Piecewise linearization circuit based on diode

Abstract

The utility model provides a piecewise linearization circuit based on a diode. The piecewise linearization circuit comprises an operational amplifier, a first circuit and a second circuit, wherein the first circuit and the second circuit are connected with the inverted input end of the operational amplifier; a resistor is arranged between the inverting input end and the output end of the operational amplifier, and the in-phase input end of the operational amplifier is connected with the sensor; a resistor in the first circuit is respectively connected with an inverted input end of the operational amplifier and a positive electrode of a diode, a negative electrode of the diode is connected with a positive electrode of a voltage source, and a negative electrode of the voltage source is grounded; a resistor in the second circuit is connected with the inverted input end of the operational amplifier and the negative electrode of the diode, the positive electrode of the diode is connected with the positive electrode of the voltage source, and the negative electrode of the voltage source is grounded. According to the invention, the diode is adopted to replace a multiplexer, and only one operational amplifier is needed to realize the piecewise linearization function of the input signal of the sensor, so that the circuit structure is simplified, and the cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of signal processing, and in particular to a diode-based piecewise linearization circuit. Background Art

[0002] The piecewise linearization circuit mainly divides the input signal into several linear segments, and replaces the nonlinear characteristic curve with a straight line segment in each segment. Specifically, the piecewise linearization circuit processes the characteristic curve of the nonlinear circuit element piecewise linearly, so that in each segment, the circuit can be approximately regarded as a linear system.

[0003] At present, conventional segmented linearization circuits usually use multiplexers and multiple groups of operational amplifiers in combination with analog switches. However, this not only increases the complexity of the circuit, but also increases the cost. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a diode-based piecewise linearization circuit to solve the technical problems existing in the prior art.

[0005] To achieve the above-mentioned purpose and other related purposes, the present application provides a diode-based piecewise linearization circuit, comprising the following steps:

[0006] An operational amplifier, a first circuit and a second circuit connected to an inverting input terminal of the operational amplifier;

[0007] A resistor is provided between the inverting input terminal and the output terminal of the operational amplifier, and the non-inverting input terminal of the operational amplifier is connected to the sensor;

[0008] The first circuit and the second circuit both include a resistor, a diode and a voltage source;

[0009] In the first circuit, one end of the resistor is connected to the inverting input terminal of the operational amplifier, the other end of the resistor is connected to the anode of the diode, and the cathode of the diode is connected to the anode of the voltage source, and the cathode of the voltage source is grounded;

[0010] In the second circuit, one end of the resistor is connected to the inverting input terminal of the operational amplifier, the other end of the resistor is connected to the cathode of the diode, and the anode of the diode is connected to the anode of the voltage source, and the cathode of the voltage source is grounded.

[0011] In one embodiment of the present application, the first circuit includes:

[0012] One end of the first resistor is connected to the inverting input terminal of the operational amplifier, the other end of the first resistor is connected to the anode of the first diode, and the cathode of the first diode is connected to the anode of the first voltage source, and the cathode of the first voltage source is grounded;

[0013] One end of the second resistor is connected to the inverting input terminal of the operational amplifier, the other end of the second resistor is connected to the anode of the second diode, and the cathode of the second diode is connected to the anode of the second voltage source, and the cathode of the second voltage source is grounded;

[0014] One end of the third resistor is connected to the inverting input terminal of the operational amplifier, the other end of the third resistor is connected to the anode of the third diode, and the cathode of the third diode is connected to the anode of the third voltage source, and the cathode of the third voltage source is grounded;

[0015] One end of the fourth resistor is connected to the inverting input terminal of the operational amplifier, the other end of the fourth resistor is connected to the anode of the fourth diode, and the cathode of the fourth diode is connected to the anode of the fourth voltage source, and the cathode of the fourth voltage source is grounded.

[0016] In one embodiment of the present application, the second circuit includes:

[0017] One end of a fifth resistor is connected to the inverting input terminal of the operational amplifier, the other end of the fifth resistor is connected to the cathode of a fifth diode, and the anode of the fifth diode is connected to the anode of a fifth voltage source, and the cathode of the fifth voltage source is grounded;

[0018] One end of the sixth resistor is connected to the inverting input terminal of the operational amplifier, the other end of the sixth resistor is connected to the cathode of the sixth diode, and the anode of the sixth diode is connected to the anode of the sixth voltage source, and the cathode of the sixth voltage source is grounded;

[0019] One end of the seventh resistor is connected to the inverting input terminal of the operational amplifier, the other end of the seventh resistor is connected to the cathode of the seventh diode, and the anode of the seventh diode is connected to the anode of the seventh voltage source, and the cathode of the seventh voltage source is grounded;

[0020] One end of the eighth resistor is connected to the inverting input terminal of the operational amplifier, the other end of the eighth resistor is connected to the cathode of the eighth diode, and the anode of the eighth diode is connected to the anode of the eighth voltage source, and the cathode of the eighth voltage source is grounded.

[0021] In an embodiment of the present application, the voltage source in the first circuit and the voltage source in the second circuit are respectively located in different voltage ranges.

[0022] In one embodiment of the present application, the eighth voltage source, the seventh voltage source, the sixth voltage source and the fifth voltage source are located in a first voltage range; the fourth voltage source, the third voltage source, the second voltage source and the first voltage source are located in a second voltage range.

[0023] In an embodiment of the present application, the minimum voltage of the second voltage interval is greater than the maximum voltage of the first voltage interval.

[0024] In one embodiment of the present application, the first voltage interval includes a voltage interval corresponding to the sensor input signal at 0ms-15ms;

[0025] The second voltage interval includes a voltage interval corresponding to the sensor input signal at 30ms-45ms.

[0026] In one embodiment of the present application, according to the voltage corresponding to the sensor input signal, the resistance in the first circuit, the resistance in the second circuit, and the resistance between the inverting input terminal and the output terminal of the operational amplifier jointly form gains of different intervals, and the gains are used to perform linear correction on the sensor input signal.

[0027] In one embodiment of the present application, the gain of the voltage interval corresponding to the sensor input signal at 0ms-15ms changes from large to small, and the gain of the voltage interval corresponding to the sensor input signal at 30ms-45ms changes from small to large.

[0028] In one embodiment of the present application, the sensor includes at least one of the following: a float flowmeter, a thermal mass flowmeter, and a temperature transmitter.

[0029] As described above, the present application provides a diode-based segmented linearization circuit, which has the following beneficial effects: the present application uses diodes to replace the multiplexer, and only one operational amplifier is needed to realize the segmented linearization function of the sensor input signal, thereby simplifying the circuit structure and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A specific connection diagram of a diode-based piecewise linearization circuit provided in an embodiment of the present application;

[0031] Figure 2 A schematic diagram of a time and voltage curve of a sensor input signal provided in an embodiment of the present application;

[0032] Figure 3 A schematic diagram of a piecewise linearization result provided in an embodiment of the present application;

[0033] Figure 4A principle block diagram of a diode-based piecewise linearization circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0035] It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the present application in a schematic manner, and therefore the drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0036] In an exemplary embodiment, the present embodiment provides a diode-based piecewise linearization circuit, comprising:

[0037] An operational amplifier, a first circuit and a second circuit connected to the inverting input terminal of the operational amplifier; a resistor is provided between the inverting input terminal and the output terminal of the operational amplifier, and the non-inverting input terminal of the operational amplifier is connected to the sensor. As an example, in this embodiment or other embodiments, the operational amplifier is connected to the sensor to perform linear correction on the sensor input signal. In this embodiment or other embodiments, the sensor includes but is not limited to: a float flowmeter, a thermal mass flowmeter, a temperature transmitter, etc.

[0038] Wherein, the first circuit and the second circuit both include a resistor, a diode and a voltage source; in the first circuit, one end of the resistor in the first circuit is connected to the inverting input terminal of the operational amplifier, the other end corresponding to the resistor is connected to the positive electrode of the diode in the first circuit, and the negative electrode of the diode is connected to the positive electrode of the voltage source in the first circuit, and the negative electrode of the voltage source is grounded. In the second circuit, one end of the resistor in the second circuit is connected to the inverting input terminal of the operational amplifier, the other end corresponding to the resistor is connected to the negative electrode of the diode in the second circuit, and the positive electrode of the diode is connected to the positive electrode of the voltage source in the second circuit, and the negative electrode of the voltage source is grounded. In this embodiment or other embodiments, the positive electrode of each diode in the first circuit is only connected to one resistor, and the negative electrode of the diode is only connected to the positive electrode of one voltage source. In this embodiment or other embodiments, the negative electrode of each diode in the second circuit is only connected to one resistor, and the positive electrode of the diode is only connected to the positive electrode of one voltage source.

[0039] Figure 1 FIG. 1 shows a specific connection diagram of a diode-based segmented linearization circuit. Figure 1 As shown, specifically, the circuit connections inside the first circuit are:

[0040] One end of the first resistor R278 is connected to the inverting input terminal of the operational amplifier U35, the other end of the first resistor R278 is connected to the anode of the first diode D16, and the cathode of the first diode D16 is connected to the anode of the first voltage source V34, and the cathode of the first voltage source V34 is grounded.

[0041] One end of the second resistor R280 is connected to the inverting input terminal of the operational amplifier U35, the other end of the second resistor R280 is connected to the anode of the second diode D15, and the cathode of the second diode D15 is connected to the anode of the second voltage source V33, and the cathode of the second voltage source V33 is grounded.

[0042] One end of the third resistor R282 is connected to the inverting input terminal of the operational amplifier U35, the other end of the third resistor R282 is connected to the anode of the third diode D14, and the cathode of the third diode D14 is connected to the anode of the third voltage source V32, and the cathode of the third voltage source V32 is grounded.

[0043] One end of the fourth resistor R284 is connected to the inverting input terminal of the operational amplifier U35, the other end of the fourth resistor R284 is connected to the anode of the fourth diode D13, and the cathode of the fourth diode D13 is connected to the anode of the fourth voltage source V31, and the cathode of the fourth voltage source V31 is grounded.

[0044] The circuit connections inside the second circuit are:

[0045] One end of the fifth resistor R295 is connected to the inverting input terminal of the operational amplifier U35, the other end of the fifth resistor R295 is connected to the cathode of the fifth diode D9, and the anode of the fifth diode D9 is connected to the anode of the fifth voltage source V30, and the cathode of the fifth voltage source V30 is grounded.

[0046] One end of the sixth resistor R297 is connected to the inverting input terminal of the operational amplifier U35, the other end of the sixth resistor R297 is connected to the cathode of the sixth diode D8, and the anode of the sixth diode D8 is connected to the anode of the sixth voltage source V29, and the cathode of the sixth voltage source V29 is grounded.

[0047] One end of the seventh resistor R299 is connected to the inverting input terminal of the operational amplifier U35, the other end of the seventh resistor R299 is connected to the cathode of the seventh diode D7, and the anode of the seventh diode D7 is connected to the anode of the seventh voltage source V28, and the cathode of the seventh voltage source V28 is grounded.

[0048] One end of the eighth resistor R301 is connected to the inverting input terminal of the operational amplifier U35, the other end of the eighth resistor R301 is connected to the cathode of the eighth diode D6, and the anode of the eighth diode D6 is connected to the anode of the eighth voltage source V27, and the cathode of the eighth voltage source V27 is grounded.

[0049] In addition, if Figure 1 As shown, a resistor R289 is provided between the inverting input terminal and the output terminal of the operational amplifier U35. Meanwhile, in this embodiment, the voltage corresponding to the sensor input signal connected to the non-inverting input terminal of the operational amplifier U35 can be recorded as VINA, and the output voltage of the operational amplifier U35 can be recorded as VOUTA.

[0050] exist Figure 1 In the embodiment, the inverting input terminal of the operational amplifier U35 is connected to the first circuit and the second circuit. According to the voltage corresponding to the sensor input signal, the resistance in the first circuit, the resistance in the second circuit, and the resistance between the inverting input terminal and the output terminal of the operational amplifier U35 jointly form gains of different intervals. The gain is used to perform linear correction on the sensor input signal.

[0051] According to the above records, in an exemplary embodiment, the voltage source in the first circuit and the voltage source in the second circuit are respectively located in different voltage intervals. In this embodiment, the segmented voltage interval can be set by the eighth voltage source V27, the seventh voltage source V28, the sixth voltage source V29, the fifth voltage source V30, the fourth voltage source V31, the third voltage source V32, the second voltage source V33 and the first voltage source V34. Specifically, the eighth voltage source V27, the seventh voltage source V28, the sixth voltage source V29 and the fifth voltage source V30 can be set in the first voltage interval; the fourth voltage source V31, the third voltage source V32, the second voltage source V33 and the first voltage source V34 can be set in the second voltage interval. Among them, the minimum voltage of the second voltage interval is greater than the maximum voltage of the first voltage interval. As an example, in this embodiment, the first voltage interval includes the voltage interval corresponding to the sensor input signal at 0ms-15ms; the second voltage interval includes the voltage interval corresponding to the sensor input signal at 30ms-45ms. The voltages corresponding to the eighth voltage source V27, the seventh voltage source V28, the sixth voltage source V29 and the fifth voltage source V30 are in the voltage interval corresponding to 0ms-15ms of the sensor input signal; the voltages corresponding to the fourth voltage source V31, the third voltage source V32, the second voltage source V33 and the first voltage source V34 are in the voltage interval corresponding to 30ms-45ms of the sensor input signal. Figure 1 In the embodiment, the first diode D16, the second diode D15, the third diode D14, the fourth diode D13, the fifth diode D9, the sixth diode D8, the seventh diode D7 and the eighth diode D6 start to conduct only after the voltage source connected to these diodes reaches the corresponding segmented voltage interval.

[0052] Figure 2 FIG. 1 is a schematic diagram of a time-voltage curve of a sensor input signal provided by an embodiment. Figure 2 As shown in the figure, the linearity of the sensor input signal in the 0ms-15ms and 30ms-45ms intervals is poor, while the linearity in the 15-30ms interval is good. Therefore, in order to correct this curve, it is necessary to perform piecewise linearization correction in the 0ms-15ms and 30ms-45ms intervals. In the 0ms-45ms interval, since the slope is from small to large, the gain of the piecewise linearization in the 0ms-45ms interval can be from large to small. In the 30ms-45ms interval, since the slope is from large to small, the gain of the piecewise linearization in the 30ms-45ms interval can be from large to small.

[0053] Specifically, in this embodiment, according to different input signals VINA, the resistors in the first circuit, the resistors in the second circuit, and the resistors between the inverting input terminal and the output terminal of the operational amplifier U35 together form a specific comparison table of gains Av in different intervals as shown in Table 1 below.

[0054] Table 1 Gain comparison table of sensor input signal

[0055]

[0056] According to the gains in Table 1, Figure 2 The result of piecewise linearization of the sensor input signal is as follows: Figure 3 As shown by Figure 3 It can be seen that the linearity is better after segmentation, and the linearity is slightly worse at the lowest and highest points. This is because there are fewer segments. If there are higher requirements for linearity, the number of segments can be increased.

[0057] In another exemplary embodiment of the present application, Figure 4 As shown, this embodiment also provides a diode-based piecewise linearization circuit, including:

[0058] A sensor for generating an input signal, wherein the input signal includes a nonlinear signal;

[0059] A reference voltage source, used for providing multiple reference voltages and multiple segmented voltage intervals, each segmented voltage interval including at least one reference voltage;

[0060] A gain selection circuit is connected to the reference voltage source and is used to select a gain according to a comparison result between a voltage corresponding to an input signal and a segmented voltage interval;

[0061] An operational amplifier is connected to the sensor and the gain selection circuit respectively, and is used to perform linear correction on the nonlinear signal generated by the sensor according to the gain selected by the gain selection circuit; wherein the non-inverting input terminal of the operational amplifier is connected to the sensor, the inverting input terminal of the operational amplifier is connected to the gain selection circuit, and a resistor is provided between the inverting input terminal and the output terminal of the operational amplifier;

[0062] The signal output module is connected to the output end of the operational amplifier and is used to output the linearization correction result of the operational amplifier.

[0063] In this embodiment, after the reference voltage source and the gain selection circuit are connected, the first circuit and the second circuit described in other embodiments can be formed. Therefore, the specific connection relationship between the reference voltage source and the gain selection circuit refers to the first circuit and the second circuit described in other embodiments, and this embodiment will not be repeated here.

[0064] In summary, the present application provides a diode-based segmented linearization circuit, including: an operational amplifier, a first circuit connected to the inverting input terminal of the operational amplifier, and a second circuit; a resistor is arranged between the inverting input terminal and the output terminal of the operational amplifier, and the inverting input terminal of the operational amplifier is connected to the sensor; the first circuit and the second circuit both include a resistor, a diode and a voltage source; in the first circuit, one end of the resistor is connected to the inverting input terminal of the operational amplifier, the other end corresponding to the resistor is connected to the positive electrode of the diode, and the negative electrode of the diode is connected to the positive electrode of the voltage source, and the negative electrode of the voltage source is grounded; in the second circuit, one end of the resistor is connected to the inverting input terminal of the operational amplifier, the other end corresponding to the resistor is connected to the negative electrode of the diode, and the positive electrode of the diode is connected to the positive electrode of the voltage source, and the negative electrode of the voltage source is grounded. It can be seen from this that the present application uses a diode to replace the multiplexer, and only one operational amplifier is needed to realize the segmented linearization function of the sensor input signal, thereby simplifying the circuit structure and reducing the cost.

[0065] It should be understood that, although the terms first, second, third, etc. may be used to describe resistors, etc. in the embodiments of the present application, these resistors should not be limited to these terms. These terms are only used to distinguish resistors from each other. For example, without departing from the scope of the embodiments of the present application, a first resistor may also be referred to as a second resistor, and similarly, a second resistor may also be referred to as a first resistor.

[0066] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A diode-based piecewise linearization circuit, characterized in that: The invention comprises: an operational amplifier, a first circuit and a second circuit connected to an inverting input terminal of the operational amplifier; A resistor is provided between the inverting input terminal and the output terminal of the operational amplifier, and the non-inverting input terminal of the operational amplifier is connected to the sensor; The first circuit and the second circuit both include a resistor, a diode and a voltage source; In the first circuit, one end of the resistor is connected to the inverting input terminal of the operational amplifier, the other end of the resistor is connected to the anode of the diode, and the cathode of the diode is connected to the anode of the voltage source, and the cathode of the voltage source is grounded; In the second circuit, one end of the resistor is connected to the inverting input terminal of the operational amplifier, the other end of the resistor is connected to the cathode of the diode, and the anode of the diode is connected to the anode of the voltage source, and the cathode of the voltage source is grounded.

2. The diode-based piecewise linearization circuit according to claim 1, characterized in that: The first circuit comprises: One end of the first resistor is connected to the inverting input terminal of the operational amplifier, the other end of the first resistor is connected to the anode of the first diode, and the cathode of the first diode is connected to the anode of the first voltage source, and the cathode of the first voltage source is grounded; One end of the second resistor is connected to the inverting input terminal of the operational amplifier, the other end of the second resistor is connected to the anode of the second diode, and the cathode of the second diode is connected to the anode of the second voltage source, and the cathode of the second voltage source is grounded; One end of the third resistor is connected to the inverting input terminal of the operational amplifier, the other end of the third resistor is connected to the anode of the third diode, and the cathode of the third diode is connected to the anode of the third voltage source, and the cathode of the third voltage source is grounded; One end of the fourth resistor is connected to the inverting input terminal of the operational amplifier, the other end of the fourth resistor is connected to the anode of the fourth diode, and the cathode of the fourth diode is connected to the anode of the fourth voltage source, and the cathode of the fourth voltage source is grounded.

3. The diode-based piecewise linearization circuit according to claim 2, characterized in that: The second circuit includes: One end of a fifth resistor is connected to the inverting input terminal of the operational amplifier, the other end of the fifth resistor is connected to the cathode of a fifth diode, and the anode of the fifth diode is connected to the anode of a fifth voltage source, and the cathode of the fifth voltage source is grounded; One end of the sixth resistor is connected to the inverting input terminal of the operational amplifier, the other end of the sixth resistor is connected to the cathode of the sixth diode, and the anode of the sixth diode is connected to the anode of the sixth voltage source, and the cathode of the sixth voltage source is grounded; One end of the seventh resistor is connected to the inverting input terminal of the operational amplifier, the other end of the seventh resistor is connected to the cathode of the seventh diode, and the anode of the seventh diode is connected to the anode of the seventh voltage source, and the cathode of the seventh voltage source is grounded; One end of the eighth resistor is connected to the inverting input terminal of the operational amplifier, the other end of the eighth resistor is connected to the cathode of the eighth diode, and the anode of the eighth diode is connected to the anode of the eighth voltage source, and the cathode of the eighth voltage source is grounded.

4. The diode-based piecewise linearization circuit according to claim 3, characterized in that: The voltage source in the first circuit and the voltage source in the second circuit are respectively located in different voltage ranges.

5. The diode-based piecewise linearization circuit according to claim 4, characterized in that: The eighth voltage source, the seventh voltage source, the sixth voltage source and the fifth voltage source are located in a first voltage interval; the fourth voltage source, the third voltage source, the second voltage source and the first voltage source are located in a second voltage interval.

6. The diode-based piecewise linearization circuit according to claim 5, characterized in that: The minimum voltage of the second voltage interval is greater than the maximum voltage of the first voltage interval.

7. The diode-based piecewise linearization circuit according to claim 5 or 6, characterized in that: The first voltage interval includes a voltage interval corresponding to the sensor input signal when it is 0ms-15ms; The second voltage interval includes a voltage interval corresponding to the sensor input signal at 30ms-45ms.

8. The diode-based piecewise linearization circuit according to claim 7, characterized in that: According to the voltage corresponding to the sensor input signal, the resistance in the first circuit, the resistance in the second circuit, and the resistance between the inverting input terminal and the output terminal of the operational amplifier jointly form gains of different intervals, and the gains are used to perform linear correction on the sensor input signal.

9. The diode-based piecewise linearization circuit according to claim 8, characterized in that: The gain of the voltage interval corresponding to the sensor input signal at 0ms-15ms changes from large to small, and the gain of the voltage interval corresponding to the sensor input signal at 30ms-45ms changes from small to large.

10. The diode-based piecewise linearization circuit according to claim 1, characterized in that: The sensor includes at least one of the following: a float flowmeter, a thermal mass flowmeter, and a temperature transmitter.

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