Passive tag dormancy method based on multiple energy storage units and passive tag

Abstract

The invention discloses a passive tag dormancy method based on multiple energy storage units and a passive tag. The method comprises the following steps: 1) establishing a plurality of charging energy storage units in a label; 2) the passive tag is in a dormant state, collects energy, converts external environment energy into electric energy, and charges the charging energy storage unit; the charging energy storage unit with the lowest voltage is charged preferentially; 3) preferentially adopting the charging energy storage unit with the highest voltage to supply energy to the wake-up circuit; and 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 regular time, the passive tag supplies energy to the application load. The passive tag comprises a power management circuit, a wake-up circuit, an energy collection circuit and a plurality of charging energy storage units. The charging end of each charging energy storage unit is connected with the output end of the energy collection circuit. And the discharge end of the discharge circuit is connected with the power end of the wake-up circuit or the power end of the application load in an opening / closing manner.

Description

Technical Field

[0001] The present invention belongs to the field of communication technology and relates to a passive tag energy-saving technology for Internet of Things communications, specifically a passive RFID tag sleep method based on multiple energy storage units and a passive tag. Background Art

[0002] The development of the Internet of Things (IoT) requires integration with data algorithms, and the recent growth of artificial intelligence has driven a massive demand for data. Expanding the coverage area of ​​sensor nodes and increasing the depth of information collected will be inevitable future trends. However, traditional IoT nodes are limited by power, battery life, and high maintenance costs, making widespread adoption difficult. To address this, academia and industry have initiated extensive research into passive tags.

[0003] Passive tags typically operate at frequencies between 860 and 960 MHz. They lack an internal power supply and therefore typically derive their operating energy from radio frequency (RF) energy harvesting. Consequently, their communication range is limited by the reader, typically less than 10 meters. A tag consists primarily of a tag antenna, a baseband control unit, and a storage unit. The storage unit primarily stores information about the target item, while the tag antenna facilitates communication with the reader. When an RFID system is operating, the reader emits an electromagnetic signal. Upon receiving the signal within the reader's operating area, the tag transfers some of the energy to a rectifier circuit to generate DC power. The RF front-end then demodulates the signal to obtain valid information.

[0004] As the above explanation demonstrates, while passive tags can extract energy from their surroundings to power their continued operation and, when necessary, communication, this energy is relatively weak and highly unstable. Therefore, ensuring extremely low standby power consumption for passive tags without energy input is a crucial issue.

[0005] Existing technologies often only control the tag to enter sleep mode through the digital baseband, but ignore the optimizable aspects such as the leakage of energy storage components and the power supply voltage of the tag itself. Summary of the Invention

[0006] In order to reduce the standby power consumption of passive tags, this paper proposes a passive tag sleep method based on multiple energy storage units, which reduces the standby power consumption of passive tags by optimizing the power supply architecture of passive tags. The specific solution is as follows: A passive tag sleep method based on multiple energy storage units, comprising the following steps: 1) Create multiple charging and energy storage units in the tag; 2) The passive tag is in a dormant state, collecting energy and converting it into electrical energy to charge the energy storage unit; Charging selection: Detect the voltage of each charging energy storage unit. If the detection 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 will be charged first. After Vt reaches the maximum threshold, charging is terminated and the charging energy storage unit with the lowest voltage among the other charging energy storage units is switched to be charged. In other words, the charging energy storage unit with the lowest voltage is charged first. 3) Discharge selection of the unit that charges the energy storage to power the wake-up circuit: After charging in step 2), Vt is the highest, and the tth charging energy storage unit supplies energy to the passive tag's wake-up circuit. Until Vt falls below the maximum voltage of the charging energy storage unit, the charging energy storage unit corresponding to the maximum voltage supplies energy to the passive tag's wake-up circuit. That is, the charging energy storage unit with the highest voltage is preferentially used to supply energy to the passive tag's wake-up circuit. 4) The passive tag is in working state and provides energy for the applied load: When the wake-up circuit of the passive tag receives a wake-up command, or the passive tag is started at a scheduled time, the passive tag supplies energy to the application load.

[0007] 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 energy to the wake-up circuit, and a second type of charging energy storage unit that supplies energy to the application load; each of the two types of charging energy storage units has one or multiple identical charging energy storage sub-units; A. For the first type of charging energy storage unit: when the charging voltage is lower than its detection voltage, the connection between it and the charging circuit is disconnected; In step 2), the charging energy storage unit to be charged first is selected from the first type of charging energy storage units; In step 3), the charging energy storage unit that supplies energy to the wake-up circuit of the passive tag is selected from the first type of charging energy storage units; B. For the second type of charging energy storage unit: when the first type of charging energy storage unit is normally supplying energy to the wake-up circuit, the second type of charging energy storage unit is charged; when the wake-up circuit is supplying energy abnormally, the charging of the first type of charging energy storage unit is prioritized; The second type of charging energy storage unit includes multiple charging energy storage units. When supplying energy to the application load, when the voltage of one of the second type of charging energy storage units is lower than the minimum threshold, the other charging energy storage units in the second type of charging energy storage units are switched to supply energy to the application load.

[0008] A passive tag based on multiple energy storage units using the above-mentioned sleep method includes a power management circuit, a wake-up circuit, and an energy harvesting circuit. It also includes multiple charging energy storage units; The charging terminals of each charging energy storage unit are connected to the output terminals of the energy collection circuit under the control of the power management circuit; Under the control of the power management circuit, the discharge end of the charging energy storage unit can be connected to the power end of the wake-up circuit or the power end of the application load in an open / closed manner.

[0009] The charging energy storage unit is divided into a first type of charging energy storage unit that is isolated from each other and supplies energy to the wake-up circuit, and a second type of charging energy storage unit that supplies energy to the application load; each of the two types of charging energy storage units has one or multiple charging energy storage units of the same type; The discharge end of the first type of charging energy storage unit can be connected to the power supply end of the wake-up circuit in an open / closed manner; The discharge terminal of the second type of charging energy storage unit can be connected to the power supply terminal of the application load in an open / closed manner; The charging end of the first type of charging energy storage unit is isolated from the charging end of the second type of charging energy storage unit.

[0010] The present invention reconstructs the power supply structure of the passive tag to isolate the energy supply of the wake-up circuit from the application load circuit, thereby achieving the following beneficial effects: 1. Use the first type of charging energy storage unit alone to power the wake-up circuit. The supply voltage is lower than the application load voltage, reducing the power consumption of the wake-up circuit.

[0011] 2. The second type of charging energy storage unit is disconnected in the dormant state to reduce the self-leakage loss of the energy storage unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of a passive tag sleep system based on dual energy storage units. DETAILED DESCRIPTION

[0013] The embodiment of the present invention is described by taking a dual energy storage unit with high efficiency as an example. In this example, the charging energy storage unit adopts a capacitor.

[0014] In this example, the passive tag sleep method based on multiple energy storage units includes an energy harvesting circuit, a power management circuit, a first-type rechargeable energy storage unit, a second-type rechargeable energy storage unit, a wake-up circuit, and an application load. The passive tag's application load can be any type of application, such as a portable device, a sensor, an external circuit, or a wireless transmitter.

[0015] When a 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 charging energy storage unit. When the power management circuit detects that the energy storage voltage of the first type of charging energy storage unit has reached V1, it switches to the charging energy storage unit, and the energy harvesting circuit continues to charge the second type of charging energy storage unit. When the power management circuit detects that the voltage of the first type of charging energy storage unit is less than V2, it prioritizes switching to the energy harvesting circuit to power the first type of charging energy storage unit.

[0016] When V1 > V2, the energy (discharge) lost in the middle of the first energy storage unit is used to supply power to the wake-up circuit.

[0017] When the wake-up circuit of the passive tag receives a wake-up command or starts timing, the second type of charging energy storage unit supplies energy to the application load.

[0018] The energy supply of the wake-up circuit and the energy supply of 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.

[0019] In the sleep mode, the first type of charging energy storage unit supplies energy to the wake-up circuit, and the second type of charging energy storage unit disconnects from the application load. The power consumption of the wake-up circuit can be lower than 1 μW, which is much lower than the power consumption of the application load. Therefore, the capacitance value of the first type of charging energy storage unit is lower than that of the second type of charging 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 charging energy storage unit is lower than that of the second type of charging energy storage unit.

[0020] The overall system block diagram of the passive tag using this method is as Figure 1 shown. The passive tag with dual energy storage units 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.

[0021] The energy harvesting circuit can work normally in the sleep state. When the external environmental energy is greater than the startup threshold, it extracts energy from the outside and charges the charging energy storage unit through the power management circuit.

[0022] The working logic of the power management circuit when charging the charging energy storage unit of the passive tag is as follows: 1. The energy harvesting circuit charges the first type of charging energy storage unit C0 through the power management circuit.

[0023] 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.

[0024] 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.

[0025] 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 from the energy storage unit.

[0026] In the sleep state, the first type of charging energy storage unit C0 continues to power 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. 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 power capacity of the first type of charging energy storage unit C0 is less than the power capacity 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.

[0027] The wake-up circuit can adopt low-power wake-up methods such as demodulation of wake-up signaling or timer timing; the low voltage of the first type of charging energy storage unit C0 is conducive to further reducing the power consumption of the wake-up circuit.

[0028] The application load can be any type of application, including sensors, external circuits, or wireless transmitters. In the sleep state, it is completely silent and does not consume power.

Claims

1. A passive tag sleep method based on multiple energy storage units, characterized by the following steps: include: 1) Create multiple charging and energy storage units in the tag; 2) The passive tag is in a dormant state, collecting energy and converting it into electrical energy to charge the energy storage unit; Charging selection: Detect the voltage of each charging energy storage unit. If the detection 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 will be charged first. After Vt reaches the maximum threshold, charging is terminated and the charging energy storage unit with the lowest voltage among the other charging energy storage units is switched to be charged. In other words, the charging energy storage unit with the lowest voltage is charged first. 3) Discharge selection of the unit that charges the energy storage to power the wake-up circuit: After charging in step 2), Vt is the highest, and the tth charging energy storage unit supplies energy to the wake-up circuit of the passive tag. Until Vt falls below the maximum voltage of the charging energy storage unit, the charging energy storage unit corresponding to the maximum voltage supplies energy to the wake-up circuit of the passive tag. That is, the charging energy storage unit with the highest voltage is preferentially used to supply energy to the wake-up circuit of the passive tag. 4) The passive tag is in working state and provides energy for the applied load: When the wake-up circuit receives a wake-up command or the passive tag is started at a scheduled time, the passive tag supplies energy to the application load.

2. The passive tag sleep method based on multiple energy storage units according to claim 1 is characterized in that 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 energy to the wake-up circuit, and a second type of charging energy storage unit that supplies energy to the application load; each of the two types of charging energy storage units includes one or multiple identical charging energy storage units; A. For the first type of charging energy storage unit: when the charging voltage is lower than its detection voltage, the connection between it and the charging circuit is disconnected; In step 2), the charging energy storage unit to be charged first is selected from the first type of charging energy storage units; In step 3), the charging energy storage unit that supplies energy to the wake-up circuit of the passive tag is selected from the first type of charging energy storage units; B. For the second type of charging energy storage unit: when the first type of charging energy storage unit is normally supplying energy to the wake-up circuit, the second type of charging energy storage unit is charged; when the wake-up circuit is supplying energy abnormally, the charging of the first type of charging energy storage unit is prioritized; The second type of charging energy storage unit includes multiple charging energy storage units. When supplying energy to the application load, when the voltage of one of the second type of charging energy storage units is lower than the minimum threshold, the other charging energy storage units in the second type of charging energy storage units are switched to supply energy to the application load.

3. The passive tag sleep method based on multiple energy storage units according to claim 2 is characterized in that The capacity of the first type of charging energy storage unit is smaller than the capacity of the second type of charging energy storage unit.

4. The passive tag sleep method based on multiple energy storage units according to claim 1 is characterized in that The wake-up circuit adopts the wake-up mode of demodulating the wake-up signal or the timer timing.

5. The passive tag sleep method based on multiple energy storage units according to claim 2 is characterized in that When the passive tag is in the dormant state, the connection between the charging energy storage unit in the second type of charging energy storage unit and the application load is disconnected.

6. A passive tag based on multiple energy storage units using the sleep method of claim 1, comprising a power management circuit, a wake-up circuit and an energy harvesting circuit, characterized in that Also included are multiple charging energy storage units; The charging terminals of each charging energy storage unit are connected to the output terminals of the energy collection circuit under the control of the power management circuit; Under the control of the power management circuit, the discharge end of the charging energy storage unit can be connected to the power end of the wake-up circuit or the power end of the application load in an open / closed manner.

7. The passive tag based on multiple energy storage units according to claim 6 is characterized in that the charging The energy storage units are divided into a first type of charging energy storage unit that is isolated from each other and supplies energy to the wake-up circuit, and a second type of charging energy storage unit that supplies energy to the application load; each of the two types of charging energy storage units has one or multiple charging energy storage units of the same type; The discharge end of the first type of charging energy storage unit can be connected to the power supply end of the wake-up circuit in an open / closed manner; The discharge terminal of the second type of charging energy storage unit can be connected to the power supply terminal of the application load in an open / closed manner; The charging end of the first type of charging energy storage unit is isolated from the charging end of the second type of charging energy storage unit.

8. The passive tag based on multiple energy storage units according to claim 6 is characterized in that The capacity of the first type of charging energy storage unit is smaller than the capacity of the second type of charging energy storage unit.

9. The passive tag based on multiple energy storage units according to claim 7 is 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.

10. The passive tag based on multiple energy storage units according to claim 7, characterized in that Types of application loads for passive tags include: portable devices, sensors, external circuits, or wireless transmitters.

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