Temperature sensing circuit and chip

Abstract

The embodiment of the application provides a temperature sensing circuit and a chip, wherein the circuit comprises a temperature sensing module, a sampling amplification module and an analog-to-digital conversion module; the control end of the temperature sensing module is connected with a first control signal, and the output end is connected with the input end of the sampling amplification module; the output end of the sampling amplification module is connected with the first input end of the analog-to-digital conversion module, and the control end is connected with a second control signal; the second input end of the analog-to-digital conversion module is connected with a reference voltage signal, and the control end is connected with a third control signal. The temperature sensing module performs dynamic element matching based on the first control signal, and outputs a temperature sensing signal; the sampling amplification module performs integral sampling on the temperature sensing signal based on the second control signal, and outputs a sampling signal after the dynamic element matching ends; and the analog-to-digital conversion module performs sampling quantization on the sampling signal based on the third control signal and the reference voltage signal, and outputs a temperature quantization signal. Through the above circuit, the temperature sensing circuit error can be effectively eliminated, and the measurement precision is improved.

Description

Technical Field

[0001] This application relates to the field of sensor technology, and in particular to a temperature sensing circuit and chip. Background Technology

[0002] As a fundamental sensing device, the accuracy of temperature sensors directly affects the performance of temperature measurement and control systems. Currently, the core sensing circuit of a traditional temperature sensor (hereinafter referred to as the temperature sensing circuit) generally includes five basic components: a temperature sensing module, a programmable gain amplifier (PGA), an analog-to-digital converter (ADC), an ADC reference generation circuit, and a bandgap reference circuit (BG). Each of these components can introduce varying degrees of error, affecting the accuracy of the temperature sensing circuit.

[0003] Current solutions improve the accuracy of temperature sensing circuits by modifying certain circuit designs to suppress or eliminate introduced errors. However, existing solutions still fail to effectively address the errors introduced in multiple stages of the temperature sensing process, making it difficult to meet the demands of high-precision applications.

[0004] Currently, there is no effective solution to the problem that the current error elimination methods for temperature sensing circuits are complex, ineffective, and have low measurement accuracy. Summary of the Invention

[0005] The purpose of this specification is to provide a temperature sensing circuit and chip to solve the problems that current temperature sensing circuits have complex error elimination methods that cannot effectively eliminate errors and have low measurement accuracy.

[0006] To solve the above-mentioned technical problems, this specification provides a temperature sensing circuit in a first aspect, comprising: a temperature sensing module, a sampling amplification module, and an analog-to-digital conversion module; wherein, the control terminal of the temperature sensing module is connected to a first control signal, the output terminal of the temperature sensing module is connected to the input terminal of the sampling amplification module, the output terminal of the sampling amplification module is connected to a first input terminal of the analog-to-digital conversion module, the control terminal of the sampling amplification module is connected to a second control signal, the second input terminal of the analog-to-digital conversion module is connected to a reference voltage signal, and the control terminal of the analog-to-digital conversion module is connected to a third control signal;

[0007] The temperature sensing module is used to perform dynamic component matching based on the first control signal and output a temperature sensing signal;

[0008] The sampling amplification module is used to perform integral sampling on the output of the temperature sensing module based on the second control signal, and output the sampling signal after the dynamic element matching is completed;

[0009] The analog-to-digital conversion module is used to sample and quantize the sampled signal based on the third control signal and the reference voltage signal, and output a temperature quantization signal.

[0010] In some embodiments of this specification, the first control signal, the second control signal, and the third control signal all include a first level and a second level;

[0011] The temperature sensing module is used to perform dynamic component matching when the level of the first control signal changes;

[0012] The sampling amplification module performs integral sampling on the output of the temperature sensing module when the second control signal is at the first level;

[0013] The analog-to-digital conversion module performs sampling and quantization on the sampled signal when the third control signal is at the first level.

[0014] In some embodiments of this specification, the first time period corresponding to each segment of the first level of the second control signal can cover the time of each level change of the first control signal, and the second time period corresponding to the first level of the third control signal is matched with the third time period corresponding to the first control signal being at the second level and the second control signal being at the first level.

[0015] In some embodiments of this specification, the temperature sensing module includes multiple current mirrors, a switching network, a first transistor, and a second transistor. The switching network includes a first switch and a second switch corresponding to each current mirror, and a third switch and a fourth switch corresponding to each transistor.

[0016] The input terminals of the plurality of current mirrors are connected in parallel to the power supply, the first terminal of each first switch is connected to the output terminal of the corresponding current mirror, and the second terminals of the plurality of first switches are connected in parallel to the first terminal of the third switch corresponding to the first transistor and the first terminal of the fourth switch corresponding to the second transistor.

[0017] The first terminal of each second switch is connected to the output terminal of the corresponding current mirror. The second terminals of multiple second switches are connected in parallel and connected to the first terminal of the third switch corresponding to the second transistor and the first terminal of the fourth switch corresponding to the first transistor.

[0018] The second terminals of the third and fourth switches corresponding to the first transistor are connected to the first electrode of the first transistor, and the second terminals of the third and fourth switches corresponding to the second transistor are connected to the first stage of the second transistor.

[0019] The control electrode and the second electrode of the first transistor, as well as the control electrode and the second electrode of the second transistor, are grounded;

[0020] The second terminals of the plurality of first switches are connected in parallel and then connected to the first input terminal of the sampling amplification module. The second terminals of the plurality of second switches are connected in parallel and then connected to the second input terminal of the sampling amplification module.

[0021] In some embodiments of this specification, the sampling amplification module includes an operational amplifier, two sampling capacitors, and two feedback capacitors;

[0022] The first end of each sampling capacitor is connected to an input terminal of an operational amplifier, and the second end of each sampling capacitor is connected to an output terminal of a temperature sensing module through a fifth switch. A first node is provided between the second end of each sampling capacitor and the fifth switch, and each first node is connected to one end of a sixth switch.

[0023] Each sampling capacitor is connected to a second node between itself and the input terminal of the operational amplifier. Each second node is connected to an output terminal of the operational amplifier through a fifth switch. Each second node is connected to a reset signal through a feedback capacitor and a seventh switch.

[0024] Each feedback capacitor is connected to a third node between itself and the seventh switch, and each third node is connected to an output terminal of the operational amplifier through a sixth switch.

[0025] The fifth switch, the sixth switch, and the seventh switch are connected to the second control signal.

[0026] In some embodiments of this specification, the second control signal includes a first sub-signal, a second sub-signal, and a third sub-signal, each sub-signal corresponding to controlling the on / off state of the fifth switch, the sixth switch, and the seventh switch, respectively.

[0027] In some embodiments of this specification, the sampling amplification module operates as follows:

[0028] Before the operational amplifier performs its first sampling, the seventh switch controls the feedback capacitor to reset according to the reset signal based on the second control signal.

[0029] The fifth switch, based on the second control signal, controls the operational amplifier to sample the output of the temperature sensing module once, and stores the offset of the operational amplifier in the feedback capacitor;

[0030] The sixth switch, based on the second control signal, controls the output of the operational amplifier to perform an integral sampling once, and transmits the corresponding output to the feedback capacitor for storage.

[0031] After the dynamic element matching is completed, the sixth switch controls the operational amplifier to output a sampling signal based on the second control signal.

[0032] In some embodiments of this specification, the sampling signal includes a first sampling sub-signal and a second sampling sub-signal;

[0033] The third control signal includes a sampling control sub-signal and a switching control sub-signal. The sampling control sub-signal is used to sample the output of the sampling amplification module, and the switching control sub-signal is used to switch the first sampling sub-signal and the second sampling sub-signal output by the sampling amplification module.

[0034] In some embodiments of this specification, the sampling amplification module includes a first output terminal and a second output terminal; the analog-to-digital conversion module includes a first input terminal, which includes a first sub-input terminal and a second sub-input terminal.

[0035] The first control terminal of the sampling amplification module is connected to the sampling control sub-signal, and the second control terminal of the sampling amplification module is connected to the switching control sub-signal;

[0036] The first and second sub-input terminals of the analog-to-digital converter module can be connected to the first and second output terminals of the sampling amplification module, respectively, under the control of the switching control sub-signal accessed by the second control terminal, or to the second and first output terminals of the sampling amplification module, respectively; and the analog-to-digital converter module can sample the sampling sub-signals accessed by the two sub-input terminals under the control of the sampling control sub-signal accessed by the first control terminal.

[0037] In some embodiments of this specification, the analog-to-digital conversion module includes a switch submodule consisting of multiple switches and an analog-to-digital converter. The switch submodule is connected to the output terminal of the sampling amplification module and the input terminal of the analog-to-digital converter. The control terminal of the switch submodule is connected to the switching control sub-signal, and the control terminal of the analog-to-digital converter is connected to the sampling control sub-signal.

[0038] Under the control of the switching control sub-signal, the switching sub-module can make the following: the first output terminal and the second output terminal of the sampling amplification module are respectively connected to the first sub-input terminal and the second sub-input terminal of the analog-to-digital converter, or the first output terminal and the second output terminal of the sampling amplification module are respectively connected to the second sub-input terminal and the first sub-input terminal of the analog-to-digital converter.

[0039] The analog-to-digital converter (ADC) is capable of sampling the sampling sub-signals of the two sub-input terminals connected to the ADC under the control of the sampling control sub-signal.

[0040] In some embodiments of this specification, the temperature sensing circuit further includes a reference generation circuit and a bandgap reference circuit. The output terminal of the bandgap reference circuit is connected to the input terminal of the reference generation circuit, and the output terminal of the reference generation circuit is connected to the second input terminal of the analog-to-digital conversion module.

[0041] In some embodiments of this specification, a fourth control signal is connected to the two input terminals of the bandgap reference circuit and / or the two input terminals of the reference generation circuit. The fourth control signal is used to perform an exchange operation on the two input signals of the bandgap reference circuit and / or the two input signals of the reference generation circuit.

[0042] The second aspect of this specification also provides a chip, including: the temperature sensing circuit described in the first aspect above and a processing unit, wherein the processing unit is connected to the output terminal of the analog-to-digital conversion module of the temperature sensing circuit, the processing unit is used to receive the temperature quantization signal output by the analog-to-digital conversion module, and determine the temperature output result based on at least two consecutive received temperature quantization signals, the temperature output result being used to characterize the temperature signal sensed by the temperature sensing circuit.

[0043] In some embodiments of this specification, the processing unit is communicatively connected to the control terminal of at least one of the temperature sensing module, sampling amplification module, or analog-to-digital conversion module of the temperature sensing circuit, and the processing unit is used to output corresponding control signals to the control terminals of each module.

[0044] In some embodiments of this specification, when the processing unit detects a preset error elimination trigger event, it outputs a corresponding control signal to the control terminals of each module of the temperature sensing circuit; or,

[0045] When the processing unit detects a preset error elimination stop event, it stops outputting corresponding control signals to the control terminals of each module of the temperature sensing circuit.

[0046] In some embodiments of this specification, the processing unit is provided with at least one register, which corresponds to at least one of the temperature sensing module, sampling amplification module, or analog-to-digital conversion module of the temperature sensing circuit. The value of the register is used to control the on / off state of the control signal output by the processing unit to the corresponding module of the temperature sensing circuit.

[0047] The temperature sensing circuit and chip provided in the embodiments of this specification, through the configuration of a temperature sensing module, a sampling amplification module, and an analog-to-digital conversion module, wherein the control terminal of the temperature sensing module is connected to a first control signal, the output terminal of the temperature sensing module is connected to the input terminal of the sampling amplification module, the output terminal of the sampling amplification module is connected to the first input terminal of the analog-to-digital conversion module, the control terminal of the sampling amplification module is connected to a second control signal, the second input terminal of the analog-to-digital conversion module is connected to a reference voltage signal, and the control terminal of the analog-to-digital conversion module is connected to a third control signal. Furthermore, the temperature sensing module can perform dynamic component matching based on the first control signal and output a temperature sensing signal; the sampling amplification module can perform integral sampling of the output of the temperature sensing module based on the second control signal and output a sampled signal after the dynamic component matching is completed; the analog-to-digital conversion module can perform sampling quantization of the sampled signal based on the third control signal and the reference voltage signal and output a quantized temperature signal. Through the temperature sensing circuit described above, the DEM of the temperature sensing module can be realized by controlling the first control signal. The combination of the first and second control signals can realize the integration sampling of the sampling amplification module at the same time as the DEM. Furthermore, on the basis of eliminating the mismatch error caused by the mismatch of internal components of the temperature sensing module, the operational amplifier offset of the sampling amplification module can be eliminated by storing the offset during the integration sampling process, thereby further improving the accuracy of the temperature sensing circuit. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 The diagram shown is a schematic of a temperature sensing circuit provided in an embodiment of this specification.

[0050] Figure 2 The diagram shown is a schematic of a temperature sensing circuit provided in an embodiment of this specification.

[0051] Figure 3 The diagram shown is a schematic of a temperature sensing circuit provided in an embodiment of this specification.

[0052] Figure 4 The diagram shown is a schematic of a sampling amplification module provided in an embodiment of this specification;

[0053] Figure 5 The diagram shown is a schematic of the operating timing of the sampling amplification module provided in the embodiment of this specification;

[0054] Figure 6The diagram shown is a schematic of the operating timing of the temperature sensing circuit provided in the embodiment of this specification. Detailed Implementation

[0055] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification.

[0056] The core sensing circuit of a temperature sensor generally comprises five basic components: a temperature sensing module, a programmable gain amplifier (PGA), an analog-to-digital converter (ADC), an ADC reference generation circuit, and a bandgap reference circuit (BG). The accuracy of a temperature sensor is influenced by these five components. The error sources in the temperature sensing module mainly include the current mirror and the bipolar junction transistor (BJT). The error sources in the PGA mainly include capacitor mismatch, operational amplifier mismatch, and finite gain. The error sources in the ADC, ADC reference generation circuit, and BG are mainly mismatches in their respective components.

[0057] For details, please refer to Figure 1 As shown, a temperature sensing circuit includes a temperature sensing module, a PGA, an ADC, an ADC reference circuit, and a BG. The temperature sensing module includes current mirrors I1 and I2, BJT transistors Q1 and Q2. The emitters of the two BJT transistors in the temperature sensing module can each lead out an output terminal connected to the two input terminals of the PGA. The output terminal of the PGA is connected to the first input terminal of the ADC. The output terminal of the ADC reference generation circuit outputs a reference voltage Vref to the second input terminal of the ADC. The output terminal of the BG is connected to the input terminal of the ADC reference generation circuit. The output of the ADC can be used as the output of the temperature sensing circuit.

[0058] Combination Figure 1In the temperature sensing circuit, the error sources of the temperature sensing module are current mirrors I1 and I2, and BJT transistors Q1 and Q2. The error sources of the PGA are mainly capacitor mismatch, op-amp offset, and finite gain. Taking a CDAC SAR ADC as an example, its error sources are mainly the matching degree of the CDAC (this factor affects the linearity of the ADC) and the comparator offset (this factor will cause the ADC to produce offset error). The error source of the ADC reference generation circuit is mainly its offset, and the error source of the BG is also mainly its offset. Assuming the ADC reference generation circuit is a unity-gain buffer, the offset voltage of the BG is Vos2, and the offset voltage of the ADC reference generation circuit is Vos3, then the reference voltage Vref output by the ADC reference generation circuit is Vbg + Vos2 + Vos3. It can be seen that due to the offsets of the ADC reference generation circuit and the BG, the reference voltage Vref deviates from its ideal value Vbg, which will cause the ADC to produce gain error. Gain error in an ADC is a major problem for temperature sensing circuits, as it means that the slope of the curve relating the output of the temperature sensing circuit to the temperature has changed. Two-point calibration is required to correct the gain error, which increases the overhead and cost of calibration.

[0059] In some embodiments, the error caused by the mismatch of current mirror I1, current mirror I2, BJT Q1 and BJT Q2 can be reduced by performing dynamic element matching (DEM) on the temperature sensing module.

[0060] DEM (Device Modeling) can be used to eliminate or significantly reduce component mismatch errors caused by unavoidable process variations in integrated circuit manufacturing. DEM achieves spatial accuracy through time averaging. Specifically, the temperature sensing module can use a switching network to periodically switch between multiple physically mismatched current mirrors, ensuring that each current mirror is used with equal probability and duration over a sufficiently long period. Consequently, the signal sampled by the PGA (Programmable Gate Array) is actually the average of multiple current mirrors, thus converting the mismatch error into a high-frequency noise that can be easily filtered out.

[0061] While the above methods can reduce the errors caused by the mismatch of the current mirror and BJT in the temperature sensing module to some extent, they do not effectively address the errors caused by other components in the temperature sensing circuit, such as the PGA, ADC, ADC reference generation circuit, and BG, resulting in low accuracy of the temperature sensing circuit.

[0062] To address the aforementioned issues, this specification provides a temperature sensing circuit. Based on a digital image processing (DEM) of the temperature sensing module, the output of the temperature sensing module is integrated and sampled by controlling the PGA. Specifically, during the DEM process, the temperature sensing module is sampled multiple times, and the sampled signals are accumulated. After the DEM is completed, the sampled signal is output to the ADC to eliminate errors caused by PGA operational amplifier mismatch. Furthermore, the ADC can sample the PGA output signal and quantize the sampled signal based on the ADC sampling result and a reference voltage signal, outputting a quantized temperature signal as the output of the temperature sensing circuit. In this specification, by combining DEM of the temperature sensing module with PGA integration sampling, the mismatch errors caused by the internal current mirror and BJT transistor of the temperature sensing module can be eliminated. Furthermore, by storing the offset of the PGA during the integration sampling process, the offset of the PGA operational amplifier can be eliminated, further improving the accuracy of the temperature sensing circuit.

[0063] The temperature sensing circuit in the embodiments of this specification will be described below with reference to the accompanying drawings. It is understood that the temperature sensing circuit in the embodiments of this specification can be a part of the circuit built into a chip, and can be applied to various application scenarios that require the conversion of temperature signals into electrical signals for further data processing. Specifically, this temperature sensing circuit can be applied to sensor chips, including but not limited to biosensor chips based on ultrasonic principles, capacitance principles, and optical principles. For example, it can be an ultrasonic fingerprint chip. The echo time of the ultrasonic fingerprint in the ultrasonic fingerprint chip is related to temperature. Temperature information can be obtained based on the temperature sensing circuit, and then the ultrasonic fingerprint chip can be subjected to more accurate background reduction based on the temperature information. This temperature sensing circuit can also be applied to memory chips (e.g., Flash), control chips (e.g., MCU), etc.

[0064] like Figure 2 As shown in the figure, this specification provides a temperature sensing circuit, including a temperature sensing module 201, a sampling amplification module 202, and an analog-to-digital conversion module 203.

[0065] The control terminal of the temperature sensing module is connected to a first control signal, the output terminal of the temperature sensing module is connected to the input terminal of the sampling amplification module, the output terminal of the sampling amplification module is connected to the first input terminal of the analog-to-digital converter module, the control terminal of the sampling amplification module is connected to a second control signal, the second input terminal of the analog-to-digital converter module is connected to a reference voltage signal, and the control terminal of the analog-to-digital converter module is connected to a third control signal.

[0066] The temperature sensing module is used to perform dynamic component matching based on the first control signal and output a temperature sensing signal. The sampling amplification module is used to perform integral sampling on the output of the temperature sensing module based on the second control signal and output a sampled signal after the dynamic component matching is completed. The analog-to-digital conversion module is used to sample and quantize the sampled signal based on the third control signal and the reference voltage signal and output a quantized temperature signal.

[0067] It is understood that the temperature sensing module may include a temperature-sensing component for sensing temperature. The temperature sensing module can then convert the sensed signal into a temperature signal and output it to the sampling and amplification module. During temperature sensing, the temperature sensing module can perform dynamic element matching (DEM) based on a first control signal. This involves periodically switching between multiple physically mismatched components within the temperature sensing module, ensuring that the probability and time of use for each component are equal over a relatively long period. This transforms the error caused by the mismatch between the components of the temperature sensing module into a high-frequency noise that can be easily filtered out. The DEM operation of the temperature sensing module can be achieved through the first control signal.

[0068] In some embodiments of this specification, the temperature sensing module may include a switch network, and the first control signal may include control signals for turning multiple switches in the switch network on and off, or the first control signal may include control signals for switching different output terminals of the switches in the switch network. For example, the first control signal may include multiple sub-signals, each sub-signal corresponding to the control of turning a switch on / off in the switch network. By controlling multiple switches in the switch network based on multiple sub-signals, a DEM of the temperature sensing module can be generated.

[0069] It can be understood that the sampling amplification module can perform integral sampling of the temperature sensing signal output by the temperature sensing module during DEM (Digital Estimation) based on the second control signal. This integral sampling means the sampling amplification module operates in integral form. That is, each time the temperature sensing module performs a DEM, the sampling amplification module, under the control of the second control signal, can sample and amplify once. The amplified result is not directly output but is accumulated at the output of the sampling amplification module. After the dynamic element matching of the temperature sensing module is completed, the sampling amplification module, under the control of the second control signal, can output the accumulated value of multiple samples as a sample signal. The second control signal can be set correspondingly to the first control signal to achieve sampling amplification after each DEM by the temperature sensing module. The second control signal can include two levels: a first level and a second level. The sampling amplification module can sample and amplify the output of the temperature sensing module at the first level, and can output the sample signal obtained from integral sampling while the sampling amplification remains at the first level for an extended period. For example, the first level can be a high level, which can be represented as the number "1", and the second level can be a low level, which can be represented as the number "0"; or, the first level can be a low level, which can be represented as the number "0", and the second level can be a high level, which can be represented as the number "1".

[0070] In the embodiments of this specification, by means of integral sampling, the operational amplifier offset of the sampling amplification module can be canceled in each sampling process, and by integrating multiple samples, noise interference in the operation of the sampling amplification module can be better suppressed, thereby reducing the output error of the sampling amplification module.

[0071] In some embodiments of this specification, integral sampling can be implemented using a capacitor located in the sampling amplification module. That is, during integration, the capacitor in the sampling amplification module can be reset each time a sample is taken, and the operational amplifier offset of the sampling amplification module is stored on the capacitor. After each sample, integration is performed, and the sampling result from the temperature sensing module is transferred to the capacitor for storage. At this time, the operational amplifier offset can be canceled out. After multiple samplings are completed, the accumulated sampling results stored on the capacitor are output, which can eliminate operational amplifier offset while suppressing noise interference.

[0072] It can be understood that after the sampling amplification module outputs the sampling signal, the analog-to-digital conversion module can sample the sampling signal based on the third control signal, and quantize the sampled signal based on the reference voltage signal, outputting a quantized temperature signal as the output signal of the temperature sensing circuit. For example, the sampling amplification module may include a comparator, with the sampling signal and the reference voltage signal respectively connected to the two output terminals of the comparator. The third control signal can be connected to the control terminal of the comparator. Under the control of the third control signal, the comparator can sample the sampling signal at one input terminal, compare the sampling result with the reference voltage signal, and output the comparison result as the quantized temperature signal. The third control signal may include a first level and a second level, for example, a pulse signal. Therefore, the analog-to-digital conversion module can sample and quantize the sampling signal output by the sampling amplification module when the first level is applied. For example, the first level can be a high level, which can represent the digital "1", and the second level can be a low level, which can represent the digital "0"; or, the first level can be a low level, which can represent the digital "0", and the second level can be a high level, which can represent the digital "1".

[0073] In the embodiments described in this specification, when the temperature sensing circuit is working, it can continuously sense the temperature of the object to be sensed based on the temperature sensing module. During this process, the temperature sensing module can perform a DEM based on the first control signal and output the corresponding temperature sensing signal. Under the control of the second control signal, the sampling amplification module can sample and amplify the temperature sensing signal output by the temperature sensing module after each DEM, and accumulate the sampling amplification result at the output terminal of the sampling amplification module. After one cycle of DEM of the temperature sensing module ends, the sampling amplification module can output the accumulated value of multiple sampling results as a sampling signal under the control of the second control signal. At this time, the analog-to-digital conversion module can sample the sampling signal under the control of the third control signal, and quantize the sampled signal based on the reference voltage signal to output a quantized temperature signal.

[0074] In the embodiments of this specification, the DEM of the temperature sensing module can be realized by controlling the first control signal. The combination of the first control signal and the second control signal can realize the integration sampling of the sampling amplification module at the same time as the DEM. In addition, the mismatch error caused by the mismatch of internal components of the temperature sensing module can be eliminated. Furthermore, the operational amplifier mismatch of the sampling amplification module can be eliminated by storing the mismatch during the integration sampling process, thereby further improving the accuracy of the temperature sensing circuit.

[0075] In some embodiments of this specification, the first control signal, the second control signal, and the third control signal may each include a first level and a second level. The number of level changes of the first control signal within one cycle may correspond to the number of times the temperature sensing module performs a DEM. The distribution and proportion of each level in the first, second, and third control signals may be set accordingly. For example, the sampling amplification module may perform sampling amplification during the time period corresponding to the first level of the second control signal, and the analog-to-digital conversion module may perform sampling quantization during the time period corresponding to the first level of the third control signal. Thus, each segment of the first level of the second control signal may be set to cover every level change moment of the first control signal, and the first level of the third control signal may be set to be within the time period corresponding to the long-term first level of the second control signal.

[0076] refer to Figure 3 As shown, in some embodiments of this specification, the temperature sensing module may include multiple current mirrors (e.g., Figure 3 (current mirrors 11 to 18), switching network, first transistor (e.g.) Figure 3 In the transistor Q1) and the second transistor (e.g. Figure 3 (transistor Q2 in the middle). Figure 3 The example uses eight current mirrors. The switch network can include a first switch (e.g., [missing information]) corresponding to each current mirror. Figure 3 Switches s1a to s8a in the middle) and the second switch (e.g. Figure 3 Switches s1b to s8b in the transistor, and a third switch corresponding to each transistor (e.g., ... Figure 3 The switch s9a) and the fourth switch (e.g. Figure 3 (Switch s9a in the middle).

[0077] Multiple current mirrors have their input terminals connected in parallel to a power supply. The first terminal of each first switch is connected to the output terminal of its corresponding current mirror. The second terminals of the multiple first switches are connected in parallel to the first terminal of the third switch corresponding to the first transistor and the first terminal of the fourth switch corresponding to the second transistor. The first terminal of each second switch is connected to the output terminal of its corresponding current mirror. The second terminals of the multiple second switches are connected in parallel to the first terminals of the third and fourth switches corresponding to the second transistor. The second terminals of the third and fourth switches corresponding to the first transistor are connected to the first electrode of the first transistor. The second terminals of the third and fourth switches corresponding to the second transistor are connected to the first stage of the second transistor. The control electrode and second stage of the first transistor, as well as the control electrode and second electrode of the second transistor, are grounded. The parallel connection of the second terminals of the multiple first switches can be connected to the first input terminal of the sampling amplification module, and the parallel connection of the second terminals of the multiple second switches can be connected to the second input terminal of the sampling amplification module.

[0078] It is understandable that the number of current mirrors in the temperature sensing module is roughly twice the number of times the temperature sensing module performs DEM (Digital Echo Model). For example, Figure 3 The temperature sensing module includes eight current mirrors, which allows for 16 DEMs of the module. The current mirrors can provide bias current to the first and second transistors.

[0079] It is understood that the first control signal may include control signals corresponding to multiple first switches, multiple second switches, two third switches, and two fourth switches. The control signal corresponding to each switch may include a first level and a second level, and each switch may be closed when the control signal is at the first level and open when the control signal is at the second level. For example, the first level may be a high level and the second level may be a low level; or the first level may be a low level and the second level may be a high level.

[0080] It is understandable that during the DEM (Digital Estimation Model) of the temperature sensing module, the control signals of the first and second switches corresponding to each current mirror can be opposite signals. For example, for Figure 3 In the temperature sensing module, the current mirror I1 has a control signal of switch s1b at a second level when the control signal of its corresponding switch s1a is at the first level, and vice versa. Correspondingly, the control signal of the third switch corresponding to the transistor can also be the opposite of the control signal of the third switch. For example, for... Figure 3 In the temperature sensing module, when the control signal of the transistor Q1 corresponding to switch s9a is at the first level, the control signal of switch s9b is at the second level; when the control signal of switch s9a is at the second level, the control signal of switch s9b is at the first level.

[0081] It can be understood that the first transistor and the second transistor can be temperature-sensing elements in a temperature-sensing module, used to sense temperature. The first transistor and the second transistor can be temperature-sensitive transistors, whose internal PN junctions have temperature characteristics. Therefore, based on different temperatures of the object to be sensed, the voltage between the first electrode and the control electrode of the transistor will change accordingly. The temperature of the object to be sensed can be calculated by detecting the voltage difference between the first electrode and the control electrode. For example, the first transistor and the second transistor can be BJT transistors, MOSFET transistors, diodes, etc.

[0082] In some embodiments of this specification, the temperature sensing module may include more transistors than in the embodiments described above, with each transistor corresponding to two switches. For example, the temperature sensing module may also include a third transistor and a fourth transistor, each corresponding to a third switch and a fourth switch. In other embodiments, each transistor may correspond to more switches, such as four transistors, each corresponding to four switches. Correspondingly, each current mirror may also correspond to four switches, and the temperature sensing module may include four outputs, etc. This specification does not impose any limitations on these aspects.

[0083] In some embodiments of this specification, the sampling amplification module may include an operational amplifier, two sampling capacitors, and two feedback capacitors. The first terminal of each sampling capacitor is connected to an input terminal of the operational amplifier, and the second terminal of each sampling capacitor is connected to an output terminal of the temperature sensing module via a fifth switch. A first node is provided between the second terminal of each sampling capacitor and the fifth switch, and the two first nodes are respectively connected to one end of a sixth switch. A second node is provided between each sampling capacitor and the input terminal of the operational amplifier, and each second node is connected to an output terminal of the operational amplifier via a fifth switch. The second node may also be connected to a reset signal via a feedback capacitor and a seventh switch. A third node is provided between each feedback capacitor and the seventh switch, and each third node is connected to an output terminal of the operational amplifier via a sixth switch.

[0084] Accordingly, the second control signal may include a first sub-signal, a second sub-signal, and a third sub-signal. Each sub-signal controls the on / off state of the fifth, sixth, and seventh switches, respectively. Each sub-signal may include a first level and a second level, controlling the corresponding switch to close when the sub-signal is at the first level and controlling the corresponding switch to open when the sub-signal is at the second level. For example, the first level may be high and the second level may be low; or the first level may be low and the second level may be high.

[0085] In some embodiments of this specification, the structure of the sampling amplification module can be as follows: Figure 4 As shown, the operational amplifier can be pga_op, the sampling capacitor can be Cs, the feedback capacitor can be Cf, the first sub-signal corresponding to the fifth switch can be clks, the second sub-signal corresponding to the sixth switch can be clka, and the third sub-signal corresponding to the seventh switch can be cap_rst. The timing diagram of each sub-signal can be shown below. Figure 5 As shown.

[0086] refer to Figure 5As shown, taking a high level for the first level and a low level for the second level as an example, during the specific operation of the sampling amplification module, the output of the temperature sensing module can be sampled once when the first sub-signal clks corresponding to the fifth switch is high. During the first sampling, the feedback capacitor Cf can be reset based on the reset signal when the third sub-signal cap_rst corresponding to the seventh switch is high. Subsequently, the offset of the operational amplifier pga_op can be stored on the feedback capacitor Cf during subsequent sampling. After each sampling of the temperature sensing module's output, the output of the operational amplifier pga_op can be integrated once when the second sub-signal clka corresponding to the sixth switch is high, and the currently sampled output of the temperature sensing module is transferred to the feedback capacitor Cf for storage. After the DEM of the temperature sensing module is completed, taking 16 DEMs as an example, the operational amplifier samples the output of the temperature sensing module 16 times. The second sub-signal clka remains high for a long time, and the operational amplifier can output the sum of the 16 samples. Subsequently, the analog-to-digital converter module can sample and quantize this sum of voltages and output it.

[0087] In some embodiments of this specification, when the sampling amplification module outputs the integrated sampled voltage signal, it may output a weighted sum of multiple sampled signals, where the weighting coefficient of each signal can be the ratio of the sampling capacitor to the feedback capacitor. For example, when the ratio of the sampling capacitor to the feedback capacitor is 1, the sampling signal output by the operational amplifier can be the sum of multiple samples.

[0088] In some embodiments of this specification, the output of the temperature sensing module may include a first temperature sensing sub-signal and a second temperature sensing sub-signal. The sampling amplification module integrates and samples the two temperature sensing sub-signals to obtain two sampled sub-signals, including the first sampled sub-signal and the second sampled sub-signal. Correspondingly, the third control signal may include a sampling control sub-signal for sampling the output of the sampling amplification module, and a switching control sub-signal for exchanging the two sampled sub-signals output by the sampling amplification module.

[0089] For example, the first input terminal of the analog-to-digital converter (ADC) module may include a first sub-input terminal and a second sub-input terminal. These two sub-input terminals are respectively connected to the first and second output terminals of the sampling amplification module, or they are respectively connected to the second and first output terminals of the sampling amplification module. Both the sampling control sub-signal and the switching control sub-signal may include a first level and a second level. When the sampling control sub-signal is at the first level, the two sampling sub-signals output by the sampling amplification module can be sampled. When the switching control sub-signal is at the second level, the first sub-input terminal of the ADC module can be connected to the first output terminal of the sampling amplification module pair, and the second sub-input terminal of the ADC module can be connected to the second output terminal of the sampling amplification module pair. Similarly, when the switching control sub-signal is at the first level, the first sub-input terminal of the ADC module can be connected to the second output terminal of the sampling amplification module pair, and the second sub-input terminal of the ADC module can be connected to the first output terminal of the sampling amplification module pair. Different levels of the third control signal can correspond to different sampling periods of different ADC modules.

[0090] In some embodiments of this specification, the analog-to-digital conversion module may include a switch submodule consisting of multiple switches and an analog-to-digital converter. The switch submodule is connected to the output terminal of the sampling amplification module and the input terminal of the analog-to-digital converter. The control terminal of the switch submodule is connected to the switching control sub-signal, and the control terminal of the analog-to-digital converter is connected to the sampling control sub-signal. Furthermore, under the control of the switching control sub-signal, the switch submodule can cause the first and second output terminals of the sampling amplification module to be connected to the first and second sub-input terminals of the analog-to-digital converter, respectively, or the first and second output terminals of the sampling amplification module to be connected to the second and first sub-input terminals of the analog-to-digital converter, respectively. Under the control of the sampling control sub-signal, the analog-to-digital converter can sample the sampling sub-signals connected to the two sub-input terminals of the analog-to-digital converter.

[0091] For example, the switching submodule may include two first switching switches and two second switching switches. The first sub-input terminal of the analog-to-digital converter can be connected to the first output terminal and the second output terminal of the sampling amplification module through the first switching switches and the second switching switches, respectively. The second sub-input terminal of the analog-to-digital converter can be connected to the second output terminal and the first output terminal of the sampling amplification module through the first switching switches and the second switching switches, respectively. The control terminals of each first switching switch can be connected to exchange control sub-signals through NOT gates, and the control terminals of each second switching switch can be connected to exchange control sub-signals through two series NOT gates.

[0092] Furthermore, taking the switching control signal, which includes both low and high levels, as an example: When the switching control sub-signal is low, the control signal connected to the two first switching switches is high. This connects the first sub-input terminal of the analog-to-digital converter (ADC) to the first output terminal of the sampling amplification module, and the second sub-input terminal of the ADC to the second output terminal of the sampling amplification module. At this time, under the control of the sampling control sub-signal, the ADC can control its first sub-input terminal to sample the first sampling sub-signal output from the first output terminal of the sampling amplification module, and its second sub-input terminal to sample the second sampling sub-signal output from the second output terminal of the sampling amplification module. When the switching control sub-signal is high, the control signal connected to the two second switching switches is high. This connects the first sub-input terminal of the ADC to the second output terminal of the sampling amplification module, and the second sub-input terminal of the ADC to the first output terminal of the sampling amplification module. At this time, under the control of the sampling control sub-signal, the ADC can control its first sub-input terminal to sample the second sampling sub-signal output from the second output terminal of the sampling amplification module, and its second sub-input terminal to sample the first sampling sub-signal output from the first output terminal of the sampling amplification module.

[0093] It is understood that in other embodiments, the switching submodule may include more or fewer other devices; the switching control subsignal may also include more other levels; or the first and second sub-input terminals of the analog-to-digital converter may be connected to the first and second output terminals of the sampling amplification module, respectively, when the switching control subsignal is high, and connected to the second and first output terminals of the sampling amplification module, respectively, when the switching control subsignal is low. This specification does not limit this.

[0094] In the embodiments of this specification, based on the third control signal, the input voltage of the analog-to-digital converter (ADC) can be converted from positive to negative by sampling and exchanging the input terminal of the ADC. Then, the difference between the two outputs of the temperature sensing circuit at the digital terminal can be obtained as the sum of the two outputs that eliminate the misalignment of the ADC. Finally, averaging the difference can obtain the final output of the temperature sensing circuit that eliminates the misalignment of the ADC, thereby improving the accuracy of the temperature sensing circuit.

[0095] For example, with Figure 3Taking the ADC (Analog-to-Digital Converter) as an example, swap2 is the exchange control sub-signal in the third control signal, with the first level being high and the second level being low. Vop and Von are two sampling signals output by the sampling amplification module. Assuming Vos1 is the offset voltage of the comparator within the ADC, when swap2=0, the input signal sampled by the ADC is Vin=Vop-Von, and its actual quantized signal is Vin+Vos1. Let's assume the ADC output is D1. When swap2=1, the input signal sampled by the ADC is -Vin=Von-Vop, and its actual quantized signal is -Vin+Vos1. Let's assume the ADC output is D2. Therefore, subtracting the two ADC outputs D1 and D2 and dividing by 2, the result D=(D1-D2) / 2 is the correct quantization result of Vin. This eliminates the influence of the comparator offset within the ADC and improves the accuracy of the temperature sensing circuit. The two values ​​of swap2 correspond to the two samplings of the ADC.

[0096] In some embodiments of this specification, the temperature sensing circuit may further include a reference generation circuit (e.g., an ADC reference generation circuit) and a bandgap reference circuit (e.g., a BG circuit). The output of the bandgap reference circuit is connected to the input of the reference generation circuit, and the output of the reference generation circuit is connected to the second input of the analog-to-digital converter module. The combination of the bandgap reference circuit and the reference generation circuit can output a reference voltage signal to the analog-to-digital converter module, enabling the analog-to-digital converter module to quantize the sampled signal output by the sampling amplification module based on the reference voltage signal.

[0097] It is understandable that a bandgap reference circuit can be used to generate a highly stable initial voltage that is independent of supply voltage and temperature. The reference generation circuit can then use this initial voltage generated by the bandgap reference circuit to generate a suitable reference voltage signal for the analog-to-digital converter module.

[0098] Since the quantization accuracy of the analog-to-digital converter (ADC) module is related not only to the sampled signal output by the sampling amplification module but also to the reference voltage signal, the accuracy of the output signal of the bandgap reference circuit and / or reference generation circuit can affect the accuracy of the ADC module. The accuracy of the output signal of the bandgap reference circuit and / or reference generation circuit is affected by its offset voltage. Therefore, to further improve the accuracy of the temperature sensing circuit, this can be achieved by eliminating the offset voltage of the bandgap reference circuit and / or reference generation circuit.

[0099] In some embodiments of this specification, a fourth control signal can be used to exchange two input signals at the input terminals of the bandgap reference circuit and / or reference generation circuit. The fourth control signal may include a first level and a second level. When the fourth control signal is at the first level, the input signals at the corresponding circuit's input terminals are exchanged; when the fourth control signal is at the second level, the input signals at the corresponding circuit's input terminals are not exchanged. For example, the first level can be high and the second level can be low; or the first level can be low and the second level can be high.

[0100] Furthermore, the switching operation at the input of the bandgap reference circuit and / or reference generation circuit can be achieved through low-frequency chopping. For example, the low-frequency chopping process for the bandgap reference circuit can include modulation and demodulation. For modulation of the bandgap reference circuit: a chopper switch is added to the input of the core circuit (e.g., an operational amplifier) ​​of the bandgap reference circuit. This switch can be controlled by a fourth control signal, which can, for example, alternately switch the polarity of the input signal at a low-frequency clock frequency (e.g., a few kHz to several hundred Hz). Thus, the DC reference signal of the bandgap reference circuit is modulated into an AC square wave signal. Simultaneously, offset and low-frequency noise are also modulated to the vicinity of the corresponding frequency and its odd harmonics. For demodulation of the bandgap reference circuit: after amplification by the core circuit of the bandgap reference circuit, the signal (containing the useful AC square wave and noise) reaches the output. At the output, a synchronous, fully in-phase chopper switch is used to switch the signal again (demodulate). The demodulation process can restore the useful reference signal (which was originally a square wave modulated by the input switch) back to a DC voltage. During demodulation, the offset and noise are modulated a second time, shifting their energy to near a higher frequency. Therefore, the offset voltage can be eliminated by low-pass filtering the demodulated signal. Similarly, the reference generation circuit can employ a similar low-frequency chopping method to achieve input switching.

[0101] In the embodiments described in this specification, the input terminals of the bandgap reference circuit and / or reference generation circuit are swapped through the fourth control signal, and the outputs of the corresponding circuits are also swapped at the same time. Then, by averaging the two quantization outputs of the analog-to-digital conversion module, the error caused by the misalignment of the bandgap reference circuit and / or reference generation circuit can be eliminated, thereby improving the accuracy of the temperature sensing circuit.

[0102] For example, with Figure 3 The diagram illustrates a method for controlling a bandgap reference circuit (i.e., by exchanging control signals) Figure 3 (BG in the middle) and / or reference generation circuit (i.e. Figure 3The input terminals of the ADC reference generation circuit (in the circuit) are swapped. `swap1` is the fourth control signal, which can swap the input terminals of BG and the ADC reference generation circuit. It is understood that in other embodiments, `swap1` can swap only the input terminals of one of the BG and ADC reference generation circuits.

[0103] For example, with Figure 3 Taking the swap operation on the input of BG as an example, assume Vos2 is the offset voltage of BG. When swap1=0, the output voltage of BG is Vbg+Vos2, and the output voltage of the ADC reference generation circuit is also Vbg+Vos2; when swap1=1, the output voltage of BG is Vbg-Vos2, and the output voltage of the ADC reference generation circuit is also Vbg-Vos2. If the ADC quantizes the same input signal twice, the reference voltage signal for the first quantization is Vbg+Vos2, and the reference voltage signal for the second quantization is Vbg-Vos2. Since Vos2 is guaranteed to be much smaller than Vbg (approximately 1.2V), adding the two quantization results and dividing by 2 will give an approximation to quantization with Vbg as the reference voltage. This is illustrated by the swap operation on the input of the ADC reference generation circuit using swap1.

[0104] For example, with Figure 3 Taking the swap1 operation on the input of the ADC reference generation circuit as an example, Vos3 is the offset voltage of the ADC reference generation circuit. When swap1=0, the output voltage of BG is Vbg, and the output voltage of the ADC reference generation circuit is Vbg + Vos3; when swap1=1, the output voltage of BG is Vbg, and the output voltage of the ADC reference generation circuit is Vbg - Vos3. If the ADC quantizes the same input signal twice, the reference voltage signal for the first quantization is Vbg + Vos3, and the reference voltage signal for the second quantization is Vbg - Vos3. Since Vos3 is guaranteed to be much smaller than Vbg (approximately 1.2V), adding the two quantization results and dividing by 2 can approximate the quantization performed with Vbg as the reference voltage.

[0105] For example, with Figure 3Taking the swap1 operation on the input terminals of the BG and ADC reference generation circuit as an example, swap1 is the fourth control signal, which can perform swap operations on the input terminals of both the BG and the ADC reference generation circuit. Assume Vos2 is the offset voltage of the BG and Vos3 is the offset voltage of the ADC reference generation circuit. When swap1=0, the output voltage of the BG is Vbg+Vos2, and the output voltage of the ADC reference generation circuit is Vbg+Vos2+Vos3; when swap1=1, the output voltage of the BG is Vbg-Vos2, and the output voltage of the ADC reference generation circuit is Vbg-Vos2-Vos3. If the ADC quantizes the same input signal twice, the reference voltage signal after the first quantization is Vbg+Vos2+Vos3, and the reference voltage signal after the second quantization is Vbg-Vos2-Vos3. Since Vos2 and Vos3 are guaranteed to be much smaller than Vbg (approximately 1.2V), the sum of the two quantization results divided by 2 can be infinitely close to the quantization performed with Vbg as the reference voltage.

[0106] In some embodiments of this specification, by setting the first control signal, the second control signal, the third control signal, and the fourth control signal, and then by calculating the output of the temperature sensing circuit multiple times, the operational amplifier offset of the sampling amplification module, the offset of the bandgap reference circuit, the reference generation circuit, and the analog-to-digital conversion module can be eliminated simultaneously, thereby improving the accuracy of the temperature sensing circuit.

[0107] Specifically, during the period when the temperature sensing module finishes performing DEM (Digital Estimation) controlled by the first control signal, the sampling amplification module can be continuously outputting the integrated sampling results for a certain period through the second control signal. Then, during this period, the analog-to-digital converter (ADC) module can be controlled by the third control signal to sample the sampling signal output by the sampling amplification module, and the input terminals of the ADC module can be switched at different sampling periods. Simultaneously, the input terminals of the bandgap reference circuit and the reference generation circuit can be switched at different sampling periods through the fourth control signal. To eliminate the misalignment of each module, the ADC module needs to sample a multiple of 4 times during this period. Every four samples, the fourth control signal controls the input terminals of the bandgap reference circuit and the reference generation circuit to switch twice, and the third control signal controls the input terminals of the ADC module to switch once.

[0108] In some embodiments of this specification, the structure of the temperature sensing circuit can be as follows: Figure 3As shown, the temperature sensing module can include 8 current mirrors, enabling 16 DEMs of the module. The timing sequence of switches s1a to s9a is the reverse of that of switches s1b to s9b; that is, when switches s1a to s9a are high, switches s1b to s9b are low, and vice versa. The temperature sensing module can include two outputs: Vip and Vin. The analog-to-digital converter (ADC) module (the one shown in the diagram) has the following control sub-signals: swap2, adc_clks, and swap1 for the control signals of BG and the ADC reference generation circuit. The BG output signal is Vbg, and the reference voltage signal output by the ADC reference generation circuit is Vref. The control signals for the sampling amplification module include pga_clka, pga_clks, and cap_rst. The timing diagrams for each control signal are shown below. Figure 6 As shown. The operating timing sequence of switches s1a to s9a is the opposite of that of switches s1b to s9b. That is, when switches s1a to s9a are at a high level, switches s1b to s9b are at a low level, and when switches s1a to s9a are at a low level, switches s1b to s9b are at a high level.

[0109] The working principle of the temperature sensing circuit is as follows: A dynamic element matching (DEM) is performed on the temperature sensing module. Each time the dynamic element matching (PGA) is performed, the output of the temperature sensing module is sampled. A total of 16 DEMs are performed on the temperature sensing module, and the PGA samples 16 values. After all 16 values ​​are sampled, pga_clka is pulled high, the PGA enters amplification mode, and stably outputs the sum of the 16 sampled voltages. Then, the ADC samples and quantizes the output voltage of the PGA. During the ADC sampling and quantization process, four samples are performed. The input terminals are not swapped in the first two samples, and swapped in the last two samples. For odd-numbered samples, the input terminals of BG and the ADC reference generation circuit are not swapped, while for even-numbered samples, they are swapped. The results of the four consecutive ADC sampling and quantization are recorded as D1, D2, D3, and D4, respectively. Then, the output value D of the temperature sensing circuit after eliminating various irrational factors can be obtained at the digital end through the following processing:

[0110] Formula (1)

[0111] The specific proof process can be as follows:

[0112] Formula (2)

[0113] Formula (3)

[0114] Formula (4)

[0115] Formula (5)

[0116] Then we have:

[0117] Formula (6)

[0118] When Vos2 and Vos3 are much smaller than Vbg, utilize (when If it is true at that time, then we can get:

[0119] Formula (7)

[0120] In the embodiments of this specification, the error caused by the PGA operational amplifier offset can be offset by the integral offset storage structure of the PGA. By swapping the input terminals of the ADC, the ADC reference generation circuit and the BG, the error caused by the offset of the corresponding circuit module can be eliminated by calculation at the digital end. By performing DEM operation on the temperature sensing module, the error caused by the mismatch of internal components of the temperature sensing module can be eliminated, thereby improving the accuracy of the temperature sensing circuit. Moreover, it does not require complex calibration processing, which can reduce the calibration overhead and cost.

[0121] Based on the aforementioned temperature sensing circuit, this specification also provides a chip, including the temperature sensing circuit and processing unit described in the foregoing embodiments.

[0122] The output terminal of the temperature sensing circuit is connected to the processing unit. The processing unit is used to receive the temperature quantization signal output by the analog-to-digital conversion module of the temperature sensing circuit, and to determine the temperature output result based on at least two consecutive temperature quantization signals. The temperature output result is used to characterize the temperature signal sensed by the temperature sensing circuit.

[0123] For example, with Figure 2Taking the temperature sensing circuit shown as an example, during operation, the temperature sensing module continuously senses the temperature of the object to be sensed. During the sensing process, the temperature sensing module performs a digital image (DEM) based on a first control signal and outputs the corresponding temperature signal. Under the control of a second control signal, the sampling amplification module samples and amplifies the temperature signal output by the temperature sensing module after each DEM, accumulating the amplification result at its output. After one DEM cycle of the temperature sensing module ends, the sampling amplification module, under the control of the second control signal, outputs the accumulated value of multiple sampling results as a sample signal. Furthermore, the analog-to-digital conversion module samples the sample signal under the control of a third control signal and quantizes the sampled signal based on a reference voltage signal, outputting a quantized temperature signal. This quantized temperature signal can be sent to the processing unit as a primary output of the temperature sensing circuit. When the processing unit receives two consecutive quantized temperature signals, it averages the two signals to obtain the temperature output value.

[0124] In other embodiments, with Figure 3 The temperature sensing circuit shown and Figure 6 Taking the working timing shown as an example, after receiving four consecutive temperature quantization signals D1, D2, D3, and D4, the processing unit can calculate the temperature output result using the aforementioned formula (1).

[0125] In some embodiments of this specification, the processing unit can communicatively connect to the control terminals of each circuit / module of the temperature sensing circuit to output control signals to each circuit / module to control error elimination. For example, the processing unit can communicatively connect to the control terminals of the temperature sensing module, the sampling amplification module, the analog-to-digital conversion module, and the input terminals of the bandgap reference circuit and / or the reference generation circuit, and output corresponding first control signals, second control signals, third control signals, and fourth control signals to the corresponding modules to control the error elimination of each module.

[0126] Furthermore, error elimination trigger events or error elimination stop events can be set in the processing unit. When the processing unit detects the corresponding event, it can output a control signal to the temperature sensing circuit or stop outputting control signals to the temperature sensing circuit. For example, the error elimination trigger event can be an event that requires higher temperature measurement accuracy and where the temperature sensor is not calibrated, while the error elimination stop event can be an event where the processing unit or other software performs test calibration and is a multi-point calibration.

[0127] Furthermore, the processing unit can be configured with multiple registers. The processing unit can control whether to output control signals to the corresponding modules of the temperature sensing circuit by setting the values ​​of each register. For example, two registers can be configured, each corresponding to the analog-to-digital conversion module and the reference generation circuit, respectively. These registers are used to control whether to output a third control signal and a fourth control signal to the analog-to-digital conversion module and the reference generation circuit, thereby controlling the connection or disconnection of the control signals of the corresponding modules. Of course, in other embodiments, corresponding registers can also be configured for the temperature sensing module and the sampling amplification module, and the connection or disconnection of the control signals of each circuit / module can be controlled through these registers.

[0128] For example, with Figure 3 Taking the temperature sensing circuit as an example, registers rg_adc_vref_swap_en and rg_adc_vin_swap_en can be set in the processing unit. Register rg_adc_vref_swap_en controls the enabling or disabling of the swap1 function corresponding to the ADC reference generation circuit, and register rg_adc_vin_swap_en controls the enabling or disabling of the swap2 function corresponding to the ADC. Furthermore, the processing unit can process the temperature quantization signal output by the temperature sensing circuit based on the values ​​of each register. Specifically, when the value of register rg_adc_vref_swap_en is determined to be 1, the processing unit can calculate the temperature output result based on four consecutive temperature quantization signals D1, D2, D3, and D4 using the formula: D=(D1+D3-D2-D4) / 4. When the value of register rg_adc_vref_swap_en is determined to be 0, the processing unit can calculate the temperature output result based on four consecutive temperature quantization signals D1, D2, D3, and D4 using the formula: D=(D1+D2+D3+D4) / 4.

[0129] Although the process described above includes multiple operations that occur in a specific order, it should be clearly understood that these processes may include more or fewer operations, which may be executed sequentially or in parallel (e.g., using parallel processors or a multithreaded environment).

[0130] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this specification. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0131] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0132] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0133] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0134] Those skilled in the art will understand that the embodiments of this specification can be provided as methods, systems, or computer program products. Therefore, the embodiments of this specification can take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware aspects. Furthermore, the embodiments of this specification can take the form of computer program products implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0135] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, system embodiments are basically similar to method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. In the description of this specification, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments in this specification. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0136] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A temperature sensing circuit, characterized in that, include: The system comprises a temperature sensing module, a sampling amplification module, an analog-to-digital converter (ADC), a reference generation circuit, and a bandgap reference circuit. The control terminal of the temperature sensing module is connected to a first control signal, the output terminal of the temperature sensing module is connected to the input terminal of the sampling amplification module, the output terminal of the sampling amplification module is connected to the first input terminal of the ADC, the control terminal of the sampling amplification module is connected to a second control signal, the second input terminal of the ADC is connected to a reference voltage signal, and the control terminal of the ADC is connected to a third control signal. The temperature sensing module is used to perform dynamic component matching based on the first control signal and output a temperature sensing signal; The sampling amplification module is used to perform integral sampling on the output of the temperature sensing module based on the second control signal, and output the sampling signal after the dynamic element matching is completed; The analog-to-digital conversion module is used to sample and quantize the sampled signal based on the third control signal and the reference voltage signal, and output a temperature quantization signal. The sampling amplification module includes an operational amplifier, two sampling capacitors, and two feedback capacitors; The first end of each sampling capacitor is connected to an input terminal of an operational amplifier, and the second end of each sampling capacitor is connected to an output terminal of a temperature sensing module through a fifth switch. A first node is provided between the second end of each sampling capacitor and the fifth switch, and each first node is connected to one end of a sixth switch. Each sampling capacitor is connected to a second node between itself and the input terminal of the operational amplifier. Each second node is connected to an output terminal of the operational amplifier through a fifth switch. Each second node is connected to a reset signal through a feedback capacitor and a seventh switch. Each feedback capacitor is connected to a third node between itself and the seventh switch, and each third node is connected to an output terminal of the operational amplifier through a sixth switch. The fifth switch, the sixth switch, and the seventh switch are connected to the second control signal; The output of the bandgap reference circuit is connected to the input of the reference generation circuit, and the output of the reference generation circuit is connected to the second input of the analog-to-digital converter module; the fourth control signal is connected to the two inputs of the reference generation circuit, and the fourth control signal is used to exchange the two input signals of the reference generation circuit.

2. The temperature sensing circuit according to claim 1, characterized in that, The first control signal, the second control signal, and the third control signal all include a first level and a second level; The temperature sensing module is used to perform dynamic component matching when the level of the first control signal changes; The sampling amplification module performs integral sampling on the output of the temperature sensing module when the second control signal is at the first level; The analog-to-digital conversion module performs sampling and quantization on the sampled signal when the third control signal is at the first level.

3. The temperature sensing circuit according to claim 2, characterized in that, The first time period corresponding to each segment of the first level of the second control signal can cover the time of each level change of the first control signal, and the second time period corresponding to the first level of the third control signal matches the third time period corresponding to the first control signal being at the second level and the second control signal being at the first level.

4. The temperature sensing circuit according to claim 1, characterized in that, The temperature sensing module includes multiple current mirrors, a switching network, a first transistor, and a second transistor. The switching network includes a first switch and a second switch corresponding to each current mirror, and a third switch and a fourth switch corresponding to each transistor. The input terminals of the plurality of current mirrors are connected in parallel to the power supply, the first terminal of each first switch is connected to the output terminal of the corresponding current mirror, and the second terminals of the plurality of first switches are connected in parallel to the first terminal of the third switch corresponding to the first transistor and the first terminal of the fourth switch corresponding to the second transistor. The first terminal of each second switch is connected to the output terminal of the corresponding current mirror. The second terminals of multiple second switches are connected in parallel and connected to the first terminal of the third switch corresponding to the second transistor and the first terminal of the fourth switch corresponding to the first transistor. The second terminals of the third and fourth switches corresponding to the first transistor are connected to the first electrode of the first transistor, and the second terminals of the third and fourth switches corresponding to the second transistor are connected to the first stage of the second transistor. The control electrode and the second electrode of the first transistor, as well as the control electrode and the second electrode of the second transistor, are grounded; The second terminals of the plurality of first switches are connected in parallel and then connected to the first input terminal of the sampling amplification module. The second terminals of the plurality of second switches are connected in parallel and then connected to the second input terminal of the sampling amplification module.

5. The temperature sensing circuit according to claim 1, characterized in that, The second control signal includes a first sub-signal, a second sub-signal, and a third sub-signal, each sub-signal corresponding to controlling the on / off state of the fifth switch, the sixth switch, and the seventh switch, respectively.

6. The temperature sensing circuit according to claim 1 or 5, characterized in that, When the sampling amplification module is working: Before the operational amplifier performs its first sampling, the seventh switch controls the feedback capacitor to reset according to the reset signal based on the second control signal. The fifth switch, based on the second control signal, controls the operational amplifier to sample the output of the temperature sensing module once, and stores the offset of the operational amplifier in the feedback capacitor; The sixth switch, based on the second control signal, controls the output of the operational amplifier to perform an integral sampling once, and transmits the corresponding output to the feedback capacitor for storage. After the dynamic element matching is completed, the sixth switch controls the operational amplifier to output a sampling signal based on the second control signal.

7. The temperature sensing circuit according to claim 1, characterized in that, The sampling signal includes a first sampling sub-signal and a second sampling sub-signal; The third control signal includes a sampling control sub-signal and a switching control sub-signal. The sampling control sub-signal is used to sample the output of the sampling amplification module, and the switching control sub-signal is used to switch the first sampling sub-signal and the second sampling sub-signal output by the sampling amplification module.

8. The temperature sensing circuit according to claim 7, characterized in that, The sampling amplification module includes a first output terminal and a second output terminal; the first input terminal of the analog-to-digital conversion module includes a first sub-input terminal and a second sub-input terminal. The first control terminal of the sampling amplification module is connected to the sampling control sub-signal, and the second control terminal of the sampling amplification module is connected to the switching control sub-signal; The first and second sub-input terminals of the analog-to-digital converter module can be connected to the first and second output terminals of the sampling amplification module, respectively, under the control of the switching control sub-signal accessed by the second control terminal, or to the second and first output terminals of the sampling amplification module, respectively; and the analog-to-digital converter module can sample the sampling sub-signals accessed by the two sub-input terminals under the control of the sampling control sub-signal accessed by the first control terminal.

9. The temperature sensing circuit according to claim 8, characterized in that, The analog-to-digital conversion module includes a switch submodule consisting of multiple switches and an analog-to-digital converter. The switch submodule is connected to the output terminal of the sampling amplification module and the input terminal of the analog-to-digital converter. The control terminal of the switch submodule is connected to the switching control sub-signal, and the control terminal of the analog-to-digital converter is connected to the sampling control sub-signal. Under the control of the switching control sub-signal, the switching sub-module can make the following: the first output terminal and the second output terminal of the sampling amplification module are respectively connected to the first sub-input terminal and the second sub-input terminal of the analog-to-digital converter, or the first output terminal and the second output terminal of the sampling amplification module are respectively connected to the second sub-input terminal and the first sub-input terminal of the analog-to-digital converter. The analog-to-digital converter (ADC) is capable of sampling the sampling sub-signals of the two sub-input terminals connected to the ADC under the control of the sampling control sub-signal.

10. The temperature sensing circuit according to claim 1, characterized in that, The fourth control signal is also connected to the two input terminals of the bandgap reference circuit, and the fourth control signal is used to exchange the two input signals of the input terminals of the bandgap reference circuit.

11. A chip, characterized in that, include: The temperature sensing circuit and processing unit according to any one of claims 1 to 10, wherein the processing unit is connected to the output terminal of the analog-to-digital conversion module of the temperature sensing circuit, the processing unit is used to receive the temperature quantization signal output by the analog-to-digital conversion module, and determine the temperature output result based on at least two consecutive temperature quantization signals received, the temperature output result being used to characterize the temperature signal sensed by the temperature sensing circuit.

12. The chip according to claim 11, characterized in that, The processing unit is communicatively connected to the control terminal of at least one of the temperature sensing module, sampling amplification module, or analog-to-digital conversion module of the temperature sensing circuit, and the processing unit is used to output corresponding control signals to the control terminals of each module.

13. The chip according to claim 12, characterized in that, When the processing unit detects a preset error elimination trigger event, it outputs a corresponding control signal to the control terminals of each module of the temperature sensing circuit; or, When the processing unit detects a preset error elimination stop event, it stops outputting corresponding control signals to the control terminals of each module of the temperature sensing circuit.

14. The chip according to claim 12, characterized in that, The processing unit is provided with at least one register, which corresponds to at least one of the temperature sensing module, sampling amplification module or analog-to-digital conversion module of the temperature sensing circuit. The value of the register is used to control the on / off state of the control signal output by the processing unit to the corresponding module of the temperature sensing circuit.

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