CN116301147A - Current source circuit and method for reducing influence of output voltage - Google Patents
Current source circuit and method for reducing influence of output voltage Download PDFInfo
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- CN116301147A CN116301147A CN202310027862.2A CN202310027862A CN116301147A CN 116301147 A CN116301147 A CN 116301147A CN 202310027862 A CN202310027862 A CN 202310027862A CN 116301147 A CN116301147 A CN 116301147A
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/10—Regulating voltage or current
- G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
- G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
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Abstract
The invention provides a current source circuit and a method for reducing the influence of output voltage, wherein the circuit comprises: the input signal end, the feedback circuit, the output circuit and the current detection resistor. The feedback circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor and a compensation resistor. The first resistor is disposed between the inverting input terminal and the output terminal. The second resistor is arranged between the inverting input end and the voltage input end, and the fourth resistor and the compensating resistor are arranged between the non-inverting input end and the grounding end in series. One end of the third resistor is connected with the in-phase input end, the other end of the third resistor is connected with one end of the load resistor, the other end of the current detection resistor is connected with the output end, and the junction of the third resistor and the current detection resistor is also connected with an external load. The invention eliminates the influence of the current source output voltage on the current source output current, reduces the influence of the current source output voltage on the current source circuit, and simultaneously keeps the low complexity and low cost of the current source circuit.
Description
Technical Field
The invention relates to the technical field of current sources, in particular to a current source circuit and a method for reducing influence of output voltage.
Background
The current source is one kind of driving circuit, and the main output parameter is current, and under the condition that the input parameter is certain, no matter how the load changes (within a certain range), the output current is unchanged, and it is common to set the input voltage of the current source, and the current source will output corresponding current to the load. Current sources are widely used in various circuits and are also used in large numbers in test meters. In an automatic integrated circuit tester (Automatic Test Equipment, abbreviated as ATE) test apparatus, a lot of use is also made, and compared with a test meter, ATE apparatus requires many channels, is low in cost, and requires simplification of devices in addition to high precision.
Current source implementation circuits are commonly used to form a subtracting circuit from an integrated operational amplifier and multiple resistors. Such a current source circuit is simple, has a small device footprint and is low cost, but practical circuits indicate that the output current of the current source is related not only to the input voltage of the current source, but also to the output voltage of the current source. Variations in the output voltage of the current source can cause variations in the output current of the current source, which can cause a relatively large uncertainty in the actual application of the current source.
One common improvement scheme is: adding a plurality of integrated operational amplifiers and a plurality of resistors; the integrated operational amplifier is used for carrying out follow-up feedback, so that the influence of output voltage can be eliminated/reduced theoretically, the current source of the scheme is stable in output current, but more circuit devices are arranged, the occupied area of the circuit is larger, and the cost is high; a further improvement is to replace the integrated operational amplifier and resistor added in the above improvement with an instrumentation operational amplifier to achieve similar effects, while also having the problems of complex circuitry and high cost.
Disclosure of Invention
The present invention addresses the above-mentioned deficiencies in the prior art by providing a current source circuit and method for reducing the effect of an output voltage to solve at least one of the above-mentioned technical problems.
Specifically, a current source circuit for reducing an influence of an output voltage, comprising: the input signal end, the feedback circuit, the output circuit and the current detection resistor. The feedback circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor and a compensation resistor.
The output circuit includes a non-inverting input, an inverting input, and an output. The first resistor is arranged between the inverting input end and the output end, the second resistor is arranged between the inverting input end and the input signal end, and the fourth resistor and the compensation resistor are arranged between the non-inverting input end and the grounding end in series.
One end of the third resistor is connected with the non-inverting input end, the other end of the third resistor is connected with one end of the current detection resistor, and the other end of the current detection resistor is connected with the output end; and the connection part of the third resistor and the current detection resistor is also connected with an external load.
In the above technical solution, preferably, the output circuit includes an integrated operational amplifier, or a combination of the integrated operational amplifier and a power amplifier.
In the above technical solution, preferably, the resistance values of the first resistor, the second resistor, the third resistor, and the fourth resistor are respectively R 1 、R 2 、R 3 And R is 4 Wherein R is 1 /R 2 =R 3 /R 4 。
In the above technical solution, preferably, at least one of the first resistor, the second resistor, the third resistor, the fourth resistor and the compensation resistor is a resistor with an adjustable resistance value.
In the above technical solution, preferably, the resistance value of the compensation resistor is R K The resistance value of the current detection resistor is R S The resistance values of the third resistor and the fourth resistor are respectively R 3 And R is 4 ；R K =R 4 *R S /R 3 。
In the above technical solution, preferably, the voltage of the input signal terminal is adjustable.
A method for determining a driving voltage, which is applied to the current source circuit, the method comprises:
determining the current required by the current external load;
so that R is 1 /R 2 =R 3 /R 4 Wherein R is 1 、R 2 、R 3 And R is 4 The first resistor, the second resistor, the third resistor and the fourth resistor are respectively;
so that R is K= R 4 *R S /R 3 The method comprises the steps of carrying out a first treatment on the surface of the Wherein R is K R is the resistance of the compensation resistor S The resistance value of the current detection resistor is;
based on
Determining the voltage output by the input signal end; wherein V is set For the voltage of the input signal terminal, I L And the current required by the external load is required.
The method further includes outputting at the input signal terminal based on the determined voltage.
In summary, the current source circuit and the method for reducing the influence of the output voltage have the following advantages: a current source circuit for reducing the effect of an output voltage, comprising: the input signal end, the feedback circuit, the output circuit and the current detection resistor. The feedback circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor and a compensation resistor. A compensation resistor is connected in series beside the fourth resistor, wherein R 1 /R 2 =R 3 /R 4 And compensating resistance R K= R 4 *R S /R 3 When the current source is used, the output current of the current source is irrelevant to the output voltage of the current source, the output current of the current source is only relevant to the input voltage of the current source, the influence of the output voltage of the current source on the output current of the current source is eliminated, the influence of the output voltage of the current source on the current source circuit is reduced, and meanwhile, the low complexity and the low cost of the current source circuit are maintained.
Furthermore, the invention also provides a method for determining the driving voltage, after the determined voltage is output to the input signal end, the current source circuit can output stable current to the load, the output current of the current source circuit is not influenced by the output voltage of the current source, and the stability of the current source circuit is improved.
Drawings
The invention will be further described with reference to the drawings and examples.
Fig. 1 is a circuit diagram of a current source circuit for reducing the influence of an output voltage according to the present invention.
Fig. 2 is a method of determining a driving voltage based on a current source circuit that reduces the effect of an output voltage.
Detailed Description
The conception, specific structure, and technical effects produced by the present invention will be clearly and completely described below with reference to the embodiments and the drawings to fully understand the objects, features, and effects of the present invention.
Hereinafter, various embodiments of the present invention will be described more fully. The invention is capable of various embodiments and of modifications and variations therein. However, it should be understood that: there is no intention to limit the various embodiments of the invention to the specific embodiments disclosed herein, but rather the invention is to be understood to cover all modifications, equivalents, and/or alternatives falling within the spirit and scope of the various embodiments of the invention.
Hereinafter, the terms "comprises" or "comprising" as may be used in various embodiments of the present invention indicate the presence of the disclosed functions, operations or elements, and are not limiting of the addition of one or more functions, operations or elements. Furthermore, as used in various embodiments of the invention, the terms "comprises," "comprising," and their cognate terms are intended to refer to a particular feature, number, step, operation, element, component, or combination of the foregoing, and should not be interpreted as first excluding the existence of or increasing likelihood of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing.
In various embodiments of the invention, the expression "or" at least one of a or/and B "includes any or all combinations of the words listed simultaneously. For example, the expression "a or B" or "at least one of a or/and B" may include a, may include B or may include both a and B.
Expressions (such as "first", "second", etc.) used in the various embodiments of the invention may modify various constituent elements in the various embodiments, but the respective constituent elements may not be limited. For example, the above description does not limit the order and/or importance of the elements. The above description is only intended to distinguish one element from another element. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of various embodiments of the present invention.
It should be noted that: in the present invention, unless explicitly specified and defined otherwise, terms such as "mounted," "connected," "secured," and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium; may be a communication between the interiors of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In the present invention, it should be understood by those of ordinary skill in the art that the terms indicating an orientation or a positional relationship are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of description and simplicity of description, not to indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the invention.
The terminology used in the various embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the various embodiments of the invention. As used herein, the singular is intended to include the plural as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments of the invention belong. The terms (such as those defined in commonly used dictionaries) will be interpreted as having a meaning that is the same as the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein in connection with the various embodiments of the invention.
Fig. 1 is a circuit diagram of a current source circuit for reducing the influence of an output voltage according to the present invention, the current source circuit comprising: the input signal end, the feedback circuit, the output circuit and the current detection resistor.
The output circuit comprises a non-inverting input, an inverting input and an output-side output circuit, which in the first embodiment is comprised as an operational amplifier, or a combination of an operational amplifier and a power amplifier.
The feedback circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor and a compensation resistor. The first resistor is disposed between the inverting input terminal and the output terminal. The second resistor is arranged between the inverting input end and the input signal end, the fourth resistor and the compensating resistor are arranged between the non-inverting input end and the grounding end in series, and the positions of the fourth resistor and the compensating resistor can be mutually converted. One end of the third resistor is connected with the in-phase input end, the other end of the third resistor is connected with one end of the current detection resistor, the other end of the current detection resistor is connected with the output end, and the junction of the third resistor and the current detection resistor is also connected with an external load.
The resistance values of the first resistor, the second resistor, the third resistor and the fourth resistor are R respectively 1 、R 2 、R 3 And R is 4 The resistance value of the compensation resistor is R K . Preferably, the compensation resistor and the fourth resistor can be replaced by a resistor with a resistance equal to R 4 +R k Resistance of (2); can also be replaced by a plurality of resistors, wherein the sum of the resistance values of the plurality of resistors is equal to R 4 +R k The preparation method is finished; for ease of calculation, the description is here divided into a fourth resistor and a compensation resistor.
At least one of the first resistor, the second resistor, the third resistor, the fourth resistor and the compensation resistor is a resistor with adjustable resistance value, and the resistor with adjustable resistance value is used for R 1 /R 2 =R 3 /R 4 (inference and formulas in the following examples, R) 3 /R 4 Can be combined with R 1 /R 2 Mutually substituted) to form a resistive match, preferred embodimentsR in (B) 1 =R 3 ，R 2 =R 4 . The resistance value of the current detection resistor is R S The current detection resistor can be a resistor with a fixed resistance value or an adjustable resistor with an adjustable resistance value. Preferably, the resistance values of the current detection resistor and the compensation resistor satisfy R K =R 4 *R S /R 3 。
As shown in fig. 1, the output terminal of the output circuit is a voltage V 1 The load voltage (output voltage of current source) is V 2 The voltage of the input signal terminal (the input voltage of the current source) is V set The voltage of the input signal end is adjustable, and the current of the load branch (the output current of the current source) is I L The current of the third resistor is I R3 。
The circuit calculation formula (1) in fig. 1 is:
when R is 1 /R 2 =R 3 /R 4 When formula (2) is taken into formula (1), formula (4) is obtained:
when R is K =R 4 *R S /R 3 (equivalent to R K =R 2 *R S /R 1 ) In this case, the value in { } in the formula (4) is 0, and the formula (5) can be obtained:
v in the formula (5) set And I L Edge replacement is carried out to obtain a formula (6):
from equation (6), it can be seen that by providing a compensation resistor R K To compensate I R3 The influence of the output voltage of the current source on the output current of the current source is eliminated. On the basis of the prior art, the invention modifies the resistance matching scheme, proposes a new resistance calculation formula, and simultaneously maintains the characteristics of lower complexity and low cost.
Fig. 2 shows a method for determining a driving voltage based on a current source circuit for reducing the influence of an output voltage according to the present invention. The method comprises the following steps:
first step S1: determining the current required by the current external load;
second step S2: r is R 1 /R 2 =R 3 /R 4 The method comprises the steps of carrying out a first treatment on the surface of the Wherein R is 1 、R 2 、R 3 And R is 4 The first resistor, the second resistor, the third resistor and the fourth resistor are respectively arranged;
third step S3: so that R is K =R 4 *R S /R 3 The method comprises the steps of carrying out a first treatment on the surface of the Wherein R is K To compensate the resistance of the resistor, R S The resistance value of the current detection resistor;
fourth step S4: based on
Determining the voltage output by an input signal end;
fifth step S5: the output is made at the input signal terminal based on the determined voltage.
According to the method for determining the driving voltage, after the determined voltage is output to the input signal end, the current source circuit can output stable current to the load, the output current of the current source circuit cannot be influenced by the output voltage of the current source, and the stability of the current source circuit is improved.
While the preferred embodiment of the present invention has been described in detail, the present invention is not limited to the embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are included in the scope of the present invention as defined in the appended claims.
Claims (8)
1. A current source circuit for reducing the effect of an output voltage, comprising:
the input signal end, the feedback circuit, the output circuit and the current detection resistor;
the feedback circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor and a compensation resistor;
the output circuit comprises a non-inverting input end, an inverting input end and an output end, the first resistor is arranged between the inverting input end and the output end, the second resistor is arranged between the inverting input end and an input signal end, and the fourth resistor and the compensation resistor are arranged between the non-inverting input end and a grounding end in series;
one end of the third resistor is connected with the non-inverting input end, the other end of the third resistor is connected with one end of the current detection resistor, the other end of the current detection resistor is connected with the output end, and the connection part of the third resistor and the current detection resistor is also connected with an external load.
2. A current source circuit for reducing the effect of an output voltage according to claim 1, wherein the output circuit comprises an integrated operational amplifier, or a combination of an integrated operational amplifier and a power amplifier.
3. The current source circuit for reducing output voltage effects according to claim 1, wherein the resistances of said first resistor, said second resistor, said third resistor, and said fourth resistor are each R 1 、R 2 、R 3 And R is 4 Wherein R is 1 /R 2 =R 3 /R 4 。
4. The current source circuit of claim 1, wherein at least one of the first resistor, the second resistor, the third resistor, the fourth resistor, and the compensation resistor is a resistor with an adjustable resistance.
5. The current source circuit for reducing output voltage influence according to claim 1, wherein the compensation resistor has a resistance value of R K The resistance value of the current detection resistor is R S The resistance values of the third resistor and the fourth resistor are respectively R 3 And R is 4 ；R K =R 4 *R S /R 3 。
6. A current source circuit for reducing the effect of an output voltage according to claim 1, wherein the voltage at said input signal terminal is adjustable.
7. A method of determining a driving voltage, applied to the current source circuit of any one of claims 1-6, the method comprising:
determining the current required by the current external load;
so that R is 1 /R 2 =R 3 /R 4 Wherein R is 1 、R 2 、R 3 And R is 4 The first resistor, the second resistor, the third resistor and the fourth resistor are respectively;
so that R is K= R 4 *R S /R 3 The method comprises the steps of carrying out a first treatment on the surface of the Wherein R is K R is the resistance of the compensation resistor S The resistance value of the current detection resistor is;
based on
Determining the voltage of the input signal terminal; wherein V is set For the voltage of the input signal terminal, I L And the current required by the external load is required.
8. The method as recited in claim 7, further comprising: and outputting at the input signal terminal based on the determined voltage.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310027862.2A CN116301147A (en) | 2023-01-09 | 2023-01-09 | Current source circuit and method for reducing influence of output voltage |
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| CN202310027862.2A CN116301147A (en) | 2023-01-09 | 2023-01-09 | Current source circuit and method for reducing influence of output voltage |
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| CN116301147A true CN116301147A (en) | 2023-06-23 |
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| CN202310027862.2A Pending CN116301147A (en) | 2023-01-09 | 2023-01-09 | Current source circuit and method for reducing influence of output voltage |
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