A temperature sensor circuit

Abstract

This invention discloses a temperature sensor circuit, belonging to the field of semiconductor integrated circuit technology. It includes: a first NMOS transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, an operational amplifier, an analog-to-digital converter (ADC), and a digital logic processing unit. The gate of the first NMOS transistor is connected to a first voltage, the drain is connected to a power supply voltage, and the source is grounded. The substrate is grounded through the first resistor R1 and simultaneously connected to the positive input terminal of the operational amplifier through the second resistor. The inverting input terminal of the operational amplifier is connected to a reference voltage through the third resistor. One end of the fourth resistor is connected to the positive input terminal of the operational amplifier, and the other end is connected to the output terminal of the operational amplifier. The output terminal of the operational amplifier is sequentially connected to both the ADC and the digital logic processing unit before outputting. This invention utilizes the ionization effect of the transistor to construct a temperature detection circuit, resulting in a simple circuit structure and high measurement accuracy.

Description

Technical Field

[0001] This invention relates to the field of semiconductor integrated circuit technology, and in particular to a temperature sensor circuit. Background Technology

[0002] Currently, temperature sensors are widely used in semiconductor integrated circuits to detect on-chip temperatures in instruments and ambient temperatures. Therefore, it is essential to develop high-precision on-chip integrated temperature sensors. Traditional temperature sensor circuits utilize the negative temperature characteristic of diodes (Vbe) for temperature detection, resulting in complex structures and relatively low measurement accuracy. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention utilizes the ionization effect of transistors to construct a temperature detection circuit, which has a simple circuit structure and high measurement accuracy.

[0004] To achieve the above objectives, the present invention provides a temperature sensor circuit, comprising: a first NMOS transistor M1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, an operational amplifier OP, an analog-to-digital converter ADC, and a digital logic processing unit.

[0005] The gate of the first NMOS transistor M1 is connected to the first voltage VG1, the drain is connected to the power supply voltage VDD, the source is grounded, the substrate is grounded through the first resistor R1, and is connected to the positive input terminal of the operational amplifier OP through the second resistor R2.

[0006] The inverting input of the operational amplifier OP is connected to the reference voltage Vref through the third resistor R3;

[0007] The fourth resistor R4 is connected at one end to the positive input terminal of the operational amplifier OP and at the other end to the output terminal of the operational amplifier OP.

[0008] The output of the operational amplifier OP is connected in sequence to both the analog-to-digital converter (ADC) and the digital logic processing unit before outputting.

[0009] Furthermore, the reference voltage Vref is the voltage corresponding to a predetermined temperature.

[0010] Furthermore, it also includes: the second NMOS transistor M2 and the fifth resistor R5;

[0011] The gate of the second NMOS transistor M2 is connected to the second voltage VG2, the drain is connected to the power supply voltage VDD, the source is grounded, and the substrate is grounded through the fifth resistor R5. At the same time, the reference voltage Vref is connected to the inverting input terminal of the operational amplifier OP through the third resistor R3.

[0012] Furthermore, the resistance value of the first resistor R1 is equal to the resistance value of the fifth resistor R5.

[0013] Furthermore, the first NMOS transistor M1 is placed in the temperature region to be tested, and the second NMOS transistor M2 is placed in the constant temperature region.

[0014] Furthermore, the first voltage VG1 and the second voltage VG2 are equal.

[0015] Furthermore, the resistance value of the second resistor R2 is equal to the resistance value of the third resistor R3.

[0016] The beneficial effects of this invention are:

[0017] This invention utilizes the ionization effect of transistors to construct a temperature detection circuit, which has a simple circuit structure and high measurement accuracy. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the temperature sensor circuit structure according to an embodiment of the present invention.

[0019] Figure 2 Transistor substrate voltage V B A diagram illustrating the relationship between temperature and temperature.

[0020] Figure 3 This is another schematic diagram of the temperature sensor circuit according to an embodiment of the present invention. Detailed Implementation

[0021] The present invention will be further explained and described below with reference to the accompanying drawings and embodiments.

[0022] This invention utilizes the ionization effect of transistors to construct a temperature detection circuit. The principle is as follows: when a MOS transistor (especially an NMOS) operates at its drain-source voltage... V DS In high-energy scenarios, a strong electric field forms in the channel region near the drain. Electrons in the channel gain high energy under the acceleration of this strong electric field, becoming "hot electrons." When these hot electrons collide with lattice atoms, they break the Si-Si covalent bonds, generating new electron-hole pairs (i.e., collisional ionization). Electrons are collected by the drain, forming part of the drain current; holes are collected by the substrate, forming the substrate current. I DB Its current characteristics can be described by an empirical model:

[0023]

[0024] in: K 1. K 2 represents the process parameters. V DSThis is the voltage between the drain and source of the transistor. V DS(act) Minimum required for transistors to enter the amplification region V DS (i.e., the threshold voltage at which the current effect begins to be significant). I D This is the leakage current.

[0025] In the empirical model of substrate current, the effect of temperature is mainly reflected in the coefficient. K 2. Research shows that, K 2 is a parameter positively correlated with temperature, and can usually be modeled as:

[0026]

[0027] in: Absolute temperature It is a positive coefficient.

[0028] because K 2. In the empirical model, on the negative exponent numerator, when temperature... When it rises, K Increasing the value of 2 leads to a decrease in the value of the exponent, thereby reducing the final substrate current. I DB Decrease.

[0029] This invention utilizes the above-described principle to measure temperature. For example... Figure 1 As shown, this embodiment of the invention provides a temperature sensor circuit that measures temperature by extracting the substrate voltage of an NMOS transistor in the temperature range to be measured and comparing it with a reference voltage corresponding to a predetermined temperature. Substrate voltage V B It is a quantity that is positively correlated with temperature. Figure 2 The substrate voltage is given. V B The relationship with temperature.

[0030] The circuit includes: a first NMOS transistor M1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, an operational amplifier OP, an analog-to-digital converter ADC, and a digital logic processing unit.

[0031] The gate of the first NMOS transistor M1 is connected to the first voltage VG1, the drain is connected to the power supply voltage VDD, and the source is grounded. The substrate is grounded through the first resistor R1 and simultaneously connected to the non-inverting input of the operational amplifier OP through the second resistor R2. The inverting input of the operational amplifier OP is connected to the reference voltage Vref through the third resistor R3. One end of the fourth resistor R4 is connected to the non-inverting input of the operational amplifier OP, and the other end is connected to the output of the operational amplifier OP. The output of the operational amplifier OP is then connected in sequence to the analog-to-digital converter (ADC) and the digital logic processing unit (DLU) before outputting.

[0032] Among them, the resistance values ​​of the second resistor R2 and the third resistor R3 are equal, according to Figure 1 It can be known that:

[0033]

[0034] in, The output voltage of the operational amplifier (OP). This is the substrate voltage of the first NMOS transistor M1. Based on the relationship between substrate voltage and temperature, the temperature of the region to be measured can be obtained.

[0035] Another embodiment of the invention, for example Figure 3 As shown, the circuit also includes a second NMOS transistor M2 and a fifth resistor R5. The gate of the second NMOS transistor M2 is connected to the second voltage VG2, the drain is connected to the power supply voltage VDD, the source is grounded, and the substrate is grounded through the fifth resistor R5. Simultaneously, the substrate serves as a reference voltage Vref, connected to the inverting input of the operational amplifier OP through the third resistor R3. The first NMOS transistor M1 is placed in the temperature region to be tested, and the second NMOS transistor M2 is placed in the constant-temperature region. Temperature measurement is performed by comparing the substrate voltage of the NMOS transistor in the temperature region to be tested with the substrate voltage of the NMOS transistor in the constant-temperature region.

[0036] The resistance of the first resistor R1 is equal to the resistance of the fifth resistor R5. The first voltage VG1 and the second voltage VG2 are equal.

[0037] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention.

Claims

1. A temperature sensor circuit, characterized in that, include: The system includes a first NMOS transistor M1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, an operational amplifier OP, an analog-to-digital converter ADC, and a digital logic processing unit. The gate of the first NMOS transistor M1 is connected to the first voltage VG1, the drain is connected to the power supply voltage VDD, the source is grounded, the substrate is grounded through the first resistor R1, and is connected to the positive input terminal of the operational amplifier OP through the second resistor R2. The inverting input of the operational amplifier OP is connected to the reference voltage Vref through the third resistor R3; The fourth resistor R4 is connected at one end to the positive input terminal of the operational amplifier OP and at the other end to the output terminal of the operational amplifier OP. The output of the operational amplifier OP is connected sequentially to both the analog-to-digital converter (ADC) and the digital logic processing unit before outputting. The resistance of the second resistor R2 is equal to the resistance of the third resistor R3; in, The output voltage of the operational amplifier (OP). The substrate voltage of the first NMOS transistor M1 is given; the temperature of the region to be measured is obtained based on the relationship between the substrate voltage and temperature.

2. The temperature sensor circuit according to claim 1, characterized in that, The reference voltage Vref is the voltage corresponding to a predetermined temperature.

3. The temperature sensor circuit according to claim 1, characterized in that, Also includes: The second NMOS transistor M2 and the fifth resistor R5; The gate of the second NMOS transistor M2 is connected to the second voltage VG2, the drain is connected to the power supply voltage VDD, the source is grounded, and the substrate is grounded through the fifth resistor R5. At the same time, the reference voltage Vref is connected to the inverting input terminal of the operational amplifier OP through the third resistor R3.

4. The temperature sensor circuit according to claim 3, characterized in that: The resistance value of the first resistor R1 is equal to the resistance value of the fifth resistor R5.

5. The temperature sensor circuit according to claim 3, characterized in that; The first NMOS transistor M1 is placed in the temperature region to be tested, and the second NMOS transistor M2 is placed in the constant temperature region.

6. The temperature sensor circuit according to claim 3, characterized in that; The first voltage VG1 and the second voltage VG2 are equal.

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