On-board power supply device

Abstract

To provide an on-vehicle power supply apparatus that can maintain supply of power from a power source to an important load and reduce dark currents which are consumed by a redundant function or the like, even when a defect occurs in the power source of a vehicle.SOLUTION: An on-vehicle power supply apparatus is provided with a main power supply part including a semiconductor switch IPD3 in a zone ECU 10 and a bypass circuit 14 which supply power from a power source of a main battery 21 or of a sub battery 23 to an important load 33 that regularly requires supply of power from the power source, from the zone ECU 10. The bypass circuit 14 has a bypass route bypassing the semiconductor switch IPD3, which can supply necessary power from the power source to the important load 33 even when the semiconductor switch IPD3 is in an OFF-state. Further the circuit can turn off the semiconductor switch IPD3 or the like while maintaining a function of the important load 33 to reduce dark currents, and suppress currents flowing into the important load 33 to the requisite minimum using a resistor 14a of the bypass circuit 14. The apparatus wakes up from a sleep state by detection of a busy state of a communication bus.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an on-board power supply device. [Background technology]

[0002] In a vehicle, various electrical devices are distributed and arranged in various locations on the vehicle body. For example, electrical devices related to the running of the vehicle, electrical devices related to audio, electrical devices related to the functions of the vehicle body, etc. are arranged in various locations such as the steering column, glove box, center cluster, center console, etc. Each of these electrical devices usually includes various switches, various sensors, various loads, control relays, etc.

[0003] These various electrical devices need to be supplied with power from the vehicle's main power source (vehicle battery or alternator). In addition, signals from switches and sensors in each electrical device need to be transmitted to other electrical devices or to various electronic control devices (ECUs) mounted on the vehicle. Therefore, conventionally, the vehicle's power source is connected to the various electrical devices and various electronic control devices via a wire harness. Such a wire harness is generally formed by bundling a large number of electric wires.

[0004] Meanwhile, in recent years, with the advancement of autonomous driving and driving assistance technologies, the number of sensors, electric loads, ECUs, etc. installed in vehicles is steadily increasing. In addition, autonomous vehicles need to maintain a minimum level of functionality even if the on-board battery or alternator fails. For this reason, vehicles are equipped with multiple batteries to provide redundant power sources.

[0005] For example, Patent Document 1 discloses a technique for improving the reliability of power supply to a load by using a bidirectional DC-DC converter when a main battery and a sub-battery are used to provide a redundant power source.

[0006] Furthermore, Patent Document 2 discloses that in a power distribution system for a vehicle, a plurality of power supply boxes each have a built-in DC-DC converter, and the power supply power distributed via a switching device is supplied to each load. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2018-196252 A [Patent Document 2] JP 2016-43882 A Summary of the Invention [Problem to be solved by the invention]

[0008] By utilizing the technologies disclosed in Patent Documents 1 and 2, even if some kind of malfunction occurs in the vehicle's power supply, such as a broken wire harness or a disconnected battery, it is possible to constantly supply power to important loads such as the brake device.

[0009] However, in order to constantly supply power to important loads, the DC-DC converter and switching device as shown in Patent Document 2 must be constantly kept on. Therefore, the DC-DC converter and switching device constantly consume a power supply current of several mA to several tens of mA, which raises concerns about an increase in the dark current of the entire vehicle.

[0010] That is, even when the vehicle is not in operation and in standby mode, the power stored in the on-board battery decreases due to the consumption of power from the power source by dark current, so it is possible that the battery may run out, for example, while the vehicle is parked for a long period of time. In addition, sub-batteries generally have a small amount of stored power, so they are prone to running out.

[0011] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide an in-vehicle power supply device that can maintain the supply of power source power to important loads even when a malfunction occurs in the vehicle's power supply, and can reduce dark current consumed by redundancy functions, etc. [Means for solving the problem]

[0012] In order to achieve the above object, the in-vehicle power supply device according to the present invention is characterized by the following (1) to (5). (1) An on-board power supply device that supplies power from a first on-board power source or a second on-board power source to a predetermined important load that requires a constant supply of power from a power source on a vehicle, the critical load having a first power terminal and a second power terminal; The output power of the first on-board power supply is supplied to the important load through a main path via a main semiconductor switch. The first power supply terminal a main power supply for supplying the The output power of the second on-board power supply is supplied to the important load through a sub-path via a sub semiconductor switch. The second power supply terminal a sub-power supply unit for supplying the The output power of the first vehicle power supply or the second vehicle power supply is supplied to the important load through a bypass path that bypasses at least the main semiconductor switch and the sub semiconductor switch. The first power supply terminal a bypass power supply unit for supplying An in-vehicle power supply device comprising:

[0013] (2) An on-board power supply device that supplies power source power from a first on-board power source or a second on-board power source to a predetermined important load that constantly requires a power source power supply on a vehicle, a main power supply unit that supplies the output power of the first vehicle power supply to an input side of the important load through a main path via a main semiconductor switch; a sub-power supply unit that supplies the output power of the second vehicle power supply to an input side of the important load through a sub-path that passes through a sub-semiconductor switch; a bypass power supply unit that supplies output power of the first vehicle power supply or the second vehicle power supply to an input side of the important load through a bypass path that bypasses at least the main semiconductor switch and the sub semiconductor switch; Equipped with a control unit for controlling the main semiconductor switch, The control unit is In a predetermined standby state, the main semiconductor switch is controlled to be off, and when communication is received from at least the important load side, the wake-up state is transitioned to and the main semiconductor switch is controlled to be on. On-board power supply device .

[0014] (3) The bypass path has a current suppression unit that suppresses a current flowing downstream of the bypass path. An in-vehicle power supply device according to (1) or (2) above.

[0015] (4) an input side of the bypass power supply unit is connected to an output of the second vehicle power supply, The vehicle-mounted power supply device according to any one of (1) to (3) above.

[0016] (5) a first output voltage output by the first vehicle-mounted power supply is higher than a second output voltage output by the second vehicle-mounted power supply; a voltage conversion unit that reduces the first output voltage to a voltage close to the second output voltage; the voltage conversion unit is connected to an output side of the first vehicle power supply, The main semiconductor switch is connected to an output side of the voltage conversion unit. The vehicle-mounted power supply device according to (4) above.

[0017] According to the on-board power supply device having the configuration of (1) above, since a plurality of on-board power supplies are provided, a power supply redundancy function can be realized. In addition, since the bypass power supply unit uses a bypass route that bypasses the main semiconductor switch and the sub semiconductor switch, even if these semiconductor switches are in the off state, the power supply power can be constantly supplied to the input side of the important load. Therefore, in the main power supply unit, it is no longer necessary to keep the main semiconductor switch on all the time, and it is possible to reduce the dark current.

[0018] According to the in-vehicle power supply device having the configuration of (2) above, the main semiconductor switch is turned off in the standby state, so that the dark current consumed by the main semiconductor switch can be reduced. Also, when the important load is started, the control unit receives communication from the important load and transitions to wake-up, so that the power source power can be supplied to the important load via the main path. For example, when the input side of the bypass path is connected to a sub-battery, the power consumption of the sub-battery can be suppressed by switching on the power supply of the main path, so that the sub-battery can be made smaller.

[0019] According to the in-vehicle power supply device having the above configuration (3), the current suppression unit suppresses the current flowing downstream, so that the current flowing from the bypass path to the important load in the standby state can be limited. Therefore, for example, when the input side of the bypass path is connected to the sub-battery, the power consumption of the sub-battery can be suppressed, so that the sub-battery can be made smaller.

[0020] According to the in-vehicle power supply device having the configuration of (4) above, it is not necessary to use the first in-vehicle power supply in the standby state. For example, when the output voltage of the first in-vehicle power supply is higher than the power supply voltage required by the important load, it is necessary to generate stepped-down power supply using a specified DCDC converter. However, by supplying power supply from the output of the second in-vehicle power supply to the input of the bypass power supply unit, it is not necessary to use the DCDC converter, and the dark current is reduced.

[0021] According to the in-vehicle power supply device having the above configuration (5), it is easy to reduce power loss occurring in a power distribution path such as a wire harness on the output side of the first in-vehicle power source by increasing the first output voltage. In addition, by using a voltage conversion unit, it is possible to supply power from multiple systems to important loads, thereby realizing power source redundancy. Effect of the Invention

[0022] According to the in-vehicle power supply device of the present invention, even if a malfunction occurs in the vehicle's power supply, it is possible to maintain the supply of power from the power source to important loads, and it is possible to reduce the dark current consumed by redundancy functions, etc.

[0023] The present invention has been briefly described above. Furthermore, the details of the present invention will be further clarified by reading the following description of the embodiment of the present invention (hereinafter, referred to as "embodiment") with reference to the accompanying drawings. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a block diagram showing a configuration example 1 of a power supply device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a flowchart showing an example of control for state transition of the zone ECU shown in FIG. [Diagram 3] FIG. 3 is a block diagram showing a second configuration example of a power supply device according to an embodiment of the present invention. [Figure 4] FIG. 4 is a block diagram showing a third configuration example of a power supply device according to an embodiment of the present invention. [Diagram 5] FIG. 5 is a flowchart showing an example of control for state transition of the zone ECU shown in FIG. [Figure 6] FIG. 6 is a block diagram showing a fourth configuration example of a power supply device according to an embodiment of the present invention. [Figure 7] FIG. 7 is a block diagram showing a fifth configuration example of a power supply device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0026] FIG. 1 is a block diagram showing a first configuration example of a power supply device 100 according to an embodiment of the present invention.

[0027] The power supply device 100 shown in Fig. 1 is used to supply power from an on-board power source to various on-board devices mounted on a vehicle and connected as loads. In the example shown in Fig. 1, the power supply device 100 includes a main battery (BAT) 21, an alternator (ALT) 22, and a sub-battery 23 as on-board power sources. In this example, the main battery 21 and the alternator 22 output DC power source power with a voltage of 48 [V]. The sub-battery 23 outputs DC power source power with a voltage of 12 [V].

[0028] For example, in the case of an electric vehicle equipped with a high-voltage power supply device that outputs a high voltage of several hundred volts, a DC / DC converter is installed instead of the alternator 22. The DC / DC converter converts the high voltage of several hundred volts to a voltage of 48 volts and outputs it.

[0029] 1, the power supply device 100 has two systems, a main battery 21 and a sub-battery 23, as on-board power sources, so that the power supply function can be made redundant. For example, if a malfunction such as battery removal or wire breakage occurs on the main battery 21 side, power is supplied to important loads from the sub-battery 23 side instead of the main battery 21. This makes it possible to prevent important functions on the vehicle from being lost.

[0030] The sub-battery 23 is assigned a function of a backup power supply that enables a short-term supply of power only to important loads when the vehicle's power supply fails. Therefore, the sub-battery 23 is smaller and lighter than the main battery 21, and the amount of power that can be stored is relatively small.

[0031] 1, the main functions of the power supply device 100 are mounted in the zone ECU 10. The zone ECU 10 has a function for managing the power supply to the loads in a specific zone on the vehicle. Note that the zone may be assigned to an area representing a specific space on the vehicle, or may be assigned to a specific functional group.

[0032] A power input terminal 10a of the zone ECU 10 is connected to the output of the main battery 21 via fuses 24, 25 and a power line 27. A power input terminal 10b of the zone ECU 10 is connected to the output of the sub-battery 23 via a fuse 26 and a power line 28. In addition, a communication terminal 10c of the zone ECU 10 is connected to an electric wire of a communication bus 29 provided on the vehicle.

[0033] Moreover, an output terminal 10d of the zone ECU 10 is connected to a load 31 requiring a power supply of 48 V. An output terminal 10e of the zone ECU 10 is connected to a load 32 requiring a power supply of 12 V. Moreover, output terminals 10f and 10g of the zone ECU 10 are connected to power supply terminals 33a and 33b of an important load 33 via power supply lines 51 and 52, respectively.

[0034] The important load 33 is assigned to a device that is important for the vehicle to be able to constantly supply power, such as a special ECU that controls the vehicle's brake system. Therefore, the important load 33 has a power terminal 33a of "+B" that is required to be always on (ON) regardless of the ignition on / off, and a power terminal 33b that requires power supply only when the ignition is on. The power voltage required by the power terminals 33a and 33b is both 12 [V]. In addition, the communication terminal 33c of the important load 33 is connected to the communication bus 29.

[0035] The zone ECU 10 incorporates four semiconductor switches IPD1, IPD2, IPD3, and IPD4 to enable on / off switching of power supply to each of the four output terminals 10d, 10e, 10f, and 10g. These semiconductor switches IPD1 to IPD4 are high-performance semiconductor switches (IPD: Intelligent Power Devices) having a protection function.

[0036] The zone ECU 10 also includes a controller 12 for individually controlling the on / off of the four semiconductor switches IPD1 to IPD4. Although only a portion of the controller 12 is shown in Fig. 1, the four outputs of the controller 12 are actually connected to the control input terminals of the semiconductor switches IPD1 to IPD4, respectively.

[0037] Further, in order to step down the power supply voltage of 48 [V] supplied to the power supply input terminal 10a to power supply voltage of 12 [V], a DC / DC converter 11 is built into the zone ECU 10. The input side of the DC / DC converter 11 is connected to the power supply input terminal 10a via a power supply line 41, and the output side is connected to the inputs of the semiconductor switches IPD2 and IPD3 via a power supply line 42.

[0038] The zone ECU 10 also includes a microcomputer (μC) 13 to enable switching of the operation mode of the power saving function. A communication interface built into the microcomputer 13 is connected to the communication terminal 10c. A plurality of outputs of the microcomputer 13 are also connected to the control input terminals of the DC / DC converter 11 and the control unit 12, respectively.

[0039] The operation modes of the power saving function include a sleep mode, which is a standby state in which almost no power is consumed, and a normal mode. As will be described later, the microcomputer 13 can automatically switch between the sleep mode and the normal mode.

[0040] 1, the semiconductor switch IPD1 has an input side connected to the power supply input terminal 10a via the power supply line 41, and an output side connected to the output terminal 10d. The semiconductor switch IPD2 has an input side connected to the power supply line 42, and an output side connected to the output terminal 10e. The semiconductor switch IPD3 has an input side connected to the power supply line 42, and an output side connected to the output terminal 10f. The semiconductor switch IPD4 has an input side connected to the power supply input terminal 10b via the power supply line 43, and an output side connected to the output terminal 10g.

[0041] The zone ECU 10 also includes a bypass circuit 14. This bypass circuit 14 has a function of enabling a minimum necessary source power to be supplied to the important load 33 even when the semiconductor switch IPD3 is off. In other words, it is necessary to enable a constant supply of power to the power terminal 33a of the important load 33, but since the source power can be supplied to the important load 33 by utilizing the bypass path formed by the bypass circuit 14, it becomes possible to turn off the semiconductor switch IPD3. By turning off the semiconductor switch IPD3, it becomes possible to reduce the dark current consumed by the zone ECU 10.

[0042] In addition, the semiconductor switch IPD3 consumes a current of several mA to several tens of mA internally when it is on, which causes an increase in dark current when it is always on. Similarly, the DC / DC converter 11 consumes a current of several mA to several tens of mA internally when it is operating, which also causes an increase in dark current when it is always on.

[0043] 1 forms a series circuit composed of a resistor 14a and a diode D1. The input side of the bypass circuit 14 is connected to the power supply input terminal 10b via a power supply line 43, and the output side of the bypass circuit 14 is connected to the output terminal 10f via a power supply line 44.

[0044] The resistor 14a has a function of limiting the current flowing to the important load 33 side via the bypass path of the bypass circuit 14. Specifically, the resistance value of the resistor 14a is determined so as to allow the passage of the minimum necessary power supply current required for the important load 33 to execute the minimum communication function. For example, if a current of a predetermined value or more flows to the load side via this bypass path, the voltage drop of the resistor 14a increases, and further power supply is suppressed. Therefore, consumption of the power stored in the sub-battery 23 can be suppressed.

[0045] The diode D1 has the function of passing a current through the bypass path when necessary and preventing a reverse current flow. That is, when the semiconductor switch IPD3 is turned off, a power supply current flows from the power supply line 43 through the diode D1 in a direction from the output terminal 10f to the important load 33. When the semiconductor switch IPD3 is turned on, the current flowing from the power supply line 43 to the bypass path becomes zero, and the reverse current flow is also blocked by the diode D1.

[0046] In such a power supply device 100, when the vehicle ignition is on, each of the semiconductor switches IPD1 to IPD4 can be turned on as necessary, and the DC / DC converter 11 is in a constantly operating state. Therefore, the power supply device 100 can supply power with a voltage of 48 [V] from the power supply input terminal 10a to the output terminal 10d via the power supply line 41 and the semiconductor switch IPD1. Also, power with a voltage of 12 [V] can be supplied from the output of the DC / DC converter 11 to the output terminal 10e via the power supply line 42 and the semiconductor switch IPD2. Also, power with a voltage of 12 [V] can be supplied from the output of the DC / DC converter 11 to the output terminal 10f via the power supply line 42 and the semiconductor switch IPD3. Also, power with a voltage of 12 [V] can be supplied to the output terminal 10g via the power supply input terminal 10b, the power supply line 43, and the semiconductor switch IPD4.

[0047] On the other hand, when the vehicle ignition is off, the semiconductor switches IPD1, IPD2, and IPD4 are turned off unless otherwise specified, and power supply to the output terminals 10d, 10e, and 10g is stopped. Also, the on / off of the DC / DC converter 11 and the on / off of the semiconductor switch IPD3 are automatically switched on and off according to the operation mode of the power saving function. That is, when the zone ECU 10 enters a sleep state under the control of the microcomputer 13, the operation of the DC / DC converter 11 is stopped and the semiconductor switch IPD3 is turned off, so that the dark current consumed inside the zone ECU 10 is reduced.

[0048] Even in this sleep state, since the bypass path of the bypass circuit 14 shown in FIG. 1 exists, the minimum supply of power from the power source to the power source terminal 33a of the important load 33 can be maintained.

[0049] Furthermore, even when the vehicle ignition is off, when the microcomputer 13 wakes up from the sleep state, the DC / DC converter 11 is turned on and the semiconductor switch IPD3 is also turned on. This makes it possible to operate the important load 33 without limiting the power supply current. When the operation of the important load 33 ends, the microcomputer 13 transitions to the sleep state again, so that the DC / DC converter 11 is turned off and the semiconductor switch IPD3 is also turned off. This makes it possible to reduce the dark current equivalent to the current consumed by the DC / DC converter 11 and the semiconductor switch IPD3 when the vehicle ignition is off.

[0050] Fig. 2 is a flowchart showing an example of control for state transition of the zone ECU 10 shown in Fig. 1. For example, when the microcomputer 13 of the zone ECU 10 is in a sleep state, such as when the ignition of the vehicle is off, the control shown in Fig. 2 is performed. The contents of the control shown in Fig. 2 will be described below.

[0051] Even if the microcomputer 13 itself is in a sleep state, it monitors the state of the built-in communication interface, for example, by a process that is executed periodically (S11). Also, even if the zone ECU 10 is in a sleep state, the important load 33 can always use the communication function by the power supply power supplied to the important load 33 via the bypass circuit 14 of the zone ECU 10. Therefore, when the important load 33 is about to start operation, a signal output by the communication circuit on the important load 33 side appears on the communication bus 29.

[0052] The microcomputer 13 automatically detects whether the important load 33 is about to start operation by determining in S11 whether the state of the communication bus (BUS) 29 is busy. If the state of the communication bus 29 is busy, the process proceeds from S11 to S12.

[0053] The microcomputer 13 wakes up its own operation from a sleep state in S12 and transitions to a normal operation state, and also controls the entire zone ECU 10 to wake up. That is, it starts up the DC / DC converter 11 and switches on the semiconductor switch IPD3. This allows the important load 33 to operate normally without being subject to restrictions on the power supply current.

[0054] In addition, the microcomputer 13 performs control in the normal operation mode in the next step S13. For example, communication is performed between the zone ECU 10 and the important load 33, etc., using a communication interface and a communication bus 29 built into the microcomputer 13. In addition, the microcomputer 13 individually controls the on / off of each of the semiconductor switches IPD1, IPD2, and IPD4 as necessary.

[0055] The microcomputer 13 monitors the state of the communication bus 29 using the built-in communication interface, and repeats the processes of S13 and S14 until it receives a sleep transition command from the important load 33 or another higher-level ECU. Then, when the microcomputer 13 receives the sleep transition command and detects in S14 that the communication bus 29 has been turned off (the bus has been released), it proceeds to the next step S15.

[0056] In S15, the microcomputer 13 puts the zone ECU 10 into a sleep state, and the microcomputer 13 itself also puts itself into a sleep state. That is, all of the semiconductor switches IPD1 to IPD4 are turned off, and the operation of the DC / DC converter 11 is turned off. As a result, the dark current consumed by the zone ECU 10 becomes very small, but it is possible to supply the minimum necessary power supply to the power supply terminal 33a of the important load 33 via the bypass circuit 14.

[0057] Fig. 3 is a block diagram showing a configuration example-2 of a power supply device 100A according to an embodiment of the present invention. The power supply device 100A shown in Fig. 3 is a modified example of the power supply device 100 in Fig. 1. In Fig. 3, components common to the power supply device 100 in Fig. 1 are denoted by the same reference numerals. Description of these common components will be omitted below.

[0058] 3, the output voltage of the main battery 21A that supplies power to the zone ECU 10A is 12 V. Therefore, the voltage that the alternator 22 outputs to the power supply line 27 is also 12 V.

[0059] In addition, since a voltage of 12 V is supplied to the power input terminal 10a of the zone ECU 10A, the zone ECU 10A does not include an element equivalent to the DC / DC converter 11 in Fig. 1. In addition, the load 31A connected to the output terminal 10d of the zone ECU 10A has been modified to operate at a voltage of 12 V.

[0060] Further, the bypass circuit 14A provided in the zone ECU 10A has an input side connected to the power supply line 41 and an output side connected to the power supply line 44. Note that the input side of the bypass circuit 14A may be connected to the power supply line 43, similarly to the zone ECU 10.

[0061] Therefore, the power supply device 100A shown in Fig. 3 can operate in almost the same manner as the power supply device 100 in Fig. 1. However, since the voltage output by the main battery 21A is lower than that of the power supply device 100 in Fig. 1, it is expected that the current flowing through the power supply lines 27, 41, etc. will increase, resulting in increased power loss. Therefore, in the power supply device 100A shown in Fig. 3, for example, the components such as the wires and terminals of the wire harness corresponding to the power supply lines 27, 41, etc. are made thicker and larger.

[0062] Fig. 4 is a block diagram showing a third configuration example of a power supply device 100B according to an embodiment of the present invention. The power supply device 100B shown in Fig. 4 is a modified example of the power supply device 100 in Fig. 1. In Fig. 4, components common to the power supply device 100 in Fig. 1 are denoted by the same reference numerals. Descriptions of these common components will be omitted below.

[0063] The zone ECU 10B shown in Fig. 4 includes a bypass circuit 14B. The bypass circuit 14B also includes a resistor Rs and a diode D1 connected in series. The resistor Rs has a function of detecting the magnitude of a current passing through the bypass path of the bypass circuit 14B.

[0064] The zone ECU 10B also includes a current detection circuit 15 connected to both ends of the resistor Rs. The current detection circuit 15 includes an amplifier that amplifies the potential difference between the terminals of the resistor Rs. A signal output from the current detection circuit 15 is input to the control unit 12A and the microcomputer 13A.

[0065] The control unit 12A can individually control the on / off of each of the semiconductor switches IPD1 to IPD4 according to a control signal output from the microcomputer 13A. In addition, the control unit 12A can switch on the semiconductor switch IPD3 according to a signal output from the current detection circuit 15 when the current flowing through the resistor Rs becomes equal to or greater than a predetermined threshold value.

[0066] The microcomputer 13A monitors the level of the signal output by the current detection circuit 15 and the state of the communication bus 29, and can control the DC / DC converter 11 and the control unit 12A so as to reflect the monitoring results.

[0067] As for the important load 33 shown in FIG. 4, the communication terminal 33c may be connected to the communication bus 29 as in the configuration of FIG. 1, but even if the important load 33 does not have a communication function, the important load 33 can be connected to the zone ECU 10B in FIG. 4.

[0068] Fig. 5 is a flowchart showing an example of control for state transition of the zone ECU 10B shown in Fig. 4. For example, when the microcomputer 13A of the zone ECU 10B is in a sleep state, such as when the ignition of the vehicle is off, the control shown in Fig. 5 is performed. The contents of the control shown in Fig. 5 will be described below.

[0069] Even if the microcomputer 13A itself is in a sleep state, it monitors the level of the output signal from the current detection circuit 15 and the state of the built-in communication interface, for example, by periodically executing a process (S11A, S11B).

[0070] Even if the zone ECU 10B is in the sleep state, the important load 33 can always use the communication function by the power supply power supplied to the important load 33 via the bypass circuit 14B of the zone ECU 10B. Therefore, when the important load 33 is about to start operation, a signal output by the communication circuit on the important load 33 side appears on the communication bus 29.

[0071] When the important load 33 starts an operation such as communication, the current flowing through the resistor Rs of the bypass circuit 14B increases. A signal indicating the magnitude of the current flowing through the resistor Rs is input to the microcomputer 13A via the detection circuit 15.

[0072] Therefore, the microcomputer 13A automatically detects whether or not the important load 33 is about to start operating by monitoring the level of the signal output by the current detection circuit 15 at S11A.

[0073] Furthermore, the microcomputer 13A automatically detects whether the important load 33 is about to start operating by identifying in S11B whether the state of the communication bus (BUS) 29 is busy or not. If a current of a certain level or more is detected flowing through the resistor Rs, the process proceeds from S11A to S12, and if the state of the communication bus 29 is busy, the process proceeds from S11B to S12.

[0074] The processes from S12 onward in Fig. 5 are the same as the processes S12 to S15 already described in Fig. 2. Therefore, the microcomputer 13A and the zone ECU 10B can automatically wake up from the sleep state and transition to a normal operation state, or can transition from the normal operation state back to the sleep state.

[0075] Fig. 6 is a block diagram showing a fourth configuration example of a power supply device 100C according to an embodiment of the present invention. The power supply device 100C shown in Fig. 6 is a modified example of the power supply device 100B in Fig. 4. In Fig. 6, components common to the power supply device 100B in Fig. 4 are denoted by the same reference numerals. The following description of these common components will be omitted.

[0076] 6, the output voltage of the main battery 21A that supplies power to the zone ECU 10C is 12 V. Therefore, the voltage that the alternator 22 outputs to the power supply line 27 is also 12 V.

[0077] In addition, since a voltage of 12 V is supplied to the power input terminal 10 a of the zone ECU 10C, the zone ECU 10C does not include an element equivalent to the DC / DC converter 11 in Fig. 4. In addition, the load 31A connected to the output terminal 10 d of the zone ECU 10C has been modified to operate at a voltage of 12 V.

[0078] Further, the bypass circuit 14C provided in the zone ECU 10C has an input side connected to the power supply line 41 and an output side connected to the power supply line 44. The input side of the bypass circuit 14C may be connected to the power supply line 43, similarly to the zone ECU 10B.

[0079] Therefore, the power supply device 100C shown in Fig. 6 can operate in almost the same manner as the power supply device 100B shown in Fig. 4. However, since the voltage output by the main battery 21A is lower than that of the power supply device 100B shown in Fig. 4, it is expected that the current flowing through the power supply lines 27, 41, etc. will increase, resulting in increased power loss. Therefore, in the case of the power supply device 100C shown in Fig. 6, for example, the components such as the wires and terminals of the wire harness corresponding to the power supply lines 27, 41, etc. will be made thicker and larger.

[0080] Fig. 7 is a block diagram showing a fifth configuration example of a power supply device 100D according to an embodiment of the present invention. The power supply device 100D shown in Fig. 7 is a modified example of the power supply device 100B in Fig. 4. In Fig. 7, components common to the power supply device 100B in Fig. 4 are denoted by the same reference numerals. The following description of these common components will be omitted.

[0081] 7 includes a plurality of zone ECUs 10D and 10E that are independent of each other. The configuration of the zone ECU 10D is substantially the same as that of the above-mentioned zone ECU 10B.

[0082] As shown in FIG. 7, the zone ECU 10E includes a DC / DC converter 11A, a microcomputer 13B, and a semiconductor switch IPD4.

[0083] A power input terminal 10i of the zone ECU 10E is connected to the output of the main battery 21 via a power line 27A and fuses 25A and 24. A communication terminal 10j of the zone ECU 10E is connected to a communication bus 29. An output terminal 10h of the zone ECU 10E is connected to a power terminal 33b of the important load 33 via a power line 52A.

[0084] The zone ECU 10E can step down the 48V power supply supplied from the main battery 21 to 12V using the internal DC / DC converter 11A, so that the 12V power supply can be supplied from the output terminal 10h to the power supply terminal 33b of the important load 33.

[0085] 7, the zone ECU 10D also has a built-in bypass circuit 14B, so when the semiconductor switch IPD3 is in the off state, the bypass path passing through the resistor Rs can be used to constantly supply power from the power source to the power source terminal 33a of the important load 33. In addition, in the sleep state, the DC / DC converter 11A and the semiconductor switch IPD3 in the zone ECU 10D can be controlled to be turned off, so that the dark current consumed in the zone ECU 10D can be reduced.

[0086] As described above, in any of the power supply devices 100, 100A, 100B, 100C, and 100D, the power supply can be supplied to the important load 33 that requires a constant supply of power from the power supply by utilizing the bypass path of the bypass circuit 14, 14A, 14B, or 14C. Therefore, the current flowing through the semiconductor switch IPD3 can be switched off to reduce the dark current consumed by the semiconductor switch IPD3. In addition, the dark current consumed by the DC / DC converter 11 can be reduced by stopping the operation of the DC / DC converter 11.

[0087] The important load 33 needs to be operated reliably when necessary, but the time when the important load 33 actually needs to function (e.g., brake) and consumes power from the power source is usually limited to a relatively short time. Therefore, reducing the dark current flowing to the zone ECU 10 side when the important load 33 is not operating is very effective in preventing the main battery 21 or the sub-battery 23 from running down or deteriorating due to unnecessary consumption.

[0088] 2 or 5, it is possible to automatically switch between the sleep state and the normal operation state of the zone ECU 10. Therefore, it is possible to efficiently reduce the dark current.

[0089] In addition, since the power supply device 100 and the like are provided with multiple systems such as the main battery 21 and the sub-battery 23 as on-board power sources, if a failure such as a disconnection or battery removal occurs in one power source system, the other power source system can be used as a backup. Therefore, the function of the important load 33 can be constantly maintained.

[0090] The present invention is not limited to the above-described embodiment, and can be appropriately modified, improved, etc. In addition, the material, shape, size, number, arrangement location, etc. of each component in the above-described embodiment are arbitrary as long as the present invention can be achieved, and are not limited.

[0091] For example, in the above embodiment, it is assumed that the bypass circuit 14 is mounted inside the zone ECU 10, but a similar bypass circuit 14 may be mounted in another ECU.

[0092] Here, the features of the in-vehicle power supply device according to the embodiment of the present invention described above will be briefly summarized and listed in the following [1] to [6]. [1] An on-board power supply device (power supply device 100) that supplies power from a first on-board power source (main battery 21) or a second on-board power source (sub-battery 23) to a predetermined important load (33) on a vehicle that constantly requires a power supply from a power source, a main power supply unit (power supply line 44) that supplies the output power of the first vehicle power supply to the input side of the important load through a main path via a main semiconductor switch (IPD3); a sub-power supply unit (power supply line 43) that supplies the output power of the second vehicle power supply to the input side of the important load through a sub-path that passes through a sub semiconductor switch (IPD4); a bypass power supply unit (bypass circuit 14) that supplies output power of the first vehicle power supply or the second vehicle power supply to an input side of the important load through a bypass path that bypasses at least the main semiconductor switch and the sub semiconductor switch; An in-vehicle power supply device comprising:

[0093] [2] A control unit (12) for controlling the main semiconductor switch, The control unit is In a predetermined standby state, the main semiconductor switch is controlled to be turned off (S15), and when communication is received from at least the important load side, the state transitions to wake-up (S11), and the main semiconductor switch is controlled to be turned on (S12). The vehicle-mounted power supply device according to [1] above.

[0094] [3] The bypass path (bypass circuit 14) has a current suppression unit (resistor 14a) that suppresses the current flowing downstream of the bypass path (bypass circuit 14). An in-vehicle power supply device according to the above [1] or [2].

[0095] [4] An input side of the bypass power supply unit is connected to an output of the second vehicle power supply (see FIG. 1 ); The in-vehicle power supply device according to any one of the above [1] to [3].

[0096] [5] A first output voltage (48 [V]) output by the first vehicle power supply is higher than a second output voltage (12 [V]) output by the second vehicle power supply, a voltage conversion unit (DC / DC converter 11) that steps down the first output voltage to a voltage close to the second output voltage; the voltage conversion unit is connected to an output side of the first vehicle power supply, The main semiconductor switch is connected to an output side of the voltage conversion unit. The vehicle-mounted power supply device according to [4] above.

[0097] [6] An on-board power supply device that supplies power from one or more on-board power sources to a specified important load that requires a constant supply of power from a power source on a vehicle, a main power supply unit that supplies output power of the on-board power supply to an input side of the important load through a main path via a semiconductor switch; a bypass power supply unit that supplies an output power of the on-board power supply to an input side of the important load through a bypass path that bypasses at least the semiconductor switch; An in-vehicle power supply device comprising: [Explanation of symbols]

[0098] 10, 10A, 10B, 10C, 10D, 10E Zone ECU 10a, 10b Power input terminals 10c Communication terminal 10d, 10e, 10f, 10g output terminals 11,11A DC / DC converter 12, 12A Control section 13, 13A, 13B Microcomputers 14, 14A, 14B, 14C Bypass circuit 14a resistor 15 Current detection circuit 21,21A Main Battery 22 Alternator 23 Sub battery 24, 25, 26 Fuse 27, 27A, 28 Power lines 29 Communication Bus 31,31A,32 load 33 Important load 33a,33b Power terminal 33c Communication terminal 41, 42, 43, 44 Power lines 51,52 Power lines 100,100A,100B,100C,100D power supply equipment D1 Diode IPD1, IPD2, IPD3, IPD4 Semiconductor switches Rs Resistor

Claims

1. An on-board power supply device that supplies source power from a first on-board power source or a second on-board power source to a predetermined important load that constantly requires a supply of source power on a vehicle, the critical load having a first power terminal and a second power terminal; a main power supply unit that supplies output power of the first vehicle power supply to the first power supply terminal of the important load through a main path via a main semiconductor switch; a sub-power supply unit that supplies output power of the second on-board power supply to the second power supply terminal of the important load through a sub-path that passes through a sub semiconductor switch; a bypass power supply unit that supplies an output power of the first vehicle power supply or the second vehicle power supply to the first power supply terminal of the important load through a bypass path that bypasses at least the main semiconductor switch and the sub semiconductor switch; An in-vehicle power supply device comprising:

2. An on-board power supply device that supplies power from a first on-board power source or a second on-board power source to a predetermined important load that requires a constant supply of power on a vehicle, a main power supply unit that supplies an output power of the first vehicle power supply to an input side of the important load through a main path via a main semiconductor switch; a sub-power supply unit that supplies an output power of the second vehicle power supply to an input side of the important load through a sub-path that passes through a sub-semiconductor switch; a bypass power supply unit that supplies output power of the first vehicle power supply or the second vehicle power supply to an input side of the important load through a bypass path that bypasses at least the main semiconductor switch and the sub semiconductor switch; Equipped with a control unit for controlling the main semiconductor switch, The control unit is In a predetermined standby state, the main semiconductor switch is controlled to be off, and when communication is received from at least the important load side, the wake-up state is transitioned to and the main semiconductor switch is controlled to be on. On-vehicle power supply device.

3. The bypass path has a current suppression unit that suppresses a current flowing downstream thereof.

3. An in-vehicle power supply device according to claim 1 or 2.

4. an input side of the bypass power supply unit is connected to an output side of the second vehicle power supply; The vehicle-mounted power supply device according to any one of claims 1 to 3.

5. a first output voltage output by the first vehicle-mounted power supply is higher than a second output voltage output by the second vehicle-mounted power supply; a voltage conversion unit that reduces the first output voltage to a voltage close to the second output voltage; the voltage conversion unit is connected to an output side of the first vehicle power supply, The main semiconductor switch is connected to an output side of the voltage conversion unit.

5. An on-board power supply device according to claim 4.

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