Temperature sensor circuit and temperature sensor including the temperature sensor circuit

Abstract

This application discloses a temperature sensor circuit and a temperature sensor including the temperature sensor circuit. Temperature detection is performed by using the temperature coefficient of V be . Since its change with temperature is large, high-sensitivity temperature detection can be achieved. Moreover, in this application, the slope is fixed and not affected by the offset. Therefore, it only needs to be calibrated once at room temperature, and there is no need to measure the temperature curve at multiple temperature points, which greatly saves costs and improves accuracy. Embodiments of this application can achieve a larger slope with a smaller magnification factor to improve the sensitivity of the temperature sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor integrated circuits, and in particular to a temperature sensor circuit and a temperature sensor comprising the temperature sensor circuit. Background Art

[0002] At present, temperature sensors are widely used in semiconductor integrated circuits. They can be used to detect the on-chip temperature of instruments and equipment, as well as temperature changes such as ambient temperature. Therefore, it is very necessary to realize high-precision on-chip integrated temperature sensors. However, since the characteristics of CMOS (Complementary Metal Oxide Semiconductor) change with temperature, it is difficult to maintain the consistency of the circuit working state in IC (integrated circuit) design within the operable temperature range. This requires a voltage or current that only changes linearly with temperature to reflect temperature changes. Summary of the invention

[0003] The object of the present invention is to provide a temperature sensor circuit and a temperature sensor comprising the temperature sensor circuit, so as to improve the sensitivity of the temperature sensor.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A temperature sensor circuit includes: transistors M1-M5, resistors R1-R3, a first operational amplifier OP1, a second operational amplifier OP2 and a triode Q1, wherein:

[0006] The first end of the transistor M1, the first end of the transistor M2 and the first end of the transistor M3 are connected to VDD respectively, the second end of the transistor M1, the second end of the transistor M2 and the second end of the transistor M3 are connected, the first end of the transistor M1 is connected to the second end of the transistor M1, the common end thereof is connected to the first end of the transistor M4, the second end of the transistor M4 is connected to the output end of the first operational amplifier OP1, the third end of the transistor M4 is connected to the negative input end of the first operational amplifier OP1, and the common end thereof is grounded through a resistor R1, and the positive input end of the first operational amplifier OP1 is connected to the input power supply V1;

[0007] The third end of the transistor M2 is connected to the first end of the transistor M5, and the common end thereof is grounded through the resistor R2, and the common end thereof serves as the output end of the temperature sensor circuit; the second end of the transistor M5 is connected to the output end of the second operational amplifier OP2, the third end of the transistor M5 is grounded through the resistor R3, the third end of the transistor M5 is connected to the negative input end of the second operational amplifier OP2, the positive input end of the second operational amplifier OP2 is connected to the first end of the triode Q1, the first end of the triode Q1 is connected to the third end of the transistor M3, the second end of the triode Q1 is connected to the third end of the triode Q1, and the common end thereof is grounded;

[0008] The absolute value of the output voltage V0 at the output end of the temperature sensor circuit changing with temperature is the change of Vbe changing with temperature multiplied by the ratio of the resistance R2 / resistance R3.

[0009] Wherein, the transistors M1-M5 are field effect transistors.

[0010] The first end of the transistor M1 - M3 is a source, the second end of the transistor M1 - M3 is a gate, and the third end of the transistor M1 - M3 is a drain.

[0011] The first end of the transistor M4 - M5 is a drain, the second end of the transistor M4 - M5 is a gate, and the third end of the transistor M4 - M5 is a source.

[0012] Wherein, the transistor Q1 is a PNP transistor.

[0013] The first end of the switch tube Q1 is an emitter, the second end of the switch tube Q1 is a base, and the third end of the switch tube Q1 is a collector.

[0014] A temperature sensor comprises the temperature sensor circuit described above.

[0015] It can be seen from the above technical solution that, compared with the prior art, the temperature sensor circuit and the temperature sensor including the temperature sensor circuit provided by the present application use V be The temperature coefficient is used for temperature detection. Since it has a large change in temperature, high-sensitivity temperature detection can be achieved. In this application, the slope is fixed and is not affected by the offset, so it only needs to be calibrated once at room temperature, and there is no need to measure the temperature curve at multiple temperature points, which greatly saves costs and improves accuracy. This application can achieve a larger slope with a smaller magnification to improve the sensitivity of the temperature sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0017] Figure 1 A circuit diagram of a temperature sensor circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] The applicant found in the research that in the prior art, ΔV be The temperature coefficient is used to ensure the sensitivity of the temperature sensor, where and but So, use V be A larger slope can be achieved, in other words, a better sensitivity can be achieved by a large slope. However, the temperature slope in the prior art solution is low, so a sufficiently large amplification factor is required to achieve V be The coefficient of variation with temperature is about 17 times.

[0019] To this end, the present application provides a temperature sensor circuit and a temperature sensor including the temperature sensor circuit, the purpose of which is to achieve a larger slope through a smaller amplification factor to improve the sensitivity of the temperature sensor.

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] See also Figure 1 As shown, the temperature sensor circuit provided in the embodiment of the present application includes: transistors M1-M5, resistors R1-R3, a first operational amplifier OP1, a second operational amplifier OP2 and a triode Q1, wherein:

[0022] The first end of the transistor M1, the first end of the transistor M2 and the first end of the transistor M3 are respectively connected to VDD, the second end of the transistor M1, the second end of the transistor M2 and the second end of the transistor M3 are connected, the first end of the transistor M1 is connected to the second end of the transistor M1, the common end thereof is connected to the first end of the transistor M4, the second end of the transistor M4 is connected to the output end of the first operational amplifier OP1, the third end of the transistor M4 is connected to the negative input end of the first operational amplifier OP1, and the common end thereof is grounded through the resistor R1, and the positive input end of the first operational amplifier OP1 is connected to the voltage input end V1.

[0023] The third end of the transistor M2 is connected to the first end of the transistor M5, and the common end thereof is grounded through the resistor R2, and the common end thereof serves as the voltage output end Vo of the temperature sensor circuit; the second end of the transistor M5 is connected to the output end of the second operational amplifier OP2, and the third end of the transistor M5 is grounded through the resistor R3, the third end of the transistor M5 is connected to the negative input end of the second operational amplifier OP2, the positive input end of the second operational amplifier OP2 is connected to the first end of the transistor Q1, the first end of the transistor Q1 is connected to the third end of the transistor M3, the second end of the transistor Q1 is connected to the third end of the transistor Q1, and the common end thereof is grounded.

[0024] The absolute value of the output voltage V0 at the output end of the temperature sensor circuit changing with temperature is the change of Vbe changing with temperature multiplied by the ratio of the resistance R2 / resistance R3.

[0025] Furthermore, in the embodiment of the present application, the transistors M1-M5 are field effect transistors, wherein the first end of the transistors M1-M3 is a source, the second end of the transistors M1-M3 is a gate, and the third end of the transistors M1-M3 is a drain; the first end of the transistors M4-M5 is a drain, the second end of the transistors M4-M5 is a gate, and the third end of the transistors M4-M5 is a source.

[0026] Furthermore, in the embodiment of the present application, the transistor Q1 is a PNP transistor, wherein the first end of the transistor Q1 is an emitter, the second end of the transistor Q1 is a base, and the third end of the transistor Q1 is a collector.

[0027] Based on the temperature sensor disclosed above, the embodiment of the present application further discloses a temperature sensor, which includes the temperature sensor circuit described above.

[0028] Further, according to Figure 1To illustrate the working principle of the temperature sensor circuit provided in the embodiment of the present application:

[0029] like Figure 1 In the figure, I1 is the current generated by the input voltage V1 through the first operational amplifier OP1 and the transistor M4 on the resistor R1, where V1 is the zero-temperature voltage VBG generated by BG, that is, I2 is generated by I1 through a current mirror formed by transistors M1 and M2, that is, I2 = K′I1, where K is the ratio of transistors M2 to M1, and K′ is the parameter of K after mismatch is considered; I3 is the current generated by the Vbe of the switch tube Q1 through the second operational amplifier OP2 and the transistor M5 on the resistor R3, that is, Therefore, through Figure 1 It can be seen that the current flowing through the resistor R2 is I2-I3, which is then converted into a voltage on the resistor R2 to obtain the output voltage V o ,Right now Then, differentiating Vo with respect to temperature gives the following equation:

[0030]

[0031] From the above formula, we can get: the absolute value of Vo's change in temperature is V be The change in temperature is multiplied by the ratio of R2 / R3, which achieves the V be The temperature coefficient of the resistor is directly multiplied by the proportional coefficient of the resistor, that is, the large temperature coefficient (V be The temperature coefficient of deltaVbe is about -1.5MV / ℃, which is more than 17 times of deltaVbe) multiplied by the adjustable resistance ratio, it can easily reach above 10mV / ℃; and because the offset of the operational amplifier and the mismatch of the current mirror have little change with temperature, they are ignored and only related to the ratio of R2 and R3. Therefore, it is only necessary to match the resistance of R2 and R3; and V be The change in temperature with corner is small and can be ignored.

[0032] It should be further explained that in actual temperature detection, factory calibration is first required to record V at room temperature. o The voltage value is V o1 In the on-chip register, this value will vary depending on K′, V os1 , V os2 When measuring temperature normally, only V at the current temperature is needed. o2 Compared with the previous V at room temperature o1 The difference is calculated and divided by the slope (determined by the ratio of R2 and R3) to obtain the temperature deviation from the normal temperature. The final temperature value is the corrected normal temperature plus the calculated temperature deviation.

[0033] It can be seen that the temperature sensor circuit provided in the embodiment of the present application only needs to perform single-point temperature correction, and does not need to perform multi-point measurement to draw the temperature curve, because its slope is not sensitive to process changes, which can greatly save calibration costs. And the temperature sensor circuit can avoid K', V by using the differential idea. os1 , V os2 The impact of this feature is relatively low, and the requirements for layout design are relatively low.

[0034] The embodiment of the present application provides a temperature sensor circuit and a temperature sensor including the temperature sensor circuit. By using V be The temperature coefficient is used for temperature detection. Since it has a large change in temperature, high-sensitivity temperature detection can be achieved. In the embodiment of the present application, the slope is fixed and is not affected by the offset. Therefore, it only needs to be calibrated once at room temperature, and there is no need to measure the temperature curve at multiple temperature points, which greatly saves costs and improves accuracy. The embodiment of the present application can achieve a larger slope through a smaller magnification to improve the sensitivity of the temperature sensor.

[0035] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that an article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such article or device. In the absence of further restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the article or device including the above elements.

[0036] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A temperature sensor circuit, characterized in that: include: Transistors M1-M5, resistors R1-R3, a first operational amplifier OP1, a second operational amplifier OP2 and a triode Q1, wherein: The first end of the transistor M1, the first end of the transistor M2 and the first end of the transistor M3 are connected to VDD respectively, the second end of the transistor M1, the second end of the transistor M2 and the second end of the transistor M3 are connected, the first end of the transistor M1 is connected to the second end of the transistor M1, the common end thereof is connected to the first end of the transistor M4, the second end of the transistor M4 is connected to the output end of the first operational amplifier OP1, the third end of the transistor M4 is connected to the negative input end of the first operational amplifier OP1, and the common end thereof is grounded through a resistor R1, and the positive input end of the first operational amplifier OP1 is connected to the input power supply V1; The third end of the transistor M2 is connected to the first end of the transistor M5, and the common end thereof is grounded through the resistor R2, and the common end thereof serves as the output end of the temperature sensor circuit; the second end of the transistor M5 is connected to the output end of the second operational amplifier OP2, the third end of the transistor M5 is grounded through the resistor R3, the third end of the transistor M5 is connected to the negative input end of the second operational amplifier OP2, the positive input end of the second operational amplifier OP2 is connected to the first end of the triode Q1, the first end of the triode Q1 is connected to the third end of the transistor M3, the second end of the triode Q1 is connected to the third end of the triode Q1, and the common end thereof is grounded; The absolute value of the output voltage V0 at the output end of the temperature sensor circuit changing with temperature is the change of Vbe changing with temperature multiplied by the ratio of the resistance R2 / resistance R3.

2. The temperature sensor circuit according to claim 1, characterized in that: The transistors M1 - M5 are field effect transistors.

3. The temperature sensor circuit according to claim 2, characterized in that: The first end of the transistor M1 - M3 is a source, the second end of the transistor M1 - M3 is a gate, and the third end of the transistor M1 - M3 is a drain.

4. The temperature sensor circuit according to claim 2, characterized in that: The first end of the transistor M4 - M5 is a drain, the second end of the transistor M4 - M5 is a gate, and the third end of the transistor M4 - M5 is a source.

5. The temperature sensor circuit according to claim 1, characterized in that: The transistor Q1 is a PNP transistor.

6. The temperature sensor circuit according to claim 5, characterized in that: The first end of the transistor Q1 is an emitter, the second end of the transistor Q1 is a base, and the third end of the transistor Q1 is a collector.

7. A temperature sensor, characterized in that: It comprises the temperature sensor circuit as described in any one of claims 1 to 6.

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