Wireless temperature sensor and wireless temperature sensor network

Abstract

The invention provides a wireless temperature sensor and a wireless temperature sensor network, and relates to the technical field of sensors, the wireless temperature sensor comprises a power supply module, a measuring module and a transmitting module; the power supply module is used for providing working voltage; the measuring module comprises a temperature sensing bias unit and a voltage-controlled oscillation unit; the temperature sensing bias unit is used for converting an acquired environment temperature parameter into a reference voltage signal and sending the reference voltage signal to the voltage-controlled oscillation unit; the voltage-controlled oscillation unit is used for converting the reference voltage signal into an oscillation frequency signal; and the transmitting module is connected with the frequency signal output end of any anti-phase unit in the voltage-controlled oscillation unit and is used for transmitting the oscillation frequency signal. According to the wireless temperature sensor and the wireless temperature sensor network provided by the invention, integration of signal conversion and signal transmission of temperature is realized, and the power consumption and the cost of the wireless temperature sensor are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and particularly to a wireless temperature sensor and a wireless temperature sensor network. Background Art

[0002] The energy of a self-powered wireless temperature sensor network comes from the environment, so it is very weak. Therefore, the power consumption requirements for wireless sensor nodes are very strict, for example, less than 1 mW (milliwatt).

[0003] Therefore, how to reduce the power consumption and cost of wireless temperature sensors has become a technical problem that the industry urgently needs to solve. Summary of the Invention

[0004] The present invention provides a wireless temperature sensor and a wireless temperature sensor network, which are used to solve the technical problem of how to reduce the power consumption and cost of wireless temperature sensors.

[0005] The present invention provides a wireless temperature sensor, which includes a power supply module, a measurement module, and a transmission module; The power supply module is used to provide a working voltage; The measurement module includes a temperature-sensitive bias unit and a voltage-controlled oscillation unit; The power input terminal of the temperature-sensitive bias unit is connected to the power supply module, and the signal output terminal is connected to the voltage-controlled oscillation unit. It is used to convert the collected environmental temperature parameter into a reference voltage signal and send the reference voltage signal to the voltage-controlled oscillation unit; The voltage-controlled oscillation unit includes an odd number of inverter units, which are used to convert the reference voltage signal into an oscillation frequency signal; the power input terminal of the inverter unit is connected to the power supply module, and the voltage signal input terminal is connected to the signal output terminal of the temperature-sensitive bias unit; the odd number of inverter units are connected in series end to end to form a ring oscillator circuit; The transmission module is connected to the frequency signal output terminal of any one of the inverter units in the voltage-controlled oscillation unit, and is used to transmit the oscillation frequency signal.

[0006] In some embodiments, the temperature-sensitive bias unit includes a constant current source, a first PMOS transistor, a second PMOS transistor, a third PMOS transistor, a fourth PMOS transistor, a first NMOS transistor, a second NMOS transistor, a third NMOS transistor, a first resistor, and a second resistor; The source of the first PMOS transistor is connected to the power supply module, the drain is connected to the positive pole of the constant current source, and the gate is connected to the drain of the first PMOS transistor; The negative pole of the constant current source is connected to the ground terminal; The source of the second PMOS transistor is connected to the power supply module, the drain is connected to the first end of the first resistor, and the gate is connected to the gate of the first PMOS transistor; The source of the third PMOS transistor is connected to the power supply module, the drain is connected to the drain of the first NMOS transistor, and the gate is connected to the gate of the first PMOS transistor; The source of the fourth PMOS transistor is connected to the power supply module, the drain is connected to the drain of the second NMOS transistor, and the gate is connected to the drain of the fourth PMOS transistor; the gate of the fourth PMOS transistor is the signal output end of the temperature sensing bias unit; The source of the first NMOS transistor is connected to the ground terminal, and the drain is connected to the gate of the first NMOS transistor; The source of the second NMOS transistor is connected to the ground terminal, and the gate is connected to the gate of the first NMOS transistor; The source of the third NMOS transistor is connected to the first end of the second resistor, the drain is connected to the gate of the fourth PMOS transistor, and the gate is connected to the first end of the first resistor; The second end of the first resistor is connected to the ground terminal; The second end of the second resistor is connected to the ground terminal; The first resistor is a thermistor.

[0007] In some embodiments, the inverting unit includes a fifth PMOS transistor, a sixth PMOS transistor, a seventh PMOS transistor, an eighth PMOS transistor, a fourth NMOS transistor, a fifth NMOS transistor, a sixth NMOS transistor, a first variable capacitor, and a second variable capacitor; The source of the fifth PMOS transistor is connected to the power supply module, the drain is connected to the drain of the fourth NMOS transistor, and the gate is the voltage signal input terminal; The source of the sixth PMOS transistor is connected to the power supply module, the drain is connected to the source of the seventh PMOS transistor, and the gate is connected to the gate of the fifth PMOS transistor; The drain of the seventh PMOS transistor is the positive voltage output terminal of the inverting unit, and the gate is the positive voltage input terminal of the inverting unit; The source of the eighth PMOS transistor is connected to the drain of the sixth PMOS transistor, the drain is the negative voltage output terminal of the inverting unit, and the gate is the negative voltage input terminal of the inverting unit; The source of the fourth NMOS transistor is connected to the ground terminal, the drain is connected to the gate of the fourth NMOS transistor, and the gate is connected to the gate of the sixth NMOS transistor; The source of the fifth NMOS transistor is connected to the ground terminal, the drain is connected to the drain of the seventh PMOS transistor, and the gate is connected to the gate of the fourth NMOS transistor; The source of the sixth NMOS transistor is connected to the ground terminal, the drain is connected to the drain of the eighth PMOS transistor, and the gate is connected to the gate of the fourth NMOS transistor; The first terminal of the first variable capacitor is connected to the drain of the seventh PMOS transistor, and the second terminal is connected to the ground terminal; The first terminal of the second variable capacitor is connected to the drain of the eighth PMOS transistor, and the second terminal is connected to the ground terminal.

[0008] In some embodiments, the first variable capacitor and the second variable capacitor are the same capacitive circuit.

[0009] In some embodiments, the capacitive circuit includes a plurality of parallel capacitive branches; the capacitive branch includes a capacitor and a switch module; The first terminal of the capacitor is the first terminal of the capacitive circuit, and the second terminal is connected to the first connection terminal of the switch module; The second connection terminal of the switch module is the second terminal of the capacitive circuit; The capacitive branch is configured to connect the capacitor to the capacitive circuit when the switch module is turned on.

[0010] In some embodiments, the switch module includes a ninth PMOS transistor, a tenth PMOS transistor, a ninth NMOS transistor, and a tenth NMOS transistor; The source of the ninth PMOS transistor is the second connection terminal of the switch module, the drain is the first connection terminal of the switch module, and the gate is the conduction signal input terminal; The source of the tenth PMOS transistor is connected to the gate of the ninth NMOS transistor, the drain is connected to the power supply module, and the gate is connected to the gate of the ninth PMOS transistor; The source of the ninth NMOS transistor is connected to the drain of the ninth PMOS transistor, and the drain is connected to the source of the ninth PMOS transistor; The source of the tenth NMOS transistor is connected to the source of the tenth PMOS transistor, the drain is connected to the ground terminal, and the gate is connected to the gate of the ninth PMOS transistor.

[0011] In some embodiments, the number of inverting units in the voltage-controlled oscillation unit is determined based on the operating frequency band of the wireless temperature sensor.

[0012] In some embodiments, the power supply module includes a thermoelectric power generation unit, an energy management unit, and an energy storage unit; The thermoelectric power generation unit is configured to generate electrical energy based on the ambient temperature difference; The energy storage unit is used to store electrical energy; The energy management unit is connected to the thermoelectric power generation unit and the energy storage unit, and is configured to transmit the electrical energy generated by the thermoelectric power generation unit to the energy storage unit, and provide a working voltage to the measurement module based on the electrical energy generated by the thermoelectric power generation unit and / or the electrical energy stored in the energy storage unit.

[0013] The present invention provides a wireless temperature sensor network including the wireless temperature sensor described above.

[0014] In some embodiments, the operating frequency bands of the respective wireless temperature sensors are all different.

[0015] The wireless temperature sensor and the wireless temperature sensor network provided by the present invention include a power supply module, a measurement module, and a transmission module; the measurement module integrates a temperature sensing bias unit and a voltage controlled oscillator unit. Since the voltage controlled oscillator unit adopts a ring oscillator structure composed of an odd number of inverter units, the process cost is reduced compared with an LC oscillator, and the operating frequency band is increased compared with an RC oscillator; overall, the integration of temperature signal conversion and signal transmission is achieved, and the power consumption and cost of the wireless temperature sensor are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present invention, and are used together with the specification to explain the principles of the present invention.

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 It is a schematic structural diagram of the wireless temperature sensor provided by the present invention.

[0019] Figure 2 It is a schematic structural diagram of the temperature sensing bias unit provided by the present invention.

[0020] Figure 3 It is a schematic structural diagram of the inverter unit provided by the present invention.

[0021] Figure 4 It is a schematic structural diagram of the measurement module provided by the present invention.

[0022] Figure 5 It is a schematic diagram of node frequency band division provided by the present invention.

[0023] Figure 6 It is a schematic structural diagram of the variable capacitance circuit provided by the present invention.

[0024] Figure 7 It is a schematic structural diagram of the switch module provided by the present invention.

[0025] Figure 8 It is a schematic structural diagram of the power supply module provided by the present invention.

[0026] Figure 9 It is a schematic structural diagram of the wireless temperature sensor network provided by the present invention. Detailed implementation manners

[0027] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0028] It should be noted that the terms "first", "second", etc. in the present invention are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order different from those illustrated or described here. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units or modules does not have to be limited to those clearly listed steps or units or modules, but may include other steps or units or modules not clearly listed or inherent to these processes, methods, products or devices.

[0029] Traditional temperature sensors need to convert temperature into an analog signal first, and then convert it into a digital signal through an analog-to-digital converter (ADC) or a counter, which increases power consumption. To reduce power consumption, the analog-to-digital converter, processor, and wireless transceiver in the temperature sensor node are omitted, and only the analog signal of the temperature sensor is used to control a voltage-controlled oscillator (VCO) to obtain the relationship between temperature and frequency. The voltage-controlled oscillator outputs through a buffer and transmits an FM frequency modulation signal through an antenna. Oscillators mainly include RC (resistor, capacitor) oscillators and LC (inductor, capacitor) oscillators. Since it is difficult to increase the working frequency band of RC oscillators, this will cause the size of the transmitting antenna to be very large. Although the LC oscillator structure can work at a very high frequency, due to the presence of inductors, the process cost increases (radio frequency technology is required).

[0030] To solve the deficiencies of the related technologies, Figure 1 is a schematic structural diagram of the wireless temperature sensor provided by the present invention, as Figure 1 shown, the wireless temperature sensor 100 includes a power supply module 110, a measurement module 120, and a transmission module 130. The measurement module 120 includes a temperature sensing bias unit 121 and a voltage-controlled oscillation unit 122.

[0031] The power supply module is used to provide the working voltage.

[0032] The power input terminal of the temperature sensing bias unit is connected to the power supply module, and the signal output terminal is connected to the voltage-controlled oscillation unit, and is used to convert the collected ambient temperature parameter into a reference voltage signal and send the reference voltage signal to the voltage-controlled oscillation unit.

[0033] The voltage-controlled oscillation unit includes an odd number of inverter units, and is used to convert the reference voltage signal into an oscillation frequency signal; the power input terminal of the inverter unit is connected to the power supply module, and the voltage signal input terminal is connected to the signal output terminal of the temperature sensing bias unit; the odd number of inverter units are sequentially connected end to end to form a ring oscillator circuit.

[0034] The transmission module is connected to the frequency signal output terminal of any inverter unit in the voltage-controlled oscillation unit, and is used to transmit the oscillation frequency signal.

[0035] Specifically, the wireless temperature sensor provided by the embodiments of the present invention is used to transmit temperature data wirelessly, can be widely applied to multiple fields, is convenient to install and simple to maintain. From a structural perspective, the wireless temperature sensor mainly includes a power supply module, a measurement module, and a transmission module.

[0036] The power supply module is mainly used to provide the working voltage for the measurement module, so that each electronic component in the measurement module can work normally.

[0037] The measurement module integrates the functions of temperature signal conversion and transmission, and mainly includes a temperature-sensitive bias unit and a voltage-controlled oscillator unit.

[0038] The temperature-sensitive bias unit can collect the ambient temperature (the temperature to be measured) through an internally set thermosensitive element (such as a thermistor). The power input terminal of the temperature-sensitive bias unit is connected to the power supply module to provide a working voltage for the thermosensitive element. According to the parameter changes of the thermosensitive element, a reference voltage signal that changes with the parameter changes is generated and sent to the voltage-controlled oscillator unit through the signal output terminal.

[0039] The voltage-controlled oscillator unit uses a ring oscillator to convert the reference voltage signal into an oscillation frequency signal. The voltage-controlled oscillator unit is mainly composed of an odd number of inverter units connected end to end in sequence. The power input terminal of the inverter unit is connected to the power supply module, and the voltage signal input terminal is connected to the signal output terminal of the temperature-sensitive bias unit. The function of each inverter unit is to reverse the phase of the reference voltage signal by 180° (that is, the high level becomes the low level, and the low level becomes the high level). Since the number of inverter units is odd, when the signal passes through all the inverter units and finally returns to the starting point, the phase will be reversed, thus forming a positive feedback loop. This positive feedback loop will cause the circuit to oscillate and generate an oscillation frequency signal.

[0040] The transmitting unit can be an antenna, which is connected to the frequency signal output terminal of any inverter unit in the voltage-controlled oscillator unit for transmitting the oscillation frequency signal.

[0041] The wireless temperature sensor provided by the embodiment of the present invention includes a power supply module, a measurement module and a transmitting module; the measurement module integrates a temperature-sensitive bias unit and a voltage-controlled oscillator unit. Since the voltage-controlled oscillator unit adopts a ring oscillator structure composed of an odd number of inverter units, compared with the LC oscillator, the process cost is reduced, and compared with the RC oscillator, the working frequency band is increased; overall, the integration of temperature signal conversion and signal transmission is realized, and the power consumption and cost of the wireless temperature sensor are reduced.

[0042] In some embodiments, Figure 2 is a schematic structural diagram of the temperature-sensitive bias unit provided by the present invention. As Figure 2 shown, the temperature-sensitive bias unit includes a constant current source, a first PMOS transistor (PM1), a second PMOS transistor (PM2), a third PMOS transistor (PM3), a fourth PMOS transistor (PM4), a first NMOS transistor (NM1), a second NMOS transistor (NM2), a third NMOS transistor (NM3), a first resistor (R1) and a second resistor (R2).

[0043] The source electrode of the first PMOS transistor is connected to the power supply module, the drain electrode is connected to the positive electrode of the constant current source, and the gate electrode is connected to the drain electrode of the first PMOS transistor; The negative electrode of the constant current source is connected to the ground terminal (GND); The source electrode of the second PMOS transistor is connected to the power supply module, the drain electrode is connected to the first end of the first resistor, and the gate electrode is connected to the gate electrode of the first PMOS transistor; The source electrode of the third PMOS transistor is connected to the power supply module, the drain electrode is connected to the drain electrode of the first NMOS transistor, and the gate electrode is connected to the gate electrode of the first PMOS transistor; The source electrode of the fourth PMOS transistor is connected to the power supply module, the drain electrode is connected to the drain electrode of the second NMOS transistor, and the gate electrode is connected to the drain electrode of the fourth PMOS transistor; the gate electrode of the fourth PMOS transistor is the signal output terminal of the temperature-sensitive bias unit; The source electrode of the first NMOS transistor is connected to the ground terminal, and the drain electrode is connected to the gate electrode of the first NMOS transistor; The source electrode of the second NMOS transistor is connected to the ground terminal, and the gate electrode is connected to the gate electrode of the first NMOS transistor; The source electrode of the third NMOS transistor is connected to the first end of the second resistor, the drain electrode is connected to the gate electrode of the fourth PMOS transistor, and the gate electrode is connected to the first end of the first resistor; The second end of the first resistor is connected to the ground terminal; The second end of the second resistor is connected to the ground terminal; The first resistor is a thermistor.

[0044] Specifically, a MOS transistor (Metal-Oxide-Semiconductor Field-Effect Transistor) is an important semiconductor device and can be divided into a PMOS transistor and an NMOS transistor. A constant current source is a power supply device that can provide a stable current output, and its output current does not change with the change of the load resistance. The magnitude of the output current of the constant current source can be denoted as IDC.

[0045] The temperature-sensitive bias unit is mainly composed of 4 PMOS transistors, 3 NMOS transistors, 1 thermistor, 1 constant current source, and 1 ordinary resistor. Among them, the first PMOS transistor (PM1), the second PMOS transistor (PM2), and the third PMOS transistor (PM3) have the same size, and the first NMOS transistor (NM1) and the second NMOS transistor (NM2) have the same size. The operating voltage provided by the power supply module is VDD.

[0046] For the third NMOS transistor (NM3), the following relational expression exists: Among them, is the current flowing through the third NMOS transistor, is the voltage at the first end of the first resistor, is the resistance value of the second resistor, is the transconductance of the third NMOS transistor.

[0047] According to the above formula, it can be obtained that: Because , is the current flowing through the first resistor, is the resistance value of the first resistor. For the fourth PMOS transistor, the following relational expression exists: Among them, is the current flowing through the second NMOS transistor, is the current flowing through the fourth PMOS transistor. From the above relational expressions, it can be obtained that: Because , it can be obtained that: It can be seen from this that when the thermistor increases, can increase accordingly, and the reference voltage signal also increases accordingly.

[0048] In the wireless temperature sensor provided by the embodiment of the present invention, the temperature sensing bias unit is composed of MOS transistors, and there is no need to convert into a digital signal by an analog-to-digital converter or a counter, reducing power consumption.

[0049] In some embodiments, Figure 3 is a schematic structural diagram of the inverter unit provided by the present invention. As Figure 3 shown, the inverter unit includes a fifth PMOS transistor (PM5), a sixth PMOS transistor (PM6), a seventh PMOS transistor (PM7), an eighth PMOS transistor (PM8), a fourth NMOS transistor (NM4), a fifth NMOS transistor (NM5), a sixth NMOS transistor (NM6), a first variable capacitor (CL1), and a second variable capacitor (CL2).

[0050] The source of the fifth PMOS transistor is connected to the power supply module, the drain is connected to the drain of the fourth NMOS transistor, and the gate is the voltage signal input terminal; The source of the sixth PMOS transistor is connected to the power supply module, the drain is connected to the source of the seventh PMOS transistor, and the gate is connected to the gate of the fifth PMOS transistor; The drain of the seventh PMOS transistor is the positive voltage output terminal (Vop) of the inverter unit, and the gate is the positive voltage input terminal (Vip) of the inverter unit; The source of the eighth PMOS transistor is connected to the drain of the sixth PMOS transistor. The drain is the negative voltage output terminal (Von) of the inverter unit, and the gate is the negative voltage input terminal (Vin) of the inverter unit. The source of the fourth NMOS transistor is connected to the ground terminal. The drain is connected to the gate of the fourth NMOS transistor, and the gate is connected to the gate of the sixth NMOS transistor. The source of the fifth NMOS transistor is connected to the ground terminal. The drain is connected to the drain of the seventh PMOS transistor, and the gate is connected to the gate of the fourth NMOS transistor. The source of the sixth NMOS transistor is connected to the ground terminal. The drain is connected to the drain of the eighth PMOS transistor, and the gate is connected to the gate of the fourth NMOS transistor. The first terminal of the first variable capacitor is connected to the drain of the seventh PMOS transistor, and the second terminal is connected to the ground terminal. The first terminal of the second variable capacitor is connected to the drain of the eighth PMOS transistor, and the second terminal is connected to the ground terminal.

[0051] Specifically, the inverter unit is mainly composed of 4 PMOS transistors, 3 NMOS transistors and 2 variable capacitors. The gate voltages of the fifth PMOS transistor and the sixth PMOS transistor are the same as the gate voltage of the fourth PMOS transistor in the temperature-sensitive bias unit, which is the voltage of the reference voltage signal. Therefore, And Is in a direct proportional relationship, Is the current flowing through the sixth PMOS transistor.

[0052] The current of determines the oscillator frequency. In this way, the temperature change of R1 is used to control the oscillator frequency: the temperature change causes the resistance value of R1 to change. When the resistance value increases, then The voltage increases, Becomes larger, and Is increased ( Is the current flowing through the sixth NMOS transistor), and finally the oscillation frequency becomes larger. Similarly, when the resistance value of R1 decreases, the oscillation frequency decreases.

[0053] For the wireless temperature sensor provided by the embodiment of the present invention, the inverter unit is composed of MOS transistors, which reduces the power consumption.

[0054] In some embodiments, Figure 4 Is the structural schematic diagram of the measurement module provided by the present invention. As Figure 4 Shown, the measurement module includes a temperature-sensitive bias unit and a voltage-controlled oscillation unit. The voltage-controlled oscillation unit includes n inverter units, and n is an odd number.

[0055] The inverting units are connected end to end. The positive voltage output terminal (Vop) of the previous inverting unit is connected to the positive voltage input terminal (Vip) of the next inverting unit, and the negative voltage output terminal (Von) of the previous inverting unit is connected to the negative voltage input terminal (Vin) of the next inverting unit, forming a ring oscillator structure. This not only improves the working frequency band but also uses only digital CMOS technology, thus reducing costs.

[0056] In some embodiments, the first variable capacitor and the second variable capacitor are the same capacitor circuit.

[0057] Specifically, the voltage-controlled oscillation unit includes an odd number of inverting units. Each inverting unit includes a first variable capacitor and a second variable capacitor, and the capacitor circuits of the first variable capacitor and the second variable capacitor are the same, and the capacitance values are the same, that is, CL1 = CL2. That is, the capacitance values of the variable capacitors in all the inverting units in the voltage-controlled oscillation unit are the same.

[0058] From the circuit structure, it can be seen that the larger the capacitance value of the variable capacitor, the longer the charging and discharging time, and the lower the oscillation frequency. For a wireless temperature sensor, the frequency band (TX_Fi) of the wireless temperature sensor can be determined by setting the variable capacitor.

[0059] Figure 5 It is a schematic diagram of the node frequency band division provided by the present invention. As Figure 5 shown, in a wireless temperature sensor network, there are m wireless temperature sensors. The capacitance values of the variable capacitors in the i-th wireless temperature sensor are CL1 = CL2 = Ci (i = 1, 2,..., m). The variable capacitors in each wireless temperature sensor can be set to decrease monotonically, that is, C1 >... > Cm. Correspondingly, the working frequency bands (TX_F1, TX_F2,..., TX_Fm) of the wireless temperature sensors in the wireless temperature sensor network can be determined to be different. TX_Fi is the working frequency band of the i-th wireless temperature sensor.

[0060] Within each TX_Fi frequency band, R1 changes the frequency with the change of temperature to complete temperature acquisition and conversion.

[0061] In some embodiments, Figure 6 It is a schematic diagram of the structure of the variable capacitor circuit provided by the present invention. As Figure 6 shown, the capacitor circuit includes a plurality of parallel capacitor branches; the capacitor branch includes a capacitor and a switch module; the first end of the capacitor is the first end of the capacitor circuit, and the second end is connected to the first connection end of the switch module; the second connection end of the switch module is the second end of the capacitor circuit; the capacitor branch is configured to connect the capacitor to the capacitor circuit when the switch module is turned on.

[0062] Specifically, for any variable capacitor, there can be n parallel capacitor branches. At the In a capacitor branch, the capacitor can be expressed as C0j, where j = 1, 2, …, n. The switching module can be expressed as T0j. The control signal corresponding to the switching module can be expressed as CTj. The CTj signal controls the conduction and disconnection of the switching module through high and low levels. The capacitor branch is configured to connect the capacitor to the capacitor circuit when the switching module is conducting.

[0063] When setting the capacitors of the wireless temperature sensors in the wireless temperature sensor network, Cm can be set to C01, C m-1 = C01 + C02, …, C1 = C01 + C02 + … + C0n. The switch T0j (j = 1, …, n) is used to control whether the capacitor C0j is selected.

[0064] The wireless temperature sensor provided by the embodiment of the present invention constructs a variable capacitor circuit through parallel capacitor branches, reducing the cost.

[0065] In some embodiments, Figure 7 is a schematic structural diagram of the switching module provided by the present invention. As Figure 7 shown, the switching module includes a ninth PMOS transistor (PM9), a tenth PMOS transistor (PM10), a ninth NMOS transistor (NM9), and a tenth NMOS transistor (NM10).

[0066] The source of the ninth PMOS transistor is the second connection end of the switching module, the drain is the first connection end of the switching module, and the gate is the conduction signal input end; The source of the tenth PMOS transistor is connected to the gate of the ninth NMOS transistor, the drain is connected to the power supply module, and the gate is connected to the gate of the ninth PMOS transistor; The source of the ninth NMOS transistor is connected to the drain of the ninth PMOS transistor, and the drain is connected to the source of the ninth PMOS transistor; The source of the tenth NMOS transistor is connected to the source of the tenth PMOS transistor, the drain is connected to the ground terminal, and the gate is connected to the gate of the ninth PMOS transistor.

[0067] Specifically, the ninth PMOS transistor and the ninth NMOS transistor form the transmission gate of the switch, and the tenth PMOS transistor and the tenth NMOS transistor form an inverter. When CT is at a low level, the switch node 1 (the first connection end of the switching module) and node 2 (the second connection end of the switching module) are conducting. When CT is at a high level, the switch node 1 and node 2 are disconnected. CT is an externally input conduction control signal.

[0068] The wireless temperature sensor provided by the embodiment of the present invention uses MOS for the switching circuit, reducing the cost.

[0069] In some embodiments, the number of inverting units in the voltage-controlled oscillation unit is determined based on the operating frequency of the wireless temperature sensor.

[0070] Specifically, in a wireless temperature sensor, the relationship between the number of inverter units in a voltage-controlled oscillator unit and the operating frequency band can be explained by the design principle of a ring oscillator. The number of inverter units affects the output frequency range of the oscillator, and generally, the lower the operating frequency band, the more inverter units are required.

[0071] In some embodiments, Figure 8 is a schematic structural diagram of a power supply module provided by the present invention, as Figure 8 shown, the power supply module 110 includes a thermoelectric power generation unit 111, an energy management unit 112, and an energy storage unit 113.

[0072] The thermoelectric power generation unit is configured to generate electric energy based on the ambient temperature difference; The energy storage unit is configured to store electric energy; The energy management unit is connected to the thermoelectric power generation unit and the energy storage unit, and is configured to transmit the electric energy generated by the thermoelectric power generation unit to the energy storage unit, and provide a working voltage to the measurement module based on the electric energy generated by the thermoelectric power generation unit and / or the electric energy stored in the energy storage unit.

[0073] Specifically, the thermoelectric power generation unit can utilize the Seebeck effect to generate electric energy according to the ambient temperature difference, thereby reducing the demand for external electric energy. After the thermoelectric power generation unit generates electric energy, the energy management unit collects the electric energy to form a working voltage, and can also store the excess electric energy in the energy storage unit.

[0074] In the wireless temperature sensor provided by the embodiment of the present invention, the power supply module can provide electric energy for the wireless temperature sensor according to the ambient temperature difference, realizing self-power supply and reducing power consumption.

[0075] Figure 9 is a schematic structural diagram of a wireless temperature sensor network provided by the present invention, as Figure 9 shown, the wireless temperature sensor network 900 includes a plurality of wireless temperature sensors 100 in the above embodiments.

[0076] The wireless temperature sensor network provided by the embodiment of the present invention is composed of wireless temperature sensors. As a whole, each temperature sensor realizes the integration of temperature signal conversion and signal transmission, reducing the power consumption and cost of the wireless temperature sensor, and also reducing the power consumption and cost of the wireless temperature sensor network.

[0077] In some embodiments, the variable capacitors in each wireless temperature sensor can be set such that the operating frequency bands of each wireless temperature sensor are different.

[0078] Based on the obtained oscillation frequency signal, not only can the ambient temperature be analyzed, but also the wireless temperature sensor that transmits the oscillation frequency signal can be determined.

[0079] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative effort.

[0080] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the essence of the above technical solution or the part that contributes to the prior art can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of each embodiment of the present invention.

Claims

1. A wireless temperature sensor, characterized in that: It includes a power supply module, a measuring module and a transmitting module; The power supply module is used to provide a working voltage; The measurement module includes a temperature-sensing bias unit and a voltage-controlled oscillation unit; The power input end of the temperature sensing bias unit is connected to the power supply module, and the signal output end is connected to the voltage-controlled oscillation unit, for converting the collected ambient temperature parameters into a reference voltage signal, and sending the reference voltage signal to the voltage-controlled oscillation unit; The voltage-controlled oscillation unit includes an odd number of inverting units, which are used to convert the reference voltage signal into an oscillation frequency signal; the power input end of the inverting unit is connected to the power supply module, and the voltage signal input end is connected to the signal output end of the temperature-sensing bias unit; the odd number of inverting units are connected end to end in sequence to form a ring oscillation circuit; The transmitting module is connected to the frequency signal output end of any inverting unit in the voltage-controlled oscillation unit, and is used to send the oscillation frequency signal.

2. The wireless temperature sensor according to claim 1, characterized in that: The temperature-sensing bias unit includes a constant current source, a first PMOS tube, a second PMOS tube, a third PMOS tube, a fourth PMOS tube, a first NMOS tube, a second NMOS tube, a third NMOS tube, a first resistor and a second resistor; The source of the first PMOS tube is connected to the power supply module, the drain is connected to the positive electrode of the constant current source, and the gate is connected to the drain of the first PMOS tube; The negative electrode of the constant current source is connected to the ground terminal; The source of the second PMOS tube is connected to the power supply module, the drain is connected to the first end of the first resistor, and the gate is connected to the gate of the first PMOS tube; The source of the third PMOS tube is connected to the power supply module, the drain is connected to the drain of the first NMOS tube, and the gate is connected to the gate of the first PMOS tube; The source of the fourth PMOS tube is connected to the power supply module, the drain is connected to the drain of the second NMOS tube, and the gate is connected to the drain of the fourth PMOS tube; the gate of the fourth PMOS tube is the signal output end of the temperature-sensing bias unit; The source of the first NMOS tube is connected to the ground terminal, and the drain is connected to the gate of the first NMOS tube; The source of the second NMOS tube is connected to the ground terminal, and the gate is connected to the gate of the first NMOS tube; The source of the third NMOS transistor is connected to the first end of the second resistor, the drain is connected to the gate of the fourth PMOS transistor, and the gate is connected to the first end of the first resistor; The second end of the first resistor is connected to the ground end; The second end of the second resistor is connected to the ground end; The first resistor is a thermistor.

3. The wireless temperature sensor according to claim 1, characterized in that: The inverting unit includes a fifth PMOS tube, a sixth PMOS tube, a seventh PMOS tube, an eighth PMOS tube, a fourth NMOS tube, a fifth NMOS tube, a sixth NMOS tube, a first variable capacitor and a second variable capacitor; The source of the fifth PMOS tube is connected to the power supply module, the drain is connected to the drain of the fourth NMOS tube, and the gate is the voltage signal input terminal; The source of the sixth PMOS tube is connected to the power supply module, the drain is connected to the source of the seventh PMOS tube, and the gate is connected to the gate of the fifth PMOS tube; The drain of the seventh PMOS tube is the positive voltage output terminal of the inverting unit, and the gate is the positive voltage input terminal of the inverting unit; The source of the eighth PMOS tube is connected to the drain of the sixth PMOS tube, the drain is the negative voltage output terminal of the inverting unit, and the gate is the negative voltage input terminal of the inverting unit; The source of the fourth NMOS tube is connected to the ground terminal, the drain is connected to the gate of the fourth NMOS tube, and the gate is connected to the gate of the sixth NMOS tube; The source of the fifth NMOS tube is connected to the ground terminal, the drain is connected to the drain of the seventh PMOS tube, and the gate is connected to the gate of the fourth NMOS tube; The source of the sixth NMOS tube is connected to the ground terminal, the drain is connected to the drain of the eighth PMOS tube, and the gate is connected to the gate of the fourth NMOS tube; A first end of the first variable capacitor is connected to the drain of the seventh PMOS transistor, and a second end is connected to the ground end; A first end of the second variable capacitor is connected to the drain of the eighth PMOS tube, and a second end of the second variable capacitor is connected to the ground end.

4. The wireless temperature sensor according to claim 3, characterized in that: The first variable capacitor and the second variable capacitor are the same capacitor circuit.

5. The wireless temperature sensor according to claim 4, characterized in that: The capacitor circuit includes a plurality of capacitor branches connected in parallel; the capacitor branches include capacitors and switch modules; The first end of the capacitor is the first end of the capacitor circuit, and the second end is connected to the first connection end of the switch module; The second connection end of the switch module is the second end of the capacitor circuit; The capacitor branch is configured to connect the capacitor to the capacitor circuit when the switch module is turned on.

6. The wireless temperature sensor according to claim 5, characterized in that: The switch module includes a ninth PMOS tube, a tenth PMOS tube, a ninth NMOS tube, and a tenth NMOS tube; The source of the ninth PMOS tube is the second connection terminal of the switch module, the drain is the first connection terminal of the switch module, and the gate is the conduction signal input terminal; The source of the tenth PMOS tube is connected to the gate of the ninth NMOS tube, the drain is connected to the power supply module, and the gate is connected to the gate of the ninth PMOS tube; The source of the ninth NMOS tube is connected to the drain of the ninth PMOS tube, and the drain is connected to the source of the ninth PMOS tube; The source of the tenth NMOS tube is connected to the source of the tenth PMOS tube, the drain is connected to the ground terminal, and the gate is connected to the gate of the ninth PMOS tube.

7. The wireless temperature sensor according to claim 1, characterized in that: The number of inverting units in the voltage-controlled oscillation unit is determined based on the operating frequency band of the wireless temperature sensor.

8. The wireless temperature sensor according to claim 1, characterized in that: The power supply module includes a temperature difference power generation unit, an energy management unit and an energy storage unit; The temperature difference power generation unit is used to generate electric energy based on the ambient temperature difference; The energy storage unit is used to store electrical energy; The energy management unit is connected to the thermoelectric power generation unit and the energy storage unit, and is used to transmit the electric energy generated by the thermoelectric power generation unit to the energy storage unit, and to provide an operating voltage to the measurement module based on the electric energy generated by the thermoelectric power generation unit and / or the electric energy stored in the energy storage unit.

9. A wireless temperature sensor network, characterized in that: The wireless temperature sensor comprises the wireless temperature sensor according to any one of claims 1 to 8.

10. The wireless temperature sensor network according to claim 9, characterized in that: Each wireless temperature sensor operates in a different frequency band.

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