CN117955445A - Adaptive variable gain operation circuit, electronic system and working method - Google Patents

Abstract

The present invention provides an adaptive variable gain arithmetic circuit, comprising: the circuit comprises an operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor and a voltage stabilizing tube; the inverting input end of the operational amplifier is connected with the reference ground through a first resistor, the non-inverting input end of the operational amplifier is connected with an input signal through a second resistor, and the output end of the operational amplifier generates an output signal; the first end of the third resistor is connected with the inverting input end of the operational amplifier, and the second end of the third resistor is connected with the output end of the operational amplifier; the anode end of the voltage stabilizing tube is connected with the inverting input end of the operational amplifier, and the cathode end of the voltage stabilizing tube is connected with the output end of the operational amplifier; the first end of the fourth resistor is connected with the non-inverting input end of the operational amplifier, and the second end of the fourth resistor is connected with the reference ground. The self-adaptive variable gain operation circuit provided by the invention solves a plurality of problems existing in the prior operation circuit when the motor current is measured.

Description

Adaptive variable gain operation circuit, electronic system and working method

Technical Field

The present invention relates to the field of integrated circuit design, and in particular, to a self-adaptive variable gain operation circuit, an electronic system and a working method thereof.

Background

In the motor control process, the current is smaller in the normal working state of the motor, especially in the light load state, the sampling precision requirement of the control system on the current is higher, and the current is far larger than the normal working current in abnormal states such as locked rotor, short circuit and overcurrent; thus, current measurement spans are large, which presents challenges to current sampling resolution and accuracy.

The existing current measurement scheme is as follows:

1. Single gain class: an operational circuit (such as a differential proportion operational circuit) is constructed by adopting an operational amplifier with fixed gain, and current is linearly amplified in a full range by the fixed gain, so that a current range of normal operation is concentrated in a low range of a measuring range, and abnormal large current is concentrated in a high range of the measuring range, therefore, the utilization rate of the whole measuring range is low, and the resolution and the precision of the normal operation current range are low.

2. Redundant channel class: the method is realized by a plurality of operational amplifiers through redundant channels, each channel is provided with different gains, and the software determines which channel output value is used. Multiple operational amplifiers lead to the increase of cost in multiple times, the utilization rate of a single operational amplifier is low, and software processing is complex; in addition, the line connection of the multi-channel input ends is easy to influence each other, so that the measurement accuracy is uncontrollable.

3. Programmable (variable) gain class: the gain structure of the switching circuit is realized by adopting a plurality of switching elements, the switch combination is required to be determined firstly and the switch combination works with the determined gain, and the gain is basically still a fixed gain circuit and cannot be automatically and dynamically adjusted according to signals; even if the switch is switched in the working process, the switching noise is easy to reduce the measurement precision, and the dynamic response is difficult to ensure.

In view of this, how to design a new arithmetic circuit, which can not only consider the resolution and precision at the low range, but also measure the abnormal heavy current, is a technical problem that the skilled person is urgent to solve.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide an adaptive variable gain computing circuit, an electronic system and a working method thereof, which are used for solving a plurality of problems existing in the prior art when the computing circuit measures the motor current.

To achieve the above and other related objects, the present invention provides an adaptive variable gain operation circuit including: the circuit comprises an operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor and a voltage stabilizing tube;

The inverting input end of the operational amplifier is connected with the reference ground through the first resistor, the non-inverting input end of the operational amplifier is connected with an input signal through the second resistor, and the output end of the operational amplifier generates an output signal;

The first end of the third resistor is connected with the inverting input end of the operational amplifier, and the second end of the third resistor is connected with the output end of the operational amplifier;

The anode end of the voltage stabilizing tube is connected with the inverting input end of the operational amplifier, and the cathode end of the voltage stabilizing tube is connected with the output end of the operational amplifier;

The first end of the fourth resistor is connected with the non-inverting input end of the operational amplifier, and the second end of the fourth resistor is connected with the reference ground.

Optionally, the second end of the fourth resistor replaces the reference ground with a bias voltage.

Optionally, the number of the voltage stabilizing tubes is greater than or equal to 1, wherein when the number of the voltage stabilizing tubes is greater than or equal to 2, a plurality of the voltage stabilizing tubes are connected in series.

Optionally, the resistance of the first resistor is equal to the resistance of the second resistor, and the resistance of the third resistor is equal to the resistance of the fourth resistor.

Optionally, the resistance value of the third resistor is larger than the resistance value of the first resistor.

Optionally, the adaptive variable gain operation circuit further includes: and the fifth resistor is connected between the cathode end of the voltage stabilizing tube and the output end of the operational amplifier.

Optionally, the resistance value of the third resistor is greater than the resistance value of the fifth resistor.

The present invention also provides an electronic system comprising: an adaptive variable gain operation circuit as claimed in any preceding claim.

Optionally, the electronic system comprises a motor control system, wherein the adaptive variable gain computing circuit is configured to measure motor current.

The invention also provides a working method of the adaptive variable gain operation circuit, which comprises the following steps:

When the input signal is a small signal, the voltage stabilizing tube is in a high-resistance state, and the self-adaptive variable gain operation circuit works in a linear amplification area with fixed gain;

When the input signal is a large signal, the voltage stabilizing tube is in a clamping state, and the self-adaptive variable gain operation circuit works in a nonlinear amplification area with non-fixed gain;

The fixed gain corresponding to the linear amplifying region is larger than the maximum gain corresponding to the nonlinear amplifying region.

As described above, the adaptive variable gain operation circuit, the electronic system and the operating method of the present invention, based on the design of the adaptive variable gain operation circuit, realize that a larger gain is adopted at a low range (i.e., for normal operating current) to improve the resolution and accuracy of a small signal, and a smaller gain is adopted at a high range (i.e., for abnormal large current) to be compatible with the measurement requirement of a large signal; the invention not only can consider the resolution and the precision at the low range, but also can consider the measurement of the abnormal large signal, and ensures the continuity of the system. The invention has the advantages of high range utilization rate, high response bandwidth and simple structure.

Drawings

Fig. 1 is a schematic circuit diagram of an adaptive variable gain circuit according to the present invention.

Fig. 2 is a schematic diagram of another adaptive variable gain circuit according to the present invention.

Fig. 3 shows an output characteristic curve of the adaptive variable gain operation circuit shown in fig. 1.

Detailed Description

Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.

Please refer to fig. 1 to 3. It should be noted that, the illustrations provided in the present embodiment are merely schematic illustrations of the basic concepts of the present invention, and only the components related to the present invention are shown in the illustrations, rather than being drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of each component in actual implementation may be arbitrarily changed, and the layout of the components may be more complex.

As shown in fig. 1, the present embodiment provides an adaptive variable gain operation circuit including: the circuit comprises an operational amplifier OP1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a voltage regulator DZ1; the inverting input end of the operational amplifier OP1 is connected with the reference ground through a first resistor R1, the non-inverting input end of the operational amplifier OP1 is connected with an input signal Vi through a second resistor R2, and the output end of the operational amplifier OP1 generates an output signal Vo; the first end of the third resistor R3 is connected with the inverting input end of the operational amplifier OP1, and the second end of the third resistor R3 is connected with the output end of the operational amplifier OP 1; the anode end of the voltage stabilizing tube DZ1 is connected with the inverting input end of the operational amplifier OP1, and the cathode end is connected with the output end of the operational amplifier OP 1; the first end of the fourth resistor R4 is connected with the non-inverting input end of the operational amplifier OP1, and the second end of the fourth resistor R is connected with the reference ground.

Further, as shown in fig. 1, the adaptive variable gain operation circuit further includes: the fifth resistor R5 is connected between the cathode terminal of the regulator tube DZ1 and the output terminal of the operational amplifier OP 1.

Since the second terminal of the fourth resistor R4 is connected to the ground, the output signal Vo should ideally be 0 when the input signal Vi is 0; however, in practical applications, the output signal Vo may not be 0 when the input signal Vi is 0, which may cause output distortion, thereby affecting measurement accuracy.

To avoid output distortion, the bias voltage Vref may be used instead of the reference ground, i.e. the second terminal of the fourth resistor R4 is connected to the bias voltage Vref, as shown in fig. 2; the magnitude of the bias voltage Vref may be selected according to the specific application requirements, which is not limited in this embodiment.

The adaptive variable gain operation circuit of the embodiment works in a linear amplification region with fixed gain when the input signal Vi is a small signal, and works in a nonlinear amplification region with non-fixed gain when the input signal Vi is a large signal, so that the resolution and precision of the small signal are improved by adopting a larger gain at a low range, and the measurement requirement of the large signal is met by adopting a smaller gain at a high range.

Specifically, the resistors (e.g., the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, and the fifth resistor R5) according to the present embodiment may be single resistors, or may be equivalent resistors formed by connecting multiple resistors (i.e., greater than or equal to 2) in series and/or parallel, which has no influence on the present embodiment.

More specifically, the resistance of the first resistor R1 is set to be equal to the resistance of the second resistor R2, and the resistance of the third resistor R3 is set to be equal to the resistance of the fourth resistor R4; in practical applications, in order to obtain a larger gain, the resistance of the third resistor R3 may be set to be greater than the resistance of the first resistor R1. Further, the resistance of the third resistor R3 is set to be greater than the resistance of the fifth resistor R5, and even the resistance of the third resistor R3 is far greater than the resistance of the fifth resistor R5.

Specifically, the number of the voltage-stabilizing tubes DZ1 according to the present embodiment is 1 or more, wherein when the number of the voltage-stabilizing tubes DZ1 is 2 or more, the plurality of voltage-stabilizing tubes DZ1 are connected in series. In this embodiment, the turning points from the linear amplifying region to the nonlinear amplifying region are set by using the stable voltages of the voltage-stabilizing tubes DZ1, when the number of the voltage-stabilizing tubes DZ1 is 1, the stable voltages of the 1 voltage-stabilizing tubes are the voltage values corresponding to the turning points, and when the number of the voltage-stabilizing tubes DZ1 is multiple (i.e. greater than or equal to 2), the sum of the stable voltages of the voltage-stabilizing tubes is the voltage value corresponding to the turning points. In practical applications, the voltage value corresponding to the turning point can be set according to practical requirements, which is not limited in this embodiment.

As an example, when the number of the voltage-stabilizing tubes DZ1 is 2 or more, at least 2 of the voltage-stabilizing tubes DZ1 have the same stable voltage; for example, the stable voltages of only 2 of the plurality of voltage stabilizing tubes may be the same, or the stable voltages of 3 or more of the plurality of voltage stabilizing tubes may be the same, or even the stable voltages of all of the plurality of voltage stabilizing tubes may be the same.

As another example, when the number of the voltage-stabilizing tubes DZ1 is 2 or more, at least 2 of the voltage-stabilizing tubes DZ1 have different stabilizing voltages; for example, the stable voltages of only 2 of the plurality of voltage stabilizing tubes may be different, or the stable voltages of 3 or more of the plurality of voltage stabilizing tubes may be different, or even the stable voltages of all of the plurality of voltage stabilizing tubes may be different.

Correspondingly, the embodiment also provides a working method of the adaptive variable gain operation circuit, which comprises the following steps.

Step a: when the input signal Vi is a small signal, the regulator DZ1 is in a high-impedance state, and the adaptive variable gain operation circuit operates in a linear amplification region with fixed gain.

The method comprises the following steps: the input signal Vi is a small voltage signal and limited by a limited amplification proportion, the output of the self-adaptive variable gain operation circuit is in a small level, the voltage stabilizing tube DZ1 is in a high-resistance state, and the self-adaptive variable gain operation circuit is a typical differential subtraction operation circuit at the moment, and the output characteristic of the self-adaptive variable gain operation circuit is in linear change;

for the adaptive variable gain operation circuit shown in fig. 2 at this time, the formula is satisfied:

since u+=u-, therefore,

Let r1=r2, r3=r4, so

For the adaptive variable gain circuit shown in fig. 1, the second end of the fourth resistor R4 is connected to the ground, i.e., vref=0

Wherein U+ is the voltage value of the non-inverting input end of the operational amplifier OP1, U-is the voltage value of the inverting input end of the operational amplifier OP1, R1 is the resistance value of the first resistor, R2 is the resistance value of the second resistor, R3 is the resistance value of the third resistor, R4 is the resistance value of the fourth resistor, vi is the voltage value of the input signal, vo is the voltage value of the output signal, and Vref is the bias voltage.

It can be seen that when the adaptive variable gain computing circuit operates in a linear amplification region with a fixed gain, the corresponding gain is determined by the ratio (R3/R1) of the third resistor R3 to the first resistor R1.

Step b: when the input signal Vi is a large signal, the regulator DZ1 is in a clamped state, and the adaptive variable gain operation circuit operates in a nonlinear amplification region with non-fixed gain.

The method comprises the following steps: the input signal Vi is a large voltage signal, the output of the self-adaptive variable gain operation circuit is in a higher level after being amplified, so that the voltage stabilizing tube DZ1 is in a clamping state, and at the moment, the output characteristic of the self-adaptive variable gain operation circuit is changed, and the output characteristic is not changed linearly but is changed in a nonlinear manner;

for the adaptive variable gain operation circuit shown in fig. 2 at this time, the formula is satisfied:

since u+=u-, therefore,

Let r1=r2, r3=r4, so

If R5< < R3, based onThe upper formula is deformed to obtainThen/>

For the adaptive variable gain circuit shown in fig. 1, the second end of the fourth resistor R4 is connected to the ground, i.e., vref=0

If R5< < R3, then

Wherein U+ is the voltage value of the non-inverting input end of the operational amplifier OP1, U-is the voltage value of the inverting input end of the operational amplifier OP1, R1 is the resistance value of the first resistor, R2 is the resistance value of the second resistor, R3 is the resistance value of the third resistor, R4 is the resistance value of the fourth resistor, R5 is the resistance value of the fifth resistor, vi is the voltage value of the input signal, vo is the voltage value of the output signal, vref is the bias voltage, and Vz is the stable voltage of the voltage regulator tube.

It can be seen that when the adaptive variable gain operation circuit is operated in the nonlinear amplification region with non-fixed gain, the corresponding gain can be approximately regarded as the ratio of the third resistor R3 to the sum of the first resistor R1 and the third resistor R3Determine, and is less than/>It should be noted that, if the adaptive variable gain operation circuit includes the fifth resistor R5, the gain of the linear amplification region is not affected, but the gain of the nonlinear amplification region can be obtained by setting R5 in the correlation formula to 0, which is the same as the result obtained by making R5< < R3.

Therefore, the adaptive variable gain operation circuit of the embodiment has the advantages that the gain corresponding to the linear amplification region is larger than the maximum gain corresponding to the nonlinear amplification region, the resolution and the precision of small signals are improved by adopting larger gain at a low range, and the measurement requirement of large signals is met by adopting smaller gain at a high range.

Correspondingly, the embodiment also provides an electronic system, which comprises: the adaptive variable gain arithmetic circuit described above. Optionally, the electronic system comprises a motor control system, wherein the adaptive variable gain computing circuit is configured to measure motor current.

As shown in fig. 3, since the abnormally large current is generally large, it is not generally in the nonlinear transition region, and the gain of the nonlinear amplification region can be approximately regarded as gain 2 without considering the nonlinear transition region; at this time, when the adaptive variable gain arithmetic circuit of the present embodiment is employed to measure the motor current:

If the motor current is normal, the adaptive variable gain circuit operates in a linear amplification region, such as gain 1 in fig. 3; if the motor current is abnormally high, the adaptive variable gain operation circuit works in a nonlinear amplification area, such as a gain section 2 in fig. 3; the gain 1 is larger than the gain 2, so that the resolution and the accuracy of normal working current are improved by adopting a larger gain at a low range, and the measurement requirement of abnormally large current is met by adopting a smaller gain at a high range.

Comparing the case of measuring the motor current with the arithmetic circuit with a fixed gain, as shown by the gain in the broken line in fig. 3, it can be seen that: the embodiment obviously improves the range utilization rate. In addition, compared with the existing operation circuit adopting a switch switching mode, the embodiment also improves the response bandwidth.

In summary, according to the adaptive variable gain operation circuit, the electronic system and the working method of the present invention, based on the design of the adaptive variable gain operation circuit, the resolution and the precision of the small signal are improved by adopting a larger gain at a low range (i.e. for normal working current), and the measurement requirement of the large signal is compatible by adopting a smaller gain at a high range (i.e. for abnormal large current); the invention not only can consider the resolution and the precision at the low range, but also can consider the measurement of the abnormal large signal, and ensures the continuous inertia of the system. The invention has the advantages of high range utilization rate, high response bandwidth and simple structure. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims (10)

1. An adaptive variable gain operation circuit, the adaptive variable gain operation circuit comprising: the circuit comprises an operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor and a voltage stabilizing tube;

The inverting input end of the operational amplifier is connected with the reference ground through the first resistor, the non-inverting input end of the operational amplifier is connected with an input signal through the second resistor, and the output end of the operational amplifier generates an output signal;

The first end of the third resistor is connected with the inverting input end of the operational amplifier, and the second end of the third resistor is connected with the output end of the operational amplifier;

The anode end of the voltage stabilizing tube is connected with the inverting input end of the operational amplifier, and the cathode end of the voltage stabilizing tube is connected with the output end of the operational amplifier;

The first end of the fourth resistor is connected with the non-inverting input end of the operational amplifier, and the second end of the fourth resistor is connected with the reference ground.

2. The adaptive variable gain circuit of claim 1 wherein the second terminal of the fourth resistor replaces a reference ground with a bias voltage.

3. The adaptive variable gain operation circuit according to claim 1, wherein the number of the voltage-stabilizing tubes is 1 or more, and wherein when the number of the voltage-stabilizing tubes is 2 or more, a plurality of the voltage-stabilizing tubes are connected in series.

4. The adaptive variable gain operation circuit according to claim 1, wherein a resistance value of the first resistor is equal to a resistance value of the second resistor, and a resistance value of the third resistor is equal to a resistance value of the fourth resistor.

5. The adaptive variable gain operation circuit according to claim 4, wherein a resistance value of the third resistor is larger than a resistance value of the first resistor.

6. The adaptive variable gain operation circuit according to any one of claims 1 to 5, further comprising: and the fifth resistor is connected between the cathode end of the voltage stabilizing tube and the output end of the operational amplifier.

7. The adaptive variable gain operation circuit according to claim 6, wherein a resistance value of the third resistor is larger than a resistance value of the fifth resistor.

8. An electronic system, the electronic system comprising: an adaptive variable gain operation circuit as claimed in any one of claims 1 to 7.

9. The electronic system of claim 8, wherein the electronic system comprises a motor control system, wherein,

The adaptive variable gain operation circuit is used for measuring motor current.

10. A method of operating an adaptive variable gain operating circuit as claimed in any one of claims 1 to 7, the method comprising:

When the input signal is a small signal, the voltage stabilizing tube is in a high-resistance state, and the self-adaptive variable gain operation circuit works in a linear amplification area with fixed gain;

When the input signal is a large signal, the voltage stabilizing tube is in a clamping state, and the self-adaptive variable gain operation circuit works in a nonlinear amplification area with non-fixed gain;

The fixed gain corresponding to the linear amplifying region is larger than the maximum gain corresponding to the nonlinear amplifying region.