Current detection device and power supply device

Abstract

A current detection device includes a sensing resistor through which a sensing current corresponding to a consumption current supplied to a load flows, and an A / D converter configured to perform A / D conversion in accordance with a voltage drop generated by the sensing current flowing through the sensing resistor to detect the consumption current. A resistance value of the sensing resistor is set to be variable.

Description

Technical Field

[0001] This disclosure relates to a current detection device and a power supply device. Background Technology

[0002] In the prior art, a current detection device is known that detects the current consumed by a battery installed in a vehicle, supplied to a load. As a current detection device, an induced current corresponding to the consumed current flows through an inductive resistor, and the voltage drop generated in the inductive resistor is converted by an analog-to-digital converter (A / D converter) to detect the voltage.

[0003] In recent years, to address CASE (Connected, Autonomous, Shared / Services, and Electric) and Maas (Mobility as a Service) paradigms, vehicle specifications have increased, as have the types of loads installed on vehicles. For example, even with the same lamp load, there may be a headlight consuming 0.5A and an external lamp consuming 1.0A. Therefore, in order to detect the current of both the headlight consuming 0.5A and the external lamp consuming 1.0A, it is necessary to use an A / D converter with a wide dynamic range.

[0004] However, when using an A / D converter with a wide dynamic range, the current sensing accuracy decreases when the current consumption is low. Therefore, in the prior art, A / D converters with a dynamic range corresponding to the load's current consumption are used. However, in this case, the types of current sensing devices may increase.

[0005] Furthermore, it is considered that the resistor in the on / off detection circuit used to detect the conduction and opening of the contact switch is variable (JP-A-2012-138835). However, in JP-A-2012-138835, the variable resistor is not a resistor for detecting the current flowing through the load.

[0006] The present invention was made in view of the above circumstances, and its object is to provide a current detection device and power supply device that can reduce the number of component types. Summary of the Invention

[0007] To achieve the above objectives, the current detection device and power supply device according to this disclosure are characterized as follows.

[0008] According to an aspect of this disclosure, a current detection device is provided, comprising: a sensing resistor through which an induced current corresponding to a consumed current supplied to a load flows; and an A / D converter configured to perform A / D conversion on a voltage drop generated by the induced current flowing through the sensing resistor to detect the consumed current, wherein the resistance value of the sensing resistor is set to be variable.

[0009] Furthermore, according to another aspect of this disclosure, a power supply device is provided, comprising: the current detection device; a semiconductor switching element configured to turn on and off the consumed current supplied to the load; an overheat detection unit configured to detect overheating of a wire through which the consumed current flows based on the consumed current detected by the A / D converter; and a switch control unit configured to disconnect the semiconductor switching element if the overheat detection unit detects the overheating.

[0010] This disclosure can provide a current sensing device and a power supply device that can reduce the number of component types.

[0011] The present disclosure has been briefly described above. The details of the present disclosure will be further explained by reading the accompanying drawings, which illustrate the modes for implementing the present disclosure (hereinafter referred to as "Embodiments"). Attached Figure Description

[0012] Figure 1 This is a block diagram illustrating an embodiment of a communication system that includes a regional ECU as a power supply device, according to this embodiment.

[0013] Figure 2 It shows Figure 1 The circuit diagram shown illustrates the structure of the ECU in the area shown.

[0014] Figure 3 This is a circuit diagram showing the loads installed on each of the vehicle's A, B, and regional ECUs.

[0015] Figure 4 It shows through Figure 2 The flowchart shows the overheat prevention process executed by the CPU of the ECU in the shown area. Detailed Implementation

[0016] Specific embodiments according to this disclosure will now be described with reference to the accompanying drawings.

[0017] Figure 1 This is a block diagram illustrating a communication system 1 according to this embodiment, which includes a regional ECU serving as a power supply device. The communication system 1 according to this embodiment is installed in a vehicle. The communication system 1 includes a central electronic control unit (ECU) 2 and a regional ECU 3 serving as both a current detection device and a power supply device.

[0018] The central ECU2 includes a central processing unit (CPU) that operates according to a program and is located in a device such as the vehicle's dashboard. The central ECU2 controls the entire communication system 1.

[0019] The regional ECU3 is located in each region of the vehicle, such as the left and right doors and the roof. The regional ECU3 communicates with the central ECU2 and controls the power supply to the loads 4 arranged in that region according to the instructions from the central ECU2.

[0020] like Figure 2 As shown, the region ECU3 includes a semiconductor field-effect transistor (FET) 31 that acts as a semiconductor switching element to turn on and off the power supply to the load 4, a sensing resistor 32 through which a sensing current Is corresponding to the consumed current supplied to the load 4 flows, and a CPU 33 that constructs an A / D converter 33a and operates according to a program.

[0021] A power supply (not shown) and a load 4 are connected between the drain and source of semiconductor FET 31, and semiconductor FET 31 turns on and off to supply power to load 4. Although only one semiconductor FET 31 is configured... Figure 2 In the example shown, multiple semiconductor FETs 31 can also be configured.

[0022] Load 4, with different current consumption depending on the vehicle's specifications, is connected to semiconductor FET 31. For example... Figure 3 As shown, in vehicle A, a lighting lamp with a current consumption of 0.5A is connected as a load 4 to the semiconductor FET 31. In vehicle B, an external lamp with a current consumption of 1.0A is connected as a load 4 to the semiconductor FET 31. The wire L connecting the semiconductor FET 31 and the load 4 is a wire with a thickness corresponding to the current consumption supplied to the load 4. For example, when the lighting lamp with a current consumption of 0.5A is connected as the load 4, a wire L with a smaller diameter of 0.13 square millimeters is used. On the other hand, when the external lamp with a current consumption of 1.0A is connected as the load 4, a wire L with a larger diameter of 1.25 square millimeters is used.

[0023] The semiconductor FET 31 according to this embodiment has a so-called current sensing function and includes a built-in main FET (not shown) that supplies power to the load 4 and a built-in sensing FET (not shown) that detects the consumed current supplied to the load 4. The gate and drain of the sensing FET are commonly connected to the gate and drain of the main FET, respectively, and the current corresponding to the current flowing through the main FET (=consumed current) flows as the sensing current Is of the sensing FET. Figure 2 As shown, the semiconductor FET 31 is provided with a sensing electrode 31a, which serves as the output terminal for the output sensing current Is. The gate of the semiconductor FET 31 is connected to the CPU 33, which controls the on and off states of the semiconductor FET 31.

[0024] The sensing resistor 32 is disposed between the sensing electrode 31a and ground, and has a variable resistance value. In this embodiment, the sensing resistor 32 includes a plurality of resistors Rs1, Rs2, and Rs3 connected in parallel, and switches S1, S2, and S3 connected in parallel to the plurality of resistors Rs1, Rs2, and Rs3 respectively in series. Resistors Rs1, Rs2, and Rs3 may have different resistance values, or all or part of resistors Rs1, Rs2, and Rs3 may have the same resistance value.

[0025] One end of resistors Rs1, Rs2, and Rs3 is grounded, and the other ends of resistors Rs1, Rs2, and Rs3 are connected to switches S1, S2, and S3, respectively. One end of switches S1, S2, and S3 is connected to sensing electrode 31a, and the other ends of switches S1, S2, and S3 are connected to resistors Rs1, Rs2, and Rs3, respectively. The resistance value of sensing resistor 32 can be changed by combining the on and off states of switches S1, S2, and S3. Switches S1, S2, and S3 are connected to CPU 33, which controls the on and off states of switches S1, S2, and S3.

[0026] The voltage drop (voltage) generated by the induced current Is flowing through the sensing resistor 32 is input to the A / D converter 33a via resistor R2 as the current consumption information Vs. The A / D converter 33a performs A / D conversion on the current consumption information Vs to detect the current consumption.

[0027] Next, the operation of the communication system 1 with the above-described structure will be described. When the ignition switch is turned on, the CPU 33 of the zone ECU 3 begins to communicate with the central ECU 2 and controls the switching on and off of the semiconductor FET 31 according to instructions from the central ECU 2. In parallel with this, the zone ECU 3 executes... Figure 4 The overheat prevention measures shown are as follows.

[0028] When the ignition switch is turned on, the CPU 33 reads the wire information stored in the memory (not shown) and turns switches S1 to S3 (Sp1) on and off according to the read wire information. The wire information includes information related to the thickness (size) of the wire L. Therefore, the resistance value can be set according to the thickness of the wire L, that is, the current consumed flowing through the wire L. Specifically, the CPU 33 turns switches S1 to S3 on and off such that the combined resistance value of the sensing resistor 32 decreases as the wire L becomes thicker and the current consumed increases, and turns switches S1 to S3 off such that the combined resistance value of the sensing resistor 32 increases as the wire L becomes thinner and the current consumed decreases.

[0029] Next, CPU 33 receives the current consumption information Vs converted by A / D converter 33a and detects the current consumption (Sp2). Then, CPU 33 acts as an overheat detection unit, calculating the heat generated by wire L based on the detected current consumption and detecting overheating of wire L (Sp3). When overheating is detected (Yes in Sp3), CPU 33 acts as a switch control unit, disconnecting semiconductor FET 31 to cut off the current consumption flowing through wire L (Sp4) and ending the process. Conversely, if no overheating is detected (No in Sp3), CPU 33 returns to Sp2.

[0030] A reprogramming device (external device, not shown) capable of rewriting the programs and data stored in the memories of the central ECU2 and the regional ECU3 is detachably connected to the communication system 1. The central ECU2 communicates with the reprogramming device to rewrite its own programs and data, or to instruct the rewriting of the programs and data of the regional ECU3. The wiring information stored in the aforementioned regional ECU3 can be rewritten through communication with the reprogramming device (external). That is, the CPU 33 of the regional ECU3 functions as a setting unit and can set the resistance value of the sensing resistor 32 to a resistance value according to the communication with the reprogramming device.

[0031] In the example above, the regional ECU3 communicates with the reprogramming device via the central ECU2, but the regional ECU3 and the reprogramming device can communicate directly with each other. The reprogramming device can be connected to the communication system 1 via wired or wireless means.

[0032] According to the above embodiment, the resistance value of the sensing resistor 32 is set to be variable. Therefore, the sensing resistor 32 can be set to a resistance value corresponding to the current consumption of the load 4, and the current consumption can be accurately detected even if the load 4 is replaced according to specifications, etc. That is, even if a lighting lamp with a current consumption of 0.5A is connected as the load 4, or an external lamp with a current consumption of 1.0A is connected as the load 4, the voltage range of the current consumption information Vs can be set to be approximately the same, and it is not necessary to replace the A / D converter 33a of the area ECU3 for each load current. Therefore, the number of types of area ECU3 can be reduced. Development processing due to the replacement of the load 4 can be reduced, and the cost of the area ECU3 due to its mass and volume can be reduced.

[0033] According to the above embodiment, the CPU 33 of the region ECU 3 rewrites the wiring information through communication with the reprogramming device and sets the resistance value of the sensing resistor 32 to a value based on the communication. Therefore, the resistance value of the sensing resistor 32 can be set through communication with the reprogramming device.

[0034] According to the above embodiment, the sensing resistor 32 includes a plurality of resistors Rs1, Rs2, and Rs3 connected in parallel, and switches S1, S2, and S3 respectively connected to Rs1, Rs2, and Rs3. Therefore, the sensing resistor 32 can be variably configured with a simple structure.

[0035] According to the above embodiment, the CPU 33 detects overheating of the wire L based on the current consumption detected by the A / D converter 33a, and disconnects the semiconductor FET 31 when overheating is detected. Therefore, overheating of the wire L can be prevented.

[0036] According to the above embodiment, the semiconductor FET 31 includes a sensing electrode 31a that outputs a sensed current Is, and the sensed current Is output from the sensing electrode 31a flows through a sensing resistor 32. Therefore, the sensed current Is can flow through the sensing resistor 32 with a simple construction.

[0037] This disclosure is not limited to the above embodiments, and modifications and improvements can be made as appropriate. Furthermore, as long as the present invention can be implemented, the material, shape, size, quantity, and arrangement of the components in the above embodiments are optional and not limited.

[0038] According to the above embodiment, the CPU 33 is configured to rewrite wire information based on communication with the reprogramming device and set the resistance value of the sensing resistor 32 based on the rewritten wire information, but this disclosure is not limited thereto. For example, an operating switch can be provided in the region ECU 3, and the CPU 33 can set the resistance value of the sensing resistor 32 based on the on and off information of the operating switch.

[0039] According to the above embodiment, a semiconductor FET 31 with current sensing function is used, but this disclosure is not limited thereto. A circuit for dividing the current consumption flowing through the wire L can be provided, and the induced current Is flowing through the dividing circuit can flow through the sensing resistor 32.

[0040] Here, the features of the embodiments of the current detection device and power supply device of the present disclosure described above will be briefly summarized and listed in [1] to [5] below.

[0041] [1]. A current detection device (3), comprising:

[0042] The sensing resistor (32) through which an induced current (Is) flows, corresponding to the consumed current supplied to the load (4); and

[0043] An A / D converter (33a) is configured to perform A / D conversion on the voltage drop generated by the induced current (Is) flowing through the induced resistor (32) to detect the consumed current.

[0044] The resistance value of the sensing resistor (32) is set to be variable.

[0045] [2]. The current detection device (3) according to [1] further includes:

[0046] The setting unit (33) is configured to set the resistance value of the sensing resistor (32) to a resistance value corresponding to communication with an external device.

[0047] [3]. According to the current detection device (3) described in [1] or [2],

[0048] The sensing resistor (32) includes: a plurality of resistors (Rs1 to Rs3) connected in parallel; and switches (S1 to S3) connected in series with the plurality of resistors (Rs1 to Rs3) and connected in parallel with each other.

[0049] [4]. A power supply device (3), comprising:

[0050] The current detection device (3) according to any one of [1]-[3];

[0051] A semiconductor switching element (31) is configured to turn on and off the current consumed by the load (4);

[0052] An overheat detection unit (33) is configured to detect overheating of a wire through which the current-consuming wire flows based on the current-consuming current detected by the A / D converter (33a); and

[0053] A switch control unit (33) is configured to disconnect the semiconductor switch element (31) in the event that the overheating is detected by the overheating detection unit (33).

[0054] [5]. According to the power supply device (3) described in [4],

[0055] The semiconductor switching element (31) has an output terminal (31a) for outputting the induced current (Is), and

[0056] The induced current (Is) output from the output terminal (31a) flows through the induced resistor (32).

[0057] According to the current sensing device with structure [1], the resistance value of the sensing resistor is set to be variable. Therefore, the resistance value of the sensing resistor can be set according to the current consumed by the load, and the voltage drop range of the sensing resistor can be kept approximately the same even if the load is changed, and it is not necessary to replace the A / D converter for each load current, and the number of component types can be reduced.

[0058] According to the current detection device with structure [2], the resistance value of the sensing resistor can be set according to communication with an external device. Therefore, the resistance value of the sensing resistor can be easily changed according to the current consumption.

[0059] According to the current detection device with structure [3], the resistance value of the sensing resistor can be variably set by a simple structure.

[0060] According to the power supply device with structure [4], overheating of the wires can be prevented.

[0061] According to the power supply device with the structure [5], the induced current corresponding to the consumed current can flow through the induced resistor through a simple structure.

Claims

1. A current detection device, comprising: An induced resistor through which an induced current flows, corresponding to the current consumed by the load; An A / D converter configured to perform A / D conversion on the voltage drop generated by the induced current flowing through the sensing resistor, to detect the consumed current; and, The setting unit is configured to read the size information of the wire flowing through the current-consuming wire stored in the memory, and set the resistance value of the sensing resistor to a resistance value corresponding to the size information. Wherein, the resistance value of the sensing resistor is set to be variable; The sensing resistor includes multiple resistors connected in parallel and multiple switches connected in parallel to each other and connected in series with the multiple resistors respectively. The multiple resistors and the multiple switches are all connected to the same load. The setting unit is configured to, based on the size information of the wire, turn each of the plurality of switches on or off, such that the resistance value of the sensing resistor decreases as the wire becomes thicker and the current consumption increases, or that the resistance value of the sensing resistor increases as the wire becomes thinner and the current consumption decreases; and The dimensional information of the wire is configured to be rewritten through communication with an external reprogramming device.

2. The current detection device according to claim 1, The setting unit is configured to set the resistance value of the sensing resistor to a resistance value corresponding to communication with an external device.

3. A power supply device, comprising: The current detection device according to claim 1 or 2; A semiconductor switching element configured to turn on and off the current consumed by the load; An overheat detection unit is configured to detect overheating of a wire through which the current is flowing, based on the current consumed by the A / D converter. as well as A switch control unit is configured to disconnect the semiconductor switching element when the overheating is detected by the overheating detection unit.

4. The power supply device according to claim 3, in, The semiconductor switching element has an output terminal for outputting the induced current, and The induced current output from the output terminal flows through the induced resistor.

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