JP7382822B2 - RFID tag - Google Patents

Description

The present disclosure relates to an RFID (radio frequency identifier) tag that includes a first functional section, a second functional section, and a power generation section that operate using electric power.

Patent Document 1 shows an RFID tag that includes a display and a secondary battery. In this RFID tag, a charging/discharging circuit that charges and discharges the secondary battery has two capacitors.

Japanese Patent Application Publication No. 2004-303174

In an RFID tag that includes a functional section and a power generation section, as the number of functional sections increases and the total power consumption increases, it becomes impossible to obtain the desired operation of each functional section when a power shortage occurs. On the other hand, if a large-capacity power storage unit that stores generated power is added to compensate for power shortages, it will take a long time from the time when the RFID tag becomes capable of generating power until the power is stored in the power storage unit. In this case, a problem arises in that it becomes difficult to comply with a request for a functional unit that is required to start up quickly.

An object of the present disclosure is to provide an RFID tag with a charging configuration that can easily realize suitable power supply to each functional unit.

The RFID tag of the present disclosure includes:
RFID IC and
A power generation section that receives energy from the environment and generates electricity,
A first power storage unit and a second power storage unit that store electric power;
A first functional unit and a second functional unit that operate using electric power;
a charging control unit that can separately control charging of the first power storage unit and charging of the second power storage unit using the power generated by the power generation unit;
Equipped with
The first functional unit operates with the power of the first power storage unit, and the second functional unit operates with the power of the second power storage unit,
The first functional section includes the RFID IC and a first control section ,
The second functional unit includes a light emitter that can be lit in response to a request from a reader/writer,
The first control unit writes information on whether or not the light emitter can operate based on the amount of charge in the second power storage unit to the RFID IC.

According to the present disclosure, there is an effect that power can be appropriately supplied to the first functional section and the second functional section.

FIG. 1 is an exploded perspective view showing an RFID tag according to Embodiment 1 of the present disclosure. 1 is a diagram showing a circuit configuration of an RFID tag according to Embodiment 1. FIG. 3 is a circuit diagram showing details of a configuration related to charging control in the circuit configuration of FIG. 2. FIG. 5 is a timing chart showing an example of charging control. 3 is a flowchart illustrating an example of a response processing procedure executed by a control unit. FIG. 3 is a circuit diagram showing a configuration related to charging control in an RFID tag according to Embodiment 2 of the present disclosure. 7 is a timing chart illustrating an example of charging control in Embodiment 2. FIG. 3 is a diagram showing a circuit configuration of an RFID tag according to Embodiment 3. FIG. 12 is a flowchart illustrating an example of power supply voltage monitoring processing according to the third embodiment.

Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is an exploded perspective view showing an RFID tag according to a first embodiment. FIG. 2 is a diagram showing the circuit configuration of the RFID tag according to the first embodiment.

As shown in FIG. 1, the RFID tag 1 of the first embodiment includes a housing 10, a circuit board 20, power generation units 31 and 32, a display 33, a light emitter 29, and a lid 40. The housing 10 has a concave shape with one side open, and can accommodate the circuit board 20 and the display 33 stacked on top of each other, and the two power generation units 31 and 32 arranged side by side on the left and right sides of the display 33. The display 33 is connected to the circuit board 20 via sheet wiring 33h. The circuit board 20 includes a plurality of integrated circuits, a plurality of electric elements, and an antenna conductor for RFID communication. The power generation units 31 and 32 are photovoltaic panels that generate power by receiving light from the outside, but may also be configured to generate power by absorbing various environmental energies such as heat or vibration.

As shown in FIG. 2, the RFID tag 1 further includes a first power storage section 21 and a second power storage section 22 that store the power generated by the power generation sections 31 and 32, and a first power storage section 21 and a second power storage section 22. A charging control unit 23 that controls charging, power supply ICs (Integrated Circuits) 24 and 25 that generate power supply voltages for each part using charged power, an RFID IC 26, and controls the display 33 and light emitter 29. and a first comparator 28 for detecting the state of charge of the second power storage unit 22. The first power storage unit 21 , the second power storage unit 22 , the charging control unit 23 , the power supply ICs 24 and 25 , the RFID IC 26 , the first comparator 28 , the light emitter 29 , and the control unit 27 are mounted on the circuit board 20 . The first comparator 28 corresponds to an example of a detection unit according to the present disclosure.

The display device 33 is, for example, a liquid crystal display device, and displays information on a screen. The displayed content is not particularly limited, but includes, for example, management information of articles managed by the RFID tag 1. Display on the display 33 is required to be performed at all times while the RFID tag 1 is in operation, and the operation period of the display 33 is long. The display device 33 is a reflective liquid crystal display device that performs display using external light, and has low power consumption.

The light emitter 29 is, for example, a light emitting diode, and performs lighting display. The use of the lighting display is not particularly limited, but for example, when extracting only a specific one from a plurality of RFID tags 1, it may be used to turn on, blink, or extinguish only the light emitting device 29 of the specific RFID tag 1. It's okay. The light emitter 29 may be configured to be driven in response to a temporary request, and its operating period is shorter than the operating period of the display 33. The power consumption of the light emitter 29 is larger than that of the display 33. The power consumption to be compared may be the power consumption during standard driving.

The RFID IC 26 uses radio waves in the UHF (Ultra High Frequency) band, for example, to perform wireless communication with the reader/writer via an antenna conductor. The RFID IC 26 has a storage section that can read and write information from a reader/writer, and a storage section that stores individual identification information. The reader/writer can read the management information of the article managed by the RFID tag 1 from the storage section and write the updated management information to the storage section. Further, the reader/writer may be configured to be able to write information indicating the display contents of the display 33 and a command for driving the light emitter 29 into the storage section.

The control unit 27 communicates with the RFID IC 26 and can read and write information in the storage unit of the RFID IC 26 . Further, the control unit 27 controls the display of the display 33 and controls the drive of the light emitter 29.

The first power storage unit 21 and the second power storage unit 22 can store electric power generated by the power generation units 31 and 32. The first power storage unit 21 and the second power storage unit 22 may be capacitors whose voltage changes depending on the amount of charge. The storage capacity of the first power storage unit 21 (for example, a capacitance of 50 μF to 500 μF) is smaller than the storage capacity of the second power storage unit 22 (for example, a capacitance of 0.7 mF to 2 mF).

The power supply IC 24 generates a power supply voltage from the power stored in the first power storage unit 21 and supplies the generated power supply voltage to the control unit 27, the RFID IC 26, and the display 33. Power supply IC 25 generates a power supply voltage from the power stored in second power storage unit 22 and supplies the generated power supply voltage to light emitter 29 . The number of power supply voltages generated may be one type or multiple types.

First comparator 28 compares the voltage of second power storage unit 22 with reference voltage Vref, and sends a signal indicating whether or not light emitter 29 can be driven to control unit 27 . The reference voltage Vref may be set to the minimum voltage that can drive the light emitter 29.

The charging control unit 23 operates with the power generated by the power generation units 31 and 32, and sends the generated power to the first power storage unit 21 and the second power storage unit 22. Charging control unit 23 prioritizes charging of first power storage unit 21 over charging of second power storage unit 22, depending on the charging status of first power storage unit 21 and second power storage unit 22. For example, when both are in a charging state that requires charging, the charging control unit 23 sets the ratio of the charging current of the first power storage unit 21 and the charging current of the second power storage unit 22 to 1:0, etc. The portion 21 is made larger. The above-mentioned ratio may be a ratio such as 5:1 at which a small amount of charging is performed in the second power storage unit 22. In addition, the charging control unit 23 charges the second power storage unit 22 during a period when the first power storage unit 21 reaches full charge and stops charging, and the power of the first power storage unit 21 is consumed and charging is restarted. When the second power storage unit 22 is stopped charging, or the amount of charge is reduced compared to the charging stop period of the first power storage unit 21.

Next, a specific example of charging control that prioritizes charging of the first power storage unit 21 over charging of the second power storage unit 22 will be described. However, the following charging control is only an example, and the charging control by the charging control section 23 is not limited to the following example.

FIG. 3 is a circuit diagram showing details of a configuration related to charging control in the circuit configuration of FIG. 2. In FIG.

The charging control unit 23 includes switches SW1 to SW4 that switch between the power input line L1 or the power output lines L2 and L3 and the first power storage unit 21 and the second power storage unit 22, and a switch control unit 23A that switches the switches SW1 to SW4. Equipped with. The power input line L1 transmits the power generated by the power generation units 31 and 32. Power output line L2 transmits power from first power storage unit 21 to power supply IC 24. The power transmitted to the power output line L2 is sent to the control unit 27, the RFID IC 26, and the display 33 via the power supply IC 24. Power output line L3 transmits power from second power storage unit 22 to power supply IC 25. The power transmitted to the power output line L3 is sent to the light emitter 29 via the power supply IC25. Switches SW1 and SW3 connect or disconnect power input line L1 and first power storage unit 21, and power input line L1 and second power storage unit 22, respectively. Switch SW2 connects or disconnects first power storage unit 21 and power output line L2. Switch SW4 connects or disconnects second power storage unit 22 and power output line L3.

Switch control unit 23A receives a signal indicating the charging state of first power storage unit 21 and second power storage unit 22, and controls switches SW1 to SW2 based on this signal. The signal indicating the charging state may be the voltage of the first power storage unit 21 and the voltage of the second power storage unit 22, but is not limited to the voltage as long as the charging rate is known. Hereinafter, the voltage of the first power storage unit 21 will be referred to as a first power storage voltage, and the voltage of the second power storage unit 22 will be referred to as a second power storage voltage. When control based on charging rate is adopted instead of control based on voltage, the voltages of the first storage voltage and the second storage voltage may be read as the charging rate.

FIG. 4 is a timing chart showing an example of charging control.

The switch control unit 23A turns on the switch SW2 when the first storage voltage is equal to or higher than the power supply start voltage V0, and starts discharging from the first storage unit 21. After turning on switch SW2, switch control unit 23A turns off switch SW2 to stop discharging of first power storage unit 21 when the first storage voltage falls below a discharge end voltage that is lower than power supply start voltage V0. good. Switch control unit 23A turns on switch SW1 to turn on switch SW1 when the first storage voltage is lower than charging restart voltage V1 and until the first storage voltage reaches charging end voltage V2 from lower than charging restart voltage V1. Charge 21. Switch control unit 23A turns off switch SW1 to stop charging of first power storage unit 21 from when the first power storage voltage reaches charge end voltage V2 until it decreases to charge restart voltage V1. Charging end voltage V2 is a voltage indicating full charge of first power storage unit 21, and charging restart voltage V1 is set between power supply start voltage V0 and charging end voltage V2. The charging end voltage V2 corresponds to an example of the first voltage of the present disclosure. The charging restart voltage V1 corresponds to an example of the second voltage of the present disclosure.

According to the control of the switches SW1 and SW2, when the power generation units 31 and 32 are generating power at a specified amount or more, the first storage voltage immediately exceeds the power supply start voltage V0, and the first storage unit 21 Discharge begins. Therefore, power is quickly supplied to the control unit 27, the RFID IC 26, and the display 33. Thereafter, the first storage voltage increases, and when the first storage unit 21 reaches full charge, charging to the first storage unit 21 is repeatedly stopped and restarted, and the first storage voltage increases to the charging end voltage V2 and charging The voltage transitions between the restart voltage V1 and the restart voltage V1.

Similarly, the switch control unit 23A turns on the switch SW4 when the second storage voltage is equal to or higher than the power supply start voltage Vb0, thereby enabling the second storage unit 22 to be discharged. Although not shown in FIG. 4, the switch control unit 23A turns off the switch SW4 to stop discharging the second power storage unit 22 when the second storage voltage falls below the minimum discharge voltage that is lower than the power supply start voltage Vb0. Good too. Further, switch control unit 23A may turn off switch SW4 to stop charging second power storage unit 22 when the second storage voltage reaches a charging end voltage higher than power supply start voltage Vb0. The charging end voltage corresponds to the voltage when the second power storage unit 22 is fully charged. The power supply start voltage Vb0 may be set to a charge end voltage corresponding to a full charge voltage.

Switch control unit 23A turns on switch SW3 to turn on switch SW3 while charging of first power storage unit 21 is stopped (corresponding to the first period of the present disclosure) when the second power storage voltage is equal to or lower than the charging end voltage. Charge. In addition, even if the second storage voltage is lower than the charge end voltage, the switch control unit 23A turns off the switch SW3 and charges the second storage unit 21 while the first storage unit 21 is being charged (resuming charging). Do not charge the battery.

According to the control of the switches SW3 and SW4, when the power generation units 31 and 32 are generating power at a specified amount or more, charging of the first power storage unit 21 is stopped after the first power storage unit 21 is fully charged. While the stop and restart are repeated, the second power storage unit 22 is charged using the generated power during the period when the charging of the first power storage unit 21 is stopped. Then, as charging progresses and the second storage voltage exceeds the power supply start voltage Vb0, a large amount of power is stored in the second storage unit 22. Although the charging time of the second power storage unit 22 becomes longer due to the low priority of charging, the light emitter 29 can be driven by storing a large amount of electric power. Furthermore, since the power output line L3 of the second power storage unit 22 and the power output line L2 of the first power storage unit 21 are separated, even if the light emitter 29 consumes a large amount of power and the power supply voltage drops, The voltage drop does not affect the first power storage unit 21, and the operation of the control unit 27 and the display 33 does not stop.

<Operation example of RFID tag>
Management information of managed articles is written in the storage section of the RFID IC 26. In this state, when the RFID tag 1 is irradiated with environmental light, the first storage voltage quickly rises to the power supply start voltage V0 due to power generation by the power generation units 31 and 32, and the control unit 27. The RFID IC 26 and the display 33 are activated immediately. Prompt startup is achieved because the first power storage unit 21 has a small power storage capacity and the charging control unit 23 preferentially charges the first power storage unit 21 .

After startup, the control unit 27 reads management information from the RFID IC 26 and controls the display 33 to display the management information. The worker can check the management information regarding the article associated with the RFID tag 1 from the screen display of the display 33. When updating the management information of an article through a predetermined process, the worker writes new management information into the storage section of the RFID IC 26 through wireless communication using a reader/writer. After the management information has been rewritten, the control unit 27 displays the new management information on the display 33.

When there are multiple items and multiple RFID tags 1 associated with the multiple items, and a request to extract (pick up) one of the items occurs, a worker uses a reader/writer to issue an extraction request. A response request is made to a certain RFID tag 1. As a first example, a response request by a worker is realized by a reader/writer writing identification information of the RFID tag 1 requesting a response and a command code for the response request into a plurality of RFID tags 1. A command code for a response request is written in the storage section of the RFID IC 26, and when the control section 27 reads it, the control section 27 of the RFID tag 1 verifies the identification information. If the identification information is the same as the identification information stored in the RFID IC, the control unit 27 executes a response process in response to the response request, and if it is not the same, the control unit 27 ignores the response request. As a second example, the above response request by the worker is realized by the reader/writer reading identification information from a plurality of RFID tags 1 and writing a response request command code to the RFID tag 1 having the target identification information. It's okay. The control unit 27 of the target RFID tag 1 reads the response request from the storage unit of the RFID IC 26 and executes response processing in response to the response request.

Since the second power storage unit 22 is stored with a lower priority than the first power storage unit 21 and has a large power storage capacity, a relatively long time has passed after the RFID tag 1 is placed in an environment where it can generate electricity. After that, discharge from the second power storage unit 22 becomes possible. However, the light emitting device 29 is rarely requested to be driven within a short time after it becomes capable of generating electricity, and is required to be driven temporarily and for a short period of time, so in many cases, when a response request is made, the second Electric power is stored in the power storage unit 22.

FIG. 5 is a flowchart illustrating an example of response processing executed by the control unit. When the control unit 27 starts the response process, it first determines whether or not the light emitter 29 can be driven based on the output of the first comparator 28 (step S1). As a result of the determination, if the light emitter 29 can be driven, the light emitter 29 is driven (step S2). The worker can confirm that the light emitting device 29 of the RFID tag 1 is lit and easily select a specific one from among the plurality of RFID tags 1.

On the other hand, if a request is made to drive the light emitter 29 when the second power storage unit 22 is not fully charged, the light emitter 29 cannot be driven. In this case, the determination result in step S1 is NO. In this case, the control unit 27 writes information indicating that the light emitter 29 is inoperable in the storage unit of the RFID IC 26 (step S3). The processing in step S3 corresponds to the processing operation of the first control unit according to the present disclosure. After receiving the response request, the reader/writer reads information from the plurality of RFID tags 1 and confirms whether information indicating that the light emitter 29 is inoperable is not written in the storage section. If there is information indicating that the light emitter 29 is inoperable, the reader/writer displays a message in the notification section (display notification section, audio notification section, etc.) of the reader/writer that says "The RFID tag 1 requested for extraction exists. "Cannot respond due to lack of power" is output. Based on this notification, after a while, when the amount of charge in the second power storage unit 22 has increased, the worker sends a response request again from the reader/writer to activate the light emitting device 29 of the specific RFID tag 1. can be lit. On the other hand, if there is no RFID tag 1 with the light emitter 29 lit, and in addition, the above notification indicating the presence is not sent to the notification section of the reader/writer, the worker can check whether the RFID tag 1 to be extracted is on the spot. I can recognize that it doesn't exist.

Note that the process of extracting a specific RFID tag 1 may be a process in which only the specific RFID tag 1 does not drive the light emitter 29, and all remaining RFID tags 1 drive the light emitter 29. The worker can identify the RFID tag 1 that is not emitting light. In this case, the response request from the worker need only be sent to a device other than the specific RFID tag 1.

As described above, the RFID tag 1 of the first embodiment includes the first power storage section 21 and the second power storage section 22, and the control section 27, the RFID IC 26, and the display 33 (first functional section) It is driven by the power of the power storage unit 21 , and the light emitter 29 (second functional unit) is driven by the power of the second power storage unit 22 . Furthermore, the RFID tag 1 includes a charging control section 23 that can separately control charging of the first power storage section 21 and charging of the second power storage section 22. Therefore, the operating conditions (quick start-up, etc.) and characteristics (low power consumption, etc.) required of the first functional section, and the operating conditions (temporarily short-time operation, etc.) required of the second functional section. The characteristics (storage capacity, etc.) and charging conditions of the first power storage unit 21 and the second power storage unit 22 can be varied depending on the characteristics (such as high power consumption). Therefore, the first power storage unit 21 and the second power storage unit 22 can be charged and discharged so that power can be supplied to the first function unit and the second function unit respectively, and the desired power of the first function unit can be charged and discharged. It becomes easy to realize both the operation and the desired operation of the second functional section.

Furthermore, according to the RFID tag 1 of the first embodiment, the power storage capacity of the first power storage unit 21 is smaller than the power storage capacity of the second power storage unit 22. Therefore, the charging time of the first power storage unit 21 can be shortened. Furthermore, the operating period of the light emitter 29 (second functional section) is shorter than the operating period of the control section 27, RFID IC 26, and display 33 (first functional section). Therefore, by quickly charging the first power storage unit 21, the first functional unit can quickly operate, and the first functional unit can operate for a long period of time.

Furthermore, according to the RFID tag 1 of the first embodiment, the power consumption of the control unit 27, the RFID IC 26, and the display unit 33 (first functional unit) is smaller than the power consumption of the light emitter 29 (second functional unit). . Therefore, the second power storage unit 22 with a large power storage capacity and the first power storage unit 21 with a small power storage capacity can supply power suitable for each of the first functional unit and the second functional unit that have different power consumption. .

Furthermore, according to the RFID tag 1 of the first embodiment, the charging control unit 23 gives priority to charging the first power storage unit 21 over charging the second power storage unit 22. Therefore, the first power storage unit 21 can be charged to a voltage that can be quickly discharged in response to requests for prompt activation of the control unit 27, the RFID IC 26, and the display device 33 (first functional unit).

Furthermore, according to the RFID tag 1 of the first embodiment, the charging control unit 23 stops charging the first power storage unit 21 when the first power storage voltage reaches the charging end voltage V2, and the charging control unit 23 stops charging the first power storage unit 21 when the first power storage voltage reaches the charging end voltage V2. When the voltage drops below V1, charging of the first power storage unit 21 is restarted. In addition, the charging control unit 23 charges the second power storage unit 22 during the period when charging to the first power storage unit 21 is stopped, and stops charging the second power storage unit 22 when charging to the first power storage unit 21 is resumed. Stop or reduce. According to such charging control, if the first functional unit is highly required to continue stable operation, and the second functional unit is required to operate infrequently and cannot be operated, it is possible to deal with the case. In addition, it is possible to realize a power supply suitable for these demands. More specifically, when the display 33 that displays on the screen is used as the first functional part and the light emitting device 29 that can be lit is used as the second functional part, more suitable power supply can be achieved.

Furthermore, according to the RFID tag 1 of the first embodiment, during response processing, the control unit 27 writes information on whether the light emitter 29 can operate or not into the storage unit of the RFID IC 26 based on the output of the first comparator 28. . Therefore, the worker can use the reader/writer to check whether the RFID tag 1 can drive the light emitter 29 or not. Note that the information on whether or not the light emitter 29 is operable is not limited to the time of response processing, and the control unit 27 writes it to the storage unit of the RFID IC 26 at various timings or in various cycles, so that the reader/writer can emit light at various timings. It may be possible to check whether or not.
(Embodiment 2)
FIG. 6 is a circuit diagram showing a configuration related to charging control in an RFID tag according to Embodiment 2 of the present disclosure. FIG. 7 is a timing chart showing an example of charging control according to the second embodiment.

The RFID tag of the second embodiment is different from the first embodiment in the configurations of the second power storage unit 22 and the charging control unit 23, and the other configurations are the same as in the first embodiment. In the RFID tag of the second embodiment, the second power storage unit 22 that stores the driving power for the light emitter 29 includes a plurality of power storage units 22a to 22c. The capacitors 22a to 22c may be capacitors whose voltage changes depending on the amount of charge. The power storage capacity of the first power storage unit 21 is smaller than the power storage capacity of the second power storage unit 22, which is a total of power storage units 22a to 22c.

The charging control unit 23 of the second embodiment includes switches SW3a to SW3c and SW4a to SW4c that can individually switch charging and discharging of the plurality of capacitors 22a to 22c. The switches SW3a to SW3c connect or disconnect the power input line L1 and the plurality of capacitors 22a to 22c, respectively. The switches SW4a to SW4c connect or disconnect the power output line L3 and the plurality of capacitors 22a to 22c, respectively.

23 A of switch control parts charge the 1st electrical storage part 21 preferentially rather than the 2nd electrical storage part 22 similarly to Embodiment 1. Furthermore, in the second embodiment, the charging priorities of the plurality of capacitors 22a to 22c are different, and the switch control unit 23A charges the capacitors 22a to 22c in priority order. For example, as shown in FIG. 7, similarly to Embodiment 1, after the first power storage unit 21 reaches full charge, charging of the first power storage unit 21 is stopped and resumed (turning on and off of switch SW1) repeatedly. It will be done. Then, during the charging stop period of first power storage unit 21 (the OFF period of switch SW1 in FIG. 7), second power storage unit 22 is charged (switches SW3a to SW3c are turned on). At this time, first, the power storage device 22a having the first priority is charged (switch SW3a is turned on). Then, when the charging voltage of the capacitor 22a exceeds the power supply start voltage Vc0, the switch SW4a is turned on and power can be output from the capacitor 22a to the light emitter 29. Thereafter, during the charging stop period of the first power storage unit 21, the power storage device 22b having the second priority is charged (switch SW3b is turned on). Similarly, when the charging voltage of the capacitors 22a and 22b with the first and second priorities exceeds the power supply start voltage Vc0, the switch SW4b is turned on, the capacitors 22a and 22b are connected in parallel, and the capacitors 22a and 22b are connected in parallel. Electric power can now be output to the light emitter 29. Furthermore, after that, during the charging stop period of the first power storage unit 21, the power storage device 22c with the third priority is charged (switch SW3c is turned on), and when the charging voltage exceeds the power supply start voltage Vc0, the switch SW4c is turned on. The capacitors 22a to 22c are connected in parallel. Electric power can then be output from the capacitors 22a to 22c to the light emitter 29.

When the switch SW4b is turned on, the capacitors 22a and 22b are connected in parallel and have the same voltage, and thereafter, the charge of the capacitors 22a and 22b may be integrally controlled until the discharge end voltage is reached. Further, when the switches SW4b and SW4c are turned on, the capacitors 22a to 22c are connected in parallel to have the same voltage, and thereafter, the charge of the capacitors 22a to 22c may be integrally controlled until the discharge end voltage is reached. and. When the voltage of the two capacitors 22a, 22b or the three capacitors 22a to 22c drops below the minimum discharge voltage due to discharge and the switches SW4a to SW4c are turned off, the above-described individual charging control may be switched again. .

If the second power storage unit 22 has more power storage units, such as four or more, a lower priority is assigned to the fourth and subsequent power storage units, and charging control is performed in the order of priority in the same manner as described above.

As described above, according to the RFID tag of the second embodiment, the second power storage unit 22 has a plurality of power storage units 22a to 22c, and the charging control unit 23 can individually control charging of the plurality of power storage units 22a to 22c. . Therefore, even if the total storage capacity of the second power storage unit 22 is large, the power storage capacity of the individual power storage units 22a to 22c can be reduced, so that by charging the individual power storage units 22a to 22c in order, for example, the second power storage unit 22 can be quickly brought to a dischargeable voltage. Then, it becomes possible to quickly drive the light emitter 29 (second functional section). For example, if the high-priority condenser 22a reaches a dischargeable voltage, the light emitter 29 can be driven for a short time, and the worker can extract the lit RFID tag 1. Further, when the plurality of capacitors 22a to 22c reach a dischargeable voltage, the light emitter 29 can be driven for a specified time, and the worker can extract the lit RFID tag 1 with plenty of time to spare.

(Embodiment 3)
FIG. 8 is a diagram showing a circuit configuration of an RFID tag according to the third embodiment. FIG. 9 is a flowchart illustrating an example of power supply voltage monitoring processing executed by the control unit. In the RFID tag 1B of the third embodiment, when there is a remaining charge in the second power storage unit 22 and the remaining charge in the first power storage unit 21 decreases, the power of the second power storage unit 22 is transferred to the first power storage unit 21 or A function that enables power supply to the power IC 24 is added. Other components are the same as those in the first embodiment or the second embodiment. Next, a specific configuration example of this additional function will be described with reference to FIG. 8, but the configuration to which this function is added is not limited to the example of FIG. 8.

The RFID tag 1B of the third embodiment includes a switch SW11 that connects or disconnects the first power storage unit 21 and the second power storage unit 22, and a second switch SW11 that connects or disconnects the first power storage unit 21 and the second power storage unit 22. and a comparator 28B. A diode D1 that prevents current from flowing backward from the first power storage unit 21 to the second power storage unit 22 may be connected in series to the switch SW11. A control line of the switch SW11 is connected to the control section 27, and the switch SW11 can be switched under the control of the control section 27.

Second comparator 28B compares the voltage of first power storage unit 21 with threshold voltage Vref2, and outputs a signal indicating the comparison result to control unit 27. The threshold voltage Vref2 is a voltage indicating that the remaining charge of the first power storage unit 21 has become equal to or less than the threshold value, and is, for example, a voltage that is higher than the discharge stop voltage by an allowance, or a voltage that is higher than the discharge stop voltage, or a voltage that is higher than the discharge stop voltage, or a voltage that indicates that the remaining charge of the first power storage unit 21 is lower than the threshold value. The voltage may be set to be higher than the lower limit voltage for operation of the device 33 by an amount of margin.

When the control unit 27 is started by being supplied with power from the first power storage unit 21, it always executes the power supply voltage monitoring process shown in FIG. 9 during operation. The power supply voltage monitoring process corresponds to the processing operation of the second control unit according to the present disclosure. In the power supply voltage monitoring process, the control unit 27 determines the output of the second comparator 28B (step S11), and if the result of the determination is not a low level (a decrease in the remaining charge amount of the first power storage unit 21), the control unit 27 performs step S11. The process returns to S11 and the determination in step S11 is repeated.

On the other hand, if the result of the determination in step S11 is a low level, the control unit 27 determines the output of the first comparator 28 (step S12), and the result of the determination is a high level (remaining charge of the second power storage unit 22). If the amount is not present, the process returns to step S11 and the process from step S11 is repeated. If the result of the determination in step S12 is a high level, the control unit 27 turns on the switch SW11 for a predetermined period of time (step S13). When turned on for a predetermined period of time, the power stored in the second power storage unit 22 is sent to the first power storage unit 21, and power continues to be supplied from the first power storage unit 21 to the control unit 27, RFID IC 26, and display 33. can. After turning on the switch SW11 for a predetermined period of time in step S13, the control unit 27 turns off the switch SW11 and returns the process to step S11.

As described above, according to the RFID tag 1B of the third embodiment, the control unit 27 controls the power of the second power storage unit 22 to be transferred to the first power storage unit when the remaining charge level of the first power storage unit 21 becomes equal to or less than the threshold value. 21. After the RFID tag 1B is placed in a chargeable environment and both the first power storage unit 21 and the second power storage unit 22 are charged, the second power storage unit 22 is placed in a non-charging environment without consuming any power. It may happen. In such a case, when the power of the first power storage unit 21 is insufficient, the power of the second power storage unit 22 is used by the above-mentioned power supply voltage monitoring process to protect the control unit 27, the RFID IC 26, and the display. The device 33 can be driven for a longer period of time.

Each embodiment of the present disclosure has been described above. However, the present invention is not limited to the above embodiments. For example, in the embodiment described above, an example is shown in which the control unit 27, RFID IC 26, and display 33 are employed as the first functional unit, and the light emitter 29 is employed as the second functional unit. However, the first functional section or the second functional section may include various functional configurations such as various sensors such as a temperature sensor and an acceleration sensor, and an audio output device. Further, in the above embodiment, an example is shown in which capacitors are used as the first power storage unit and the second power storage unit, but a secondary battery may be applied. Other details shown in the embodiments can be changed as appropriate without departing from the spirit of the invention.

1, 1B RFID tag 20 Circuit board 21 First power storage unit 22 Second power storage unit 22a to 22c Power storage unit 23 Charging control unit 23A Switch control unit SW1 to SW4, SW3a to SW3c, SW4a to SW4c Switch L1 Power input line L2, L3 Power Output line 24, 25 Power IC
26 RFID IC (first functional part)
27 Control unit (first functional unit)
28 First comparator (detection section)
28B Second comparator SW11 Switch 29 Light emitter (second functional section)
31, 32 Power generation section 33 Display (first functional section)
V0, Vb0, Vc0 Power supply start voltage V1 Charging restart voltage V2 Charging end voltage

Claims (10)

RFID IC and
A power generation section that receives energy from the environment and generates electricity,
A first power storage unit and a second power storage unit that store electric power;
A first functional unit and a second functional unit that operate using electric power;
a charging control unit that can separately control charging of the first power storage unit and charging of the second power storage unit using the power generated by the power generation unit;
Equipped with
The first functional unit operates with the power of the first power storage unit, and the second functional unit operates with the power of the second power storage unit,
The first functional section includes the RFID IC and a first control section ,
The second functional unit includes a light emitter that can be lit in response to a request from a reader/writer,
The first control unit writes information on whether or not the light emitter can operate based on the amount of charge of the second power storage unit into the RFID IC.
RFID tag. The power storage capacity of the first power storage unit is smaller than the power storage capacity of the second power storage unit,
The operating period of the second functional section is shorter than the operating period of the first functional section.
RFID tag according to claim 1. power consumption of the second functional unit is greater than power consumption of the first functional unit;
RFID tag according to claim 2. The charging control section includes:
Prioritizing charging of the first power storage unit over charging of the second power storage unit,
The RFID tag according to any one of claims 1 to 3. The charging control section includes:
When the voltage of the first power storage unit reaches a first voltage, charging of the first power storage unit is stopped;
When the voltage of the first power storage unit drops to a second voltage lower than the first voltage, restarting charging of the first power storage unit,
charging the second power storage unit during a first period in which charging of the first power storage unit is stopped;
Stopping charging of the second power storage unit while resuming charging of the first power storage unit or reducing the amount of charge compared to the first period;
The RFID tag according to any one of claims 1 to 4. further comprising a detection unit that detects whether the amount of charge of the second power storage unit is below a threshold value,
The first control unit writes information on whether or not the light emitter is operable based on the detection result of the detection unit, in the RFID IC.
The RFID tag according to any one of claims 1 to 5. The second power storage unit includes a plurality of power storage units,
The charging control unit can individually control charging of the plurality of capacitors.
The RFID tag according to any one of claims 1 to 6. The first functional unit further includes a display that displays on a screen.
The RFID tag according to any one of claims 1 to 7. further comprising a second control unit that supplies the power of the second power storage unit to the first power storage unit or the first functional unit when the remaining charge of the first power storage unit is equal to or less than a threshold;
The RFID tag according to any one of claims 1 to 8. The charging control section includes:
When the voltage of the first power storage unit reaches a first voltage, charging of the first power storage unit is stopped;
When the voltage of the first power storage unit drops to a second voltage lower than the first voltage, restarting charging of the first power storage unit,
By charging the second power storage unit during a first period in which charging of the first power storage unit is stopped,
increasing the amount of charge of the second power storage unit from an amount at which the light emitting device does not operate to an amount at which the light emitting device operates;
The RFID tag according to any one of claims 1 to 4.

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