CMOS temperature sensing front-end circuit with adjustable output voltage range

Abstract

The invention belongs to the field of temperature sensors, and particularly discloses a CMOS temperature sensing front-end circuit with an adjustable output voltage range, which comprises a temperature sensing module, a bias module, an output module and a power supply module, and is characterized in that the power supply module is respectively connected with the temperature sensing module, the bias module and the output module, and the temperature sensing module is respectively connected with the bias module and the output module; the bias module is connected with the output module; the power module provides voltage for the temperature sensing module, the bias module and the output module, the temperature sensing module detects temperature and outputs current with a positive temperature coefficient and reference voltage irrelevant to the temperature, and the bias module converts the reference voltage into bias current needed by the output module. And the output module converts the current with the positive temperature coefficient into a controllable voltage with a negative temperature coefficient. According to the invention, the flexible control of the output voltage range is realized, and the precision of the temperature sensor is improved. The invention is suitable for the temperature sensor system.

Description

Technical Field

[0001] The invention belongs to the field of temperature sensors, in particular to a CMOS temperature sensing front-end circuit with adjustable output voltage range. Background Art

[0002] With the continuous development of the semiconductor industry, the integration of chips continues to increase, power consumption increases, and excessive heat generation of chips has become an important factor limiting their performance. In order to detect the internal temperature of the chip to improve the reliability of the chip, on-chip integrated temperature sensors are currently used. Integrated temperature sensors not only have high integration and small area, but also have the advantages of high accuracy, low power consumption, low cost, and direct digital output.

[0003] The temperature sensing front end is an important part of the temperature sensor. It is a module in the entire temperature sensor system that converts temperature information into voltage signals or time domain signals. Its performance will directly affect the performance of the temperature sensor system. The method of using voltage signals to represent temperature information has higher accuracy and resolution and is more widely used. However, the output range of this method is small, which is not conducive to improving system accuracy. How to increase the output range of the voltage domain temperature sensing front end and thus improve system accuracy is an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to provide a CMOS temperature sensing front-end circuit with an adjustable output voltage range, so as to achieve flexible control of the output voltage range and improve the accuracy of the temperature sensor.

[0005] In order to achieve the above-mentioned purpose, the technical methods adopted by the present invention are as follows:

[0006] A CMOS temperature sensing front-end circuit with adjustable output voltage range comprises a temperature sensing module, a bias module, an output module and a power module. The power module is respectively connected to the temperature sensing module, the bias module and the output module. The temperature sensing module is respectively connected to the bias module and the output module. The bias module is connected to the output module. The power module provides voltage for the temperature sensing module, the bias module and the output module. The temperature sensing module detects temperature and outputs a current with a positive temperature coefficient and a reference voltage that is independent of temperature. The bias module converts the reference voltage into a bias current required by the output module. The output module converts the current with a positive temperature coefficient into a controllable voltage with a negative temperature coefficient.

[0007] As a limitation: the temperature sensing module includes a first diode, N second diodes, a third diode, a first resistor, a second resistor, a first MOS tube, a second MOS tube, a third MOS tube, a fourth MOS tube, a fifth MOS tube, a sixth MOS tube, M seventh MOS tubes, M eighth MOS tubes, a ninth MOS tube and a tenth MOS tube; the sources of the first MOS tube, the third MOS tube, the fifth MOS tube and the M seventh MOS tubes are all connected to the power module, the first MOS tube, the third MOS tube, the fifth MOS tube and the M seventh MOS tubes share a gate, the drain of the first MOS tube is connected to the source of the second MOS tube, the drain of the third MOS tube is respectively connected to the gate of the third MOS tube and the source of the fourth MOS tube, the drain of the fifth MOS tube is connected to the source of the sixth MOS tube, the drain of each seventh MOS tube is connected to the source of the eighth MOS tube, and the M seventh MOS tubes are connected one by one with the M eighth MOS tubes. The second MOS tube, the fourth MOS tube, the sixth MOS tube and the M eighth MOS tubes share a common gate, the drain of the second MOS tube is respectively connected to the drain of the ninth MOS tube and the gate of the ninth MOS tube, the drain of the fourth MOS tube is respectively connected to the gate of the fourth MOS tube and the drain of the tenth MOS tube, the drain of the sixth MOS tube is connected to one end of the second resistor, the drains of the M eighth MOS tubes are connected to output a current with a positive temperature coefficient, and a reference voltage that is independent of temperature is output between the drain of the sixth MOS tube and the second resistor; the ninth MOS tube and the tenth MOS tube share a common gate, the source of the ninth MOS tube is connected to the positive electrode of the first diode, the source of the tenth MOS tube is connected to one end of the first resistor, the other end of the first resistor is respectively connected to the positive electrodes of the N second diodes, the other end of the second resistor is connected to the positive electrode of the third diode, and the cathode of the first diode, the cathode of the N second diodes and the cathode of the third diode are all grounded.

[0008] As a limitation: the bias module includes a first operational amplifier, an eleventh MOS tube, a twelfth MOS tube, a thirteenth MOS tube, a fourteenth MOS tube, L fifteenth MOS tubes, L sixteenth MOS tubes, a third resistor, a fourth resistor and a fifth resistor. The reference voltage output by the temperature sensing module is input to the non-inverting input terminal of the first operational amplifier. The output terminal of the first operational amplifier is respectively connected to the gate of the eleventh MOS tube and the gate of the L fifteenth MOS tubes. The eleventh MOS tube and the L fifteenth MOS tubes share a common gate. The source of the eleventh MOS tube, the source of the L fifteenth MOS tubes and the source of the thirteenth MOS tube are all connected to the power module. The drain of the eleventh MOS tube is connected to the source of the twelfth MOS tube. Each fifteenth MOS tube is connected to the power module. The drains of the S tubes are all connected to the source of the sixteenth MOS tube, the L fifteenth MOS tubes correspond to the L sixteenth MOS tubes one by one, the drains of the thirteenth MOS tube are respectively connected to the gate of the thirteenth MOS tube and the source of the fourteenth MOS tube, the twelfth MOS tube, the fourteenth MOS tube and the L sixteenth MOS tubes share a gate, the drain of the twelfth MOS tube is respectively connected to the inverting input terminal of the first operational amplifier and one end of the third resistor, the drain of the fourteenth MOS tube is respectively connected to the gate of the fourteenth MOS tube and one end of the fifth resistor, the drains of the L sixteenth MOS tubes are connected to the bias current required by the output module, the other end of the third resistor is connected to one end of the fourth resistor, and the other end of the fourth resistor and the other end of the fifth resistor are both grounded.

[0009] As a limitation: the output module includes a second operational amplifier, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor, the power supply module is connected to one end of the ninth resistor, the other end of the ninth resistor is respectively connected to one end of the tenth resistor and the in-phase input end of the second operational amplifier, the other end of the tenth resistor is grounded, the output voltage of the power supply module generates a bias voltage through resistance voltage division and is input to the in-phase input end of the second operational amplifier, the bias module provides a bias current for the second operational amplifier, the output end of the second operational amplifier is connected to one end of the sixth resistor, the other end of the sixth resistor is respectively connected to the inverting input end of the second operational amplifier and one end of the seventh resistor, the other end of the seventh resistor is connected to one end of the eighth resistor, the other end of the eighth resistor is grounded, the current with a positive temperature coefficient output by the temperature sensing module is input between the seventh resistor and the eighth resistor, the resistance ratio between the sixth resistor, the seventh resistor and the eighth resistor is adjustable, the resistance ratio between the ninth resistor and the tenth resistor is adjustable, and the output end of the second operational amplifier outputs a controllable voltage with a negative temperature coefficient.

[0010] As a qualification: the power module includes an LDO linear regulator, which converts an input voltage into a stable output voltage.

[0011] Due to the adoption of the above scheme, the present invention has the following beneficial effects compared with the prior art:

[0012] The present invention provides a CMOS temperature sensing front-end circuit with adjustable output voltage range. The temperature sensing module, a bias module, an output module and a power supply module are arranged to cooperate with each other to convert temperature information into a voltage signal. The resistance ratio between resistors in the output module is adjusted to achieve flexible control of the output voltage range and improve the accuracy of the temperature sensor. The temperature sensing module detects temperature by utilizing the characteristic that the voltage across the diode changes with temperature, and by arranging two groups of current mirrors and two resistors, the generation and output of a positive temperature coefficient current and the generation and output of a reference voltage that is independent of temperature are achieved. The bias circuit converts the reference voltage into a bias current by arranging a first operational amplifier and three resistors, and provides a stable bias current for the output module through a group of current mirrors. The output module converts the current with a positive temperature coefficient into a voltage with a negative temperature coefficient by arranging a second operational amplifier circuit and two groups of resistors, and by adjusting the resistance ratio between a sixth resistor, a seventh resistor and an eighth resistor, and the resistance ratio between a ninth resistor and a tenth resistor, the flexible control of the output voltage range is achieved and the accuracy of the temperature sensor is improved. The LDO linear regulator is arranged to provide a stable voltage for the temperature sensing module, the bias module and the output module.

[0013] The present invention is applicable to a temperature sensor system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] Figure 1 This is a structural block diagram of a CMOS temperature sensing front-end circuit with adjustable output voltage range according to an embodiment of the present invention;

[0016] Figure 2 is a circuit diagram of a temperature sensing module according to an embodiment of the present invention;

[0017] Figure 3 is a circuit diagram of a bias module according to an embodiment of the present invention;

[0018] Figure 4 A circuit diagram of an output module according to an embodiment of the present invention;

[0019] Figure 5 The figure is a simulation result of the output voltage of the output module when the resistance ratios in the output module are different according to the embodiment of the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with embodiments, but those skilled in the art should understand that the present invention is not limited to the following embodiments, and any improvements and equivalent changes made based on the specific embodiments of the present invention are within the scope of protection of the claims of the present invention.

[0021] Embodiment A CMOS temperature sensing front-end circuit with adjustable output voltage range

[0022] A CMOS temperature sensing front-end circuit with adjustable output voltage range, such as Figure 1 As shown, it includes a temperature sensing module, a bias module, an output module and a power module. The power module is connected to the temperature sensing module, the bias module and the output module respectively. The temperature sensing module is connected to the bias module and the output module respectively. The bias module is connected to the output module. The power module provides a voltage V for the temperature sensing module, the bias module and the output module. LDO The temperature sensing module detects the temperature and outputs a current I with a positive temperature coefficient temp and a temperature-independent reference voltage V REF , the bias module sets the reference voltage V REF Converted into the bias current I required by the output module bias , the output module will be positive temperature coefficient current I temp Converted into a controllable voltage V with a negative temperature coefficient temp .

[0023] The power module includes an LDO linear regulator, which converts the input voltage into a stable output voltage V LDO .

[0024] like Figure 2 As shown, the temperature sensing module includes a first diode D1, N second diodes D2, a third diode D3, a first resistor R1, a second resistor R2, a first MOS tube M1, a second MOS tube M2, a third MOS tube M3, a fourth MOS tube M4, a fifth MOS tube M5, a sixth MOS tube M6, M seventh MOS tubes M7, M eighth MOS tubes M8, a ninth MOS tube M9 and a tenth MOS tube M 10 The source electrodes of the first MOS tube M1, the third MOS tube M3, the fifth MOS tube M5 and the M seventh MOS tubes M7 are all input with the voltage V provided by the LDO linear regulator. LDO, the first MOS tube M1, the third MOS tube M3, the fifth MOS tube M5 and the M seventh MOS tubes M7 share a gate, the drain of the first MOS tube M1 is connected to the source of the second MOS tube M2, the drain of the third MOS tube M3 is respectively connected to the gate of the third MOS tube M3 and the source of the fourth MOS tube M4, the drain of the fifth MOS tube M5 is connected to the source of the sixth MOS tube M6, the drain of each seventh MOS tube M7 is connected to the source of the eighth MOS tube M8, and the M seventh MOS tubes M7 correspond to the M eighth MOS tubes M8 one by one; the second MOS tube M2, the fourth MOS tube M4, the sixth MOS tube M6 and the M eighth MOS tubes M8 share a gate, the drain of the second MOS tube M2 is respectively connected to the drain of the ninth MOS tube M9 and the gate of the ninth MOS tube M9, the drain of the fourth MOS tube M4 is respectively connected to the gate of the fourth MOS tube M4 and the gate of the tenth MOS tube M8. 10 The drain of the sixth MOS tube M6 is connected to one end of the second resistor R2, and the drains of the M eighth MOS tubes M8 are connected to output a current I with a positive temperature coefficient. temp A reference voltage V that is independent of temperature is output between the drain of the sixth MOS tube M6 and the second resistor R2. REF ; The ninth MOS tube M9 and the tenth MOS tube M 10 The source of the ninth MOS tube M9 is connected to the anode of the first diode D1, and the tenth MOS tube M 10 The source is connected to one end of the first resistor R1, the other end of the first resistor R1 is respectively connected to the anodes of N second diodes D2, the other end of the second resistor R2 is connected to the anode of the third diode D3, and the cathode of the first diode D1, the cathodes of the N second diodes D2 and the cathode of the third diode D3 are all grounded.

[0025] The voltage difference between the two ends of the first diode D1 and the two ends of the second diode D2 in the temperature sensing module acts on the two ends of the first resistor R1 to generate a current I with a positive temperature coefficient. ptat , I ptat The calculation formula is:

[0026]

[0027] Where k is the Boltzmann constant, q is the electron charge, and T is the absolute temperature;

[0028] Output current I with positive temperature coefficient through current mirror temp :

[0029]

[0030] Current I in the temperature sensing module ptat The current is mirrored to the branch where the second resistor R2 is located, generating a reference voltage V that is independent of temperature.REF , V REF The calculation formula is:

[0031]

[0032] Where V D3 is the voltage difference across the third diode D3.

[0033] like Figure 3 As shown, the bias module includes a first operational amplifier OP1, an eleventh MOS tube M 11 12th MOS tube M 12 、Thirteenth MOS tube M 13 、14th MOS tube M 14 、L fifteenth MOS tubes M 15 , L sixteenth MOS tubes M 16 , the third resistor R3, the fourth resistor R4 and the fifth resistor R5, the reference voltage V output by the temperature sensing module REF The first operational amplifier OP1 is input to the non-inverting input terminal, and the output terminal of the first operational amplifier OP1 is connected to the eleventh MOS transistor M 11 The gate and L fifteenth MOS tube M 15 The gate connection of the eleventh MOS tube M 11 and L fifteenth MOS tubes M 15 Common gate, eleventh MOS tube M 11 The source of L fifteenth MOS tubes M 15 The source and the thirteenth MOS tube M 13 The source of the input LDO linear regulator provides a voltage V LDO , the eleventh MOS tube M 11 The drain of the twelfth MOS tube M 12 The source of each fifteenth MOS tube M 15 The drain of the sixteenth MOS tube M 16 The source of L fifteenth MOS tube M 15 and L sixteenth MOS tubes M 16 One-to-one correspondence, the thirteenth MOS tube M 13 The drain of the thirteenth MOS tube M 13 The gate and the fourteenth MOS tube M 14 The source of the twelfth MOS tube M 12 、14th MOS tube M 14 and L sixteenth MOS tubes M 16 Common gate, 12th MOS tube M 12 The drain of the fourteenth MOS tube M is connected to the inverting input terminal of the first operational amplifier OP1 and one end of the third resistor R3 respectively.14 The drain of the fourteenth MOS tube M 14 The gate of the L sixteenth MOS tube M is connected to one end of the fifth resistor R5. 16 The output module needs a bias current I bias The other end of the third resistor R3 is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 and the other end of the fifth resistor R5 are both grounded.

[0034] The reference voltage V is input to the non-inverting input terminal of the first operational amplifier OP1 in the bias module. REF , using the virtual short characteristic of the operational amplifier and the resistor to generate a current, and then output the bias current I through the current mirror bias The third resistor R3 and the fourth resistor R4 can be selected from resistor types with different temperature coefficients to obtain a bias current I that is independent of temperature. bias , I bias The calculation formula is:

[0035]

[0036] like Figure 4 As shown, the output module includes a second operational amplifier OP2, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9 and a tenth resistor R 10 The power module is connected to one end of the ninth resistor R9, and the other end of the ninth resistor R9 is connected to the tenth resistor R 10 One end of the tenth resistor R is connected to the non-inverting input terminal of the second operational amplifier OP2. 10 The other end is grounded, and the voltage V provided by the LDO linear regulator LDO Generate bias voltage V through resistor voltage division bias The bias module provides a bias current I for the second operational amplifier OP2. bias The output end of the second operational amplifier OP2 is connected to one end of the sixth resistor R6, the other end of the sixth resistor R6 is respectively connected to the inverting input end of the second operational amplifier OP2 and one end of the seventh resistor R7, the other end of the seventh resistor R7 is connected to one end of the eighth resistor R8, the other end of the eighth resistor R8 is grounded, and the current I with a positive temperature coefficient output by the temperature sensing module is input between the seventh resistor R7 and the eighth resistor R8. temp The resistance ratio between the sixth resistor R6, the seventh resistor R7 and the eighth resistor R8 is adjustable, and the ninth resistor R9 and the tenth resistor R 10 The resistance ratio between them is adjustable, and the output end of the second operational amplifier OP2 outputs a controllable voltage V with a negative temperature coefficient. temp .

[0037] The voltage V output by the LDO linear regulator in the output module LDO The ninth resistor R9 and the tenth resistor R 10 The bias voltage V is generated by voltage division bias , bias voltage V bias The bias module provides a bias current I for the second operational amplifier OP2. bias , the current I output by the temperature sensing module temp The voltage V with a negative temperature coefficient and an adjustable voltage range is obtained by calculating the voltage V between the seventh resistor R7 and the eighth resistor R8 through the second operational amplifier OP2. temp ,V temp The calculation formula is:

[0038]

[0039] In the formula, Then I temp Substitute the calculation formula into the above formula and get:

[0040]

[0041] From the above formula, we can see that the output voltage V temp Inversely proportional to the absolute temperature T, so V temp The change of can be used to indicate the change of the current temperature, and by adjusting the resistance ratio between the sixth resistor R6, the seventh resistor R7 and the eighth resistor R8, the ninth resistor R9 and the tenth resistor R 10 The resistance ratio between them is used to achieve the output voltage V temp Range control.

[0042] like Figure 5 As shown in (a), when R6:R7:R8=a:b:c, R6:R7:R8=2a:b:c, and R6:R7:R8=a:2b:c, the output voltage V temp The simulation results from Figure 5 As can be seen from (a), when the resistance ratio of the sixth resistor R6 increases, the output voltage V temp The range becomes larger, when the resistance ratio of the seventh resistor R7 increases, the output voltage V temp The range becomes smaller. Figure 5 (b) shows different V bias When the ninth resistor R9 and the tenth resistor R 10 When the resistance ratio is different, the output module output voltage V temp The simulation results from Figure 5 As can be seen from (b), the output voltage V temp The range will vary with V biasAs V bias becomes smaller and moves downward.

Claims

1. A CMOS temperature sensing front-end circuit with adjustable output voltage range, characterized in that: It includes a temperature sensing module, a bias module, an output module and a power module, the power module is connected to the temperature sensing module, the bias module and the output module respectively, the temperature sensing module is connected to the bias module and the output module respectively, and the bias module is connected to the output module; The power module provides voltage for the temperature sensing module, bias module and output module. The temperature sensing module detects temperature and outputs a current with a positive temperature coefficient and a reference voltage that is independent of temperature. The bias module converts the reference voltage into the bias current required by the output module, and the output module converts the current with a positive temperature coefficient into a controllable voltage with a negative temperature coefficient.

2. A CMOS temperature sensing front-end circuit with adjustable output voltage range according to claim 1, characterized in that: The temperature sensing module includes a first diode, N second diodes, a third diode, a first resistor, a second resistor, a first MOS tube, a second MOS tube, a third MOS tube, a fourth MOS tube, a fifth MOS tube, a sixth MOS tube, M seventh MOS tubes, M eighth MOS tubes, a ninth MOS tube and a tenth MOS tube; the sources of the first MOS tube, the third MOS tube, the fifth MOS tube and the M seventh MOS tubes are all connected to the power module, the first MOS tube, the third MOS tube, the fifth MOS tube and the M seventh MOS tubes share a gate, the drain of the first MOS tube is connected to the source of the second MOS tube, the drain of the third MOS tube is respectively connected to the gate of the third MOS tube and the source of the fourth MOS tube, the drain of the fifth MOS tube is connected to the source of the sixth MOS tube, the drain of each seventh MOS tube is connected to the source of the eighth MOS tube, and the M seventh MOS tubes correspond one to one to the M eighth MOS tubes; The second MOS tube, the fourth MOS tube, the sixth MOS tube and the M eighth MOS tubes share a common gate, the drain of the second MOS tube is respectively connected to the drain of the ninth MOS tube and the gate of the ninth MOS tube, the drain of the fourth MOS tube is respectively connected to the gate of the fourth MOS tube and the drain of the tenth MOS tube, the drain of the sixth MOS tube is connected to one end of the second resistor, the drains of the M eighth MOS tubes are connected to output a current with a positive temperature coefficient, and a reference voltage that is independent of temperature is output between the drain of the sixth MOS tube and the second resistor; the ninth MOS tube and the tenth MOS tube share a common gate, the source of the ninth MOS tube is connected to the positive electrode of the first diode, the source of the tenth MOS tube is connected to one end of the first resistor, the other end of the first resistor is respectively connected to the positive electrodes of the N second diodes, the other end of the second resistor is connected to the positive electrode of the third diode, and the cathode of the first diode, the cathode of the N second diodes and the cathode of the third diode are all grounded.

3. A CMOS temperature sensing front-end circuit with adjustable output voltage range according to claim 1 or 2, characterized in that: The bias module includes a first operational amplifier, an eleventh MOS tube, a twelfth MOS tube, a thirteenth MOS tube, a fourteenth MOS tube, L fifteenth MOS tubes, L sixteenth MOS tubes, a third resistor, a fourth resistor and a fifth resistor. The reference voltage output by the temperature sensing module is input to the in-phase input terminal of the first operational amplifier. The output terminal of the first operational amplifier is respectively connected to the gate of the eleventh MOS tube and the gate of the L fifteenth MOS tubes. The eleventh MOS tube and the L fifteenth MOS tubes share a common gate. The source of the eleventh MOS tube, the source of the L fifteenth MOS tubes and the source of the thirteenth MOS tube are all connected to the power module. The drain of the eleventh MOS tube is connected to the source of the twelfth MOS tube. The drain of each fifteenth MOS tube is connected to the source of the twelfth MOS tube. The drains are all connected to the source of the sixteenth MOS tube, the L fifteenth MOS tubes correspond to the L sixteenth MOS tubes one by one, the drain of the thirteenth MOS tube is respectively connected to the gate of the thirteenth MOS tube and the source of the fourteenth MOS tube, the twelfth MOS tube, the fourteenth MOS tube and the L sixteenth MOS tubes share a gate, the drain of the twelfth MOS tube is respectively connected to the inverting input end of the first operational amplifier and one end of the third resistor, the drain of the fourteenth MOS tube is respectively connected to the gate of the fourteenth MOS tube and one end of the fifth resistor, the drains of the L sixteenth MOS tubes are connected to the bias current required by the output module, the other end of the third resistor is connected to one end of the fourth resistor, and the other end of the fourth resistor and the other end of the fifth resistor are both grounded.

4. A CMOS temperature sensing front-end circuit with adjustable output voltage range according to claim 1 or 2, characterized in that: The output module includes a second operational amplifier, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor. The power supply module is connected to one end of the ninth resistor. The other end of the ninth resistor is respectively connected to one end of the tenth resistor and the in-phase input end of the second operational amplifier. The other end of the tenth resistor is grounded. The output voltage of the power supply module generates a bias voltage through resistance voltage division and inputs it to the in-phase input end of the second operational amplifier. The bias module provides a bias current for the second operational amplifier. The output end of the second operational amplifier is connected to one end of the sixth resistor. The other end of the sixth resistor is respectively connected to the inverting input end of the second operational amplifier and one end of the seventh resistor. The other end of the seventh resistor is connected to one end of the eighth resistor. The other end of the eighth resistor is grounded. The current with a positive temperature coefficient output by the temperature sensing module is input between the seventh resistor and the eighth resistor. The resistance ratio between the sixth resistor, the seventh resistor and the eighth resistor is adjustable. The resistance ratio between the ninth resistor and the tenth resistor is adjustable. The output end of the second operational amplifier outputs a controllable voltage with a negative temperature coefficient.

5. A CMOS temperature sensing front-end circuit with adjustable output voltage range according to claim 1 or 2, characterized in that: The power module includes an LDO linear regulator, which converts the input voltage into a stable output voltage.

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