Rotation detector

Abstract

To provide a rotation detector capable of executing more stable rotation position detection processing.SOLUTION: The rotation detector 1 includes a magnet 10 rotating together with a rotation shaft 11, a power generation circuit 20 having a power generation element 21 generating power by utilizing the large Barkhausen effect, a magnetic sensor 41, an information processing part 42 detecting the rotation position of the rotation shaft 11, and a power supply part 30 supplying power to the magnetic sensor 41 and the information processing part 42, the power generation circuit 20 includes a first power storage part 23 storing power generated by the power generation element 21, a second power storage part 26 for storing power, and a power storage control part 27 controlling charging and discharging according to the voltage of the first power storage part 23 and the voltage of the second power storage part 26, the first power storage device 23 supplies power necessary for the rotation position detection processing to the power supply unit 30. At the end of the rotation position detection processing, the second power storage device 26 stores part of the power remaining in the first power storage device 23 before the first power storage device 23 is discharged to the outside in the discharge processing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a rotation detector. [Background technology]

[0002] Conventionally, there is known a rotation detector that detects the rotation of a rotating shaft of a motor. Also known as a rotation detector is a rotation detector that detects rotation by power supplied from a power generating circuit that generates power by changes in the magnetic field caused by a magnet attached to the rotating shaft when there is no power supply from a battery or an external power source (for example, Patent Document 1).

[0003] Also known is a rotation detector disclosed in Patent Document 1, in which the power supply source is selected from the power generation circuit, a primary battery, a secondary battery, or an external power supply (for example, Patent Document 2). When a secondary battery is selected as a component of the power supply source, the secondary battery operates in a configuration that allows it to be charged only from the power generation circuit or an external power supply, so the power supply source requires either a primary battery or an external power supply as an essential component in addition to the power generation circuit and secondary battery. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6610697 [Patent Document 2] Patent No. 6772698 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in a rotation detector that does not have a primary or secondary battery, such as the rotation detector disclosed in Patent Document 2, there is a problem in that it is not possible to execute the rotation position detection process in cases where it is not possible to supply power from an external power source and the power supplied from the power generation circuit does not reach the power required for rotation detection.

[0006] The present disclosure has been made to solve such problems, and has an object to provide a rotation detector that can execute a more stable rotation position detection process. [Means for solving the problem]

[0007] A rotation detector according to one aspect of the present disclosure includes a magnet that rotates together with a rotation shaft, a power generation circuit having a power generation element that generates power by utilizing the Great Barkhausen effect caused by a change in a magnetic field due to the rotation of the magnet together with the rotation shaft, a magnetic sensor that detects the change in the magnetic field, an information processing unit that detects a rotation position of the rotation shaft using the power generation element and the magnetic sensor, and a power supply unit that supplies power generated by the power generation element to the magnetic sensor and the information processing unit, and the power generation circuit includes a first power storage unit that stores the power generated by the power generation element, and a first voltage detector that detects a voltage generated by the power generation element. The information processing unit includes a detection unit, a second storage unit for storing power, a second voltage detection unit for detecting the voltage of the second storage unit, and a storage control unit for controlling the first storage unit and the second storage unit, wherein the first storage unit supplies the power supply unit with a predetermined amount of power required for the rotational position detection process executed by the information processing unit, the storage control unit controls charging and discharging of the first storage unit and the second storage unit according to the voltages detected by the first voltage detection unit and the second voltage detection unit, and the second storage unit stores a portion of the power remaining in the first storage unit before the first storage unit discharges the power to the outside in a discharging process at the end of the rotational position detection process. [Effects of the Invention]

[0008] According to the present disclosure, a rotation detector capable of executing a more stable rotation position detection process is provided. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing the configuration of a rotation detector according to an embodiment. [Figure 2]FIG. 2 is a diagram for explaining the relationship between the voltage generated by the power generating element and the voltage threshold value according to the embodiment. [Figure 3] FIG. 3 is a diagram showing a first circuit configuration of the rotation detector according to the embodiment. [Figure 4] FIG. 4 is a diagram showing a second circuit configuration of the rotation detector according to the embodiment. [Figure 5] FIG. 5 is a diagram showing a third circuit configuration of a rotation detector according to an embodiment. [Figure 6] FIG. 6 is a diagram showing a fourth circuit configuration of a rotation detector according to an embodiment. [Figure 7] FIG. 7 is a flowchart showing the operation of the rotation detector according to the embodiment. [Figure 8] FIG. 8 is a timing chart showing a specific example of the operation of the rotation detector according to the embodiment. [Figure 9] FIG. 9 is a timing chart showing another specific example of the operation of the rotation detector according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each of the embodiments described below represents a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, component placement positions, connection forms, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, components that are not recited in the independent claims of the present disclosure will be described as optional components.

[0011] Note that each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, the scales and the like do not necessarily match in each figure. Furthermore, in each figure, the same reference numerals are used for substantially the same configurations, and redundant explanations will be omitted or simplified.

[0012] Furthermore, in this specification, terms indicating the relationship between elements, such as orthogonal and parallel, terms indicating the shape of elements, such as rectangle, and numerical ranges are not expressions that only express a strict meaning, but are expressions that also include a substantially equivalent range, for example, a difference of about a few percent.

[0013] Furthermore, the terms "up" and "down" in the following description of the rotation detector according to the present disclosure do not refer to the upward direction (vertically upward) and downward direction (vertically downward) in absolute spatial recognition, but are directions determined by relative positional relationships, and do not limit the orientation of the rotation detector according to the present disclosure during manufacture or use.

[0014] (Embodiment) The rotation detector according to this embodiment will be described below.

[0015] [composition] First, the configuration of the rotation detector according to the present embodiment will be described. Fig. 1 is a block diagram showing the configuration of a rotation detector 1 according to the embodiment.

[0016] 1, the rotation detector 1 includes a magnet 10, a power generation circuit 20, a power supply unit 30, a magnetic sensor 41, and an information processing unit 42. The rotation detector 1 is used in combination with a motor such as a servo motor, and is a device that detects the rotational position of the rotating shaft of the motor.

[0017] The magnet 10 applies a magnetic field to the power generating element 21 and the magnetic sensor 41 included in the power generating circuit 20. The magnet 10 is, for example, a plate-shaped magnet. The magnet 10 may also be a magnet of another shape, such as a rod-shaped magnet, as long as it can change the magnetic field applied to the power generating element 21 and the magnetic sensor 41. There may also be a plurality of magnets 10.

[0018] Magnet 10 is fixed to rotating shaft 11 via a rotating plate, and rotates together with the rotating plate around the rotation axis of rotating shaft 11. The rotating plate is made of, for example, metal, resin, glass, or ceramic. Magnet 10 may also be fixed to rotating shaft 11 by a member other than the rotating plate.

[0019] The power generation circuit 20 is an electric circuit having a power generation element 21, a first voltage detection unit 22, a first power storage unit 23, a switch 24, a second voltage detection unit 25, a second power storage unit 26, and a power storage control unit 27.

[0020] The power generating element 21 generates power by changing the magnetic field formed by the magnet 10 as the magnet 10 rotates, specifically by reversing the direction of the magnetic field, and outputs the generated power. The power generating element 21 generates power by utilizing the large Barkhausen effect, which occurs due to the change in the magnetic field caused by the rotation of the magnet 10 together with the rotation shaft 11.

[0021] The power generating element 21 includes, for example, a magnetic member and a coil wound around the magnetic member.

[0022] The magnetic member is a magnetic material that generates the large Barkhausen effect. A specific example of the magnetic member is a Wiegand wire. The Wiegand wire is a magnetic material whose magnetization direction aligns to one side of the longitudinal direction when a magnetic field of a predetermined magnitude or greater is applied along the longitudinal direction of the Wiegand wire. Specifically, the Wiegand wire includes a soft magnetic portion and a hard magnetic portion extending along the longitudinal direction. When the direction of the magnetic flux flowing along the longitudinal direction of the Wiegand wire changes, the magnetization direction of the soft magnetic portion of the Wiegand wire suddenly reverses, inducing a pulse-like voltage (voltage pulse) across both ends of the coil wound around the Wiegand wire. In this way, the power generating element 21 generates power (generates a power generation pulse), outputting a voltage higher than that of conventional induction power generation. The magnetic member is not particularly limited as long as it generates the large Barkhausen effect, and may be a magnetic material other than Wiegand wire.

[0023] The first voltage detection unit 22 detects the voltage VWC generated by the power generation element 21. The first voltage detection unit 22 has a voltage threshold for detecting the voltage VWC generated by the power generation element 21. The voltage threshold will be described in detail later, but the first voltage detection unit 22 has at least a first voltage threshold and a second voltage threshold that is greater than the first voltage threshold. The first voltage detection unit 22 is configured, for example, with a comparator corresponding to each voltage threshold. That is, in this example, having a voltage threshold means having a comparator that compares the voltage VWC with the voltage threshold. The first voltage detection unit 22 outputs the voltage detection result to the power storage control unit 27. For example, when the voltage VWC input to the comparator exceeds the voltage threshold, the first voltage detection unit 22 outputs a signal indicating that the voltage threshold has been exceeded to the power storage control unit 27.

[0024] First power storage unit 23 stores the power (in other words, the charge) generated by power generating element 21. First power storage unit 23 is configured, for example, by a capacitor or the like.

[0025] First power storage unit 23 uses the stored power to supply power supply unit 30 with the power required for the rotational position detection process executed by information processing unit 42. The rotational position detection process will be described in detail later.

[0026] After the above rotational position detection process is completed, first power storage unit 23 discharges the remaining power in first power storage unit 23 to the outside (for example, to ground).

[0027] Switch 24 is a switch such as a mechanical relay that switches the electrical connection relationship between first power storage unit 23 and second power storage unit 26.

[0028] Second voltage detection unit 25 detects the voltage of second power storage unit 26. Second voltage detection unit 25 has a voltage threshold for detecting the voltage of second power storage unit 26. Details of the voltage threshold will be described later, but second voltage detection unit 25 has a third voltage threshold that is at least greater than the first voltage threshold and less than the second voltage threshold. Second voltage detection unit 25 is configured, for example, with a comparator corresponding to the voltage threshold. That is, in this example, having a voltage threshold means having a comparator that compares the voltage detected by second voltage detection unit 25 with the voltage threshold. Second voltage detection unit 25 outputs the voltage detection result to power storage control unit 27. For example, when the voltage input to the comparator exceeds the voltage threshold, second voltage detection unit 25 outputs a signal indicating that the voltage threshold has been exceeded to power storage control unit 27.

[0029] Second power storage unit 26 stores a portion of the power (in other words, charge) remaining in first power storage unit 23 at the end of the rotational position detection process before first power storage unit 23 discharges to the outside in the discharge process. Second power storage unit 26 may be formed of a fixed capacitor or a variable capacitor, or may be formed of a plurality of fixed capacitors or a plurality of variable capacitors. Second power storage unit 26 may also be formed of a battery. The battery is, for example, a secondary battery such as a lithium ion battery.

[0030] The power storage control unit 27 is a processing circuit that controls the operation of the power generation circuit 20. The power storage control unit 27 controls the charging and discharging of the first power storage unit 23 and the second power storage unit 26 in accordance with the voltages detected by the first voltage detection unit 22 and the second voltage detection unit 25. Details of the charging and discharging of the first power storage unit 23 and the second power storage unit 26 controlled by the power storage control unit 27 will be described later, but the power storage control unit 27 controls the charging and discharging of the first power storage unit 23 and the second power storage unit 26 based on at least the voltages detected by the first voltage detection unit 22 and the second voltage detection unit 25, a first voltage threshold, a second voltage threshold, and a third voltage threshold.

[0031] When the power stored in the first power storage unit 23 is less than the predetermined power required to execute the rotational position detection process (i.e., less than the second voltage threshold), the power storage control unit 27 executes a complementary process to discharge the power stored in the second power storage unit 26 to the first power storage unit 23, thereby increasing the power supplied by the first power storage unit 23 to the power supply unit 30.

[0032] The power storage control unit 27 is realized by, for example, a processor etc. That is, the functions of the power storage control unit 27 are realized by the processor etc. executing a program stored in a memory.

[0033] Note that one voltage detector may be used to realize the functions of first voltage detection unit 22 and second voltage detection unit 25. Specifically, one voltage detector may detect the voltage generated by power generation element 21, the voltage of first power storage unit 23, and the voltage of second power storage unit 26 while switching the target to be detected.

[0034] The power supply unit 30 supplies the power generated by the power generating element 21 (power supplied by the first power storage unit 23) to the magnetic sensor 41 and the information processing unit 42. The power supply unit 30 is, for example, an LDO (Low Drop Out) regulator. The power supply unit 30 outputs a constant voltage VLDO using, for example, ground potential as a reference potential and the voltage across the capacitor of the first power storage unit 23 as an input voltage. The voltage VLDO output from the power supply unit 30 is supplied to the power generation circuit 20, the magnetic sensor 41, and the information processing unit 42.

[0035] The magnetic sensor 41 detects the magnetic field generated by the magnet 10, and is, for example, a magnetoresistive element (Tunnel Magneto Resistive (TMR) element) sensor or a Hall element sensor. The magnetic sensor 41 is provided corresponding to the power generating element 21.

[0036] The information processing unit 42 is a processing circuit that detects the rotational position of the rotating shaft 11 using the power generating element 21 and the magnetic sensor 41 (i.e., executes rotational position detection processing). The information processing unit 42 is realized, for example, by a processor or the like. That is, the function of the information processing unit 42 is realized by the processor or the like executing a program stored in memory. The information processing unit 42, for example, determines the polarity of the voltage generated in the power generating element 21 and the polarity of the magnet 10 that applies a magnetic field to the magnetic sensor 41, and stores the determination result in memory as rotational position information.

[0037] The information processing unit 42 outputs a multiple rotation processing signal MSC, which is a control signal to the power storage control unit 27 and the magnetic sensor 41, based on information input from the power generating element 21 and the magnetic sensor 41.

[0038] The charge / discharge control performed by power storage control unit 27 does not necessarily have to be achieved by switch 24. For example, power storage control unit 27 may control the charge / discharge by controlling the current flowing between first power storage unit 23 and second power storage unit 26 by increasing or decreasing the voltage of the power stored in second power storage unit 26 using a converter or the like.

[0039] [Voltage Threshold] Next, the voltage thresholds of the first voltage detection unit 22 and the second voltage detection unit 25 will be described with reference to Fig. 2. Fig. 2 is a diagram for explaining the relationship between the voltage generated by the power generation element 21 according to the embodiment and the voltage thresholds of the first voltage detection unit 22 and the second voltage detection unit 25. In Fig. 2, the vertical axis represents the voltage generated by the power generation element 21 generating power. In Fig. 2, the waveform Pr represents regular power generation, and the waveforms Pi1 and Pi2 represent irregular power generation.

[0040] The voltage VWC_DET is a first voltage threshold of the first voltage detection unit 22. The voltage VWC_DET is a first-stage determination voltage in a two-stage voltage detection configuration. The voltage VWC_DET is set higher than the voltage reached by induction power generation and is a voltage threshold used to determine whether the voltage VWC is a voltage generated by the large Barkhausen effect or a voltage generated by induction power generation. For example, when the voltage VWC is equal to or higher than the voltage VWC_DET, as in the waveform Pr or waveform Pi1, the power storage control unit 27 determines that the voltage is generated by the large Barkhausen effect. Furthermore, when the voltage VWC is lower than the voltage VWC_DET, as in the waveform Pi2, the power storage control unit 27 determines that the voltage is generated by induction power generation. Alternatively, the power storage control unit 27 determines that the voltage generated by the large Barkhausen effect is abnormally lower than a second voltage threshold, which will be described later.

[0041] The voltage VWC_OK is a second voltage threshold of the first voltage detection unit 22. The voltage VWC_OK is a second-stage determination voltage in the two-stage voltage detection configuration. The voltage VWC_OK is a voltage threshold used to determine whether the first power storage unit 23 can supply the power supply unit 30 with the power required for the rotational position detection process described above. For example, when the voltage VWC is equal to or greater than the voltage VWC_OK as shown in the waveform Pr, the power storage control unit 27 determines that the first power storage unit 23 can supply the required power to the power supply unit 30 and controls the first power storage unit 23 to supply the required power to the power supply unit 30. Furthermore, when the voltage VWC is smaller than the voltage VWC_OK as shown in the waveform Pi1 or Pi2, the power storage control unit 27 determines that the first power storage unit 23 cannot supply the required power to the power supply unit 30 and controls the first power storage unit 23 not to supply the required power to the power supply unit 30.

[0042] Voltage VWC_CHGON is a fourth voltage threshold of first voltage detection unit 22. Voltage VWC_CHGON is a voltage threshold used to determine whether or not to discharge a portion of the power remaining in first power storage unit 23 to second power storage unit 26 before first power storage unit 23 discharges to ground in a discharging process at the end of the rotational position detection process. For example, when the voltage of first power storage unit 23 at the end of the rotational position detection process is equal to or higher than voltage VWC_CHGON, power storage control unit 27 performs control to store power from first power storage unit 23 to second power storage unit 26. Furthermore, when the voltage of first power storage unit 23 at the end of the rotational position detection process is lower than voltage VWC_CHGON, power storage control unit 27 performs control not to store power from first power storage unit 23 to second power storage unit 26.

[0043] The voltage VWC_CHGON may be a voltage threshold determined by the power storage control unit 27 each time the power generating element 21 generates power, or may be a fixed voltage threshold. For example, the power storage control unit 27 determines the voltage VWC_CHGON based on the amount of power generated by the power generating element 21, the power stored in the first power storage unit 23 and the second power storage unit 26, and the capacitances of the first power storage unit 23 and the second power storage unit 26. The power storage control unit 27 determines the voltage VWC_CHGON to be a value greater than the voltage VWC_DET and smaller than the voltage VWC_OK.

[0044] Voltage VWC_CMPL is a third voltage threshold of second voltage detection unit 25. Voltage VWC_CMPL is a voltage threshold used to determine whether to execute a complementary process in which the power stored in second power storage unit 26 is discharged to first power storage unit 23 when the power stored in first power storage unit 23 is less than voltage VWC_OK. For example, when the power stored in first power storage unit 23 is less than voltage VWC_OK and the voltage of second power storage unit 26 is equal to or greater than voltage VWC_CMPL (when it is expected that the power stored in first power storage unit 23 will reach voltage VWC_OK as a result of second power storage unit 26 executing the complementary process), power storage control unit 27 controls second power storage unit 26 to execute the complementary process. Furthermore, when the power stored in the first power storage unit 23 is less than the voltage VWC_OK and the voltage of the second power storage unit 26 is less than the voltage VWC_CMPL (when it is assumed that the power stored in the first power storage unit 23 will not reach the voltage VWC_OK even if the supplementary processing is performed by the second power storage unit 26), the power storage control unit 27 controls the second power storage unit 26 not to perform the above-mentioned supplementary processing.

[0045] The voltage VWC_CMPL may be a voltage threshold value that is determined by the power storage control unit 27 each time the power storage control unit 27 determines that the power stored in the first power storage unit 23 is less than the voltage VWC_OK, or may be a fixed voltage threshold value. For example, the power storage control unit 27 determines the voltage VWC_CMPL based on the amount of power generated by the power generation element 21, the power stored in the first power storage unit 23 and the second power storage unit 26, and the capacitances of the first power storage unit 23 and the second power storage unit 26. The power storage control unit 27 determines the voltage VWC_CMPL to be a value that is greater than the voltage VWC_DET and smaller than the voltage VWC_OK.

[0046] [Circuit configuration] Next, the circuit configuration of the rotation detector 1 according to the embodiment will be described with reference to Figures 3 to 6. In Figures 3 to 6, some components are shown as functional blocks.

[0047] Fig. 3 is a diagram showing a first circuit configuration of a rotation detector 1 according to an embodiment. Note that, of the rotation detector 1 shown in Fig. 3, components that are the same as those shown in Fig. 1 are assigned the same reference numerals. Also, Fig. 3 will mainly explain points that are not explained in Fig. 1.

[0048] As shown in FIG. 3, the rotation detector 1 includes a magnet 10, a power generating circuit 20, a power supply unit 30, and a rotational position detection unit 40.

[0049] Power generation circuit 20 includes power generation element 21, voltage detector 221, voltage detector 222, power storage unit 231, switch 241, voltage detector 251, power storage unit 261, power storage control unit 27, rectifier 28, and discharge circuit 29. Of the three voltage detectors, voltage detectors 221 and 222 correspond to first voltage detection unit 22 shown in FIG. 1, and voltage detector 251 corresponds to second voltage detection unit 25 shown in FIG. 1. Of the two power storage units, power storage unit 231 corresponds to first power storage unit 23 shown in FIG. 1, and power storage unit 261 corresponds to second power storage unit 26 shown in FIG. 1. Switch 241 corresponds to switch 24 shown in FIG. 1.

[0050] The voltage detector 221 detects the voltage in the wiring connecting the discharge circuit 29 and the power storage unit 231, that is, the voltage VWC generated by the power generation element 21. The voltage detector 221 outputs the value of the voltage VWC, a first voltage threshold VWC_DET, and a second voltage threshold VWC_OK to the power storage control unit 27.

[0051] The voltage detector 222 detects the voltage Vstg1 of the power storage unit 231 and the voltage Vchg1 of the power storage unit 231. The voltage detector 222 also outputs the value of the voltage Vstg1 or the value of the voltage Vchg1, the second voltage threshold VWC_OK, and the fourth voltage threshold VWC_CHGON to the power storage control unit 27. The voltage Vstg1 is a voltage due to charges stored in the power storage unit 231 due to power generation by the power generation element 21. The voltage Vchg1 is a voltage due to charges transferred between the power storage unit 231 and the power storage unit 261 during charging and discharging.

[0052] The power storage unit 231 is a fixed capacitance capacitor. One end of the power storage unit 231 is connected to the output of the rectifier 28, and the other end of the power storage unit 231 is connected to the ground.

[0053] The switch 241 is provided on a wiring that electrically connects the power storage unit 231 and the power storage unit 261, and switches on and off based on a signal output from the power storage control unit 27. The switch 241 is operated by the power VLDO supplied by the power supply unit 30.

[0054] The voltage detector 251 detects the voltage in the wiring connecting the switch 241 and the power storage unit 261, that is, the voltage of the power storage unit 261. Specifically, the voltage detector 251 detects the voltage Vstg2 of the power storage unit 261 and the voltage Vchg2 of the power storage unit 261. The voltage detector 251 also outputs the value of the voltage Vstg2 or the value of the voltage Vchg2 and a third voltage threshold VWC_CMPL to the power storage control unit 27. The voltage Vstg2 is a voltage due to the charge stored in the power storage unit 261. The voltage Vchg2 is a voltage due to the charge transferred between the power storage unit 231 and the power storage unit 261 during charging and discharging.

[0055] The power storage unit 261 is a fixed-capacitance capacitor. One end of the power storage unit 261 is connected to the switch 241, and the other end of the power storage unit 261 is connected to the ground.

[0056] The power storage control unit 27 outputs a signal to the switch 241 based on the values ​​output by the first voltage detection unit 22 (i.e., voltage detectors 221 and 222) and the second voltage detection unit 25 (i.e., voltage detector 251) and the multi-rotation processing signal MSC output by the information processing unit 42, to control the charging and discharging of the power storage units 231 and 261. The power storage control unit 27 operates using the power VLDO supplied by the power supply unit 30.

[0057] The rectifier 28 is connected to the power generating element 21 and performs full-wave rectification of the current generated by the power generating element 21. The current after rectification by the rectifier 28 is used to store power in the power storage unit 231.

[0058] Discharge circuit 29 is a processing circuit that discharges the power stored in power storage unit 231. Discharge circuit 29 is configured, for example, with a switch that discharges the power stored in power storage unit 231 by short-circuiting power storage unit 231 and ground.

[0059] The rotational position detection unit 40 detects the rotational position of the rotating shaft 11, and includes a magnetic sensor 41 and an information processing unit 42. The rotational position detection unit 40 operates using the power VLDO supplied by the power supply unit 30.

[0060] 3, the rotation detector 1 may have an IC section 50 in which the voltage detector 221, rectifier 28, and discharge circuit 29 of the power generation circuit 20, the power supply section 30, and the information processing section 42 of the rotation position detection section 40 are implemented in a single integrated circuit (multi-rotation IC). Note that the above-mentioned components do not have to be implemented in a single integrated circuit. In other words, the IC section 50 may be configured as a discrete circuit.

[0061] Furthermore, the power supply unit 30 may supply power to circuits other than the circuits described above (for example, the discharge circuit 29, etc.).

[0062] Furthermore, the power supply unit 30 does not need to supply power to the switch 241 (i.e., the switch 24) and the power storage control unit 27. For example, the switch 241 and the power storage control unit 27 may operate by receiving power supply from another DC power source or the like.

[0063] FIG. 4 is a diagram showing a second circuit configuration of the rotation detector 1 according to the embodiment. The same aspects of the rotation detector 1 shown in FIG. 4 as those shown in FIG. 3 will not be described, and differences from the rotation detector 1 shown in FIG. 3 will be mainly described. The reference numerals of the components shown in FIG. 4 are suffixed with "a" or "b." This distinction is made for ease of understanding, and components with the same reference numerals have the same basic operation. Similarly, the reference numerals of the control signals output from the voltage detectors 221a, 222a, 221a, and 222b and the information processing units 42a and 42b to the power storage control unit 27a are suffixed with "a" or "b" for ease of understanding.

[0064] As shown in Fig. 4, the rotation detector 1 is composed of a rotation detector 1a and a rotation detector 1b. The rotation detector 1 shown in Fig. 4 differs from the rotation detector 1 shown in Fig. 3 in that the rotation detector 1 is composed of a single power storage unit 261a that is shared by multiple rotation detectors. Note that Fig. 4 illustrates an example in which the rotation detector 1 is composed of two rotation detectors, but the present invention is not limited to this and may be composed of three or more rotation detectors.

[0065] The rotation detector 1a includes a magnet 10a, a power generating circuit 20a, a power supply unit 30a, and a rotational position detection unit 40a.

[0066] Power generation circuit 20a includes power generation element 21a, voltage detector 221a, voltage detector 222a, power storage unit 231a, switch 241a, voltage detector 251a, power storage unit 261a, power storage control unit 27a, rectifier 28a, and discharge circuit 29a. Of the three voltage detectors, voltage detector 221a and voltage detector 222a correspond to first voltage detection unit 22 shown in FIG. 1, and voltage detector 251a corresponds to second voltage detection unit 25 shown in FIG. 1. Of the two power storage units, power storage unit 231a corresponds to first power storage unit 23 shown in FIG. 1, and power storage unit 261a corresponds to second power storage unit 26 shown in FIG. 1. Switch 241a corresponds to switch 24 shown in FIG. 1.

[0067] The voltage detector 221a outputs the value of the voltage VWCa, the first voltage threshold VWC_DETa, and the second voltage threshold VWC_OKa to the power storage control unit 27a.

[0068] The voltage detector 222a detects the voltage Vstg1a of the power storage unit 231a before the power storage unit 231a supplies power to the power supply unit 30a and after the power storage unit 231a supplies power to the power supply unit 30a. The voltage detector 222a also detects the voltage Vchg1a of the power storage unit 231a after the power storage unit 231a discharges power to the power storage unit 261a or after the power storage unit 261a discharges power to the power storage unit 231a. The voltage detector 222a outputs the value of the voltage Vstg1a or the value of the voltage Vchg1a, the second voltage threshold VWC_OKa, and the fourth voltage threshold VWC_CHGONa to the power storage control unit 27a.

[0069] The switch 241a operates using the power VLDO1. Details of the power VLDO1 will be described later.

[0070] The voltage detector 251a outputs the value of the voltage Vstg2 or the value of the voltage Vchg2 and the third voltage threshold VWC_CMPL to the power storage control unit 27a.

[0071] One end of the power storage unit 261a is connected to the switch 241a and the switch 241b of the rotation detector 1b, and the other end of the power storage unit 261a is connected to the ground.

[0072] The power storage control unit 27a outputs a signal to the switch 241a based on the values ​​output by the first voltage detection unit 22 (i.e., voltage detectors 221a and 222a) of the rotation detector 1a and the second voltage detection unit 25 (i.e., voltage detector 251a) of the rotation detector 1a, and the multi-rotation processing signal MSCa output by the information processing unit 42a, to control the charging and discharging of the power storage units 231a and 261a. The power storage control unit 27a operates using power VLDO1.

[0073] The power storage control unit 27a outputs a signal to the switch 241b of the rotation detector 1b based on the values ​​output by the first voltage detection unit 22 (i.e., voltage detectors 221b and 222b) of the rotation detector 1b and the second voltage detection unit 25 (i.e., voltage detector 251a) of the rotation detector 1a, and the multi-rotation processing signal MSCb output by the information processing unit 42b of the rotation detector 1b, to control the charging and discharging of the power storage units 231b and 261a of the rotation detector 1b.

[0074] The power supply unit 30a outputs a constant voltage VLDO2 using, for example, the ground potential as a reference potential and the voltage across the capacitor of the power storage unit 231a as an input voltage.

[0075] The rotational position detection unit 40a operates using the power VLDO2 supplied by the power supply unit 30a. Furthermore, the information processing unit 42a of the rotational position detection unit 40a outputs a multi-rotation processing signal MSCa to the power storage control unit 27a and the magnetic sensor 41a based on information input from the magnetic sensor 41a.

[0076] The rotation detector 1a may also have an IC unit 50a in which the voltage detector 221a, rectifier 28a, and discharge circuit 29a of the power generation circuit 20a, the power supply unit 30a, and the information processing unit 42a of the rotation position detection unit 40a are implemented in a single integrated circuit (multi-rotation IC). Note that the above-mentioned components do not have to be implemented in a single integrated circuit. In other words, the IC unit 50a may be configured as a discrete circuit.

[0077] The rotation detector 1b includes a magnet 10b, a power generating circuit 20b, a power supply unit 30b, and a rotational position detecting unit 40b.

[0078] The power generation circuit 20b differs from the power generation circuit 20 shown in FIG. 3 in that it does not include a voltage detector 251 (i.e., second voltage detection unit 25), a power storage unit 261, and a power storage control unit 27. That is, the power generation circuit 20b differs from the power generation circuit 20 shown in FIG. 3 in that it does not include the second power storage unit 26 shown in FIG. 1. The power generation circuit 20b also includes a power generation element 21b, a voltage detector 221b, a voltage detector 222b, a power storage unit 231b, a switch 241b, a rectifier 28b, and a discharge circuit 29b. The voltage detector 221b and the voltage detector 222b correspond to the first voltage detection unit 22 shown in FIG. 1. The power storage unit 231b corresponds to the first power storage unit 23 shown in FIG. 1. The switch 241b corresponds to the switch 24 shown in FIG. 1.

[0079] The voltage detector 221b outputs the value of the voltage VWCb, the first voltage threshold VWC_DETb, and the second voltage threshold VWC_OKb to the power storage control unit 27a.

[0080] The voltage detector 222b detects the voltage Vstg1b of the power storage unit 231b before the power storage unit 231b supplies power to the power supply unit 30b and after the power storage unit 231b supplies power to the power supply unit 30b. The voltage detector 222b also detects the voltage Vchg1b of the power storage unit 231b after the power storage unit 231b discharges power to the power storage unit 261a or after the power storage unit 261a discharges power to the power storage unit 231b. The voltage detector 222b outputs the value of the voltage Vstg1b or the value of the voltage Vchg1b, the second voltage threshold VWC_OKb, and the fourth voltage threshold VWC_CHGONb to the power storage control unit 27a.

[0081] The switch 241b switches on and off based on a signal output from the power storage control unit 27a. The switch 241b operates using the power VLDO1.

[0082] The power supply unit 30b outputs a constant voltage VLDO3 using, for example, the ground potential as a reference potential and the voltage across the capacitor of the power storage unit 231b as an input voltage.

[0083] The rotational position detection unit 40b operates using the power VLDO3 supplied by the power supply unit 30b. Furthermore, the information processing unit 42b of the rotational position detection unit 40b outputs a multi-rotation processing signal MSCb to the power storage control unit 27a and the magnetic sensor 41b based on information input from the magnetic sensor 41b.

[0084] Furthermore, the rotation detector 1b may have an IC unit 50b in which the voltage detector 221b, rectifier 28b, and discharge circuit 29b of the power generation circuit 20b, the power supply unit 30b, and the information processing unit 42b of the rotation position detection unit 40b are implemented in a single integrated circuit (multi-rotation IC). Note that the above-mentioned components do not have to be implemented in a single integrated circuit. In other words, the IC unit 50b may be configured as a discrete circuit.

[0085] Furthermore, the rotation detector 1a supplies the power with the higher voltage, between the power VLDO2 supplied by the power supply unit 30a and the power VLDO3 supplied by the power supply unit 30b, as the power VLDO1 to each component of the rotation detector 1a and the rotation detector 1b.

[0086] According to the circuit configuration of the rotation detector 1 as shown in FIG. 4, the second power storage unit 26 (i.e., 261a) is configured as a single unit shared by multiple rotation detectors, so that charging of the second power storage unit 26 can be performed more stably.

[0087] Fig. 5 is a diagram showing a third circuit configuration of the rotation detector 1 according to the embodiment. Note that, of the rotation detector 1 shown in Fig. 5, explanation of the same points as the rotation detector 1 shown in Fig. 3 will be omitted, and the explanation will focus on the points that differ from the rotation detector 1 shown in Fig. 3.

[0088] The rotation detector 1 shown in Fig. 5 and the rotation detector 1 shown in Fig. 3 differ in the circuit configuration of the power generation circuit 20. Specifically, the power generation circuit 20 shown in Fig. 5 differs from the power generation circuit 20 shown in Fig. 3 in that it includes a switch 242 and a power storage unit 262. Note that the power storage unit 261 and the power storage unit 262 correspond to the second power storage unit 26 shown in Fig. 1. Also, the switch 241 and the switch 242 correspond to the switch 24 shown in Fig. 1.

[0089] The switch 242 is a switch such as a mechanical relay that switches the electrical connection between the power storage unit 261 and the power storage unit 262. The switch 242 is provided on a circuit that electrically connects the power storage unit 261 and the power storage unit 262, and is switched on and off based on a signal output by the power storage control unit 27. The switch 242 is operated by the power VLDO supplied by the power supply unit 30.

[0090] The power storage unit 262 is a fixed capacitance capacitor. One end of the power storage unit 262 is connected to the switch 242, and the other end of the power storage unit 262 is connected to the ground.

[0091] The power storage control unit 27 outputs signals to the switches 241 and 242 based on the values ​​output by the first voltage detection unit 22 (i.e., voltage detectors 221 and 222) and the second voltage detection unit 25 (i.e., voltage detector 251) and the multi-rotation processing signal MSC output by the information processing unit 42, thereby controlling the charging and discharging of the power storage unit 231, the power storage unit 261, and the power storage unit 262.

[0092] 5, rotation detector 1 has second power storage unit 26 (i.e., 261 and 262) that is configured with a plurality of fixed-capacitance capacitors, and therefore the apparent capacitance of second power storage unit 26 can be changed according to the power that first power storage unit 23 can discharge to second power storage unit 26. As a result, more power is stored in second power storage unit 26, and second power storage unit 26 can supply more power to first power storage unit 23.

[0093] Fig. 6 is a diagram showing a fourth circuit configuration of the rotation detector 1 according to the embodiment. Note that, of the rotation detector 1 shown in Fig. 6, explanation of the same points as the rotation detector 1 shown in Fig. 3 will be omitted, and the explanation will focus on the points that differ from the rotation detector 1 shown in Fig. 3.

[0094] The rotation detector 1 shown in Fig. 6 and the rotation detector 1 shown in Fig. 3 differ in the circuit configuration of the power generation circuit 20. Specifically, the power generation circuit 20 shown in Fig. 6 differs from the power generation circuit 20 shown in Fig. 3 in that the power storage unit 261 in Fig. 3 is replaced with a power storage unit 263. The power storage unit 263 corresponds to the second power storage unit 26 shown in Fig. 1.

[0095] The power storage unit 263 is a variable capacitance capacitor. One end of the power storage unit 263 is connected to the switch 241, and the other end of the power storage unit 263 is connected to the ground.

[0096] Voltage detector 251 detects the voltage in the wiring connecting switch 241 and power storage unit 263, that is, the voltage of power storage unit 263. Voltage detector 251 detects voltage Vstg2 of power storage unit 263 before power storage unit 231 discharges power to power storage unit 263 or before power storage unit 263 discharges power to power storage unit 231. Voltage detector 251 also detects voltage Vchg2 of power storage unit 263 after power storage unit 231 discharges power to power storage unit 263 or after power storage unit 263 discharges power to power storage unit 231.

[0097] 6, the circuit configuration of the rotation detector 1 includes second power storage unit 26 (i.e., 263) configured with a variable capacitance capacitor, and therefore the apparent capacitance of second power storage unit 26 can be changed according to the power stored in first power storage unit 23 and second power storage unit 26. This allows second power storage unit 26 to supply power to first power storage unit 23 more flexibly.

[0098] 3 to 6 may include, for example, an oscillator, which supplies an operating clock to the power storage control unit 27 and the information processing unit .

[0099] In the circuit configuration of the rotation detector 1 shown in FIGS. 3 to 6, the second power storage unit 26 may be formed from a battery.

[0100] In the circuit configuration of the rotation detector 1 shown in FIGS. 3 to 6, the second power storage unit 26 may store power supplied from an external source in addition to the power generated by the power generating element 21.

[0101] [Operation] Next, the operation of the rotation detector 1 according to this embodiment will be described.

[0102] FIG. 7 is a flowchart showing the operation of the rotation detector 1 according to the embodiment.

[0103] First, the power generating element 21 generates a power generating pulse in accordance with the rotation of the magnet 10 (step S101).

[0104] The power storage control unit 27 waits for stabilization of the internal operation (i.e., waits until the clock output by the oscillator stabilizes), and supplies the power generated by the power generating element 21 to the power supply unit 30 (step S102). Specifically, the power storage control unit 27 confirms that the value of the voltage VWC is greater than the first voltage threshold VWC_DET, and supplies the power generated by the power generating element 21 to the power supply unit 30. Note that in step S102, the power storage control unit 27 turns off the switch 24 by default.

[0105] The power storage control unit 27 determines whether the power generation by the power generating element 21 in step S101 is normal based on the value of the voltage VWC and the second voltage threshold VWC_OK (step S103). That is, in step S103, the power storage control unit 27 determines whether the value of the voltage VWC is greater than the second voltage threshold VWC_OK.

[0106] When it is determined in step S103 that power generation is not normal (No in step S103), power storage control unit 27 calculates the voltage Vstg1 of first power storage unit 23, the voltage Vstg2 of second power storage unit 26, and the third voltage threshold VWC_CMPL.<Vstg2、かつ、Vstg2> It is determined whether the condition VWC_CMPL is satisfied (step S104).

[0107] When it is determined that the condition in step S104 is satisfied (Yes in step S104), the power storage control unit 27 turns on the switch 24 to control the complementation of the voltage of the first power storage unit 23 (i.e., the complementation process by the second power storage unit 26) (step S105). In step S105, the power storage control unit 27 controls the complementation process by the second power storage unit 26 so that the voltage Vstg1 of the first power storage unit 23 becomes larger than the second voltage threshold VWC_OK. After step S105, the rotation detector 1 executes the operation again from step S103.

[0108] When it is determined that the condition in step S104 is not satisfied (No in step S104), the power storage control unit 27 turns off the switch 24 (step S113).

[0109] After step S113, power storage control unit 27 discharges the power stored in first power storage unit 23 from discharge circuit 29 to the ground (step S114). The operation in step S114 corresponds to a discharge process.

[0110] Furthermore, when it is determined in step S103 that power generation is normal (Yes in step S103), the power storage control unit 27 turns off the switch 24 or keeps the switch 24 turned off (step S106).

[0111] The information processing unit 42 outputs the multiple rotation processing signal MSC to the power storage control unit 27 (step S107).

[0112] The power storage control unit 27 calculates the fourth voltage threshold VWC_CHGON (step S108). In step S108, the power storage control unit 27 calculates the fourth voltage threshold VWC_CHGON based on, for example, the voltage Vstg1 of the first power storage unit 23, the voltage Vstg2 of the second power storage unit 26, and the capacitance between the first power storage unit 23 and the second power storage unit 26 after the first power storage unit 23 stops supplying power to the power supply unit 30.

[0113] The power storage control unit 27 determines whether the conditions Vstg1>Vstg2 and Vstg1>VWC_CHGON are satisfied based on the value of the voltage Vstg1 of the first power storage unit 23, the value of the voltage Vstg2 of the second power storage unit 26, and the fourth voltage threshold VWC_CHGON (step S109).

[0114] If it is determined in step S109 that the condition is not satisfied (No in step S109), the process proceeds to step S113. Note that the operations from step S113 onwards are the same as those described above, and therefore the explanation will be omitted.

[0115] When it is determined that the condition in step S109 is satisfied (Yes in step S109), power storage control unit 27 turns on switch 24 and controls so as to charge second power storage unit 26 using a portion of the power remaining in first power storage unit 23 (step S110).

[0116] Power storage control unit 27 determines whether or not the condition Vchg1=Vchg2 is satisfied based on the value of voltage Vchg1 of first power storage unit 23 and the value of voltage Vchg2 of second power storage unit 26 (step S111).

[0117] When it is determined that the condition in step S111 is not satisfied (No in step S111), power storage control unit 27 determines whether the charging time from first power storage unit 23 to second power storage unit 26 has exceeded the set time of a timer (step S112).

[0118] When it is determined that the charging time from first power storage unit 23 to second power storage unit 26 has not elapsed the set time of the timer (No in step S112), power storage control unit 27 continues charging second power storage unit 26.

[0119] If it is determined that the condition in step S111 is satisfied (Yes in step S111), or if it is determined that the charging time from first power storage unit 23 to second power storage unit 26 has exceeded the timer set time (Yes in step S112), the process proceeds to step S113. Note that the operations from step S113 onwards are the same as those described above, and therefore description thereof will be omitted.

[0120] The power storage control unit 27 controls the power supply from the first power storage unit 23 to the power supply unit 30 during the period from when the power generation element 21 starts generating power (step S101) to when the discharge circuit 29 performs the discharge process (step S114). For example, the power storage control unit 27 may perform control to stop the power supply from the first power storage unit 23 to the power supply unit 30 at the timing when the first power storage unit 23 has supplied a predetermined amount of power to the power supply unit 30, or may control the power supply from the first power storage unit 23 to the power supply unit 30 in accordance with the output of the multi-rotation processing signal MSC by the information processing unit 42.

[0121] Furthermore, the third voltage threshold VWC_CMPL in step S104 may be a voltage threshold that is set each time based on the power generation voltage VWC of the power generating element 21, the voltage Vstg1 of the power stored in the first power storage unit 23, the voltage Vstg2 of the power stored in the second power storage unit 26, and the capacitances of the first power storage unit 23 and the second power storage unit 26, or may be a fixed voltage threshold. Furthermore, the power storage control unit 27 determines the third voltage threshold VWC_CMPL to be a value greater than the first voltage threshold VWC_DET and smaller than the second voltage threshold VWC_OK.

[0122] Moreover, the power storage control unit 27 may execute the operation of step S106 only when the operation of step S105 has been executed.

[0123] Furthermore, power storage control unit 27 may keep switch 24 in the ON state without executing step S106, based on the value and capacitance of voltage Vstg1 of first power storage unit 23 and the value and capacitance of voltage Vstg2 of second power storage unit 26. That is, power storage control unit 27 may perform control in step S108 to supply power from first power storage unit 23 and second power storage unit 26 to power supply unit 30.

[0124] Moreover, the operations in step S103 and steps S106 to S107 correspond to the rotation position detection process.

[0125] 7, in steps S107 to S109, power storage control unit 27 maintains voltage Vstg1 of first power storage unit 23 to be equal to or higher than the operating voltages of power generation circuit 20 and rotational position detection unit 40. At this time, voltage VLDO of the power supplied by power supply unit 30 is, for example, 1.8V to 1.9V.

[0126] Furthermore, in step S108, power storage control unit 27 calculates fourth voltage threshold VWC_CHGON, for example, between steps S109 and S112, so that voltage Vstg1 of first power storage unit 23 is equal to or higher than the operating voltage of power generation circuit 20 and rotational position detection unit 40. At this time, voltage VLDO of the power supplied by power supply unit 30 is, for example, 1.8V to 1.9V.

[0127] Furthermore, in step S111, the voltages Vchg1 and Vchg2 do not need to be completely equal to each other. For example, the power storage control unit 27 may determine that the condition in step S111 is met if the voltage Vchg1 is within a range of ±0.1 V with respect to the voltage Vchg2.

[0128] As explained above, the rotation detector 1 includes the second storage unit 26 that stores a portion of the power remaining in the first storage unit 23 at the end of the rotation position detection process before the first storage unit 23 discharges the power to the outside in the discharge process. Therefore, when the power generated by the power generating element 21 does not reach the voltage required for the operation of the rotation detector 1 and the power stored in the first storage unit 23 is insufficient for the power required for the rotation position detection process, the shortfall in power can be supplemented by the power stored in the second storage unit 26.

[0129] Furthermore, when the power stored in first power storage unit 23 is less than the predetermined power for executing the rotational position detection process, power storage control unit 27 executes a supplementary process in which the power stored in second power storage unit 26 is discharged to first power storage unit 23, thereby raising the power supplied from first power storage unit 23 to power supply unit 30 to the predetermined power. This allows power storage control unit 27 to supply the power of second power storage unit 26 to first power storage unit 23 to supplement the power of first power storage unit 23, so that rotation detector 1 can execute the rotational position detection process even when the voltage of the power generated by power generating element 21 is low.

[0130] Next, a specific example of the operation of the rotation detector 1 described with reference to FIG. 7 will be described with reference to FIG.

[0131] Fig. 8 is a timing chart showing a specific example of the operation of the rotation detector 1 according to the embodiment. Fig. 8 shows an example of the timing of each operation when power is normally generated by the power generating element 21. Below, an example of the operation when the information processing unit 42 of the rotational position detection unit 40 executes the rotational position detection process using the power generated by the power generating element 21 of the power generating circuit 20 will be described. Therefore, in the following explanation, unless otherwise specified, the rotational position detection process involving the power generating circuit 20 and the rotational position detection unit 40 will be described.

[0132] "Vstg1" in FIG. 8 shows the time change of voltage Vstg1 of first power storage unit 23. "Vstg2" in FIG. 8 shows the time change of voltage Vstg2 of second power storage unit 26. "Vstg2" in FIG. 8 shows the voltage change (initial value is 0V) at the timing when power generation circuit 20 starts the first power generation and the voltage change at the timing when power generation circuit 20 starts the nth power generation. "OSC" in FIG. 8 schematically shows the oscillator output. Specifically, the period from when the oscillator outputs a clock until the clock stabilizes is shown by a rectangle with diagonal lines, and the period when the oscillator outputs a stable clock is shown by a rectangle with vertical lines. "Multi-rotation processing signal" in FIG. 8 shows the output of multi-rotation processing signal MSC by information processing unit 42 of rotation position detection unit 40. Specifically, the period when the output is high is the period when information processing unit 42 outputs multi-rotation processing signal MSC. The "switch" in Fig. 8 indicates a control signal for controlling the on / off of the switch 24. Specifically, when the control signal is high, the switch 24 is on, and when the control signal is low, the switch 24 is off. In the timing chart shown in Fig. 8, the time from time t0 to time t6 is, for example, approximately 70 μs. Fig. 8 also describes the case where the nth power generation by the power generating element 21 has started.

[0133] The operation of the rotation detector 1 will be described below with reference to FIG.

[0134] First, at time t0, when the rotating shaft 11 rotates while each circuit of the rotation detector 1 (in the example shown in FIG. 3, voltage detector 221, voltage detector 222, voltage detector 251, power storage control unit 27, and information processing unit 42) is reset, the magnetic field applied to the power generating element 21 from magnet 10 changes, causing the power generating element 21 to generate electricity and voltage Vstg1 to start rising. This is the timing corresponding to step S101 in FIG. 7. As voltage Vstg1 rises, the voltage of the power VLDO also rises via power supply unit 30, and the power generating element 21 supplies power to each block of the rotation detector 1.

[0135] After time t0, the oscillator starts measuring time, triggered by power generation by the power generation element 21. The clock output by the oscillator stabilizes before time t1. During this period, the power storage control unit 27 turns off the switch 24. This timing corresponds to step S102 in FIG. 7. Time t1 is set to the time at which the voltage Vstg1 reaches the second voltage threshold VWC_OK when power generation by the power generation element 21 is normal.

[0136] At time t1, the power storage control unit 27 determines whether the voltage Vstg1 has reached the second voltage threshold VWC_OK (for example, 2.6 V). This timing corresponds to step S103 in Fig. 7. In the example shown in Fig. 8, the voltage Vstg1 reaches the second voltage threshold VWC_OK at time t1, and therefore the power storage control unit 27 determines Yes in step S103.

[0137] From time t2 to time t3, information processing unit 42 of rotational position detection unit 40 outputs multi-rotation processing signal MSC to power storage control unit 27. The time from time t2 to time t3 is, for example, approximately 15 μs. Furthermore, from time t2 to time t3, the power stored in first power storage unit 23 is consumed largely by each block of rotation detector 1, particularly by rotational position detection unit 40, and therefore voltage Vstg1 of first power storage unit 23 decreases significantly. This is the timing corresponding to step S107 in FIG. 7.

[0138] From time t3 to time t4, the power storage control unit 27 calculates the fourth voltage threshold VWC_CHGON, which corresponds to step S108 in FIG.

[0139] At time t4, power storage control unit 27 determines whether the conditions Vstg1>Vstg2 and Vstg1>VWC_CHGON are satisfied. In the example of FIG. 8 , these conditions are satisfied, so power storage control unit 27 turns on switch 24 during time Δt from time t4 to time t5, and controls second power storage unit 26 to be charged using a portion of the power remaining in first power storage unit 23. Time Δt is, for example, approximately 2 μs. The dotted areas shown for voltages Vstg1 and Vstg2 from time t4 to time t5 are figures that indicate the amount of power transferred from first power storage unit 23 to second power storage unit 26. The areas shown for voltages Vstg1 and Vstg2 are equal in area. At time t5, voltage Vchg1 indicated by voltage Vstg1 is equal to voltage Vchg2 indicated by voltage Vstg2, so power storage control unit 27 turns off switch 24 to terminate charging of second power storage unit 26. At this time, voltage Vchg2 is equal to voltage Vstg2. n+1 These timings correspond to steps S109 to S113 in FIG.

[0140] After time t6, voltage Vstg1 becomes 0 V. First power storage unit 23 discharges all remaining power at time t6 from discharge circuit 29 to ground. This timing corresponds to step S114 in FIG. 7. As a result, voltage Vstg1 decreases, returning to the state before power generation by power generation element 21. In other words, each circuit of rotation detector 1 is reset, allowing rotation detector 1 to perform rotation position detection processing more accurately.

[0141] If power storage control unit 27 determines at time t4 that the conditions Vstg1>Vstg2 and Vstg1>VWC_CHGON are not satisfied, switch 24 is not turned on, and second power storage unit 26 is not charged. In this case, voltage Vstg1 varies with time from time t4 to time t6 as indicated by the dashed line.

[0142] Furthermore, from time t5 to time t6, voltage Vstg1 and voltage Vstg2 gradually decrease because the power stored in first power storage unit 23 and second power storage unit 26 is naturally discharged.

[0143] Another specific example of the operation of the rotation detector 1 described with reference to FIG. 7 will be described with reference to FIG.

[0144] Fig. 9 is a timing chart showing another specific example of the operation of the rotation detector 1 according to the embodiment. Fig. 9 shows an example of the timing of each operation when power generation is not performed normally by the power generating element 21. Below, an example of the operation when the information processing unit 42 of the rotational position detection unit 40 executes the rotational position detection process using the power generated by the power generating element 21 of the power generating circuit 20 will be described. Therefore, in the following explanation, unless otherwise specified, the rotational position detection process involving the power generating circuit 20 and the rotational position detection unit 40 will be described.

[0145] 9, similarly to FIG. 8, "Vstg1," "Vstg2," "OSC," a "multi-rotation processing signal," and a "switch" are shown. Note that "Vstg1" is shown as a graph with a solid line and a dashed line. The solid line graph is a graph showing the change over time in the voltage of first power storage unit 23 when power generation element 21 does not normally generate power, and the dashed line graph is a graph showing the change over time in the voltage of first power storage unit 23 when power generation element 21 normally generates power. In the explanation of "Vstg1" in FIG. 9, the solid line graph will be mainly described. In addition, in the timing chart shown in FIG. 9, the time from time t0 to time t18 is, for example, approximately 60 μs. In addition, FIG. 9 explains the case where power generation element 21 generates power for the nth time.

[0146] Hereinafter, the operation of the rotation detector 1 will be described with reference to FIG.

[0147] First, at time t0, when the rotating shaft 11 rotates while each circuit of the rotation detector 1 (in the example shown in FIG. 3, voltage detector 221, voltage detector 222, voltage detector 251, power storage control unit 27, and information processing unit 42) is reset, the magnetic field applied to the power generating element 21 from magnet 10 changes, causing the power generating element 21 to generate electricity and the voltage Vstg1 to start rising. This is the timing corresponding to step S101 in FIG. 7.

[0148] After time t0, the oscillator starts measuring time, triggered by power generation by the power generation element 21. The clock output by the oscillator stabilizes before time t12. The power storage control unit 27 turns off the switch 24 during this period. This is the timing corresponding to step S102 in FIG. 7. Time t12 is set to the time at which the voltage Vstg1 reaches the second voltage threshold VWC_OK when power generation by the power generation element 21 is normal.

[0149] During a time Δt_vwcOK (power supply determination time) from time t11 to time t12, the power storage control unit 27 determines whether the voltage Vstg1 has reached the second voltage threshold VWC_OK (for example, 2.6 V). This timing corresponds to step S103 in Fig. 7. In the example shown in Fig. 9, the voltage Vstg1 does not reach the second voltage threshold VWC_OK from time t11 to time t12, and therefore the power storage control unit 27 determines No in step S103.

[0150] During a time Δt_vwccmplOK (voltage complement determination time) from time t12 to time t13, power storage control unit 27 determines whether or not to perform complementation of the voltage of first power storage unit 23. That is, power storage control unit 27 determines whether or not to perform complementation of the voltage of first power storage unit 23.<Vstg2、かつ、Vstg2> It is determined whether the condition VWC_CMPL is satisfied. This is the timing corresponding to step S104 in Fig. 7. In the example shown in Fig. 9, power storage control unit 27 determines to perform complementation of the voltage of first power storage unit 23.

[0151] During time Δt_vwccmplon (voltage complementation time) from time t13 to time t15, power storage control unit 27 turns on switch 24 to complement the voltage of first power storage unit 23. In the example shown in FIG. 9 , at time t14, voltage Vstg1 of first power storage unit 23 reaches second voltage threshold VWC_OK. At time t15, power storage control unit 27 stops complementing the voltage of first power storage unit 23. Time Δt_vwccmplon is, for example, approximately 2 μs. From time t13 to time t15, the dotted areas shown for voltages Vstg1 and Vstg2 are figures indicating the amounts of power transferred from second power storage unit 26 to first power storage unit 23. The areas shown for voltages Vstg1 and Vstg2 are equal in area. At time t15, Vchg1 indicated by voltage Vstg1 is equal to Vchg2 indicated by voltage Vstg2, so power storage control unit 27 turns off switch 24 to stop complementing the voltage of first power storage unit 23. These steps correspond to steps S105, S103, and S106 in FIG. 7.

[0152] As shown in the dashed line graph indicated by "SWITCH," power storage control unit 27 may adjust the time for turning on switch 24 depending on the operating status of rotation detector 1 and the power storage status of first power storage unit 23 and second power storage unit 26. In the example shown in FIG. 9, first power storage unit 23 and second power storage unit 26 may supply power to power supply unit 30.

[0153] From time t16 to time t17, information processing unit 42 of rotational position detection unit 40 outputs multi-rotation processing signal MSC to power storage control unit 27. The time from time t16 to time t17 is, for example, approximately 15 μs. Also, from time t16 to time t17, power storage control unit 27 supplies the power stored in first power storage unit 23 to power supply unit 30, so that voltage Vstg1 decreases. This is the timing corresponding to step S107 in FIG. 7.

[0154] From time t17 to time t18, power storage control unit 27 calculates fourth voltage threshold VWC_CHGON. Then, power storage control unit 27 determines whether or not the conditions Vstg1>Vstg2 and Vstg1>VWC_CHGON are satisfied. In the example of FIG. 9, the above conditions are not satisfied, so power storage control unit 27 does not charge second power storage unit 26 using part of the power remaining in first power storage unit 23. Furthermore, at time t18, power storage control unit 27 turns off switch 24. These timings correspond to steps S108 to S113 in FIG. 7.

[0155] After time t18, voltage Vstg1 becomes 0 V. First power storage unit 23 discharges all remaining power at time t18 from discharge circuit 29 to ground. This corresponds to step S114 in FIG. 7. As a result, voltage Vstg1 decreases, returning to the state before power generation by power generation element 21. In other words, each circuit of rotation detector 1 is reset, allowing rotation detector 1 to perform rotation position detection processing more accurately.

[0156] [effect] The rotation detector 1 according to this embodiment includes a magnet 10 that rotates together with a rotating shaft 11, a power generating circuit 20 having a power generating element 21 that generates power by utilizing the large Barkhausen effect caused by a change in the magnetic field due to the rotation of the magnet 10 together with the rotating shaft 11, a magnetic sensor 41 that detects the change in the magnetic field, an information processing unit 42 that detects the rotation position of the rotating shaft 11 using the power generating element 21 and the magnetic sensor 41, and a power supply unit 30 that supplies the power generated by the power generating element 21 to the magnetic sensor 41 and the information processing unit 42. The power generating circuit 20 includes a first power storage unit 23 that stores the power generated by the power generating element 21, and a second power storage unit 24 that detects the voltage generated by the power generating element 21. The device has a first voltage detection unit 22, a second storage unit 26 for storing power, a second voltage detection unit 25 that detects the voltage of the second storage unit 26, and a storage control unit 27 that controls the first storage unit 23 and the second storage unit 26, wherein the first storage unit 23 supplies a predetermined amount of power required for the rotational position detection process executed by the information processing unit 42 to the power supply unit 30, the storage control unit 27 controls the charging and discharging of the first storage unit 23 and the second storage unit 26 according to the voltages detected by the first voltage detection unit 22 and the second voltage detection unit 25, and the second storage unit 26 stores a portion of the power remaining in the first storage unit 23 at the end of the rotational position detection process before the first storage unit 23 discharges the power to the outside in a discharging process.

[0157] As a result, the rotation detector 1 includes second power storage unit 26 that stores a portion of the power remaining in first power storage unit 23 before first power storage unit 23 discharges to the outside in the discharge process at the end of the rotation position detection process, so that when the power generated by power generating element 21 does not reach the voltage required for the operation of the rotation detector 1 and the power stored in first power storage unit 23 is insufficient for the power required for the rotation position detection process, the shortfall in power can be supplemented with the power stored in second power storage unit 26. Therefore, the rotation detector 1 can perform a more stable rotation position detection process.

[0158] Furthermore, in the rotation detector 1 according to this embodiment, when the power stored in the first power storage unit 23 is less than the predetermined power for executing the rotation position detection process, the power storage control unit 27 executes a complementary process of discharging the power stored in the second power storage unit 26 to the first power storage unit 23, thereby increasing the power supplied by the first power storage unit 23 to the power supply unit 30 to the predetermined power.

[0159] As a result, power storage control unit 27 can supply power from second power storage unit 26 to first power storage unit 23 to supplement the power of first power storage unit 23, and therefore rotation detector 1 can perform the rotation position detection process even when the voltage of the power generated by power generation element 21 is low. Therefore, rotation detector 1 can perform a more stable rotation position detection process.

[0160] Furthermore, in rotation detector 1 according to the present embodiment, second power storage unit 26 is configured as a single unit shared by a plurality of rotation detectors.

[0161] As a result, second power storage unit 26 is configured as a single unit shared by a plurality of rotation detectors, and therefore rotation detector 1 can charge second power storage unit 26 more stably.

[0162] In rotation detector 1 according to the present embodiment, second power storage unit 26 is made up of a plurality of fixed capacitors or variable capacitors.

[0163] Since rotation detector 1 has second power storage unit 26 configured with a plurality of fixed-capacitance capacitors, it is possible to change the apparent capacitance of second power storage unit 26 in accordance with the power that first power storage unit 23 can discharge to second power storage unit 26. This increases the amount of power stored in second power storage unit 26, and therefore second power storage unit 26 can supply more power to first power storage unit 23. Therefore, rotation detector 1 can perform a more stable rotation position detection process.

[0164] Furthermore, since rotation detector 1 has second power storage unit 26 formed of a variable capacitor, it is possible to change the apparent capacitance of second power storage unit 26 according to the power stored in first power storage unit 23 and second power storage unit 26. This allows second power storage unit 26 to supply power to first power storage unit 23 more flexibly, and therefore rotation detector 1 can perform a more stable rotation position detection process.

[0165] In rotation detector 1 according to the present embodiment, the second power storage unit is formed of a battery.

[0166] Rotation detector 1 has second power storage unit 26, which is made up of a battery, and is therefore able to hold a larger amount of power. As a result, second power storage unit 26 optimally supplements the power of first power storage unit 23, allowing first power storage unit 23 to obtain the power necessary for the operation of rotation detector 1, and therefore rotation detector 1 can perform a more stable rotation position detection process.

[0167] Furthermore, in the rotation detector 1 according to this embodiment, the power storage control unit 27 controls the storage of power in the second power storage unit 26 and the complementary processing by the second power storage unit 26 based on the amount of electricity generated by the power generation element 21, the capacitance between the first power storage unit 23 and the second power storage unit 26, the amount of electricity stored in the first power storage unit 23 and the second power storage unit 26, and the timing of the rotation position detection processing.

[0168] The rotation detector 1 can charge the second storage unit 26 from the first storage unit 23 or supplement the first storage unit 23 from the second storage unit 26 depending on the amount of electricity generated by the power generation element 21, the capacitance between the first storage unit 23 and the second storage unit 26, and the amount of electricity stored in the first storage unit 23 and the second storage unit 26.

[0169] Furthermore, in the rotation detector 1 according to this embodiment, second power storage section 26 stores power generated by power generating element 21 as well as power supplied from the outside.

[0170] The second power storage unit 26 stores power supplied from an external source (for example, external power or a power source such as a battery) in addition to the power generated by the power generating element 21, and therefore can hold power more stably, which allows the rotation detector 1 to perform a more stable rotation position detection process.

[0171] (others) While the rotation detector according to the present disclosure has been described above based on the embodiments and modifications, the present disclosure is not limited to the above embodiments and modifications. The present disclosure also includes forms obtained by applying various modifications to the above embodiments and modifications that would occur to a person skilled in the art, and forms realized by arbitrarily combining the components and functions of the embodiments within the scope of the present disclosure.

[0172] For example, in the above embodiment, the first voltage detection unit 22 and the second voltage detection unit 25 are configured with comparators corresponding to the respective voltage thresholds, but this is not limited thereto. For example, the first voltage detection unit 22 may be a voltage detector that detects the voltage values ​​of the voltages VWC_DET, VWC_OK, and VWC_CHGON. The first voltage detection unit 22 outputs the voltage values ​​of the voltages VWC and Vstg1 at predetermined time intervals, for example. Furthermore, the second voltage detection unit 25 may be a voltage detector that detects the voltage value of the voltage VWC_CMPL. The second voltage detection unit 25 outputs the voltage value of the voltage Vstg2 at predetermined intervals, for example. In this case, the storage control unit 27 controls the supply of power from the first storage unit 23 to the power supply unit 30, the supply of power from the first storage unit 23 to the second storage unit 26, and the supply of power from the second storage unit 26 to the first storage unit 23 based on the voltage values ​​of the voltage VWC and voltage Vstg1 detected by the first voltage detection unit 22, the voltage Vstg2 detected by the second voltage detection unit 25, and each voltage threshold value.

[0173] In the above embodiment, the processes performed by specific processing units such as the power storage control unit 27 and the information processing unit 42 may be performed by other processing units. The order of multiple processes may be changed, or multiple processes may be performed in parallel.

[0174] In the above embodiment, all or part of the processing units such as the power storage control unit 27 and the information processing unit 42 may be configured with dedicated hardware, or may be realized by executing a software program suitable for each processing unit. Each processing unit may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a semiconductor memory.

[0175] Furthermore, the processing units such as the power storage control unit 27 and the information processing unit 42 may be configured with one or more electronic circuits. Each of the one or more electronic circuits may be a general-purpose circuit or a dedicated circuit.

[0176] The one or more electronic circuits may include, for example, a semiconductor device, an integrated circuit (IC), or a large-scale integration (LSI). The IC or LSI may be integrated on a single chip or on multiple chips. Although we refer to them as ICs or LSIs here, the names may vary depending on the degree of integration, and they may be called system LSIs, very large-scale integrations (VLSIs), or ultra-large-scale integrations (ULSIs). Also, field-programmable gate arrays (FPGAs), which are programmed after the LSI is manufactured, can be used for the same purpose.

[0177] Furthermore, the general or specific aspects of the present disclosure may be realized as a system, an apparatus, a method, an integrated circuit, or a computer program. Alternatively, the general or specific aspects may be realized as a computer-readable non-transitory recording medium such as an optical disk, a HDD, or a semiconductor memory on which the computer program is stored. Alternatively, the general or specific aspects of the present disclosure may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0178] Examples of the rotation detector according to the present disclosure described based on the above embodiment are shown below. The rotation detector according to the present disclosure is not limited to the following examples.

[0179] For example, a rotation detector according to a first aspect of the present disclosure includes a magnet that rotates together with a rotating shaft, a power generating circuit having a power generating element that generates power by utilizing the large Barkhausen effect caused by a change in a magnetic field due to the rotation of the magnet together with the rotating shaft, a magnetic sensor that detects the change in the magnetic field, an information processing unit that detects the rotation position of the rotating shaft using the power generating element and the magnetic sensor, and a power supply unit that supplies the power generated by the power generating element to the magnetic sensor and the information processing unit, and the power generating circuit includes a first power storage unit that stores the power generated by the power generating element, and a first power supply unit that detects a voltage generated by the power generating element. The power storage device includes a voltage detection unit, a second storage unit for storing power, a second voltage detection unit that detects the voltage of the second storage unit, and a storage control unit that controls the first storage unit and the second storage unit, wherein the first storage unit supplies the power supply unit with a predetermined amount of power required for the rotational position detection process executed by the information processing unit, the storage control unit controls charging and discharging of the first storage unit and the second storage unit according to the voltages detected by the first voltage detection unit and the second voltage detection unit, and the second storage unit stores a portion of the power remaining in the first storage unit before the first storage unit discharges the power to the outside in a discharging process at the end of the rotational position detection process.

[0180] Also, for example, a rotation detector according to a second aspect of the present disclosure is the rotation detector according to the first aspect, wherein when the power stored in the first power storage unit is less than the predetermined power for executing the rotation position detection process, the power storage control unit executes a complementary process to discharge the power stored in the second power storage unit to the first power storage unit, thereby increasing the power supplied by the first power storage unit to the power supply unit to the predetermined power.

[0181] Also, for example, a rotation detector according to a third aspect of the present disclosure is the rotation detector according to the first or second aspect, wherein the second power storage unit is configured as a single unit shared by a plurality of the rotation detectors.

[0182] Also, for example, a rotation detector according to a fourth aspect of the present disclosure is the rotation detector according to any one of the first to third aspects, wherein the second power storage unit is composed of a plurality of fixed capacitors or variable capacitors.

[0183] Furthermore, for example, a rotation detector according to a fifth aspect of the present disclosure is the rotation detector according to any one of the first to third aspects, wherein the second power storage unit is formed of a battery.

[0184] Furthermore, for example, a rotation detector according to a sixth aspect of the present disclosure is a rotation detector according to any one of the second to fifth aspects, wherein the power storage control unit controls the storage of power in the second power storage unit and the complementary processing by the second power storage unit based on the amount of electricity generated by the power generation element, the capacitance between the first power storage unit and the second power storage unit, the amount of electricity stored in the first power storage unit and the second power storage unit, and the timing of the rotation position detection processing.

[0185] Furthermore, for example, a rotation detector according to a seventh aspect of the present disclosure is a rotation detector according to any one of the first to sixth aspects, wherein the second power storage unit stores power supplied from an external source in addition to the power generated by the power generating element. [Industrial Applicability]

[0186] The rotation detector according to the present disclosure can be used to detect the rotation of the rotating shaft of a motor that rotates a load. [Explanation of symbols]

[0187] 1, 1a, 1b Rotation detector 10, 10a, 10b Magnets 11 Rotation axis 20, 20a, 20b Power generation circuit 21, 21a, 21b Power generating elements 22 First voltage detection unit 221, 221a, 221b, 222, 222a, 222b, 251, 251a voltage detectors 23 First storage unit 231, 231a, 231b, 261, 261a, 262, 263 Power storage unit 24, 241, 241a, 241b, 242 switches 25 Second voltage detection unit 26 Second storage unit 27, 27a Power storage control unit 28, 28a, 28b rectifier 29, 29a, 29b discharge circuit 30, 30a, 30b Power supply section 40, 40a, 40b Rotation position detection unit 41, 41a, 41b magnetic sensors 42, 42a, 42b Information processing section 50, 50a, 50b IC section

Claims

1. a power generating circuit having a magnet that rotates together with a rotating shaft, a power generating element that generates power by utilizing the large Barkhausen effect that occurs due to a change in a magnetic field caused by the rotation of the magnet together with the rotating shaft, a magnetic sensor that detects the change in the magnetic field, an information processing unit that detects the rotation position of the rotating shaft using the power generating element and the magnetic sensor, and a power supply unit that supplies power generated by the power generating element to the magnetic sensor and the information processing unit, The power generation circuit includes: a first power storage unit that stores the power generated by the power generation element; a first voltage detection unit that detects a voltage generated by the power generation element; a second power storage unit for storing power; a second voltage detection unit that detects a voltage of the second power storage unit; a power storage control unit that controls the first power storage unit and the second power storage unit, the first power storage unit supplies the power supply unit with a predetermined amount of power required for the rotational position detection process executed by the information processing unit; the power storage control unit controls charging and discharging of the first power storage unit and the second power storage unit in accordance with voltages detected by the first voltage detection unit and the second voltage detection unit; the second power storage unit stores a portion of the power remaining in the first power storage unit before the first power storage unit discharges the power to the outside in a discharging process at the end of the rotational position detection process; Rotation detector.

2. When the power stored in the first power storage unit is less than the predetermined power for executing the rotational position detection process, the power storage control unit executes a supplementary process of discharging the power stored in the second power storage unit to the first power storage unit, thereby increasing the power supplied from the first power storage unit to the power supply unit to the predetermined power. The rotation detector according to claim 1 .

3. the second power storage unit is configured as a single unit shared by the plurality of rotation detectors, 3. The rotation detector according to claim 1 or 2.

4. The second power storage unit is composed of a plurality of fixed capacitors or variable capacitors.

3. The rotation detector according to claim 1 or 2.

5. The second power storage unit is composed of a battery.

3. The rotation detector according to claim 1 or 2.

6. the power storage control unit controls the storage of power in the second power storage unit and the complementary process by the second power storage unit based on the amount of electricity generated by the power generation element, the capacitance between the first power storage unit and the second power storage unit, the amount of electricity stored in the first power storage unit and the second power storage unit, and a timing of the rotation position detection process. The rotation detector according to claim 2 .

7. The second power storage unit stores power supplied from an external source in addition to the power generated by the power generation element.

3. The rotation detector according to claim 1 or 2.

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