CN116908553A - Measuring method and circuit for DC gain of operational amplifier ring - Google Patents
Measuring method and circuit for DC gain of operational amplifier ring Download PDFInfo
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- CN116908553A CN116908553A CN202310871267.7A CN202310871267A CN116908553A CN 116908553 A CN116908553 A CN 116908553A CN 202310871267 A CN202310871267 A CN 202310871267A CN 116908553 A CN116908553 A CN 116908553A
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- 238000005259 measurement Methods 0.000 claims abstract description 30
- 239000003990 capacitor Substances 0.000 claims description 10
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/28—Measuring attenuation, gain, phase shift or derived characteristics of electric four pole networks, i.e. two-port networks; Measuring transient response
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Abstract
The application belongs to the technical field of direct current brushless motor control, and provides a method and a circuit for measuring direct current gain of an operational amplifier ring, wherein the measuring circuit comprises the following steps: the operation amplifier circuit to be tested comprises an operation amplifier to be tested; an auxiliary measurement circuit comprising a switch; the switch is connected to the output end of the operational amplifier to be tested, and the non-inverting input end of the operational amplifier to be tested is connected to external voltage; when the switch is disconnected, measuring a first voltage of a non-inverting input end of the operational amplifier to be tested; when the switch is closed, measuring a second voltage of a non-inverting input end of the operational amplifier to be tested; and calculating the open-loop direct-current gain of the operational amplifier to be tested according to the difference value of the first voltage and the second voltage.
Description
Technical Field
The application relates to the technical field of direct current brushless motor control, in particular to a method and a circuit for measuring direct current gain of an operational amplifier ring.
Background
The parameters of the operational amplifier are important and are not needed to be described in detail, but the parameters are limited by the precision of the measuring equipment or the influence caused by temperature drift, external interference and the like of the operational amplifier when the parameters are measured, so that the measuring result is inaccurate. Operational amplifiers are extremely high gain amplifiers with differential inputs, single ended outputs, commonly used in high precision analog circuits, and therefore their performance must be measured accurately. But in open loop measurements the open loop gain may be as high as 107 or higher, and pick-up, stray currents or seebeck (thermocouple) effects may produce very small voltages at the amplifier input, so that errors will be unavoidable. The traditional method for measuring the DC gain of the operational amplifier ring has the defects of inaccuracy and instability.
The conventional operational amplifier gain measurement method comprises the following steps: measurement by definition: the voltage input Vin is attenuated by 101 times by the voltage division of the resistors R1 and R2, and is applied to the input end of the operational amplifier. For different direct-current voltage signals Vin, corresponding output direct-current signals Vout of the operational amplifier are measured, a relation curve between input and output can be drawn, the curve is regressed by a straight line, and the open-loop gain of the operational amplifier can be obtained by the slope of the straight line. The operational amplifier gain is measured by the scheme, and although the concept is clear and the circuit is simple, the operational amplifier gain is not a practical measuring circuit, because the operational amplifier circuit with an open loop is unstable. The open loop gain of an op-amp is very large, typically from 5 th power of 10 to 8 th power of 10. By directly using the operational amplifier open loop measurement scheme, any WeChat interference signal (the interference signal induced by the lead wire, the primary battery generated by the connector lug and the thermocouple effect) in the circuit can cause the output of the operational amplifier to generate great fluctuation and even enter a saturated state. Multiplexing auxiliary operational amplifier, connecting feedback of an attenuation signal, measuring amplified error, and reversely pushing open loop gain. The gain is Vs/[ Vo (Ri/(Ri+Rf)) ], because the measured operational amplifier and the auxiliary operational amplifier have inherent input offset voltage, the obtained open-loop direct current gain has certain error, the auxiliary operational amplifier is connected into an open-loop form for obtaining the maximum amplification of the measured signal, and the full-bandwidth work is easy to amplify the interference signals such as the interference signals induced by the lead wires, thereby further bringing about measurement errors.
Disclosure of Invention
The application aims to solve the problems, and accurately and stably measure the open-loop direct-current gain of the operational amplifier under the condition of not needing to participate in a precise instrument.
The technical scheme provided by the application is as follows:
in some embodiments, the application provides a measurement circuit for dc gain of an operational amplifier ring, comprising:
the operation amplifier circuit to be tested comprises an operation amplifier to be tested;
an auxiliary measurement circuit comprising a switch;
the switch is connected to the output end of the operational amplifier to be tested, and the non-inverting input end of the operational amplifier to be tested is connected to external voltage; when the switch is disconnected, measuring a first voltage of a non-inverting input end of the operational amplifier to be tested; when the switch is closed, measuring a second voltage of a non-inverting input end of the operational amplifier to be tested; and calculating the open-loop direct-current gain of the operational amplifier to be tested according to the difference value of the first voltage and the second voltage.
In some embodiments, the operational amplifier circuit under test further includes: the first voltage dividing resistor and the second voltage dividing resistor;
the first voltage dividing resistor is connected with the positive input end of the operational amplifier to be tested, and the second voltage dividing resistor is connected with the positive input end of the operational amplifier to be tested and the output end of the operational amplifier to be tested and is used for dividing the voltage of the operational amplifier to be tested;
the voltage divided by the first voltage dividing resistor and the second voltage dividing resistor is connected to the output end of the operational amplifier to be measured, and the voltage of the operational amplifier to be measured is calculated by measuring the voltage of the output end of the operational amplifier to be measured.
In some embodiments, the auxiliary measurement circuit further comprises: a third voltage dividing resistor and a fourth voltage dividing resistor;
the third voltage dividing resistor is connected with the output end of the operational amplifier to be tested and the switch, and the fourth voltage dividing resistor is connected with the switch and the external voltage and used for dividing the voltage of the switch, so that the output end of the operational amplifier to be tested is connected with the external voltage after the switch is closed.
In some embodiments, the auxiliary measurement circuit further comprises: an auxiliary operational amplifier, an analog-to-digital converter;
the inverting input end of the auxiliary operational amplifier is connected with the third voltage dividing resistor;
the non-inverting input end of the auxiliary operational amplifier is grounded, and the input end of the auxiliary operational amplifier is connected with the second voltage dividing resistor, the inverting input end of the auxiliary operational amplifier and the analog-to-digital converter;
the auxiliary operational amplifier outputs the first voltage and the second voltage to the analog-to-digital converter for calculating an open-loop direct-current gain of the operational amplifier to be tested.
In some embodiments, the auxiliary measurement circuit further comprises: an auxiliary capacitor;
the auxiliary capacitor is connected between the inverting input end of the auxiliary operational amplifier and the output end of the auxiliary operational amplifier and used for limiting the working frequency interval of the auxiliary operational amplifier so as to measure the output voltage of the auxiliary operational amplifier.
In some embodiments, the present application further provides a method for measuring dc gain of an operational amplifier ring, including:
the switch of the auxiliary measuring circuit is connected with the output end of the operational amplifier to be measured, and the non-inverting input end of the operational amplifier to be measured is connected with external voltage;
when the switch is disconnected, measuring a first voltage of a non-inverting input end of the operational amplifier to be tested;
when the switch is closed, measuring a second voltage of a non-inverting input end of the operational amplifier to be tested;
and calculating the open-loop direct-current gain of the operational amplifier to be tested according to the difference value of the first voltage and the second voltage.
In some embodiments, further comprising:
dividing the voltage of the operational amplifier to be tested through a first voltage dividing resistor and a second voltage dividing resistor of the operational amplifier to be tested;
the voltage divided by the first voltage dividing resistor and the second voltage dividing resistor is connected to the output end of the operational amplifier to be tested;
and calculating the voltage of the operational amplifier to be tested by measuring the voltage of the output end of the operational amplifier to be tested.
In some embodiments, further comprising:
and the voltage of the switch is divided by a third voltage dividing resistor and a fourth voltage dividing resistor of the auxiliary measuring circuit, so that the output end of the operational amplifier to be tested is connected to the external voltage after the switch is closed.
In some embodiments, further comprising:
and outputting the first voltage and the second voltage to an analog-to-digital converter of the auxiliary measuring circuit through an auxiliary operational amplifier of the auxiliary measuring circuit so as to calculate the open-loop direct-current gain of the operational amplifier to be measured.
In some embodiments, further comprising:
and limiting the working frequency interval of the auxiliary operational amplifier through the auxiliary capacitor of the auxiliary measuring circuit so as to measure the output voltage of the auxiliary operational amplifier.
The method and the circuit for measuring the DC gain of the operational amplifier ring have the following advantages: the application provides a circuit for measuring input offset voltage, which measures the input offset voltage when a switch is closed or opened so as to calculate open-loop direct current gain, and has the advantages of simple circuit, stable output and accurate measurement, and reduces errors caused by interference.
Drawings
The above characteristics, technical features, advantages and implementation manners of an operational amplifier ring dc gain measuring method and circuit will be further described with reference to the accompanying drawings in a clearly understood manner.
FIG. 1 is a schematic diagram of one embodiment of an operational open loop DC gain measurement circuit according to the present application;
fig. 2 is a schematic diagram of an embodiment of an operational amplifier ring dc gain measurement circuit according to the present application.
Detailed Description
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following description will explain the specific embodiments of the present application with reference to the accompanying drawings. It is evident that the drawings in the following description are only examples of the application, from which other drawings and other embodiments can be obtained by a person skilled in the art without inventive effort.
For the sake of simplicity of the drawing, the parts relevant to the present application are shown only schematically in the figures, which do not represent the actual structure thereof as a product. Additionally, in order to simplify the drawing for ease of understanding, components having the same structure or function in some of the drawings are shown schematically with only one of them, or only one of them is labeled. Herein, "a" means not only "only this one" but also "more than one" case.
In the present application, the op-amp: an operational amplifier (OPA) is an amplifying circuit capable of performing mathematical operations on signals.
Input offset voltage: when the operational amplifier is used, the direct current output voltage of the amplifier is 0V, and the direct current voltage between the two input ends is loaded.
Open loop dc gain: the differential mode voltage gain of the integrated operational amplifier in the state without feedback resistance is the ratio of the output voltage of the integrated operational amplifier to the differential input voltage.
In one embodiment, as shown in fig. 1, the present application provides a measuring circuit for dc gain of an operational amplifier, comprising:
the operation and discharge circuit to be tested 100, the operation and discharge circuit to be tested includes an operational amplifier to be tested;
an auxiliary measurement circuit 200 comprising a switch;
the switch is connected to the output end of the operational amplifier to be tested, and the non-inverting input end of the operational amplifier to be tested is connected to external voltage; when the switch is disconnected, measuring a first voltage of a non-inverting input end of the operational amplifier to be tested; when the switch is closed, measuring a second voltage of a non-inverting input end of the operational amplifier to be tested; and calculating the open-loop direct-current gain of the operational amplifier to be tested according to the difference value of the first voltage and the second voltage.
In one embodiment, as shown in fig. 2, the present application provides a measuring circuit for dc gain of an operational amplifier, comprising:
based on the corresponding relation between the 1 pin and the 3 pin of the operational amplifier to be tested (the previous amplifier), a SW1 branch (used for introducing external 1V voltage) is newly added at the 1 pin, the difference value of the 3 pins under the condition that the SW1 is opened and closed is measured, and the gain of the operational amplifier to be tested is calculated;
the specific 3-pin measurement process is that as the level of the 3-pin is too small, the voltage after the voltage division is connected into the 1-pin of the auxiliary operational amplifier through the voltage division of R2 and R5, the level value of the 1-pin of the auxiliary operational amplifier is measured, and the level value of the 3-pin is calculated;
the 3 pins of the auxiliary operational amplifier are connected with 0V, the 3 pins and the 2 pins of the auxiliary operational amplifier are short, and the 2 pins of the auxiliary operational amplifier are always 0V;
the function of R3 is to divide the branch voltage of SW1 together with R4, so that the pin 1 of the operational amplifier to be tested is connected with 0.5V voltage after SW1 is closed;
the capacitor C1 and the auxiliary operational amplifier form an integrator, the working frequency interval of the auxiliary operational amplifier is limited, and the 1-pin level of the auxiliary operational amplifier is convenient to measure.
In the circuit, the input offset voltage of the DUT is measured twice, so that it is important to understand the input offset voltage and the measurement principle. The offset voltage (Vos) of an ideal operational amplifier is 0, i.e., when the two inputs are connected together and hold an intermediate supply voltage, the output voltage is also the intermediate supply voltage. In reality, the operational amplifier has offset voltages ranging from several microvolts to several millivolts, so that a voltage within this range must be applied to the input terminal to make the output at an intermediate potential.
See first the case where SW1 is off. The auxiliary amplifier as an integrator is configured as an open loop (highest gain) at dc, but its input resistance and feedback capacitance limit its bandwidth to a few Hz. This means that the DC voltage at the DUT output is amplified by the auxiliary amplifier with the highest gain and applied to the DUT non-inverting input through a 1000:1 attenuator. The negative feedback drives the DUT output to ground.
The ADC module takes the output voltage of the auxiliary op-amp, which is 1000 times the correction voltage (equal in magnitude to the input offset voltage) applied to the DUT input, on the order of tens of mV or more, so that measurements can be made quite easily. This voltage is also 1000 times the input offset voltage.
To measure the DUT operational open loop gain, SW1 needs to be closed, a voltage, such as 1V, is applied to force the output of the DUT to change by a certain amount, and the DUT output must become 0.5V in order to keep the input of the auxiliary amplifier unchanged around 0. At this time, the voltage of the output terminal of the auxiliary operational amplifier also changes. The difference between the auxiliary operational amplifier outputs is reduced by 1000 times, and the value of the DUT output divided by the open loop gain of the DUT can be obtained according to the equation.
The following are the measurement steps:
1. SW1 is turned off and the ADC measures the output of the auxiliary op-amp, denoted Voffset1.
2. SW1 is closed and the ADC measures the output of the auxiliary op-amp, denoted Voffset2.
3. The voltage gain was 20log [ 0.5/(Voffset 2-Voffset 1) ×1000] db.
The application does not directly obtain the direct current gain, but obtains the difference value after measuring the offset voltage added twice (no external 1V voltage is added once and 1V voltage is added another time), so that the measuring result is more accurate, and the SW1 controls whether the voltage is added or not.
In one embodiment, the operational amplifier circuit to be tested further includes: a first voltage dividing resistor (R2) and a second voltage dividing resistor (R5);
the first voltage dividing resistor is connected with the positive input end of the operational amplifier to be tested, and the second voltage dividing resistor is connected with the positive input end of the operational amplifier to be tested and the output end of the operational amplifier to be tested and is used for dividing the voltage of the operational amplifier to be tested;
the voltage divided by the first voltage dividing resistor and the second voltage dividing resistor is connected to the output end of the operational amplifier to be measured, and the voltage of the operational amplifier to be measured is calculated by measuring the voltage of the output end of the operational amplifier to be measured.
In one embodiment, the auxiliary measurement circuit further comprises: a third voltage dividing resistor (R3) and a fourth voltage dividing resistor (R4);
the third voltage dividing resistor is connected with the output end of the operational amplifier to be tested and the switch, and the fourth voltage dividing resistor is connected with the switch and the external voltage and used for dividing the voltage of the switch, so that the output end of the operational amplifier to be tested is connected with the external voltage after the switch is closed.
In one embodiment, the auxiliary measurement circuit further comprises: an auxiliary operational amplifier, an analog-to-digital converter;
the inverting input end of the auxiliary operational amplifier is connected with the third voltage dividing resistor;
the non-inverting input end of the auxiliary operational amplifier is grounded, and the input end of the auxiliary operational amplifier is connected with the second voltage dividing resistor, the inverting input end of the auxiliary operational amplifier and the analog-to-digital converter;
the auxiliary operational amplifier outputs the first voltage and the second voltage to the analog-to-digital converter for calculating an open-loop direct-current gain of the operational amplifier to be tested.
In one embodiment, the auxiliary measurement circuit further comprises: an auxiliary capacitor;
the auxiliary capacitor is connected between the inverting input end of the auxiliary operational amplifier and the output end of the auxiliary operational amplifier and used for limiting the working frequency interval of the auxiliary operational amplifier so as to measure the output voltage of the auxiliary operational amplifier.
In one embodiment, the application further provides a method for measuring the dc gain of the operational amplifier ring, which comprises the following steps:
the switch of the auxiliary measuring circuit is connected with the output end of the operational amplifier to be measured, and the non-inverting input end of the operational amplifier to be measured is connected with external voltage;
when the switch is disconnected, measuring a first voltage of a non-inverting input end of the operational amplifier to be tested;
when the switch is closed, measuring a second voltage of a non-inverting input end of the operational amplifier to be tested; and calculating the open-loop direct-current gain of the operational amplifier to be tested according to the difference value of the first voltage and the second voltage.
In one embodiment, further comprising:
dividing the voltage of the operational amplifier to be tested through a first voltage dividing resistor and a second voltage dividing resistor of the operational amplifier to be tested;
the voltage divided by the first voltage dividing resistor and the second voltage dividing resistor is connected to the output end of the operational amplifier to be tested;
and calculating the voltage of the operational amplifier to be tested by measuring the voltage of the output end of the operational amplifier to be tested.
In one embodiment, further comprising:
and the voltage of the switch is divided by a third voltage dividing resistor and a fourth voltage dividing resistor of the auxiliary measuring circuit, so that the output end of the operational amplifier to be tested is connected to the external voltage after the switch is closed.
In one embodiment, further comprising:
and outputting the first voltage and the second voltage to an analog-to-digital converter of the auxiliary measuring circuit through an auxiliary operational amplifier of the auxiliary measuring circuit so as to calculate the open-loop direct-current gain of the operational amplifier to be measured.
In one embodiment, further comprising:
and limiting the working frequency interval of the auxiliary operational amplifier through the auxiliary capacitor of the auxiliary measuring circuit so as to measure the output voltage of the auxiliary operational amplifier.
The application provides a circuit for measuring input offset voltage, which measures the input offset voltage when a switch is closed or opened so as to calculate open-loop direct current gain, and has the advantages of simple circuit, stable output and accurate measurement, and reduces errors caused by interference.
In the foregoing embodiments, the descriptions of the embodiments are focused on, and the parts of a certain embodiment that are not described or depicted in detail may be referred to in the related descriptions of other embodiments.
Those of ordinary skill in the art will appreciate that the elements of the examples described in connection with the embodiments disclosed herein can be implemented as electronic hardware, or as a combination of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
In the embodiments provided in the present application, it should be understood that the disclosed system may be implemented in other manners. The above described embodiments are exemplary only, and exemplary, the division of the modules or units is merely a logical function division, and there may be additional divisions when actually implemented, exemplary, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection via interfaces, devices or units, which may be in electrical, mechanical or other forms.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.
It should be noted that the above embodiments can be freely combined as needed. The foregoing is merely a preferred embodiment of the present application and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present application, which are intended to be comprehended within the scope of the present application.
Claims (8)
1. A measurement circuit for operation open loop dc gain, comprising:
the operation amplifier circuit to be tested comprises an operation amplifier to be tested;
an auxiliary measurement circuit comprising a switch;
the switch is connected to the output end of the operational amplifier to be tested, and the non-inverting input end of the operational amplifier to be tested is connected to external voltage; when the switch is disconnected, measuring a first voltage of a non-inverting input end of the operational amplifier to be tested; when the switch is closed, measuring a second voltage of a non-inverting input end of the operational amplifier to be tested; calculating open-loop direct current gain of the operational amplifier to be tested according to the difference value of the first voltage and the second voltage;
the operational amplifier circuit to be tested further comprises: the first voltage dividing resistor and the second voltage dividing resistor;
the first voltage dividing resistor is connected with the positive input end of the operational amplifier to be tested, and the second voltage dividing resistor is connected with the positive input end of the operational amplifier to be tested and the output end of the operational amplifier to be tested and is used for dividing the voltage of the operational amplifier to be tested;
the voltage divided by the first voltage dividing resistor and the second voltage dividing resistor is connected to the output end of the operational amplifier to be measured, and the voltage of the operational amplifier to be measured is calculated by measuring the voltage of the output end of the operational amplifier to be measured.
2. The operational amplifier ring dc gain measurement circuit of claim 1, wherein the auxiliary measurement circuit further comprises: a third voltage dividing resistor and a fourth voltage dividing resistor;
the third voltage dividing resistor is connected with the output end of the operational amplifier to be tested and the switch, and the fourth voltage dividing resistor is connected with the switch and the external voltage and used for dividing the voltage of the switch, so that the output end of the operational amplifier to be tested is connected with the external voltage after the switch is closed.
3. The operational amplifier ring dc gain measurement circuit of claim 2, wherein the auxiliary measurement circuit further comprises: an auxiliary operational amplifier, an analog-to-digital converter;
the inverting input end of the auxiliary operational amplifier is connected with the third voltage dividing resistor;
the non-inverting input end of the auxiliary operational amplifier is grounded, and the input end of the auxiliary operational amplifier is connected with the second voltage dividing resistor, the inverting input end of the auxiliary operational amplifier and the analog-to-digital converter;
the auxiliary operational amplifier outputs the first voltage and the second voltage to the analog-to-digital converter for calculating an open-loop direct-current gain of the operational amplifier to be tested.
4. A measurement circuit for an operational open loop dc gain as defined in claim 3, wherein said auxiliary measurement circuit further comprises: an auxiliary capacitor;
the auxiliary capacitor is connected between the inverting input end of the auxiliary operational amplifier and the output end of the auxiliary operational amplifier and used for limiting the working frequency interval of the auxiliary operational amplifier so as to measure the output voltage of the auxiliary operational amplifier.
5. The method for measuring the DC gain of the operational amplifier ring is characterized by comprising the following steps of:
the switch of the auxiliary measuring circuit is connected with the output end of the operational amplifier to be measured, and the non-inverting input end of the operational amplifier to be measured is connected with external voltage;
when the switch is disconnected, measuring a first voltage of a non-inverting input end of the operational amplifier to be tested;
when the switch is closed, measuring a second voltage of a non-inverting input end of the operational amplifier to be tested; calculating open-loop direct current gain of the operational amplifier to be tested according to the difference value of the first voltage and the second voltage;
dividing the voltage of the operational amplifier to be tested through a first voltage dividing resistor and a second voltage dividing resistor of the operational amplifier to be tested;
the voltage divided by the first voltage dividing resistor and the second voltage dividing resistor is connected to the output end of the operational amplifier to be tested;
and calculating the voltage of the operational amplifier to be tested by measuring the voltage of the output end of the operational amplifier to be tested.
6. The method for measuring dc gain of an operational amplifier ring of claim 5, further comprising:
and the voltage of the switch is divided by a third voltage dividing resistor and a fourth voltage dividing resistor of the auxiliary measuring circuit, so that the output end of the operational amplifier to be tested is connected to the external voltage after the switch is closed.
7. The method for measuring dc gain of an operational amplifier ring of claim 6, further comprising:
and outputting the first voltage and the second voltage to an analog-to-digital converter of the auxiliary measuring circuit through an auxiliary operational amplifier of the auxiliary measuring circuit so as to calculate the open-loop direct-current gain of the operational amplifier to be measured.
8. The method for measuring dc gain of an operational amplifier ring of claim 7, further comprising:
and limiting the working frequency interval of the auxiliary operational amplifier through the auxiliary capacitor of the auxiliary measuring circuit so as to measure the output voltage of the auxiliary operational amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310871267.7A CN116908553A (en) | 2023-07-17 | 2023-07-17 | Measuring method and circuit for DC gain of operational amplifier ring |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310871267.7A CN116908553A (en) | 2023-07-17 | 2023-07-17 | Measuring method and circuit for DC gain of operational amplifier ring |
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| CN116908553A true CN116908553A (en) | 2023-10-20 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202310871267.7A Pending CN116908553A (en) | 2023-07-17 | 2023-07-17 | Measuring method and circuit for DC gain of operational amplifier ring |
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| CN (1) | CN116908553A (en) |
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- 2023-07-17 CN CN202310871267.7A patent/CN116908553A/en active Pending
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