Portable machine and mode control method

Abstract

A portable machine (9) has a normal mode and a power saving mode as operation modes. When the portable machine (9) is in the normal mode, a controller (943) starts on the basis of the detection of vibration by an acceleration sensor (91), and measures the output voltage of a battery (93). If the output voltage is above a predetermined stop voltage greater than a discharge termination voltage, the controller (943) starts advertising by cooperation with an RF core (942). On the other hand, when the output voltage is equal to or less than a stop voltage, the controller (943) executes processing for shifting to the power saving mode, and stops the operation. The power saving mode is an operation mode in which the short-range communication function is disabled, and may be, for example, an operation mode in which the acceleration sensor (91) is stopped.

Description

Portable device, mode control method CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2023-125811 filed in Japan on August 1, 2023, and the contents of the original application are incorporated by reference in their entirety.

[0002] The present disclosure relates to a portable device that functions as a wireless door key.

[0003] Patent Literature 1 discloses a configuration in which, upon establishing a communication connection between a vehicle and a portable device via Bluetooth (registered trademark) Low Energy (hereinafter referred to as Bluetooth LE), the vehicle and the portable device start wireless communication for determining their positions. In Patent Literature 1, a plurality of sensors mounted on the vehicle and the portable device perform ranging communication using UWB (Ultra Wide Band) communication, thereby determining the position of the portable device relative to the vehicle. Patent Literature 2 also discloses a portable device that operates on a secondary battery such as a lithium-ion battery.

[0004] Japanese Patent No. 7085526 Japanese Patent Application Laid-Open No. 2019-131967

[0005] Compared to portable devices powered by primary batteries, portable devices powered by secondary batteries have the advantage of eliminating the need to replace the battery. However, secondary batteries can become over-discharged and become unable to be recharged. In order to extend the life of secondary batteries, it is preferable that the remaining battery power does not drop to the discharge cut-off voltage.

[0006] The present disclosure has been made in light of the above circumstances, and one of its objectives is to provide a technique for suppressing deterioration of a secondary battery in a portable device that operates on the secondary battery.

[0007] The portable device disclosed herein is a portable device that functions as a wireless key for a door and is powered by a secondary battery, and is equipped with a wireless communication unit for wirelessly communicating with a system that controls the locking status of the door, and a control unit that controls the wireless communication unit, and the control unit is configured to transmit an advertising signal, which is a wireless signal for communicating and connecting with the system, using the wireless communication unit, obtain data indicating the remaining power of the secondary battery, and change the operating mode of the portable device related to the transmission of the advertising signal based on the remaining power.

[0008] According to the above configuration, the transmission mode (e.g., frequency and transmission power) of the advertising signal is changed depending on the remaining power of the secondary battery, thereby reducing the risk of the secondary battery reaching an over-discharge state and suppressing deterioration of the secondary battery.

[0009] The mode control method included in the present disclosure is a mode control method executed by a portable device configured to operate on a secondary battery and function as a wireless door key, and includes transmitting, using a wireless communication unit, an advertising signal, which is a wireless signal for communicating with a system that controls the locking status of the door, obtaining the remaining power of the secondary battery, and changing the operating mode of the portable device related to the transmission of the advertising signal based on the remaining power.

[0010] According to the above mode control method, the transmission mode of the advertising signal is changed depending on the remaining power of the secondary battery, so that deterioration of the secondary battery can be suppressed.

[0011] Note that the symbols in parentheses in the claims indicate a correspondence with the specific means described in the embodiments described below as one aspect, and do not limit the technical scope of the present disclosure.

[0012] 1 is a diagram showing an overall view of a vehicle electronic key system; FIG. 2 is a block diagram of an in-vehicle system; FIG. 3 is a block diagram of a portable device; FIG. 4 is a block diagram showing the configuration of a wireless power receiving unit; FIG. 5 is a flowchart showing an example of the operation of a controller when wireless charging begins; FIG. 6 is a diagram showing an example of a user's operation for forcibly transitioning to a power saving mode; FIG. 7 is a sequence diagram showing the flow of communication between a vehicle and a portable device; FIG. 8 is a flowchart for explaining the operation of the controller when the portable device vibrates; FIG. 9 is a flowchart showing another example of the operation of the controller;

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments. The configurations disclosed below may be implemented with various modifications within the scope of the gist. Various modified examples may be implemented in appropriate combinations within the scope of no technical contradiction. The present disclosure also includes configurations that are not explicitly stated and are formed by combining multiple modified examples. In the following description, components having the same function may be assigned the same reference numerals, and specific descriptions thereof may be omitted. When only a portion of a configuration is mentioned, descriptions given elsewhere may apply to other parts.

[0014] <Overall Configuration> As shown in FIG. 1, the electronic key system for a vehicle according to this embodiment includes an in-vehicle system 10 and a portable device 9. The in-vehicle system 10 is a system mounted on the vehicle Hv. As shown in FIG. 2, the in-vehicle system 10 includes a position determination device 1 and multiple anchors 2. In the following description, the in-vehicle system 10 and the vehicle Hv may be interchangeable. The in-vehicle system 10 corresponds to a system that controls the locking state of the doors of the vehicle Hv.

[0015] The portable device 9 is a wireless communication terminal carried by a user. The portable device 9 is linked to the position determination device 1. That is, device information of the portable device 9 is registered in the position determination device 1. The device information includes a device identification number (hereinafter referred to as a device ID). The device ID may be a device address or a universally unique identifier (UUID), etc. Multiple portable devices 9 may be linked to the position determination device 1.

[0016] The position determination device 1 is a device that determines the position of the portable device 9 relative to the vehicle Hv. Both the position determination device 1 and the portable device 9 include a short-range communication module. The short-range communication module is a communication module that enables short-range communication. Here, short-range communication refers to communication that complies with a predetermined wireless communication standard with an actual communication distance of 5 m to 50 m, and at most approximately 100 m. The short-range communication may be Bluetooth (registered trademark) Low Energy (hereinafter, Bluetooth LE), Wi-Fi (registered trademark), or the like. In the following description and drawings, short-range communication may be referred to as SRWC (Short Range Wireless Communication). Furthermore, in this disclosure, a signal transmitted and received via short-range communication may be referred to as a short-range communication signal or an SRWC signal.

[0017] The operation of each part will be described below using an example in which short-range communication (i.e., SRWC) is performed using Bluetooth LE. Furthermore, the portable device 9 is set to operate as a peripheral in Bluetooth LE, and the position determination device 1 is set to act as a central. The roles of the portable device 9 and the position determination device 1 may be interchanged.

[0018] The anchor 2 is a wireless communication module for performing ranging communication with the portable device 9. In this disclosure, ranging communication refers to wireless communication for measuring the distance between communication devices. In this embodiment, the multiple anchors 2 and the portable device 9 are all configured to be able to perform ranging communication by UWB communication. UWB communication is wireless communication using the UWB-IR (Ultra Wide Band - Impulse Radio) method.

[0019] The anchor 2 and the portable device 9 are configured to be able to transmit and receive impulse-shaped radio waves (hereinafter referred to as impulse signals) used in UWB communication. The impulse signals used in UWB communication may be signals having an extremely short pulse width (e.g., 2 ns) and a bandwidth (i.e., ultra-wide bandwidth) of 500 MHz (strictly speaking, 499.2 MHz) or more. Hereinafter, UWB signals may be understood to mean signals exchanged in UWB communication.

[0020] In addition, the in-vehicle system 10 and the portable device 9 are configured to be capable of near-field communication (NFC). Here, NFC refers to communication over a distance of several centimeters to several tens of centimeters. NFC can also be called near-field communication, contactless communication, or touch communication. NFC corresponds to a communication method with a communication distance significantly shorter than SRWC. The communication distance of NFC may be one-tenth or less of SRWC. Specific standards for NFC may be ISO / IEC 18092 (NFCIP-1), ISO / IEC 21481 (NFCIP-2), ISO / IEC 14443, or ISO / IEC 18092. During NFC communication with the vehicle hybrid vehicle, the portable device 9 is configured to operate as a terminal that returns data in response to a request from the vehicle hybrid vehicle, i.e., as a passive device (so-called tag). The roles of the in-vehicle system 10 and the portable device 9 in NFC communication may be interchangeable.

[0021] <In-Vehicle System> As shown in FIG. 2 , the in-vehicle system 10 includes a position determination device 1, a plurality of anchors 2, and other devices such as a body ECU 3, an NFC reader 4, and a display 5. The position determination device 1 is connected to each of the plurality of anchors 2 via a dedicated communication cable. The position determination device 1 is also connected to the body ECU 3 via an in-vehicle network. The in-vehicle network is a communication network established within the vehicle Hv. The standard of the in-vehicle network may be any standard, such as Controller Area Network (CAN is a registered trademark), Ethernet (registered trademark), or FlexRay (registered trademark). The connection configuration between the devices may be changed as appropriate.

[0022] The position determination device 1 is an ECU that determines the device position in cooperation with the anchor 2. In this disclosure, the device position means the relative position of the portable device 9 with respect to the vehicle Hv. Determining the device position corresponds to determining the user's position. The term "device position" may be read as "user position." The position determination device 1 controls the operation of the anchor 2.

[0023] The position determination device 1 includes a processor 11, a memory 12, a storage 13, a wireless communication circuit 14, and an in-vehicle communication unit 15. The processor 11 may be a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The memory 12 may be a volatile storage medium such as a RAM (Random Access Memory). The storage 13 includes a non-volatile storage medium such as a flash memory. The storage 13 may store the device ID and anchor data of the portable device 9, and authentication data. The anchor data is data indicating the mounting positions of multiple anchors 2 in the vehicle Hv. The authentication data may be data (e.g., a key code) for authenticating the portable device 9.

[0024] The wireless communication circuit 14 is a short-range communication module built into the position determination device 1. The wireless communication circuit 14 includes an antenna for short-range communication, a transmitting / receiving circuit, and an SRWC controller. The transmitting / receiving circuit is a circuit that performs signal processing related to modulation and demodulation. The SRWC controller is a microcomputer that executes data processing related to short-range communication.

[0025] The wireless communication circuit 14 is supplied with power from the vehicle battery even while the driving power supply is set to off. The wireless communication circuit 14 periodically scans using the power supplied from the vehicle battery and attempts to connect with the portable device 9. Scanning means that the wireless communication circuit 14 is in a state where it can receive an SRWC signal. Upon receiving an advertising signal from the portable device 9, the wireless communication circuit 14 transmits a connection request to the portable device 9 and establishes a communication connection with the portable device 9.

[0026] The in-vehicle communication unit 15 is a circuit that allows the processor 11 to communicate with each of the multiple anchors 2. The in-vehicle communication unit 15 may also include a circuit that allows the processor 11 to communicate with other in-vehicle devices via an in-vehicle network. The in-vehicle communication unit 15 may include a PHY chip or the like that complies with the communication standard of the in-vehicle network.

[0027] Upon establishing a communication connection with the portable device 9, the position determination device 1 performs authentication processing in the SRWC. The authentication processing may be performed using a challenge-response method or the like. Furthermore, upon establishing a communication connection with the portable device 9, the position determination device 1 causes each anchor 2 to perform ranging communication with the portable device 9. The position determination device 1 acquires data indicating the results of the ranging communication (hereinafter, ranging result data) from each of the multiple anchors 2. The ranging result data includes the ID of the portable device 9 that performed the ranging and data indicating the distance from the anchor 2 to the portable device 9. In this disclosure, the value indicating the distance from the anchor 2 to the portable device 9, determined by ranging communication, may be referred to as a ranging value.

[0028] The position determination device 1 determines the distance from the vehicle Hv to the portable device 9 (hereinafter also referred to as the device distance) based on the distance measurement result data provided from each anchor 2. The position determination device 1 may determine the device distance by combining / integrating the distance measurement values ​​observed by multiple anchors 2. The device distance may be the minimum value of the distance measurement values ​​observed by the multiple anchors 2.

[0029] Furthermore, the position determination device 1 may determine whether the portable device 9 is located inside the vehicle, in a nearby area, or in another area based on the distance measurement result data provided from each anchor 2. The nearby area is an area outside the vehicle that is within a predetermined operating distance from the vehicle Hv. The operating distance may be set to 1.0 m, 1.5 m, 2.0 m, etc. The position determination device 1 may determine whether the portable device 9 is located in the nearby area by comparing the device distance with the operating distance. The position determination device 1 provides the body ECU 3 with the identified position information of the portable device 9.

[0030] As described above, the anchor 2 is a device for performing ranging communication with the portable device 9. The anchor 2 is configured to be able to perform UWB communication. The in-vehicle system 10 of this embodiment may include multiple anchors 2. The anchors 2 may be arranged at the left and right ends of the front bumper and the left and right ends of the rear bumper. The anchors 2 may be arranged near the driver's seat, on the ceiling inside the vehicle, in the trunk, etc. The configuration and performance of each anchor 2 may be substantially identical.

[0031] The anchor 2 includes an antenna for UWB communication, a transmitting / receiving circuit, and a UWB controller. The UWB controller is a microcomputer that executes processing related to ranging communication. The UWB controller generates ranging result data by performing ranging communication with the portable device 9, and transmits (reports) the ranging result data to the position determination device 1. An overview of ranging communication will be described later.

[0032] The body ECU 3 is an ECU (Electronic Control Unit) that controls body equipment such as headlights, door lock motors, and power window motors. The body ECU 3 controls unlocking / locking of doors based on (i) the presence of the portable device 9 in the vicinity area, (ii) the portable device 9 has been authenticated, and (iii) a predetermined user action has been performed.

[0033] Whether the portable device 9 is present in the vicinity area may be determined by referring to the determination result of the position determination device 1. Authentication of the portable device 9 is also performed by the position determination device 1. A user action for locking / unlocking may be touching a door handle or waving a foot over a detection area formed below the door. Controlling the unlocking / locking of the door corresponds to controlling the locking state of the vehicle Hv. The body ECU 3 may be considered an ECU that provides a passive entry function in cooperation with the position determination device 1. The passive entry function is a function that locks / unlocks the vehicle Hv in response to a predetermined user action on the vehicle Hv.

[0034] In this way, the in-vehicle system 10 functions as a system that controls the locking state of the vehicle Hv through cooperation between the body ECU 3 and the position determination device 1. The body ECU 3 may be replaced with an integrated ECU, a zone ECU, or a domain ECU. The body ECU 3 and the position determination device 1 may also be integrated. The functional layout within the in-vehicle system 10 may be changed as appropriate.

[0035] The NFC reader 4 is a module for implementing NFC. The NFC reader 4 attempts to establish a communication connection with the portable device 9 by transmitting a polling command periodically or when a specific event occurs. The polling command is a command for checking whether the portable device 9 is located in a position where the NFC reader 4 can communicate. The NFC reader 4 may be provided on the outer door handle on the driver's seat side, a side mirror, a rear window, a pillar, or the like. The operating state of the NFC reader 4 may be controlled by the position determination device 1.

[0036] The display 5 is a display arranged inside the vehicle. The display 5 displays an image in response to an instruction signal input from the position determination device 1. The display 5 may display a remaining power notification image (described later) based on an instruction from the position determination device 1. The display 5 may be a liquid crystal display, an organic EL display, or a head-up display. The display 5 may be configured to be able to display multiple colors.

[0037] <Portable Device 9> The portable device 9 is a dedicated device that functions as a wireless key for the vehicle Hv. The portable device 9 may be a device that is transferred to the owner together with the vehicle Hv when the vehicle Hv is purchased. The portable device 9 may be considered one of the accessories to the vehicle Hv. The portable device 9 may have any shape, such as a flat rectangular parallelepiped shape, a flat ellipsoid shape (a so-called fob type), or a card shape. The portable device 9 may be called a smart key, a key fob, a key card, an access key, or the like. The portable device 9 functions as a key for the vehicle Hv by performing wireless authentication using the position determination device 1 and the SRWC.

[0038] The portable device 9 may be a general-purpose information processing terminal equipped with an SRWC function. The portable device 9 may be a smartphone or a wearable device. The portable device 9 may also be referred to as a portable device, a user device, a key device, or the like. The portable device 9 may not have any buttons (i.e., push switches) that can be pressed by the user.

[0039] 3 , the portable device 9 includes an acceleration sensor 91, a wireless power receiving unit 92, a battery 93, an SRWC module 94, a UWB module 95, an NFC module 96, and an indicator 97. As described at the beginning, the portable device 9 performs SRWC with the position determination device 1 of the vehicle Hv, and also performs UWB communication with the anchor 2. Hereinafter, the term "vehicle Hv" in SRWC may be read as the position determination device 1 or the in-vehicle system 10. Furthermore, the term "vehicle Hv" in UWB communication (ranging communication) may be read as the anchor 2 or the in-vehicle system 10.

[0040] The acceleration sensor 91 is a sensor that detects acceleration acting on the portable device 9. The acceleration sensor 91 may include multiple detection axes. The acceleration sensor 91 may be a three-axis acceleration sensor. The acceleration sensor 91 detects acceleration at a predetermined interval, such as every 100 milliseconds (10 Hz), and outputs data indicating the detection results (hereinafter, acceleration data) to the SRWC module 94 and the controller 943. The acceleration data may include detected acceleration values ​​for each axis. The acceleration detected by the acceleration sensor 91 represents the magnitude of vibration acting on the portable device 9, in other words, the intensity of the user's movement. The term "acceleration" may be replaced with "vibration" or "movement." The acceleration sensor 91 corresponds to a vibration sensor.

[0041] In other embodiments, the acceleration sensor 91 may be a one-axis or two-axis acceleration sensor. The portable device 9 may be equipped with a gyro sensor instead of or in addition to the acceleration sensor 91 as a sensor for detecting vibrations. In the following description, acceleration may be interpreted as the maximum value among the absolute values ​​of acceleration for each detection axis. The acceleration sensor 91 may be configured to output an activation signal to the controller 943 when it detects acceleration equal to or greater than a predetermined activation threshold. The activation signal may be a signal having a predetermined bit pattern, or may be a signal indicating that the detected acceleration value is equal to or greater than a predetermined value (in other words, acceleration data).

[0042] As shown in FIG. 4 , the wireless power receiving unit 92 receives power transmitted from the wireless charger 6 and charges the battery 93. The wireless charger 6 is a charging device independent of the portable device 9. The wireless charger 6 corresponds to a wireless charging device. The wireless charger 6 includes a power transmitting coil 61, a drive circuit 62, a power supply circuit 63, and the like. The power transmitting coil 61 is a coil for providing power to the portable device 9 by electromagnetically coupling with a power receiving coil 921 provided in the portable device 9. The power transmitting coil 61 is also referred to as a primary coil, and the power receiving coil 921 is also referred to as a secondary coil. The drive circuit 62 is a circuit that generates an alternating current of a predetermined frequency based on power supplied from the power supply circuit 63 and passes the generated current to the power transmitting coil 61. The power supply circuit 63 is a circuit that adjusts the voltage supplied from the external power source 64 to a voltage suitable for operation of the drive circuit 62. The external power source 64 may be a power outlet at home, a mobile battery, an in-vehicle battery, or the like.

[0043] The frequency of the electromagnetic waves used for wireless charging (hereinafter referred to as the charging frequency) may be any frequency. The charging frequency may be a frequency in the 110 kHz to 205 kHz band adopted by the Qi standard. The portable device 9 of this embodiment is compatible with the Qi standard. Of course, the portable device 9 may also be configured to be capable of wireless charging using the AirFuel Inductive / Resonant method.

[0044] The wireless power receiving unit 92 includes a receiving coil 921, a rectifier circuit 922, and a charging control unit 923. The receiving coil 921 is a coil for receiving power wirelessly transmitted from the wireless charger 6 by electromagnetically coupling with the transmitting coil 61. The rectifier circuit 922 is a circuit for converting the power received by the receiving coil 921 into DC power (e.g., DC current). The output voltage of the rectifier circuit 922 is input to the charging control unit 923 and the controller 943. The charging control unit 923 charges the battery 93 with the power input from the rectifier circuit 922.

[0045] The battery 93 stores power for operation of the portable device 9. The battery 93 is a rechargeable battery (i.e., a secondary battery). The battery 93 may be a lithium-ion secondary battery. Of course, the battery 93 may also be a lithium-ion polymer secondary battery, a nickel-cadmium battery, a nickel-metal hydride rechargeable battery, or the like. The battery 93 has a discharge end voltage set. The discharge end voltage is the lowest discharge voltage at which safe discharge can be performed. A state in which the voltage is below the discharge end voltage corresponds to over-discharge. The controller 943, which will be described later, monitors the output voltage of the battery 93 and controls the operation of the portable device 9 so as to prevent over-discharge.

[0046] The SRWC module 94 is a short-range communication module included in the portable device 9. The SRWC module 94 corresponds to a wireless communication unit and a first communication unit. The SRWC module 94 corresponds to the wireless communication unit. The SRWC module 94 includes an antenna 941, an RF (Radio Frequency) core 942, and a controller 943. The SRWC module 94 also includes a clock oscillator that generates a clock for operating the controller 943. The controller 943 corresponds to a control unit.

[0047] The antenna 941 is an antenna element for transmitting and receiving radio waves in the frequency band used for the SRWC (here, the 2.4 GHz band). The RF core 942 is a circuit module that performs processing related to the transmission and reception of radio signals. The RF core 942 may include a modulation circuit, a demodulation circuit, a frequency conversion circuit, an amplifier circuit, a local oscillator, and the like. The RF core 942 is connected to the antenna 941 and a controller 943. The RF core 942 demodulates a signal received by the antenna 21 and provides the demodulated signal to the controller 943. The RF core 942 also modulates transmission data input from the controller 943 and radiates the data as radio waves from the antenna 21. The RF core 942 may be realized as an IC chip (i.e., a transmission / reception IC).

[0048] The controller 943 is a microcomputer that controls the operation of the SRWC module 94 and the entire portable device 9. The controller 943 includes a processor E1, a memory E2, a storage E3, and a communication interface E4. The processor E1 may be a CPU. The memory E2 is a volatile storage medium such as RAM. The storage E3 is a recording device including a non-volatile storage medium such as flash memory. The storage E3 may include multiple types of storage media such as ROM (Read Only Memory) and flash memory. The communication interface E4 is a circuit module that allows the processor E1 to communicate with other components such as the UWB module 95 and NFC module 96.

[0049] The storage E3 stores a device control program. The device control program is a program that includes instructions related to controlling the operation mode. The device control program may be understood as a program corresponding to a mode control method.

[0050] Storage E3 also stores communication data. The communication data is data for wireless communication with the vehicle Hv. The communication data may include parameters received from the position determination device 1 through pairing, such as the device ID of the position determination device 1. The communication data may also include an identification number of the vehicle Hv (hereinafter referred to as vehicle ID). The vehicle ID corresponds to identification information of the vehicle / on-board system to be communicated with. The vehicle ID may be referred to as a system ID. The vehicle ID may be a VIN (Vehicle Identification Number). The communication data may also include a key code used for wireless authentication with the vehicle Hv.

[0051] The SRWC module 94 is configured to be able to perform advertising. Advertising is a process of transmitting an advertising signal using a predetermined channel. The advertising signal is a wireless signal for notifying other devices of its own presence. One advertising may be a process of transmitting an advertising signal once on each of three channels: 37Ch (2402 MHz), 38Ch (2426 MHz), and 39Ch (2480 MHz) out of the 40 channels (0Ch to 39Ch) available in Bluetooth LE. Advertising may also be referred to as advertising or advertisement. Furthermore, when the SRWC module 94 receives a connection request from the vehicle Hv in response to the advertising, it establishes a communication connection with the vehicle Hv. The SRWC module 94 may be interpreted as a module that enables the portable device 9 to perform data communication with the vehicle Hv. The controller 943 can perform authentication processing (i.e., wireless authentication) by the SRWC based on the establishment of a communication connection with the vehicle Hv. Details of the SRWC module 94 and the controller 943 will be described separately later.

[0052] The UWB module 95 is a communication module for performing UWB communication. The UWB module 95 corresponds to a second communication unit. The UWB module 95 outputs received data to the controller 943. The UWB module 95 also transmits a UWB signal corresponding to transmission data input from the controller 943. The UWB module 95 is configured to start up, perform ranging communication, and stop operation based on instructions from the controller 943.

[0053] The ranging communication is communication for measuring the propagation time (in other words, the time of flight) of radio waves from the anchor 2 to the portable device 9. The ranging communication may include a step in which the portable device 9 broadcasts a poll signal and a step in which the anchor 2 transmits a response signal in response to receiving the poll signal. The ranging communication may also include a step in which the portable device 9 transmits a final signal in response to receiving the response signal. The poll signal is a signal that requests the responder to return a response. The response signal may be referred to as an answer signal.

[0054] In ranging communication, the portable device 9 measures the round trip time (hereinafter referred to as RTT), which is the time elapsed from when the portable device 9 transmits a poll signal to the vehicle Hv until when it receives a response signal from the vehicle Hv. RTT is an abbreviation for Round Trip Time. The portable device 9 may calculate a ranging value from the RTT measured by performing ranging communication and transmit the calculated value to the position determination device 1 using SRWC. On the other hand, the anchor 2 may calculate a ranging value based on the time elapsed from when it transmits a response signal to when it receives a final signal from the portable device 9 and report the calculated value to the position determination device 1.

[0055] In the ranging communication of this embodiment, the portable device 9 operates as an initiator, and the vehicle Hv (actually, each anchor 2) operates as a responder. An initiator is a device that plays a leading role in ranging communication. The division of roles in ranging communication may be changed as appropriate. Multiple anchors 2 may individually act as initiators and perform ranging communication with the portable device 9. The ranging communication may include a step in which, prior to transmitting a poll signal, the initiator transmits a pre-poll signal, which is a UWB signal for notifying that ranging will begin. The ranging communication may include a step in which, after transmitting a final signal, the initiator transmits a final data signal, which is a UWB signal indicating that ranging has been successfully performed.

[0056] The NFC module 96 is a module for performing NFC communication. The NFC module 96 is configured as a passive device that returns a signal corresponding to the content of data received from the NFC reader 4. The NFC module 96 is powered by the reception power of the signal transmitted from the NFC reader 4, and generates and returns a response signal. As a more preferred example, the controller 943 of this embodiment is configured to be capable of performing an NFC authentication process, which is user authentication using NFC. The NFC authentication process corresponds to a backup (i.e., an alternative authentication means) in the event that SRWC is not possible. Even during a power-saving mode, which will be described later, the controller 943 may be configured to be activated when the NFC module 96 receives a signal from the vehicle Hv. The NFC module 96 is an optional element and may be omitted.

[0057] The indicator 97 is a light-emitting element for indicating the remaining power of the battery 93. The remaining power is also referred to as SOC (State Of Charge). The remaining power (or SOC) is the ratio of the actual remaining capacity to the fully charged capacity. The indicator 97 is configured to be able to light up in multiple colors, for example, red, yellow, and green. The indicator 97 lights up based on instructions from the controller 943. The controller 943 may light up the indicator 97 in a manner corresponding to the remaining power for a certain period of time (for example, 5 seconds) upon receiving a connection between the portable device 9 and the vehicle Hv via SRWC. The controller 943 may flash the indicator 97 in red if the remaining power is less than 30%. Note that the indicator 97 is an optional element and may be omitted.

[0058] <Operation Modes of Portable Device> The portable device 9 has two operation modes: a normal mode and a power-saving mode. In the normal mode, the controller 943 is activated based on the output of an activation signal from the acceleration sensor 91, and attempts to establish a wireless connection with the vehicle Hv. The normal mode may be understood as an operation mode that is applied in everyday use cases.

[0059] On the other hand, the power saving mode is a mode in which the controller 943 does not activate even when vibrations corresponding to accelerations equal to or greater than the activation threshold act on the portable device 9. Such a power saving mode can be understood as a mode in which advertising does not start even when vibrations act on the portable device 9. In the power saving mode, even when vibrations act on the portable device 9, the SRWC module 94 and the UWB module 95 remain stopped. The power saving mode may be realized by stopping the acceleration sensor 91. In another embodiment, the power saving mode may be a state in which the acceleration sensor 91 is operating but its output signal is disabled by the controller 943. The power saving mode may also be a mode in which the controller 943 does not start advertising even when the acceleration sensor 91 inputs an activation signal to the controller 943.

[0060] While the portable device 9 is set to the normal mode, the portable device 9 transitions among four states: a first advertising state, a second advertising state, a connected state, and a sleep state. The state transitions may be triggered by the detection of vibration, connection / disconnection of communication with the vehicle Hv, etc.

[0061] The first advertising state is a state in which the SRWC module 94 performs advertising at a predetermined first interval. The first interval is set to 30 milliseconds, 50 milliseconds, or 60 milliseconds. The first interval may be set to a value ranging from several tens of milliseconds to several hundreds of milliseconds. The first advertising state is a state in which advertising is performed relatively frequently. In the present disclosure, performing advertising at the first interval is also referred to as fast advertising.

[0062] The second advertising state is a state in which advertising is performed periodically in a manner that consumes less power per unit time than the first advertising state. The second advertising state may be a state in which advertising is performed at a second interval that is longer than the first interval. The second interval may be set to 400 milliseconds, 600 milliseconds, 1 second, 2 seconds, or 3 seconds. The longer the advertising interval, the more power consumption during standby can be reduced. In the present disclosure, performing advertising at the second interval is also referred to as slow advertising.

[0063] In the first advertising state, advertising is frequently performed, and therefore power consumption is high, but the vehicle Hv has the characteristic of being able to easily find the portable device 9 (in other words, the user). On the other hand, in the second advertising state, power consumption is reduced, but the vehicle Hv has a hard time finding the portable device 9 (in other words, the user).

[0064] In this disclosure, the first advertising state and the second advertising state are also collectively referred to as a vehicle searching state. The vehicle searching state corresponds to the periodic transmission mode. The vehicle searching state may be understood as a state in which the SRWC module 94 is active and searching for a vehicle Hv. While the portable device 9 is in the first advertising state or the second advertising state, the controller 943 may set the UWB module 95 to a sleep state. The sleep state of the UWB module 95 may be a state in which some or all of the functions of the UWB module 95 are stopped to reduce power consumption.

[0065] The connected state is a state in which the portable device 9 and the vehicle Hv are connected for communication via SRWC. The portable device 9 transitions to the connected state when it receives a response (e.g., a connection request) from the vehicle Hv in response to the advertisement. While in the connected state, the portable device 9 periodically performs data communication with the vehicle Hv. The controller 943 may transition the UWB module 95 to a state in which it can transmit and receive UWB signals based on the SRWC module 94 being connected to the vehicle Hv via SRWC. While in the connected state, the UWB module 95 performs ranging communication at predetermined intervals, provided that the remaining power is equal to or greater than a predetermined value. The connected state may include a ranging state in which the UWB module 95 periodically performs ranging communication and a non-ranging state in which it does not perform periodic ranging communication.

[0066] The sleep state is a state in which the SRWC module 94 does not transmit an SRWC signal. In the sleep state, the acceleration sensor 91 may continue to operate, while the SRWC module 94 and the UWB module 95 may be stopped. Even in the sleep state, the wireless power receiving unit 92 and the NFC module 96 may be driven by power received from an external source. The charging control unit 923 may be configured to be activated and charge the battery 93 when a voltage equal to or greater than a predetermined value is input from the rectifier circuit 922, even during the sleep state. In the sleep state, the portable device 9 cannot communicate with the vehicle hybrid vehicle, but power consumption can be reduced to the minimum.

[0067] The portable device 9 of this embodiment is configured to transition to a first advertising state upon detection of acceleration equal to or greater than a predetermined wake-up threshold in the sleep state. The controller 943 is configured to wake up and start fast advertising based on input of a wake-up signal from the acceleration sensor 91. In the present disclosure, the transition of the portable device 9 from the sleep state to the first advertising state is also referred to as waking up (activation). The activation of the portable device 9 corresponds to the activation of the controller 943. The activation of the portable device 9 may be understood as the start of clock supply to the processor E1 included in the controller 943. Conversely, the sleep state may be understood as a state in which clock supply to the processor E1 is stopped.

[0068] The portable device 9 automatically transitions to the second advertising state when the elapsed time since transitioning to the first advertising state is equal to or exceeds a predetermined switching time. That is, after waking up, if the portable device 9 does not receive a connection request from the vehicle Hv even after the switching time has elapsed, the portable device 9 automatically transitions to the second advertising state. This changes the advertising interval from the first interval to the second interval, thereby reducing power consumption. The switching time may be set to 20 seconds, 30 seconds, 60 seconds, or the like.

[0069] After startup, the portable device 9 transitions to the sleep state if a state in which acceleration equal to or greater than the sleep threshold is not detected continues for a stop time. The sleep threshold may be the same as the start threshold or may be smaller than the start threshold. The sleep threshold may be a value equivalent to 50% or 25% of the start threshold. Hereinafter, a state in which the acceleration sensor 91 does not detect acceleration equal to or greater than the sleep threshold will also be referred to as a stationary state. The stop time may be set to 60 seconds, 90 seconds, 120 seconds, 180 seconds, etc. In this embodiment, the stop time is set to be longer than the switching time. In other aspects, the stop time may be the same as the switching time or may be shorter than the switching time. The switching time may be referred to as a first switching time, and the stop time may be referred to as a second switching time. Furthermore, the portable device 9 transitions from the connected state to the sleep state if, after becoming connected, a state in which an SRWC signal from the vehicle hybrid continues for a predetermined time, or if a disconnection request signal requesting disconnection is received from the vehicle hybrid.

[0070] The portable device 9 is configured to transition from the normal mode to the power-saving mode when the remaining power of the battery 93 falls below a predetermined stop power. Specifically, the controller 943 acquires the output voltage of the battery 93 upon startup. If the output voltage is equal to or lower than the predetermined stop voltage, the portable device 9 is set to the power-saving mode and the operation of the controller 943 itself is stopped. The process for transitioning to the power-saving mode may include stopping the acceleration sensor 91.

[0071] Furthermore, the process for transitioning to the power-saving mode may be to write a code indicating the power-saving mode to a non-volatile memory (hereinafter, "setting memory") that stores the operation settings (or activation conditions) of the controller 943. The setting memory may be realized using a storage area of ​​the storage E3, or may be a semiconductor memory provided on a circuit board separate from the storage E3. The portable device 9 may be configured so that when the mode setting value of the portable device 9 in the setting memory is 0, the portable device 9 operates in the normal mode, and when the mode setting value is 1, the portable device 9 operates in the power-saving mode. While the mode setting value is 1, the portable device 9 maintains the sleep state regardless of the output of the acceleration sensor 91.

[0072] The stop voltage is designed based on the discharge characteristics of the battery 93. The stop voltage may be 3.4 V, 3.6 V, 3.8 V, etc. The stop voltage may be set to a value greater than the discharge end voltage. If the stop power is set to 20%, the stop voltage may be set to a value corresponding to an SOC of 20%. The stop voltage may be interpreted as a parameter that expresses the remaining power for transitioning to a power saving mode as a voltage value. Of course, the stop voltage may also be a voltage value corresponding to an SOC of 10% or 25%. The stop voltage may be set to a value corresponding to a state in which the SOC is between 5% and 30%.

[0073] Since the output voltage of the battery 93 corresponds to the remaining power of the battery 93, acquiring the output voltage corresponds to acquiring the remaining power. In the following, the expression "when the output voltage is equal to or lower than the stop voltage" may be interpreted as "when the remaining power is less than the stop power." In other words, the remaining power and the output voltage may be interpreted interchangeably. The stop power is a power value corresponding to the stop voltage. The stop power is set to a value between 5% and 30%, such as 10%, 20%, or 25%. The stop voltage and the stop power correspond to the stop threshold. The stop voltage described above may be interpreted as a parameter that expresses the stop threshold in terms of voltage, and the stop power as a parameter that expresses the stop threshold in terms of the remaining power (percentage).

[0074] The timing at which the controller 943 acquires the output voltage may be changed as appropriate. The controller 943 may acquire the output voltage of the battery 93 when the vehicle Hv is connected via the SRWC. The controller 943 may also acquire the output voltage periodically (e.g., every five minutes) while the controller 943 is running. Furthermore, the controller 943 may acquire the output voltage upon receiving a request to start ranging communication from the vehicle Hv. The controller 943 may perform processing to set the portable device 9 to a power-saving mode whenever it detects that the output voltage is equal to or lower than the stop voltage.

[0075] Furthermore, the portable device 9 may be configured to cancel the power-saving mode and return to the normal mode upon the start of wireless charging, as shown in FIG. 5 . Specifically, the controller 943 may be configured to be activated upon receiving a high-level voltage signal from the rectifier circuit 922 (S01) and to execute a process for returning to the normal mode (S02). The high-level voltage signal output by the rectifier circuit 922 is also referred to as a charging signal in this disclosure. The process for returning to the normal mode may include enabling the acceleration sensor 91. The process for returning to the normal mode may also include rewriting a mode setting value in the setting memory from a value corresponding to the power-saving mode (e.g., 1) to a value corresponding to the normal mode (0).

[0076] A high-level voltage signal may be understood as a voltage signal having a magnitude equal to or greater than a predetermined value. In the power-saving mode, the controller 943 may be configured to start up in response to the input voltage from the rectifier circuit 922 rising from a low level to a high level. The output terminal of the rectifier circuit 922 may be connected to a reset terminal (e.g., an MCLR terminal) of the controller 943 via a circuit that inverts the high level / low level.

[0077] The controller 943 may be configured to execute processing to set the portable device 9 to the power-saving mode when the remaining power falls below a predetermined value or when the output signal of the rectifier circuit 922 fluctuates in a predetermined pattern. The controller 943 may be configured to set the portable device 9 to the power-saving mode when the output signal of the rectifier circuit 922 rises or falls a predetermined number of times within a certain period of time. As shown in FIG. 6 , the controller 943 may be configured to set the portable device 9 to the power-saving mode when the output signal of the rectifier circuit 922 rises three times within 10 seconds. With this configuration, a user / administrator can force the portable device 9 to the power-saving mode by repeatedly placing the portable device 9 on the wireless charger 6 a predetermined number of times. The administrator may force the portable device 9 to the power-saving mode by performing the above operation while transporting the portable device 9 from a manufacturing factory to a sales outlet. This further reduces the remaining power consumption during transportation. The administrator here may be interpreted as a person who manufactures or sells the portable device 9.

[0078] <Communication Flow> Figure 7 is a diagram showing an outline of the communication flow between the portable device 9 and the vehicle Hv. At the start of the sequence shown in Figure 7, the portable device 9 is sufficiently far away from the vehicle Hv and is not connected to the vehicle Hv for communication. The portable device 9 is in the normal mode.

[0079] When the portable device 9, which is a peripheral, is in normal mode, it periodically transmits an advertising signal in response to the detection of vibration by the acceleration sensor 91 (S11). The portable device 9 enters a reception standby state for a short time immediately after transmitting the advertising signal. As the user moves, the portable device 9 enters the SRWC area of ​​the vehicle Hv, and the vehicle Hv can receive the advertising signal from the portable device 9. Upon receiving the advertising signal from the portable device 9, the vehicle Hv transmits a connection request signal to the portable device 9 (S12). This causes the portable device 9 and the vehicle Hv to transition to a communication connection state. The communication connection state may be interpreted as a state in which an SRWC link is established. The connection request signal is a signal that requests a communication connection. In the present disclosure, the connection request signal may also be abbreviated as a connection request. In the communication connection state, the vehicle Hv and the portable device 9 transmit and receive wireless signals to confirm communication at predetermined intervals, and perform encrypted data communication.

[0080] When the controller 943 establishes a communication connection with the vehicle Hv via the SRWC, it transmits data indicating the remaining power to the vehicle Hv via the SRWC (S13). Furthermore, when the SRWC module 94 completes communication connection with the vehicle Hv, the controller 943 exchanges parameters for ranging communication (hereinafter, ranging settings) with the vehicle Hv via the SRWC as a preparation process for ranging communication. The ranging setting data is a data set including ranging parameters, which are parameters for ranging communication. The ranging setting data includes, for example, the interval at which ranging communication is performed.

[0081] The exchange of ranging settings may include a step (S14) in which the position determination device 1 transmits data indicating desired ranging settings, and a step (S15) in which the portable device 9 accepts the ranging settings proposed by the position determination device 1. Note that in this embodiment, the position determination device 1 determines the values ​​of various ranging parameters, but this is not limited to this. Some or all of the ranging parameters may be determined or proposed by the portable device 9. Step S15 may also be a step in which the portable device 9 transmits or proposes ranging settings to the position determination device 1.

[0082] Once the ranging settings have been exchanged, in other words, the ranging settings have been agreed upon, the portable device 9 periodically performs ranging communication (S16) with the vehicle Hv. One ranging communication includes the portable device 9 and each anchor 2 transmitting and receiving a ranging UWB signal. The ranging UWB signal includes the pre-poll signal, poll signal, response signal, final signal, and final data signal described above. The controller 943 causes the UWB module 95 to perform ranging communication with each of the multiple anchors 2 in a manner consistent with the ranging settings.

[0083] The controller 943 also performs data communication with the vehicle Hv at a predetermined connection interval to check connectivity (S17). The data communication for checking connectivity is performed using the SRWC. The connection interval is the interval at which data communication is performed. The connection interval may be determined at the time of communication connection or pairing.

[0084] After the start of ranging communication, the portable device 9 and the vehicle Hv repeat steps S16 and S17 until a predetermined termination condition is met. When the termination condition is met, the portable device 9 terminates the repeated ranging communication with the vehicle Hv and enters a sleep state. The termination condition may be the disconnection of the communication connection between the position determination device 1 and the portable device 9. The controller 943 may release (i.e., disconnect) the connection with the vehicle Hv if a state in which an SRWC signal is not received from the vehicle Hv continues for a predetermined time (e.g., Super Vision Time). The controller 943 may also determine that the termination condition is met if an SRWC termination request signal is received from the vehicle Hv. The controller 943 may also determine that the termination condition is met if the duration of the stationary state reaches the stop time. Alternatively, the controller 943 may determine that the termination condition is met if the remaining power becomes equal to or less than the stop voltage. When the remaining power becomes equal to or less than the stop voltage, the controller 943 ends the distance measurement communication and then performs processing to transition to the power saving mode.

[0085] <Example of Operation of Portable Device> Here, operation of the portable device 9 related to mode switching will be described using the flowchart shown in FIG. 8. The series of processes shown in FIG. 8 can be called a mode control process. The mode control process may include steps S101 to S111 as shown in FIG. 8. The description of the controller 943 as the entity executing the following processes may be replaced with the processor E1, the SRWC module 94, or the portable device 9.

[0086] 8 may be started when an activation signal is input from the acceleration sensor 91 to the controller 943, in other words, when the acceleration sensor 91 detects acceleration equal to or greater than the activation threshold. As the preparatory process of step S101, the mode control process may include a step in which the controller 943 determines whether acceleration equal to or greater than the activation threshold is detected based on the output signal of the acceleration sensor 91. This preparatory process may be executed periodically during the sleep state.

[0087] Step S101 is a step in which the controller 943 executes a startup process. The startup process is a process of transitioning from a sleep state to a state in which an advertisement can be transmitted. The startup process may include starting a clock supply to the processor E1 and the processor E1 reading out a program and / or communication data stored in the storage E3 and storing it in the RAM 872. The startup process may also include starting power supply to the RF core 942. When step S101 is completed, the process proceeds to step S102.

[0088] Step S102 is a step in which the controller 943 acquires the output voltage of the battery 93. Vo in the drawing represents the output voltage of the battery 93. When step S102 is completed, the process proceeds to step S103.

[0089] In step S103, the controller 943 determines whether the output voltage of the battery 93 is greater than the stop voltage. Vstp in the figure represents the stop voltage. If the output voltage is greater than the stop voltage (YES in S103), the process proceeds to step S105. On the other hand, if the output voltage is equal to or less than the stop voltage (NO in S103), the process proceeds to step S104.

[0090] In step S104, the controller 943 executes a process for setting the portable device 9 to the power-saving mode. As described above, the process for setting the portable device 9 to the power-saving mode may be to stop the acceleration sensor 91 or to rewrite the mode setting value in the setting memory. When step S104 is completed, this flow ends.

[0091] Step S105 is a step in which the controller 943 starts advertising in the first advertising state. As a result, the SRWC module 94 starts periodically transmitting an advertising signal at the first interval. Note that, if the duration of the first advertising state is equal to or longer than the switching time, the controller 943 switches the operation mode of the portable device 9 from the first advertising state to the second advertising state. In other words, the advertising interval is changed from the first interval to the second interval. After step S105, the controller 943 performs advertising at the first interval or the second interval until a sleep condition is satisfied or communication connection with the vehicle Hv is established. The sleep condition is a condition under which the portable device 9 transitions to the sleep state. The sleep condition may be that the acceleration sensor 91 of the portable device 9 does not detect acceleration equal to or greater than the sleep threshold for a continuous stopped time.

[0092] The controller 943 executes the determination process of step S106 each time advertising is executed. Step S106 is a step for determining whether or not a communication connection has been established with the vehicle Hv via the SRWC. If a communication connection has been established with the vehicle Hv, the process proceeds to step S108. On the other hand, if a communication connection has not been established with the vehicle Hv, the process proceeds to step S107. If a communication connection has not been established with the vehicle Hv, this refers to the case where a connection request has not been received from the vehicle Hv in response to the advertising.

[0093] Step S107 is a step for determining whether the sleep condition is satisfied. If the sleep condition is not satisfied, that is, if the duration of the stationary state has not reached the stop time, the controller 943 performs advertising after a predetermined time and performs the connection determination of step S106. In the present disclosure, the advertising and the accompanying steps S106 to S107 are collectively referred to as a vehicle search process. The vehicle search process may be repeatedly executed until communication is established with the vehicle Hv or until the sleep condition is satisfied.

[0094] In step S107, if the sleep condition is satisfied, that is, if the duration of the stationary state reaches the stop time, the controller 943 performs processing to transition to the sleep state (S111). The processing to transition to the sleep state may be processing to stop the operation of the SRWC module 94. The processing to transition to the sleep state may be processing to stop the clock oscillator.

[0095] Step S108 is a step in which the controller 943 exchanges distance measurement settings with the vehicle Hv via the SRWC. Step S108 corresponds to steps S14 and S15 described above. Once the exchange of distance measurement settings is complete, the process proceeds to step S109. Step S109 is a step in which periodic distance measurement communication is started. Periodic distance measurement communication may be understood as periodically (repeatedly) executing distance measurement communication according to the exchanged distance measurement settings. Steps S109 and subsequent steps are steps in which it is determined whether or not a termination condition is met. If the termination condition is met, the portable device 9 transitions to a sleep state (S111). Until the termination condition is met, the controller 943 repeatedly executes distance measurement communication (S16) and data communication for communication confirmation (S17), as described in FIG. 7 .

[0096] The above control may be performed using the remaining power (i.e., SOC) instead of the output voltage. Step S103 may be a step of determining whether the remaining power exceeds the stop power. Additionally, the controller 943 may periodically measure the output voltage of the battery 93 while in operation. If the controller 943 detects that the measured output voltage is equal to or lower than the stop voltage, the controller 943 may execute processing (S104) to promptly transition to the power saving mode. Furthermore, the controller 943 may transmit data indicating the remaining power to the vehicle Hv via the SRWC each time it measures the output voltage.

[0097] <Effects> The portable device 9 automatically switches its operating mode from normal mode to power-saving mode when the remaining power of the battery 93 falls below a predetermined value. The power-saving mode is a mode in which the portable device 9 does not start even when vibration occurs in the portable device 9. The above process reduces the risk of the battery 93 reaching an over-discharge state. Furthermore, the life of the battery 93 can be extended.

[0098] Furthermore, the portable device 9 returns from the power-saving mode to the normal mode when charging using the wireless charger 6 is initiated. Therefore, the user does not need to operate any buttons on the portable device 9 to return the portable device 9 to the normal mode. Even if the portable device 9 unintentionally enters the power-saving mode due to power consumption during transportation, for example, the administrator can return the portable device 9 to the normal mode.

[0099] Furthermore, the portable device 9 transitions to power-saving mode even when the remaining power is equal to or greater than a predetermined value based on the wireless charging state, specifically, whether the output signal of the rectifier circuit 922 fluctuates in a predetermined pattern. Therefore, if the portable device 9 will not be used for a long period of time, such as during transportation, an administrator can intentionally set the portable device 9 to power-saving mode. Furthermore, no button is used when setting the portable device 9 to power-saving mode. Therefore, the portable device 9 does not need to have a button. Because the portable device 9 of this embodiment does not need to have a button, it can be made smaller than a portable device that has a button.

[0100] <Modification> The portable device 9 may be configured to cancel the power-saving mode not only when wireless charging has started but also when the remaining power reaches or exceeds a predetermined return power. The return power may be set to a value greater than the stop power by a predetermined amount. The predetermined amount may be, for example, 5 percentage points (hereinafter, pp). The controller 943 may periodically measure the remaining power while wireless charging has started. Then, when the controller 943 detects that the remaining power is greater than or equal to the return power through wireless charging, it may perform processing to return to the normal mode. The return power and stop power in the above description may be rephrased as the return voltage and stop voltage, respectively.

[0101] When the position determination device 1 is connected to the portable device 9 via SRWC, the position determination device 1 may acquire data indicating the remaining power from the portable device 9 via SRWC. In this case, the position determination device 1 may display a remaining power notification image on the display 5. In other words, when the portable device 9 is connected to the vehicle Hv via SRWC, the portable device 9 may transmit data indicating the remaining power to the vehicle Hv via SRWC, and the remaining power notification image may be displayed on the display 5. The remaining power notification image is an image indicating the remaining power of the battery 93. The data indicating the remaining power may be the SOC value or the output voltage value of the battery 93. This configuration makes it easy for the user to recognize the remaining power of the portable device 9. Note that the appearance of the remaining power notification image may be changed depending on the remaining power. The position determination device 1 may change the display from "High," "Mid," "Low," to "Critical" in this order as the remaining power decreases. The position determination device 1 may flash the remaining power notification image when the remaining power falls below the emergency value. The emergency value may be a value obtained by adding a predetermined value (for example, 10 pp) to the outage power. For example, if the outage power is 20%, the emergency value may be set to 30%.

[0102] Furthermore, the position determination device 1 may change the interval at which UWB ranging communication is performed depending on the remaining power of the battery 93. As shown in Fig. 9, if the remaining power is greater than a predetermined first power (YES in S201), the position determination device 1 sets the ranging interval to the first ranging interval (S202). If the output power is equal to or less than the first power and greater than the second power (YES in S203), the position determination device 1 sets the ranging interval to the second ranging interval (S204). If the output power is equal to or less than the second power (NO in S203), the position determination device 1 may prohibit ranging communication (S205).

[0103] 9, "RP" represents the remaining power, "P1" represents the first power, and "P2" represents the second power. Also, "RI" represents the actually applied ranging interval, "Tr1" represents the first ranging interval, and "Tr2" represents the second ranging interval. The first power and the second power are thresholds for the remaining power.

[0104] The first power may be set to a value corresponding to a state in which there is sufficient remaining power. The first power may be set to 40% or 50%. The second power is a threshold for protecting the battery by stopping ranging communication. The second power may be set to the same value as the stop power. The second power may also be 5 pp or 10 pp higher than the stop power. The remaining power value at which advertising stops and the remaining power value at which UWB ranging stops may be different.

[0105] The first ranging interval may be 100 milliseconds, 150 milliseconds, 200 milliseconds, etc. The second ranging interval may be set to a value relatively larger than the first ranging interval, such as 500 milliseconds, 1 second, or 2 seconds.

[0106] By lengthening the ranging interval as the remaining power decreases, the power consumption of the portable device 9 can be reduced. By setting the ranging interval to a relatively short value when there is sufficient remaining power, the system responsiveness to the user's approach to the vehicle Hv and user convenience can be improved. Furthermore, by stopping ranging communication when the remaining power is extremely low, the risk of the battery 93 reaching an over-discharge state can be reduced. Furthermore, although the above description has been given of the case where the position determination device 1 determines the ranging interval, the portable device 9 may also adjust the ranging interval according to the remaining power.

[0107] Furthermore, the portable device 9 may change the rules for executing advertising depending on the remaining power, as shown in Fig. 10. That is, if the remaining power is greater than a predetermined normal operating power (Pn) (YES in S301), the controller 943 executes advertising in a manner that complies with a predetermined first rule (S302). In the figure, "Pn" represents the normal operating power. The normal operating power is a threshold value for the remaining power.

[0108] The first rule may be, for example, to perform advertising at a first interval until a predetermined first switching time has elapsed, and then to perform advertising at a second interval. In other words, the first rule may be to operate in a first advertising state for a first switching time after startup, and then operate in a second advertising state. Of course, the portable device 9 transitions to a sleep state if a sleep condition is satisfied over time. Furthermore, the portable device 9 may transition to a connected state when a connection request is received from the vehicle Hv. The first switching time is a parameter corresponding to the aforementioned switching time. The first switching time corresponds to the first period.

[0109] The normal operating power may be set to 25%, 30%, 35%, etc. The normal operating power is set to a value that is a predetermined amount (5 or 10 pp) less than the first power. In a configuration where the first power is set to 35%, the normal operating power may be set to 30% or 25%. In other embodiments, the normal operating power may be the same as the first power.

[0110] Furthermore, if the output power is equal to or less than the normal operating power and greater than the stop power (YES in S303), the position determination device 1 executes advertising in a manner that complies with a predetermined second rule (S304). "Pstp" in the figure represents the stop power.

[0111] The second rule is set to reduce power consumption more than the first rule. For example, the second rule may require the device to operate in the first advertising state for a second switching time after startup, and then switch to the second advertising state. The second switching time may be set shorter than the first switching time. For example, if the first switching time is 30 seconds, the second switching time may be set to 15 seconds. The second rule may require the device to maintain the first advertising state for a shorter period of time than the first rule. The second switching time corresponds to the second period. When the second rule is applied, the controller 943 may perform fast advertising until the second switching time has elapsed, and then perform slow advertising. If the output power of the portable device 9 is equal to or less than the stop power (NO in S303), the portable device 9 transitions from the normal mode to the power saving mode (S305).

[0112] The second rule may be to immediately perform slow advertising after startup without going through the first advertising state. The second rule may also be to operate in a third advertising state after startup. The third advertising state may be a state in which advertising is periodically performed in a manner that can further reduce power consumption per unit time compared to the second advertising state.

[0113] The third advertising state may be a state in which advertising is performed at a third interval that is even longer than the second interval. The third interval may be 4 seconds, 6 seconds, 10 seconds, etc. Advertising at the third interval is also referred to as very slow advertising in this disclosure.

[0114] According to the above configuration, when there is sufficient remaining power, communication connectivity is improved by advertising frequently. Here, communication connectivity can be interpreted as the ease of communication connection. Furthermore, when there is insufficient remaining power, the frequency of advertising is reduced to prevent the remaining power from decreasing. Furthermore, when the remaining power is extremely low, the battery can be protected by switching to a power-saving mode in which advertising is not performed. Furthermore, according to the above configuration, as the remaining power decreases, the responsiveness of the system to the user's approach to the vehicle Hv decreases. This reduced responsiveness makes it easier for the user to notice the decrease in remaining power.

[0115] The various controls described above may be performed using the output voltage instead of the remaining power (i.e., SOC). Steps S201, S203, S301, and S303 may be steps of comparing the output voltage with a predetermined threshold. Furthermore, the controller 943 may be configured to be able to perform a combination of multiple controls, such as changing the ranging interval according to the remaining power and changing the execution rules for advertisement.

[0116] The second advertising state is not limited to a state in which the advertising interval is extended compared to the first advertising state. The reduction in power consumption may be achieved by reducing the transmission power of the advertising signal. The second advertising state may be a state in which the transmission power of the advertising signal is reduced by a predetermined amount compared to the first advertising state. In this case, the advertising interval may be the same in the first advertising state and the second advertising state. This setting also achieves the same effects as the above embodiment.

[0117] The third advertising state may be a mode in which transmission power is reduced by a predetermined amount compared to the second advertising state. When the second advertising state is a state in which an advertising signal is periodically transmitted at the first transmission power and the second interval, the third advertising state may be a state in which an advertising signal is periodically transmitted at the second transmission power and the second interval. The first transmission power is the transmission power in the first advertising state. The second transmission power may be set to a value smaller than the first transmission power.

[0118] In the present disclosure, the operating mode to which the first rule is applied after the controller 943 is activated is referred to as the standard mode, and the operating mode to which the second rule is applied is also referred to as the limited mode. That is, the portable device 9 may have a standard mode, a limited mode, and a power-saving mode as its operating modes. The standard mode corresponds to the first mode, and the limited mode corresponds to the second mode. The power-saving mode corresponds to the third mode. The standard mode and the limited mode may be interpreted as operating modes obtained by subdividing the normal mode. When the remaining power is greater than the normal operating power, the portable device 9 may operate in the standard mode, and when the remaining power is equal to or less than the normal operating power and equal to or greater than the shutdown power, the portable device 9 may operate in the limited mode. The threshold for returning from the limited mode to the standard mode may be set to a value that is a predetermined amount greater than the threshold for transitioning from the standard mode to the limited mode. In a configuration in which the portable device 9 has the limited mode, the controller 943 may be configured to transition from the power-saving mode to the limited mode when wireless charging is started or when the remaining power becomes equal to or greater than a predetermined return power.

[0119] The controller 943 may estimate the remaining power based on the output voltage of the battery 93. The method for estimating the remaining power (i.e., the SOC) is not limited to the OCV (Open Circuit Voltage) method. The controller 943 may estimate the remaining power using a current integration method (Coulomb counting method) or an impedance tracking method. The controller 943 may estimate the remaining power using any estimation method. The controller 943 may set the operation mode of the portable device 9 to a power saving mode when the estimated SOC value falls below a predetermined value.

[0120] Some of the functions of the controller 943 may be provided by an IC / processor provided outside the SRWC module 94. The controller 943 may be provided outside the SRWC module 94. The functional layout within the portable device 9 may be changed as appropriate. In other embodiments, the portable device 9 may be provided with one or more push switches.

[0121] The method of data communication between the portable device 9 and the position determination device 1 is not limited to Bluetooth LE, and may be Bluetooth Classic, Wi-Fi (registered trademark), EnOcean (registered trademark), Zigbee (registered trademark), etc. The wireless protocol used for data communication (communication connection) may be referred to as the first wireless protocol, and the wireless protocol used for ranging communication may be referred to as the second wireless protocol.

[0122] Ranging communication is not limited to UWB-IR, and may be performed using Bluetooth LE, Wi-Fi, or the like. For example, a ranging method using Bluetooth LE may be CS (Channel Sounding) ranging. CS ranging is a method of measuring distance based on the difference in reception phase for each channel, obtained by transmitting and receiving CW (Continuous Wave) signals over multiple channels. CS ranging is sometimes called High Accuracy Distance Measurement (HADM) or phase difference ranging.

[0123] <Supplementary Remark (1)> The present disclosure also includes the following technical ideas and configurations. The present disclosure also includes a mode control method, a computer program, and a recording medium on which the computer program is recorded, which correspond to the following technical ideas.

[0124] [Technical Idea 1] A portable device that functions as a wireless door key and operates on a secondary battery (93), comprising: a wireless communication unit (94) for wirelessly communicating with a system that controls the locking state of the door; and a control unit (943) that controls the wireless communication unit, wherein the control unit is configured to: transmit, using the wireless communication unit, an advertising signal, which is a wireless signal for connecting and communicating with the system; acquire data indicating the remaining power of the secondary battery; and change the operating mode of the portable device related to the transmission of the advertising signal based on the remaining power.

[0125] [Technical Idea 2] The portable device according to Technical Idea 1, further comprising: a wireless power receiving unit (92) that charges the secondary battery using power wirelessly transmitted from an externally provided wireless charging device; and a vibration sensor (91) that detects vibrations, wherein the operation modes include a normal mode in which the wireless communication unit transmits the advertising signal based on the vibration sensor detecting vibrations, and a power saving mode in which the wireless communication unit does not transmit the advertising signal even when the portable device vibrates, and wherein the control unit is configured to set the portable device to the power saving mode when the remaining power becomes less than a stop threshold, and to cancel the power saving mode based on the wireless power receiving unit receiving power from the wireless charging device. Note that the power saving mode may be a mode in which the wireless communication unit does not transmit the advertising signal regardless of the output of the vibration sensor, or a mode in which the vibration sensor is stopped.

[0126] [Technical Idea 3] A portable device according to Technical Idea 2, wherein no push switch is provided, the wireless power receiving unit includes a rectifier circuit (922) that generates a direct current based on the power received from the wireless charging device, and the control unit is configured to set the portable device to the power saving mode based on the output level of the rectifier circuit fluctuating in a predetermined pattern.

[0127] [Technical Concept 4] The portable device according to any one of Technical Concepts 1 to 3, wherein the control unit is configured to change whether or not to transmit the advertising signal based on the remaining power.

[0128] [Technical Idea 5] A portable device described in any one of Technical Ideas 1 to 4, wherein the operating modes include a periodic transmission mode in which the wireless communication unit periodically transmits the advertising signal, and the control unit is configured to change the transmission interval of the advertising signal in the periodic transmission mode based on the remaining power.

[0129] [Technical Idea 6] A portable device according to any one of Technical Ideas 1 to 5, including a vibration sensor that detects vibrations, wherein the operating modes include a first mode in which the wireless communication unit repeatedly transmits the advertising signal according to a predetermined rule in response to the vibration sensor detecting vibrations, a second mode in which the wireless communication unit repeatedly transmits the advertising signal according to a rule that can reduce power consumption more than in the first mode in response to the vibration sensor detecting vibrations, and a third mode in which the wireless communication unit does not transmit the advertising signal even when the portable device vibrates, and the control unit selects the operating mode from the first, second, and third modes according to the remaining power.

[0130] The third mode may be a mode in which the wireless communication unit does not transmit the advertising signal regardless of the output of the vibration sensor, or a mode in which the vibration sensor is stopped. The third mode corresponds to the power saving mode.

[0131] [Technical Idea 7] The portable device described in Technical Idea 6, wherein the first mode is an operating mode in which, upon detection of vibration by the vibration sensor, the wireless communication unit starts repeatedly transmitting the advertising signal at a predetermined first interval, and the second mode is an operating mode in which, upon detection of vibration by the vibration sensor, the wireless communication unit starts repeatedly transmitting the advertising signal at a second interval that is longer than the first interval.

[0132] [Technical Idea 8] The portable device described in Technical Idea 6, wherein the first mode is an operating mode that includes changing the transmission interval of the advertising signal to a second interval that is longer than the first interval after the wireless communication unit has repeatedly transmitted the advertising signal at a predetermined first interval for a predetermined first period after the vibration sensor has detected vibration, and the second mode is an operating mode that includes changing the transmission interval of the advertising signal to the second interval after the wireless communication unit has repeatedly transmitted the advertising signal at the first interval for a second period that is shorter than the first period after the vibration sensor has detected vibration.

[0133] [Technical Concept 9] The portable device according to any one of Technical Concepts 6 to 8, wherein the third mode is an operation mode in which the vibration sensor is stopped.

[0134] [Technical Idea 10] A portable device described in any one of Technical Ideas 1 to 9, wherein the wireless communication unit is a first communication unit that performs data communication with the system using a predetermined first wireless protocol, and further includes a second communication unit (95) that is configured to be able to perform ranging communication, which is communication for measuring distance, with the system using a second wireless protocol different from the first wireless protocol, and the control unit is configured to determine whether or not to cause the second communication unit to perform the ranging communication, or the interval at which to perform the ranging communication, based on the remaining power.

[0135] [Technical Idea 11] The portable device according to Technical Idea 10, wherein the first wireless protocol is Bluetooth (registered trademark) Low Energy, and the second wireless protocol is Ultra Wide Band - Impulse Radio.

[0136] [Technical Idea 12] A portable device described in any one of Technical Ideas 1 to 11, further comprising a vibration sensor that detects vibrations, wherein the control unit is configured to be activated in response to the vibration sensor detecting vibrations, and to determine the remaining power based on the output voltage of the secondary battery.

[0137] [Technical Idea 12A] The portable device described in any one of Technical Ideas 1 to 12, wherein the control unit is configured to transmit data indicating the remaining power to the system using the wireless communication unit based on the establishment of a communication connection with the system.

[0138] [Technical Idea 12B] The portable device described in any one of Technical Ideas 1 to 12, wherein the control unit is configured to transmit a wireless signal to the system using the wireless communication unit to display the remaining power on a display based on communication connection with the system.

[0139] <Supplementary Note (2)> The various flowcharts shown in this disclosure are all examples, and the number of steps constituting the flowcharts and the execution order of the processes can be changed as appropriate. The controls shown in each flowchart may be combined / executed in parallel to the extent that there is no contradiction. Expressions such as acquisition, determination, detection, generation, and calculation may be interchangeable. The acquisition of certain data by a certain device also includes the device generating the data based on a signal input from another device / sensor. The present disclosure is not limited to systems that control the locking / unlocking of vehicles, but can also be applied to systems that control the locking status of building doors. The portable device 9 may be a wireless key for a building door, or a wireless key for a door such as a locker.

[0140] The apparatus, system, and method described herein may be implemented by a special-purpose computer including a processor programmed to execute one or more functions embodied in a computer program. The apparatus and method described herein may be implemented using dedicated hardware logic circuits. The apparatus and method described herein may be implemented by one or more special-purpose computers configured by combining a processor executing a computer program with one or more hardware logic circuits. The processor may be any computing core, such as a CPU, MPU, GPU, or DFP (Data Flow Processor). Some or all of the functions of the controller 943 may be implemented as hardware. Some or all of the functions of the controller 943 may be implemented using a system-on-chip (SoC), an integrated circuit (IC), or a field-programmable gate array (FPGA). The same applies to the functions of the position determination device 1.

[0141] The computer program includes instructions that are executed by a computer. The computer program may be stored in a computer-readable non-transitory tangible storage medium. The storage medium for the computer program may be a variety of media, such as a hard-disk drive (HDD), a solid-state drive (SSD), or a flash memory.

Claims

1. A portable device that functions as a wireless door key and operates on a secondary battery (93), comprising: a wireless communication unit (94) for wirelessly communicating with a system that controls the locking status of the door; and a control unit (943) that controls the wireless communication unit, wherein the control unit is configured to: transmit, using the wireless communication unit, an advertising signal, which is a wireless signal for connecting and communicating with the system; obtain data indicating the remaining power of the secondary battery; and change the operating mode of the portable device related to the transmission of the advertising signal based on the remaining power.

2. A portable device as described in claim 1, further comprising a wireless power receiving unit (92) that charges the secondary battery using power wirelessly transmitted from an external wireless charging device, and a vibration sensor (91) that detects vibration, wherein the operating modes include a normal mode in which the wireless communication unit transmits the advertising signal based on the vibration sensor detecting vibration, and a power saving mode in which the wireless communication unit does not transmit the advertising signal even if the portable device vibrates, and the control unit is configured to set the portable device to the power saving mode when the remaining power falls below a stop threshold, and to cancel the power saving mode based on the wireless power receiving unit receiving power from the wireless charging device.

3. A portable device as described in claim 2, wherein a push switch is not provided, the wireless power receiving unit includes a rectifier circuit (922) that generates a direct current based on the power received from the wireless charging device, and the control unit is configured to set the portable device to the power saving mode based on the output level of the rectifier circuit fluctuating in a predetermined pattern.

4. The portable device according to claim 1, wherein the control unit is configured to change whether or not to transmit the advertising signal based on the remaining power.

5. The portable device of claim 1, wherein the operating modes include a periodic transmission mode in which the wireless communication unit periodically transmits the advertising signal, and the control unit is configured to change the transmission interval of the advertising signal in the periodic transmission mode based on the remaining power.

6. A portable device as described in claim 1, including a vibration sensor that detects vibrations, the operating modes including: a first mode in which, in response to the vibration sensor detecting vibration, the wireless communication unit repeatedly transmits the advertising signal according to a predetermined rule; a second mode in which, in response to the vibration sensor detecting vibration, the wireless communication unit repeatedly transmits the advertising signal according to a rule that can reduce power consumption more than in the first mode; and a third mode in which the wireless communication unit does not transmit the advertising signal even if the portable device vibrates, and the control unit selects the operating mode from the first, second, and third modes according to the remaining power.

7. A portable device as described in claim 6, wherein the first mode is an operating mode in which, upon detection of vibration by the vibration sensor, the wireless communication unit begins to repeatedly transmit the advertising signal at a predetermined first interval, and the second mode is an operating mode in which, upon detection of vibration by the vibration sensor, the wireless communication unit begins to repeatedly transmit the advertising signal at a second interval longer than the first interval.

8. The portable device of claim 6, wherein the first mode is an operating mode including changing the transmission interval of the advertising signal to a second interval longer than the first interval after the wireless communication unit has repeatedly transmitted the advertising signal at a predetermined first interval for a predetermined first period after the vibration sensor detects vibration, and the second mode is an operating mode including changing the transmission interval of the advertising signal to the second interval after the wireless communication unit has repeatedly transmitted the advertising signal at the first interval for a second period shorter than the first period after the vibration sensor detects vibration.

9. The portable device according to any one of claims 6 to 8, wherein the third mode is an operation mode in which the vibration sensor is stopped.

10. The portable device of claim 1, wherein the wireless communication unit is a first communication unit that performs data communication with the system using a predetermined first wireless protocol, and further comprises a second communication unit (95) that is configured to be able to perform ranging communication, which is communication for measuring distance, with the system using a second wireless protocol different from the first wireless protocol, and the control unit is configured to determine whether or not to cause the second communication unit to perform the ranging communication, or the interval at which to perform the ranging communication, based on the remaining power.

11. The portable device of claim 10, wherein the first wireless protocol is Bluetooth (registered trademark) Low Energy, and the second wireless protocol is Ultra Wide Band - Impulse Radio.

12. A portable device as described in claim 1, further comprising a vibration sensor that detects vibrations, wherein the control unit is configured to be activated in response to the vibration sensor detecting vibrations and to determine the remaining power based on the output voltage of the secondary battery.

13. A mode control method executed by a portable device configured to operate on a secondary battery (93) and function as a wireless key for a door, the mode control method including: transmitting, using a wireless communication unit (94), an advertising signal, which is a wireless signal for communicating with a system that controls the locking status of the door; acquiring the remaining power of the secondary battery; and changing the operating mode of the portable device related to the transmission of the advertising signal based on the remaining power.

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