Power supply circuit and motor control device

Abstract

The present invention provides a power supply circuit and a motor control device capable of suppressing the complexity of the management of the power supply circuit. A switching unit (70) obtains information corresponding to the type of a torque sensor (50), namely, identification information (I). The switching unit (70) outputs either a reference voltage (Vref) or a power supply voltage (Vcc) as a reference voltage based on the obtained identification information (I). A voltage application unit (60) applies an operating voltage (Vt) corresponding to the type of the torque sensor (50) to the torque sensor (50) based on the power supply voltage (Vcc) or the reference voltage (Vref) applied by the switching unit (70) as the reference voltage of the voltage application unit (60).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The disclosure of Japanese Patent Application No. 2018-207657 filed on November 2, 2018 including specification, drawings and abstract is incorporated herein by reference in its entirety. Technical Field

[0003] The invention relates to a power supply circuit and a motor control device. Background Art

[0004] Japanese Patent Publication No. 2009-208504 discloses a torque sensor for detecting steering torque. Such a torque sensor is operated by power supplied from a battery. Specifically, the power supplied from the battery is stepped down to a reference voltage by a reference voltage generating circuit, and an operating voltage for driving the torque sensor is generated by a sensor power supply circuit based on the reference voltage. The operating voltage is applied to the torque sensor by the sensor power supply circuit, so that the torque sensor is operated.

[0005] There are various types of torque sensors, each of which requires a different operating voltage for operation. Therefore, it is necessary to prepare a plurality of sensor power supply circuits corresponding to the types of torque sensors, which makes management of the power supply circuit complicated. Summary of the invention

[0006] One of the objects of the present invention is to provide a power supply circuit and a motor control device capable of suppressing the complexity of management of the power supply circuit.

[0007] A power supply circuit of one embodiment of the present invention comprises: a voltage application unit, which applies an action voltage based on a reference voltage to a sensor, and the sensor outputs an output value based on a detected state quantity; and a switching unit, which switches the reference voltage of the voltage application unit so that it becomes a voltage corresponding to the type of the sensor and required for operating the sensor.

[0008] According to the above configuration, the reference voltage of the voltage applying unit is switched by the switching unit in accordance with the type of the sensor, so that the voltage applying unit can apply an appropriate operating voltage corresponding to the type of the sensor. The operating voltage can be applied in a manner corresponding to the type of the sensor, so the types of power supply circuits prepared in advance can be reduced, and the complexity of the management of the power supply circuit can be suppressed.

[0009] Another embodiment of the present invention is that in the above embodiment, the power supply circuit is connected to the control device, the power supply circuit also has a first reference voltage generating circuit that generates a first reference voltage, one of the sensors is a first sensor that outputs a voltage based on a detected state quantity to the control device, and the switching unit is configured such that when the voltage application unit applies an operating voltage to the first sensor, the first reference voltage generated by the first reference voltage generating circuit and having the same potential as the power supply voltage of the control device generated based on the battery voltage can be selected as the reference voltage of the voltage application unit.

[0010] Another other embodiment of the present invention is that in the above embodiment, the power supply circuit is connected to the control device, the power supply circuit also has a second reference voltage generating circuit that generates a second reference voltage, one of the sensors is a second sensor that outputs the detected state quantity as a digital value, and the switching unit is configured to: when the voltage application unit applies an operating voltage to the second sensor, the second reference voltage generated by the second reference voltage generating circuit according to the battery voltage can be selected as the reference voltage of the voltage application unit.

[0011] For sensors that are the objects of power supply of the power supply circuit, the operating voltage required for operation is sometimes different depending on the type. Therefore, the switching unit is configured to be able to select an appropriate reference voltage as the reference voltage of the voltage application unit according to the type of the sensor. Thus, the voltage application unit can apply an operating voltage corresponding to the first reference voltage and the second reference voltage, that is, an operating voltage corresponding to the type of the sensor, to the sensor. For example, in the case where the voltage application unit applies the operating voltage to the first sensor, the switching unit can select the first reference voltage as the reference voltage. In addition, for example, in the case where the voltage application unit applies the operating voltage to the second sensor, the switching unit can select the second reference voltage as the reference voltage.

[0012] Another embodiment of the present invention provides a motor control device, which comprises the power supply circuit described in the above embodiment and a control device connected to the power supply circuit, wherein when the starting switch of the vehicle is turned on, the control device is powered from the battery, the control device stores identification information corresponding to the type of the sensor, and controls the drive of the motor, and when the starting switch is turned on, the control device outputs the identification information corresponding to the type of the sensor connected to the power supply circuit to the switching unit, and the switching unit switches the reference voltage of the voltage application unit based on the identification information.

[0013] According to the above structure, when the start switch of the vehicle is turned on, the control device outputs identification information corresponding to the type of the sensor connected to the power circuit to the switching unit. As a result, the switching unit can switch the reference voltage of the voltage application unit to the reference voltage corresponding to the type of the sensor based on the identification information, so that the operating voltage to the sensor can be changed corresponding to the type of the sensor. Since the operating voltage can be applied in a manner corresponding to the type of the sensor, the types of power circuits prepared in advance can be reduced, and the complexity of the management of the power circuit can be suppressed.

[0014] Another embodiment of the present invention provides a motor control device, which includes the power supply circuit described in the above embodiment and a control device connected to the power supply circuit, wherein when the starting switch of the vehicle is turned on, the control device is powered from a battery, the control device stores identification information corresponding to the type of the sensor, and controls the drive of the motor, the power supply circuit includes a terminal portion, the terminal portion outputs an identification status for identifying the type of the sensor to the switching portion, and the switching portion switches the reference voltage of the voltage application portion based on the identification status.

[0015] According to the above structure, the switching unit can switch the reference voltage of the voltage applying unit based on the identification state corresponding to the type of sensor. Since the terminal unit for outputting the identification state is provided in the power supply circuit, it is not necessary to provide a structure for outputting the identification state in the control device, and accordingly, the control device can be simply constructed. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other features and advantages of the present invention will become apparent from the following description of embodiments with reference to the accompanying drawings, in which like reference numerals are used to denote like elements, wherein:

[0017] Figure 1 This is a block diagram showing a schematic configuration of a motor control device according to a first embodiment.

[0018] Figure 2 : is a block diagram showing a schematic configuration of a reference voltage generating unit and a power supply voltage generating unit.

[0019] Figure 3 It is a block diagram showing a schematic configuration of a power supply circuit according to the second embodiment. DETAILED DESCRIPTION

[0020] Hereinafter, a motor control device according to a first embodiment of the present invention will be described. Figure 1 The motor control device 1 is schematically shown. Figure 1 In order to simplify the description, illustration of resistors and the like is omitted.

[0021] like Figure 1As shown, the motor control device 1 includes a microcomputer 10 and a power supply circuit 20. The microcomputer 10 is an example of a control device. The microcomputer 10 and the power supply circuit 20 are operated by a battery voltage V supplied from a battery 30. The microcomputer 10 of the motor control device 1 is connected to a motor 40, and controls the operation of the motor 40 based on the outputs of various sensors. As various sensors, for example, a torque sensor 50 is used.

[0022] An ignition switch 31 is provided between the battery 30 and the power supply circuit 20 as a start switch for switching on and off the power supplied from the battery 30. The ignition switch 31 is switched on and off by the driver operating a switch provided in the vehicle. When the ignition switch 31 is on, power is supplied between the battery 30 and the power supply circuit 20 through the ignition switch 31. When the ignition switch 31 is off, power is cut off between the battery 30 and the power supply circuit 20 through the ignition switch 31.

[0023] When power is supplied between the battery 30 and the power supply circuit 20 by the ignition switch 31, power is supplied to the microcomputer 10. That is, when the ignition switch 31 is turned on, power is supplied to the microcomputer 10, and the microcomputer 10 operates. On the other hand, when power is cut off between the battery 30 and the power supply circuit 20 by the ignition switch 31, power is not supplied to the microcomputer 10. That is, when the ignition switch 31 is turned off, power is not supplied to the microcomputer 10, and the microcomputer 10 stops operating.

[0024] When the ignition switch 31 is turned on, the microcomputer 10 controls the power supplied to the motor 40. The microcomputer 10 is composed of, for example, a microprocessing unit. The power supply circuit 20 is connected to the microcomputer 10. The power supply circuit 20 is a packaged logic circuit obtained by combining an electronic circuit and a trigger. The power supply circuit 20 is a so-called ASIC (application specific integrated circuit). The microcomputer 10 reads a program stored in its storage unit 11 and executes an operation corresponding to the program.

[0025] The torque sensor 50 is connected to the power supply circuit 20. The torque sensor 50 is, for example, a sensor that detects the steering operation torque Th applied to the steering shaft of the steering device. When power is supplied between the battery 30 and the power supply circuit 20 by the ignition switch 31, power is supplied to the torque sensor 50. That is, when the ignition switch 31 is turned on, power is supplied to the torque sensor 50, and the torque sensor 50 operates. On the other hand, when power is cut off between the battery 30 and the power supply circuit 20 by the ignition switch 31, power is not supplied to the torque sensor 50. That is, when the ignition switch 31 is turned off, power is not supplied to the torque sensor 50, and the torque sensor 50 stops operating. In addition, the torque sensor 50 is connected to the microcomputer 10. The torque sensor 50 outputs an output signal based on the detected steering operation torque Th to the microcomputer 10. In addition, there are various types of torque sensors 50, each of which has a different operating voltage Vt required for the torque sensor 50 to operate. For example, the torque sensor 50 may be a torque sensor that outputs the detected steering torque Th as a voltage (i.e., an analog value) or a torque sensor that outputs the detected steering torque Th as a digital value. Therefore, in the present embodiment, the motor control device 1 is configured to be able to apply different operating voltages Vt to the torque sensor 50 in accordance with the type of the torque sensor 50.

[0026] The storage unit 11 of the microcomputer 10 stores identification information I corresponding to the type of the torque sensor 50 connected to the motor control device 1 of the present embodiment. The identification information I of the present embodiment is information indicating the output mode of the output signal of the torque sensor 50, that is, whether it is an analog signal or a digital signal. The microcomputer 10 outputs the identification information I to the power supply circuit 20 at the timing when the ignition switch 31 is turned on. The microcomputer 10 grasps the output mode of the output signal of the torque sensor 50 based on the communication standard of the connector of the torque sensor 50 connected to the connector of the microcomputer 10. When the output mode of the output signal of the torque sensor 50 is to output in analog value, the microcomputer 10 outputs, for example, 0 as the identification information I for generating the operating voltage Vt corresponding to the torque sensor 50 outputting the analog value. In addition, when the output mode of the output signal of the torque sensor 50 is to output in digital value, the microcomputer 10 outputs, for example, 1 as the identification information I for generating the operating voltage Vt corresponding to the torque sensor 50 outputting the digital value. An example of the first sensor described in the claims is a torque sensor 50 that outputs an analog value, and an example of the second sensor described in the claims is a torque sensor 50 that outputs a digital value.

[0027] The power supply circuit 20 includes a voltage applying unit 60 and a switching unit 70, and is connected to a reference voltage generating unit 80 and a power supply voltage generating unit 90. The reference voltage generating unit 80 generates a reference voltage Vref of a constant voltage based on a battery voltage V of the battery 30. An example of the second reference voltage generating circuit described in the claims is the reference voltage generating unit 80, and an example of the second reference voltage described in the claims is the reference voltage Vref.

[0028] The power supply voltage generating unit 90 generates a power supply voltage Vcc of a constant voltage based on the reference voltage Vref generated by the reference voltage generating unit 80. The microcomputer 10 operates based on the power supply voltage Vcc generated by the power supply voltage generating unit 90. An example of the first reference voltage generating circuit described in the claims is the power supply voltage generating unit 90, and an example of the first reference voltage described in the claims is the power supply voltage Vcc.

[0029] The switching unit 70 is a multiplexer that outputs two or more inputs as one signal. Specifically, the switching unit 70 obtains the reference voltage Vref generated by the reference voltage generating unit 80 and the power supply voltage Vcc generated by the power supply voltage generating unit 90. In addition, the switching unit 70 obtains the identification information I output from the microcomputer 10. The switching unit 70 outputs either the reference voltage Vref or the power supply voltage Vcc as a reference voltage based on the obtained identification information I. Specifically, the switching unit 70 outputs the power supply voltage Vcc when the identification information I is 0, and outputs the reference voltage Vref when the identification information I is 1. Thus, the switching unit 70 outputs either the reference voltage Vref or the power supply voltage Vcc selected corresponding to the type of the torque sensor 50.

[0030] The voltage applying unit 60 applies the operating voltage Vt to the torque sensor 50 using the battery voltage V supplied from the battery 30 via the ignition switch 31. The voltage applying unit 60 generates the operating voltage Vt of the torque sensor 50 by stepping down the battery voltage V supplied from the battery 30 based on either the reference voltage Vref or the power supply voltage Vcc selected by the switching unit 70. The voltage applying unit 60 includes an operational amplifier 61 and a transistor 62.

[0031] The transistor 62 is provided on the power supply line L between the ignition switch 31 and the torque sensor 50. The transistor 62 adopts a MOS-FET (field effect transistor: metal-oxide-semiconductor field-effect-transistor). The source of the transistor 62 is connected to the ignition switch 31 side of the positive electrode side of the battery 30, and the drain of the transistor 62 is connected to the torque sensor 50 side. In addition, the gate of the transistor 62 is connected to the output terminal of the operational amplifier 61. The inverting input terminal of the operational amplifier 61 is connected to the output terminal of the switching unit 70. The non-inverting input terminal of the operational amplifier 61 is connected to the node N1 of the part provided on the power supply line L between the transistor 62 and the torque sensor 50. By configuring the operational amplifier 61 in this way, negative feedback of the operational amplifier 61 is performed. The operational amplifier 61 outputs a gate voltage Vg, which is a voltage based on the deviation between the voltage input to the inverting input terminal and the feedback voltage Vr input to the non-inverting input terminal, from the output terminal. According to the setting of the operational amplifier 61, the gate voltage Vg may be larger, smaller, or equal to the deviation between the voltage input to the inverting input terminal and the feedback voltage Vr input to the non-inverting input terminal. By switching the transistor 62 on and off in accordance with the gate voltage Vg applied to the gate of the transistor 62, the operating voltage Vt of the torque sensor 50 is generated according to the battery voltage V of the battery 30. Specifically, the transistor 62 generates the operating voltage Vt of the torque sensor 50 that outputs an analog value by stepping down the battery voltage V of the battery 30 when the gate voltage Vg based on the deviation between the power supply voltage Vcc and the feedback voltage Vr is applied to the gate. In addition, the transistor 62 can also generate the operating voltage Vt of the torque sensor 50 that outputs a digital value by stepping down the battery voltage V of the battery 30 when the gate voltage Vg based on the deviation between the reference voltage Vref and the feedback voltage Vr is applied to the gate. Thus, the voltage applying unit 60 can apply the operating voltage Vt corresponding to the type of the torque sensor 50 to the torque sensor 50 based on the power supply voltage Vcc or the reference voltage Vref as the reference voltage of the voltage applying unit 60 applied by the switching unit 70 .

[0032] use Figure 2 The reference voltage generating section 80 and the power supply voltage generating section 90 will be described. Figure 2 The reference voltage generating unit 80 and the power supply voltage generating unit 90 are schematically shown. Figure 2 In order to simplify the description, illustration of resistors and the like is omitted.

[0033] like Figure 2As shown, the power supply voltage generating unit 90 generates the power supply voltage Vcc using the reference voltage Vref generated by the reference voltage generating unit 80. The reference voltage generating unit 80 generates the reference voltage Vref of a constant voltage according to the battery voltage V by using a pre-regulator or by using a resistor divider or the like. The power supply voltage generating unit 90 includes an operational amplifier 91. The inverting input terminal of the operational amplifier 91 is connected to the output terminal of the reference voltage generating unit 80. The output terminal of the operational amplifier 91 is connected to the non-inverting input terminal of the operational amplifier 91 so that the output from the output terminal of the operational amplifier 91 becomes the input of the non-inverting input terminal of the operational amplifier 91. By configuring the operational amplifier 91 in this way, negative feedback of the operational amplifier 91 is performed. Furthermore, the operational amplifier 91 outputs a voltage based on the deviation between the reference voltage Vref and the voltage input from the non-inverting input terminal of the operational amplifier 91 from the output terminal. By stabilizing the voltage output from the output terminal of the operational amplifier 91, the power supply voltage Vcc of a constant voltage is obtained. Thus, the power supply voltage generating unit 90 generates the power supply voltage Vcc using the reference voltage Vref.

[0034] The operation and effects of the first embodiment will be described.

[0035] (1) The reference voltage applied to the voltage applying unit 60 can be switched by the switching unit 70 in accordance with the type of the torque sensor 50. That is, the switching unit 70 selects the reference voltage Vref or the power supply voltage Vcc to output, thereby switching the voltage applied to the inverting input terminal of the operational amplifier 61 of the voltage applying unit 60 and switching the gate voltage Vg applied to the transistor 62 of the voltage applying unit 60. As a result, the transistor 62 can step down the battery voltage V of the battery 30 to the appropriate operating voltage Vt corresponding to the type of the torque sensor 50 based on the gate voltage Vg corresponding to the type of the torque sensor 50. Therefore, the appropriate operating voltage Vt corresponding to the type of the torque sensor 50 can be applied to the torque sensor 50 by the voltage applying unit 60. Since the operating voltage Vt can be applied in a manner corresponding to the type of the torque sensor 50, the types of the power supply circuit 20 prepared in advance can be reduced, and the complexity of the management of the power supply circuit 20 can be suppressed.

[0036] (2) The power supply circuit 20 of this embodiment can be used for a plurality of types of torque sensors 50, thereby improving the versatility of the power supply circuit 20. This can reduce the types of power supply circuits 20 that need to be prepared separately in advance according to the types of torque sensors 50.

[0037] (3) As a comparative example, in order to improve the versatility of the power supply circuit 20, for example, it is considered to make the circuit structure of the power supply circuit 20 directly redundant. In this case, the power supply circuit 20 is redundantly provided with: a first voltage applying unit that directly inputs the reference voltage Vref generated by the reference voltage generating unit 80 to the inverting input terminal of the operational amplifier 61, and a second voltage applying unit that directly inputs the power supply voltage Vcc generated by the power supply voltage generating unit 90 to the inverting input terminal of the operational amplifier 61. The power supply circuit 20 is also provided with a selection structure that selects which of the two voltage applying units is used. As a result, the power supply circuit 20 becomes larger. Therefore, it is necessary to achieve a compromise between being able to use the power supply circuit 20 for multiple types of torque sensors 50 and miniaturization of the power supply circuit 20. In this regard, in the present embodiment, the reference voltage of the voltage applying unit 60 is switched by the switching unit 70, so that the operating voltage Vt of the torque sensor 50 is variable. The voltage applying unit 60 is a structure that the conventional power supply circuit 20 has, and only the switching unit 70 is added as a new structure in the power supply circuit 20. Therefore, the power supply circuit 20 can be used for a plurality of types of torque sensors 50, and the power supply circuit 20 can be made smaller than in the case of the above-mentioned comparative example.

[0038] (4) The torque sensor 50 has different operating voltages Vt required for operation. For example, the torque sensor 50 may output the steering torque Th as an analog value or a digital value, and the operating voltages Vt of these torque sensors may be different. Therefore, the switching unit 70 is configured to select an appropriate reference voltage as the reference voltage of the voltage applying unit 60 according to the output mode of the torque sensor 50. Thus, the voltage applying unit 60 can apply the operating voltage Vt corresponding to the reference voltage Vref or the power supply voltage Vcc, that is, the operating voltage Vt corresponding to the output mode of the torque sensor 50, to the torque sensor 50. For example, when the operating voltage Vt is applied to the torque sensor 50 that outputs as an analog value, the switching unit 70 can select the power supply voltage Vcc as the reference voltage of the voltage applying unit 60. In addition, for example, when the operating voltage Vt is applied to the torque sensor 50 that outputs as a digital value, the switching unit 70 can select the reference voltage Vref as the reference voltage of the voltage applying unit 60.

[0039] (5) The motor control device 1 outputs the identification information I corresponding to the type of the torque sensor 50 connected to the power circuit 20 to the switching unit 70 at the timing when the ignition switch 31 is turned on. Thus, the switching unit 70 can switch the reference voltage of the voltage applying unit 60 to the reference voltage corresponding to the type of the torque sensor 50 based on the identification information I, so that the operating voltage Vt of the torque sensor 50 can be made variable corresponding to the type of the torque sensor 50. The operating voltage Vt can be applied in a manner corresponding to the type of the torque sensor 50, so the types of the power circuit 20 prepared in advance can be reduced, thereby suppressing the complexity of the management of the power circuit 20. In addition, the type of the torque sensor 50 can be distinguished using the identification information I obtained by connecting the torque sensor 50 to the power circuit 20, so that an appropriate operating voltage Vt can be applied to the torque sensor 50.

[0040] (6) When the operating voltage Vt is applied to the torque sensor 50 that outputs an analog value, after the power supply voltage Vcc is selected as the reference voltage output from the switching unit 70 to the voltage applying unit 60, the following effects can be obtained. When the switching unit 70 outputs a voltage other than the power supply voltage Vcc to the voltage applying unit 60, the power supply voltage Vcc and the reference voltage of the voltage applying unit 60 sometimes do not change in the same way but change independently. In the case of the torque sensor 50 that outputs the steering torque Th as an analog value, the microcomputer 10 reads the analog value (voltage) from the torque sensor 50 based on its own operating voltage, that is, the power supply voltage Vcc. Therefore, when the power supply voltage Vcc and the operating voltage Vt of the torque sensor 50 change independently, the reference for reading the analog value from the torque sensor 50 by the microcomputer 10 changes, and thus the reading error of the analog value from the torque sensor 50 becomes larger. In this regard, in the present embodiment, the reference voltage of the voltage applying unit 60 and the power supply voltage Vcc, which is the operating voltage of the microcomputer 10, are made to have the same potential, so that the relative error between the voltage detected by the torque sensor 50 and the power supply voltage Vcc, which is the reference for reading from the torque sensor 50, can be reduced. In this way, in the case of the torque sensor 50 that outputs an analog value, the microcomputer 10 selects the power supply voltage Vcc as the reference voltage of the voltage applying unit 60, so that the voltage output from the torque sensor 50 can be read more appropriately compared to the case where a voltage other than the power supply voltage Vcc is selected as the reference voltage.

[0041] A motor control device according to a second embodiment will be described. Here, the description will focus on the differences from the first embodiment.

[0042] Figure 3The power supply circuit 20 of the motor control device 1 is shown. The power supply circuit 20 has a terminal portion 21. Based on the operation of the switch provided in the power supply circuit 20 by the operator, the terminal portion 21 is switched to a predetermined identification state S. The operator switches the identification state S of the switch in accordance with the type of the torque sensor 50. When an operating voltage Vt corresponding to the torque sensor 50 outputting an analog value is generated, as the identification state S, for example, the terminal portion 21 is switched to an analog switching position, and when an operating voltage Vt corresponding to the torque sensor 50 outputting a digital value is generated, as the identification state S, for example, the terminal portion 21 is switched to a digital switching position.

[0043] The switching unit 70 outputs one of the reference voltage Vref and the power supply voltage Vcc as a reference voltage based on the identification state S. Specifically, the switching unit 70 outputs the power supply voltage Vcc when the identification state S is an analog switching position, and outputs the reference voltage Vref when the identification state S is a digital switching position. Thus, the switching unit 70 outputs one of the reference voltage Vref and the power supply voltage Vcc selected in accordance with the type of the torque sensor 50.

[0044] The operation and effects of the second embodiment will be described.

[0045] (7) The switching unit 70 can switch the reference voltage of the voltage applying unit 60 based on the identification state S corresponding to the type of the torque sensor 50. Since the terminal unit 21 for outputting the identification state S is provided in the power supply circuit 20, the microcomputer 10 does not need to be provided with a structure for outputting the identification state S, and accordingly, the microcomputer 10 can be simply configured.

[0046] In addition, each embodiment may be modified as follows. In addition, the following other embodiments can be combined with each other within the scope of no technical contradiction.

[0047] In each embodiment, the power supply voltage generating unit 90 generates the power supply voltage Vcc using the reference voltage Vref generated by the reference voltage generating unit 80, but the present invention is not limited thereto. For example, the power supply voltage generating unit 90 may generate a constant power supply voltage Vcc according to the battery voltage V by using a pre-regulator or by using a resistor divider. In this case, the reference voltage generating unit 80 may also generate the reference voltage Vref using the power supply voltage Vcc generated by the power supply voltage generating unit 90.

[0048] The voltage applying unit 60 is composed of an operational amplifier 61 and a transistor 62, but is not limited thereto. For example, the voltage applying unit 60 may also be composed of resistor division or the like. In each embodiment, the identification information I and the identification state S are information indicating 0 or 1, but are not limited thereto. For example, the identification information I and the identification state S may also be a character string indicating the specification of the torque sensor 50. In this case, the switching unit 70 reads the character string of the identification information I and the identification state S to switch the reference voltage.

[0049] In the first embodiment, the microcomputer 10 outputs the identification information I to the switching unit 70 when the ignition switch 31 is turned on, but the present invention is not limited thereto. For example, the microcomputer 10 may intermittently output the identification information I to the switching unit 70 while the ignition switch 31 is turned on.

[0050] The power supply circuit 20 may also include a reference voltage generating unit 80 and a power supply voltage generating unit 90. In each embodiment, the switching unit 70 selects and outputs any one of the two voltages, the reference voltage Vref and the power supply voltage Vcc, based on the identification information I and the identification state S as the reference voltage, but the present invention is not limited thereto. For example, the switching unit 70 may also obtain three or more voltages, and select and output any one of the three or more voltages obtained based on the identification information I and the identification state S as the reference voltage.

[0051] In each embodiment, the switching unit 70 switches the reference voltage of the voltage applying unit 60 based on the identification information I and the identification state S corresponding to the type of output method of the output signal of the torque sensor 50, but the present invention is not limited to this.

[0052] For the torque sensor 50, sometimes, even if the output mode of the output signal based on the detected steering torque Th is the same, the action voltage Vt required for the action is different. For example, in the torque sensors 50 of different styles and the torque sensors 50 of different measurement objects for measuring the steering torque Th, even if the output mode is the same, the action voltage Vt required for the action is different. Even in such a case, a plurality of reference voltages corresponding to the differences in the style and measurement object of the torque sensor 50 can be input to the switching unit 70 in advance, and the switching unit 70 switches the reference voltage of the voltage applying unit 60 based on the identification information I and the identification state S.

[0053] The torque sensor 50 includes magnetostrictive type, piezoelectric type, and other torque sensors that detect the steering torque Th in different ways. In such torque sensors 50, the required operating voltage Vt for operation may be different. Even in such a case, a plurality of reference voltages corresponding to the method of detecting the steering torque Th may be input to the switching unit 70 in advance, and the switching unit 70 may switch the reference voltage of the voltage applying unit 60 based on the identification information I and the identification state S.

[0054] In each embodiment, the voltage applying unit 60 of the power supply circuit 20 applies the operating voltage Vt to the torque sensor 50, but the present invention is not limited thereto. For example, the power supply circuit 20 may apply the operating voltage Vt to the rotation angle sensor or the vehicle speed sensor. In this case, the motor control device 1 may control the motor based on the rotation angle sensor.

[0055] In each embodiment, the vehicle equipped with the motor control device of the present embodiment may be a vehicle having an internal combustion engine in which an engine is used as a vehicle driving source, or may be a so-called electric vehicle in which a motor is used as a vehicle driving source. In addition, in the case of an electric vehicle, the start switch is a switch for starting the motor as the vehicle driving source.

Claims

1. A power supply circuit connected to a control device, the power supply circuit comprising: a voltage applying unit that applies an operating voltage based on a reference voltage to a sensor that outputs an output value based on a detected state quantity; a switching unit configured to switch the reference voltage of the voltage applying unit so as to become a voltage required for operating the sensor in accordance with the type of the sensor; as well as a first reference voltage generating circuit for generating a first reference voltage, One of the sensors is a first sensor that outputs a voltage based on a detected state quantity to the control device. The switching unit is configured to select, when the voltage applying unit applies an operating voltage to the first sensor, the first reference voltage generated by the first reference voltage generating circuit and having the same potential as the power supply voltage of the control device generated based on the voltage of the battery as a reference voltage for the voltage applying unit.

2. The power supply circuit according to claim 1, wherein: The power supply circuit further includes a second reference voltage generating circuit for generating a second reference voltage. One of the sensors is a second sensor that outputs a detected state quantity in a digital value. The switching unit is configured to select the second reference voltage generated by the second reference voltage generating circuit based on the battery voltage as the reference voltage of the voltage applying unit when the voltage applying unit applies the operating voltage to the second sensor.

3. A motor control device comprising the power supply circuit according to claim 1 or 2 and a control device connected to the power supply circuit, wherein: When the vehicle's start switch is turned on, the control device is powered from the battery. The control device stores identification information corresponding to the type of the sensor and controls the driving of the motor. When the start switch is turned on, the control device outputs the identification information corresponding to the type of the sensor connected to the power circuit to the switching unit, The switching unit switches the reference voltage of the voltage applying unit based on the identification information.

4. A motor control device comprising the power supply circuit according to claim 1 or 2 and a control device connected to the power supply circuit, wherein: When the vehicle's start switch is turned on, the control device is powered from the battery. The control device stores identification information corresponding to the type of the sensor and controls the driving of the motor. The power supply circuit includes a terminal portion that outputs an identification state for identifying the type of the sensor to the switching portion. The switching unit switches the reference voltage of the voltage applying unit based on the recognition state.

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