A passive tag hibernation method based on multiple energy storage units and a passive tag

Abstract

The application discloses a passive tag hibernation method based on multiple energy storage units and a passive tag. The method comprises the following steps: 1) establishing multiple charging energy storage units in the tag; 2) the passive tag is in a hibernation state, collects energy, converts external environment energy into electric energy, and charges the charging energy storage units; the passive tag preferentially charges the charging energy storage unit with the lowest voltage; 3) preferentially using the charging energy storage unit with the highest voltage to supply energy to a wake-up circuit; 4) the passive tag is in a working state: when the wake-up circuit receives a wake-up command or the passive tag is started at a fixed time, the passive tag supplies energy to an application load. The passive tag comprises a power management circuit, a wake-up circuit and an energy collection circuit, and multiple charging energy storage units; the charging ends of the charging energy storage units are respectively connected to the output ends of the energy collection circuit; and the discharging ends of the charging energy storage units are openably connected to the power supply end of the wake-up circuit or the power supply end of the application load.

Description

Technical Field

[0001] This invention belongs to the field of communication technology and relates to passive tag energy-saving technology for Internet of Things communication. Specifically, it is a passive tag (Passive RFID) sleep method based on multiple energy storage units and a passive tag. Background Technology

[0002] The development of the Internet of Things (IoT) requires integration with data algorithms, while the recent advancements in artificial intelligence have spurred massive data demands. Expanding the coverage area of ​​sensor nodes and increasing the depth of information collection are inevitable trends for future development. However, traditional IoT nodes are limited by power supplies, have limited battery life, and incur high manual maintenance costs, hindering widespread adoption. Therefore, academia and industry have begun extensive research on passive tags.

[0003] Passive tags typically operate at frequencies between 860-960MHz. Since they lack an internal power supply, their energy is generally harvested via radio frequency (RF) energy harvesting. Therefore, the communication distance is limited by the reader, typically less than 10 meters. A tag mainly consists of a tag antenna, a baseband control unit, and a storage unit. The storage unit stores information about the target item, while the tag antenna enables communication with the reader. When the RFID system is operational, the reader emits electromagnetic signals. When the tag receives these signals within the reader's operating area, it sends a portion of the energy to a rectifier circuit to obtain DC power, while a portion of the signal is demodulated by the RF front-end to obtain valid information.

[0004] As explained above, while passive tags can extract energy from their surroundings to power their continuous operation and necessary communication, the energy available in the environment is relatively weak and highly unstable. Therefore, ensuring extremely low standby power consumption for passive tags in the absence of power input is a crucial challenge.

[0005] Existing technologies often only control the tag to enter sleep mode through digital baseband, but ignore aspects that can be optimized, such as leakage current of energy storage components and the voltage of their own power supply. Summary of the Invention

[0006] To address the issue of reducing standby power consumption of passive tags, this invention proposes a passive tag sleep method based on multiple energy storage units. This method optimizes the power supply architecture of the passive tag to reduce its standby power consumption. The specific solution is as follows:

[0007] A passive tag hibernation method based on multiple energy storage units includes the following steps:

[0008] 1) Establish multiple charging energy storage units within the tag;

[0009] 2) The passive tag is in a dormant state, collecting energy and converting ambient energy into electrical energy to charge the energy storage unit;

[0010] Charging selection: The voltage of each charging energy storage unit is detected. If the detected voltage Vt of the t-th charging energy storage unit is the lowest, then the t-th charging energy storage unit with the lowest voltage is charged first. Charging is stopped when Vt reaches the maximum threshold, and the charging energy storage unit with the lowest voltage among the other charging energy storage units is switched to charge. That is, the charging energy storage unit with the lowest voltage is charged first.

[0011] 3) Selection of unit discharge for charging and energy storage to power the wake-up circuit:

[0012] After charging in step 2), Vt is at its highest, and the t-th charging energy storage unit powers the wake-up circuit of the passive tag; until Vt is lower than the maximum voltage in the charging energy storage unit, the charging energy storage unit corresponding to the maximum voltage powers the wake-up circuit of the passive tag; that is, the charging energy storage unit with the highest voltage is preferentially used to power the wake-up circuit of the passive tag.

[0013] 4) When the passive tag is in working condition, it provides power selection for the application load:

[0014] When the wake-up circuit of the passive tag receives a wake-up command, or when the passive tag starts on a timer, the passive tag powers the application load.

[0015] Furthermore, the multiple charging energy storage units are divided into a first type of charging energy storage unit that is isolated from each other and supplies power to the wake-up circuit, and a second type of charging energy storage unit that supplies power to the application load; each type of charging energy storage unit has one or more identical charging energy storage sub-units.

[0016] A. For the first type of rechargeable energy storage unit: when the charging voltage is lower than its detection voltage, disconnect it from the charging circuit;

[0017] In step 2), the charging energy storage unit that is given priority for charging is selected from the first type of charging energy storage unit;

[0018] In step 3), the charging energy storage unit that powers the wake-up circuit of the passive tag is selected from the first type of charging energy storage unit;

[0019] B. For the second type of charging energy storage unit: under the premise that the first type of charging energy storage unit is normally powered by the wake-up circuit, the second type of charging energy storage unit is charged; when the wake-up circuit is abnormal, the first type of charging energy storage unit is switched to be charged first.

[0020] The second type of charging energy storage unit contains multiple charging energy storage units. When supplying power to the application load, if the voltage of one of the charging energy storage units in the second type of charging energy storage unit is lower than the minimum threshold, the power supply to the application load is switched to other charging energy storage units in the second type of charging energy storage unit.

[0021] A passive tag based on multiple energy storage units employing the aforementioned sleep method includes a power management circuit, a wake-up circuit, and an energy harvesting circuit. It also includes multiple rechargeable energy storage units.

[0022] The charging terminals of each charging energy storage unit are connected to the output terminal of the energy harvesting circuit under the control of the power management circuit.

[0023] Under the control of the power management circuit, the discharge terminal of the charging energy storage unit can be connected to the power supply terminal of the wake-up circuit or the power supply terminal of the applied load in an open / closed manner.

[0024] The charging energy storage units are divided into two categories: a first category of charging energy storage units that are isolated from each other and supply power to the wake-up circuit, and a second category of charging energy storage units that supply power to the application load; each category of charging energy storage units has one or more identical charging energy storage units.

[0025] The discharge terminal of the first type of rechargeable energy storage unit can be connected to the power supply terminal of the wake-up circuit in an open / closed manner.

[0026] The discharge terminal of the second type of rechargeable energy storage unit can be connected to the power supply terminal of the application load in an open / closed manner;

[0027] The charging terminals of the first type of rechargeable energy storage unit and the second type of rechargeable energy storage unit are isolated from each other.

[0028] This invention achieves the following beneficial effects by reconstructing the power supply structure of the passive tag and isolating the power supply of the wake-up circuit from the application load circuit:

[0029] 1. The wake-up circuit is powered solely by the first type of charging energy storage unit, and the power supply voltage is lower than the application load voltage, thus reducing the power consumption of the wake-up circuit.

[0030] 2. The second type of charging energy storage unit is disconnected in the dormant state, reducing the self-leakage loss of the energy storage unit. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a passive tag hibernation system based on dual energy storage units. Detailed Implementation

[0032] This invention will be illustrated using a high-efficiency dual energy storage unit as an example. In this example, the charging energy storage unit uses a capacitor.

[0033] In this example of a passive tag sleep method based on multiple energy storage units, the passive tag includes an energy harvesting circuit, a power management circuit, a first-type charging energy storage unit, a second-type charging energy storage unit, a wake-up circuit, and an application load. The application load of the passive tag can be any type of application, such as a portable device, sensor, external circuit, or wireless transmitter.

[0034] When the passive tag collects energy, the energy harvesting circuit first converts ambient energy such as light and electromagnetic energy into electrical energy to charge the first type of rechargeable energy storage unit. When the energy storage voltage of the first type of rechargeable energy storage unit reaches V1, the power management circuit switches the rechargeable energy storage unit, and the energy harvesting circuit continues to charge the second type of rechargeable energy storage unit. When the voltage of the first type of rechargeable energy storage unit is detected to be less than V2, the power management circuit prioritizes switching the energy harvesting circuit to supply power to the first type of rechargeable energy storage unit.

[0035] When V1>V2, the energy lost (discharge) in the middle of the first energy storage unit is used to power the wake-up circuit.

[0036] When the wake-up circuit of the passive tag receives a wake-up command or a timer starts, the second type of charging energy storage unit supplies power to the application load.

[0037] The power supply to the wake-up circuit and the power supply to the application load are isolated from each other through the first type of charging energy storage unit and the second type of charging energy storage unit.

[0038] In sleep mode, the wake-up circuit is powered by the first type of rechargeable energy storage unit, while the second type of rechargeable energy storage unit is disconnected from the application load. The power consumption of the wake-up circuit can be less than 1uW, which is significantly lower than the power consumption of the application load. Therefore, the capacitance of the first type of rechargeable energy storage unit is lower than that of the second type of rechargeable energy storage unit. The operating voltage of the wake-up circuit can be lower than that of the application load, and the voltage V1 of the first type of rechargeable energy storage unit is lower than that of the second type of rechargeable energy storage unit.

[0039] The overall system block diagram of the passive tag using this method is as follows: Figure 1 As shown, the passive tag of the dual energy storage unit includes an energy harvesting circuit, a power management circuit, a first type of charging energy storage unit C0 (capacitor), a second type of charging energy storage unit C1 (capacitor), a wake-up circuit, and an application load.

[0040] The energy harvesting circuit can operate normally in the dormant state. When the external ambient energy is greater than the start-up threshold, it draws energy from the outside and charges the charging energy storage unit through the power management circuit.

[0041] The power management circuit operates according to the following logic when the passive tag charging energy storage unit is charging:

[0042] 1. The energy harvesting circuit charges the first type of charging energy storage unit C0 through the power management circuit.

[0043] 2. When the voltage of the first type of charging energy storage unit C0 reaches V1, the power management circuit switches to the second type of charging energy storage unit C1 and starts charging the second type of charging energy storage unit.

[0044] 3. When the voltage of the first type of charging energy storage unit drops to the voltage V2 of the second type of charging energy storage unit (V2 < V1), the power management circuit switches to the first type of charging energy storage unit C0 and starts charging.

[0045] 4. When the power management circuit detects that the voltage input by the energy harvesting circuit is lower than the voltage of the energy storage unit and fails to charge the energy storage unit, the power management circuit disconnects the connection with the charging energy storage unit.

[0046] In the sleep state, the first type of charging energy storage unit C0 continuously powers the wake-up circuit. When no wake-up command is received, the switch between the second type of charging energy storage unit C1 and the application load is disconnected, maintaining an open circuit state to reduce its own leakage current. When a wake-up command is received, the switch between the second type of charging energy storage unit C1 and the application load is closed to supply energy to the application load, and the passive tag enters the working state. The first type of charging energy storage unit C0 and the second type of charging energy storage unit C1 are isolated from each other; the charge capacity of the first type of charging energy storage unit C0 is less than that of the second type of charging energy storage unit C1, and V1 is less than the stable voltage of the second type of charging energy storage unit after charging.

[0047] The wake-up circuit can adopt low-power wake-up methods such as demodulating wake-up signals or timer timing; the low voltage of the first type of charging energy storage unit C0 is beneficial to further reduce the power consumption of the wake-up circuit.

[0048] The application load can be any type of application, including sensors, external circuits, or wireless transmitters, etc., and is in a completely silent state in the sleep state without consuming power.

Claims

1. A passive tag hibernation method based on multiple energy storage units, characterized by the following steps: include: 1) Establish multiple charging energy storage units within the tag; 2) The passive tag is in a dormant state, collecting energy and converting ambient energy into electrical energy to charge the energy storage unit; Charging selection: The voltage of each charging energy storage unit is detected. If the detected voltage Vt of the t-th charging energy storage unit is the lowest, then the t-th charging energy storage unit with the lowest voltage is charged first. Charging is stopped when Vt reaches the maximum threshold, and the charging energy storage unit with the lowest voltage among the other charging energy storage units is switched to charge. That is, the charging energy storage unit with the lowest voltage is charged first. 3) Selection of unit discharge for charging and energy storage to power the wake-up circuit: After charging in step 2), Vt is at its highest, and the t-th charging energy storage unit powers the wake-up circuit of the passive tag; until Vt is lower than the maximum voltage in the charging energy storage unit, the charging energy storage unit corresponding to the maximum voltage powers the wake-up circuit of the passive tag; that is, the charging energy storage unit with the highest voltage is preferentially used to power the wake-up circuit of the passive tag. 4) When the passive tag is in working condition, it provides power selection for the application load: When the wake-up circuit receives a wake-up command, or when the passive tag starts on a timer, the passive tag powers the application load. Multiple charging energy storage units are divided into a first type of charging energy storage unit that is isolated from each other and supplies power to the wake-up circuit, and a second type of charging energy storage unit that supplies power to the application load; each type of charging energy storage unit has one or more identical charging energy storage units. A. For the first type of rechargeable energy storage unit: when the charging voltage is lower than its detection voltage, disconnect it from the charging circuit; In step 2), the charging energy storage unit that is given priority for charging is selected from the first type of charging energy storage unit; In step 3), the charging energy storage unit that powers the wake-up circuit of the passive tag is selected from the first type of charging energy storage unit; B. For the second type of charging energy storage unit: under the premise that the first type of charging energy storage unit is normally powered by the wake-up circuit, the second type of charging energy storage unit is charged; when the wake-up circuit is abnormal, the first type of charging energy storage unit is switched to be charged first. The second type of charging energy storage unit contains multiple charging energy storage units. When supplying power to the application load, if the voltage of one of the charging energy storage units in the second type of charging energy storage unit is lower than the minimum threshold, the power supply to the application load is switched to other charging energy storage units in the second type of charging energy storage unit. The capacity of the first type of charging energy storage unit is smaller than that of the second type of charging energy storage unit. When the passive tag is in a dormant state, disconnect the connection between the charging energy storage unit in the second type of charging energy storage unit and the application load.

2. The passive tag hibernation method based on multiple energy storage units according to claim 1, characterized in that: The wake-up circuit uses either demodulated wake-up signaling or timer-based wake-up methods.

3. A passive tag based on multiple energy storage units employing the hibernation method described in claim 1, comprising a power management circuit, a wake-up circuit, and an energy harvesting circuit, characterized in that... It also includes multiple charging energy storage units; The charging terminals of each charging energy storage unit are connected to the output terminal of the energy harvesting circuit under the control of the power management circuit. Under the control of the power management circuit, the discharge terminal of the charging energy storage unit can be connected to the power terminal of the wake-up circuit or the power terminal of the applied load in an open / closed manner. The charging energy storage units are divided into two categories: a first category of charging energy storage units that are isolated from each other and supply power to the wake-up circuit, and a second category of charging energy storage units that supply power to the application load; each category of charging energy storage units has one or more identical charging energy storage units. The discharge terminal of the first type of rechargeable energy storage unit can be connected to the power supply terminal of the wake-up circuit in an open / closed manner. The discharge terminal of the second type of rechargeable energy storage unit can be connected to the power supply terminal of the application load in an open / closed manner; The charging terminals of the first type of rechargeable energy storage unit and the second type of rechargeable energy storage unit are isolated from each other. The capacity of the first type of rechargeable energy storage unit is smaller than that of the second type of rechargeable energy storage unit.

4. The passive tag based on multiple energy storage units according to claim 3, characterized in that: The first type of charging energy storage unit has one charging energy storage unit, and the second type of charging energy storage unit has one charging energy storage unit.

5. The passive tag based on multiple energy storage units according to claim 3, characterized in that: The types of payloads for passive tags include: portable devices, sensors, external circuits, or wireless transmitters.

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