Simple circuit capable of generating negative precision voltage reference and resisting high temperature of 200 DEG C

Abstract

The utility model belongs to the technical field of electronic circuits, and discloses a simple circuit capable of generating negative precision voltage reference and resisting high temperature of 200 DEG C. The simple circuit comprises a positive reference voltage source U1, a capacitor C1 and an operational amplifier U2, the output end of the positive reference voltage source U1 is connected to the inverted input end of the operational amplifier U2 through the isolation resistor R, the input end of the positive reference voltage source U1 is connected to a VCC power supply, and the GND pin of the positive reference voltage source U1 is connected to the output end of the operational amplifier U2; a pin 3 of the positive reference voltage source U1 is connected to a VCC power supply; a pin 3 of the positive input end of the operational amplifier U2 is grounded, and a pin 2 of the operational amplifier U2 is connected with a negative power supply; the two ends of the capacitor C1 are connected with the floating ground end of the positive reference voltage source U1 and the output end of the positive reference voltage source U1. According to the utility model, fewer components are used, and the precision is higher; the circuit has flexibility, and different negative precision voltage references can be generated by selecting different reference voltage sources and amplifier combinations; and the negative voltage reference generated by the module at the high temperature of 200 DEG C still has very good temperature stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic circuit, more particularly, to a simple circuit for generating negative precision voltage reference and resistant to 200℃ high temperature. BACKGROUND

[0002] In industrial automation control system, stable negative voltage reference plays an indispensable role in maintaining system stable operation. For example, in motor speed regulation system, in order to realize accurate control of motor speed, the actual speed of the motor is compared with the set speed through feedback control circuit, and the input voltage of the motor is adjusted according to the deviation. The negative voltage reference circuit provides stable reference voltage for the feedback control circuit, so that the controller can accurately calculate the deviation and output correct control signal. If the negative voltage reference is unstable, it will lead to the controller receiving incorrect feedback signal, and then the motor speed fluctuation, affecting the quality of products on the production line. In some highly automated production process, such as photolithography process in semiconductor chip manufacturing, stable negative voltage reference is a key factor to ensure the accurate operation of the equipment and realize nanometer level precision control, which is directly related to the yield and production efficiency of products.

[0003] The prior art document with publication number CN101930248B provides a kind of adjustable negative voltage reference circuit, including a positive temperature coefficient constant current source, a negative temperature coefficient constant current source, an adjustable output resistance;The positive temperature coefficient constant current source is connected with the negative temperature coefficient constant current source in parallel, downwardly connects negative power supply, upwardly connects one end of adjustable output resistance and serves as negative voltage reference output end, and the other end of adjustable output resistance is connected with ground;Different temperature coefficient constant current sources are added in a certain proportion to form a constant output current source only related to resistance temperature coefficient, and adjustable negative voltage reference is generated through the adjustable output resistance.Invention can realize continuous adjustable zero temperature drift negative voltage reference source, and is suitable for bipolar transistor and metal oxide field effect transistor compatible process implementation.

[0004] The prior art scheme in the above has the following defects although the related beneficial effects can be realized by the structure of prior art: in modern electronic equipment, especially in application occasions requiring accurate measurement and control, a stable and high-precision negative voltage reference circuit is crucial. In data acquisition system, deriving reference from noisy system power supply can introduce significant error.

[0005] In view of this, we propose a simple circuit for generating negative precision voltage reference and resistant to 200℃ high temperature. SUMMARY

[0006] 1. Technical problem to be solved

[0007] The purpose of the present application is to provide a simple circuit for generating a negative precision voltage reference and resistant to 200℃ high temperature, which solves the technical problems proposed in the background art, realizes less use of components and higher precision; the circuit has flexibility, and different negative precision voltage references can be generated by selecting different reference voltage sources and amplifiers; the thick film gold wire pressure welding process is adopted, so that the negative voltage reference generated by the module still has very good temperature stability at 200℃ high temperature.

[0008] 2. Technical solution

[0009] The technical solution of the present application provides a simple circuit for generating a negative precision voltage reference and resistant to 200℃ high temperature, which includes a positive reference voltage source U1, a capacitor C1 and an operational amplifier U2.

[0010] The core part of the circuit is to convert the positive reference voltage (generated by the positive reference voltage source U1) into a negative reference voltage through the operational amplifier U2.

[0011] The positive reference voltage source U1 is a high-precision serial positive reference voltage source; the positive reference voltage source U1 uses internal precision voltage reference elements (such as bandgap reference) and high-precision digital-to-analog conversion circuit to convert the input power supply voltage into stable and accurate positive reference voltage output. Its serial interface can conveniently communicate with microcontrollers or other digital circuits, and the output voltage can be adjusted and calibrated through digital signals, thereby further improving the precision and stability of the output voltage.

[0012] The operational amplifier U2 adopts a low-noise low-offset operational amplifier. The operational amplifier U2 stabilizes the output voltage at a precise negative reference voltage value through negative feedback. Due to its low noise and low offset characteristics, it can effectively reduce noise interference and offset errors in the input signal, thereby improving the precision of the output negative reference voltage.

[0013] The output end (6-pin Vout) of the positive reference voltage source U1 is connected to the inverting input end (4-pin) of the operational amplifier U2 through an isolation resistor R. The positive reference voltage source U1 is floating (4-pin), its input (2-pin Vin) is connected to the VCC power supply, and the GND pin (4-pin) of the positive reference voltage source U1 is connected to the output of the operational amplifier U2 (i.e. negative precision reference voltage -VREF).

[0014] In order to ensure continuous output of the circuit, the 3-pin of the positive reference voltage source U1 is connected to the VCC power supply. In addition, the positive input end (3-pin) of the operational amplifier U2 is grounded, and the 2-pin of the operational amplifier U2 is connected to the negative power supply.

[0015] Capacitor C1 is connected with the floating ground end (4 feet) of the positive reference voltage source U1 and the output end (6 feet Vout) of the positive reference voltage source U1 respectively, and functions as isolating and decoupling the reference voltage source between the input and output of the operational amplifier U2. The main function of the capacitor C1 is to isolate and decouple the reference voltage source between the input and output of the operational amplifier U2. In the actual circuit operation process, the output signal of the positive reference voltage source U1 is easily affected by various interference factors, such as power supply noise, electromagnetic interference, etc. The capacitor C1 can provide a low-impedance path for these interference signals, so that they are bypassed to the ground through the capacitor C1, thereby effectively reducing the interference of the interference signals on the input signal of the operational amplifier U2, and ensuring that the operational amplifier U2 can receive a pure and stable input signal.

[0016] As an optional scheme of the utility model, a decoupling capacitor C2 is connected at the VCC end of the positive reference voltage source U1. The function is to decouple the VCC power supply. Various noises and ripples often exist in the power supply, which will have a negative impact on the working stability of the positive reference voltage source U1. The capacitor C2 can provide a low-impedance path for these noises and ripples, so that they are bypassed to the ground through the capacitor C2, thereby ensuring that the positive reference voltage source U1 can obtain a clean and stable power supply.

[0017] As an optional scheme of the utility model, a decoupling capacitor C3 is connected at the VCC end of the operational amplifier U2. The main function is to decouple the positive power supply of the operational amplifier U2. Through the decoupling function of the capacitor C3, the interference of the power supply noise on the performance of the operational amplifier U2 can be effectively reduced, and the working stability of the operational amplifier U2 can be improved.

[0018] As an optional scheme of the utility model, a decoupling capacitor C4 is connected at the VEE end of the operational amplifier U2. The function is to decouple the negative power supply of the operational amplifier U2. The noise and ripple in the negative power supply will also affect the performance of the operational amplifier U2, and the capacitor C4 can effectively filter out these noises and ripples, ensuring that the operational amplifier U2 can work stably under the negative power supply.

[0019] As an optional scheme of the utility model, the simple circuit for generating a negative precision voltage reference and resistant to 200 DEG C high temperature adopts a thick film gold wire pressure welding process, so that the negative voltage reference generated by the module under 200 DEG C high temperature still has very good temperature stability.

[0020] Further, gold wire is used as the connecting medium, and the gold wire and the thick film conductor are firmly connected through a special pressure welding process. This connection method can withstand the thermal stress caused by high temperature and reduce the phenomenon of poor contact caused by temperature changes. Compared with the traditional welding method, the connection point formed by thick film gold wire pressure welding has higher mechanical strength and better electrical connection performance. In a high temperature environment, the connection point will not loosen or break, ensuring stable connection between each component in the circuit and effectively avoiding signal interruption or interference caused by unstable connection.

[0021] 3. Beneficial effects

[0022] One or more technical solutions provided in the technical scheme of the present application have at least the following technical effects or advantages:

[0023] 1. Fewer components are used and higher precision is achieved.

[0024] 2. The circuit has flexibility: different negative precision voltage references can be generated by selecting different reference voltage sources and amplifiers.

[0025] 3. The thick film gold wire pressure welding process makes the negative voltage reference generated by the module at 200°C high temperature still have very good temperature stability.

[0026] 4. High-precision voltage output: the positive reference voltage source U1 uses an internal precision voltage reference element and a high-precision digital-to-analog conversion circuit to convert the input power supply voltage into a stable and accurate positive reference voltage output. The output voltage precision and stability are improved. The operational amplifier U2 uses a low-noise low-offset operational amplifier, which can effectively reduce noise interference and offset errors in the input signal, accurately convert the positive reference voltage to an accurate negative reference voltage output, and meet the application scenarios with extremely high voltage precision requirements.

[0027] 5. Good anti-interference performance: the capacitor C1 is connected to the floating ground terminal and the output terminal of the positive reference voltage source U1, respectively, which can effectively isolate and decouple the reference voltage source between the input and output of the operational amplifier U2, reduce the interference of power supply noise, electromagnetic interference, etc. on the input signal of the operational amplifier U2, and ensure that it receives pure and stable input signals. The decoupling capacitor C2 connected to the VCC terminal of the positive reference voltage source U1, and the decoupling capacitors C3 and C4 connected to the VCC terminal and the VEE terminal of the operational amplifier U2, respectively, can provide a low-impedance path for noise and ripple in the power supply, bypassing to ground, ensuring that the positive reference voltage source U1 and the operational amplifier U2 obtain clean and stable power supply, and improving the overall anti-interference ability of the circuit. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The figure is a schematic diagram of the simple circuit disclosed in the present application for generating a negative precision voltage reference and resisting 200°C high temperature. DETAILED DESCRIPTION

[0029] The application is further described in detail below with reference to the accompanying drawings.

[0030] Reference Figure 1 The embodiment of the application provides a simple circuit for generating a negative precision voltage reference and resisting 200 DEG C high temperature, which comprises a positive reference voltage source U1, a capacitor C1 and an operational amplifier U2.

[0031] The core part of the circuit is to convert the positive reference voltage (generated by the positive reference voltage source U1) into a negative reference voltage through the operational amplifier U2.

[0032] The positive reference voltage source U1 is a high-precision serial positive reference voltage source; the positive reference voltage source U1 utilizes an internal precision voltage reference element (such as a band gap reference) and a high-precision digital-to-analog conversion circuit to convert an input power supply voltage into a stable and accurate positive reference voltage output. The serial interface of the positive reference voltage source U1 can conveniently communicate with a microcontroller or other digital circuits, and the output voltage is adjusted and calibrated through a digital signal, so that the precision and stability of the output voltage are further improved. Due to the adoption of an advanced semiconductor process and circuit design, the positive reference voltage source U1 has an extremely low temperature coefficient, and can maintain the stability of the output voltage in a wide temperature range. For example, in the temperature range of-40 DEG C to 200 DEG C, the change rate of the output voltage is less than ±0.01% / C. Meanwhile, the positive reference voltage source U1 also has the characteristics of high output impedance and low noise, and can provide a clean and stable input signal for the subsequent operational amplifier. The positive reference voltage source U1 has the characteristic of high output impedance, so that it can excellently maintain the stability of the output voltage under different load conditions. When the load changes, the high output impedance can significantly reduce the interference of the load current on the output voltage, and ensure the accuracy of the output voltage. Meanwhile, the low noise characteristic is also a key factor for ensuring that the subsequent operational amplifier can receive a pure and stable input signal. Noise mainly comes from thermal noise, shot noise and the like of semiconductor devices, and the positive reference voltage source U1 greatly reduces the noise components in the output signal through various means such as optimization of circuit layout, selection of low-noise semiconductor devices and adoption of advanced filtering technology, and provides a high-quality input signal for the entire circuit.

[0033] The output end (6-pin Vout) of the positive reference voltage source U1 is connected to the inverting input end (4-pin) of the operational amplifier U2 through an isolation resistor R. The positive reference voltage source U1 is floating (4-pin), the input (2-pin Vin) of the positive reference voltage source U1 is connected to a VCC power supply, and the GND pin (4-pin) of the positive reference voltage source U1 is connected to the output of the operational amplifier U2 (that is, a negative precision reference voltage-VREF).

[0034] To ensure the continuous output of the circuit, the 3-pin of the positive reference voltage source U1 is connected to the VCC power supply. In addition, the positive input terminal (3-pin) of the operational amplifier U2 is grounded, and the 2-pin of the operational amplifier U2 is connected to the negative power supply.

[0035] The operational amplifier U2 works based on the differential amplification principle. When the positive reference voltage generated by the positive reference voltage source U1 is input to the inverting input terminal (4-pin) of the operational amplifier U2, and the positive input terminal (3-pin) is grounded as the reference potential, the differential pair inside the operational amplifier starts to work. The differential pair is usually composed of two transistors with high matching characteristics, which have high sensitivity to the difference of the input signal and can amplify extremely small difference signals into output signals with larger amplitude. This differential amplification method can effectively suppress the interference of common-mode signals and improve the anti-interference ability of the circuit.

[0036] The capacitor C1 is connected between the floating ground terminal (4-pin) of the positive reference voltage source U1 and the output terminal (6-pin Vout) of the positive reference voltage source U1, which plays a role in isolating and decoupling the reference voltage source between the input and output of the operational amplifier U2. The main function of the capacitor C1 is to isolate and decouple the reference voltage source between the input and output of the operational amplifier U2. In actual circuit operation, the output signal of the positive reference voltage source U1 is easily affected by various interference factors, such as power supply noise, electromagnetic interference, etc. The capacitor C1 can provide a low-impedance path for these interference signals, allowing them to bypass to ground through the capacitor C1, thereby effectively reducing the interference of the interference signals on the input signal of the operational amplifier U2, ensuring that the operational amplifier U2 can receive pure and stable input signals. The selection of the capacitance value of the capacitor C1 needs to consider factors such as the working frequency of the circuit. For high-frequency interference signals, the capacitor C1 should have a low equivalent series resistance (ESR) and equivalent series inductance (ESL) to ensure that it can effectively filter out high-frequency interference. Generally, the capacitance value of the capacitor C1 can be selected between several pico-farads and several tens of micro-farads, and the specific value needs to be optimized according to the working frequency and interference of the actual circuit.

[0037] Low noise performance guarantee: The low noise characteristic of the operational amplifier U2 is one of its important advantages, which can effectively reduce the noise interference in the input signal. Noise mainly comes from the transistors, resistors and other devices inside the operational amplifier. In order to reduce the noise level, the operational amplifier U2 adopts low-noise transistors in the design process, optimizes the circuit layout to reduce interference in the signal transmission process, and adopts advanced filtering technology to filter the input and output signals. These measures work together to control the noise level within a very low range, ensuring that the output negative reference voltage is pure and meets the demanding requirements of signal quality.

[0038] Further, a decoupling capacitor C2 is connected to the VCC terminal of the positive reference voltage source U1; its role is to decouple the VCC power supply. Various noise and ripple often exist in the power supply, which will have a negative impact on the working stability of the positive reference voltage source U1. Capacitor C2 can provide a low-impedance path for these noise and ripple, bypassing them to ground through capacitor C2, thereby ensuring that the positive reference voltage source U1 can obtain clean and stable power supply. The capacitance of capacitor C2 is generally large, usually between a few microfarads and a few tens of microfarads, to meet the effective filtering requirements of power supply noise and ripple.

[0039] Further, a decoupling capacitor C3 is connected to the VCC terminal of the operational amplifier U2; mainly to decouple the positive power supply of the operational amplifier U2. Through the decoupling effect of capacitor C3, the interference of power supply noise on the performance of the operational amplifier U2 can be effectively reduced, and the working stability of the operational amplifier U2 can be improved. The selection of the capacitance of capacitor C3 also needs to consider the power supply characteristics of the operational amplifier U2 and the working frequency of the circuit, and is generally between a few microfarads and a few tens of microfarads, to ensure good suppression effect on the noise and ripple of the positive power supply.

[0040] Further, a decoupling capacitor C4 is connected to the VEE terminal of the operational amplifier U2. Its role is to decouple the negative power supply of the operational amplifier U2. The noise and ripple in the negative power supply will also affect the performance of the operational amplifier U2, and capacitor C4 can effectively filter out these noise and ripple to ensure that the operational amplifier U2 can work stably under negative power supply. The selection of the capacitance of capacitor C4 is similar to that of capacitor C3, and is generally also between a few microfarads and a few tens of microfarads, to meet the decoupling requirements of the negative power supply.

[0041] Further, the simple circuit for generating a negative precision voltage reference and resistant to 200℃ high temperature adopts a thick film gold wire pressure welding process, so that the negative voltage reference generated by the module still has very good temperature stability at 200℃ high temperature. In a high temperature environment, ordinary circuit connection methods are prone to many problems, while the thick film gold wire pressure welding process can effectively cope with it. The thick film conductor material used in thick film technology has good high temperature resistance. In a 200℃ high temperature environment, the thick film conductor can maintain stable electrical performance and will not change significantly in resistance due to high temperature, thereby ensuring the stability of signal transmission in the circuit. The thick film conductor needs to have excellent high temperature resistance to ensure stable operation of the circuit in a high temperature environment.

[0042] Further, gold wire is used as the connecting medium, and the gold wire and the thick film conductor are firmly connected through a special pressure welding process. This connection mode can withstand thermal stress caused by high temperature and reduce the phenomenon of poor contact caused by temperature change. Compared with the traditional welding mode, the connection point formed by thick film gold wire pressure welding has higher mechanical strength and better electrical connection performance. In a high temperature environment, the connection point will not have problems such as loosening and breaking, ensuring the stable connection between each component in the circuit and effectively avoiding signal interruption or interference caused by unstable connection.

[0043] The application uses fewer components and has higher precision; the circuit has flexibility. Different negative precision voltage references can be generated by selecting different reference voltage sources and amplifier combinations; the thick film gold wire pressure welding process makes the negative voltage reference generated by the module have very good temperature stability at 200 DEG C high temperature; the thick film gold wire pressure welding process greatly reduces the size of the module.

[0044] The above-described embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A simple circuit for generating a negative precision voltage reference and withstanding temperatures up to 200°C, comprising: A positive reference voltage source U1, a capacitor C1, and an operational amplifier U2; characterized in that: The output pin 6 of the positive reference voltage source U1 is connected to the inverting input pin 4 of the operational amplifier U2 through the isolation resistor R. Pin 4 of the positive reference voltage source U1 is floating ground. The input pin 2 Vin of the positive reference voltage source U1 is connected to the VCC power supply, and the GND pin 4 of the positive reference voltage source U1 is connected to the output VREF of the operational amplifier U2. To ensure continuous output from the circuit, pin 3 of the positive reference voltage source U1 is connected to the VCC power supply; pin 3 of the positive input terminal of the operational amplifier U2 is grounded, and pin 2 of the operational amplifier U2 is connected to the negative power supply. The two ends of capacitor C1 are connected to the floating ground pin 4 of positive reference voltage source U1 and the output pin 6 Vout of positive reference voltage source U1, respectively, which serves to isolate and decouple the reference voltage source between the input and output of operational amplifier U2.

2. The simple circuit for generating a negative precision voltage reference and withstanding a high temperature of 200°C according to claim 1, characterized in that: The positive reference voltage source U1 is a high-precision serial positive reference voltage source; the operational amplifier U2 is a low-noise, low-offset operational amplifier.

3. The simple circuit for generating a negative precision voltage reference and withstanding a high temperature of 200°C according to claim 1, characterized in that: A decoupling capacitor C2 is connected to the VCC terminal of the positive reference voltage source U1; Its function is to decouple the VCC power supply.

4. The simple circuit for generating a negative precision voltage reference and withstanding a high temperature of 200°C according to claim 1, characterized in that: A decoupling capacitor C3 is connected to the VCC terminal of operational amplifier U2 to decouple the positive power supply of operational amplifier U2, reduce the interference of power supply noise on the performance of operational amplifier U2, and improve the working stability of operational amplifier U2.

5. The simple circuit for generating a negative precision voltage reference and withstanding a high temperature of 200°C according to claim 1, characterized in that: A decoupling capacitor C4 is connected to the VEE terminal of operational amplifier U2 to decouple the negative power supply of operational amplifier U2.

6. The simple circuit for generating a negative precision voltage reference and withstanding a high temperature of 200°C according to claim 1, characterized in that: The use of thick-film gold wire bonding technology ensures that the negative voltage reference generated by the module still has very good temperature stability at a high temperature of 200℃.

7. The simple circuit for generating a negative precision voltage reference and withstanding a high temperature of 200°C according to claim 6, characterized in that: Gold wire is used as the connecting medium, and a strong connection is achieved between the gold wire and the thick film conductor through a pressure welding process.

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