阅读说明：本技术 一种可变量程温度传感器 (Variable range temperature sensor ) 是由 毕见鹏 于 2021-01-12 设计创作，主要内容包括：本发明提供一种可变量程温度传感器,包括：电流产生电路、量程切换电路、调制器电路和计数器电路；电流产生电路用于根据待测温度生成测量电流；量程切换电路用于根据比特流控制信号和量程控制向量信号生成转换电流；调制器电路用于对转换电流进行模数调制,生成比特流信号；计数器电路用于接收比特流信号,并根据比特流信号的占空比信息,输出待测温度的测量结果。本发明能够在传统温度传感器的基础上,通过片上改变电流组合运算,实现不同量程切换,大量程测量范围大,小量程测量精度高,付出极小的成本扩展了温度传感器的应用场景,可以在常规测温基础上,满足体温等小量程高精度温度测量需求,提高芯片的集成度,减小芯片的面积。(The invention provides a variable range temperature sensor, comprising: the device comprises a current generating circuit, a range switching circuit, a modulator circuit and a counter circuit; the current generating circuit is used for generating measuring current according to the temperature to be measured; the range switching circuit is used for generating conversion current according to the bit flow control signal and the range control vector signal; the modulator circuit is used for carrying out analog-to-digital modulation on the conversion current to generate a bit stream signal; the counter circuit is used for receiving the bit stream signal and outputting the measurement result of the temperature to be measured according to the duty ratio information of the bit stream signal. The invention can realize the switching of different measuring ranges by changing the current combination operation on the chip on the basis of the traditional temperature sensor, has large measuring range of a large measuring range and high measuring precision of a small measuring range, expands the application scene of the temperature sensor with extremely low cost, can meet the requirements of the temperature measurement of the small measuring range, high precision, such as body temperature and the like on the basis of the conventional temperature measurement, improves the integration level of the chip and reduces the area of the chip.)

1. A variable range temperature sensor, comprising at least:

the device comprises a current generating circuit, a range switching circuit, a modulator circuit and a counter circuit;

the current generating circuit is used for generating a measuring current according to the temperature to be measured;

the range switching circuit is used for converting the measuring current according to a bit stream control signal and a range control vector signal to generate a conversion current;

the modulator circuit is used for carrying out analog-to-digital modulation on the conversion current to generate a bit stream signal;

and the counter circuit is used for receiving the bit stream signal and outputting the measurement result of the temperature to be measured according to the duty ratio information of the bit stream signal.

2. The variable range temperature sensor of claim 1, wherein, where the measurement current comprises a first current and a second current different from the first current, the range switching circuit comprises:

the current mirror circuit comprises a first current mirror group consisting of m parallel current mirrors and a second current mirror group consisting of n parallel current mirrors, wherein each current mirror is connected with a summing node through an independent switch;

the first current is connected to the parallel intersection point of the first current mirror group, and the second current is connected to the parallel intersection point of the second current mirror group;

the summing node is connected to an input of the modulator circuit.

3. The variable range temperature sensor according to claim 2,

the first current mirror group at least comprises a first current mirror with a mirror ratio size of 1, the second current mirror group at least comprises a second current mirror with a mirror ratio size of 1, and switches corresponding to the first current mirror and the second current mirror are normally closed;

the first current mirror group at least further comprises a third current mirror with a mirror ratio size of 1, the second current mirror group at least further comprises a fourth current mirror with a mirror ratio size of 1, and the bit stream control signal is used for controlling switches corresponding to the third current mirror and the fourth current mirror;

the measuring range control vector signal is used for controlling switches corresponding to other current mirrors except the first current mirror, the second current mirror, the third current mirror and the fourth current mirror.

4. The variable range temperature sensor of claim 3, wherein said first current mirror group further comprises at least a fifth current mirror, and said second current mirror group further comprises at least a sixth current mirror;

the first current mirror, the third current mirror and the fifth current mirror are all PMOS transistors; the second current mirror, the fourth current mirror and the sixth current mirror are all NMOS transistors;

the grid electrode of the first current mirror is connected with the grid electrode of the third current mirror and the grid electrode of the fifth current mirror and is connected with the first current;

the source electrode of the first current mirror is connected with the source electrode of the third current mirror and the source electrode of the fifth current mirror and is grounded;

the drain of the first current mirror is connected with one end of a first switch, and the other end of the first switch is connected with the summing node;

the drain of the third current mirror is connected with one end of a third switch, and the other end of the third switch is connected with the summing node;

the drain of the fifth current mirror is connected with one end of a fifth switch, and the other end of the fifth switch is connected with the summing node;

correspondingly, the grid electrode of the second current mirror is connected with the grid electrode of the fourth current mirror and the grid electrode of the sixth current mirror and is connected with the second current;

the source electrode of the second current mirror is connected with the source electrode of the fourth current mirror and the source electrode of the sixth current mirror and is grounded;

the drain of the second current mirror is connected with one end of a second switch, and the other end of the second switch is connected with the summing node;

the drain of the fourth current mirror is connected with one end of a fourth switch, and the other end of the fourth switch is connected with the summing node;

and the drain of the sixth current mirror is connected with one end of a sixth switch, and the other end of the sixth switch is connected with the summing node.

5. The variable range temperature sensor of claim 2, wherein the current generating circuit comprises: first PNP triode, second PNP transistor, first resistance, second resistance, third resistance, fourth resistance, first fortune is put, second electric capacity, fourth PMOS transistor, fifth PMOS transistor, sixth PMOS transistor, fourth NMOS transistor, fifth NMOS transistor, sixth NMOS transistor, wherein:

the base stage of the first PNP triode is connected with the collector electrode of the first PNP triode, the base stage of the second PNP triode, the collector electrode of the second PNP triode, one end of the second capacitor, the source electrode of the fifth NMOS transistor and one end of the fourth resistor, and is connected with the ground;

an emitter of the first PNP triode is connected to one end of the first resistor and the positive input end of the first operational amplifier;

the negative input end of the first operational amplifier is connected with one end of the second resistor and one end of the third resistor;

the output end of the first operational amplifier is connected with the grid electrode of the fourth NMOS transistor;

the source of the fourth NMOS transistor is connected with the other end of the first resistor, the other end of the second resistor and the other end of the second capacitor;

the drain of the fourth NMOS transistor is connected with the drain of the fourth PMOS transistor, the grid of the fourth PMOS transistor and the grid of the fifth PMOS transistor;

the source electrode of the fourth NMOS transistor is connected with the source electrode of the fifth PMOS transistor, the source electrode of the sixth PMOS transistor and a power supply;

the drain of the fifth PMOS transistor is connected with the drain of the fifth NMOS transistor and the grid of the fifth NMOS transistor and outputs the first current;

the grid electrode of the sixth PMOS transistor is connected with the drain electrode of the sixth PMOS transistor and the drain electrode of the sixth NMOS transistor and outputs the second current;

the grid electrode of the sixth PMOS transistor is connected with the output end of the second operational amplifier;

the source of the sixth PMOS transistor is connected with the other end of the fourth resistor and the negative input end of the second operational amplifier;

and the positive input end of the second operational amplifier is connected with the emitter of the second PNP triode and the other end of the third resistor.

6. The variable range temperature sensor of claim 1, wherein the modulator circuit comprises: the first capacitor, the third operational amplifier, the comparator and the synchronous circuit;

the third operational amplifier and the first capacitor form an integrating circuit, one end of the first capacitor is connected with the negative input end of the third operational amplifier, the other end of the first capacitor is connected with the output end of the third operational amplifier and the negative input end of the comparator, and the positive input end of the third operational amplifier is connected with an integrating reference voltage corresponding to the measuring current;

the positive input end of the comparator is connected with the threshold voltage of the comparator;

the output end of the comparator is connected with the synchronous circuit, and the synchronous circuit is used for generating the bit stream signal according to the comparison result output by the comparator in the system clock period.

7. The variable range temperature sensor of claim 1, wherein the counter circuit comprises: the device comprises a counting module, a timing module and an output indicating module;

the counting module is used for receiving the bit stream signal and quantizing the duty ratio information in the bit stream signal so as to output binary data corresponding to the measurement result of the temperature to be measured;

the timing module is used for controlling the time period for converting the measuring current and controlling the counting duration of the counting module;

the output indication module is used for resetting the counting module and the timing module after the measuring result is output.

8. The variable range temperature sensor of claim 2, wherein the first current is proportional to an absolute temperature corresponding to the temperature to be measured; the second current is inversely proportional to the absolute temperature corresponding to the temperature to be measured.

9. The variable range temperature sensor of claim 3, wherein the bitstream control signal is determined according to a high-low state of the bitstream signal;

the bit stream control signal is used for controlling switches corresponding to the third current mirror and the fourth current mirror, and specifically includes:

under the condition that the bit stream signal acquired at the end of the last sampling period is at a high level, the corresponding bit stream control signal controls the switch corresponding to the third current mirror to be switched off and controls the switch corresponding to the fourth current mirror to be switched on;

correspondingly, when the bit stream signal obtained at the end of the last sampling period is at a low level, the corresponding bit stream control signal controls the switch corresponding to the third current mirror to be closed, and controls the switch corresponding to the fourth current mirror to be opened.

Technical Field

The invention relates to the technical field of electronic circuits, in particular to a variable range temperature sensor.

Background

The temperature sensor, especially the on-chip temperature sensor, is widely applied to various chip internal designs because of its high integration level, and its basic working principle is: the current inversely proportional to absolute temperature and the current proportional to absolute temperature are generated through a triode and an operational amplifier, the two currents are combined and operated, then the charge and discharge of a capacitor are realized through an integrator, the charge and discharge voltage passes through a comparator, a bit stream signal containing temperature information is generated, the duty ratio of the bit stream signal is proportional to the temperature, and then the bit stream signal which can be sampled and quantized by a digital signal is output after the clock synchronization of a digital domain.

The conventional temperature sensor combines the proportional current and the inverse current according to the following principle: the temperature variation range (temperature measurement range) is corresponding to the whole duty ratio range as much as possible, if the temperature variation range (temperature measurement range) is not full of the temperature variation range, the duty ratio range is low in utilization rate, the quantization digit is fixed, the accuracy required by unit stepping is high, and the design requirement of minimum accuracy cannot be finally realized due to mismatch. In addition, in practical design, in order to avoid process deviation and sampling errors, certain margins are reserved at the positions with the maximum duty ratio and the minimum duty ratio, and only the middle duty ratio range of 80% -90% is used, so that the precision requirement becomes higher, and the realization is more difficult.

Case 1: the traditional temperature sensor with fixed range, for example, the range is-40 to 125 ℃, during actual design, the temperature range is mapped to the whole duty ratio range, and a temperature precision (called precision 1) is correspondingly obtained, if the temperature sensor with fixed range is applied to a scene with a small temperature range, for example, 20 to 50 ℃, because the actual duty ratio change range only occupies about one fifth of the design range, about four fifth of the range is wasted, and only the measurement precision of precision 1 can be realized, so the measurement precision often cannot meet the actual requirement.

Case 2: if the design range of the temperature sensor with the same voltage and the same number of bits is changed to 20-50 ℃, the relatively small temperature range can be mapped to the whole duty ratio range during design, and because the duty ratio range is fixed, a relatively higher and more easily realized measurement accuracy (called accuracy 2) can be obtained in the small temperature range, but the temperature sensor is limited to measure a larger temperature range.

In the two cases, different designs need to be made for different measuring objects and different applications, and different batches of tape-out are performed, so that the manpower resource of the design is wasted, and the tape-out cost is increased.

Disclosure of Invention

In view of the problems in the prior art, embodiments of the present invention provide a variable range temperature sensor, which enables the range of the temperature sensor to have a hot switching function, and can realize free switching among one or several temperature measurement ranges without power interruption.

The invention provides a variable range temperature sensor, comprising: the device comprises a current generating circuit, a range switching circuit, a modulator circuit and a counter circuit. The current generating circuit is used for generating a measuring current according to the temperature to be measured; the range switching circuit is used for converting the measuring current according to a bit stream control signal and a range control vector signal to generate a conversion current; the modulator circuit is used for carrying out analog-to-digital modulation on the conversion current to generate a bit stream signal; and the counter circuit is used for receiving the bit stream signal and outputting the measurement result of the temperature to be measured according to the duty ratio information of the bit stream signal.

According to a variable range temperature sensor provided by the present invention, in a case where the measurement current includes a first current and a second current different from the first current, the range switching circuit includes: the current mirror circuit comprises a first current mirror group consisting of m parallel current mirrors and a second current mirror group consisting of n parallel current mirrors, wherein each current mirror is connected with a summing node through an independent switch; the first current is connected to the parallel intersection point of the first current mirror group, and the second current is connected to the parallel intersection point of the second current mirror group; the summing node is connected to an input of the modulator circuit.

According to the variable range temperature sensor provided by the invention, the first current mirror group at least comprises a first current mirror with a mirror ratio size of 1, the second current mirror group at least comprises a second current mirror with a mirror ratio size of 1, and switches corresponding to the first current mirror and the second current mirror are normally closed; the first current mirror group at least further comprises a third current mirror with a mirror ratio size of 1, the second current mirror group at least further comprises a fourth current mirror with a mirror ratio size of 1, and the bit stream control signal is used for controlling switches corresponding to the third current mirror and the fourth current mirror; the measuring range control vector signal is used for controlling switches corresponding to other current mirrors except the first current mirror, the second current mirror, the third current mirror and the fourth current mirror.

According to the variable range temperature sensor provided by the invention, the first current mirror group at least further comprises a fifth current mirror, and the second current mirror group at least further comprises a sixth current mirror; the first current mirror, the third current mirror and the fifth current mirror are all PMOS transistors; the second current mirror, the fourth current mirror and the sixth current mirror are all NMOS transistors; the grid electrode of the first current mirror is connected with the grid electrode of the third current mirror and the grid electrode of the fifth current mirror and is connected with the first current; the source electrode of the first current mirror is connected with the source electrode of the third current mirror and the source electrode of the fifth current mirror and is grounded; the drain of the first current mirror is connected with one end of a first switch, and the other end of the first switch is connected with the summing node; the drain of the third current mirror is connected with one end of a third switch, and the other end of the third switch is connected with the summing node; the drain of the fifth current mirror is connected with one end of a fifth switch, and the other end of the fifth switch is connected with the summing node; correspondingly, the grid electrode of the second current mirror is connected with the grid electrode of the fourth current mirror and the grid electrode of the sixth current mirror and is connected with the second current; the source electrode of the second current mirror is connected with the source electrode of the fourth current mirror and the source electrode of the sixth current mirror and is grounded; the drain of the second current mirror is connected with one end of a second switch, and the other end of the second switch is connected with the summing node; the drain of the fourth current mirror is connected with one end of a fourth switch, and the other end of the fourth switch is connected with the summing node; and the drain of the sixth current mirror is connected with one end of a sixth switch, and the other end of the sixth switch is connected with the summing node.

According to a variable range temperature sensor provided by the present invention, the current generation circuit includes: first PNP triode, second PNP transistor, first resistance, second resistance, third resistance, fourth resistance, first fortune is put, second electric capacity, fourth PMOS transistor, fifth PMOS transistor, sixth PMOS transistor, fourth NMOS transistor, fifth NMOS transistor, sixth NMOS transistor, wherein: the base stage of the first PNP triode is connected with the collector electrode of the first PNP triode, the base stage of the second PNP triode, the collector electrode of the second PNP triode, one end of the second capacitor, the source electrode of the fifth NMOS transistor and one end of the fourth resistor, and is connected with the ground; an emitter of the first PNP triode is connected to one end of the first resistor and the positive input end of the first operational amplifier; the negative input end of the first operational amplifier is connected with one end of the second resistor and one end of the third resistor; the output end of the first operational amplifier is connected with the grid electrode of the fourth NMOS transistor; the source of the fourth NMOS transistor is connected with the other end of the first resistor, the other end of the second resistor and the other end of the second capacitor; the drain of the fourth NMOS transistor is connected with the drain of the fourth PMOS transistor, the grid of the fourth PMOS transistor and the grid of the fifth PMOS transistor; the source electrode of the fourth NMOS transistor is connected with the source electrode of the fifth PMOS transistor, the source electrode of the sixth PMOS transistor and a power supply; the drain of the fifth PMOS transistor is connected with the drain of the fifth NMOS transistor and the grid of the fifth NMOS transistor and outputs the first current; the grid electrode of the sixth PMOS transistor is connected with the drain electrode of the sixth PMOS transistor and the drain electrode of the sixth NMOS transistor and outputs the second current; the grid electrode of the sixth PMOS transistor is connected with the output end of the second operational amplifier; the source of the sixth PMOS transistor is connected with the other end of the fourth resistor and the negative input end of the second operational amplifier; and the positive input end of the second operational amplifier is connected with the emitter of the second PNP triode and the other end of the third resistor.

According to a variable range temperature sensor provided by the present invention, the modulator circuit comprises: the first capacitor, the third operational amplifier, the comparator and the synchronous circuit; the third operational amplifier and the first capacitor form an integrating circuit, one end of the first capacitor is connected with the negative input end of the third operational amplifier, the other end of the first capacitor is connected with the output end of the third operational amplifier and the negative input end of the comparator, and the positive input end of the third operational amplifier is connected with an integrating reference voltage corresponding to the measuring current; the positive input end of the comparator is connected with the threshold voltage of the comparator; the output end of the comparator is connected with the synchronous circuit, and the synchronous circuit is used for generating the bit stream signal according to the comparison result output by the comparator in the system clock period.

According to a variable range temperature sensor provided by the present invention, the counter circuit includes: the device comprises a counting module, a timing module and an output indicating module; the counting module is used for receiving the bit stream signal and quantizing the duty ratio information in the bit stream signal so as to output binary data corresponding to the measurement result of the temperature to be measured; the timing module is used for controlling the time period for converting the measuring current and controlling the counting duration of the counting module; the output indication module is used for resetting the counting module and the timing module after the measuring result is output.

According to the variable range temperature sensor provided by the invention, the first current is in direct proportion to the absolute temperature corresponding to the temperature to be measured; the second current is inversely proportional to the absolute temperature corresponding to the temperature to be measured.

According to the variable range temperature sensor provided by the invention, the bit stream control signal is determined according to the high-low level state of the bit stream signal; the bit stream control signal is used for controlling switches corresponding to the third current mirror and the fourth current mirror, and specifically includes: under the condition that the bit stream signal acquired at the end of the last sampling period is at a high level, the corresponding bit stream control signal controls the switch corresponding to the third current mirror to be switched off and controls the switch corresponding to the fourth current mirror to be switched on; correspondingly, when the bit stream signal obtained at the end of the last sampling period is at a low level, the corresponding bit stream control signal controls the switch corresponding to the third current mirror to be closed, and controls the switch corresponding to the fourth current mirror to be opened.

The variable range temperature sensor provided by the invention can realize different range switching by changing current combination operation on the chip on the basis of the traditional temperature sensor, has a large range measurement range and high small range measurement precision, expands the application scene of the temperature sensor with extremely low cost, can meet the requirements of small range high precision temperature measurement such as body temperature and the like on the basis of conventional temperature measurement, improves the integration level of a chip, and reduces the area of the chip.

Drawings

In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a variable range temperature sensor provided by the present invention;

FIG. 2 is a schematic diagram of a prior art temperature sensor;

FIG. 3 is a schematic structural view of another variable range temperature sensor provided by the present invention;

FIG. 4 is a schematic diagram of a current generation circuit according to the present invention;

FIG. 5 is a schematic diagram of a modulator circuit provided by the present invention;

FIG. 6 is a schematic diagram of a counter circuit according to the present invention;

wherein the reference numerals are:

100: a current generating circuit; 200: a range switching circuit; 300: a modulator circuit;

400: a counter circuit; 101: a first operational amplifier; 102: a second operational amplifier;

301: a third operational amplifier; 302: a comparator; 303: a synchronization circuit;

401: a counting module; 402: a timing module; 403: and outputting an indication module.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The variable range temperature sensor provided by the embodiment of the invention is described below with reference to fig. 1 to 6.

Fig. 1 is a schematic structural diagram of a variable range temperature sensor provided by the present invention, as shown in fig. 1, including but not limited to: a current generating circuit 100, a span switching circuit 200, a modulator circuit 300, and a counter circuit 400.

The current generation circuit 100 is mainly used for generating a measurement current according to a temperature to be measured; the range switching circuit 200 is mainly configured to convert the measurement current according to a bit stream control signal and a range control vector signal to generate a conversion current; the modulator circuit 300 is mainly configured to perform analog-to-digital modulation on the conversion current to generate a bit stream signal; the counter circuit 400 is mainly configured to receive the bitstream signal and output a measurement result of the temperature to be measured according to duty ratio information of the bitstream signal.

Fig. 2 is a schematic structural view of a temperature sensor in the prior art, and as shown in fig. 2, the temperature sensor in the prior art includes: a current generating circuit, a simple current summing circuit, a sigma-delta modulator circuit, and a counter circuit. The working principle is as follows: the current generated by the current generating circuit is simply summed in a certain proportion and matched with a sigma-delta modulator circuit to form a temperature sensor with a fixed measuring range, and the duty ratio of a generated bit stream signal is in one-to-one correspondence with the temperature. Similar to the temperature sensor shown in fig. 2, all the current temperature sensors adopt a temperature sensing mode with a fixed measuring range, so that different designs are required to be made for different applications, different batches of flow sheets are performed, the manpower resource for design is wasted, and the flow sheet cost is increased.

On the basis of the prior art, the variable-range temperature sensor is provided by the invention. The measurement current is converted into the temperature measurement range by the range switching circuit 200 in a manner of performing combined operation on the measurement current generated by the temperature generation circuit 100, so that the conversion current corresponding to the temperature measurement range is generated, and the switching of the temperature measurement range is realized by changing the magnitude of the current flowing into the modulator circuit 300.

Alternatively, the modulator circuit 300 employed in the present invention may be a delta-sigma analog-to-digital conversion circuit (sigma-delta modulation circuit). The sigma-delta modulation circuit reduces the design requirement on an analog circuit by adopting oversampling, noise shaping and digital filtering technologies, and realizes high precision and low power consumption which cannot be achieved by other types of ADCs.

The range switching circuit 100 converts the detected temperature to be measured into a corresponding measurement current through the temperature sensing element. Alternatively, the measurement current may comprise two types of current signals, such as: one part is a current (called I _ ptat) proportional to the absolute temperature corresponding to the temperature to be measured, and the other part is a current (called I _ be) inversely proportional to the absolute temperature corresponding to the temperature to be measured; or one part of the current is the current proportional to the absolute temperature corresponding to the temperature to be measured, or the current inversely proportional to the absolute temperature corresponding to the temperature to be measured, and the other part of the current is a reference current (such as a constant direct current). That is, in the variable range temperature sensor provided by the present invention, the measurement current generated by the current generation circuit 100 includes two different current signals, but the two current signals carry the temperature information of the temperature to be measured.

Further, an input terminal of the range switching circuit 200 is connected to the current output terminal of the current generating circuit 100, and is used for receiving the measurement current generated by the current generating circuit 100.

Specifically, as shown in fig. 1, a range switching circuit 200, which is preset according to the temperature measurement range, performs a combination operation on the received measurement currents, and outputs corresponding conversion currents.

Further, the output of the range switching circuit 200 is connected to the input of the modulator circuit 300. The modulator circuit 300 modulates the received converted current (mainly including analog-to-digital conversion) and outputs a bit stream signal containing temperature information of the temperature to be measured.

Wherein a high level duty cycle of the bitstream signal contains the temperature information. For example: the higher the high-level duty ratio obtained in one adopted period is, the higher the corresponding temperature to be measured is.

Further, in order to accurately measure and read the temperature, the variable range temperature sensor further includes a counter circuit 400, wherein an input terminal of the counter circuit 400 is connected to an output terminal of the modulator circuit 300, and is configured to quantize the input bitstream signal and output a binary signal containing the temperature information. And finally, converting the binary signal into a corresponding measurement result and outputting the measurement result.

It should be noted that the current generating circuit 100, the modulator circuit 300, and the counter circuit 400 of the present invention may all use conventional circuits in the prior art to perform corresponding functions, and are not described in detail herein.

Compared with the prior art, the variable range temperature sensor provided by the invention is mainly characterized by further comprising a range switching circuit 200, wherein the measuring current output by the current generating circuit 100 can be correspondingly converted according to the bit flow control signal and the range control vector signal and the temperature measuring range, and the switching of the temperature measuring range is realized by changing the magnitude of the current flowing into the modulator circuit.

Wherein the bit stream control signal is determined by the bit stream signal outputted by the modulator circuit 300 in the last adopted period, so as to determine that the range switching circuit 300 is in the reset state in the current adopted period according to the bit stream signal in the last adopted period.

For example, at the end of the previous sampling period, the bit stream signal is at a high level, and at this time, the two switches of the element for current conversion corresponding to the bit stream control signal are respectively the switch SW1 being closed and the switch SW2 being open; the switch SW1 is turned off and the switch SW2 is turned on according to the bit stream control signal in the current sampling period.

The measuring range control vector signal can be input from the outside, and the working state of each element in the measuring range switching circuit is changed, so that the measuring current is converted in equal proportion according to different measuring ranges, and the corresponding conversion current is output.

The variable range temperature sensor provided by the invention can realize different range switching by changing current combination operation on the chip on the basis of the traditional temperature sensor, has a large range measurement range and high small range measurement precision, expands the application scene of the temperature sensor with extremely low cost, can meet the requirements of small range high precision temperature measurement such as body temperature and the like on the basis of conventional temperature measurement, improves the integration level of a chip, and reduces the area of the chip.

Based on the content of the foregoing embodiment, as an alternative embodiment, in the case that the measurement current includes a first current and a second current different from the first current, the range switching circuit 200 includes: the current mirror circuit comprises a first current mirror group consisting of m parallel current mirrors and a second current mirror group consisting of n parallel current mirrors, wherein each current mirror is connected with a summing node through an independent switch; the first current is connected to the parallel intersection point of the first current mirror group, and the second current is connected to the parallel intersection point of the second current mirror group; the summing node is connected to an input of the modulator circuit.

Specifically, as shown in fig. 1, in the variable range temperature sensor provided by the present invention, the current conversion function of the range switching circuit 200 is mainly realized by a current mirror.

The current mirror, also called as a mirror constant current source, is used for generating a bias current and is used as an active load, and is a standard component commonly existing in an analog integrated circuit.

Specifically, in the variable range temperature sensor provided by the invention, a first current mirror group is formed by connecting m current mirrors in parallel, such as I in fig. 1₁、I₃、I₅、I₇…I_n(ii) a At the same time, n current mirrors are connected in parallel to form a second current mirror group, as shown in I in FIG. 1₂、I₄、I₆、I₈…I_m. Each current mirror can be regarded as a current source having a certain proportion (i.e. current transfer ratio) to the input current, and therefore, the current mirrors are referred to as a first current source, a second current source, a third current source, a fourth current source, a fifth current source, a sixth current source, a seventh current source, an eighth current source, … …, an mth current source, and an nth current source, respectively, according to the reference numerals of the current mirrors in fig. 1. Where each current source is connected through a switch to a summing node connected to the input of the modulator circuit 300.

Further, the parallel intersection of all current sources in the first current mirror group is connected to a first current (e.g. I _ ptat) in said measurement current, and the parallel intersection of all current sources in the second current mirror group is connected to a first current (e.g. I _ be) in said measurement current. On the basis, all current sources of the first current mirror group are used for charging the summing node according to the input I _ ptat; all current sources of the second current mirror group are used for discharging to the summing node according to the input I _ be.

Finally, the modulator circuit outputs a corresponding bit stream signal to the received measuring current (the measuring current can be determined by the combination operation of the I _ ptat and the I _ be generated by the current generation circuit).

The range switching circuit provided by the invention can realize the conversion of the measuring current, and is mainly represented by the following steps: the on-off of each switch can be controlled according to the bit stream control signal and the range control vector signal to control the on-off between each current source and the summing node, so that the magnitude of the conversion current input to the modulator circuit 300 is controlled, and the range switching is realized.

The variable range temperature sensor provided by the invention utilizes a plurality of current mirrors to form a current mirror group, realizes the adjustment of the input measuring current by controlling whether the current of each current mirror is output to a modulator circuit or not, provides a method for scientifically and accurately converting the current containing temperature information by changing the current combination operation on a chip according to the requirements of different temperature measuring ranges, has strong controllability and simple operation, and expands the application scene of the temperature sensor with extremely low cost.

Based on the content of the foregoing embodiment, as an optional embodiment, the first current mirror group at least includes a first current mirror with a mirror ratio size of 1, the second current mirror group at least includes a second current mirror with a mirror ratio size of 1, and switches corresponding to the first current mirror and the second current mirror are normally closed; the first current mirror group at least further comprises a third current mirror with a mirror ratio size of 1, the second current mirror group at least further comprises a fourth current mirror with a mirror ratio size of 1, and the bit stream control signal is used for controlling switches corresponding to the third current mirror and the fourth current mirror; the measuring range control vector signal is used for controlling switches corresponding to other current mirrors except the first current mirror, the second current mirror, the third current mirror and the fourth current mirror.

Based on the content of the foregoing embodiments, as an alternative embodiment, the first current mirror I with the mirror scale size of 1 may be selected₁A second current mirror I₂A third current mirror I₃And a fourth current mirror I₄Wherein the first current mirror I₁And a second current mirror I₃Is identical to the second current mirror I₂And a fourth current mirror I₄The current direction of (2) is opposite.

Wherein, the first current mirror I₁A second current mirror I₂The corresponding switch is in a normally-closed state, and the third current mirror I₃The fourth current mirror I₄The corresponding switch state isIn contrast, i.e. in the fourth current mirror I₄When the corresponding switch is closed, the third current mirror I₃The corresponding switch is disconnected; at the fourth current mirror I₄When the corresponding switch is turned off, the third current mirror I₃The corresponding switch is closed.

In the case where I _ ptat is all charged to the summing node and I _ be is all discharged to the summing node, the calculation formula of the duty ratio of the bit stream signal is:

where k1 is the sum of the mirror scale sizes of all the current mirrors charging the summing node and k2 is the sum of the mirror scale sizes of all the current mirrors discharging the summing node.

Therefore, the variable range temperature sensor provided by the invention is used for measuring the temperature of the first current mirror I₁A second current mirror I₂A third current mirror I₃And a fourth current mirror I₄The corresponding switch is arranged as above, so that the reference duty ratio can be obtained, and the calibration operation of the whole variable range temperature sensor can be realized according to the reference duty ratio at the later stage.

Based on the content of the foregoing embodiments, as an optional embodiment, the first current mirror group further includes at least a fifth current mirror PMOS3, and the second current mirror group further includes at least a sixth current mirror NMOS 3;

the first current mirror PMOS1, the third current mirror PMOS2, and the fifth current mirror PMOS3 are all PMOS transistors; the second current mirror NMOS1, the fourth current mirror NMOS2, and the sixth current mirror NMOS3 are all NMOS transistors;

the gate of the first current mirror PMOS1 is connected to the gate of the third current mirror PMOS2 and the gate of the fifth current mirror PMOS3, and is connected to the first current I _ ptat;

the source of the first current mirror PMOS1 is connected to the source of the third current mirror PMOS2 and the source of the fifth current mirror PMOS3, and is grounded;

the drain of the first current mirror PMOS1 is connected with one end of a first switch SW1, and the other end of the first switch SW1 is connected with the summation node;

the drain of the third current mirror PMOS2 is connected to one end of a third switch SW3, and the other end of the third switch SW3 is connected to the summing node;

the drain of the fifth current mirror PMOS3 is connected to one end of a fifth switch SW5, and the other end of the fifth switch SW5 is connected to the summing node;

correspondingly, the gate of the second current mirror NMOS1 is connected to the gate of the fourth current mirror NMOS2 and the gate of the sixth current mirror NMOS3, and is connected to the second current I _ be;

the source of the second current mirror NMOS1 is connected to the source of the fourth current mirror NMOS2 and the source of the sixth current mirror NMOS3, and is grounded;

the drain of the second current mirror NMOS1 is connected to one end of a second switch SW2, and the other end of the second switch SW2 is connected to the summing node;

a drain of the fourth current mirror NMOS2 is connected to one end of a fourth switch SW4, and the other end of the fourth switch SW4 is connected to the summing node;

and the drain of the sixth current mirror is connected with one end of a sixth switch, and the other end of the sixth switch is connected with the summing node.

Fig. 3 is a schematic structural view of another variable-range temperature sensor according to the present invention, as shown in fig. 3, as an alternative embodiment,

specifically, the range switching circuit in this embodiment includes: a first current mirror PMOS1, a second current mirror NMOS1, a third current mirror PMOS2, a fourth current mirror NMOS2, a fifth current mirror PMOS3, a sixth current mirror NMOS3, a first switch SW1, a second switch SW2, a third switch SW3, a fourth switch SW4, a fifth switch SW5, and a sixth switch SW 6. Wherein:

the grid voltage of the first current mirror PMOS1 is connected with the mirror image voltage of the current signal I _ ptat which is in direct proportion to the absolute temperature, the source electrode is grounded, and the drain electrode is connected with one end of the second switch SW 2;

the grid voltage of the fourth current mirror NMOS2 is connected with the mirror image voltage of the current signal I _ ptat which is in direct proportion to the absolute temperature, the source electrode is grounded, the drain electrode is connected with one end of the fourth switch SW4, and the fourth current mirror NMOS2 and the second current mirror NMOS1 belong to the same group of current mirrors;

the gate voltage of the sixth current mirror NMOS3 is connected to the mirror voltage of the current signal proportional to the absolute temperature, the source is grounded, the drain is connected to one end of the sixth switch SW6, and the sixth current mirror NMOS3 and the fourth current mirror NMOS2 belong to the same group of current mirrors.

The grid voltage of the first current mirror PMOS1 is connected with the mirror voltage of the current signal inversely proportional to the absolute temperature, the source is connected with the power supply, and the drain is connected with one end of the first switch SW 1;

the grid voltage of the third current mirror PMOS2 is connected with the mirror image voltage of the current signal I _ be inversely proportional to the absolute temperature, the source electrode is connected with the power supply, the drain electrode is connected with one end of the third switch SW3, and the third current mirror PMOS2 and the first current mirror PMOS1 belong to the same group of current mirrors;

the grid voltage of the fifth current mirror PMOS3 is connected with the mirror image voltage of the current signal I _ be inversely proportional to the absolute temperature, the source electrode is connected with the power supply, the drain electrode is connected with one end of the fifth switch SW5, and the fifth current mirror PMOS3, the third current mirror PMOS2 and the first current mirror PMOS1 belong to the same group of current mirrors;

one end of the first switch SW1 is connected with the current summing node, and the other end of the first switch SW1 is connected with the drain electrode of the first current mirror PMOS 1;

one end of the second switch SW2 is connected with the current summing node, and the other end is connected with the drain electrode of the second current mirror NMOS 1;

one end of the third switch SW3 is connected with the current summing node, and the other end of the third switch SW3 is connected with the third current mirror PMOS 2;

one end of the fourth switch SW4 is connected with the current summing node, and the other end of the fourth switch SW4 is connected with the drain electrode of the fourth current mirror NMOS 2;

one end of the fifth switch SW5 is connected to the current summing node, and the other end is connected to the drain of the fifth current mirror PMOS 3;

one end of the sixth switch SW6 is connected to the current summing node, and the other end is connected to the sixth current mirror NMOS 3.

In the variable range temperature sensor provided by the invention, the range switching circuit 200 mainly comprises a series of PMOS and NMOS transistors and corresponding switches, the transistors are current mirrors, the current I _ ptat inversely proportional to absolute temperature and the current I _ be directly proportional to absolute temperature in the mirror current generation circuit 100 are mirrored, and the mirror proportional size is calculated according to the required range. In the scale switching circuit 200, the NMOS transistor flows a current that is a multiple of I _ ptat, and the PMOS transistor flows a current that is a multiple of I _ be.

Based on the above circuit, the first switch SW1 and the second switch are controlled by two signals opposite to each other, which are the output bitstream signal Bit _ Stream of the sigma-delta modulator circuit 200. The third switch SW3 and the fourth switch SW4 are normally on states in the present invention; the fifth switch SW5, the sixth switch SW6, the mth switch SWm and the nth switch SWn are controlled by a range control vector signal, the range control vector signal is a range switching control signal, after the fifth switch, the sixth switch, the mth switch and the nth switch are controlled and closed according to vector combination, the fifth current mirror PMOS3, the sixth current mirror NMOS3, the mth current mirror and the nth current mirror are connected to a current summing node, the number of the third current mirror PMOS2 and the number of the fourth current mirror NMOS2 can be equivalently changed, equivalent is a current combination operation formula change, and therefore range switching is achieved.

As a specific embodiment, in the range switching circuit, a mirror ratio size of the first PMOS transistor is 1, a mirror ratio size of the second PMOS transistor is 1, a mirror ratio size of the third PMOS transistor is 5, a mirror ratio size of the first NMOS transistor is 1, a mirror ratio size of the second NMOS transistor is 1, a mirror ratio size of the third NMOS transistor is 6, the mirror ratio sizes are calculated according to a range of-40 to 125 ℃ and a range of 20 to 50 ℃, and a duty ratio formula corresponding to the two temperature measurement ranges is as follows:

it can be seen that the denominator I _ ptat + I _ be is a temperature-independent current, the numerator combination is a temperature-dependent value, and the duty ratios obtained by different combination operations are different, thereby realizing different application ranges.

Based on the above principle analysis, those skilled in the art should understand that different design ranges may correspond to different combination operation forms, and in the embodiment, only the switching of two specific ranges is illustrated, and in practical application, many different range switching may be designed according to the situation.

It should be noted that, in the specific application of the present invention, the mirror scale sizes of the m + n current mirrors are respectively fixed, but in other range applications, different current mirror scales may be adopted to implement different combination operations according to actual calculation requirements, and various current mirror scales are included in the protection scope of the present invention, that is, the present invention does not specifically limit the mirror scale size of each current mirror.

Fig. 4 is a schematic structural diagram of a current generating circuit 100 according to an embodiment of the present invention, and as shown in fig. 4, the current generating circuit 100 mainly includes: the first PNP triode PNP1, the second PNP transistor PNP2, the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the first operational amplifier 101, the second operational amplifier 102, the second capacitor C2, the fourth PMOS transistor PMOS4, the fifth PMOS transistor PMOS5, the sixth PMOS transistor PMOS6, the fourth NMOS transistor NMOS4, the fifth NMOS transistor NMOS5, and the sixth NMOS transistor NMOS 6.

Wherein the base of the first PNP transistor PNP1 is connected to the collector of the first PNP transistor PNP1, the base of the second PNP transistor PNP2, the collector of the second PNP transistor PNP2, one end of the second capacitor C2, the source of the fifth NMOS transistor NMOS5, and one end of the fourth resistor R4, and is connected to ground;

an emitter of the first PNP transistor PNP1 is connected to one end of the first resistor R1 and the positive input end of the first operational amplifier 101;

the negative input end of the first operational amplifier 101 is connected with one end of the second resistor R2 and one end of the third resistor R3;

the output end of the first operational amplifier 101 is connected with the gate NMOS4 of the fourth NMOS transistor;

the source of the fourth NMOS transistor NMOS4 is connected with the other end of the first resistor R1, the other end of the second resistor R2 and the other end of the second capacitor C2;

a drain of the fourth NMOS transistor NMOS4 is connected to a drain of the fourth PMOS transistor PMOS4, a gate of the fourth PMOS transistor PMOS4, and a gate of the fifth PMOS transistor PMOS 5;

the source of the fourth NMOS transistor NMOS4 is connected with the source of the fifth PMOS transistor PMOS5, the source of the sixth PMOS transistor PMOS6 and is connected with a power supply;

the drain of the fifth PMOS transistor PMOS5 is connected to the drain of the fifth NMOS transistor NMOS5 and the gate of the fifth NMOS transistor NMOS5, and outputs the first current I _ ptat;

the gate of the sixth PMOS transistor PMOS6 is connected to the drain of the sixth PMOS transistor PMOS6 and the drain of the sixth NMOS transistor NMOS6, and outputs the second current I _ be;

the gate of the sixth PMOS transistor PMOS6 is connected to the output terminal of the second operational amplifier 102;

the source of the sixth PMOS transistor PMOS6 is connected to the other end of the fourth resistor R4 and the negative input end of the second operational amplifier 102;

the positive input terminal of the second operational amplifier 102 is connected to the emitter of the second PNP transistor PNP2 and the other terminal of the third resistor R3.

It should be noted that the current generating circuit 100 provided in the present invention is a specific embodiment, and other current generating circuits may be adopted, which essentially need to generate a current proportional to absolute temperature and a current inversely proportional to absolute temperature, or a current combining the two currents for the subsequent range switching circuit to perform the combination operation.

Fig. 5 is a schematic structural diagram of a modulator circuit 300 provided in the present invention, and as shown in fig. 5, the modulator circuit 300 mainly includes: a first capacitor C1, a third operational amplifier 301, a comparator 302 and a synchronization circuit 303.

The third operational amplifier 301 and the first capacitor C1 form an integrated circuit, one end of the first capacitor C1 is connected to the negative input terminal of the third operational amplifier 301, the other end of the first capacitor C1 is connected to the output terminal of the third operational amplifier 301 and the negative input terminal of the comparator 302, and the positive input terminal of the third operational amplifier 301 is connected to an integrated reference voltage REF corresponding to the measurement current;

the positive input end of the comparator 302 is connected to a comparator threshold voltage VTH;

the output terminal of the comparator 302 is connected to the synchronization circuit 303, and the synchronization circuit 303 is configured to generate the bitstream signal Bit _ Stream according to the comparison result output by the comparator 302 in a system clock cycle.

It should be noted that, the present invention provides a sigma-delta modulator circuit, and optionally, other modulator circuits may also be used, and the other modulator circuits may make appropriate changes in structure according to actual use situations, and essentially need to integrate the currents after the combined operation by an integrator, and then compare the integrated currents by a comparator, and output a bitstream signal Bit _ Stream whose duty cycle includes temperature information, and the synchronization circuit 303 is configured to synchronously generate the bitstream signal Bit _ Stream by using a system clock, so as to facilitate the subsequent quantization by using the counter circuit 400, so as to reduce the sampling error.

Fig. 6 is a schematic structural diagram of a counter circuit 400 provided in the present invention, and as shown in fig. 6, the counter circuit 400 mainly includes: a counting module 401, a timing module 402 and an output indication module 403;

the counting module 401 is mainly configured to receive the bitstream signal and quantize the duty ratio information in the bitstream signal to output binary data corresponding to the measurement result of the temperature to be measured; the timing module 402 is mainly used for controlling a time period for converting the measurement current and controlling a counting duration of the counting module; the output indication module 403 is mainly configured to reset the counting module 401 and the timing module 402 after outputting the measurement result.

Specifically, the counting module 401 is configured to quantize bitstream information output by the pre-stage sigma-delta modulator circuit 300, and extract temperature information.

The timing module 402 is used to control the setup time of the sigma-delta modulator circuit 300 and the counting duration of the counting module 401.

The output indication module 403 is used to inform the next stage that the output is ready after the counting is completed, and reset the timing module 402 and the counting module 401 after a certain period of time, so as to start a new round of detection.

It should be noted that the counter circuit 400 provided by the present invention is the most specific embodiment, and other counter circuits may also be adopted, and the structures of the other counter circuits may be changed according to the actual use situation, for example, on the basis of the circuit structure shown in fig. 6, if the output bit number needs to be changed, the timing duration may be changed accordingly, and the like.

Based on the content of the foregoing embodiment, as an optional embodiment, the first current is proportional to an absolute temperature corresponding to the temperature to be measured; the second current is inversely proportional to the absolute temperature corresponding to the temperature to be measured.

According to the variable range temperature sensor provided by the invention, the current generation circuit 100 is utilized to directly generate the I _ ptat which is in direct proportion to the absolute temperature corresponding to the temperature to be measured and the I _ be which is in inverse proportion to the absolute temperature corresponding to the temperature to be measured, so that a range control vector signal can be reasonably configured by the range switching circuit 200 according to the temperature measurement range at a later stage, the input current is modulated to generate the measurement current, and the accuracy of range switching is effectively improved.

Based on the content of the foregoing embodiment, as an alternative embodiment, the bitstream control signal is determined according to the high-low state of the bitstream signal; the bit stream control signal is used for controlling switches corresponding to the third current mirror and the fourth current mirror, and specifically includes: under the condition that the bit stream signal acquired at the end of the last sampling period is at a high level, the corresponding bit stream control signal controls the switch corresponding to the third current mirror to be switched off and controls the switch corresponding to the fourth current mirror to be switched on; correspondingly, when the bit stream signal obtained at the end of the last sampling period is at a low level, the corresponding bit stream control signal controls the switch corresponding to the third current mirror to be closed, and controls the switch corresponding to the fourth current mirror to be opened.

According to the variable-range temperature sensor, on the basis of realizing the configuration of the range switching circuit by using the range control vector signal, the bit stream control signal is generated according to the high and low level states of the bit stream signal, so that the generated test quantity current is rectangular wave current, a foundation is provided for a later counter circuit to quantize the duty ratio of the bit stream signal, and the measurement precision is effectively improved.

In summary, the variable range temperature sensor provided by the invention creatively provides the range switching circuit to match with the corresponding sigma-delta modulator circuit, so that the range of the temperature sensor has a hot switching function, and can be freely switched in one or more groups of temperature measurement ranges under the condition of no power failure. The design mode has the advantages that the increase of the area of the chip is very small, the application scene of the temperature sensor chip is expanded at very low cost, the integration level of the chip is improved, and the cost increased by multi-version differentiation is saved.

The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute various embodiments or some portions of embodiments described above.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.