CN201156720Y - Circuit of voltage follower - Google Patents
Circuit of voltage follower Download PDFInfo
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- CN201156720Y CN201156720Y CNU2007200080374U CN200720008037U CN201156720Y CN 201156720 Y CN201156720 Y CN 201156720Y CN U2007200080374 U CNU2007200080374 U CN U2007200080374U CN 200720008037 U CN200720008037 U CN 200720008037U CN 201156720 Y CN201156720 Y CN 201156720Y
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- operational amplifier
- voltage follower
- circuit
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- voltage
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Abstract
The utility model relates to a voltage follower circuit, which consists of two operational amplification circuits with consistent parameters, two resistances R1 and R2. The circuit realizes the low-deviation following of the output voltage Vout to the input voltage Vin; and the temperature exerts little influence. In the voltage follower circuit, the ordinary adjustable resistance in the DA output circuit is eliminated; and the actual production and manufacture efficiency is improved. The voltage follower circuit has the advantages of low deviation, low temperature drift and low costs. Moreover, the voltage follower circuit can be easily connected in the feedback element to further improve the accuracy.
Description
Technical field
The utility model relates to a kind of voltage follower circuit.
Background technology
Voltage follower circuit is circuit design field a kind of circuit function module very commonly used, has analog circuit that voltage follower is just arranged basically, because it can finish function that is in daily use in the circuit design---and impedance conversion or impedance are isolated.All there is following problem usually in existing low-cost voltage follower circuit: though one, output voltage can follow input voltage and change, and has a bigger difference (high deviation) usually; Two, the deviation between output voltage and the input voltage can change with variation of temperature (high temperature floats).Because voltage follower circuit is the element circuit that is in daily use, so expensive voltage follower circuit is difficult to be applied in the product widely.
The utility model content
At above-mentioned prior art, the purpose of this utility model provides a kind of voltage follower circuit, and low deviation, low temperature float, low cost, improves the efficient that actual production is made, and can insert feedback element at an easy rate and further improve precision.
For achieving the above object, the voltage follower circuit that the utility model provides is by the operational amplifier of two parameter unanimities, form with resistance R 1 and R2, wherein the electrode input end of operational amplifier U1A meets the output voltage V out of voltage follower, the negative input of operational amplifier U1A and the resistance R of series connection 1 are with after resistance R 2 is connected, receive the negative input of operational amplifier U1B, and the output of operational amplifier U1A is connected with resistance R 2 with resistance R 1; The output voltage V out of the output termination voltage follower of operational amplifier U1B, the electrode input end of operational amplifier U1B connects the input voltage vin of voltage follower.
Operational amplifier U1A and operational amplifier U1B are two operational amplifiers that parameter is consistent on the same Chip Packaging, and then the input voltage deviation of two operational amplifiers equates, i.e. Vin-Ua=Vout-Ub; The input bias current of two operational amplifiers also equates Ib1=Ib2.Select R1=R2 then:
Ua＝Uc+Ib2×R2＝Uc+Ib1×R1＝Ub
Thereby Vin=Vout.Because also set up when the pass of Vin-Ua=Vout-Ub and Ib1=Ib2 ties up to variations in temperature, so Vin=Vout also sets up when variations in temperature.R1 and R2 have certain deviation in side circuit, but still have Ua-Ib2 * R2=Uc=Ub-Ib1 * R1, be Ua-Ub=Ib2*R2-Ib1*R1 ≈ Ib1* (R2-R1), modern integrated operational amplifier input bias current Ib is generally tens nA, when R1, R2 select for use the precision of 10K to be ± 1% resistance, several only uV of Vin-Vout=Ua-Ub, the Ib of modern operational amplifier is typically 10pA/ ℃ with variation of temperature, and Vin-Vout is with 2nV/ ℃ only of variation of temperature.In sum, this circuit has realized that output voltage V out follows the low deviation of input voltage vin, and changes with variation of temperature hardly.
In actual use, avoid occurring the high-frequency self-excitation vibration, should add the high frequency negative feedback network usually, between the positive output end of capacitor C 1 access operational amplifier U1A and the inverting input of operational amplifier U1B for steady operation.When the current driving ability of exporting is not enough, add the driving intensifier circuit, the output of operational amplifier inserts the base stage of triode Q1.
Basic circuit principle of the present utility model is as shown in Figure 1: Vin is the input voltage of voltage follower among the figure, and Vout is the output voltage of voltage follower.Amplifier U1A and amplifier U1B are two amplifiers that parameter is consistent on the same Chip Packaging, and then the input voltage deviation of two amplifiers equates, i.e. Vin-Ua=Vout-Ub; The input bias current of two amplifiers also equates Ib1=Ib2.Select R1=R2 then:
Ua＝Uc+Ib2×R2＝Uc+Ib1×R1＝Ub
Thereby Vin=Vout.When tying up to variations in temperature, the pass of Vin-Ua=Vout-Ub and Ib1=Ib2 also sets up, so Vin=Vout also sets up when variations in temperature.R1 and R2 have certain deviation in side circuit,
But still have Ua-Ib2 * R2=Uc=Ub-Ib1 * R1, be Ua-Ub=Ib2*R2-Ib1*R1 ≈ Ib1* (R2-R1), modern integrated transporting discharging input bias current Ib is generally tens nA, when R1, R2 select for use the precision of 10K to be ± 1% resistance, several only uV of Vin-Vout=Ua-Ub, the Ib of modern amplifier is typically 10pA/ ℃ with variation of temperature, and Vin-Vout is with 2nV/ ℃ only of variation of temperature.In sum, this circuit has realized that output voltage V out follows the low deviation of input voltage vin, and changes with variation of temperature hardly.
In actual use, avoid occurring the high-frequency self-excitation vibration, should add the high frequency negative feedback network usually, as the capacitor C in the accompanying drawing 21 for steady operation.
If the current driving ability of output can not add the driving intensifier circuit completely during actual the use, as the triode Q1 in the accompanying drawing 3.
The utility model provides described voltage follower circuit, has removed adjustable resistance commonly used in the DA output circuit, improves the efficient that actual production is made, and low deviation, low temperature float, low cost, and can insert feedback element at an easy rate and further improve precision.This circuit can be used in actual product very soon.
Description of drawings
Fig. 1 is the circuit block diagram of the utility model embodiment 1;
Fig. 2 is the circuit block diagram of the utility model embodiment 2;
Fig. 3 is the circuit block diagram of the utility model embodiment 3.
Embodiment
Embodiment 1:
Present embodiment is as shown in Figure 1: Vin is the input voltage of voltage follower, and Vout is the output voltage of voltage follower.Amplifier U1A and amplifier U1B are two amplifiers that parameter is consistent on the same Chip Packaging, and then the input voltage deviation of two amplifiers equates, i.e. Vin-Ua=Vout-Ub; The input bias current of two amplifiers also equates Ib1=Ib2.Select R1=R2 then:
Ua＝Uc+Ib2×R2＝Uc+Ib1×R1＝Ub
Thereby Vin=Vout.When tying up to variations in temperature, the pass of Vin-Ua=Vout-Ub and Ib1=Ib2 also sets up, so Vin=Vout also sets up when variations in temperature.R1 and R2 have certain deviation in side circuit, but still have Ua-Ib2 * R2=Uc=Ub-Ib1 * R1, be Ua-Ub=Ib2*R2-Ib1*R1 ≈ Ib1* (R2-R1), modern integrated transporting discharging input bias current Ib is generally tens nA, when R1, R2 select for use the precision of 10K to be ± 1% resistance, several only uV of Vin-Vout=Ua-Ub, the Ib of modern amplifier is typically 10pA/ ℃ with variation of temperature, and Vin-Vout is with 2nV/ ℃ only of variation of temperature.In sum, this circuit has realized that output voltage V out follows the low deviation of input voltage vin, and changes with variation of temperature hardly.
Embodiment 2:
Avoid occurring the high-frequency self-excitation vibration for steady operation, add the high frequency negative feedback network in the circuit in embodiment 1, between the positive output end of capacitor C 1 access operational amplifier U1A and the inverting input of operational amplifier U1B.
Embodiment 3:
When the current driving ability of exporting is not enough, add the driving intensifier circuit in the circuit in embodiment 1, the output of operational amplifier inserts the base stage of triode Q1.
Claims (3)
1, a kind of voltage follower circuit is characterized in that, form by the operational amplifier and the resistance (R1, R2) of two parameter unanimities, wherein:
The electrode input end of operational amplifier (U1A) meets the output voltage V out of voltage follower, the resistance (R1) of the negative input of operational amplifier (U1A) and series connection is with after resistance (R2) is connected, receive the negative input of operational amplifier (U1B), and the output of operational amplifier (U1A) is connected with resistance (R2) with resistance (R1);
The output voltage V out of the output termination voltage follower of operational amplifier (U1B), the electrode input end of operational amplifier (U1B) connects the input voltage vin of voltage follower.
2, according to the described voltage follower circuit of claim 1, it is characterized in that, when the high-frequency self-excitation vibration occurring, add the high frequency negative feedback network, between the positive output end of electric capacity (C1) access operational amplifier (U1A) and the inverting input of operational amplifier (U1B).
According to the described voltage follower circuit of claim 1, it is characterized in that 3, when the current driving ability of exporting is not enough, add the driving intensifier circuit, the output of operational amplifier inserts the base stage of triode (Q1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200080374U CN201156720Y (en) | 2007-08-22 | 2007-08-22 | Circuit of voltage follower |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200080374U CN201156720Y (en) | 2007-08-22 | 2007-08-22 | Circuit of voltage follower |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201156720Y true CN201156720Y (en) | 2008-11-26 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2007200080374U Expired - Fee Related CN201156720Y (en) | 2007-08-22 | 2007-08-22 | Circuit of voltage follower |
Country Status (1)
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| CN (1) | CN201156720Y (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101820255A (en) * | 2010-04-12 | 2010-09-01 | 湖北大学 | Voltage follower for high voltage input |
| CN102457237A (en) * | 2010-10-29 | 2012-05-16 | 贵州华阳电工有限公司 | Single-power supply diverging/amplifying circuit |
| CN103558251A (en) * | 2013-10-30 | 2014-02-05 | 成都市宏山科技有限公司 | High-precision relative humidity detection device |
| CN107356850A (en) * | 2017-06-12 | 2017-11-17 | 中国航空工业集团公司西安飞行自动控制研究所 | A kind of self-oscillatory solution method of AC signal process circuit |
| CN110319485A (en) * | 2019-05-28 | 2019-10-11 | 湖北英特吉新能源科技有限公司 | A kind of novel central heating control system and method |
-
2007
- 2007-08-22 CN CNU2007200080374U patent/CN201156720Y/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101820255A (en) * | 2010-04-12 | 2010-09-01 | 湖北大学 | Voltage follower for high voltage input |
| CN102457237A (en) * | 2010-10-29 | 2012-05-16 | 贵州华阳电工有限公司 | Single-power supply diverging/amplifying circuit |
| CN103558251A (en) * | 2013-10-30 | 2014-02-05 | 成都市宏山科技有限公司 | High-precision relative humidity detection device |
| CN107356850A (en) * | 2017-06-12 | 2017-11-17 | 中国航空工业集团公司西安飞行自动控制研究所 | A kind of self-oscillatory solution method of AC signal process circuit |
| CN107356850B (en) * | 2017-06-12 | 2020-06-09 | 中国航空工业集团公司西安飞行自动控制研究所 | Solution method for self-oscillation of alternating current signal processing circuit |
| CN110319485A (en) * | 2019-05-28 | 2019-10-11 | 湖北英特吉新能源科技有限公司 | A kind of novel central heating control system and method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| DD01 | Delivery of document by public notice |
Addressee: Xu Xiulan Document name: Notification of Termination of Patent Right |
|
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20081126 Termination date: 20090922 |