A digital temperature sensor and chip

Abstract

The present application discloses a digital temperature sensor, including a front-end analog circuit and a quantization circuit, wherein the front-end analog circuit is used to sense temperature and output a first electrical signal and a second electrical signal containing temperature information, and the quantization circuit is used to input the first electrical signal and the second electrical signal output by the front-end analog circuit, and obtain a positive temperature signal positively correlated with temperature and a negative temperature signal negatively correlated with temperature based on the first electrical signal and the second electrical signal, and gradually approach the other by multiplying the product of the temperature coefficient of the positive temperature signal and the negative temperature signal with a smaller absolute value by the temperature information N, or gradually approaching the other by dividing the temperature coefficient of the positive temperature signal and the negative temperature signal with a larger absolute value by the temperature information N, thereby obtaining quantized temperature information N, thereby realizing the detection and quantization output of temperature without using a high-precision ADC. The present application also provides a chip, including the above-mentioned digital temperature sensor.

Description

Technical Field

[0001] The present application relates to the field of temperature detection, and in particular to a digital temperature sensor and a chip including the digital temperature sensor. Background Art

[0002] Temperature sensors are used to measure the temperature of the object being measured. They can be divided into two types according to the implementation method: analog and digital. With the increasing maturity of artificial intelligence, the intelligence of sensors has become inevitable, and the use of digital temperature sensors has become more and more extensive.

[0003] The basic principle of digital temperature sensor is to extract temperature information through voltage (or current) related to temperature, and then convert the continuous analog signal into a discrete digital signal through a high-precision analog-to-digital converter (ADC) to realize the digital quantization of temperature information, and finally convert the quantized value into temperature value output.

[0004] With the development of artificial intelligence, the scale of complex chips such as GPU, FPGA, CPU and accelerator is getting larger and larger. It is becoming more and more important to monitor the local temperature of the chip by designing digital temperature sensors on the chip to optimize chip power consumption and ensure reliable operation of the chip. However, the current digital temperature sensors require high-precision ADCs to ensure the accuracy of temperature measurement, which means that the chip area and power consumption of the ADC will be relatively large. Summary of the invention

[0005] The present application provides a digital temperature sensor that does not require a high-precision analog-to-digital converter, but instead uses a relatively simple method to achieve temperature measurement.

[0006] According to one aspect of the present application, in one embodiment, a digital temperature sensor is provided, comprising a front-end analog circuit and a quantization circuit for reading out quantized temperature information, wherein the front-end analog circuit is used to sense temperature and output a first electrical signal and a second electrical signal containing temperature information; the quantization circuit is connected to the front-end analog circuit, and is used to input the first electrical signal and the second electrical signal output by the front-end analog circuit, and obtain a positive temperature signal positively correlated with temperature and a negative temperature signal negatively correlated with temperature based on the first electrical signal and the second electrical signal, and output quantized temperature information N based on the positive temperature signal and the negative temperature signal, wherein the value of the temperature information N is a positive integer when the product of the positive temperature signal and the negative temperature signal with a smaller absolute value of the temperature coefficient multiplied by the temperature information N is closest to the other, or the value of the temperature information N is a positive integer when the quotient of the positive temperature signal and the negative temperature signal with a larger absolute value of the temperature coefficient divided by the temperature information N is closest to the other.

[0007] In one embodiment, the quantization circuit includes:

[0008] A transformation unit, used to multiply the one with the smaller absolute value of the temperature coefficient of the positive temperature signal and the negative temperature signal by the continuously accumulated temperature information N, and obtain a product that increases successively; or used to divide the one with the larger absolute value of the temperature coefficient of the positive temperature signal and the negative temperature signal by the continuously accumulated temperature information N, and obtain a quotient that decreases successively;

[0009] A comparator, configured to output a first level when the successively increasing product or the successively decreasing quotient does not approach the other, and output a second level when the product or the successively decreasing quotient approaches the other;

[0010] The accumulator is used to set the initial value of the temperature information N to 1, and accumulate N following the clock cycle based on the first level output by the comparator, and output the accumulated N to the transformation unit. The accumulator stops accumulating N when the comparator outputs the second level, and outputs N after stopping accumulation as the quantized temperature information.

[0011] According to the second aspect, an embodiment provides a chip, including a chip substrate for implementing a preset operation or processing function, and a plurality of the above-mentioned digital temperature sensors are distributed on the chip substrate.

[0012] According to the above embodiment, the quantization circuit obtains a positive temperature signal positively correlated with temperature and a negative temperature signal negatively correlated with temperature based on the first electrical signal and the second electrical signal, and gradually approaches the other by multiplying the one with the smaller absolute value of the temperature coefficient of the positive temperature signal and the negative temperature signal by the continuously accumulated temperature information N, or gradually approaches the other by dividing the one with the larger absolute value of the temperature coefficient of the positive temperature signal and the negative temperature signal by the quotient of the continuously accumulated temperature information N, thereby obtaining N when it is closest to the other, and outputting N at this time as quantized temperature information. The solution of the present application realizes the detection of temperature without using a high-precision ADC, and the device used in the solution of the present application is simple, which can reduce the occupied area and power consumption of the digital temperature sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of the structure of a digital temperature sensor in an embodiment;

[0014] Figure 2 This is the principle block diagram of the quantization circuit;

[0015] Figure 3 is a circuit structure diagram of a quantization circuit in an embodiment;

[0016] Figure 4 A clock timing diagram of an approximate difference unit in an embodiment;

[0017] Figure 5 It is a graph showing the change of the quantitative value with temperature;

[0018] Figure 6 A circuit diagram of a front-end analog circuit in another embodiment;

[0019] Figure 7 A circuit structure diagram of a quantization circuit in another embodiment;

[0020] Figure 8 FIG. 4 is a schematic diagram of a multi-point distribution of digital temperature sensors in a chip in an embodiment. DETAILED DESCRIPTION

[0021] The present application is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are intended to enable the present application to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, and methods. In some cases, some operations related to the present application are not shown or described in the specification, in order to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0022] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations, and the operation steps involved in each embodiment can also be replaced or adjusted in a sequence in a manner that is obvious to those skilled in the art. Therefore, the specification and drawings are only for the purpose of clearly describing a certain embodiment and do not mean that the composition and / or sequence are necessary.

[0023] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0024] Please refer to Figure 1 The temperature sensor includes a front-end analog circuit 10, a quantization circuit 20 and a digital processing circuit 30. The front-end analog circuit 10 includes a temperature sensing element for sensing temperature changes and outputting an electrical signal containing temperature information, such as a current signal or a voltage signal. The temperature information is usually extracted through an electrical signal that meets the following conditions:

[0025] 1) There are two voltage quantities that are strongly related to temperature;

[0026] 2) These two voltage quantities vary monotonically with temperature within the measurement temperature range;

[0027] 3) The temperature coefficients of these two voltage quantities vary little within the measurement temperature range, that is, the linearity is better.

[0028] In one embodiment, the characteristics of the on-chip semiconductor device and its temperature-related characteristics are utilized to use a bipolar transistor formed by a CMOS process as a temperature sensing element, and the base-emitter voltage V BE and the V of the two bipolar transistors BE The difference ΔV BE All three conditions above are met, and the base-emitter voltage V BE Negatively related to temperature, the V BE The difference ΔV BE Positively correlated with temperature. Currently, the most common way to implement digital temperature sensors is to quantify the ratio between the two voltages that are strongly correlated with temperature. The common quantization target is X or Y, as shown in the following formula.

[0029] ………………………………………………(1)

[0030] According to the above formula, the curve of X changing with temperature or the quantitative curve of Y changing with temperature can be measured in advance. When measuring temperature, as long as V BE and ΔV BE The ratio between the two can be obtained by checking the quantitative curve to get the value of temperature T.

[0031] When an ADC is used to quantize X or Y, a high-precision ADC will occupy a large chip area and consume a large amount of energy.

[0032] During the research, the inventors found that the requirements for chip internal temperature monitoring are quite different from those of traditional temperature sensors, as follows:

[0033] 1) The temperature measurement accuracy requirement is relatively low and can be relaxed to ±10 o C Error range;

[0034] 2) The chip area occupied should be small;

[0035] 3) The power consumption should be small.

[0036] Therefore, the inventors have conceived of detecting the internal temperature of the chip by using a temperature sensor that does not use a high-precision ADC, thereby avoiding the defects caused by using a high-precision ADC. In order not to use a high-precision ADC for quantization, the invention is to calculate the following formula:

[0037] M=V BE -N*ΔV BE ………………………………………………(2)

[0038] Ideally, when M=0, N= V BE / ΔV BE , which is the same as the general quantitative target X. Therefore, the further concept of the invention is to find a method that can make N*ΔV BE As close to V as possible BE N, for example, by continuously performing +1 iterations of N, to find the value that makes N*ΔV BE As close to V as possible BE N, at this time, the M value obtained by formula (2) is close to the quantization target X value. When the temperature measurement accuracy requirement is not high, the temperature value T01 obtained by querying the quantization curve based on the M value can be used as the measured temperature value.

[0039] The technical solution for realizing the inventive concept is described below.

[0040] Embodiment 1:

[0041] Please refer to Figure 1 As shown, the temperature sensor of this embodiment includes a front-end analog circuit 10, a quantization circuit 20 and a digital processing circuit 30. The front-end analog circuit 10 includes two current sources and two bipolar transistors. The current of the second current source PI is P times that of the first current source I. The currents provided by the two current sources flow through the two transistors respectively, and the base-emitter voltages of the two transistors are output as the first electrical signal V BEL and the second electrical signal V BER In this embodiment, the first electrical signal V BEL and the second electrical signal V BER are all signals that are negatively correlated with temperature, that is, the first electrical signal V BEL and the second electrical signal V BER Both decrease with increasing temperature, but the first electrical signal V BEL and the second electrical signal V BER The difference ΔV BE is a signal positively correlated with temperature, and the first electrical signal V BEL and the second electrical signal V BER The absolute value of the negative temperature coefficient is greater than ΔV BE The absolute value of the positive temperature coefficient.

[0042] The quantization circuit 20 is used to quantize the analog electrical signal output by the front-end analog circuit 10. The input end of the quantization circuit 20 is connected to the output end of the front-end analog circuit 10 and is used to input the first electrical signal V BEL and the second electrical signal V BER In order to achieve quantization, a positive temperature signal positively correlated with temperature and a negative temperature signal negatively correlated with temperature need to be obtained. The quantization circuit 20 is based on the first electrical signal V BELand the second electrical signal V BER A positive temperature signal positively correlated with temperature and a negative temperature signal negatively correlated with temperature are obtained, and then quantized temperature information N is output based on the positive temperature signal and the negative temperature signal. The value of the temperature information N is a positive integer when the product of the positive temperature signal and the negative temperature signal with a smaller absolute value of the temperature coefficient multiplied by the temperature information N is closest to the other, or the value of the temperature information N is a positive integer when the quotient of the positive temperature signal and the negative temperature signal with a larger absolute value of the temperature coefficient divided by the temperature information N is closest to the other.

[0043] The digital processing circuit 30 is connected to the quantization circuit 20 and is used to output a temperature value based on the quantized temperature information output by the quantization circuit 20 .

[0044] In some embodiments, the digital processing circuit 30 is not necessary, and the temperature information N output by the quantization circuit 20 can also be used as the output temperature value of the digital temperature sensor, but the relationship between the value of N and the actual temperature is not linear. Please refer to Figure 5 , need to check Figure 5 The digital processing circuit 30 is used to process the N value accordingly, so that the final temperature information output value is linearly related to the actual temperature.

[0045] The principle block diagram of the quantization circuit 20 based on the concept of the present invention is as follows Figure 2 As shown, the quantization circuit includes a conversion unit D1, a comparator D3 and an accumulator D4. The conversion unit D1 is used to multiply the one with the smaller absolute value of the temperature coefficient of the positive temperature signal and the negative temperature signal by the continuously accumulated temperature information N, and obtain a product that increases successively; or to divide the one with the larger absolute value of the temperature coefficient of the positive temperature signal and the negative temperature signal by the continuously accumulated temperature information N, and obtain a quotient that decreases successively. The comparator D3 is used to output a first level when the successively increasing product or the successively decreasing quotient does not reach the closest to the other, and output a second level when it reaches the closest to the other. The accumulator D4 is used to set the initial value of the temperature information N to 1, and accumulate N based on the first level output by the comparator following the clock cycle, and the accumulated N is output to the conversion unit D1 to obtain a product that increases successively or a quotient that decreases successively. The accumulator D4 stops accumulating N when the comparator D3 outputs the second level, and outputs the N after stopping accumulation as the quantized temperature information.

[0046] The two quantities that the quantization circuit needs to compare are the positive temperature signal and the negative temperature signal. BEL and the second electrical signal V BER As an example, the first electrical signal V BEL and the second electrical signal V BER are all signals that are negatively correlated with temperature, and the first electrical signal V BEL and the second electrical signal VBER The difference ΔV BE is a positive temperature signal, therefore, the first electrical signal V BEL and the second electrical signal V BER One of the two is used as a negative temperature signal, and the first electrical signal V is selected BEL and the second electrical signal V BER The difference ΔV BE As a positive temperature signal, Figure 2 V BE Indicates negative temperature signal, using ΔV BE = represents a positive temperature signal. Since the absolute value of the temperature coefficient of the negative temperature signal is greater than the absolute value of the temperature coefficient of the positive temperature signal, in one embodiment, ΔV is compared. BE Multiplying by the accumulated temperature information N is close enough to V BE For example, ΔV BE Input to the transformation unit D1 to get N*ΔV BE , V BE and N*ΔV BE The difference Y between the two is obtained through the operation of adder D2, that is, Y=V BE -N*ΔV BE , comparator D3 quantizes Y, for example, compares Y with a preset reference voltage, and outputs V according to the comparison result. The value of V is 0 or 1. When the value of Y is greater than 0, V=1, otherwise V=0. The input of accumulator D4 is V, and the output is N. If the input V=1 of accumulator D4, the value of accumulator output N increases by 1 in each clock cycle. On the contrary, if V=0, stop accumulating N, the value of output N no longer changes, and N is saved or output. When the comparator flips, it means N*ΔV BE Closest to V BE , which is equivalent to Y=V BE -N*ΔV BE ≈0, that is, N≈V BE / ΔV BE According to formula (1) and formula (2), when high accuracy is not required, N can be regarded as quantitative temperature information.

[0047] Figure 2 In the embodiment shown, the comparator D3 compares the difference Y with the reference voltage. In some embodiments, the comparator D3 can also directly compare V BE and N*ΔV BE Comparison is made, that is, the two input terminals of comparator D3 are respectively input with V BE and N*ΔV BE , and outputs 0 or 1 according to the comparison result. In this embodiment, adder D2 is not required.

[0048] In another embodiment, VBE Is the value divided by the accumulated temperature information N close enough to ΔV? BE For example, V BE Input to the conversion unit D1 to get V BE / N,V BE / N and ΔV BE The difference Y between the two is obtained through the operation of adder D2, that is, Y=V BE / N-ΔV BE , comparator D3 quantizes Y, for example, compares Y with a preset reference voltage, and outputs V according to the comparison result. The value of V is 0 or 1. When the value of Y is greater than 0, V=1, otherwise V=0. The input of accumulator D4 is V, and the output is N. If the input V=1 of accumulator D4, the value of accumulator output N increases by 1 in each clock cycle. On the contrary, if V=0, the accumulation of N stops, the value of output N does not change, and N is saved or output.

[0049] As can be seen from the above, the implementation of the embodiment of the present invention is very simple, using only an adder (optional), a comparator and an accumulator, and both the hardware overhead and the power consumption are extremely low. The accuracy of the on-chip temperature given by the output N is sufficient to meet the needs of a large number of common applications (for example, adjusting analog circuit parameters (such as bias voltage and current) according to the on-chip temperature range, thereby reducing the temperature drift of the analog circuit).

[0050] Figure 2 The block diagram shown can be implemented in various ways, such as Figure 3 A specific embodiment is shown.

[0051] In such Figure 3 In the embodiment shown, the quantization circuit 20 includes an approximation difference unit 21, a comparator 22 and an accumulator (also called a counter) 23. The approximation difference unit 21 is used to at least implement the function of the conversion unit. The input end of the approximation difference unit 21 is connected to the output end of the front-end analog circuit 10 and is used to input the first electrical signal V BEL and the second electrical signal V BER , and based on the first electrical signal and the second electrical signal, obtain a positive temperature signal positively correlated with temperature and a negative temperature signal negatively correlated with temperature, then obtain a difference of N times the negative temperature signal and the positive temperature signal, and output a correlation value of the difference, which can be the difference itself or a first-order linear function of the difference, such as a constant multiple of the difference. That is, the approximate difference unit 21 is mainly used to obtain V in formula (1) according to N determined by the current clock cycle. BE -N*ΔV BEThe value of N is given by the accumulator 23. The input end of the comparator 22 is connected to the output end of the approximate difference unit 21, and the output end is connected to the accumulator 23, which is used to control the operation of the accumulator 23 according to the difference obtained by the approximate difference unit 21. When N*ΔV BE Not close enough to V BE When N*ΔV BE Close enough to V BE , the accumulator 23 stops the accumulation operation and outputs the N calculated at this time.

[0052] In a specific embodiment, the approximate difference unit is implemented by a switched capacitor circuit, including a first branch and a second branch, the first branch includes a first capacitor C1, which is used to obtain a negative temperature signal based on the first electrical signal, and use the negative temperature signal to charge the first capacitor C1, the second branch includes a second capacitor C2, which is used to obtain a positive temperature signal based on at least the second electrical signal, and use the positive temperature signal to charge the second capacitor C2, the capacitance value of the second capacitor C2 is controlled by the accumulated result N output by the accumulator, so that the capacitance value of the second capacitor is N times the capacitance value of the first capacitor, the output ends of the first branch and the second branch are connected, so that the charging charges of the first branch and the second branch simultaneously affect the voltage of the node A connected to the output ends of the two branches, and the voltage is transmitted to the comparator as the output voltage of the approximate difference unit.

[0053] In a specific embodiment, Figure 3 As shown, the first branch includes a second switch T2, a third switch T3 and a first capacitor C1, the second switch T2 and the third switch T3 are connected in parallel to a first end of the first capacitor, and the other ends of the second switch T2 and the third switch T3 are respectively connected to the first electrical signal V output by the analog front-end circuit 10 BEL and zero potential, the second branch includes a fourth switch T4, a fifth switch T5 and a second capacitor C2, the fourth switch T4 and the fifth switch T5 are connected in parallel to a first end of the second capacitor C2, and the other ends of the fourth switch T4 and the fifth switch T5 are respectively connected to the first electrical signal V output by the analog front-end circuit 10 BEL and the second electrical signal V BER , by connecting the first electrical signal V BEL and the second electrical signal V BER The difference ΔV BEInput to the first end of the second capacitor C2. The second capacitor C2 is a variable capacitor, and its capacitance control end is connected to the output end of the accumulator 23, for receiving the accumulation result N output by the accumulator 23, and controlling the capacitance value of the second capacitor C2 to be N times the capacitance value of the first capacitor C1 based on the accumulation result N. The second ends of the first capacitor C1 and the second capacitor C2 are connected to the A node, and the A node is grounded through the first switch T1 and connected to the input end of the comparator 22.

[0054] In a specific embodiment, the digital temperature sensor further includes a clock signal generating circuit (not shown in the figure) for generating the clock required by each part of the digital temperature sensor so that each part of the digital temperature sensor performs operations according to a constant periodic beat.

[0055] In this embodiment, the clock signal generating circuit generates at least three clock signals, namely, a first clock signal CL1, a second clock signal CL2, and a third clock signal CL3. The first switch T1 switches between an on-state and an off-state based on the control of the first clock signal CL1, the second switch T2 and the fourth switch T4 switch between an on-state and an off-state based on the control of the second clock signal CL2, and the third switch T3 and the fifth switch T5 switch between an on-state and an off-state based on the control of the third clock signal CL3. In a specific embodiment, in each clock cycle, there is a time overlap between the on-phase of the first clock signal CL1 and the on-phase of the second clock signal CL2, and there is no time overlap between the on-phase of the first clock signal CL1 and the on-phase of the third clock signal CL3, and there is no time overlap between the on-phase of the second clock signal CL2 and the on-phase of the third clock signal CL3, such as Figure 4 shown.

[0056] Preferably, in each clock cycle, the conduction phase of the second clock signal (for example, the high level period of one clock cycle) lags behind the end of the conduction phase of the first clock signal, and the start of the conduction phase of the third clock signal lags behind the end of the conduction phase of the second clock signal.

[0057] The comparator 22 includes a comparator A V , Comparator A V The two input terminals of comparator A are connected to node A and reference voltage source respectively. V The inverting input terminal of the comparator A is connected to the A node, and the non-inverting input terminal is connected to the reference voltage source, which are used to input the voltage of the A node and the reference voltage respectively. VThe voltage of the A node is compared with the reference voltage, and the first level or the second level is output according to the comparison result. The reference voltage can be set to zero potential or a fixed voltage according to the voltage of the A node, and according to the trigger logic of the accumulator 23, the first level can be a high level "1" and the second level can be a low level "0", or vice versa. According to the concept created by the present invention, when the approximate difference unit 21 continuously increases N according to formula (1), so that N*ΔV BE Approaching V BE When the loop operation is performed, it can be designed in V BE -N*ΔV BE >0, the comparator AV outputs a high level. BE -N*ΔV BE When it is equal to 0 or less than 0, the comparator AV outputs a low level.

[0058] In a more preferred embodiment, the comparator 22 may further include a circuit connected between the A node and the comparator A. V The third capacitor C between the input terminals AZ , used to eliminate comparator offset. It may further include a V The comparator 22 may further include a sixth switch T6 connected between the output terminal and the inverting input terminal of the comparator A, so that the comparator constitutes an automatic zeroing comparator. V A latch is provided between the output terminal of the comparator and the accumulator 23 so that the output of the comparator and the action of the accumulator 23 are synchronized.

[0059] The input end of the accumulator 23 is connected to the output end of the comparator 22, and the output end is connected to the approximate difference unit 21, and is used to perform the accumulation operation of N=N+1 according to the clock beat when the comparator 22 outputs the first level, and output the accumulation result N to the approximate difference unit, and stop accumulating when the comparator outputs the second level. The initial value of the accumulator 23 can be set to 0 or 1, and when the accumulation stops, N is output to the digital processing circuit.

[0060] In this embodiment, the approximation difference unit 21 inputs the first electrical signal V BEL and the second electrical signal V BER , output and V BE -N*ΔV BE The relevant voltage can be designed by the parameters of each component so that BE -N*ΔV BE >0, comparator A V Output high level, when V BE -N*ΔV BE When it is equal to 0 or less than 0, comparator A VOutput low level. In this case, when the accumulator 23 receives a high level, it performs an accumulation operation of N=N+1, and outputs the accumulation result N to the second capacitor C2, adjusting the capacitance of the second capacitor to double the capacitance of the first capacitor C1. When the capacitance of the second capacitor increases, it affects the voltage output by the approximate difference unit 21 through charging. When the voltage output by the approximate difference unit 21 changes to a certain extent, it affects the output level of the comparator 22, causing the output level of the comparator 22 to flip, and the accumulator 23 stops accumulating N, thereby finding a voltage that can make N*ΔV BE As close to V as possible BE The N value of .

[0061] The detailed workflow of this embodiment is as follows:

[0062] In the φ1 phase (i.e., the high level period of a clock cycle) of the first clock signal CL1 and the second clock signal CL2, T1, T2, and T4 are closed, point A is grounded, and V BEL Charge capacitors C1 and C2. Charges are stored on the plates of C1 and C2 near point A. The charge stored at point A during the φ2 phase (i.e., the low level period of a clock cycle) of the first clock signal CL1 and the second clock signal CL2 is consistent with the phase of φ1. The voltage at point A is N*ΔV BE -V BEL Then divide it by a fixed number. The specific mathematical derivation is as follows:

[0063] In the φ1 phase:

[0064] ……………………………… (3)

[0065] Among them, V A 、V B_φ1 、V C_φ1 are the voltages of nodes A, B, and C, respectively. OS is the output voltage of the voltage source, A V is the gain of the comparator.

[0066] The amount of charge stored on the plate near point A is Q A_φ1 for:

[0067] ……………… (4)

[0068] Among them, C S is the capacitance value of capacitor C1.

[0069] In the φ2 phase, the charge Q is stored on the plate near point A. A_φ2 for:

[0070] ……… (5)

[0071] According to the above formula, we can get:

[0072]

[0073] ………… (6)

[0074] Finally we get:

[0075] ………………………… (7)

[0076] When N*ΔV BE -V BEL When it is less than 0, the comparator output is a fixed level, and the accumulator continues to count. As the accumulator output N continues to increase, N*ΔV BE -V BEL At a certain moment, it will be equal to or greater than 0, at which time the output level of the comparator flips and the accumulator stops counting.

[0077] Because ΔV BE and V BEL All of them are temperature-related data, among which ΔV BE Positively correlated with temperature, V BEL Negatively correlated with temperature, so at different temperatures, N*ΔV BE -V BEL The N value for polarity flipping is different.

[0078] Under a certain process, the N value and the corresponding temperature also have a certain relationship, so N can be used to represent the temperature value measured by the temperature sensor.

[0079] When the accumulator stops counting, the value of N is determined, and the digital processing circuit 30 can read N from the accumulator 23 or the accumulator directly outputs N. Figure 5 The curve shown is a quantitative curve diagram of the quantitative target X, that is, the temperature value T on the horizontal axis corresponding to the vertical axis N can be found.

[0080] In the absence of C AZ In the embodiment of , there is also formula (6). Formula (6) indicates that the approximation difference unit outputs a fixed multiple of the difference between the negative temperature signal and the positive temperature signal N times. In some embodiments, the approximation difference unit may also output the difference between the negative temperature signal and the positive temperature signal N times.

[0081] In another embodiment, Figure 3The input signals of the first branch and the second branch in the circuit can also be interchanged, that is, the second branch inputs a negative temperature signal, and the first branch inputs a positive temperature signal. The capacitance value of the second capacitor C2 is controlled by the accumulated value N (temperature information) output by the accumulator 23, so that the capacitance value of the second capacitor C2 is 1 / N of the first capacitor C1, so that V is obtained at node A. BE / N-ΔV BE The difference or function of the difference.

[0082] According to the above analysis, this embodiment realizes the detection of temperature without using ADC. After actual measurement, it can meet the requirement that when the quantization accuracy of X is 1, the accuracy of the corresponding temperature information is within ±10 o C error range. And this embodiment has the following effects:

[0083] 1) Since the solution avoids using a high-precision ADC and instead uses an accumulator, the hardware overhead and area of ​​the chip can be reduced, and the power consumption of the chip can be reduced.

[0084] 2) Digital output of temperature can be achieved.

[0085] The above embodiment is to set V BEL Input to C1, if V BER Input to C1, because V BER Greater than V BEL , so the approximation to the difference unit is V BER -N*ΔV BE The difference, when V BER -N*ΔV BE When it is greater than 0, the comparator output is a fixed level, and the accumulator continues to count. As the accumulator output N continues to increase, V BER -N*ΔV BE At a certain moment, it will be equal to or less than 0, at which time the output level of the comparator is reversed and the accumulator stops counting.

[0086] Embodiment 2:

[0087] The difference between the second embodiment and the first embodiment lies in that the structure of the front-end analog circuit is different, and the two first electrical signals and the second electrical signals input by the approximate difference unit 21 are different.

[0088] In this embodiment, the structure of the front-end analog circuit is as follows: Figure 6As shown, the temperature sensing element adopts a thermistor, and the front-end analog circuit includes two current sources and two thermistors. The resistors R1 and R2 are resistors with different temperature coefficients, wherein the resistor R1 is a negative temperature coefficient thermistor that is negatively correlated with the temperature, and the resistor R2 is a positive temperature coefficient thermistor that is positively correlated with the temperature. The current source outputs I1, which is a current that does not change with temperature, and the voltage V1 of the resistor R1 and the voltage V2 of the resistor R2 are respectively a voltage with a negative temperature coefficient and a voltage with a positive temperature coefficient.

[0089] In this embodiment, the first electrical signal and the second electrical signal input to the approximate difference unit 21 are voltage V1 and voltage V2 respectively. Figure 7 As shown, the second switch T2 is connected to the voltage V1, the third switch T3 is connected to the 0 potential, the fourth switch T4 is connected to the voltage V2, and the fifth switch T5 is connected to the 0 potential.

[0090] In practical applications, the digital temperature sensor of the above embodiment can be designed as an independent chip or discrete device, and the clock signal generating circuit can be designed as a part of the digital temperature sensor on the chip or in the device. In another embodiment, the digital temperature sensor may not include the clock signal generating circuit, but obtain the clock signal through the clock signal generating circuit of the external system.

[0091] In some embodiments, the digital temperature sensor can also be integrated on chips with other functions, such as complex chips such as GPU, FPGA, CPU and accelerator. In the prior art, these chips with specific functions usually integrate a digital temperature sensor to detect the temperature of the chip. Since the digital temperature sensor in the embodiment of the present invention has a simple structure, low cost, small footprint and low power consumption, multiple digital temperature sensors can be integrated on a chip with specific functions (such as GPU, FPGA, CPU and accelerator chips). Figure 8 As shown, the chip includes a chip substrate 1 for realizing a preset operation or processing function and a plurality of digital temperature sensors in the above-mentioned embodiments distributed on the substrate 1. The number and distribution positions of the digital temperature sensors can be designed according to actual needs, for example, a 2*2 matrix or a 3*3 matrix can be formed. As the chip function and area increase, such multi-point distributed digital temperature sensors can detect the temperature within their respective sensing ranges, thereby realizing the detection of the local temperature of the chip and realizing the control of the local temperature.

[0092] The above specific examples are used to illustrate the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the art, according to the concept of the present invention, some simple deductions, modifications or substitutions can be made.

Claims

1. A digital temperature sensor, comprising a front-end analog circuit and a quantization circuit for reading quantized temperature information, characterized in that: The front-end analog circuit is used to sense temperature and output a first electrical signal and a second electrical signal containing temperature information; The quantization circuit is connected to the front-end analog circuit, and is used to input the first electrical signal and the second electrical signal output by the front-end analog circuit, and obtain a positive temperature signal positively correlated with the temperature and a negative temperature signal negatively correlated with the temperature based on the first electrical signal and the second electrical signal, and output quantized temperature information N based on the positive temperature signal and the negative temperature signal, wherein the value of the temperature information N is a positive integer when the product of the positive temperature signal and the negative temperature signal with a smaller absolute value of the temperature coefficient multiplied by the temperature information N is closest to the other, or the value of the temperature information N is a positive integer when the quotient of the positive temperature signal and the negative temperature signal with a larger absolute value of the temperature coefficient divided by the temperature information N is closest to the other; the quantization circuit includes: A transformation unit is used to multiply the one with the smaller absolute value of the temperature coefficient of the positive temperature signal and the negative temperature signal by the continuously accumulated temperature information N, and obtain a product that increases successively; or to divide the one with the larger absolute value of the temperature coefficient of the positive temperature signal and the negative temperature signal by the continuously accumulated temperature information N, and obtain a quotient that decreases successively; the transformation unit includes an approximate difference unit, the input end of the approximate difference unit is connected to the output end of the front-end analog circuit, and is used to input the first electrical signal and the second electrical signal, and obtain a positive temperature signal positively correlated with the temperature and a negative temperature signal negatively correlated with the temperature based on the first electrical signal and the second electrical signal. When the absolute value of the temperature coefficient of the negative temperature signal is greater than the absolute value of the temperature coefficient of the positive temperature signal, the approximate difference unit is also used to obtain the difference between the negative temperature signal and N times the positive temperature signal, or to obtain the quotient of the negative temperature signal divided by N and the difference between the positive temperature signal; when the temperature of the negative temperature signal When the absolute value of the temperature coefficient is less than the absolute value of the temperature coefficient of the positive temperature signal, the approximate difference unit is also used to obtain the difference of the positive temperature signal minus N times the negative temperature signal, or to obtain the difference of the quotient of the positive temperature signal divided by N minus the negative temperature signal; output the relevant value of the difference, the relevant value of the difference is the difference or the function value of the difference; the approximate difference unit includes a first branch and a second branch, the first branch includes a first capacitor, which is used to charge the first capacitor using one of the negative temperature signal and the positive temperature signal, the second branch includes a second capacitor, which is used to charge the second capacitor using the other of the positive temperature signal and the negative temperature signal, the second capacitor is a variable capacitor, and its capacitance value is controlled by the accumulated result N output by the accumulator, so that the capacitance value of the second capacitor is N times or 1 / N of the capacitance value of the first capacitor; the output end of the first branch and the output end of the second branch are connected to node A; A comparator, wherein an input terminal of the comparator is connected to the node A, and is used to output a first level when the successively increasing product or the successively decreasing quotient does not reach the closest to the other, and output a second level when it reaches the closest to the other; The accumulator is used to set the initial value of the temperature information N to 1, and accumulate N following the clock cycle based on the first level output by the comparator, and output the accumulated N to the transformation unit. The accumulator stops accumulating N when the comparator outputs the second level, and outputs N after stopping accumulation as the quantized temperature information.

2. The digital temperature sensor according to claim 1, characterized in that: The input terminal of the comparator is used to input the relevant value of the difference, and when the difference is greater than 0, a first level is output, otherwise a second level is output.

3. The digital temperature sensor according to claim 2, characterized in that: The approximate difference unit also includes a first switch connecting node A to ground, and the two input terminals of the comparator are respectively used to input the voltage of node A and the reference voltage. The comparator is used to compare the voltage of node A with the reference voltage, and output a first level when the voltage of node A is greater than the reference voltage, and output a second level when the voltage of node A is less than or equal to the reference voltage.

4. The digital temperature sensor according to claim 3, characterized in that: The first branch also includes a second switch and a third switch, wherein the first ends of the second switch and the third switch are respectively used to access the input signal, and the second ends are connected in parallel to the first end of the first capacitor, and one of the negative temperature signal and the positive temperature signal is input to the first end of the first capacitor in parallel, and the second end of the first capacitor is connected to the output end of the first branch, and the second branch includes a fourth switch and a fifth switch, wherein the first ends of the fourth switch and the fifth switch are respectively used to access the input signal, and the second ends are connected in parallel to the first end of the second capacitor, and the other of the negative temperature signal and the positive temperature signal is input to the first end of the second capacitor in parallel, and the second end of the second capacitor is connected to the output end of the second branch.

5. The digital temperature sensor according to claim 4, characterized in that: The first electrical signal and the second electrical signal output by the front-end analog circuit are both signals negatively correlated with temperature, and the difference between the first electrical signal and the second electrical signal is a signal positively correlated with temperature. The first end of the second switch is used to access one of the first electrical signal and the second electrical signal, and the first end of the third switch is grounded, so as to charge the first capacitor with one of the first electrical signal and the second electrical signal as a negative temperature signal; the first end of the fourth switch is used to access one of the first electrical signal and the second electrical signal, and the first end of the fifth switch is used to access the other of the first electrical signal and the second electrical signal, so as to charge the second capacitor with the difference between the first electrical signal and the second electrical signal as a positive temperature signal; or, The first electrical signal output by the front-end analog circuit is a signal negatively correlated with temperature, and the second electrical signal is a signal positively correlated with temperature. The first end of the second switch is used to access the first electrical signal, and the first end of the third switch is grounded, so that the first electrical signal is used as a negative temperature signal to charge the first capacitor; the first end of the fourth switch is used to access the second electrical signal, and the first end of the fifth switch is grounded, so that the second electrical signal is used as a positive temperature signal to charge the second capacitor.

6. The digital temperature sensor according to claim 4, characterized in that: The first switch switches between the on and off states based on the control of the first clock signal, the second switch and the fourth switch switch between the on and off states based on the control of the second clock signal, and the third switch and the fifth switch switch between the on and off states based on the control of the third clock signal, and in each clock cycle, there is a time overlap between the on-phase of the first clock signal and the on-phase of the second clock signal, the on-phase of the second clock signal lags behind the end of the on-phase of the first clock signal, and there is no time overlap between the on-phase of the first clock signal, the on-phase of the second clock signal and the on-phase of the third clock signal, and the start of the on-phase of the third clock signal lags behind the end of the on-phase of the second clock signal.

7. The digital temperature sensor according to claim 6, characterized in that: It also includes a clock signal generating circuit, which is used to generate a first clock signal, a second clock signal and a third clock signal.

8. The digital temperature sensor according to claim 1, characterized in that: The comparators include comparator A V and the third capacitor, Comparator A V The two input terminals are connected to the A node and the reference voltage source respectively, and the third capacitor is connected between the A node and the comparator A V Between the input terminals.

9. The digital temperature sensor according to claim 1, characterized in that: The device also includes a digital processing circuit, which is connected to the quantization circuit and is used to output a temperature value based on the quantized temperature information output by the quantization circuit.

10. A digital temperature sensor, comprising a front-end analog circuit and a quantization circuit for reading out quantized temperature information, characterized in that: The front-end analog circuit is used to sense temperature and output a first electrical signal and a second electrical signal containing temperature information; The quantization circuit comprises: A transformation unit, wherein the transformation unit includes an approximate difference unit, wherein an input end of the approximate difference unit is connected to an output end of a front-end analog circuit, and is used to input a first electrical signal and a second electrical signal, and obtain a positive temperature signal positively correlated with temperature and a negative temperature signal negatively correlated with temperature based on the first electrical signal and the second electrical signal; the approximate difference unit includes a first branch and a second branch, wherein the first branch includes a first capacitor, and is used to charge the first capacitor using one of a negative temperature signal and a positive temperature signal, and the second branch includes a second capacitor, and is used to charge the second capacitor using the other of a positive temperature signal and a negative temperature signal, wherein the second capacitor is a variable capacitor, and a capacitance value thereof is controlled by an accumulated result N output by an accumulator, so that the capacitance value of the second capacitor is N times or 1 / N of the capacitance value of the first capacitor; the output end of the first branch and the output end of the second branch are connected to a node A; A comparator, wherein two input terminals of the comparator are respectively used to input a voltage of a node A and a reference voltage, the comparator is used to compare the voltage of the node A with the reference voltage, and output a first level when the voltage of the node A is greater than the reference voltage, and output a second level when the voltage of the node A is less than or equal to the reference voltage; The accumulator is used to set the initial value of the temperature information N to 1, and accumulate N following the clock cycle based on the first level output by the comparator, and output the accumulated N to the transformation unit. The accumulator stops accumulating N when the comparator outputs the second level, and outputs N after stopping accumulation as the quantized temperature information.

11. A chip, comprising a chip substrate for implementing a preset operation or processing function, characterized in that: A plurality of digital temperature sensors according to any one of claims 1 to 10 are distributed on the chip substrate.

Images