Portable device

Abstract

To provide a technique for suppressing over-discharge of a secondary battery at a lower cost in a portable device that operates using the secondary battery.SOLUTION: A battery 41 and a main controller 10 are connected via a first regulator 42, which is an LDO. An enable terminal 423 of the first regulator 42 is connected to a control terminal 16 provided in the main controller 10. During normal operation, the main controller 10 sets the output level of the control terminal 16 to a high level, thereby maintaining the enable input voltage of the first regulator 42 at a high level. The main controller 10 monitors the battery voltage, and when the battery voltage falls below a predetermined value, it lowers the output level of the control terminal 16 to a low level, thereby stopping the first regulator 42. As a result, the battery 41 and the main controller 10 are disconnected, placing the system in a power-saving state.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a portable device that functions as a wireless door key. [Background technology]

[0002] Patent Document 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), wireless communication is initiated to determine the position of the portable device. In Patent Document 1, the position of the portable device relative to the vehicle is determined by distance measurement communication using UWB (Ultra Wide Band) communication between a plurality of sensors mounted on the vehicle and the portable device. Patent Document 2 also discloses a portable device that operates on a secondary battery such as a lithium-ion battery.

[0003] Patent Document 3 discloses a configuration in which a power management IC (Integrated Circuit) is provided outside an MCU (Micro Control Unit) that provides functions in a wearable device. The power management IC plays a role in reducing the possibility of the secondary battery going into an over-discharge state by cutting off the power supply to the MCU when the output voltage of the secondary battery falls below a predetermined value. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7085526 [Patent Document 2] Japanese Patent Application Publication No. 2019-131967 [Patent Document 3] Patent No. 6221735 Summary of the Invention [Problem to be solved by the invention]

[0005] If a secondary battery becomes over-discharged, it may become impossible to recharge. Therefore, portable devices using secondary batteries require a mechanism to prevent the secondary battery from reaching an over-discharge state. However, in a configuration using a power supply monitoring IC, as in Patent Document 3, the introduction of a power supply monitoring IC increases manufacturing costs, which is an issue.

[0006] The present disclosure has been made in light of the above circumstances, and one of its objectives is to provide a technology for suppressing over-discharge of a secondary battery at a lower cost in a portable device that operates on a secondary battery. [Means for solving the problem]

[0007] The portable device disclosed herein is a portable device that functions as a wireless key for a door, operates on a secondary battery (41), and includes a communication unit (6) for wireless communication with a system that controls the locking status of the door, and a control circuit (10) that controls the communication unit. The control circuit includes a voltage monitoring terminal (17), which is an input terminal to which a signal indicating the output voltage of the secondary battery is input. Based on the signal input to the voltage monitoring terminal, the control circuit determines whether the output voltage is greater than a predetermined threshold value. If the output voltage of the secondary battery is greater than the threshold value, the control circuit sets the portable device to an ON state in which it can operate as a wireless key, whereas if the output voltage of the secondary battery is equal to or less than the threshold value, the control circuit sets the portable device to an OFF state in which it does not function as a wireless key.

[0008] According to the above configuration, the portable device is switched off when the output voltage of the secondary battery falls below a predetermined threshold. This stops the portable device from operating, reducing power consumption and reducing the risk of the secondary battery reaching an over-discharge state. Furthermore, in the above configuration, the main controller is responsible for monitoring the battery voltage, eliminating the need for a separate power supply monitoring IC. This reduces manufacturing costs compared to a configuration that includes a separate power supply monitoring IC from the main controller. In other words, the above configuration makes it possible to suppress over-discharge at lower cost.

[0009] 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. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing an overall view of a vehicle electronic key system; [Figure 2] FIG. 2 is a block diagram of the portable device. [Figure 3] FIG. 2 is a diagram showing the circuit configuration of a portion related to a battery. [Figure 4] 10 is a flowchart showing an example of the operation of the main controller in a normal state. [Figure 5] 10 is a flowchart showing the operation of the portable device in a power saving state. [Figure 6] 4 is a time chart showing the operation of the portable device with respect to charging and discharging of the battery. [Figure 7] 10 is a flowchart of a process for changing a stop threshold in response to a user operation. [Figure 8] 10 is a flowchart of a process for changing a stop threshold value according to the frequency of use of the portable device. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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 given the same reference numerals or names, and specific descriptions thereof may be omitted. When only a portion of a configuration is mentioned, descriptions given elsewhere may apply to other parts.

[0012] <Overall structure> As shown in Fig. 1, the electronic key system for a vehicle according to this embodiment includes a portable device 1 and an in-vehicle system 2. The portable device 1 is a wireless communication terminal carried by a user. The in-vehicle system 2 is a system mounted on the vehicle Hv. In the following description, the in-vehicle system 2 and the vehicle Hv may be interpreted as interchangeable.

[0013] The portable device 1 is linked to the in-vehicle system 2. That is, device information of the portable device 1 is registered in the in-vehicle system 2. 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 UUID (Universally Unique Identifier), etc. A plurality of portable devices 1 may be linked to the in-vehicle system 2.

[0014] The in-vehicle system 2 is a system that controls the locking state of the doors of the vehicle Hv by wirelessly communicating with the portable device 1. The in-vehicle system 2 may have a function of determining the position of the portable device 1 relative to the vehicle Hv by wirelessly communicating with the portable device 1. The portable device 1 and the in-vehicle system 2 may be configured to be capable of 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 the present disclosure, a signal transmitted and received via short-range communication may be referred to as a short-range communication signal or an SRWC signal.

[0015] The following describes the operation of each part using an example in which short-range communication (i.e., SRWC) is Bluetooth LE. Furthermore, the following assumes that the portable device 1 operates as a peripheral in Bluetooth LE, and the in-vehicle system 2 acts as a central. The roles of the portable device 1 and the in-vehicle system 2 in SRWC may be interchanged.

[0016] Furthermore, the portable device 1 and the in-vehicle system 2 may be configured to be able to perform ranging communication. In the present disclosure, ranging communication refers to wireless communication for measuring the distance between communication devices. The in-vehicle system 2 may include multiple anchors. The anchors are wireless communication modules for performing ranging communication with the portable device 1. The anchors may be distributed at multiple locations on the vehicle Hv, such as the left and right ends of the front bumper and the left and right ends of the rear bumper. The ranging communication may be performed using UWB (Ultra Wide Band) communication. The UWB communication may be wireless communication using the UWB-IR (Impulse Radio) method. Hereinafter, a UWB signal may be understood to be a signal exchanged using UWB communication.

[0017] In addition, the portable device 1 and the in-vehicle system 2 are configured to be able to perform 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 may be understood as communication over a distance of one-tenth or less of SRWC. In NFC, the portable device 1 is configured to operate as a terminal that returns data based on a request from the vehicle Hv, i.e., as a passive device (a so-called tag). The roles of the in-vehicle system 2 and the portable device 1 in NFC may be interchangeable.

[0018] <In-vehicle systems> First, the in-vehicle system 2 will be described. The in-vehicle system 2 periodically scans using power supplied from the in-vehicle battery and attempts to connect with the portable device 1. Scanning means that the in-vehicle system 2 is in a state where it can receive an SRWC signal. Upon receiving an advertising signal from the portable device 1, the in-vehicle system 2 transmits a connection request to the portable device 1 and establishes a communication connection with the portable device 1.

[0019] Upon establishing a communication connection with the portable device 1 via SRWC, the in-vehicle system 2 performs authentication processing via SRWC. The authentication processing may be understood as processing for determining whether the communication partner is a pre-registered terminal. The authentication processing may be performed using a challenge-response method. The in-vehicle system 2 and the portable device 1 may store data necessary for the authentication processing, such as an encryption key. Upon establishing a communication connection with the portable device 1 via SRWC, the in-vehicle system 2 causes each anchor to perform ranging communication with the portable device 1. The ranging communication may be communication for measuring the propagation time of radio waves from the anchor to the portable device 1 (in other words, the flight time). In the present disclosure, the value of the distance from the anchor to the portable device 1, calculated based on the flight time, is also referred to as the measured distance value. The in-vehicle system 2 acquires data indicating the results of the ranging communication (hereinafter, referred to as ranging result data) from each of the multiple anchors. The ranging result data includes the ID of the portable device 1 that performed the ranging and data indicating the distance from the anchor to the portable device 1.

[0020] The in-vehicle system 2 may determine the distance from the vehicle Hv to the portable device 1 (hereinafter also referred to as the device distance) based on the distance measurement result data provided from each anchor. The device distance may be the smallest value among the distance measurement values observed by multiple anchors. The in-vehicle system 2 may determine whether the portable device 1 is located inside the vehicle, in a nearby area, or in another area based on the distance measurement result data provided from each anchor. 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 in-vehicle system 2 may determine whether the portable device 1 is located in the nearby area by comparing the device distance with the operating distance.

[0021] The in-vehicle system 2 controls the unlocking / locking of the doors based on (i) the presence of the portable device 1 in the vicinity area, (ii) the portable device 1 has been authenticated, and (iii) a predetermined user action has been performed. The user action for locking / unlocking may be touching the door handle or waving a foot over a detection area formed below the door. The user action may be detected by an in-vehicle sensor such as a touch sensor.

[0022] The in-vehicle system 2 may include an in-vehicle HMI (Human Machine Interface) and an HCU (HMI Control Unit). The in-vehicle HMI includes a display and an input device disposed in the vehicle. The HCU is a computer that controls the HMI. The display may be a liquid crystal display, an organic light-emitting diode (OLED) display, or the like. The input device may be a touch panel, a steering switch, or the like. The display displays an image in response to an instruction signal input from the HCU. For example, the display displays a remaining power notification image or a key setting screen based on an instruction from the HCU. The remaining power notification image is an image indicating the battery voltage (i.e., the remaining power) of the portable device 1. The data indicating the remaining power may be a State Of Charge (SOC) value or a battery voltage value. The key setting screen is a screen for changing the operating conditions of the portable device 1. The key setting screen may include an operation button for changing the operation mode of the target portable device 1 to a long-term storage mode or a button for changing the stop threshold (described later). The in-vehicle system 2 transmits a command signal to the portable device 1 via SRWC in response to a user instruction received via the key setting screen. The portable device 1 changes the operation settings, such as the setting value of the stop threshold, based on the command signal received from the in-vehicle system 2.

[0023] <Portable device> The portable device 1 is a dedicated device that functions as a wireless key for the vehicle Hv. For example, the portable device 1 functions as a key for the vehicle Hv by performing wireless authentication using the in-vehicle system 2 and SRWC. The portable device 1 may be a device that is transferred to the owner along with the vehicle Hv when the vehicle Hv is purchased. The portable device 1 may be considered one of the accessories to the vehicle Hv. The portable device 1 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 1 may be called a smart key, a key fob, a key card, an access key, or the like. The portable device 1 of this embodiment does not have any physical buttons that can be pressed by the user, so-called push switches.

[0024] In other embodiments, the portable device 1 may be a general-purpose information processing terminal equipped with the SRWC function. The portable device 1 may be a smartphone or a wearable device. The portable device 1 may be equipped with one or more physical buttons. The portable device 1 may be referred to as a portable device, a user device, a key device, or the like.

[0025] 2, the portable device 1 includes an acceleration sensor 3, a power supply unit 4, a power receiving unit 5, a first wireless module 6, a second wireless module 7, a third wireless module 8, an indicator 9, and a main controller 10. In addition, the portable device 1 may include a clock oscillator that generates a clock for operating the main controller 10.

[0026] The main controller 10 is a microcomputer that controls the overall operation of the portable device 1. The main controller 10 corresponds to a control circuit. The main controller 10 includes a processor 11, a memory 12, a storage 13, and a communication interface 14. The processor 11 may be a CPU (Central Processing Unit). The memory 12 is a volatile storage medium such as RAM (Random Access Memory). The storage 13 is a recording device including a non-volatile storage medium such as flash memory. The storage 13 may include multiple types of storage media such as ROM (Read Only Memory) and flash memory. The communication interface 14 is a circuit module that allows the processor 11 to receive signals from other components such as the first wireless module 6 and transmit signals to other components.

[0027] The storage 13 stores a device control program. The device control program is a program including instructions for operating a computer as the main controller of the present disclosure. The storage 13 may also include an inspection data storage unit, a vehicle data storage unit, an owner data storage unit, an authentication data storage unit, and the like. The inspection data storage unit is an area where the date when the portable device 1 was inspected at a factory or the like is stored. The inspection of the portable device 1 may be an in-circuit test (ICT). The vehicle data storage unit is an area where data of the vehicle HV in which the portable device 1 is used (hereinafter, target vehicle data) is stored. The target vehicle data may include the identification number of the vehicle HV (hereinafter, vehicle ID). The vehicle ID may be a VIN (Vehicle Identification Number).

[0028] The owner data storage unit is a storage area in which information about the owner is stored. The information about the owner may be information about the owner device. The owner device is a communication terminal carried by the owner, different from the portable device 1. The owner device may be the owner's smartphone, etc. The information about the owner device may be, for example, the ID of the owner device obtained by a Bluetooth LE pairing process. The information about the owner may be the owner's name or phone number, etc. The authentication data storage unit may be an area in which data (e.g., an encryption key) used for wireless authentication with the in-vehicle system 2 is stored. In addition, the storage 13 may store a flag / code indicating whether or not the device is at the time of factory shipment, in other words, whether or not it is in the transportation phase.

[0029] As shown in FIG. 3 , the main controller 10 has a power supply terminal 15, a control terminal 16, and a voltage monitoring terminal 17 as terminals (in other words, pins / ports) for connection with other components. The power supply terminal 15 is a terminal (VDD in the figure) for receiving power required for the operation of the main controller 10. The power supply terminal 15 is electrically connected to the power supply unit 4 and a power receiving unit 5 (described later). Here, the term "electrical connection" may be understood as a connection using a conductive member such as a cable or a metal pattern provided on a substrate. The control terminal 16 is a terminal for outputting a signal for controlling the operation of a first regulator 42 (described later) to the first regulator 42. The control terminal 16 is electrically connected to the first regulator 42. The control terminal 16 may be referred to as a regulator control terminal or the like.

[0030] The voltage monitoring terminal 17 is a terminal to which a signal indicating the output voltage (hereinafter, battery voltage) of the battery 41 included in the power supply unit 4 is input. To prevent damage to the main controller 10, a voltage obtained by reducing the voltage of the battery 41 by a predetermined ratio (e.g., 0.5) may be input to the voltage monitoring terminal 17. The voltage reduction may be achieved by a voltage divider circuit including multiple resistors. A conversion circuit may be interposed between the voltage monitoring terminal 17 and the voltage output terminal (e.g., positive pole) of the battery 41. The conversion circuit may be a circuit (e.g., an IC) that inputs a digital signal indicating the battery voltage to the voltage monitoring terminal 17. The conversion circuit may also be a circuit that divides the battery voltage to a predetermined level, such as 1 / 2, 1 / 4, or 1 / 6, and outputs the divided voltage. In another embodiment, the voltage monitoring terminal 17 may be electrically connected to the voltage output terminal (e.g., positive pole) of the battery 41. In other words, the voltage of the battery 41 may be directly input to the voltage monitoring terminal 17. The voltage monitoring terminal 17 may be configured to receive a signal indicating the battery voltage.

[0031] The acceleration sensor 3 is a sensor that detects acceleration acting on the portable device 1. The acceleration sensor 3 may have multiple detection axes. For example, the acceleration sensor 3 may be a three-axis acceleration sensor. The acceleration sensor 3 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 main controller 10. The acceleration data may include detected acceleration values for each axis. The acceleration detected by the acceleration sensor 3 represents the magnitude of vibration acting on the portable device 1, in other words, the intensity of the user's movement. In the following description, acceleration may be interpreted as the maximum absolute value of the acceleration for each detection axis. The term "acceleration" may be replaced with "vibration" or "motion." The acceleration sensor 3 may be referred to as a vibration sensor or a motion sensor. In other embodiments, the acceleration sensor 3 may be a one-axis or two-axis acceleration sensor. When the acceleration sensor 3 detects acceleration equal to or greater than a predetermined wake threshold, it outputs a wake signal to the main controller 10. The wake signal may be a signal having a predetermined bit pattern or a signal indicating that acceleration equal to or greater than a predetermined value has been detected.

[0032] The power supply unit 4 includes a battery 41 and a first regulator 42. The battery 41 is a battery that stores power to be used for the operation of the portable device 1. The battery 41 is a chargeable and dischargeable battery (i.e., a secondary battery). For example, the battery 41 may be a lithium-ion secondary battery. Of course, the battery 41 may also be a lithium-ion polymer secondary battery, a nickel-cadmium battery, a nickel-metal hydride rechargeable battery, or the like. A discharge end voltage is set for the battery 41. The discharge end voltage is the lowest discharge voltage at which safe discharge can be performed. A state below the discharge end voltage corresponds to an over-discharge state. A main controller 10 (described later) monitors the output voltage of the battery 41 and controls the operating state of the portable device 1 so that the battery 41 does not reach an over-discharge state. Specifically, the main controller 10 controls the on / off of the first regulator 42 according to the output voltage of the battery 41.

[0033] The first regulator 42 is a circuit module responsible for supplying power to the main controller 10. The first regulator 42 generates and outputs a predetermined operating voltage suitable for the operation of the main controller 10 and other components from the power supply voltage output from the battery 41. The first regulator 42 corresponds to a power supply circuit. In this embodiment, the operating voltage may be, for example, 3 V. Of course, the operating voltage may be changed as appropriate. The first regulator 42 may be an IC chip. In this embodiment, the first regulator 42 is a linear regulator that operates even with a low input-output voltage difference, a so-called LDO (Low Dropout) regulator. Therefore, the first regulator 42 is represented as "LDO1" in the figure. An LDO may also be called a low-loss linear regulator or a low-saturation linear regulator. A linear regulator with a dropout voltage of 1 V or less may be considered an LDO. The first regulator 42 may also be called a first LDO, a main LDO, a main regulator, or a main supply circuit.

[0034] Compared to other types of linear regulators, LDOs have the advantages of being inexpensive, producing less noise, having a simple internal structure, and emitting less dark current. In a configuration in which an LDO is used as the first regulator 42, the output voltage has less noise, making it possible to operate a microcomputer such as the main controller 10 at a constantly stable voltage. In other embodiments, the first regulator 42 may be a linear regulator other than an LDO.

[0035] The power receiving unit 5 is configured to receive power transmitted from the wireless charger and charge the battery 41. The wireless charger may be a charging device independent of the portable device 1. The wireless charger may include a power transmitting coil, a drive circuit, and a power transmitting side power circuit. The wireless charger may be a device that charges the portable device 1 using power supplied from a power outlet at home, a mobile battery, an in-car battery, etc.

[0036] 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 power receiving unit 5 of the portable device 1 may be compatible with the Qi standard. In another embodiment, the portable device 1 may be configured to be capable of wireless charging using the AirFuel Inductive / Resonant method.

[0037] The power receiving unit 5 includes a receiving coil 51, a rectifier circuit 52, a charging control unit 53, and a second regulator 54 (LDO2 in the figure). The receiving coil 51 is a coil for receiving power wirelessly transmitted from the wireless charger by electromagnetically coupling with the transmitting coil of the wireless charger. The transmitting coil is also called a primary coil, and the receiving coil 51 is also called a secondary coil. The rectifier circuit 52 is a circuit for converting the power received by the receiving coil 51 into DC power. The output voltage of the rectifier circuit 52 is input to the charging control unit 53 and the second regulator 54.

[0038] The charging control unit 53 may be an IC that controls charging of the battery 41. The charging control unit 53 charges the battery 41 with power input from the rectifier circuit 52. The charging control unit 53 may include a DC / DC converter. The charging control unit 53 may be configured to be able to output a signal indicating a charging status (hereinafter, charging signal) to the main controller 10. The charging signal may be a signal indicating whether charging is in progress. If the charging control unit 53 is configured to be able to acquire the charging rate of the battery 41, the charging signal may include data indicating the charging rate. Furthermore, the charging signal may include data indicating the battery voltage. If the charging control unit 53 is configured to be able to measure the battery voltage, the main controller 10 may acquire the battery voltage from the charging control unit 53. The voltage monitoring terminal 17 may be an input / output terminal for communicating with the charging control unit 53.

[0039] The second regulator 54 is a linear regulator that generates an operating voltage based on power received from an external device. The second regulator 54 may include an input terminal, an output terminal, an enable terminal, a ground terminal, and the like. The input terminal of the second regulator 54 is a terminal to which the output voltage of the rectifier circuit 52 is input. The input terminal of the second regulator 54 is electrically connected to the output terminal of the rectifier circuit 52. The output terminal of the second regulator 54 is electrically connected to the power supply terminal 15 (VDD) of the main controller 10. The enable terminal of the second regulator 54 is electrically connected to the input terminal of the second regulator 54. As a result, the second regulator 54 is driven and operates to output an operating voltage when a voltage equal to or greater than a predetermined value is output from the rectifier circuit 52. In other words, the power receiving unit 5 is configured to charge the battery 41 and supply the operating voltage to the power supply terminal 15 based on receiving power from the wireless charger. The second regulator 54 corresponds to a temporary supply circuit.

[0040] The first wireless module 6 is a module for short-range communication provided in the portable device 1. The first wireless module 6 may include an SRWC antenna and an RF (Radio Frequency) core. The SRWC antenna is an antenna element for transmitting and receiving radio waves in the frequency band used for SRWC (here, 2.4 GHz band). The RF core is a circuit module that performs processing related to the transmission and reception of radio signals. The RF core demodulates the signal received by the SRWC antenna and provides it to the main controller 10. The RF core also modulates transmission data input from the main controller 10 and radiates it as radio waves from the SRWC antenna. The first wireless module 6 may include a matching circuit for matching the impedance between the antenna and the RF core.

[0041] The first wireless module 6 transmits and receives SRWC signals under the control of the main controller 10. For example, the main controller 10 is configured to be able to perform advertising in SRWC using the first wireless module 6. 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. When the in-vehicle system 2 receives an advertising signal from the portable device 1, it can transmit a connection request in response. When the main controller 10 receives a connection request from the in-vehicle system 2 via the first wireless module 6, it establishes a communication connection with the in-vehicle system 2. Based on the establishment of communication connection with the in-vehicle system 2, the main controller 10 can execute authentication processing using SRWC, ranging communication using UWB, and the like.

[0042] The second wireless module 7 is a communication module for performing UWB communication. The second wireless module 7 outputs received data to the main controller 10. The second wireless module 7 also transmits a UWB signal corresponding to transmission data input from the main controller 10. The second wireless module 7 is configured to start up, perform ranging communication, and stop operation based on instructions from the main controller 10.

[0043] The third wireless module 8 is a module for performing NFC communication. The third wireless module 8 is configured as a passive device that returns a signal according to the content of data received from an NFC reader installed in the vehicle Hv. The NFC reader of the vehicle Hv may be configured to attempt a communication connection with the portable device 1 by sending a polling command periodically or when a specific event occurs. The polling command is a command for checking whether the portable device 1 is located in a position where the NFC reader can communicate.

[0044] The third wireless module 8 is driven by the receiving power of the signal transmitted from the NFC reader, and generates and returns a response signal. The main controller 10 may be configured to be able to perform NFC authentication processing, which is user authentication using NFC. The NFC authentication processing corresponds to a backup (i.e., alternative authentication means) in case SRWC is not possible. Note that the third wireless module 8 is an optional element and may be omitted.

[0045] The indicator 9 is a light-emitting element for indicating the level of battery voltage, in other words, the remaining power. The remaining power may be the ratio of the actual remaining capacity to the fully charged capacity. The indicator 9 may be configured to be able to light up in multiple colors, for example, red, yellow, and green. The indicator 9 lights up based on instructions from the main controller 10. The main controller 10 may make the indicator 9 flash in red when it detects that the remaining power is less than a predetermined value (for example, 30%). Note that the indicator 9 is an optional element and may be omitted.

[0046] <Circuit configuration> 3, the first regulator 42 has a voltage input terminal 421 (IN in the figure), a voltage output terminal 422 (OUT), and an enable terminal 423 (EN) as signal terminals. The first regulator 42 also has a ground terminal (so-called GND). The voltage input terminal 421 is a terminal to which the output voltage of the battery 41 is input. The voltage input terminal 421 may be electrically connected to the positive electrode of the battery 41. The voltage output terminal 422 is a terminal that outputs the voltage (i.e., operating voltage) generated by the first regulator 42. The voltage output terminal 422 is electrically connected to the power supply terminal 15 of the main controller 10. For convenience, the signal line connecting the voltage output terminal 422 and the power supply terminal 15 is referred to as a power supply line Ln1.

[0047] The enable terminal 423 is a terminal that switches between enabling and disabling the first regulator 42. The operating state (enabled / disabled) of the first regulator 42 switches depending on the level of the signal input to the enable terminal 423. The disabled state of the first regulator 42 may be understood as a state in which the operation of the first regulator 42 is stopped. Specifically, the disabled state of the first regulator 42 may be a state in which the output voltage of the first regulator 42 is 0V. The enabled state of the first regulator 42 is a state in which the operating voltage is output.

[0048] The first regulator 42 is configured to operate when the input signal to the enable terminal 423 (hereinafter also referred to as the enable input voltage) is at a high level, and to stop operation when the enable input voltage is at a low level. In other words, the first regulator 42 is configured as a high-active regulator. As an example, the first regulator 42 may be configured to transition from an enabled state to a disabled state when the enable input voltage falls below 0.4 V, and to transition from the disabled state to the enabled state when the enable input voltage exceeds 0.9 V. A high level for the enable terminal 423 may be interpreted as a voltage of 0.4 V or 0.9 V or higher.

[0049] The enable terminal 423 is connected to ground via a first resistor 43 (R1 in the figure), which is a resistive element. The enable terminal 423 is also connected to the control terminal 16 (IO1 in the figure) of the main controller 10 via a second resistor 44 (R2 in the figure). The second resistor 44 is a resistive element different from the first resistor 43. As will be described later, the main controller 10 sets the output of the control terminal 16 to a high level as long as the battery voltage is equal to or higher than a predetermined value. Furthermore, if the main controller 10 detects that the battery voltage is lower than the predetermined value, it sets the output voltage of the control terminal 16 to a low level (e.g., 0 V). For convenience, the signal line connecting the control terminal 16 and the second resistor 44 is referred to as a control line Ln2. The high level for the control terminal 16 may be, for example, 3 V or 2 V. The high level of the control terminal 16 may be the same as the operating voltage.

[0050] When the output voltage of the control terminal 16 is at a high level, a voltage according to the resistance ratio between the second resistor 44 and the first resistor 43 is input to the enable terminal 423. By appropriately setting the resistance values of the first resistor 43 and the second resistor 44, when the output of the control terminal 16 is at a high level, the input voltage to the enable terminal 423 also becomes at a high level. For example, the resistance values of the first resistor 43 and the second resistor 44 may both be set to 500 kΩ.

[0051] The resistance values of the first resistor 43 and the second resistor 44 may be designed so that a voltage of 1.0 V or higher (e.g., 1 V, 1.5 V, or 3.0 V) is input to the enable terminal 423 when the output of the control terminal 16 is at a high level. When the resistance value of the first resistor 43 is R1 and the resistance value of the second resistor 44 is R2, R1 and R2 may be set to satisfy Vh×R1 / (R1+R2)>Ve. Vh is the voltage value (e.g., a target voltage) of the high-level signal output from the control terminal 16, and Ve is the voltage (e.g., 0.9 V) at which the first regulator 42 is enabled. For example, when the first resistor 43 and the second resistor 44 are both 500 kΩ and the output voltage of the control terminal 16 is 3 V, a high-level signal of approximately 1.5 V is input to the enable terminal 423, and the first regulator 42 is enabled.

[0052] When the output of the control terminal 16 is at a high level, a current flows from the control terminal 16 to ground via the second resistor 44 and the first resistor 43. By increasing the total resistance value of the first resistor 43 and the second resistor 44, the current flowing from the control terminal 16 to ground can be reduced. In other words, the larger the resistance value, the more the dark current can be reduced. For this reason, the first resistor 43 and the second resistor 44 may both be resistor elements with a resistance of 100 kΩ or more. Of course, the resistance values of the first resistor 43 and the second resistor 44 are not limited to 500 kΩ, and may be set to other values such as 700 kΩ, 800 kΩ, or 1 MΩ.

[0053] The resistance values of the first resistor 43 and the second resistor 44 may be the same or different. The resistance value of the first resistor 43 may be greater than the resistance value of the second resistor 44. For example, the resistance value of the first resistor 43 may be 1 MΩ, and the resistance value of the second resistor 44 may be 500 kΩ. Note that a resistor element with a resistance value of 1 MΩ or more may have a slightly higher failure rate due to a resistor break compared to a resistor element with a resistance value of less than 1 MΩ. For this reason, the first resistor 43 and the second resistor 44 may be resistor elements with a resistance value of less than 1 MΩ.

[0054] In this embodiment, the power supply line Ln1 is also connected to the control line Ln2 via the third resistor 45. In other words, the voltage output terminal 422, the power supply terminal 15, and the output terminal of the second regulator 54 are connected to the control line Ln2 via the third resistor 45. The resistance value of the third resistor 45 may be sufficiently smaller than those of the first resistor 43 and the second resistor 44. The resistance value of the third resistor 45 may be, for example, one-tenth of the resistance value of the first resistor 43. The resistance value of the third resistor 45 may be, for example, 10 kΩ or 22 kΩ.

[0055] When the first regulator 42 is enabled, the operating voltage is input from the first regulator 42 to the power supply terminal 15. Therefore, the main controller 10 is activated when the acceleration sensor 3 detects vibration, and is able to transmit advertisements and perform other operations. Note that when the first regulator 42 is enabled, the output level of the control terminal 16 is 3V, so the potential difference between the control terminal 16 and the power supply line Ln1 can be considered to be substantially zero. Therefore, the current flowing through the third resistor 45 can be ignored.

[0056] Furthermore, when the first regulator 42 is disabled and the portable device 1 is not being wirelessly charged, the input voltage to the power terminal 15 is 0V, and the main controller 10 is in a power-off state. That is, the main controller 10 stops operating. When the main controller 10 stops, the output of the control terminal 16 is in a high-impedance state, but the control terminal 16 is connected to ground via the first resistor 43 and the second resistor 44. That is, the control line Ln2 is pulled down. Therefore, the potential of the control line Ln2 is maintained at 0V even while the main controller 10 is powered off. Because the enable terminal 423 is also connected to ground via the first resistor 43, the enable input voltage is also maintained at 0V (i.e., low level) even while the main controller 10 is powered off. Therefore, the first regulator 42 remains in a power-off state.

[0057] However, if the main controller 10 is reset while the first regulator 42 is operating, the control terminal 16 may temporarily enter a high-impedance state. In a configuration in which the power supply line Ln1 and the control line Ln2 are not connected by the third resistor 45 (hereinafter, the comparative configuration), the enable input voltage is pulled down to a low level when the main controller 10 is reset. As a result, in the comparative configuration, the first regulator 42 stops when the main controller 10 is reset, as described below. If the first regulator 42 stops, the main controller 10 also stops, as described below, requiring the user to perform a recovery procedure using a wireless charger, as described below. Such an unintended stop of the first regulator 42 can occur not only due to a controller reset, but also due to a momentary error in the circuitry connected to the control terminal 16.

[0058] To address this issue with the comparative configuration, in this embodiment, the voltage output terminal 422 of the first regulator 42 is connected to the control line Ln2 (specifically, the control terminal 16) via a third resistor 45. Therefore, even if the output of the control terminal 16 temporarily enters a high-impedance state due to a reset of the main controller 10 or the like, the potential of the control line Ln2 is pulled to the output (high level) of the first regulator 42 and maintained at a high level. Accordingly, the enable input voltage is also maintained at a high level. Therefore, even if a reset of the main controller 10 or the like occurs, the driving of the first regulator 42 can be maintained. As described above, the third resistor 45 can function as a pull-up resistor element during a reset. Note that the third resistor 45 is an element for dealing with resets and is not an essential element. If stopping the first regulator 42 due to a reset of the main controller 10 is permitted, the third resistor 45 may be omitted.

[0059] Additionally, as will be described later, the main controller 10 acquires data indicating the voltage of the battery 41 based on a signal received at the voltage monitoring terminal 17. The main controller 10 then determines whether the battery voltage is equal to or lower than a predetermined shutdown threshold. If the main controller 10 determines that the battery voltage is equal to or lower than the shutdown threshold, it sets the output of the control terminal 16 to a low level. When the output of the control terminal 16 becomes low, the current based on the output voltage of the first regulator 42 flows to ground via the control terminal 16 without passing through the second resistor 44, which has a relatively high resistance value. When the output of the control terminal 16 is low, no current flows through the first resistor 43, so the enable input voltage becomes low and the first regulator 42 is shut down. With the first regulator 42 shut down (disabled), power is no longer supplied to the main controller 10, and the main controller 10 is also powered off. That is, by setting the output of the control terminal 16 to a low level, the main controller 10 transitions to a powered off state. When the main controller 10 is powered off, power consumption can be reduced.

[0060] <Mobile device operation mode> The portable device 1 has a normal state and a power saving state as states (modes) for setting the power supply. The normal state is an operation mode applied in everyday use cases. In the normal state, the first regulator 42 is enabled. In the normal state, power from the battery 41 is supplied to the main controller 10 via the first regulator 42. In the normal state, the portable device 1 functions as a wireless key for the vehicle Hv. That is, in the normal state, the main controller 10 attempts to establish a wireless connection with the vehicle Hv based on the acceleration sensor 3 outputting a wake signal. The normal state corresponds to the on state.

[0061] On the other hand, the power saving state corresponds to a state in which power from the battery 41 is not supplied to the main controller 10, that is, a state in which the main controller 10 is disconnected from the battery 41. The power saving state may be understood as a state in which the first regulator 42 is disabled and no operating voltage is input to the power supply terminal 15 of the main controller 10. In the power saving state, even if vibrations corresponding to accelerations equal to or greater than the wake threshold act on the portable device 1, the main controller 10 does not start up. In other words, in the power saving state, the portable device 1 does not function as a wireless key for the vehicle Hv. The power saving state corresponds to the off state.

[0062] In the normal state, the main controller 10 samples the battery voltage at a predetermined timing. When the main controller 10 detects that the battery voltage is equal to or lower than the stop threshold, it inputs a low-level signal to the enable terminal 423 to stop the first regulator 42 and transition the portable device 1 from the normal state to the power-saving state. Inputting a low-level signal to the enable terminal 423 corresponds to dropping the output of the control terminal 16 to a low level.

[0063] In the power-saving mode, the main controller 10 itself stops when the first regulator 42 stops, and therefore the main controller 10 cannot voluntarily output a high-level signal from the control terminal 16. Return from the power-saving mode to the normal mode is achieved by charging using a wireless charger. Upon receiving power from the wireless charger, the second regulator 54 supplies an operating voltage (high-level signal) to the power supply line Ln1. The power supplied from the second regulator 54 to the power supply line Ln1 starts up the main controller 10. After completing the startup process, the main controller 10 sets the output of the control terminal 16 to a high level, thereby returning the portable device 1 to the normal mode. In this way, the first regulator 42 is enabled as a trigger for wireless charging, and the portable device 1 transitions to the normal mode.

[0064] <Main controller operation under normal conditions> While the portable device 1 is set to the normal state, it transitions between two main states: an active state and a sleep state. The active state may be further divided into an advertising state and a connected state. The trigger for the state transition may be the detection of vibration, connection / disconnection of communication with the vehicle Hv, etc. In the present disclosure, the transition of the portable device 1 from the sleep state to the active state is also referred to as waking. Waking of the portable device 1 corresponds to the main controller 10 becoming active.

[0065] The active state is a state in which the main controller 10 can perform various calculations, including communications such as transmitting advertising signals. The active state may be interpreted as a state in which a clock is input to the main controller 10. The advertising state, which is included in the active state, is a state in which the main controller 10 performs advertising using the first wireless module 6 at a predetermined advertising interval. Immediately after waking, the portable device 1 enters the advertising state. The advertising state may be interpreted as a state in which the vehicle Hv is being searched for by transmitting advertising signals. The advertising interval may be increased as the time elapsed since waking increases. While the portable device 1 is in the advertising state, the main controller 10 may set the second wireless module 7 to a sleep state. The sleep state of the second wireless module 7 may be a state in which some or all of the functions of the second wireless module 7 are stopped to reduce power consumption.

[0066] The connection state included in the active state is a state in which the portable device 1 and the vehicle Hv are connected for communication via SRWC. The portable device 1 transitions to the connection state when it receives a response (e.g., a connection request) from the vehicle Hv in response to the advertisement. While in the connection state, the portable device 1 periodically performs data communication with the vehicle Hv. The main controller 10 may transition the second wireless module 7 to a state in which it can transmit and receive UWB signals, based on the fact that the first wireless module 6 has connected to the in-vehicle system 2 via SRWC. While in the connection state, the main controller 10 may perform ranging communication with the in-vehicle system 2 at predetermined intervals using the second wireless module 7, provided that the battery voltage is equal to or higher than a predetermined value. The connection state may include a ranging state in which the second wireless module 7 periodically performs ranging communication, and a sleep state in which periodic ranging communication is not performed.

[0067] The sleep state is a state in which the main controller 10 is inactive (in other words, a standby state). The sleep state may also be referred to as a standby state. In the sleep state, some or all of the functions of the main controller 10 are stopped. The sleep state may be understood as a state in which power consumption is slightly higher than in the power-off state but lower than in the active state. The sleep state is a state in which transition to the active state can be made relatively quickly. For example, the sleep state may be a state in which initialization processing associated with startup is completed, i.e., a state in which power supply to the processor 11 is suspended while data used for communication with the in-vehicle system 2 and the like remains in the memory 12 / storage 13. The sleep state may be a state in which clock supply to the processor 11 is stopped. In the sleep state, the second wireless module 7 and the like may be stopped. In other words, the portable device 1 in the sleep state may be unable to communicate with the vehicle Hv.

[0068] Even in the sleep state, the power receiving unit 5 and the third wireless module 8 can be driven by power received from an external source. For example, the charging control unit 53 may be configured to charge the battery 41 when a voltage equal to or greater than a predetermined value is input from the rectifier circuit 52, even in the sleep state.

[0069] The portable device 1 of this embodiment is configured to transition to an active state (specifically, an advertising state) when acceleration equal to or greater than a predetermined wake threshold is detected in a sleep state. That is, the main controller 10 is configured to wake up and start advertising when a wake signal is input from the acceleration sensor 3.

[0070] The portable device 1 transitions to the sleep state when, in the active state, a state in which acceleration equal to or greater than the sleep threshold is not detected continues for a predetermined standby time. The sleep threshold may be the same as the wake threshold or may be smaller than the wake threshold. For example, the sleep threshold may be a value equivalent to 50% or 25% of the wake threshold. Hereinafter, a state in which the acceleration sensor 3 does not detect acceleration equal to or greater than the sleep threshold is also referred to as a stationary state. The standby time may be set to 90 seconds, 120 seconds, 180 seconds, or the like. Furthermore, the portable device 1 may transition from the connected state to the sleep state when, after entering the connected state, a state in which it is unable to receive an SRWC signal from the vehicle Hv continues for a predetermined time, or when it receives a disconnection request signal from the vehicle Hv requesting disconnection.

[0071] The stop threshold is designed based on the discharge characteristics of the power supply unit 4. The stop threshold may be 3.4 V, 3.6 V, 3.8 V, etc. The stop threshold may be set to a value greater than the discharge end voltage. The stop threshold may be understood as a parameter that expresses the remaining power of the battery 41 for transitioning to a power saving state as a voltage value.

[0072] 4 is a flowchart showing the operation of the main controller 10 in relation to mode switching in the normal state. The series of processes shown in FIG. 4 can be called a mode control process. The mode control process may include steps S101 to S110 as shown in FIG. 4. The main controller 10 as the entity executing the following processes may be replaced with the processor 11 or the portable device 1.

[0073] The flow shown in Fig. 8 may be started when a wake signal is input from the acceleration sensor 3 to the main controller 10, in other words, when the acceleration sensor 3 detects acceleration equal to or greater than a wake threshold. Step S101 is a step in which the main controller 10 executes wake-up processing. The wake-up processing is processing for transitioning from a sleep state to an active state (more specifically, an advertising state). The wake-up processing may include starting clock supply to the processor 11. When step S101 is completed, the processing proceeds to step S102.

[0074] In step 102, the main controller 10 refers to the storage 13 and determines whether the current time corresponds to the shipping phase. Whether the current time corresponds to the shipping phase may be determined by referring to data stored in the storage 13. For example, the main controller 10 may determine whether the current time corresponds to the shipping phase based on whether information about the owner (e.g., information about the owner device) is stored in the owner data storage unit of the storage 13. If information about the owner device is stored in the storage 13, the main controller 10 determines that the current time is not the shipping phase (NO in S102) and proceeds to step S104. On the other hand, if information about the owner device is not stored in the storage 13, the main controller 10 determines that the current time corresponds to the shipping phase and proceeds to step S103. Note that if information about the owner is not stored in the storage 13, data indicating that the information about the owner is not registered (e.g., NULL or a predetermined code) is stored in the area where the information about the owner is stored. The data / code indicating that the owner information is not registered corresponds to data indicating that the product is shipped from the factory. The step of determining whether the current time corresponds to the shipping phase is optional and may be omitted. The main controller 10 may be configured to execute step S104 when a wake signal is input from the acceleration sensor 3.

[0075] Step S103 is a step in which the main controller 10 executes processing for transitioning to a power saving state. That is, in step S103, the main controller 10 sets the output level of the control terminal 16 to a low level, thereby stopping the first regulator 42. When step S103 is completed, this flow ends.

[0076] Step S104 is a step in which the main controller 10 acquires the battery voltage. The main controller 10 may determine the battery voltage based on a signal received at the voltage monitoring terminal 17. The battery voltage value acquired in step S104 is also referred to as the observed battery voltage value. After step S102 is completed, the process proceeds to step S103.

[0077] In step S105, the main controller 10 determines whether the battery voltage is greater than the stop threshold. In the figure, "Vb" represents the observed value of the battery voltage, and "Vth" represents the stop threshold. If the battery voltage is greater than the stop threshold (YES in S105), the process proceeds to step S107. On the other hand, if the battery voltage is equal to or less than the stop threshold (NO in S105), the process proceeds to step S106.

[0078] Step S106 is a step for determining whether the battery 41 is currently being charged using the wireless charger. The main controller 10 may determine whether the battery 41 is being charged based on a charging signal received from the charging control unit 53. In another aspect, the main controller 10 may determine whether the battery 41 is being charged based on the transition of the battery voltage observed within the past predetermined time. The main controller 10 may determine that the battery 41 is being charged if the battery voltage is on an increasing trend. The main controller 10 may determine that the battery 41 is not being charged if the battery voltage is not on an increasing trend.

[0079] If the main controller 10 determines in step S106 that the battery 41 is being charged (YES in S106), it executes step S107. On the other hand, if the main controller 10 determines in step S106 that the battery 41 is not being charged (NO in S106), it executes step S103. That is, the main controller 10 of this embodiment is configured to stop the first regulator 42 when the battery voltage is equal to or lower than the stop threshold and the battery is not being charged. Stopping the first regulator 42 may be achieved by setting the output of the control terminal 16 to a low level.

[0080] Furthermore, the main controller 10 does not stop the first regulator 42 while the battery is being charged, even if the battery voltage is below the stop threshold. During wireless charging, the main controller 10 continues to set the output of the control terminal 16 to a high level (i.e., does not set it to a low level) even if the battery voltage is below the stop threshold. This is because there is no need to stop the first regulator 42 while charging.

[0081] Step S107 is a step in which the main controller 10 executes processing according to the situation as an operation in the active state. For example, in step S107, the main controller 10 may transmit an advertising signal if it is not connected to the in-vehicle system 2. Also, in step S107, the main controller 10 may establish a communication connection with the in-vehicle system 2 based on receiving a connection request from the in-vehicle system 2. A state in which the portable device 1 and the vehicle Hv are communicatively connected (i.e., a connected state) may be interpreted as a state in which an SRWC link is established. In the connected state, the portable device 1 may transmit and receive wireless signals for communication confirmation at predetermined intervals and may perform encrypted data communication with the vehicle Hv. Based on the establishment of a communication connection with the vehicle Hv, the main controller 10 may activate the second wireless module 7 and periodically perform ranging communication with the vehicle Hv using the second wireless module 7 (S16). Additionally, the main controller 10 may transmit a battery status report, which is data indicating the battery voltage, to the vehicle Hv via SRWC, based on the establishment of a communication connection with the vehicle Hv via SRWC.

[0082] The main controller 10 periodically executes the determination process of step S108 in parallel with the process of step S107. Step S108 is a step for determining whether a certain time has passed since the battery voltage was last acquired. The main controller 10 acquires the battery voltage at a certain sampling interval in the active state. The sampling interval may be 30 seconds, 60 seconds, 90 seconds, or the like. If a certain time has passed since the battery voltage was last acquired (YES in S108), the main controller 10 re-executes the process from S104 onwards. The main controller 10 may transmit a battery status report every time the main controller 10 acquires the battery voltage. Furthermore, if a certain time has not passed since the battery voltage was last acquired (NO in S108), the main controller 10 executes step S109 in parallel with the process of step S107. The determination processes of steps S108 and S109 may be included in step S107.

[0083] Step S109 is a step in which the main controller 10 determines whether or not a sleep condition is satisfied. The sleep condition is a condition under which the portable device 1 transitions from an active state to a sleep state. The sleep condition may be that the acceleration sensor 3 of the portable device 1 does not detect an acceleration equal to or greater than a sleep threshold value for a standby time. Alternatively, the sleep condition may be that the communication connection with the vehicle Hv is disconnected.

[0084] If the sleep condition is not met, for example, if the duration of the stationary state has not reached the standby time, the main controller 10 maintains the active state and repeats steps S107 to S109. If the sleep condition is met in step S109, that is, if the duration of the stationary state has reached the standby time, the main controller 10 performs processing to transition to the sleep state (S110). The processing to transition to the sleep state may be, for example, stopping the clock oscillator.

[0085] <Returning from power saving mode to normal mode> FIG. 5 is a flowchart illustrating the operation of the portable device 1 when returning from the power-saving state to the normal state. Returning from the power-saving state to the normal state may include four steps, S201 to S204. Step S201 is a step in which the power receiving unit 5 receives power from the wireless charger. Step S202 is a step in which the power receiving unit 5 receives power from the wireless charger, and the second regulator 54 is driven to output an operating voltage (high-level signal) to the power supply line Ln1. Step S203 is a step in which the main controller 10 is started up based on the power supplied from the second regulator 54 to the power supply line Ln1. Until the start-up (in other words, initialization) of the main controller 10 is completed in step S203, the control terminal 16 is in a high-impedance state. Once the start-up of the main controller 10 is completed, the main controller 10 starts outputting a high-level signal from the control terminal 16. Step S204 is a step in which the first regulator 42 starts driving based on the high-level signal output from the control terminal 16 / second regulator 54.

[0086] In a configuration including the third resistor 45 as in this embodiment, current can flow from the second regulator 54 to the enable terminal 423 and the first resistor 43 via the third resistor 45 and the second resistor 44 during initialization of the main controller 10. This is because the control terminal 16 is in a high-impedance state during initialization of the main controller 10. At this time, due to the principle of voltage division, the enable input voltage can become high. That is, the configuration including the third resistor 45 has the advantage that wireless charging triggers the start of operation of the first regulator 42 before initialization of the main controller 10 is complete. In a configuration including the third resistor 45, the first regulator 42 is enabled by wireless charging. In another embodiment without the third resistor 45, the first regulator 42 starts operating when startup of the main controller 10 is completed and a high-level signal is output from the control terminal 16.

[0087] FIG. 6 is a time chart showing the operation of the portable device 1 under the control of the first regulator 42. (A) in FIG. 6 shows the change in battery voltage over time. "Vth" in the figure represents the stop threshold. (B) shows the state change of the main controller 10. "SLEEP" in the figure represents the sleep state, "ACTIVE" represents the active state, "OFF" represents the power is off, and "INIT" represents the initialization process being performed. (C) shows the output voltage of the control terminal 16. "HI" in the figure represents the high level, and "LO" represents the low level. Also, "Hi-Z" represents the high impedance state.

[0088] (D) in Figure 6 shows the transition of the voltage applied to the control line Ln2. In the figure, "Vd" shows the disable voltage, which is the voltage at which the first regulator 42 stops operating, and "Ve" shows the enable voltage, which is the voltage at which the first regulator 42 starts operating. As mentioned above, the disable voltage is, for example, 0.4V, and the enable voltage is, for example, 0.9V. (E) shows the transition of the enable input voltage. (F) shows the transition of the output voltage of the first regulator 42. (G) shows the transition of the output voltage of the second regulator 54.

[0089] Time t1 in FIG. 6 is the time when the portable device 1 vibrates and the acceleration sensor 3 outputs a wake signal to the main controller 10. Upon receiving the wake signal, the main controller 10 wakes up as shown in (B) and transitions to an active state. Time t2 is the time when the battery voltage reaches the shutdown threshold (Vth). When the main controller 10 detects that the battery voltage has fallen below the shutdown threshold, it drops the output of the control terminal 16 from high to low as shown in (C). This causes the voltage applied to the control line Ln2 to also drop to low as shown in (D). Thereafter, the enable input voltage decreases at a predetermined rate, and the first regulator 42 stops operating when the enable input voltage falls below the disable voltage (t3 in the figure). When the operation of the first regulator 42 stops, the output voltage of the first regulator 42 goes low. Therefore, the main controller 10 also enters a power-off state, and the control terminal 16 enters a high-impedance state. Although the diagram shows the enable voltage decreasing gradually, in reality it may decrease sharply at a rate that depends on the circuit characteristics.

[0090] When the main controller 10 is powered off, the control terminal 16 also enters a high impedance state. However, because the control line Ln2 is connected to ground via the first resistor 43 and the second resistor 44, the voltage applied to the control line Ln2 is maintained at a low level. Therefore, even while the main controller 10 is stopped, the first regulator 42 remains stopped, and the power-saving state is maintained.

[0091] Time t4 is the time when charging of the portable device 1 using the wireless charger begins. Because the second regulator 54 starts to output a high level based on the power received wirelessly, the main controller 10 is powered on as shown in (B) and starts initialization processing (INIT in the figure). In response to the power supply line Ln1 going high, the voltage of the control line Ln2 also goes high. Furthermore, in response to the voltage of the control line Ln2 going high, the enable input voltage also goes high.

[0092] At a subsequent time t5, the main controller 10 is initialized (i.e., started up). When the main controller 10 completes the initialization, it sets the output of the control terminal 16 to a high level, as shown in (C). In response to the enable input voltage becoming high, the first regulator 42 begins to output a high-level signal.

[0093] <Effects> Here, as a comparative example, the advantages and effects of the portable device 1 will be explained using a configuration in which a power supply monitoring IC is installed outside the microcomputer corresponding to the main controller 10. The power supply monitoring IC is a power supply control IC that constantly monitors the battery voltage. In the comparative example, the power supply monitoring IC turns off the power supply to the microcomputer when the battery voltage falls below a predetermined value, and turns on the power supply to the microcomputer when the battery voltage exceeds the predetermined value. The power supply monitoring IC periodically or constantly monitors the battery voltage using the battery power even while the microcomputer is powered off.

[0094] In contrast to such a comparative example, in the portable device 1, the main controller 10 itself monitors the battery voltage. Therefore, in the portable device 1, there is no need to place a power supply monitoring IC outside the main controller 10. Therefore, the manufacturing cost can be reduced compared to the comparative example.

[0095] Furthermore, in general, the stop threshold of a power supply monitoring IC depends on the hardware specifications, and the manufacturer of the portable device 1 has the problem that the stop threshold cannot be freely adjusted. In contrast, in the portable device 1 of this embodiment, the stop threshold can be adjusted by software / setting file / parameters of the main controller 10. Therefore, the portable device 1 of this embodiment has the advantage over the comparative example that the stop threshold can be easily changed.

[0096] The portable device 1 also includes a second regulator 54 that converts charging power received by the power receiving unit 5 from the outside into an operating voltage and supplies the operating voltage to the main controller 10. In the portable device 1, the second regulator 54 supplies power to the main controller 10 in response to wireless charging, which starts up the main controller 10 and starts driving the first regulator 42. This configuration has the advantage that the portable device 1 can return to the normal state from the power saving state without a power supply monitoring IC.

[0097] Furthermore, the portable device 1 includes a third resistor 45 that connects the power supply line Ln1 and the control line Ln2. As a result, while the main controller 10 is being reset, a divided voltage of the output voltage of the first regulator 42 acts on the enable terminal 423, and the enable input voltage is maintained at a high level. Even while the control terminal 16 is temporarily in a high impedance state due to the reset of the main controller 10, the first regulator 42 can continue to operate. Therefore, power supply to the main controller 10 can be maintained even while the main controller 10 is being reset.

[0098] Furthermore, when the portable device 1 is woken up, it determines whether it is in the shipping phase, and if it is determined to be in the shipping phase, it transitions to a power-saving state. This reduces unnecessary wake-ups during transportation, thereby reducing power consumption.

[0099] <Modification> The stop threshold may be provided in multiple stages. For example, the stop threshold may be configured so that the user can select from two thresholds, a first threshold and a second threshold. The first threshold may be a value relatively smaller than the second threshold. The first threshold may be interpreted as a stop threshold for the portable device 1 that is used regularly (daily) by the user. The second threshold may be a stop threshold applied when the portable device 1 is stored for a long period of time. The higher the set value of the stop threshold, the earlier the device will transition to the power-saving state. Therefore, the higher the set value of the stop threshold, the less likely the battery 41 will be over-discharged. On the other hand, the higher the set value of the stop threshold, the more likely the device will transition to the power-saving state, which may encourage the user to wirelessly charge the portable device 1 more frequently. From the perspective of user convenience, a lower stop threshold is preferable. The setting of the stop threshold may be changed by the user using the in-vehicle HMI.

[0100] For example, when the in-vehicle system 2 is connected to the portable device 1 via SRWC for communication, it displays a key setting screen based on a user's operation. The key setting screen may include a first button for setting the portable device 1 as a daily use key and a second button for setting the portable device 1 as a storage key. The daily use key here refers to a portable device 1 that the user uses regularly (daily). The storage key refers to a portable device 1 that is not used daily, such as a spare portable device 1, or a portable device 1 that is stored for a long period of time in a drawer or the like.

[0101] FIG. 7 is a flowchart showing the operation of the entire system according to this modified example. When the first button is pressed on the key setting screen (YES in S311), the in-vehicle system 2 transmits a command signal to the portable device 1 via SRWC instructing the portable device 1 to set the stop threshold to the first threshold. When the second button is pressed on the key setting screen (NO in S311), the in-vehicle system 2 transmits a command signal to the portable device 1 via SRWC instructing the portable device 1 to set the stop threshold to the second threshold. The portable device 1 changes the setting value of the stop threshold based on the command signal received from the in-vehicle system 2. That is, when the main controller 10 receives a command signal to set the stop threshold to the first threshold, it rewrites the setting value of the stop threshold in the storage 13, etc. to the first threshold. When the main controller 10 receives a command signal to set the stop threshold to the second threshold, it rewrites the setting value of the stop threshold in the storage 13, etc. to the second threshold. This configuration allows the conditions for transitioning the portable device 1 to the power-saving state to be matched to the manner in which the user uses the portable device 1.

[0102] The above describes a configuration in which the user can change the value of the stop threshold using an in-vehicle HMI. However, the HMI for changing the operation settings of the portable device 1 is not limited to the in-vehicle HMI. The portable device 1 may be configured to be able to change the value of the stop threshold based on a signal from an owner device. The owner device, like the in-vehicle HMI, may also be configured to be able to display a key setting change screen and send a command signal in response to a user operation on that screen. Furthermore, the number of stop thresholds that can be set on the portable device 1 may be three or more. The portable device 1 may also be configured to be able to allow the user to set the stop threshold to any value via the key setting screen.

[0103] Although the above describes a pattern in which the stop threshold is changed based on a user operation, the in-vehicle system 2 or the portable device 1 may be configured to automatically change the set value of the stop threshold based on the frequency of use of the portable device 1. For example, the portable device 1 and the in-vehicle system 2 may be configured to automatically switch the stop threshold from the first threshold to the second threshold by executing steps S321 to S326 shown in FIG.

[0104] Step S321 is a step in which the portable device 1 connects to the in-vehicle system 2 via SRWC. Step S322 is a step in which the in-vehicle system 2 records the date and time when the in-vehicle system 2 communicates with the portable device 1. Step S322 may be interpreted as a step in which the connection history is updated. The fact that the portable device 1 has communicated with the in-vehicle system 2 means that the user has approached the vehicle Hv while carrying the portable device 1. In other words, the frequency of connection between the portable device 1 and the in-vehicle system 2 indirectly indicates how frequently the user uses the portable device 1. The more frequent the communication connection and the shorter the interval between communication connections, the higher the frequency of use. Connection history data indicating the date and time of past connections may be stored in any recording device provided in the in-vehicle system 2. The connection history data may be stored separately for each portable device 1. When portable devices 1a and 1b are registered in the in-vehicle system 2, the connection history data for portable device 1a and the connection history data for portable device 1b may be separate.

[0105] Step S323 is a step in which the in-vehicle system 2 determines whether the portable device 1 is used infrequently based on the connection history data. The in-vehicle system 2 may determine that the portable device 1 is used infrequently if the number of connections within a certain period (e.g., three months) is less than a certain value. The in-vehicle system 2 may also determine that the portable device 1 is used infrequently if the average connection interval is equal to or greater than a certain value (e.g., 15 days). The connection interval may be expressed as the number of days from the previous communication connection to the next communication connection.

[0106] When the in-vehicle system 2 determines from the connection history data that the portable device 1 is used infrequently (YES in S323), it transmits a threshold change command to the portable device 1 (S324). The threshold change command transmitted in step S324 may be a command signal instructing the portable device 1 to set the stop threshold to the second threshold. Upon receiving the threshold change command (S325), the portable device 1 changes the set value of the stop threshold in accordance with the command (S326).

[0107] According to the above configuration, the level of the stop threshold is automatically adjusted according to the frequency of use of the portable device 1. This improves user convenience while further reducing the risk of the battery 41 becoming over-discharged. Note that, although the above describes a pattern in which the in-vehicle system 2 records the connection history and controls the stop threshold, the portable device 1 may also be the entity that manages the connection history. The portable device 1 may be configured to save and update connection history data and dynamically change the stop threshold according to the frequency of use. Note that the portable device 1 does not need to have a clock function. The portable device 1 may be configured to obtain date information from the in-vehicle system 2 and record it in the storage 13 when connected to the in-vehicle system 2.

[0108] The above control for setting the stop threshold may be performed using the frequency at which the in-vehicle system 2 receives a wake signal from the portable device 1, instead of the frequency at which communication is established. Also, the frequency at which the portable device 1 is used may be determined based on data indicating the frequency at which the main controller 10 detects acceleration equal to or greater than a predetermined value. Specifically, the portable device 1 may notify the in-vehicle system 2 of this fact every time acceleration equal to or greater than the sleep threshold is detected in the active state. The more times acceleration equal to or greater than the sleep threshold is detected, the more frequently the portable device 1 is used. The in-vehicle system 2 may rewrite the stop threshold using NFC instead of SRWC.

[0109] Furthermore, the data for estimating the frequency of use of the portable device 1 is not limited to data indicating the frequency of connection. The portable device 1 may estimate the duration of the sleep state based on the voltage drop amount, which is the difference between the battery voltage value when it was last woken up and the battery voltage value when it was currently woken up. A longer duration of the sleep state indicates a lower frequency of use. The main controller 10 may execute a process to increase the stop threshold when the voltage drop amount is equal to or greater than a predetermined value, or when the duration of the sleep state determined based on the voltage drop amount is equal to or greater than a predetermined value. For example, the main controller 10 may increase the stop threshold from a first threshold to a second threshold when the voltage drop amount is equal to or greater than a predetermined value.

[0110] As described in the embodiment, when the main controller 10 receives a wireless charging signal and starts up, it may set the output level of the control terminal 16 to high, regardless of the battery voltage at that time. In another embodiment, the main controller 10 may execute a process to return to the normal state when it detects that the battery voltage has returned to a predetermined return threshold or higher through wireless charging. The process to return to the normal state is a process to set the output level of the control terminal 16 from low to high. The return threshold may be the same value as the stop threshold, or may be set to a value greater than the stop threshold by a predetermined amount.

[0111] When the portable device 1 is communicatively connected to the in-vehicle system 2 via SRWC, the portable device 1 may transmit data indicating the remaining power to the in-vehicle system 2 via SRWC. Upon receiving the data indicating the remaining power from the portable device 1, the in-vehicle system 2 may display a remaining power notification image on the display. In other words, when the portable device 1 is communicatively connected to the vehicle Hv via SRWC, the portable device 1 may transmit data indicating the remaining power to the vehicle Hv via SRWC and display a remaining power notification image on the display. This configuration makes it easy for the user to recognize the remaining power of the portable device 1.

[0112] The mode of the remaining power notification image may be changed depending on the remaining power. For example, the in-vehicle system 2 may change the display in the order of "High," "Mid," "Low," and "Critical" as the remaining power decreases. The in-vehicle system 2 may blink the remaining power notification image when the remaining power falls below an emergency value. The emergency value may be a value that is a predetermined amount greater than the stop threshold.

[0113] The above control may be performed using the remaining power (i.e., SOC) instead of the output voltage. Step S105 may be a step of determining whether the remaining power exceeds the stop threshold. In the present disclosure, the expression "when the battery voltage is equal to or lower than the stop threshold" may be interpreted as "when the remaining power of the battery 41 is less than the stop threshold." In other words, the remaining power and the output voltage may be interpreted interchangeably. The stop threshold may be a parameter indicating the remaining power at which a transition to a power saving state should be made. The stop threshold may be a parameter that expresses the remaining power as a percentage, such as 10%, 20%, or 25%.

[0114] The main controller 10 may estimate the remaining power based on the battery voltage. The method for estimating the remaining power is not limited to the OCV (Open Circuit Voltage) method. The main controller 10 may estimate the remaining power using a current integration method (Coulomb counting method) or an impedance tracking method. The main controller 10 may estimate the remaining power using any estimation method. The main controller 10 may set the operation mode of the portable device 1 to a power saving state when the estimated SOC value falls below a predetermined value.

[0115] Some or all of the functions of the main controller 10 may be provided in the first wireless module 6. The functional layout within the portable device 1 may be changed as appropriate. In other embodiments, the portable device 1 may be provided with one or more push switches. The method of data communication between the portable device 1 and the in-vehicle system 2 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.

[0116] Ranging communication is not limited to UWB-IR, and may be performed using Bluetooth LE, Wi-Fi, etc. 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 on multiple channels. CS ranging is sometimes called High Accuracy Distance Measurement (HADM) or phase difference ranging.

[0117] The present disclosure is applicable not only to vehicles but also to electronic key systems for buildings and facilities. The portable device 1 and the system may be a system for controlling the locking state of doors in buildings or lockers. The charging method for the portable device 1 is not limited to wireless charging, and it may be charged using a cable. The portable device 1 may have a connector for inserting a charging cable.

[0118] <Additional remarks (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.

[0119] [Technical thought 1] A portable device that functions as a wireless door key and operates on a secondary battery (41), a communication unit (6) for wirelessly communicating with a system for controlling the locking state of the door; a control circuit (10) that controls the communication unit, The control circuit a voltage monitoring terminal (17) to which a signal indicating the output voltage of the secondary battery is input, determining whether the output voltage is greater than a predetermined threshold value based on a signal input to the voltage monitoring terminal; When the output voltage of the secondary battery is greater than the threshold value, the portable device is set to an ON state in which it can operate as the wireless key, and when the output voltage of the secondary battery is equal to or less than the threshold value, the portable device is set to an OFF state in which it does not function as the wireless key.

[0120] [Technical thought 2] The on state is a state in which an operating voltage is input to the control circuit, The portable device described in Technical Idea 1, wherein the off state is a state in which the operating voltage is not input to the control circuit.

[0121] [Technical thought 3] a power supply circuit (42) that generates an operating voltage for operating the control circuit from the output voltage of the secondary battery and outputs the operating voltage to the control circuit; The control circuit If it is determined that the output voltage of the secondary battery is greater than the threshold value, the power supply circuit continues to operate, When it is detected that the output voltage of the secondary battery is equal to or lower than the threshold, the power supply circuit is stopped. The state in which the portable device is operable as the wireless key is a state in which the power supply circuit is operating, The portable device according to Technical Idea 1, wherein the state in which the portable device does not function as the wireless key is a state in which the power supply circuit is stopped.

[0122] [Technical thought 4] a power supply circuit (42) that generates a voltage for operating the control circuit from the output voltage of the secondary battery and supplies power to the control circuit; The power supply circuit includes an enable terminal (423); the control circuit includes a control terminal (16) for outputting a signal for controlling the operation of the power supply circuit; the enable terminal is connected to the control terminal; The control circuit When it is determined that the output voltage of the secondary battery is greater than the threshold value, a high level signal is output from the control terminal to operate the power supply circuit; The portable device described in Technical Idea 1 is configured to stop the power supply circuit by outputting a low-level signal from the control terminal when it detects that the output voltage of the secondary battery is below the threshold.

[0123] [Technical thought 5] The portable device according to Technical Idea 4, wherein the enable terminal is connected to the control terminal via a resistance element (44) of 100 kΩ or more.

[0124] [Technical Thought 6] The portable device according to Technical Idea 4 or 5, wherein the enable terminal is connected to ground via a resistive element (43).

[0125] [Technical Thought 7] a power receiving unit (5) that receives power from an external device and charges the secondary battery; the power receiving unit includes a temporary supply circuit (54) that generates the operating voltage based on the power received from the external device and outputs the operating voltage to the control circuit; The portable device described in any one of Technical Ideas 4 to 6, wherein the control circuit is configured to start up when the operating voltage is input from the temporary supply circuit and begin outputting a high-level signal from the control terminal when the power is off due to the power supply circuit being stopped.

[0126] [Technical Thought 8] the power supply circuit includes an operating voltage output terminal (422) for outputting the operating voltage; The portable device according to any one of Technical Ideas 4 to 7, wherein the operating voltage output terminal is electrically connected to the control terminal (16) via a resistive element (45).

[0127] [Technical Thought 9] Further provided with a vibration sensor (3) for detecting vibration. The control circuit includes a storage unit (13) for storing data indicating whether the product is shipped from the factory or not. The control circuit referring to the storage unit based on the vibration detected by the vibration sensor; A portable device described in any one of technical ideas 1 to 8, which is configured to set the portable device to the off state based on the fact that data indicating that the portable device is shipped from the factory is stored in the memory unit.

[0128] [Technical Thought 10] the communication unit is configured to be able to receive a command signal from the system instructing a change of the threshold value, The portable device according to any one of Technical Ideas 1 to 9, wherein the control circuit is configured to change the set value of the threshold value based on receiving the command signal.

[0129] [Technical Thought 11] A portable device described in any one of technical ideas 1 to 10, wherein the control circuit is configured to change the threshold setting value depending on how often the portable device is used by the user.

[0130] [Technical Thought 12] A portable device that functions as a wireless door key and operates on a secondary battery (41), a communication unit (6) for wirelessly communicating with a system for controlling the locking state of the door; a control circuit (10) for controlling the communication unit; a power supply circuit (42) that generates an operating voltage for operating the control circuit from the output voltage of the secondary battery and outputs the operating voltage to the control circuit, The control circuit a voltage monitoring terminal (17) that is an input terminal to which a signal indicating the output voltage of the secondary battery is input, determining whether the output voltage is greater than a predetermined threshold value based on a signal input to the voltage monitoring terminal; If it is determined that the output voltage of the secondary battery is greater than the threshold value, the power supply circuit continues to operate, The portable device is configured to stop the power supply circuit when it is detected that the output voltage of the secondary battery is equal to or lower than the threshold value.

[0131] [Technical Thought 13] a power receiving unit (5) that receives power from an external device and charges the secondary battery; the power receiving unit is configured to be able to input the operating voltage to the control circuit, A portable device described in any one of technical ideas 1 to 12, wherein when the power supply circuit is in a stopped state, the control circuit is configured to start up based on the operating voltage being input from the power receiving unit.

[0132] <Additional remarks> The various flowcharts shown in this disclosure are merely examples, and the number of steps constituting the flowcharts and the order of execution 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 used interchangeably. When a device acquires certain data, it also includes the device generating the data based on a signal input from another device / sensor.

[0133] The apparatus, system, and methods described herein may be implemented by a special-purpose computer comprising a processor programmed to execute one or more functions embodied in a computer program. The apparatus and methods described herein may be implemented using dedicated hardware logic circuits. The apparatus and methods 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 main controller 10 may be implemented as hardware. Some or all of the functions of the main controller 10 may be implemented using any of a system-on-chip (SoC), an integrated circuit (IC), and a field-programmable gate array (FPGA).

[0134] A 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. [Explanation of symbols]

[0135] 1 Portable device, 2 In-vehicle system, 3 Acceleration sensor (vibration sensor), 4 Power supply unit, 5 Power receiving unit, 6 First wireless module (communication unit), 10 Main controller (control circuit), 13 Storage (memory unit), 16 Control terminal (control terminal), 17 Voltage monitoring terminal, 41 Battery (secondary battery), 42 First regulator (power supply circuit), 43 First resistor (resistance element), 44 Second resistor (resistance element), 45 Third resistor (resistance element), 54 Second regulator (temporary supply circuit), 422 Voltage output terminal, 423 Enable terminal

Claims

1. A portable device that functions as a wireless door key and operates on a secondary battery (41), a communication unit (6) for wirelessly communicating with a system for controlling the locking state of the door; a control circuit (10) that controls the communication unit, The control circuit a voltage monitoring terminal (17) that is an input terminal to which a signal indicating the output voltage of the secondary battery is input, determining whether the output voltage is greater than a predetermined threshold value based on a signal input to the voltage monitoring terminal; When the output voltage of the secondary battery is greater than the threshold value, the portable device is set to an ON state in which it can operate as the wireless key, and when the output voltage of the secondary battery is equal to or less than the threshold value, the portable device is set to an OFF state in which it does not function as the wireless key.

2. The on state is a state in which an operating voltage is input to the control circuit, The portable device according to claim 1 , wherein the off state is a state in which the operating voltage is not input to the control circuit.

3. a power supply circuit (42) that generates an operating voltage for the control circuit from the output voltage of the secondary battery and outputs the operating voltage to the control circuit; The control circuit If it is determined that the output voltage of the secondary battery is greater than the threshold value, the power supply circuit continues to operate, When it is detected that the output voltage of the secondary battery is equal to or lower than the threshold, the power supply circuit is stopped. The state in which the portable device is operable as the wireless key is a state in which the power supply circuit is operating, The portable device according to claim 1 , wherein the state in which the portable device does not function as the wireless key is a state in which the power supply circuit is stopped.

4. a power supply circuit (42) that generates an operating voltage for the control circuit from the output voltage of the secondary battery and supplies power to the control circuit; The power supply circuit has an enable terminal (423); the control circuit has a control terminal (16) for outputting a signal for controlling the operation of the power supply circuit; the enable terminal is connected to the control terminal; The control circuit When it is determined that the output voltage of the secondary battery is greater than the threshold value, a high level signal is output from the control terminal to the enable terminal to operate the power supply circuit; 2. The portable device according to claim 1, wherein when it is detected that the output voltage of the secondary battery is equal to or lower than the threshold, the power supply circuit is stopped by outputting a low-level signal from the control terminal to the enable terminal.

5. 5. The portable device according to claim 4, wherein the enable terminal is connected to the control terminal via a resistor element (44) having a resistance of 100 kΩ or more.

6. 5. The portable device according to claim 4, wherein the enable terminal is connected to ground via a resistive element (43).

7. a power receiving unit (5) that receives power from an external device and charges the secondary battery; the power receiving unit includes a temporary supply circuit (54) that generates the operating voltage based on the power received from the external device and outputs the operating voltage to the control circuit; The control circuit 5. The portable device according to claim 4, wherein when the power supply circuit is in a power-off state due to a shutdown of the power supply circuit, the portable device is configured to start up based on the input of the operating voltage from the temporary supply circuit and to start outputting a high-level signal from the control terminal.

8. the power supply circuit includes an operating voltage output terminal (422) for outputting the operating voltage; 5. The portable device according to claim 4, wherein the operating voltage output terminal is electrically connected to the control terminal (16) through a resistive element (45).

9. Further provided is a vibration sensor (3) for detecting vibration. The control circuit includes a storage unit (13) for storing data indicating whether the product is shipped from the factory or not. The control circuit referring to the storage unit based on the vibration detected by the vibration sensor; 5. The portable device according to claim 1, wherein the portable device is configured to set the off state based on the data stored in the storage unit indicating that the portable device is at the time of shipment from the factory.

10. the communication unit is configured to be able to receive a command signal from the system instructing a change of the threshold value, 5. The portable device according to claim 1, wherein the control circuit is configured to change the set value of the threshold value based on the reception of the command signal.

11. 5. The portable device according to claim 1, wherein the control circuit is configured to change the set value of the threshold value depending on how often the portable device is used by a user.

Images