The second power supply circuit 6 can generate the second power supply voltage Vo5 based on this power supply voltage value Vo6b, and can maintain a predetermined power supply voltage value Vo5b as the second power supply voltage Vo5 to be output. On the other hand, the third power supply circuit 7 also generates the third power supply voltage Vo1 based on the power supply voltage value Vo6b, and can maintain a predetermined power supply voltage value Vo1a as the third power supply voltage Vo1 to be output. In other words, the third power supply circuit 7 can adjust and output the power supply voltage value Vo1a as the third power supply voltage Vo1 so that it is equal to or higher than the voltage Vmin at which the microcomputer 8 can be operated.

[0030] On the other hand, when the initialization delay time Td has elapsed from the timing t2 when the second power supply voltage Vo5 falls below the initialization threshold Vti (for example, 4.5 V), the initialization command circuit 9 outputs a reset signal INIT at timing t3. When the reset signal INIT is input, the microcomputer 8 executes a process of saving the working memory data of the RAM to the non-volatile memory.

[0031] The microcomputer 8 requires a predetermined preprocessing time Td2 (see FIG. 5) to execute this procedure, but because the time that the power supply voltage is supplied to the microcomputer 8 is extended to a length exceeding the predetermined time Td+preprocessing time Td2 by the third power supply voltage Vo1 of the third power supply circuit 7, the microcomputer 8 can execute the save procedure with the core voltage input within the guaranteed operation range. This enables the microcomputer 8 to execute the preprocessing for shutdown, which saves the working memory data in the RAM to the nonvolatile memory.

[0032] After the microcomputer 8 completes the initialization process, the switch control circuit 11 turns off the switch M1 at timing t4, and then the power supply IC 4 can shut down at S7 in Fig. 4 by stopping the voltage adjustment operations of the first power supply circuit 5, the second power supply circuit 6, and the third power supply circuit 7. This makes it possible to stop the operations of the first power supply circuit 5, the second power supply circuit 6, and the third power supply circuit 7, and to take measures such as saving data in the RAM to a non-volatile memory before the microcomputer 8 shuts down, thereby ensuring the pre-processing time Td2.

[0033] <Comparative Example> Figure 6 shows the operation in the comparative example. This operation in Figure 6 shows an example of operation in the case where the switch M1 is not provided in the configuration in Figure 1. If the switch M1 is not provided, the BATT voltage cannot be supplied from the vehicle battery 3. In this case, even when the VB voltage starts to decrease from the timing t0 in Figure 6, the first power supply circuit 5 continues to generate the first power supply voltage Vo6 based on the VB voltage.

[0034] Then, the initialization command circuit 9 outputs the reset signal INIT to the microcomputer 8 after the second power supply voltage Vo5 of the second power supply circuit 6 drops below the initialization threshold Vti and the initialization delay time Td has elapsed. Therefore, the microcomputer 8 executes pre-shutdown processing from timing t3 when the reset signal INIT is input. The third power supply circuit 7 supplies the third power supply voltage Vo1 using the power stored in the capacitor Co3. However, due to the increase in power consumption, it is becoming difficult to secure the necessary power for the microcomputer 8 to continue operating for the pre-processing time Td2. In order to secure the necessary power, a capacitor Co3 with a larger capacity is required, which raises concerns about the installation cost and the size of the circuit area.

[0035] <Summary of this embodiment> In contrast, according to this embodiment, the first power supply circuit 5 adjusts the first power supply voltage Vo6 to a power supply voltage value Vo6b lower than the output threshold voltage Vt1a, outputs the adjusted voltage, and continues to output the voltage for a predetermined period of time, thereby ensuring the preprocessing time Td2 by the microcomputer 8. During the preprocessing time Td2, the microcomputer 8 can take measures such as saving the work memory data in the RAM to the non-volatile memory. This allows the time that the voltage is supplied from the BATT voltage to the microcomputer 8 during shutdown to be extended.

[0036] In particular, during the preprocessing time Td2 executed by the microcomputer 8, the BATT voltage is supplied to the first power supply circuit 5 through the BATT terminal T2, and power generation by the first power supply circuit 5 can be supported.

[0037] By turning on switch M1, the power supply time can be secured by the BATT voltage, the pre-processing time Td2 for initialization can be secured, and the capacitance of the downstream capacitor Co2 that constitutes the third power supply circuit 7 can be reduced, resulting in an advantageous configuration in terms of both cost and circuit area.

[0038] In the above description, the switch M1 is turned on for a predetermined time from timing t2a to timing t4. However, this is not limited to the above. The switch M1 may be turned on for a predetermined time from timing t2, or may be turned on for a predetermined time from timing t1 when the first power supply voltage Vo6 falls below a predetermined output threshold voltage Vt1a.

[0039] <Comparison with the technology described in Patent Document 1 as a comparative example> Hereinafter, a comparison will be made between this embodiment and the technology described in Patent Document 1. In the configuration of Patent Document 1 shown in the Background section, it is necessary to prepare two power supply circuits, one for inputting a +B voltage equivalent to the VB voltage, and the other for inputting a BATT voltage, and connect them in parallel.

[0040] In contrast, in this embodiment, by preparing one system of the first power supply circuit 5, the second power supply circuit 6 and the third power supply circuit 7 can generate the power supply voltages Vo5 and Vo1 based on the first power supply voltage Vo6, and only one switch M1 needs to be added. In other words, it is no longer necessary to prepare two systems of power supply circuits that generate voltages from the original VB voltage or BATT voltage.

[0041] Furthermore, as shown in FIG. 7, if the target value of the first power supply voltage Vo6 is returned to the initial power supply voltage value Vo6a after the first power supply voltage Vo6 falls below the initialization threshold Vti, the microcontroller 8 will be supplied with the normal power supply voltage values ​​Vo6a, Vo5a, and Vo1a as the first power supply voltage Vo6, the second power supply voltage Vo5, and the third power supply voltage Vo1, respectively, and the microcontroller 8 will no longer be able to maintain the initialized state after timing t10, and the microcontroller 8 will no longer be able to be reset normally.

[0042] In this embodiment, the first power supply voltage Vo6 is maintained at a predetermined voltage (e.g., 4.3 V) lower than the initialization threshold Vti, so that the microcomputer 8 can maintain the initialized state. In this way, this embodiment differs from the technology described in Patent Document 1.

[0043] (Other embodiments) The present invention is not limited to the above-described embodiment, and the following modifications and extensions are possible. The second power supply circuit 6 and the third power supply circuit 7 may be provided as necessary. Also, the present invention can be applied to a configuration in which another power supply circuit is provided to supply a power supply voltage to the microcomputer 8. The electronic control device 1 and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the electronic control device 1 and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the electronic control device 1 and the method described in the present disclosure may be realized by one or more special-purpose computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. Also, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executed by a computer.

[0044] Although the present disclosure has been described based on the embodiment, it is understood that the present disclosure is not limited to the embodiment or structure. The present disclosure also encompasses various modifications and modifications within the equivalent range. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure. [Explanation of symbols]

[0045] In the drawing, 5 is a first power supply circuit, 6 is a second power supply circuit, 7 is a third power supply circuit, 8 is a microcomputer, M1 is a switch, 11 is a switch control circuit, N1 is a first input node, and N2 is a second input node.

Claims

1. 1. An electronic control device for a vehicle that receives a first voltage supplied from an on-board battery via a start switch of the vehicle and a second voltage constantly supplied from the on-board battery, a first power supply circuit (5) that adjusts the first voltage to a first power supply voltage and outputs the adjusted first voltage to operate a microcomputer; a switch (M1) connected between a second input node (N2) for inputting the second voltage and a first input node (N1) for inputting the first voltage; A switch control circuit (11) that controls the switch to be turned on and off, when the first voltage drops below a predetermined first threshold voltage that causes the first power supply voltage of the first power supply circuit to drop below a predetermined output threshold voltage; the switch control circuit turns on the switch to input the second voltage to the first input node; the first power supply circuit adjusts the first power supply voltage to a power supply voltage value lower than the output threshold voltage and outputs the adjusted first power supply voltage to maintain operation of the microcomputer; The first power supply circuit continues to output the power supply voltage value for a certain period of time, thereby securing a pre-processing time before the microcomputer is reset, and after the microcomputer completes initialization, The switch control circuit stops the voltage regulation operation of the first power supply circuit and shuts down the first power supply circuit by turning off the switch.

2. 2. The electronic control device for a vehicle according to claim 1, wherein the first power supply circuit adjusts and outputs the power supply voltage so that the power supply voltage is equal to or higher than a voltage at which the microcomputer can continue to operate.

3. a second power supply circuit (6) that generates a second power supply voltage to be supplied to the microcomputer based on a first power supply voltage of the first power supply circuit; a third power supply circuit (7) that generates a third power supply voltage to be supplied to the microcomputer based on the first power supply voltage of the first power supply circuit; an initialization command circuit (9) that outputs a reset signal to the microcomputer when the second power supply voltage of the second power supply circuit or the third power supply voltage of the third power supply circuit drops to an abnormality threshold voltage indicating an abnormality; The electronic control device for a vehicle according to claim 1 ,

Images