Gain adjustment circuit of temperature sensor and temperature sensor

Abstract

The present application provides a gain adjustment circuit for a temperature sensor and a temperature sensor, wherein the gain adjustment circuit of the temperature sensor includes a positive correlation current adjustment module that generates a first charging current and a second charging current; a negative correlation current adjustment module that generates a first discharge current and a second discharge current; a capacitor module that integrates the first charging current and the first discharge current, or the second charging current and the second discharge current, to obtain an integrated voltage; a control module that outputs a discharge signal when the integrated voltage is greater than a preset reference voltage; conversely, outputs a charging signal; and determines a temperature gain coefficient based on the first charging current, the first discharge current, the second charging current, and the second discharge current. The present application determines the temperature gain coefficient by using the first charging current, the first discharge current, the second charging current, and the second discharge current, thereby increasing the range of variation of the temperature gain coefficient, enabling a more accurate representation of temperature and alleviating pressure on subsequent analog-to-digital conversion circuits.

Description

Technical Field

[0001] The present application belongs to the technical field of temperature sensors, and in particular relates to a gain adjustment circuit of a temperature sensor and a temperature sensor. Background Art

[0002] A temperature sensor is a sensor that can detect ambient temperature and convert it into a usable signal output. A temperature sensor generally consists of a front-end detection circuit and an analog-to-digital conversion circuit. The front-end detection circuit detects the ambient temperature and generates an analog temperature signal, while the analog-to-digital conversion circuit converts the analog temperature signal into a digital temperature signal output.

[0003] Front-end detection circuits typically use the ratio of a voltage that's positively correlated with temperature to a reference voltage that's independent of temperature as the temperature gain. This allows temperature detection to determine the current ambient temperature simply by calculating the temperature gain. However, the existing temperature gain has a narrow temperature variation range, placing increased pressure on the subsequent analog-to-digital conversion circuitry and requiring high precision. Summary of the Invention

[0004] The purpose of the present application is to provide a gain adjustment circuit for a temperature sensor and a temperature sensor, aiming to solve the problem that the temperature gain variation range in traditional temperature sensors is small.

[0005] To achieve the above objectives, in a first aspect, an embodiment of the present application provides a gain adjustment circuit for a temperature sensor, comprising a positive correlation current adjustment module, a negative correlation current adjustment module, a capacitor module, and a control module;

[0006] The positive correlation current regulation module includes n positive correlation current mirror units, each of which receives a current that is positively correlated with temperature; the positive correlation current regulation module is configured to conduct k1 positive correlation current mirror units according to a charging signal to generate a first charging current, and to conduct k3 positive correlation current mirror units according to a discharging signal to generate a second charging current; wherein n≥k1>k3;

[0007] The negatively correlated current regulation module includes m negatively correlated current mirror units, each of which receives a current that is negatively correlated with the temperature; the negatively correlated current regulation module is configured to conduct k2 negatively correlated current mirror units according to the charging signal to generate a first discharge current, and to conduct k4 negatively correlated current mirror units according to the discharge signal to generate a second discharge current; wherein m≥k4>k2, and k1-k3=k4-k2;

[0008] The capacitor module is configured to charge according to the first charging current and the first discharging current and obtain an integrated voltage; or discharge according to the second charging current and the second discharging current and obtain an integrated voltage;

[0009] The control module is configured to output the discharge signal when the integrated voltage is greater than a preset reference voltage; and output the charge signal when the integrated voltage is less than the preset reference voltage;

[0010] A temperature gain coefficient is determined based on the first charging current, the first discharging current, the second charging current, and the second discharging current; wherein the temperature gain coefficient is used to characterize the temperature of the temperature sensor.

[0011] In another possible implementation of the first aspect, determining the temperature gain coefficient based on the first charging current, the first discharging current, the second charging current, and the second discharging current includes:

[0012] According to the charging charge equal to the discharging charge in the same cycle, we can get:

[0013] k1I ptat T1+k3I ptat T2=k2I ctat T1+k4I ctat T2,

[0014] Among them, I ptat is the current of the positive correlation current mirror unit, I ctat is the current of the negatively correlated current mirror unit, T1 is the output time of the charging signal in one cycle, and T2 is the output time of the discharging signal in one cycle;

[0015] Substitution The calculation formula of the temperature gain coefficient μ′ is:

[0016]

[0017] In another possible implementation manner of the first aspect, the positive correlation current mirror unit includes a positive correlation current mirror and a first switch;

[0018] The positive correlation current mirror is electrically connected to the first switch and the control module, and is configured to generate a current that is positively correlated with the temperature when the first switch is turned on;

[0019] The first switch is electrically connected to the control module and is configured to be turned on according to the charging signal or the discharging signal;

[0020] The negative correlation current mirror unit includes a negative correlation current mirror and a second switch;

[0021] The negative correlation current mirror is electrically connected to the second switch and the control module, and is configured to generate a current that is negatively correlated with the temperature when the second switch is turned on;

[0022] The second switch is electrically connected to the control module and is configured to be turned on according to the charging signal or the discharging signal.

[0023] In another possible implementation of the first aspect, the capacitor module includes an integrating capacitor;

[0024] The integration capacitor is configured to be charged according to the first charging current and the second charging current, and to be discharged according to the first discharging current and the second discharging current.

[0025] In another possible implementation of the first aspect, the control module includes a comparator, a trigger, and a dynamic element matching unit;

[0026] The comparator is configured to output a continuous high-level signal when the integrated voltage is greater than a preset reference voltage, and to output a continuous low-level signal when the integrated voltage is less than the preset reference voltage;

[0027] The trigger is configured to convert the continuous high-level signal of the comparator into a discrete high-level signal, and to convert the continuous low-level signal of the comparator into a discrete low-level signal;

[0028] The dynamic element matching unit is configured to turn on k1 positively correlated current mirror units and k2 negatively correlated current mirror units according to the discrete low-level signal of the trigger, and to turn on k3 positively correlated current mirror units and k4 negatively correlated current mirror units according to the discrete high-level signal of the trigger.

[0029] In another possible implementation of the first aspect, the turned-on k1 positive correlation current mirror units, k2 negative correlation current mirror units, k3 positive correlation current mirror units, and k4 negative correlation current mirror units are randomly selected each time.

[0030] In another possible implementation of the first aspect, the positive correlation current mirror unit includes a first PMOS transistor, a second PMOS transistor, and a third PMOS transistor;

[0031] The source of the first PMOS transistor is connected to electricity, the drain of the first PMOS transistor is electrically connected to the source of the second PMOS transistor, the drain of the second PMOS transistor is electrically connected to the source of the third PMOS transistor, the drain of the third PMOS transistor is electrically connected to the capacitor module, the gate of the first PMOS transistor and the gate of the second PMOS transistor are both connected to a bias voltage of a current positively correlated with the temperature, and the gate of the third PMOS transistor is electrically connected to the control module.

[0032] In another possible implementation of the first aspect, the negatively correlated current mirror unit includes a first NMOS transistor, a second NMOS transistor, and a first resistor;

[0033] The drain of the first NMOS transistor is electrically connected to the capacitor module, the source of the first NMOS transistor is electrically connected to one end of the first resistor, the other end of the first resistor is electrically connected to the drain of the second NMOS transistor, the source of the second NMOS transistor is grounded, the gate of the first NMOS transistor is connected to a bias voltage of a current negatively correlated with the temperature, and the gate of the second NMOS transistor is electrically connected to the control module.

[0034] In another possible implementation of the first aspect, the control module further includes:

[0035] The chopping module is electrically connected to the capacitor module, the positive correlation current regulation module, the negative correlation current regulation module and the comparator, and is configured to filter out the offset voltage and noise of the input signal of the comparator.

[0036] In a second aspect, an embodiment of the present application provides a temperature sensor comprising the gain adjustment circuit.

[0037] The beneficial effect of the embodiments of the present application compared with the prior art is that the gain adjustment circuit of the above-mentioned temperature sensor determines the temperature gain coefficient through the first charging current, the first discharging current, the second charging current and the second discharging current, thereby increasing the variation range of the temperature gain coefficient, being able to express the temperature more accurately, and alleviating the pressure on the subsequent analog-to-digital conversion circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0039] Figure 1A schematic diagram of the structure of a gain adjustment circuit of a temperature sensor provided in an embodiment of the present application;

[0040] Figure 2 A circuit diagram of a gain adjustment circuit for a temperature sensor provided in an embodiment of the present application;

[0041] Figure 3 A circuit diagram of a positive correlation current adjustment module of a gain adjustment circuit of a temperature sensor provided in an embodiment of the present application;

[0042] Figure 4 A circuit diagram of a negatively correlated current adjustment module of a gain adjustment circuit of a temperature sensor provided in an embodiment of the present application;

[0043] Figure 5 A schematic diagram of the variation range of the temperature gain coefficient of the gain adjustment circuit of the temperature sensor provided in an embodiment of the present application;

[0044] Figure 6 This is a schematic diagram of control module signals of the gain adjustment circuit of the temperature sensor provided in an embodiment of the present application.

[0045] Description of reference numerals:

[0046] 1-positive correlation current regulation module, 2-negative correlation current regulation module, 3-capacitance module, 4-control module, 41-dynamic element matching unit, 42-chopping module. DETAILED DESCRIPTION

[0047] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0048] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0049] Traditional front-end detection circuits generally detect the negatively correlated voltage V of two bipolar transistors that are negatively correlated with temperature. BE1 With V BE2 , we get a positively correlated voltage ΔV which is positively correlated with temperature BE =V BE1 -V BE2 , the negative related voltage V BE1 Positively correlated voltage ΔV BEThe weights are added together to obtain a temperature-independent reference voltage V REF =V BE1 +α·ΔV BE , according to α·ΔV BE With the reference voltage V REF The ratio of the temperature gain μV BE1 =(1-μ)α·ΔV BE , according to the charge conservation principle, V BE1 T2=α·△V BE T1, where T1 is the voltage generation time that is positively correlated with temperature within a cycle, and T2 is the voltage generation time that is negatively correlated with temperature within a cycle, and substitute get Among them, μ can be regarded as a digital quantity positively correlated with temperature, and 1-μ can be regarded as a digital quantity negatively correlated with temperature.

[0050] Definition I c is a temperature-independent current, I c =V REF / R=(α△V BE +V BE1 ) / R, where V REF is a voltage that has nothing to do with temperature. Ignoring the temperature characteristics of the resistor R, I c It is a current that has nothing to do with temperature. The current I is positively correlated with temperature. ptat =α△V BE / R, current I which is negatively correlated with temperature ctat =V BE1 / R, temperature-independent current I c =V REF / R=(α△V BE +V BE1 ) / R, so the temperature-independent current Ic=I ptat +I ctat .

[0051] A linear transformation of the temperature gain μ is performed to fit a straight line: T = A·μ + B, where A and B are fixed constants, typically A ≈ 620 and B ≈ -280. In practical applications, knowing only the μ value is sufficient to determine the current temperature. This temperature measurement method has a narrow temperature gain variation range. For example, as the temperature changes from -40°C to 125°C, the μ value changes from approximately 0.4 to 0.6, a variation of only 20%. This increases the pressure on the subsequent analog-to-digital conversion circuitry and requires high precision.

[0052] The present application provides a gain adjustment circuit, in which a positively correlated current adjustment module obtains a first charging current and a second charging current that are positively correlated with temperature, and a negatively correlated current adjustment module obtains a first discharge current and a second discharge current that are negatively correlated with temperature. A control module determines a temperature gain coefficient based on the first charging current, the first discharge current, the second charging current, and the second discharge current, thereby increasing the range of variation of the temperature gain coefficient, being able to more accurately represent the temperature, and alleviating the pressure on the subsequent analog-to-digital conversion circuit.

[0053] The following is an illustrative description of the gain adjustment circuit of the temperature sensor provided in the present application in conjunction with the accompanying drawings.

[0054] Figure 1 This is a schematic diagram of the structure of the gain adjustment circuit of the temperature sensor provided in the embodiment of the present application. Figure 1 As shown, illustratively, a gain adjustment circuit 100 of a temperature sensor includes a positive correlation current adjustment module 1 , a negative correlation current adjustment module 2 , a capacitor module 3 and a control module 4 .

[0055] The positive correlation current regulation module 1 includes n positive correlation current mirror units, and the positive correlation current mirror units are connected to the current I that is positively correlated with the temperature. ptat ; The positive correlation current regulation module 1 is configured to turn on k1 positive correlation current mirror units according to the charging signal to generate a first charging current, and turn on k3 positive correlation current mirror units according to the discharging signal to generate a second charging current; wherein, n≥k1>k3.

[0056] Negatively correlated current regulation module 2 includes m negatively correlated current mirror units, and the negatively correlated current mirror units are connected to a current I that is negatively correlated with temperature. ctat ; The negatively correlated current regulation module 2 is configured to turn on k2 negatively correlated current mirror units according to the charging signal to generate a first discharge current, and to turn on k4 negatively correlated current mirror units according to the discharge signal to generate a second discharge current; wherein, m≥k4>k2.

[0057] In order to satisfy the charge conservation in the charging and discharging processes of the gain adjustment circuit of the temperature sensor provided in the embodiment of the present application, k1-k3=k4-k2.

[0058] The capacitor module 3 is configured to charge according to the first charging current and the first discharging current and obtain an integrated voltage; or to discharge according to the second charging current and the second discharging current and obtain an integrated voltage.

[0059] The control module 4 is configured to output a discharge signal when the integrated voltage is greater than a preset reference voltage; and output a charge signal when the integrated voltage is less than the preset reference voltage.

[0060] A temperature gain coefficient is determined based on the first charging current, the first discharging current, the second charging current, and the second discharging current; wherein the temperature gain coefficient is used to characterize the temperature of the temperature sensor.

[0061] In the embodiment of the application, first, the control module generates an initial charging signal, and the positive correlation current regulation module selects and turns on k1 positive correlation current mirror units according to the charging signal to generate a first charging current k1I ptat The negatively correlated current regulation module selects and turns on k2 negatively correlated current mirror units according to the charging signal to generate the first discharge current k2I ctat , get the total charging current k1I ptat -k2I ctat , charging the integral capacitor to obtain the charging integral voltage (Vx1); the control module determines the voltage value of the charging integral voltage in real time, and as the voltage value of the charging integral voltage rises, when the voltage value of the charging integral voltage is greater than the preset reference voltage (V REF1 ), the control module outputs a discharge signal.

[0062] The positive correlation current regulation module selects and turns on k3 positive correlation current mirror units according to the discharge signal to generate the second charging current k3I ptat The negatively correlated current regulating module selects and turns on k4 negatively correlated current mirror units according to the discharge signal to generate the second discharge current k2I ctat , get the total discharge current k3I ptat -k4I ctat , discharge the integral capacitor to obtain the discharge integral voltage (Vx2); the control module determines the voltage value of the discharge integral voltage in real time, and as the voltage value of the discharge integral voltage decreases, when the voltage value of the discharge integral voltage is less than the preset reference voltage (V REF1 ), the control module outputs a charging signal. It should be noted that the preset reference voltage V REF1 The reference voltage V in the traditional front-end detection circuit is independent of temperature. REF =V BE1 +α·ΔV BE Produced and obtained.

[0063] Then, the temperature gain coefficient is determined based on the first charging current, the first discharging current, the second charging current, and the second discharging current. Compared with the traditional front-end detection circuit which only determines the temperature gain by a positively correlated voltage that is positively correlated with temperature and a reference voltage that is independent of temperature, there are more determining factors, so that the temperature gain coefficient can have a larger range of variation, effectively alleviating the pressure on the subsequent analog-to-digital conversion circuit.

[0064] Exemplarily, determining the temperature gain coefficient based on the first charging current, the first discharging current, the second charging current, and the second discharging current includes:

[0065] According to the charging charge equal to the discharging charge in the same cycle, we can get:

[0066] k1I ptat T1+k3I ptat T2=k2I ctat T1+k4I ctat T2 (1)

[0067] Among them, I ptat is the current of the positive correlation current mirror unit, I ctat is the current of the negatively correlated current mirror unit, T1 is the charging signal output time in one cycle, and T2 is the discharging signal output time in one cycle.

[0068] The calculation formula of temperature gain coefficient μ′ is:

[0069]

[0070] In the embodiment of the application, dividing both sides of formula (1) by T1+T2, we can get

[0071]

[0072] because Substituting into formula (3), we can get

[0073] (k1I ptat -k2I ctat )(1-μ′)=(k4I ctat -k3I ptat )μ′ (4)

[0074] According to formula (4), we can get:

[0075] (k1I ptat -k2I ctat )=((k4-k2)I ctat +(k1-k3)I ptat )μ′ (5)

[0076] Assume k1-k3=k4-k2, and the traditional front-end detection circuit has I ctat +I ptat =I c , put it into formula (5) and we can get,

[0077] k1I ptat -k2(I c -I ptat )=(k1-k3)I c μ′ (6)

[0078] According to formula (6), we can get:

[0079] (k1+k2)I ptat -k2I c =(k1-k3)I c μ′ (7)

[0080] In traditional front-end detection circuit Substituting into formula (7), we can get:

[0081]

[0082] in,

[0083] Therefore, by selecting appropriate k1, k2, k3, and k4, the variation range of the temperature gain coefficient in this application can be adjusted.

[0084] Figure 2 This is a circuit diagram of a gain adjustment circuit for a temperature sensor provided in an embodiment of the present application. Figure 2 As shown, exemplarily, the positive correlation current mirror unit includes a positive correlation current mirror and a first switch; the positive correlation current mirror is electrically connected to the first switch and the control module, and is configured to generate a current I that is positively correlated with the temperature when the first switch is turned on. ptat ; The first switch is electrically connected to the control module and is configured to be turned on according to the charging signal or the discharging signal.

[0085] The negative correlation current mirror unit includes a negative correlation current mirror and a second switch; the negative correlation current mirror is electrically connected to the second switch and the control module, and is configured to generate a current I that is negatively correlated with the temperature when the second switch is turned on. ctat ; The second switch is electrically connected to the control module and is configured to be turned on according to the charging signal or the discharging signal.

[0086] In an embodiment of the present application, the positive correlation current regulation module may include n positive correlation current mirror units, which may correspondingly include n positive correlation current mirrors and n first switches. Based on a charging signal from the control module, k1 first switches may be closed, thereby causing the k1 positive correlation current mirrors to jointly generate a first charging current. Alternatively, based on a discharge signal from the control module, k3 first switches may be closed, thereby causing the k3 positive correlation current mirrors to jointly generate a second charging current.

[0087] The negatively correlated current regulation module may include m negatively correlated current mirror units, which may correspondingly include m negatively correlated current mirrors and m second switches. Based on a charge signal from the control module, k2 second switches may be closed, thereby causing the k2 negatively correlated current mirrors to jointly generate a first discharge current. Alternatively, based on a discharge signal from the control module, k4 second switches may be closed, thereby causing the k4 negatively correlated current mirrors to jointly generate a second discharge current.

[0088] like Figure 2 As shown, exemplarily, the capacitor module 3 includes an integral capacitor C1; the integral capacitor C1 is configured to be charged according to a first charging current and a second charging current, and to be discharged according to a first discharging current and a second discharging current.

[0089] In the embodiment of the present application, the lower plate of the integrating capacitor C1 is grounded, and the upper plate (i.e., the Vx terminal) of the integrating capacitor C1 is connected to the positive-correlation current regulating module, the negative-correlation current regulating module, and the control module (i.e., the positive input terminal of the first comparator). During the charging process, the total charging current generated by the positive-correlation current regulating module and the negative-correlation current regulating module charges the integrating capacitor C1. During the discharging process, the total discharge current generated by the positive-correlation current regulating module and the negative-correlation current regulating module causes the integrating capacitor C1 to discharge, thereby changing the voltage value of the input terminal of the control module.

[0090] like Figure 2 As shown, exemplarily, the control module 4 includes a comparator U1 , a trigger U2 and a dynamic element matching unit 41 .

[0091] The comparator U1 is configured to output a continuous high-level signal when the integrated voltage is greater than a preset reference voltage, and to output a continuous low-level signal when the integrated voltage is less than the preset reference voltage.

[0092] The trigger U2 is configured to convert the continuous high-level signal of the comparator into a discrete high-level signal, and to convert the continuous low-level signal of the comparator into a discrete low-level signal.

[0093] The dynamic element matching unit 41 is configured to turn on k1 positively correlated current mirror units and k2 negatively correlated current mirror units according to a discrete low-level signal of the trigger, and to turn on k3 positively correlated current mirror units and k4 negatively correlated current mirror units according to a discrete high-level signal of the trigger.

[0094] In the embodiment of the present application, the preset reference voltage V REF1 The reference voltage V in the traditional front-end detection circuit is independent of temperature. REF =V BE1 +α·ΔV BE Comparator U1 compares the integrated voltage at its positive input with the reference voltage at its negative input. When the integrated voltage is greater than the reference voltage, the output is 1. When the integrated voltage is less than the reference voltage, the output is 0. The reference voltage is typically half the power supply voltage and can be generated using another simple reference circuit.

[0095] The trigger U2 can be a D trigger, which is used to sample the output result V of the comparator U1. O, converting continuous signals into discrete signals to facilitate subsequent digital system processing. For example, the continuous high-level signal of the comparator U1 is converted into a discrete high-level signal, and the continuous low-level signal of the comparator U1 is converted into a discrete low-level signal. The D pin (i.e., data input pin) of the D flip-flop is connected to the output pin of the comparator U1, and the clk pin of the D flip-flop is connected to the clock signal, which is directly provided by the system. The frequency of the clock signal is the sampling frequency of the D flip-flop, and the Q pin (i.e., output pin) of the D flip-flop is connected to the dynamic element matching unit 41. The D flip-flop adopts rising edge triggering, that is, only when the rising edge of the clock signal clk comes, the current input signal is sampled and latched and output, and the output value remains unchanged at other times. In addition, a second capacitor C2 can also be connected to the D pin of the trigger U2 to filter out noise in the output signal of the comparator U1.

[0096] The dynamic element matching unit (DEM) 41 generates a dynamic element matching signal according to the output signal D of the trigger U2. out Generate corresponding control signals to control the selection and conduction of corresponding number of positive related current regulation modules and negative related current regulation modules. out = 0, the charging signal is output, k1 positive related current mirror units are selected to be turned on, and k2 negative related current mirror units are selected to be turned on; when D out =1, a discharge signal is output, k3 positively correlated current mirror units are selected and turned on, and k4 negatively correlated current mirror units are selected and turned on.

[0097] Exemplarily, the turned-on k1 positively correlated current mirror units, k2 negatively correlated current mirror units, k3 positively correlated current mirror units, and k4 negatively correlated current mirror units are randomly selected each time.

[0098] In an embodiment of the present application, among n positively correlated current mirror units, k1 positively correlated current mirror units or k3 positively correlated current mirror units can be randomly selected; among m negatively correlated current mirror units, k2 negatively correlated current mirror units or k4 negatively correlated current mirror units can be randomly selected, thereby reducing the error caused by current mirror mismatch or process deviation. For example, when it is necessary to select and turn on k1 positively correlated current mirror units, the k1 positively correlated current mirror units are randomly selected, and are not fixed k1 positively correlated current mirror units. The k1 positively correlated current mirror units selected each time may be different. For example, when it is necessary to select and turn on 2 positively correlated current mirror units from 3 positively correlated current mirror units, there can be three combinations of 1 and 2, 1 and 3, and 2 and 3, thereby reducing the error caused by current mirror mismatch. Because the current generated by each current mirror unit is not completely equal, the error can be randomized by randomly selecting a fixed number of current mirror units.

[0099] Figure 3 This is a circuit diagram of a positive correlation current adjustment module of a gain adjustment circuit of a temperature sensor provided in an embodiment of the present application. Figure 3 As shown, exemplarily, the positive correlation current mirror unit includes a first PMOS transistor P1, a second PMOS transistor P2 and a third PMOS transistor P3.

[0100] The source of the first PMOS transistor P1 is connected to electricity, the drain of the first PMOS transistor P1 is electrically connected to the source of the second PMOS transistor P2, the drain of the second PMOS transistor P2 is electrically connected to the source of the third PMOS transistor P3, the drain of the third PMOS transistor P3 is electrically connected to the capacitor module 3, the gate of the first PMOS transistor P1 and the gate of the second PMOS transistor P2 are both connected to a bias voltage of a current positively correlated with temperature, and the gate of the third PMOS transistor P3 is electrically connected to the control module 4.

[0101] In the embodiment of the present application, the current positively correlated with temperature is the current generated by the current mirror composed of two transistors:

[0102] Among them, V C is the voltage at the emitter of the first transistor, V A The emitter of the second transistor is connected in series with the adjustment resistor R trim By selecting the appropriate size, the current obtained by the positive correlation current mirror unit can be α times the current positively correlated with the temperature, so the current flowing through the positive correlation current mirror unit can be In the embodiment of the present application, the n positively correlated current mirror units have the same size and the currents flowing through them are Thus, the control signal S output by the control module p1 、S p2 ,…S pn The k1 or k3 positive correlation current mirror units among the n positive correlation current mirror units are respectively controlled to be selected and output the positive correlation total current T ptat_total .

[0103] Figure 4 This is a circuit diagram of a negative correlation current adjustment module of a gain adjustment circuit of a temperature sensor provided in an embodiment of the present application. Figure 4 As shown, exemplarily, the negative correlation current mirror unit includes a first NMOS transistor N1, a second NMOS transistor N2 and a first resistor R1.

[0104] The drain of the first NMOS transistor N1 is electrically connected to the capacitor module 3, the source of the first NMOS transistor N1 is electrically connected to one end of the first resistor R1, the other end of the first resistor R1 is electrically connected to the drain of the second NMOS transistor N2, the source of the second NMOS transistor N2 is grounded, the gate of the first NMOS transistor N1 is connected to a bias voltage of a current negatively correlated with temperature, and the gate of the second NMOS transistor N2 is electrically connected to the control module 4.

[0105] In the embodiment of the present application, the current negatively correlated with the temperature can be generated by the first transistor, that is, The m negatively correlated current mirror units have the same size, and the currents flowing through them are Thus, the control signal S output by the control module n1 、S n2 ,…S nn Control k2 or k4 negative correlation current mirror units among n negative correlation current mirror units to be selected and output the negative correlation total current T ctat_total .

[0106] like Figure 2 As shown, illustratively, the control module 4 further includes:

[0107] The chopping module 42 is electrically connected to the capacitor module 3 , the positive correlation current regulating module 1 , the negative correlation current regulating module 2 and the comparator U1 , and is configured to filter out the offset voltage and noise of the input signal of the comparator.

[0108] In the embodiments of the present application, since the offset voltage and noise of the comparator can cause errors in the temperature detection of the temperature sensor, a chopping module can be used to reduce the offset voltage and noise of the comparator. A specific implementation method is to use frequency domain modulation and demodulation to modulate the offset voltage and signal of the comparator to different frequencies, and then filter out the offset voltage and signal modulated to high frequencies through a filter, thereby significantly reducing the offset voltage and noise of the comparator within the bandwidth.

[0109] Figure 5 This is a schematic diagram of the variation range of the temperature gain coefficient of the gain adjustment circuit of the temperature sensor provided in the embodiment of the present application. Figure 5 As shown, the temperature gain of the traditional front-end detection circuit is The variation range is 20%. The temperature gain coefficient of this application is The variation range is 60%, so the gain adjustment circuit of the temperature sensor of the present application effectively relieves the pressure of the subsequent analog-to-digital converter.

[0110] Figure 6 This is a schematic diagram of control module signals of the gain adjustment circuit of the temperature sensor provided in the embodiment of the present application. Figure 6As shown, the gain adjustment circuit of the temperature sensor of the present application works at a certain temperature. When the output pin D of the trigger U2 out = 0, k1 positive correlation current mirror units I ptat k2 negatively correlated current mirror units I ctat is selected, the total current (k1I ptat -k2I ctat ) charges the integral capacitor C1, and the positive input terminal V X The voltage at the positive input terminal V X The voltage value at the point is greater than the reference voltage V REF1 When the result of comparator U1 flips, the output pin D of trigger U2 out =1.

[0111] When the output pin D of the trigger U2 out =1, k3 positively correlated current mirror units I ptat is selected, k4 negatively correlated current mirror units I ctat is selected, the integrating capacitor C1 passes the total current (k3I ptat -k4I ctat ) to discharge, the positive input terminal V X The voltage at the point drops, when the positive input terminal V X The voltage value at the point is less than V REF1 When the result of comparator U1 is reversed again, the output pin D of trigger U2 out =0, and the process is continuously repeated, thereby maintaining the gain adjustment circuit of the present application in a stable adjustment state.

[0112] Illustratively, an embodiment of the present application provides a temperature sensor, including a gain adjustment circuit of the temperature sensor.

[0113] In an embodiment of the present application, the positive correlation current regulation module obtains the first charging current and the second charging current that are positively correlated with the temperature, and the negative correlation current regulation module obtains the first discharge current and the second discharge current that are negatively correlated with the temperature. The control module determines the temperature gain coefficient based on the first charging current, the first discharge current, the second charging current and the second discharge current, thereby increasing the variation range of the temperature gain coefficient, being able to more accurately express the temperature and alleviating the pressure on the subsequent analog-to-digital conversion circuit.

[0114] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0115] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned embodiment, which will not be repeated here.

[0116] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0117] Those skilled in the art will appreciate that the units of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0118] In the embodiments provided herein, it should be understood that the disclosed gain adjustment circuit for the temperature sensor can be implemented in other ways. For example, the embodiment of the gain adjustment circuit for the temperature sensor described above is merely illustrative. For example, the division of modules or units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some multi-interface system, device or unit, which can be electrical, mechanical or other forms.

[0119] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0120] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0121] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A gain adjustment circuit for a temperature sensor, characterized in that: It includes a positive correlation current regulation module, a negative correlation current regulation module, a capacitor module and a control module; The positive correlation current regulation module includes n positive correlation current mirror units, each of which receives a current that is positively correlated with temperature; the positive correlation current regulation module is configured to conduct k1 positive correlation current mirror units according to a charging signal to generate a first charging current, and to conduct k3 positive correlation current mirror units according to a discharging signal to generate a second charging current; wherein n≥k1>k3; The negatively correlated current regulation module includes m negatively correlated current mirror units, each of which receives a current that is negatively correlated with the temperature; the negatively correlated current regulation module is configured to conduct k2 negatively correlated current mirror units according to the charging signal to generate a first discharge current, and to conduct k4 negatively correlated current mirror units according to the discharge signal to generate a second discharge current; wherein m≥k4>k2, and k1-k3=k4-k2; The capacitor module is configured to charge according to the first charging current and the first discharging current and obtain an integrated voltage; or discharge according to the second charging current and the second discharging current and obtain an integrated voltage; The control module is configured to output the discharge signal when the integrated voltage is greater than a preset reference voltage; and output the charge signal when the integrated voltage is less than the preset reference voltage; and determining a temperature gain coefficient based on the first charging current, the first discharging current, the second charging current, and the second discharging current; wherein the temperature gain coefficient is used to characterize the temperature of the temperature sensor; The capacitor module includes an integral capacitor; The integrating capacitor is configured to be charged according to the first charging current and the second charging current, and to be discharged according to the first discharging current and the second discharging current; The turned-on k1 positive correlation current mirror units, k2 negative correlation current mirror units, k3 positive correlation current mirror units and k4 negative correlation current mirror units are randomly selected each time.

2. The gain adjustment circuit of the temperature sensor according to claim 1, wherein: The determining of the temperature gain coefficient based on the first charging current, the first discharging current, the second charging current, and the second discharging current includes: According to the charging charge equal to the discharging charge in the same cycle, we can get: k1I ptat T1+k3I ptat T2=k2I ctat T1+k4I ctat T2, Among them, I ptat is the current of the positive correlation current mirror unit, I ctat is the current of the negatively correlated current mirror unit, T1 is the output time of the charging signal in one cycle, and T2 is the output time of the discharging signal in one cycle; Substitution The calculation formula of the temperature gain coefficient μ′ is:

3. The gain adjustment circuit of the temperature sensor according to claim 1 or 2, characterized in that: The positive correlation current mirror unit includes a positive correlation current mirror and a first switch; The positive correlation current mirror is electrically connected to the first switch and the control module, and is configured to generate a current that is positively correlated with the temperature when the first switch is turned on; The first switch is electrically connected to the control module and is configured to be turned on according to the charging signal or the discharging signal; The negative correlation current mirror unit includes a negative correlation current mirror and a second switch; The negative correlation current mirror is electrically connected to the second switch and the control module, and is configured to generate a current that is negatively correlated with the temperature when the second switch is turned on; The second switch is electrically connected to the control module and is configured to be turned on according to the charging signal or the discharging signal.

4. The gain adjustment circuit of the temperature sensor according to claim 1 or 2, characterized in that: The control module includes a comparator, a trigger and a dynamic element matching unit; The comparator is configured to output a continuous high-level signal when the integrated voltage is greater than a preset reference voltage, and to output a continuous low-level signal when the integrated voltage is less than the preset reference voltage; The trigger is configured to convert the continuous high-level signal of the comparator into a discrete high-level signal, and to convert the continuous low-level signal of the comparator into a discrete low-level signal; The dynamic element matching unit is configured to turn on k1 positively correlated current mirror units and k2 negatively correlated current mirror units according to the discrete low-level signal of the trigger, and to turn on k3 positively correlated current mirror units and k4 negatively correlated current mirror units according to the discrete high-level signal of the trigger.

5. The gain adjustment circuit of the temperature sensor according to claim 1 or 2, characterized in that: The positive correlation current mirror unit includes a first PMOS tube, a second PMOS tube and a third PMOS tube; The source of the first PMOS transistor is connected to electricity, the drain of the first PMOS transistor is electrically connected to the source of the second PMOS transistor, the drain of the second PMOS transistor is electrically connected to the source of the third PMOS transistor, the drain of the third PMOS transistor is electrically connected to the capacitor module, the gate of the first PMOS transistor and the gate of the second PMOS transistor are both connected to a bias voltage of a current positively correlated with the temperature, and the gate of the third PMOS transistor is electrically connected to the control module.

6. The gain adjustment circuit of the temperature sensor according to claim 1 or 2, characterized in that: The negative correlation current mirror unit includes a first NMOS transistor, a second NMOS transistor and a first resistor; The drain of the first NMOS transistor is electrically connected to the capacitor module, the source of the first NMOS transistor is electrically connected to one end of the first resistor, the other end of the first resistor is electrically connected to the drain of the second NMOS transistor, the source of the second NMOS transistor is grounded, the gate of the first NMOS transistor is connected to a bias voltage of a current negatively correlated with the temperature, and the gate of the second NMOS transistor is electrically connected to the control module.

7. The gain adjustment circuit of the temperature sensor according to claim 4, wherein: The control module further includes: The chopping module is electrically connected to the capacitor module, the positive correlation current regulation module, the negative correlation current regulation module and the comparator, and is configured to filter out the offset voltage and noise of the input signal of the comparator.

8. A temperature sensor, characterized in that: A gain adjustment circuit comprising the temperature sensor according to any one of claims 1 to 7.

Images