阅读说明：本技术 低功耗改进型带隙基准温度读出电路 (Low-power-consumption improved band-gap reference temperature reading circuit ) 是由 常玉春 刘钰皓 汪家奇 熊波涛 马艳华 申人升 刘炯晗 孙海荣 张璐 于 2021-07-26 设计创作，主要内容包括：本发明涉及传感器设计与应用技术领域,提供一种低功耗改进型带隙基准温度读出电路,包括彼此电连接的模数转换电路和带隙基准电路,所述带隙基准电路包括目标电压产生电路和运算放大器。所述目标电压产生电路包括：第一三极管、第二三极管、第三三极管、第四三极管、第一电阻器、第二电阻器、第三电阻器和第四电阻器。所述运算放大器的负极输入端连接有第一节点,正极输入端连接有第二节点,输出端连接有第四节点；第三电阻器和第四电阻器的上端都接有电源电压,下端分别连接到所述第一节点和第二节点。本发明能够提高温度读出的效率并降低功耗。(The invention relates to the technical field of sensor design and application, and provides a low-power-consumption improved band-gap reference temperature reading circuit which comprises an analog-digital conversion circuit and a band-gap reference circuit, wherein the analog-digital conversion circuit and the band-gap reference circuit are electrically connected with each other, and the band-gap reference circuit comprises a target voltage generation circuit and an operational amplifier. The target voltage generation circuit includes: the circuit comprises a first triode, a second triode, a third triode, a fourth triode, a first resistor, a second resistor, a third resistor and a fourth resistor. The negative input end of the operational amplifier is connected with a first node, the positive input end of the operational amplifier is connected with a second node, and the output end of the operational amplifier is connected with a fourth node; the third resistor and the fourth resistor are connected to a power supply voltage at the upper end and to the first node and the second node at the lower end, respectively. The invention can improve the efficiency of temperature reading and reduce the power consumption.)

1. A low-power consumption improved band gap reference temperature sensing circuit, comprising an analog-to-digital conversion circuit and a band gap reference circuit electrically connected to each other, the band gap reference circuit comprising a target voltage generation circuit and an operational amplifier (a 1);

the target voltage generation circuit includes: a first transistor (NPN1), a second transistor (NPN2), a third transistor (NPN3), a fourth transistor (NPN4), a first resistor (R1), a second resistor (R2), a third resistor (R3), and a fourth resistor (R4);

the negative electrode input end of the operational amplifier (A1) is connected with a first node (A), the positive electrode input end of the operational amplifier is connected with a second node (B), and the output end of the operational amplifier is connected with a fourth node (D); the upper ends of the third resistor (R3) and the fourth resistor (R4) are connected with a power supply Voltage (VDD), and the lower ends are respectively connected to the first node (A) and the second node (B);

the collectors of the first transistor (NPN1) and the second transistor (NPN2) are connected to the first node (a), and the collectors of the third transistor (NPN3) and the fourth transistor (NPN4) are connected to the second node (B); the bases of the second transistor (NPN2) and the third transistor (NPN3) are connected to the fourth node (D), the emitter of the second transistor (NPN2) is connected to the base of the fourth transistor (NPN4), and the emitter of the third transistor (NPN3) is connected to the base of the first transistor (NPN 1);

a third node (C) is connected to an emitter of the first triode (NPN1), one end of the first resistor (R1) is connected to an emitter of the fourth triode (NPN4), the other end is connected to the third node (C), one end of the second resistor (R2) is connected to the third node (C), and the other end is connected to Ground (GND).

2. The low power consumption improved bandgap reference temperature sensing circuit as recited in claim 1, wherein said analog to digital conversion circuit has a resolution of not less than 14 bits.

3. The low power consumption improved bandgap reference temperature sensing circuit according to claim 1, wherein said operational amplifier is a differential input single ended output operational amplifier.

4. The low power consumption improved bandgap reference temperature sensing circuit of claim 1, wherein said first transistor (NPN1), second transistor (NPN2), third transistor (NPN3) and fourth transistor (NPN4) are NPN transistors.

5. The low power consumption improved bandgap reference temperature sensing circuit according to claim 4, wherein the effective emitting area of the second transistor (NPN2) is m times that of the third transistor NPN3, and the effective emitting area of the fourth transistor (NPN4) is n times that of the first transistor (NPN1), wherein m and n are both greater than 1.

6. The low power consumption improved band gap reference temperature sensing circuit of claim 5, wherein m-8 and n-8.

Technical Field

The invention relates to the technical field of sensor design and application, in particular to a low-power-consumption improved band gap reference temperature reading circuit.

Background

Modern mobile equipment is developed day by day, and the requirement to all kinds of sensor power consumption is also stricter and stricter, and the temperature is as the most important physical parameter on mobile equipment, and low power consumption's temperature sensor also receives more and more favourably. For example, high-temperature early warning detection of a circuit board, battery over-temperature protection and spacecraft high-precision temperature detection are completed by matching with relatively low-power-consumption high-precision temperature sensors, most of the temperature sensors only generate analog signals related to temperature at the present stage, and therefore how to further reduce the overall power consumption on the basis of improving the precision and provide accurate and stable digital signal output related to the temperature is the future development direction.

The traditional temperature sensor only comprises a temperature sensing module and outputs an analog signal, so that the digital mobile device has difficulty in reading and processing the data signals, and the traditional temperature sensor is affected by matching errors between a process and a detection circuit and is difficult to ensure the accuracy of the temperature signals, so that how to realize the digital conversion of the temperature signals and reduce the external interference and the power consumption at the same time are problems to be solved urgently.

Disclosure of Invention

The invention mainly solves the technical problems of high power consumption and low efficiency of a temperature sensor in the prior art, and provides a low-power-consumption improved band gap reference temperature reading circuit to achieve the purposes of improving the temperature reading efficiency and reducing the power consumption.

The invention provides a low-power consumption improved band-gap reference temperature reading circuit, which abandons the traditional temperature sensing circuit, utilizes the improved band-gap reference circuit provided by the invention to sense the change of a temperature signal so as to generate a temperature-related voltage signal delta Vbe and a temperature-unrelated reference voltage VREF, wherein the temperature-related voltage signal delta Vbe enters an analog-to-digital conversion circuit for final digital quantization, and the temperature-unrelated reference voltage VREF provides a required bias voltage for the analog-to-digital conversion circuit. Because the structure omits a traditional temperature sensing module and integrates the temperature sensing function into a traditional band gap reference circuit, the improved band gap reference circuit provided by the invention is formed. The structure can improve the precision of the temperature sensor to a greater extent and reduce the overall power consumption at the same time. In addition, the problem that the temperature reading circuit structure is too complex can be solved, and the practicability of the circuit is greatly improved.

The application provides a low-power consumption improved band-gap reference temperature reading circuit, which comprises an analog-to-digital conversion circuit and a band-gap reference circuit which are electrically connected with each other, wherein the band-gap reference circuit comprises a target voltage generation circuit and an operational amplifier A1.

The target voltage generation circuit includes: a first transistor NPN1, a second transistor NPN2, a third transistor NPN3, a fourth transistor NPN4, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4.

The negative electrode input end of the operational amplifier A1 is connected with a first node A, the positive electrode input end is connected with a second node B, and the output end is connected with a fourth node D; the third resistor R3 and the fourth resistor R4 are both connected to the power supply voltage VDD at their upper ends and to the first node a and the second node B at their lower ends, respectively.

The collectors of the first and second transistors NPN1, NPN2 are connected to the first node a, and the collectors of the third and fourth transistors NPN3, NPN4 are connected to the second node B; bases of the second and third transistors NPN2 and NPN3 are connected to the fourth node D, an emitter of the second transistor NPN2 is connected to a base of the fourth transistor NPN4, and an emitter of the third transistor NPN3 is connected to a base of the first transistor NPN 1.

A third node C is connected to an emitter of the first triode NPN1, one end of the first resistor R1 is connected to the emitter of the fourth triode NPN4, the other end is connected to the third node C, one end of the second resistor R2 is connected to the third node C, and the other end is connected to the ground GND.

Furthermore, the resolution of the analog-to-digital conversion circuit is not lower than 14 bits.

Further, the operational amplifier is a differential input single-ended output operational amplifier.

Further, the first transistor NPN1, the second transistor NPN2, the third transistor NPN3, and the fourth transistor NPN4 are NPN transistors.

Further, the effective emitting area of the second transistor NPN2 is m times that of the third transistor NPN3, and the effective emitting area of the fourth transistor NPN4 is n times that of the first transistor NPN1, where m and n are both greater than 1.

Further, m is 8 and n is 8.

The temperature sensor can further reduce power consumption on the basis of improving the accuracy of the temperature sensor, and reduce the complexity of the whole structure. Compared with the prior art, the invention also has the following beneficial effects:

1. an independent temperature detection circuit module is abandoned, and the temperature detection function and the function of providing the reference voltage are integrated into a whole to form the improved band-gap reference circuit. The whole circuit is simplified and easy to integrate, and the whole power consumption is reduced.

2. The analog signal of the temperature is converted into a digital signal which is easy to process by a digital mobile device by utilizing the reading circuit, thereby expanding the application scene of the circuit.

Drawings

Fig. 1 is a schematic diagram of a prior art temperature sensing circuitry.

Fig. 2 is a structural diagram of a low power consumption improved bandgap reference temperature sensing circuit provided by the present invention.

Fig. 3 is a structural diagram of an improved bandgap reference circuit provided by the present invention.

Fig. 4 is a voltage transmission diagram of the improved bandgap reference circuit provided by the present invention.

Detailed Description

In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some but not all of the relevant aspects of the present invention are shown in the drawings.

The application provides a low-power consumption improved band-gap reference temperature reading circuit, which comprises an analog-to-digital conversion circuit and a band-gap reference circuit which are electrically connected with each other, wherein the band-gap reference circuit comprises a target voltage generation circuit and an operational amplifier A1.

The target voltage generation circuit includes: a first transistor NPN1, a second transistor NPN2, a third transistor NPN3, a fourth transistor NPN4, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4.

The negative electrode input end of the operational amplifier A1 is connected with a first node A, the positive electrode input end is connected with a second node B, and the output end is connected with a fourth node D; the third resistor R3 and the fourth resistor R4 are both connected to the power supply voltage VDD at their upper ends and to the first node a and the second node B at their lower ends, respectively.

The collectors of the first and second transistors NPN1, NPN2 are connected to the first node a, and the collectors of the third and fourth transistors NPN3, NPN4 are connected to the second node B; bases of the second and third transistors NPN2 and NPN3 are connected to the fourth node D, an emitter of the second transistor NPN2 is connected to a base of the fourth transistor NPN4, and an emitter of the third transistor NPN3 is connected to a base of the first transistor NPN 1.

A third node C is connected to an emitter of the first triode NPN1, one end of the first resistor R1 is connected to the emitter of the fourth triode NPN4, the other end is connected to the third node C, one end of the second resistor R2 is connected to the third node C, and the other end is connected to the ground GND.

Furthermore, the resolution of the analog-to-digital conversion circuit is not lower than 14 bits.

Further, the operational amplifier is a differential input single-ended output operational amplifier.

Further, the first transistor NPN1, the second transistor NPN2, the third transistor NPN3, and the fourth transistor NPN4 are NPN transistors.

Further, the effective emitting area of the second transistor NPN2 is m times that of the third transistor NPN3, and the effective emitting area of the fourth transistor NPN4 is n times that of the first transistor NPN1, where m and n are both greater than 1. In practical design, m is 8/1 and n is 16/2. Therefore, the positive and negative temperature coefficients can be well offset, R1 is too small, R2 is too large, and the difficulty of later-stage layout design is avoided.

The invention provides a low-power consumption improved band-gap reference temperature reading circuit, which introduces an analog-to-digital conversion circuit and an improved band-gap reference circuit on the basis of a traditional temperature sensor, and utilizes the temperature-sensitive characteristic of an NPN transistor to integrate the temperature detection function into the traditional band-gap reference circuit, so that the band-gap reference circuit not only detects a temperature signal, but also provides a temperature-independent reference voltage VREF for the analog-to-digital conversion circuit, and an independent temperature detection circuit module is abandoned, so that the temperature detection function and the function of providing the reference voltage are integrated. Therefore, the whole power consumption is reduced, and the improvement of the temperature detection precision is ensured while the circuit is simplified.

To achieve the above and other objects, the present invention provides an improved bandgap reference temperature sensing circuit with low power consumption, comprising: the design resolution of the analog-to-digital conversion circuit is not lower than 14bits so as to ensure the measurement precision of the whole temperature sensor; the improved band-gap reference circuit is used for ensuring that the improved band-gap reference circuit can provide voltage related to temperature under the condition of generating reference voltage; the aforementioned improved bandgap reference circuit comprises: the circuit comprises a target voltage generating circuit and a differential input single-ended output operational amplifier.

The temperature sensing circuit is implemented by 4 NPN transistors, and the voltage difference between the emitter and the base of the NPN transistors is linearly related to the temperature. Because the operational amplifier has a virtual break characteristic, namely the differential input single-ended output operational amplifier can realize that the voltages at two input ends are equal, two equal levels are provided for the improved band gap reference circuit, and therefore equal currents are generated for two branches. It is possible to generate a temperature-independent reference voltage VREF and a temperature-dependent voltage signal Δ Vbe for counteracting positive and negative temperature coefficients.

As shown in fig. 1, the prior art temperature sensing circuitry includes a conventional temperature sensing circuit, an analog-to-digital conversion circuit including a comparator, an amplifier, and a bandgap reference circuit, and a clock generation circuit. The conventional temperature sensing module sends a voltage signal related to temperature to the analog-to-digital conversion circuit, and the analog-to-digital conversion circuit sends a digital signal related to temperature. Fig. 2 is a structural diagram of a low-power consumption improved bandgap reference temperature sensing circuit system, which omits a conventional temperature detection circuit, and integrates the temperature detection function into a bandgap reference circuit, so as to form an improved bandgap reference circuit (as shown in fig. 3) provided by the present invention, the circuit generates a temperature-independent reference voltage VREF and provides the reference voltage VREF to an analog-to-digital conversion circuit for use as a bias voltage of the analog-to-digital conversion circuit, and the improved bandgap reference circuit also generates a temperature-dependent voltage signal Δ Vbe and provides the temperature-dependent voltage signal Δ Vbe to the analog-to-digital conversion circuit for processing, and finally the analog-to-digital conversion circuit generates a temperature-dependent digital signal, and a clock generation circuit is used for providing a clock signal to the analog-to-digital conversion circuit.

As shown in fig. 3, a schematic diagram of the improved bandgap reference circuit provided by the present invention includes a target voltage generating circuit and a differential input single-ended output operational amplifier a 1. The target voltage generating circuit generates a temperature-independent reference voltage VREF and a temperature-dependent voltage signal DeltaVbe, and the temperature-dependent voltage signal DeltaVbe is a positive temperature coefficient voltage. The target voltage generating circuit includes a first transistor NPN1, a second transistor NPN2, a third transistor NPN3, a fourth transistor NPN4, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4.

The effective emitter area of the second transistor NPN2 is m times the effective emitter area of the third transistor NPN3 and the effective emitter area of the fourth transistor NPN4 is n times the effective emitter area of the first transistor NPN 1. Preferably, m and n may be 8. A collector of the first transistor NPN1, the second transistor NPN2 is connected to a lower end of the third resistor R3, i.e., node a, and a collector of the third transistor NPN3, the fourth transistor NPN4 is connected to a lower end of the fourth resistor R4, i.e., node B. The upper ends of the third resistor R3 and the fourth resistor R4 are connected with the power voltage VDD. The bases of the second and third transistors NPN2, NPN3 are connected to node D. The emitter of the third transistor NPN3 is connected to the base of the first transistor NPN 1. An emitter of the second transistor NPN2 is connected to a base of the fourth transistor NPN4, an emitter of the fourth transistor NPN4 is connected to an upper end of the first resistor R1, and a lower end of the first resistor R1 and an emitter of the first transistor NPN1 are connected to an upper end of the second resistor R2, i.e., a node C. The positive and negative input ends of the differential input single-ended output operational amplifier A1 are connected to the node B and the node A respectively. The output of the differential input single-ended output operational amplifier a1 is connected to node D. The circuit generates a temperature-independent reference voltage VREF at node D and a temperature-dependent voltage signal Δ Vbe at node C.

The working principle of the circuit is as follows: since the two input terminals of the differential input single-ended output operational amplifier a1 have a terminal virtual-break characteristic, that is, the potentials at the points a and B are equal, when the resistance values of the resistor R3 and the resistor R4 are equal, the current I1 is equal to I2. The basic principle of the triode shows that the emitter current is equal to beta times of the base current (beta is the amplification factor of the common-emitter direct current). Let the emitter currents of the first and fourth transistors NPN1, NPN4 be I3 and I4, respectively. Then:

wherein beta is a co-injection direct current amplification factor, and according to KCL law (kirchhoff current law), I1 is I5+ I6, and I2 is I7+ I8.

Current I1 ═ I2 according to the preamble. Thus, it is possible to obtain:

therefore, I3 ═ I4 can be obtained. (the input and output ends of the differential input single-ended output operational amplifier a1 have their dc common mode levels, so that the NPN triodes NPN1, NPN2, NPN3 and NPN4 can be ensured to be in the amplification region, so that I3 ═ I4 ≠ 0.) the NPN triode base emitter voltage Vbe has a negative temperature coefficient. The voltage across resistor R1 can thus be found to be:

VBE1, VBE2, VBE3 and VBE4 are NPN type triodes NPN1, NPN2, NPN3 and NPN4 base emitter voltages respectively. VT is the threshold voltage and VT ═ kT/q, with a positive temperature coefficient.

Wherein: t is the absolute temperature, k is the Boltzmann (Boltzmann) constant, and q is the charge on the electron. The voltage VREF at node D is thus obtained as:

VT has a positive temperature coefficient, VBE1 and VBE3 have a negative temperature coefficient, and therefore it can be achieved that the voltage VREF is equal to the band gap voltage of the semiconductor material (silicon) by adjusting the resistance values of the resistor R1 and the resistor R2, and the voltage VREF is a bias voltage having very low temperature sensitivity. The voltage Δ Vbe at node C is:

VT has a positive temperature coefficient, so the voltage avbe at node C has a positive temperature coefficient, which can be used as a temperature-dependent voltage signal.

The invention provides a low-power consumption improved band-gap reference temperature reading circuit system structure, which mainly comprises an improved band-gap reference circuit, an analog-to-digital conversion circuit and a clock generation circuit, wherein the working principle of each module is as follows:

the working principle of the improved band-gap reference circuit is as follows: when the temperature of the environment in the circuit system changes, the improved band-gap reference circuit generates two voltage values, one is a temperature-dependent voltage signal delta Vbe, and the other is a temperature-independent reference voltage VREF, and the two voltage values are applied to a temperature signal input end and a bias voltage input end of the analog-to-digital conversion circuit.

The working principle of the clock generation circuit is as follows: when the improved band gap reference circuit works, the clock generating circuit generates a clock signal required by an analog-to-digital conversion circuit.

The working principle of the analog-to-digital conversion circuit is shown in fig. 4, and specifically includes: the analog-to-digital conversion circuit receives a temperature-dependent voltage signal Δ Vbe from the modified bandgap reference circuit as an input voltage signal. And simultaneously, calculating to generate a digital signal related to the temperature.

Here, BGR (band gap reference) is usedCircuit) module uses 4 NPN triodes, because the negative temperature coefficient can be improved from Vbe to 2Vbe, and the effective emitting area of four NPN triodes is also n times and m times, the four NPN structure can also increase positive temperature coefficient toHigh positive and negative temperature coefficients can improve the stability of output VREF. The two NPN are also part of the BGR module and are not temperature sensing transistors in the conventional sense. The current patents and articles in the prior art do not use the BGR module to detect the temperature signal, because the positive and negative temperature signals in the BGR module need to cancel each other to generate VREF, and because they cancel, they are different from the temperature detection in the prior art patents and articles. Since the ADC in the sensing circuit requires the reference voltage VREF. VREF is from BGR, so BGR is indispensable, and the band gap reference circuit is used for generating a temperature signal on the basis of band gap reference, so that the power consumption can be reduced on the basis of not introducing other temperature sensing circuits.

A bandgap reference circuit (BGR) provides a bias voltage VREF and a temperature signal Δ Vbe to an analog-to-digital conversion circuit (ADC). VREF may be provided to the ADC only through an LDO (low dropout linear regulator) circuit, but this is passed through the LDO module for better performance, and here the LDO module is not added for simplicity, without affecting the novelty and inventive aspects of the present application.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: modifications of the technical solutions described in the embodiments or equivalent replacements of some or all technical features may be made without departing from the scope of the technical solutions of the embodiments of the present invention.