CN116481664A - Temperature detection circuit - Google Patents

Temperature detection circuit Download PDF

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Publication number
CN116481664A
CN116481664A CN202310078143.3A CN202310078143A CN116481664A CN 116481664 A CN116481664 A CN 116481664A CN 202310078143 A CN202310078143 A CN 202310078143A CN 116481664 A CN116481664 A CN 116481664A
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China
Prior art keywords
electrode
temperature
resistor
temperature detection
emitter
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CN202310078143.3A
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Chinese (zh)
Inventor
刘文韬
康丙寅
杨丰
彭克武
苟超
雷旭
廖鹏飞
黄晓宗
刘婷
曾欣
罗焰娇
陈仕松
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CETC 24 Research Institute
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CETC 24 Research Institute
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Priority to CN202310078143.3A priority Critical patent/CN116481664A/en
Publication of CN116481664A publication Critical patent/CN116481664A/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
    • G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
    • G01K7/18—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer
    • G01K7/20—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer in a specially-adapted circuit, e.g. bridge circuit

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Amplifiers (AREA)

Abstract

The invention belongs to the field of integrated circuits, and particularly relates to a temperature detection circuit, which comprises: an external temperature detection resistor network, a temperature detection operational amplifier, a level shift circuit and a temperature detection module; the external temperature detection resistor network generates a voltage signal changing along with the temperature according to the external temperature, and inputs the voltage signal into the temperature detection operational amplifier; the temperature detection operational amplifier converts the voltage signal into a current signal changing along with the temperature; the level shift circuit converts the current signal into a voltage signal, superimposes the converted voltage signal with the basic signal, and inputs the superimposed signal into the temperature detection module to obtain a temperature detection result; the temperature detection circuit structure of the invention is different from the traditional device adopting the triode VBE as the temperature detection, and ensures the sampling precision by externally connecting a special linearized temperature-sensitive resistor sampling network.

Description

Temperature detection circuit
Technical Field
The invention belongs to the field of integrated circuits, and particularly relates to a temperature detection circuit.
Background
In power integrated circuits, relatively accurate temperature sensing is involved when the device is operating at different temperatures, in order to compensate for drift in stability or performance of the circuit caused by the different temperatures. Therefore, a more accurate temperature detection circuit is needed, and the temperature detection circuit is converted into a current signal or a voltage signal which is converted with temperature and transmitted to a later stage.
The traditional temperature detection circuit is characterized in that bias current is designed to flow through a triode Q1, then the voltage difference between the base electrode and the emitter electrode of the triode is used for obtaining the detected temperature according to the characteristics of the triode; where VBE has a negative temperature coefficient, typically-2 mV/. Degree.C. The conventional method for detecting the temperature of the VBE voltage is generally simple in circuit implementation and can be used as a protection circuit such as an over-temperature protection unit.
However, in the conventional temperature detection method, the temperature coefficient of VBE is deviated along with the manufacturing process, so that the accuracy of the temperature detection circuit is poor, which is not beneficial to the application in circuits with high requirements on temperature change.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a relatively accurate temperature detection circuit which is used for temperature compensation of peak current limiting points at different temperatures in a PWM controller.
A temperature detection circuit, comprising: an external temperature detection resistor network, a temperature detection operational amplifier, a level shift circuit and a temperature detection module; the external temperature detection resistor network generates a voltage signal changing along with the temperature according to the external temperature, and inputs the voltage signal into the temperature detection operational amplifier; the temperature detection operational amplifier converts the voltage signal into a current signal changing along with the temperature; the level shift circuit converts the current signal into a voltage signal, superimposes the converted voltage signal with the basic signal, and inputs the superimposed signal into the temperature detection module to obtain a temperature detection result;
the temperature detection operational amplifier comprises PMOS tubes M21, M22, M23, M24 and M25, resistors R1 and R2, NPN tubes Q21, Q22 and Q23, LPNP tubes Q24 and Q25 and constant current source biases Is and IB1; the source electrode of M21 is connected with the power supply end VIN, the grid electrode and the drain electrode are respectively connected with the grid electrode of M22 and the grid electrode of M23 after being short-circuited, and the drain electrode is connected with one end of the constant current source bias IB1; the other end of the constant current source bias IB1 is grounded; the source electrode of M22 is connected with the power supply end VIN, and the drain electrode is respectively connected with the base electrode of Q21, the collector electrode of Q21 and the base electrode of Q22; one end of an emitter electrode of the Q21 is connected with an emitter electrode of the Q23 through a resistor R1 respectively; the other end of the resistor R1 is connected with the emitter of the Q24; the collector of Q24 Is grounded, and the base Is respectively connected with the port ITEMP and the constant current source Is; the source electrode of M23 is connected with the power supply end VIN, and the drain electrode is respectively connected with the base electrode of Q23 and the collector electrode of Q22; the emitter of the Q22 is connected with one end of a resistor R2, and the other end of the resistor R2 is respectively connected with the emitter of the Q25 and the drain electrode of the M25; the base electrode of the Q25 is connected with the reference voltage input port, and the collector electrode is grounded; the source electrode of M24 is connected with the power supply terminal VIN, and the grid electrode and the drain electrode of M24 are connected with the grid electrode of M25 and the collector electrode of Q23 respectively.
Preferably, the external temperature detection resistor network comprises an NTC temperature sensitive resistor R NTC Resistor R3 and resistor R4; NTC temperature-sensitive resistor R NTC The resistor R3 is connected in series with the resistor R4 in parallel; the other end of the resistor R3 is connected with a temperature detection operational amplifier.
Preferably, the level shift circuit comprises PMOS tubes M26 and M27, a resistor R5, NPN tubes Q26 and Q27; the source electrode of the PMOS tube M26 is connected with the power supply end VIN, the grid electrode is connected with the grid electrode of the PMOS tube M27, and the drain electrode is respectively connected with the collector electrode of the PMOS tube Q26, the base electrode of the PMOS tube Q26 and the base electrode of the PMOS tube Q27; the emitter of Q26 is grounded; the source electrode of M27 is connected with the power supply end VIN, and the drain electrode of M27 is connected with one end of the resistor R5; the collector of the other end Q27 of the resistor R5 is connected; the emitter of Q27 is grounded.
Further, the drain electrode of the PMOS transistor M27 in the level shift circuit is used as the signal output terminal V1 of the level shift circuit; the collector of NPN transistor Q27 serves as the bi-directional port Vbase end of the level shift circuit.
The invention has the beneficial effects that:
the temperature detection circuit structure is different from the traditional device adopting the triode VBE as the temperature detection, and the sampling precision is ensured by externally connecting a special linearized temperature-sensitive resistor sampling network; the invention converts the sampled temperature information into a current signal in a negative feedback mode of the operational amplifier, and converts the current signal through a complex ADC circuit, thereby ensuring the precision and simultaneously having simpler structure.
Drawings
FIG. 1 is a schematic diagram of an external linearization resistor network of the invention;
FIG. 2 is a block diagram of a temperature detection circuit according to the present invention;
FIG. 3 is a graph of port voltage versus temperature for the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
A temperature sensing circuit, the circuit comprising: an external temperature detection resistor network, a temperature detection operational amplifier, a level shift circuit and a temperature detection module; the external temperature detection resistor network generates a voltage signal changing along with the temperature according to the external temperature, and inputs the voltage signal into the temperature detection operational amplifier; the temperature detection operational amplifier converts the voltage signal into a current signal changing along with the temperature; the level shift circuit converts the current signal into a voltage signal, superimposes the converted voltage signal with the basic signal, and inputs the superimposed signal into the temperature detection module to obtain a temperature detection result.
Fig. 1 shows the environment in which the temperature detection circuit is used in a PWM controller circuit for temperature compensation of peak current limits of a DC-DC converter circuit at different temperatures. The converter is externally connected with a temperature compensation network, also called an external temperature detection resistor network 1, through an ITEMP pin to detect the temperature.
In this embodiment, the external temperature detection resistor network includes an NTC temperature sensitive resistor R NTC Resistor R3 and resistor R4; NTC temperature-sensitive resistor R NTC The resistor R3 is connected in series with the resistor R4 in parallel; NTC temperature-sensitive resistor R NTC The other end connected in parallel with the resistor R4 is grounded. The other end of the resistor R3 is connected with a temperature detection operational amplifier.
Aiming at the partial circuit of the external temperature detection resistor network, the sampling of the RNTC resistor is linearized through the resistors R3 and R4, so that the accuracy of temperature sampling information is ensured.
The expression of the resistance of the NTC temperature-sensitive resistor at the temperature T is as follows:
wherein R is T0 Is R at a temperature T0=25℃ NTC Resistance value of (2); beta is the material characteristic constant of the temperature sensitive resistor, the unit is K, and T represents the current temperature.
The outflow constant current source Is inside the itimp port flows into the external temperature detection resistor network 1, and the obtained port voltage VTEMP Is:
in the formula, linearization of the VTEMP is realized through the introduction of the R4 resistor, specifically, taylor formula expansion is carried out on the formula of the VTEMP, so that the high-level small quantity of the formula of the VTEMP on the temperature is zero, and the required resistance values of the R4 resistor and the R3 resistor can be obtained through calculation.
In this embodiment, as shown in fig. 2, the temperature detection op-amp includes PMOS transistors M21, M22, M23, M24, M25, resistors R1, R2, NPN transistors Q21, Q22, Q23, LPNP transistors Q24, Q25, constant current source bias Is, IB1; the source electrode of M21 is connected with the power supply end VIN, the grid electrode and the drain electrode are respectively connected with the grid electrode of M22 and the grid electrode of M23 after being short-circuited, and the drain electrode is connected with one end of the constant current source bias IB1; the other end of the constant current source bias IB1 is grounded; the source electrode of M22 is connected with the power supply end VIN, and the drain electrode is respectively connected with the base electrode of Q21, the collector electrode of Q21 and the base electrode of Q22; one end of an emitter electrode of the Q21 is connected with an emitter electrode of the Q23 through a resistor R1 respectively; the other end of the resistor R1 is connected with the emitter of the Q24; the collector of Q24 Is grounded, and the base Is respectively connected with the port ITEMP and the constant current source Is; the source electrode of M23 is connected with the power supply end VIN, and the drain electrode is respectively connected with the base electrode of Q23 and the collector electrode of Q22; the emitter of the Q22 is connected with one end of a resistor R2, and the other end of the resistor R2 is respectively connected with the emitter of the Q25 and the drain electrode of the M25; the base electrode of the Q25 is connected with the reference voltage input port, and the collector electrode is grounded; the source electrode of M24 is connected with the power supply terminal VIN, and the grid electrode and the drain electrode of M24 are connected with the grid electrode of M25 and the collector electrode of Q23 respectively.
For the 'VITEMP temperature detection operational amplifier' part circuit, Q24 and Q25 are respectively the positive input end and the negative input end of the operational amplifier, the bias currents of the M21 branches of the PMOS tubes M22 and M23 are mirrored, and the mirroring ratio is 1:1. The Q21 and Q22 tube form a clamp circuit that clamps the same emitter voltages, i.e., the voltages at points a and B in fig. 2. The emitter of Q23 is fed back to one end of the resistor of the Q24 input branch to form a negative feedback structure.
For the branch where Q21 is located, the voltage node equation is given by:
V A ＝V ITEMP +Vbe Q24 +(I SET +I DM22 )·R
wherein V is ITEMP Representing the voltage signal, vbe, converted from the temperature sampling signal outside the device Q24 Represents the emitter junction voltage drop of Q24, I SET Representing the current that Q23 feeds back to the emitter of Q21,I DM22 the current flowing through M22 is shown, and R is the resistance of resistor R1.
For the branch where Q22 is located, the voltage node equation is given by:
V B ＝V+Vbe Q25 +I DM23 ·R x
wherein V represents the reference voltage, vbe Q25 Represents the emitter junction voltage drop of Q25, I DM23 Represents the current flowing through M23, R x The resistance value of the resistor R2 is shown.
Because the bias current of the branch of the M21 is mirrored by the PMOS tubes M22 and M23, and the mirroring ratio is 1:1, the currents flowing through the M22 and M23 are equal. And M24 and M25 are mirror image tubes, and the mirror image proportion is 1:1. Resulting in equal emitter currents through Q24 and Q25, as well as equal VBE voltages. The emitter current ISET flowing through Q23 is obtained from the voltage of the branch where Q21 is located and the voltage of the branch where Q22 is located as:
the temperature compensation occurs on the premise that VITEMP should be less than 0.5V reference voltage.
In this embodiment, the level shift circuit includes PMOS transistors M26 and M27, a resistor R5, and NPN transistors Q26 and Q27; the source electrode of the PMOS tube M26 is connected with the power supply end VIN, the grid electrode is connected with the grid electrode of the PMOS tube M27, and the drain electrode is respectively connected with the collector electrode of the PMOS tube Q26, the base electrode of the PMOS tube Q26 and the base electrode of the PMOS tube Q27; the emitter of Q26 is grounded; the source electrode of M27 is connected with the power supply end VIN, and the drain electrode of M27 is connected with one end of the resistor R5; the collector of the other end Q27 of the resistor R5 is connected; the emitter of Q27 is grounded.
For the "vitamp level shift circuit" part of the circuit, the vitamp mapped current signal ISET is mirrored through M24 to the vitamp level shift circuit consisting of M26, M27, Q26, Q27, whose output voltage V1 is:
wherein, vbase is the constant bias voltage given by the outside, and the temperature coefficient is smaller.
Simplifying the output voltage V1 according to the emitter current ISET flowing through Q23 to obtain:
according to the expression, a negative feedback structure of the operational amplifier can be obtained, an external linearized voltage signal VTEMP which changes along with the temperature is converted into a current signal ISET which changes along with the temperature, and the ISET current signal is converted into a voltage signal through a VITEMP level shift circuit and then is superimposed on a basic signal to be sent into a later-stage control circuit.
As shown in fig. 3, the result of linearizing the NTC resistor after having a normal temperature resistance of 275kΩ is shown, and it can be seen that the voltage value of the detected VTEMP decreases linearly with the increase of temperature, which is consistent with the theoretical calculation. The deviation is mainly caused by the deviation between the actual value and the theoretical value of the temperature-sensitive resistor RNTC.
While the foregoing is directed to embodiments, aspects and advantages of the present invention, other and further details of the invention may be had by the foregoing description, it will be understood that the foregoing embodiments are merely exemplary of the invention, and that any changes, substitutions, alterations, etc. which may be made herein without departing from the spirit and principles of the invention.

Claims (9)

1. A temperature detection circuit, comprising: an external temperature detection resistor network, a temperature detection operational amplifier, a level shift circuit and a temperature detection module; the external temperature detection resistor network generates a voltage signal changing along with the temperature according to the external temperature, and inputs the voltage signal into the temperature detection operational amplifier; the temperature detection operational amplifier converts the voltage signal into a current signal changing along with the temperature; the level shift circuit converts the current signal into a voltage signal, superimposes the converted voltage signal with the basic signal, and inputs the superimposed signal into the temperature detection module to obtain a temperature detection result;
the temperature detection operational amplifier comprises PMOS tubes M21, M22, M23, M24 and M25, resistors R1 and R2, NPN tubes Q21, Q22 and Q23, LPNP tubes Q24 and Q25 and constant current source biases Is and IB1; the source electrode of M21 is connected with the power supply end VIN, the grid electrode and the drain electrode are respectively connected with the grid electrode of M22 and the grid electrode of M23 after being short-circuited, and the drain electrode is connected with one end of the constant current source bias IB1; the other end of the constant current source bias IB1 is grounded; the source electrode of M22 is connected with the power supply end VIN, and the drain electrode is respectively connected with the base electrode of Q21, the collector electrode of Q21 and the base electrode of Q22; one end of an emitter electrode of the Q21 is connected with an emitter electrode of the Q23 through a resistor R1 respectively; the other end of the resistor R1 is connected with the emitter of the Q24; the collector of Q24 Is grounded, and the base Is respectively connected with the port ITEMP and the constant current source Is; the source electrode of M23 is connected with the power supply end VIN, and the drain electrode is respectively connected with the base electrode of Q23 and the collector electrode of Q22; the emitter of the Q22 is connected with one end of a resistor R2, and the other end of the resistor R2 is respectively connected with the emitter of the Q25 and the drain electrode of the M25; the base electrode of the Q25 is connected with the reference voltage input port, and the collector electrode is grounded; the source electrode of M24 is connected with the power supply terminal VIN, and the grid electrode and the drain electrode of M24 are connected with the grid electrode of M25 and the collector electrode of Q23 respectively.
2. A temperature detection circuit according to claim 1, wherein the external temperature detection resistor network comprises an NTC temperature sensitive resistor R NTC Resistor R3 and resistor R4; NTC temperature-sensitive resistor R NTC The resistor R3 is connected in series with the resistor R4 in parallel; the other end of the resistor R3 is connected with a temperature detection operational amplifier.
3. A temperature detection circuit according to claim 1, wherein the NTC temperature sensitive resistor R NTC The resistance of (2) is:
wherein R is T0 Indicating a temperature at T 0 R is time R NTC Beta represents the material characteristic constant of the temperature sensitive resistor, and T represents the current temperature.
4. The temperature detection circuit according to claim 1, wherein the level shift circuit comprises PMOS transistors M26 and M27, a resistor R5, NPN transistors Q26 and Q27; the source electrode of the PMOS tube M26 is connected with the power supply end VIN, the grid electrode is connected with the grid electrode of the PMOS tube M27, and the drain electrode is respectively connected with the collector electrode of the PMOS tube Q26, the base electrode of the PMOS tube Q26 and the base electrode of the PMOS tube Q27; the emitter of Q26 is grounded; the source electrode of M27 is connected with the power supply end VIN, and the drain electrode of M27 is connected with one end of the resistor R5; the collector of the other end Q27 of the resistor R5 is connected; the emitter of Q27 is grounded.
5. The temperature detecting circuit according to claim 4, wherein a drain electrode of the PMOS transistor M27 in the level shift circuit is used as a signal output terminal V1 of the level shift circuit; the collector of NPN transistor Q27 serves as the bi-directional port Vbase end of the level shift circuit.
6. The temperature sensing circuit of claim 5, wherein the output voltage at the signal output terminal V1 of the level shift circuit is:
V 1 ＝V base +I SET ×R m .
wherein V is base For a constant bias voltage given externally, I SET For detecting the current output by the operational amplifier for temperature, R m The resistance of the resistor R5 is shown.
7. The temperature sensing circuit of claim 4, wherein the level shift circuit is interconnected with the temperature sensing op-amp connection comprising: and connecting an M26 grid electrode and an M27 grid electrode of the level shift circuit and then connecting an M24 grid electrode and a drain electrode of the temperature detection operational amplifier to form a current mirror structure.
8. The temperature detecting circuit according to claim 1, wherein a voltage calculation formula for a branch where Q21 is located of the temperature detecting op-amp is:
V A ＝V ITEMP +Vbe Q24 +(I SET +I DM22 )·R
wherein,,V ITEMP representing the voltage signal, vbe, converted from the temperature sampling signal outside the device Q24 Represents the emitter junction voltage drop of Q24, I SET Representing the current fed back by Q23 to the emitter of Q21, I DM22 The current flowing through M22 is shown, and R is the resistance of resistor R1.
9. The temperature detecting circuit according to claim 1, wherein a voltage calculation formula of the temperature detecting operational amplifier for the branch where Q22 is located is:
V B ＝V+Vbe Q25 +I DM23 ·R x
wherein V represents the reference voltage, vbe Q25 Represents the emitter junction voltage drop of Q25, I DM23 Represents the current flowing through M23, R x The resistance value of the resistor R2 is shown.
CN202310078143.3A 2023-01-18 2023-01-18 Temperature detection circuit Pending CN116481664A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310078143.3A CN116481664A (en) 2023-01-18 2023-01-18 Temperature detection circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310078143.3A CN116481664A (en) 2023-01-18 2023-01-18 Temperature detection circuit

Publications (1)

Publication Number Publication Date
CN116481664A true CN116481664A (en) 2023-07-25

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310078143.3A Pending CN116481664A (en) 2023-01-18 2023-01-18 Temperature detection circuit

Country Status (1)

Country Link
CN (1) CN116481664A (en)

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