Temperature sampling circuit and air conditioner with same

Abstract

The utility model discloses a temperature sampling circuit, which comprises a thermistor element, a voltage division module, at least two change-over switches and a controller, and is characterized in that the first end of the thermistor element is connected with a power supply; the voltage dividing module comprises a first terminal, a first grounding end and a plurality of voltage dividing resistors arranged between the first terminal and the first grounding end, the first terminal is connected with the second end of the thermistor element, and the first terminal is used for outputting an electric signal representing temperature change; each change-over switch is correspondingly connected with at least one voltage dividing resistor and is used for switching the grounding resistance value of the voltage dividing module so as to control the voltage dividing ratio of the voltage dividing module; the controller is connected with the first terminal and each change-over switch, and the controller is used for generating a temperature sampling value based on the electric signal; and based on the temperature sampling value, a first control signal is output to the change-over switch, and the first control signal is used for switching the switching state of the change-over switch so as to control the conduction state of the at least one divider resistor. The utility model further discloses the air conditioner.

Description

Technical Field

[0001] The present application relates to the field of sampling technology, and in particular to a temperature sampling circuit and an air conditioner having the same. Background Art

[0002] Most temperature sensors currently on the market do not have ideal linear resistance values. For example, for a conventional exhaust pipe temperature sensor, the resistance resolution of the sensor is high in the medium temperature range, but the temperature resolution is not high in the low and high temperature ranges.

[0003] For some machines, it is required to maintain high resolution in both high and low temperature ranges. For example, air conditioners whose refrigerant is carbon dioxide have more advantages in the high temperature range than air conditioners whose refrigerant is refrigerant, so they are widely used. In addition, it is also required to be able to take timely protective measures in harsh low temperature environments.

[0004] Therefore, if the above-mentioned temperature sensor is used, this will cause the machine to be unable to accurately read the temperature value in the low temperature range and the high temperature range and achieve accurate control, thereby reducing the energy efficiency of the machine and user experience. Utility Model Content

[0005] In view of this, the embodiments of the present application provide a temperature sampling circuit and an air conditioner having the same, which can improve the temperature sampling accuracy in the entire temperature range, achieve precise temperature control of the machine, and improve the energy efficiency of the machine.

[0006] The technical solution of the embodiment of the present application is implemented as follows:

[0007] In a first aspect, an embodiment of the present application provides a temperature sampling circuit, wherein the temperature sampling circuit comprises:

[0008] A thermistor element, wherein a first end of the thermistor element is connected to a power supply;

[0009] A voltage dividing module, the voltage dividing module comprising a first terminal, a first ground terminal and a plurality of voltage dividing resistors arranged between the first terminal and the first ground terminal, the first terminal being connected to the second end of the thermistor element, and the first terminal being used to output an electrical signal representing a temperature change;

[0010] At least two switching switches, each of which is connected to at least one voltage-dividing resistor and is used to switch the grounding resistance of the voltage-dividing module to control the voltage-dividing ratio of the voltage-dividing module;

[0011] A controller, wherein the controller is respectively connected to the first terminal and each of the switching switches, and the controller is used to generate a temperature sampling value based on the electrical signal; and based on the temperature sampling value, output a first control signal to the switching switch, wherein the first control signal is used to switch the switching state of the switching switch to control the conduction state of the at least one voltage-dividing resistor.

[0012] In some embodiments, the multiple voltage-dividing resistors are arranged in series and / or in parallel between the first terminal and the first ground terminal; the multiple voltage-dividing resistors are controlled by the at least two switching switches so that the voltage-dividing module supports at least three grounding resistance values.

[0013] In some embodiments, the plurality of voltage-dividing resistors include at least two switchable voltage-dividing resistors and at least one fixed voltage-dividing resistor disposed between the first terminal and the first ground terminal;

[0014] The at least two switchable voltage-dividing resistors are sequentially connected in series to form a first resistor string, and the first resistor string and the at least one fixed voltage-dividing resistor are connected in parallel between the first terminal and the first ground terminal; or,

[0015] The at least two switchable voltage-dividing resistors and the at least one fixed voltage-dividing resistor are connected in series between the first terminal and the first ground terminal; or,

[0016] The at least two switchable voltage-dividing resistors and the at least one fixed voltage-dividing resistor are connected in parallel between the first terminal and the first ground terminal;

[0017] The at least two switching voltage-dividing resistors are partially or fully connected based on the control of the at least two switching switches.

[0018] In some embodiments, the at least two switchable voltage-dividing resistors include a first switchable voltage-dividing resistor and a second switchable voltage-dividing resistor, the at least one fixed voltage-dividing resistor includes a first fixed voltage-dividing resistor, and the at least two switchable switches include: a first switchable switch and a second switchable switch;

[0019] The first end of the first switching voltage-dividing resistor is connected to the first terminal, the second end of the first switching voltage-dividing resistor is connected to the first end of the second switching voltage-dividing resistor, and the first switching switch is arranged between the second end of the second switching voltage-dividing resistor and the first ground terminal;

[0020] A first end of the first fixed voltage-dividing resistor is connected to the first terminal, and a second end of the first fixed voltage-dividing resistor is connected to the first ground terminal;

[0021] The second switch is connected in parallel to two ends of the first switching voltage-dividing resistor or the second switching voltage-dividing resistor.

[0022] In some embodiments, each of the switching switches includes a control input terminal, the controller includes a switching terminal, and each of the control input terminals is connected to the switching terminal.

[0023] In some embodiments, the temperature sampling circuit further includes:

[0024] A voltage acquisition module, wherein the voltage acquisition module comprises a voltage acquisition circuit and a second ground terminal, wherein the voltage acquisition circuit is respectively connected to the first terminal, the controller and the second ground terminal, and is used for acquiring an electrical signal at the first terminal and sending the signal to the controller.

[0025] In some embodiments, the voltage acquisition circuit includes a voltage stabilizing circuit and an electrolytic capacitor, one end of the electrolytic capacitor is respectively connected to the first terminal and the first end of the voltage stabilizing circuit, and the other end of the electrolytic capacitor is respectively connected to the first ground terminal and the second end of the voltage stabilizing circuit;

[0026] The third terminal of the voltage stabilizing circuit is connected to the controller.

[0027] In some embodiments, the controller includes an analog-to-digital conversion terminal, and the analog-to-digital conversion terminal is used to perform analog-to-digital conversion on the electrical signal;

[0028] The controller is also used to generate a temperature sampling value based on the electrical signal after analog-to-digital conversion.

[0029] In some embodiments, the switching switch includes at least a relay, a triode or a silicon carbide field effect transistor.

[0030] In a second aspect, an embodiment of the present application provides an air conditioner, comprising the temperature sampling circuit as described in the first aspect above.

[0031] An embodiment of the present application provides a temperature sampling circuit, which includes: a thermistor element, a voltage divider module, at least two switching switches and a controller, the thermistor element, the first end of the thermistor element is connected to a power supply; the voltage divider module includes a first terminal, a first ground terminal and a plurality of voltage divider resistors arranged between the first terminal and the first ground terminal, the first terminal is connected to the second end of the thermistor element, and the first terminal is used to output an electrical signal representing a temperature change; each switching switch is correspondingly connected to at least one voltage divider resistor, and is used to switch the voltage divider ratio of the ground resistance value of the voltage divider module; the controller is respectively connected to the first terminal and each switching switch, and the controller is used to generate a temperature sampling value based on the electrical signal; and based on the temperature sampling value, outputs a first control signal to the switching switch, and the first control signal is used to switch the switch state of the switching switch to control the conduction state of at least one voltage divider resistor.

[0032] In this way, the embodiment of the present application introduces at least two switching switches, each of which can control the conduction state of at least one voltage-dividing resistor based on a first control signal, thereby making more accurate dynamic adjustments to the ground resistance of the voltage-dividing circuit within the entire temperature range, thereby expanding the range of the voltage-dividing ratio, and improving the accuracy of temperature sampling in the entire temperature range, providing conditions for precise temperature control of the machine, and further improving the energy efficiency and reliability of the machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A comparison table of resistance and temperature of a conventional exhaust pipe temperature sensor in the related art;

[0034] Figure 2 A schematic diagram of a module of a temperature sampling circuit provided in an embodiment of the present application;

[0035] Figure 3 A schematic diagram of a connection between a switchable voltage-dividing resistor and a fixed voltage-dividing resistor according to an embodiment of the present application;

[0036] Figure 4 It is another connection schematic diagram of the switchable voltage-dividing resistor and the fixed voltage-dividing resistor in the embodiment of the present application;

[0037] Figure 5 A schematic diagram of another connection structure of the switchable voltage-dividing resistor and the fixed voltage-dividing resistor according to an embodiment of the present application;

[0038] Figure 6 A schematic diagram of the structure of a temperature sampling circuit provided in an embodiment of the present application;

[0039] Figure 7 A schematic diagram of the circuit structure of a temperature sampling circuit in an application example of the present application;

[0040] Figure 8 Schematic diagram of the control flow of a temperature sampling circuit for a full temperature range in an application example of the present application.

[0041] Description of reference numerals:

[0042] 1. Power supply;

[0043] R1, thermistor element;

[0044] 2. voltage divider module; 21. first terminal; 22. first ground terminal; R2. voltage divider resistor; R21. switching voltage divider resistor; R211. first switching voltage divider resistor; R212. second switching voltage divider resistor; R22. fixed voltage divider resistor; R221. first fixed voltage divider resistor;

[0045] 3. Switch; 31. First switch; 32. Second switch; 33. Control input terminal; 331. First control input terminal; 332. Second control input terminal;

[0046] 4. Controller; 41. Switching terminal; 42. Analog-to-digital conversion terminal;

[0047] 5. Voltage acquisition module; 51. Voltage acquisition circuit; 52. Second ground terminal; 511. Voltage stabilizing circuit; E1. Electrolytic capacitor. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings. The described embodiments should not be regarded as limiting the present application. All other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application.

[0049] In the description of the present application, reference is made to “some embodiments”, which describe a subset of all possible embodiments, but it can be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0050] In the description of the present application, the terms "first, second" and the like are only used to distinguish similar objects and do not represent a specific order of the objects. It is understandable that "first, second" and the like can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. Unless otherwise specified, "plurality" means at least two.

[0051] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0052] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0053] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0054] In the related art, a temperature sensor is a device used to detect changes in ambient temperature, which can convert temperature into an electrical signal output. Temperature sensors include resistive temperature sensors, which include thermistors. Thermistors are resistors that are very sensitive to temperature changes, and their core feature is that their resistance value changes significantly with the rise and fall of ambient temperature. Thermistors include: negative temperature coefficient (NTC) thermistors. The resistance value of this type of thermistor decreases as the temperature rises. NTC thermistors are usually made of metal oxide semiconductor materials, such as a mixture of manganese, nickel, and cobalt oxides. Due to its high sensitivity to temperature, it is widely used in machines that require high sensitivity and wide temperature range measurement.

[0055] like Figure 1 As shown, Figure 1 This is a comparison table of resistance (K) and temperature (℃) of conventional exhaust pipe temperature sensors.

[0056] When the temperature is in the low temperature range, for example, the temperature is from -20°C to -19°C, the resistance: 511.39K (0.0778V) becomes 487.57K (0.0816V), and the voltage difference ΔV = 0.0816-0.0778 = 0.0037V.

[0057] When the temperature is in the medium temperature range, for example, the temperature is from 50°C to 51°C, the resistance changes from 20.931K (1.3938V) to 20.135K (1.433V), and the voltage difference ΔV=1.433-1.393=0.0425V.

[0058] When the temperature is in the high temperature range, for example, the temperature is from 125°C to 126°C, the resistance changes from 1.741K (4.114V) to 1.699K (4.1321V), and the voltage difference ΔV=4.132-4.114=0.0176V.

[0059] The above shows that the sensor has high resistance resolution in the medium temperature range, and very low resolution in the low and high temperature ranges.

[0060] As air-conditioning technology continues to expand, its application scope is becoming increasingly wide, but in specific scenarios such as kitchens, installing air conditioners still faces unique challenges. Currently, most kitchens do not have reserved holes for air-conditioning installation. Kitchen air conditioners can only be installed on the kitchen ceiling. Holes need to be drilled to exhaust the hot air generated by the air conditioner to the outside. Due to the load-bearing limit of the building, the holes cannot be too many or too large, which will cause the exhaust temperature of the air conditioner to be high. In this scenario, air conditioners using carbon dioxide as a refrigerant have more advantages than air conditioners using refrigerant as a refrigerant.

[0061] For air conditioners using CO2 as refrigerant, it is especially necessary to maintain high resolution in the high temperature range to achieve precise temperature control, improve energy efficiency, and provide protection in harsh low temperature environments. Figure 1 The temperature sensor in the air conditioner will not be able to make accurate control at the low temperature and high temperature sections.

[0062] Based on this, a temperature sampling circuit is proposed in this application. Please refer to Figure 2 The temperature sampling circuit includes: a power supply 1, a thermistor element R1, a voltage dividing module 2, at least two switching switches 3 and a controller 4.

[0063] Please refer to Figure 2 , a first end of the thermistor element R1 is connected to the power supply 1.

[0064] It is understandable that the power supply 1 is used to output a stable voltage source to the thermistor element R1, so that the thermistor element R1 can generate an electrical signal reflecting temperature changes. The first end of the thermistor element R1 is connected to the power supply 1, and the voltage value of the power supply 1 is generally 5V or 3.3V.

[0065] Please refer to Figure 2 The voltage divider module 2 includes a first terminal 21, a first ground terminal 22 and a plurality of voltage divider resistors R2 arranged between the first terminal 21 and the first ground terminal 22. The first terminal 21 is connected to the second end of the thermistor element R1. The first terminal 21 is used to output an electrical signal representing temperature changes, which is a voltage signal.

[0066] It is understandable that the second end of the thermistor element R1 is directly connected to the first terminal 21 of the voltage divider module 2. When the resistance value of the thermistor element R1 changes with temperature, the current flowing through the thermistor element R1 will also change accordingly, thereby causing the voltage on the first terminal 21 to change.

[0067] It is understandable that, due to the resistance change of thermistor element R1 in a certain temperature range (for example, high temperature section or low temperature section), it is not possible to accurately reflect the temperature in certain specific temperature sections, resulting in inaccurate changes in the electrical signal. Therefore, in order to ensure that the temperature sampling circuit can be applied to the full temperature range, the first end of the thermistor element R1 is connected to the voltage divider module 2, and the voltage divider module 2 includes a plurality of voltage divider resistors R2, and the plurality of voltage divider resistors R2 are arranged between the first terminal 21 and the first ground terminal 22. The electrical signal formed by the voltage division of the plurality of voltage divider resistors R2 can reflect the temperature change in the full temperature range.

[0068] In some embodiments, please refer to Figure 2 Each switch 3 is correspondingly connected to at least one voltage dividing resistor R2 and is used to switch the grounding resistance of the voltage dividing module 2 to control the voltage dividing ratio of the voltage dividing module 2 .

[0069] It can be understood that in order to further improve the flexibility of the temperature sampling circuit and ensure that it can have a high sampling accuracy in the entire temperature range, the temperature sampling circuit of the present application includes at least two switching switches 3, each switching switch 3 can be connected to a corresponding voltage dividing resistor R2, or each switching switch 3 can also be connected to multiple voltage dividing resistors R2.

[0070] When the switch 3 changes the switch state (open or close), it can determine which voltage dividing resistors R2 in the voltage dividing module 2 participate in the actual voltage dividing process and which are bypassed or short-circuited, thereby switching the grounding resistance from the first terminal 21 to the first grounding terminal 22.

[0071] It can be understood that the voltage divider module 2 distributes the voltage Vin applied by the power supply 1 to the two ends of the thermistor element R1 according to a certain ratio through multiple voltage divider resistors R2. This ratio is the voltage divider ratio. The voltage divider ratio of the voltage divider module 2 is the ratio of the voltage Vout of the first terminal 21 to Vin (Vout / Vin).

[0072] For example, during the voltage division process, the voltage value Vout finally output by the first terminal 21 can be determined based on the following formula:

[0073] Vout=Vin*(R2 / (R1+R2)

[0074] In the above formula, Vin is the voltage value of the power supply 1, R1 is the resistance from the power supply 1 to the voltage dividing point (i.e., the first terminal 21) (i.e., the resistance value of the thermistor element R1), and R2 (i.e., the grounding resistance value of the voltage dividing module 2) is the resistance from the voltage dividing point to the first ground terminal 22.

[0075] It is understandable that by changing the resistance value (i.e., the value of R2) from the voltage dividing point to the first ground terminal 22, the ratio of the output voltage (electrical signal) to the input voltage, i.e., the voltage dividing ratio, can be adjusted. In this way, the grounding resistance value of the voltage dividing circuit can be more accurately and dynamically adjusted in the full temperature range, thereby expanding the range of the voltage dividing ratio.

[0076] In some embodiments, the controller 4 is respectively connected to the first terminal 21 and each switching switch 3, and the controller 4 is used to generate a temperature sampling value based on the electrical signal; and based on the temperature sampling value, output a first control signal to the switching switch 3, and the first control signal is used to switch the switching state of the switching switch 3 to control the conduction state of at least one voltage-dividing resistor R2.

[0077] Here, the controller 4 pre-stores a mapping relationship, which represents the correspondence between each electrical signal and each temperature sampling value. The controller 4 receives the electrical signal from the first terminal 21, searches for the temperature sampling value corresponding to the electrical signal in the mapping relationship, and generates the temperature sampling value.

[0078] It can be understood that, based on the temperature sampling value, the controller 4 further outputs a first control signal to the switch 3 for switching the switch state of the switch 3 to control the conduction state of at least one voltage-dividing resistor R2.

[0079] It should be noted that, in order to improve the temperature sampling accuracy of the temperature sampling circuit in the entire temperature range, the controller 4 may generate the first control signal based on a plurality of temperature sampling intervals and temperature sampling values.

[0080] In some embodiments, the controller 4 may determine a target temperature sampling interval based on the temperature sampling value and a plurality of temperature sampling intervals; and generate a first control signal based on a target switching strategy corresponding to the target temperature sampling interval.

[0081] Exemplarily, the multiple temperature sampling intervals are divided into at least three temperature sampling intervals, namely a low temperature sampling interval, a medium temperature sampling interval and a high temperature sampling interval, and each temperature sampling interval has a corresponding switching strategy.

[0082] Assuming that the temperature sampling interval is within the high temperature sampling interval, the target sampling interval is determined to be the high temperature sampling interval, and a first control signal is generated based on a high temperature switching strategy corresponding to the high temperature sampling interval.

[0083] It is understandable that for thermistor element R1, the size of its resistance decreases as the temperature increases. Therefore, in order to maintain sampling accuracy, the grounding resistance corresponding to the low-temperature sampling interval is the largest, followed by the medium-temperature sampling interval, and the grounding resistance corresponding to the high-temperature sampling interval is the smallest. The switching strategy includes: a low-temperature switching strategy for adjusting the grounding resistance of the voltage divider module 2 to the maximum, a medium-temperature switching strategy for adjusting the grounding resistance of the voltage divider module 2 to a medium, and a high-temperature switching strategy for adjusting the grounding resistance of the voltage divider module 2 to the minimum.

[0084] Exemplarily, based on the high temperature switching strategy, a first control signal is generated, and the first control signal is used to switch the switching state of the switching switch 3 to control the conduction state of at least one voltage dividing resistor R2 to adjust the grounding resistance of the voltage dividing module 2 to the minimum.

[0085] The embodiment of the present application introduces at least two switching switches 3, each of which can control the conduction state of at least one voltage-dividing resistor R2 based on a first control signal, thereby making more accurate dynamic adjustments to the grounding resistance of the voltage-dividing circuit within the entire temperature range, thereby expanding the range of the voltage-dividing ratio, and improving the accuracy of temperature sampling in the entire temperature range, providing conditions for accurate temperature control of the machine, and further improving the energy efficiency and reliability of the machine.

[0086] In some embodiments, multiple voltage-dividing resistors R2 are arranged in series and / or in parallel between the first terminal 21 and the first ground terminal 22; the multiple voltage-dividing resistors R2 are controlled by at least two switching switches 3 so that the voltage-dividing module 2 supports at least three grounding resistance values.

[0087] Here, multiple voltage-dividing resistors R2 can be arranged in series and / or in parallel between the first terminal 21 and the first ground terminal 22. If multiple voltage-dividing resistors R2 are arranged in series between the first terminal 21 and the first ground terminal 22, the total resistance of the entire voltage-dividing circuit can be changed by changing the number of series resistors, thereby affecting the grounding resistance. If parallel connection is adopted, since the total resistance in the parallel circuit will be less than the resistance of any parallel branch resistor, the grounding resistance can also be adjusted by adjusting the combination of parallel resistors.

[0088] Here, since the full temperature range is divided into at least a low temperature range, a medium temperature range and a high temperature range, the voltage divider module 2 in the present application is controlled by at least two switching switches 3, so that the voltage divider module 2 supports at least three grounding resistance values, thereby improving the temperature sampling accuracy of the full temperature range, realizing accurate temperature control of the machine, and improving the energy efficiency of the machine.

[0089] In some embodiments, the plurality of voltage-dividing resistors R2 include at least two switchable voltage-dividing resistors R21 and at least one fixed voltage-dividing resistor R22 disposed between the first terminal 21 and the first ground terminal 22 .

[0090] Here, in order to save the number of switching switches 3, the multiple voltage-dividing resistors R2 of the temperature sampling circuit include a switching voltage-dividing resistor R21 and a fixed voltage-dividing resistor R22.

[0091] It can be understood that for the switching voltage-dividing resistors R21, whether they are connected to the circuit is variable and controlled by at least two switching switches 3. At least two switching voltage-dividing resistors R21 are partially or fully connected based on the control of at least two switching switches 3, thereby changing the grounding resistance of the entire voltage-dividing module 2.

[0092] It should be noted that the fixed voltage-dividing resistor R22 is opposite to the switching voltage-dividing resistor R21, and the fixed voltage-dividing resistor R22 is always connected in the circuit, its resistance value remains unchanged, and it is not connected to the switching switch 3. In the embodiment of the present application, the fixed voltage-dividing resistor R22 provides a basic resistance reference for the voltage-dividing module 2, ensuring that no matter how the switching voltage-dividing resistor R21 is configured, there is always a certain minimum resistance value, thereby ensuring the stability and reliability of the temperature sampling circuit.

[0093] It can be understood that, since the number of the switching switches 3 is at least two, the number of the switching voltage-dividing resistors R21 is at least two, and the number of the fixed voltage-dividing resistors R22 is at least one.

[0094] In one embodiment, at least two switchable voltage-dividing resistors R21 are sequentially connected in series to form a first resistor string, and the first resistor string and at least one fixed voltage-dividing resistor R22 are connected in parallel between the first terminal 21 and the first ground terminal 22 .

[0095] For example, please refer to Figure 3 The switching resistor R2 includes at least two switching voltage-dividing resistors R21, and the at least two switching resistors R21 include R211, ..., R21n. R211, ..., R21n are sequentially connected in series to form a first resistor string, and the first resistor string is connected in parallel with at least one fixed resistor R22 between the first terminal 21 and the first ground terminal 22.

[0096] In another embodiment of the present invention, at least two switchable voltage-dividing resistors R21 and at least one fixed voltage-dividing resistor R22 are connected in series between the first terminal 21 and the first ground terminal 22 .

[0097] For example, please refer to Figure 4 The switch resistor R2 includes at least two switch voltage divider resistors R21, and the at least two switch resistors R21 include R211, ..., R21n. R211, ..., R21n and at least one fixed resistor R22 are connected in series between the first terminal 21 and the first ground terminal 22.

[0098] In another embodiment of the present invention, at least two switchable voltage-dividing resistors R21 and at least one fixed voltage-dividing resistor R22 are connected in parallel between the first terminal 21 and the first ground terminal 22 .

[0099] For example, please refer to Figure 5 The switching resistor R2 includes at least two switching voltage-dividing resistors R21, and the at least two switching resistors R21 include R211, ..., R21n. R211, ..., R21n and at least one fixed resistor R22 are connected in parallel between the first terminal 21 and the first ground terminal 22.

[0100] For further information, please refer to Figure 6 In some embodiments, at least two switching voltage-dividing resistors R21 include a first switching voltage-dividing resistor R211 and a second switching voltage-dividing resistor R212, at least one fixed voltage-dividing resistor R22 includes a first fixed voltage-dividing resistor R221, and at least two switching switches 3 include: a first switching switch 31 and a second switching switch 32.

[0101] Here, please refer to Figure 6 A first end of the first switching voltage-dividing resistor R211 is connected to the first terminal 21 , and a second end of the first switching voltage-dividing resistor R211 is connected to a first end of the second switching voltage-dividing resistor R212 .

[0102] Here, a first switch 31 is disposed between the second end of the second switching voltage-dividing resistor R212 and the first grounding end 22 .

[0103] Here, please refer to Figure 6 A first end of the first fixed voltage-dividing resistor R221 is connected to the first terminal 21 , and a second end of the first fixed voltage-dividing resistor R221 is connected to the first ground terminal 22 .

[0104] It is understandable that, taking the air conditioner as an example, in order to ensure that when the air conditioner is powered on, no matter how the voltage-dividing resistor R21 is configured, there is always a certain minimum resistance value, thereby ensuring the stability and reliability of the temperature sampling circuit. When the power is just turned on, the first switch 31 and the second switch 32 are both controlled to be in the off state, ensuring that only the first fixed resistor R221 and the thermistor element R1 are used for voltage division.

[0105] In some embodiments, the second switch 32 is connected in parallel to both ends of the first switching voltage-dividing resistor R211 or the second switching voltage-dividing resistor R212 .

[0106] In some embodiments, please refer to Figure 6 , the second switch 32 is connected in parallel with both ends of the first switching voltage-dividing resistor R211.

[0107] In some embodiments, Figure 3As shown, each switch 3 includes a control input terminal 33 , and the controller 4 includes a switching terminal 41 . Each control input terminal 33 is connected to the switching terminal 41 .

[0108] For example, in Figure 6 In the embodiment, the first switch 31 includes a first control input terminal 331 , the second switch 32 includes a second control input terminal 332 , and the controller 4 includes a switch terminal 41 ; the first control input terminal 331 and the second control input terminal 332 are respectively connected to the switch terminal 41 .

[0109] It can be understood that if it is determined that the temperature sampling value is within the low temperature sampling interval, the low temperature switching strategy corresponding to the low temperature sampling interval is: the first switching switch 31 and the second switching switch 32 are both disconnected, and the resistance value of the first fixed voltage-dividing resistor R221 and the resistance value of the thermistor element R1 are used for voltage division. Based on the low temperature switching strategy, a first control signal is generated, and the first control signal includes a first switching signal indicating that the first switching switch 31 is disconnected and a second switching signal indicating that the second switching switch 32 is disconnected. The controller 4 sends a first switching signal to the first switching switch 31 based on the first control input terminal 331 via the switching terminal 41; the controller 4 sends a second switching signal to the second switching switch 32 based on the second control input terminal 332 via the switching terminal 41.

[0110] It can be understood that if it is determined that the temperature sampling value is within the medium temperature sampling interval, the medium temperature switching strategy corresponding to the medium temperature sampling interval is: the first switching switch 31 is closed and the second switching switch 32 is disconnected. The first switching voltage-dividing resistor R211 and the second switching voltage-dividing resistor R212 are connected in series with the parallel resistance of the first fixed voltage-dividing resistor R221 and the resistance of thermistor 1 to divide the voltage. Based on the medium temperature switching strategy, a first control signal is generated, and the first control signal includes a first switching signal indicating that the first switching switch 31 is closed and a second switching signal indicating that the second switching switch 32 is disconnected. The controller 4 sends a first switching signal to the first switching switch 31 based on the first control input terminal 331 via the switching terminal 41; the controller 4 sends a second switching signal to the second switching switch 32 based on the second control input terminal 332 via the switching terminal 41.

[0111] It can be understood that if it is determined that the temperature sampling value is within the high temperature sampling interval, the high temperature switching strategy corresponding to the high temperature sampling interval is: the first switching switch 31 is closed and the second switching switch 32 is closed. The voltage is divided by the parallel resistance of the second switching voltage-dividing resistor R212 and the first fixed voltage-dividing resistor R221 and the resistance of the thermistor element R1. Based on the high temperature switching strategy, a first control signal is generated, and the first control signal includes a first switching signal indicating that the first switching switch 31 is closed and a second switching signal indicating that the second switching switch 32 is closed. The controller 4 sends a first switching signal to the first switching switch 31 based on the first control input terminal 331 via the switching terminal 41; the controller 4 sends a second switching signal to the second switching switch 32 based on the second control input terminal 332 via the switching terminal 41.

[0112] In some implementations, see Figure 2 and Figure 6 , the temperature sampling circuit also includes:

[0113] The voltage acquisition module 5 includes a voltage acquisition circuit 51 and a second ground terminal 52 . The voltage acquisition module 51 is respectively connected to the first terminal 21 , the controller 4 and the second ground terminal 52 , and is used to acquire the electrical signal at the first terminal 21 and send it to the controller 4 .

[0114] In some embodiments, please refer to Figure 7 The voltage acquisition circuit 51 includes a voltage stabilizing circuit 511 and an electrolytic capacitor E1, one end of the electrolytic capacitor E1 is respectively connected to the first terminal 21 and the first end of the voltage stabilizing circuit 511, and the other end of the electrolytic capacitor 52 is respectively connected to the second ground terminal 52 and the second end of the voltage stabilizing circuit 511; the third end of the voltage stabilizing circuit 511 is connected to the controller 4.

[0115] In some embodiments, the controller 4 includes an analog-to-digital conversion terminal 42, and the analog-to-digital conversion terminal 42 is used to perform analog-to-digital conversion on the electrical signal; the controller 4 is also used to generate a temperature sampling value based on the analog-to-digital converted electrical signal.

[0116] It is understandable that the temperature sampling output is usually an analog voltage signal. During data processing, the controller 4 needs to perform analog-to-digital conversion on the analog voltage signal to convert it into a digital signal. The controller 4 is also used to generate a temperature sampling value based on the analog-to-digital converted electrical signal and a preset mapping relationship.

[0117] In some embodiments, the switch 3 at least includes a relay, a triode or a silicon carbide field effect transistor.

[0118] The embodiment of the present application is described in detail below with reference to an application example.

[0119] This application example provides a CO2 refrigerant air conditioner and a temperature sampling method thereof, aiming to enable the air conditioner using CO2 as the refrigerant to accurately read the temperature value in the entire temperature range, thereby achieving accurate control and further improving energy efficiency.

[0120] This application example provides a schematic diagram of the structure of a temperature sampling circuit. Figure 7 As shown, the main components include: a thermistor element R1, a power supply 1, a first terminal 21, a first ground terminal 22, a first switching switch 31, a second switching switch 32, a first switching voltage-dividing resistor R211, a second switching voltage-dividing resistor R212, a first fixed voltage-dividing resistor R221, and a voltage acquisition circuit 51.

[0121] Here, the power supply 1 is generally 5V or 3.3V, the thermistor element R1 is a resistive temperature sensor, and the switch 3 can be a MOS tube, a triode or a relay. The voltage acquisition circuit 51 is connected to the AD input pin 42 of the MCU (controller 4).

[0122] In this application example, the power supply 1 is 5V, and the switch 3 is a MOS tube. The resistor R3 and the capacitor C1 form a voltage stabilizing circuit 511, and the voltage acquisition circuit 51 includes the voltage stabilizing circuit 511 and the electrolytic capacitor E1.

[0123] like Figure 7 As shown, the switch 3 includes a first MOS transistor Q1 and a second MOS transistor Q2, the first MOS transistor Q1 includes a control input terminal G1, the second MOS transistor Q2 includes a control input terminal G2, and the controller 4 includes a switching terminal 41; the control input terminal G1 of the first MOS transistor Q1 and the control input terminal G2 of the first MOS transistor Q1 are respectively connected to the switching terminal 41.

[0124] In this application example, the first switching voltage-dividing resistor R211, the second switching voltage-dividing resistor R212 and the first fixed voltage-dividing resistor R221 have different resistance values, and the combination of the three can be series connection, parallel connection, or multiple combinations of series and parallel connection.

[0125] like Figure 7 As shown, Figure 7A connection method of the first switching voltage-dividing resistor R211, the second switching voltage-dividing resistor R212, and the first fixed voltage-dividing resistor R221 is shown. The first end of the first switching voltage-dividing resistor R211 is connected to the first terminal 21, the second end of the first switching voltage-dividing resistor R211 is connected to the first end of the second switching voltage-dividing resistor R212, and the first switching switch 31 is arranged between the second end of the second switching voltage-dividing resistor R212 and the ground terminal GND; the first end of the first fixed voltage-dividing resistor R221 is connected to the first terminal 21, and the second end of the first fixed voltage-dividing resistor R221 is connected to the ground terminal GND; the second switching switch 32 is connected in parallel with the two ends of the first switching voltage-dividing resistor R211.

[0126] In this way, this application example is based on the above structure and uses two switches to form three different resistance values, which reduces the cost of the temperature sampling circuit. At the same time, by controlling the switch, any resistance combination can be made, and different temperature segments use different reference resistors for voltage division to read the temperature value, thereby improving the resolution and accuracy of each temperature segment, providing conditions for precise temperature control of the machine, and further improving the energy efficiency and reliability of the system.

[0127] In actual applications, there are three independent algorithms in the system, so that any combination of resistors can read the temperature value and determine which temperature segment the current temperature belongs to. The controller divides the temperature segment into three parts in advance: low temperature segment (-40℃~0℃), medium temperature segment (1℃~100℃), and high temperature segment (101℃~140℃). And set a corresponding control scheme for each temperature segment to control the switching state of the switching switch 3 and the conduction state of each reference resistor. When the temperature changes from one temperature segment to another, the corresponding control is also executed. For example: when the temperature changes from 100℃ to 101℃, the system will immediately switch to the control logic of the high temperature segment. The first switching switch 31 is closed and the second switching switch 32 is closed. Changes in other temperature segments are analogous.

[0128] Figure 8 This is a control flow diagram of the temperature acquisition circuit for the full temperature range. Figure 8 , the full temperature control scheme is described in detail. The control scheme includes the following steps:

[0129] Step 801: When the power is just turned on, the first MOS tube Q1 and the second MOS tube Q2 are disconnected, the system defaults to the low temperature segment logic, and reads the temperature sampling value T.

[0130] In this application example, the control scheme for the low temperature section is to disconnect the first MOS transistor Q1 and the second MOS transistor Q2, and divide the voltage by the resistance of the first fixed voltage-dividing resistor R221 and the resistance of the temperature sensor R1.

[0131] Here, when the air conditioner is powered on, to ensure the stability and reliability of the temperature sampling circuit, first control the first MOS transistor Q1 and the second MOS transistor Q2 to disconnect, and then start reading the temperature sampling value T based on the temperature sampling circuit.

[0132] Next, corresponding control logic can be executed based on the temperature range in which the temperature sampling value T falls. For example, the control logic in the low-temperature range corresponds to the following steps 802 to 803, the control logic in the medium-temperature range corresponds to the following steps 804 to 805, and the control logic in the high-temperature range corresponds to the following steps 806 to 807. And so on in a loop to achieve precise control of temperature sampling in the entire temperature range.

[0133] Step 802: Determine that the temperature is in the low-temperature range, and execute step 803.

[0134] Here, if it is determined whether the temperature sampling value is within the range of -40°C < T <= 0°C, if so, determine that the temperature is in the low-temperature range, and then execute step 803.

[0135] Step 803: Disconnect the first MOS transistor Q1 and the second MOS transistor Q2, and perform voltage division with the resistance value of the first fixed voltage-dividing resistor R221 and the resistance value of the temperature sensor R1.

[0136] In practical applications, if after power-on, it is detected that the temperature sampling value T is within the range of -40°C < T <= 0°C, since the control logic at power-on is the same as the low-temperature control logic, there is no need to switch at this time.

[0137] Step 804: Determine that the temperature is in the medium-temperature range, and execute step 805.

[0138] Here, if it is determined whether the temperature sampling value is within the range of 0°C < T <= 100°C, if so, determine that the temperature is in the medium-temperature range, and then execute step 805.

[0139] Step 805: Close the first MOS transistor Q1 and disconnect the second MOS transistor Q2; perform voltage division with the resistance value obtained by connecting the first switching voltage-dividing resistor 211 and the second switching voltage-dividing resistor R212 in series and then connecting them in parallel with the first fixed voltage-dividing resistor R221.

[0140] Here, the first MOS transistor Q1 is closed, the second MOS transistor Q2 is disconnected, and the first switching voltage-dividing resistor 211 and the second switching voltage-dividing resistor R212 are connected in series and then connected in parallel with the first fixed voltage-dividing resistor R221.

[0141] Step 806: Determine that the temperature is in the high-temperature range, and execute step 807.

[0142] Here, if it is determined whether the temperature sampling value is within the range of 100°C < T <= 140°C, if so, determine that the temperature is in the high-temperature range, and then execute step 807.

[0143] Step 807: the first MOS transistor Q1 is turned on, and the second MOS transistor Q2 is turned on; and voltage is divided by the resistance value of the second switching voltage-dividing resistor R212 and the first fixed voltage-dividing resistor R221 connected in parallel.

[0144] Here, when the first MOS transistor Q1 is energized, the MOS transistor Q1 is turned on, and when the second MOS transistor Q2 is energized, the second MOS transistor Q2 is turned on, and the second switching voltage-dividing resistor R212 is connected in parallel with the first fixed voltage-dividing resistor R221.

[0145] This application example divides the full temperature range into three temperature ranges. Different temperature ranges use different reference resistors for voltage division to read the temperature value, which improves the resolution and accuracy of each temperature range, provides conditions for precise temperature control of the machine, and further improves the energy efficiency and reliability of the system. At the same time, the two switches are reasonably used to combine three resistance values, reducing costs.

[0146] An embodiment of the present application also provides an air conditioner, comprising the above-mentioned temperature sampling circuit.

[0147] It should be noted that the technical solutions described in the embodiments of the present application can be combined arbitrarily without conflict.

[0148] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A temperature sampling circuit, characterized in that: The temperature sampling circuit comprises: A thermistor element, wherein a first end of the thermistor element is connected to a power supply; A voltage dividing module, the voltage dividing module comprising a first terminal, a first ground terminal and a plurality of voltage dividing resistors arranged between the first terminal and the first ground terminal, the first terminal being connected to the second end of the thermistor element, and the first terminal being used to output an electrical signal representing a temperature change; At least two switching switches, each of which is connected to at least one voltage-dividing resistor and is used to switch the grounding resistance of the voltage-dividing module to control the voltage-dividing ratio of the voltage-dividing module; A controller, wherein the controller is respectively connected to the first terminal and each of the switching switches, and the controller is used to generate a temperature sampling value based on the electrical signal; and based on the temperature sampling value, output a first control signal to the switching switch, wherein the first control signal is used to switch the switching state of the switching switch to control the conduction state of the at least one voltage-dividing resistor.

2. The temperature sampling circuit according to claim 1, characterized in that: The multiple voltage-dividing resistors are arranged in series and / or in parallel between the first terminal and the first ground terminal; the multiple voltage-dividing resistors are controlled by the at least two switching switches so that the voltage-dividing module supports at least three grounding resistance values.

3. The temperature sampling circuit according to claim 2, characterized in that: The plurality of voltage-dividing resistors include at least two switching voltage-dividing resistors and at least one fixed voltage-dividing resistor disposed between the first terminal and the first ground terminal; The at least two switchable voltage-dividing resistors are sequentially connected in series to form a first resistor string, and the first resistor string and the at least one fixed voltage-dividing resistor are connected in parallel between the first terminal and the first ground terminal; or, The at least two switchable voltage-dividing resistors and the at least one fixed voltage-dividing resistor are connected in series between the first terminal and the first ground terminal; or, The at least two switchable voltage-dividing resistors and the at least one fixed voltage-dividing resistor are connected in parallel between the first terminal and the first ground terminal; The at least two switching voltage-dividing resistors are partially or fully connected based on the control of the at least two switching switches.

4. The temperature sampling circuit according to claim 3, characterized in that: The at least two switchable voltage-dividing resistors include a first switchable voltage-dividing resistor and a second switchable voltage-dividing resistor, the at least one fixed voltage-dividing resistor includes a first fixed voltage-dividing resistor, and the at least two switchable switches include a first switchable switch and a second switchable switch; The first end of the first switching voltage-dividing resistor is connected to the first terminal, the second end of the first switching voltage-dividing resistor is connected to the first end of the second switching voltage-dividing resistor, and the first switching switch is arranged between the second end of the second switching voltage-dividing resistor and the first ground terminal; A first end of the first fixed voltage-dividing resistor is connected to the first terminal, and a second end of the first fixed voltage-dividing resistor is connected to the first ground terminal; The second switch is connected in parallel to two ends of the first switching voltage-dividing resistor or the second switching voltage-dividing resistor.

5. The temperature sampling circuit according to claim 1, characterized in that: Each of the switching switches includes a control input terminal, the controller includes a switching terminal, and each of the control input terminals is connected to the switching terminal.

6. The temperature sampling circuit according to claim 1, characterized in that: The temperature sampling circuit also includes: A voltage acquisition module, wherein the voltage acquisition module comprises a voltage acquisition circuit and a second ground terminal, wherein the voltage acquisition circuit is respectively connected to the first terminal, the controller and the second ground terminal, and is used for acquiring an electrical signal at the first terminal and sending the signal to the controller.

7. The temperature sampling circuit according to claim 6, characterized in that: The voltage acquisition circuit includes a voltage stabilizing circuit and an electrolytic capacitor, one end of the electrolytic capacitor is respectively connected to the first terminal and the first end of the voltage stabilizing circuit, and the other end of the electrolytic capacitor is respectively connected to the first ground terminal and the second end of the voltage stabilizing circuit; The third terminal of the voltage stabilizing circuit is connected to the controller.

8. The temperature sampling circuit according to claim 6, characterized in that: The controller comprises an analog-to-digital conversion terminal, and the analog-to-digital conversion terminal is used to perform analog-to-digital conversion on the electrical signal; The controller is also used to generate a temperature sampling value based on the electrical signal after analog-to-digital conversion.

9. The temperature sampling circuit according to claim 1, characterized in that: The switch at least includes a relay, a triode or a silicon carbide field effect transistor.

10. An air conditioner, characterized in that: The method comprises the temperature sampling circuit as claimed in any one of claims 1 to 9.

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