Nanosecond low-delay low-distortion isolation transmission circuit suitable for arbitrary waveform signal

Abstract

The invention discloses a nanosecond low-delay low-distortion isolation transmission circuit suitable for any waveform signal, and relates to the technical field of signal isolation transmission. The circuit comprises a photoelectric bridge isolation transmission module, a signal input module and a signal output module, and the photoelectric bridge isolation transmission module comprises a first photoelectric coupler, a second photoelectric coupler, a first positive power supply, a first negative power supply, a second positive power supply and a second negative power supply. The first positive power supply, the light-emitting element of the first photoelectric coupler, the light-emitting element of the second photoelectric coupler and the first negative power supply are sequentially connected in series, the second positive power supply, the light-receiving element of the first photoelectric coupler, the light-receiving element of the second photoelectric coupler and the second negative power supply are sequentially connected in series, and the signal input module is connected to the series connection position of the two light-emitting elements. And the signal output module is connected to the serial connection part of the two light receiving elements, so that the purpose of performing ns-level low-delay and low-distortion high-speed isolation transmission on any waveform signal can be achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of signal isolation transmission, and particularly relates to a signal isolation and transmission technology in the technical field of photoelectric isolation transmission, and particularly provides a nanosecond-level low-delay low-distortion isolation transmission circuit suitable for arbitrary waveform signals, which can be applied to a scene requiring ns-level low-delay low-distortion isolation transmission of arbitrary waveform signals such as direct current signals, alternating current signals, digital signals or analog signals, and can be widely applied to related electronic products and devices such as data communication, audio and video signal isolation transmission, industrial control and medical detection. BACKGROUND

[0002] In modern communication, industrial control and medical detection and many other fields, there is an urgent need for high-speed and low-distortion isolation transmission of signals. Signal isolation technology is crucial for ensuring system safety, suppressing common-mode interference and realizing level conversion. With technological progress, digital signal isolation transmission technology has made significant progress in transmission rate, signal fidelity and the research and application of core isolation devices. However, in some specific application scenarios (such as the isolation transmission of audio and video analog signals), the need for direct and high-fidelity isolation transmission of analog signals still exists and cannot be replaced. Compared with the booming digital isolation technology, the development of analog signal isolation transmission technology is relatively slow, especially in achieving ultra-low transmission delay and extremely low signal distortion, with few breakthroughs.

[0003] Currently, traditional signal isolation transmission technologies mainly rely on three mainstream schemes: transformer coupling, capacitor coupling and photoelectric coupling, but they all have inherent limitations: (1) Transformer coupling isolation transmission technology and capacitor coupling isolation transmission technology are limited by their working principles, making it impossible for both technologies to directly couple and transmit direct current signals; and when transmitting low-frequency signals, their transmission efficiency will decrease significantly and may introduce significant phase distortion, which severely restricts their application in direct current and low-frequency signal processing scenarios; (2) Photoelectric coupling isolation transmission technology can transmit both alternating current and direct current signals, but its output signal usually has a large time delay and signal distortion problem, making it difficult to meet the high-fidelity and fast-response requirements of analog signal transmission.

[0004] To overcome some of the shortcomings of traditional technologies, the industry has developed a new technical solution based on a combination of transformer coupling and modulation / demodulation principles. For example, the invention patent with patent number CN202411215230.X adopts this technical approach, and companies have already launched isolated transmission chips based on the aforementioned principles, such as Analog Devices' ADuM series (specific models include ADuM1200). This technology offers improvements in transmission rate and signal distortion control compared to traditional solutions, possessing advantages such as higher transmission rates and lower output signal distortion. However, because its demodulation circuit typically includes an RC filter, the signal transmission delay is at least on the millisecond (ms) level, making it difficult to meet the requirements of ultra-low latency applications; simultaneously, its modulator section may introduce high-frequency interference.

[0005] In summary, the above analysis shows that optocoupler-based isolation transmission technology has become one of the mainstream solutions for digital signal isolation transmission due to its advantages such as high transmission rate, wide bandwidth, and strong anti-interference capability. However, reports of technologies or patents applying optocoupler-based isolation transmission technology to analog signal isolation transmission (especially in the pursuit of nanosecond-level ultra-low latency and low distortion high-fidelity isolation transmission) are extremely rare. Therefore, if the existing technological bottlenecks can be overcome, and optocoupler-based isolation technology can be used to achieve nanosecond-level low-latency and low-distortion high-fidelity isolation transmission of DC signals, AC signals, digital signals, or arbitrary waveform analog signals, it will mark an important development direction for optocoupler-based isolation technology. This will not only greatly broaden its application scope but may also provide innovative solutions to some long-standing technical problems. Summary of the Invention

[0006] The purpose of this invention is to provide a nanosecond-level low-delay, low-distortion isolation transmission circuit suitable for arbitrary waveform signals, in order to solve the problem that existing optocoupler isolation transmission technology is unable to perform high-fidelity isolation transmission of arbitrary waveform signals such as DC signals, AC signals, digital signals and analog signals with nanosecond-level low delay and low distortion.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a nanosecond-level low-delay, low-distortion isolated transmission circuit suitable for arbitrary waveform signals, comprising an opto-bridge isolated transmission module, a signal input module, and a signal output module. The opto-bridge isolated transmission module includes a first optocoupler, a second optocoupler, a first positive power supply, a first negative power supply, a second positive power supply, and a second negative power supply. The first optocoupler and the second optocoupler have the same model number. The output voltage of the first positive power supply and the output voltage of the first negative power supply have the same amplitude but opposite polarities. The output voltage of the second positive power supply and the output voltage of the second negative power supply have the same amplitude but opposite polarities. The first positive power supply, the light-emitting element of the first optocoupler, the light-emitting element of the second optocoupler, and the first negative power supply are connected in series in sequence; the second positive power supply, the light-receiving element of the first optocoupler, the light-receiving element of the second optocoupler, and the second negative power supply are connected in series in sequence in sequence. The signal input module is used to input arbitrary waveform signals and is connected to the series connection between the light-emitting elements of the first optocoupler and the light-emitting elements of the second optocoupler. The signal output module is connected to the series connection between the light-receiving elements of the first optocoupler and the light-receiving elements of the second optocoupler.

[0008] Based on the above-mentioned invention, a novel opto-bridge circuit topology for achieving isolated transmission of arbitrary waveform signals based on dual optocouplers is provided. This topology includes an opto-bridge isolated transmission module, a signal input module, and a signal output module. The opto-bridge isolated transmission module comprises a first optocoupler, a second optocoupler, a first positive power supply, a first negative power supply, a second positive power supply, and a second negative power supply. The first positive power supply, the light-emitting element of the first optocoupler, the light-emitting element of the second optocoupler, and the first negative power supply are connected in series. The second positive power supply, the light-receiving element of the first optocoupler, the light-receiving element of the second optocoupler, and the second negative power supply are also connected in series. The signal input module is connected at the series connection of the two light-emitting elements, and the signal output module is connected at the series connection of the two light-receiving elements. Because the output signal is generated by the two light-receiving elements, the signal transmission rate is greatly increased, i.e., the signal transmission delay is greatly reduced (achieving nanosecond-level delay). Simultaneously, the signal distortion is also greatly reduced. This enables high-speed isolated transmission of arbitrary waveform signals such as DC signals, AC signals, digital signals, or analog signals with nanosecond-level low delay and low distortion, facilitating practical application and promotion.

[0009] In one possible design, the opto-bridge isolated transmission module further includes a potentiometer, wherein the two fixed terminals of the potentiometer are respectively connected to the light-emitting elements of the first optocoupler and the second optocoupler, and the sliding terminal of the potentiometer is connected to the signal input module so that the signal input module is connected at the series connection point of the light-emitting elements of the first optocoupler and the second optocoupler.

[0010] In one possible design, the opto-bridge isolated transmission module further includes a first resistor, wherein one end of the first resistor is also connected to the series connection between the light-receiving element of the first optocoupler and the light-receiving element of the second optocoupler, and the other end of the first resistor is grounded.

[0011] In one possible design, the light-emitting elements of the first optocoupler and the second optocoupler are respectively light-emitting diodes; And / or, the light-receiving element of the first optocoupler and the light-receiving element of the second optocoupler are respectively a photodiode, a phototransistor or a photoresistor.

[0012] In one possible design, the first positive power supply includes a first DC power supply, a second resistor, a first electrolytic capacitor, a third resistor, a fourth resistor, a first three-terminal regulator, and a first capacitor, wherein the first DC power supply is used to output a first positive DC voltage. The first DC power supply is connected to one end of the second resistor. The other end of the second resistor serves as the voltage output terminal of the first positive power supply and is connected to the positive terminal of the first electrolytic capacitor, one end of the third resistor, the cathode of the first three-terminal voltage regulator, and one end of the first capacitor, respectively. The other end of the third resistor is connected to one end of the fourth resistor and the reference voltage terminal of the first three-terminal voltage regulator, respectively. The negative terminal of the first electrolytic capacitor, the other end of the fourth resistor, the positive terminal of the first three-terminal voltage regulator, and the other end of the first capacitor are grounded, respectively.

[0013] In one possible design, the second positive power supply includes a second DC power supply, a fifth resistor, a second electrolytic capacitor, a second three-terminal regulator, and a second capacitor, wherein the second DC power supply is used to output a second positive DC voltage; The second DC power supply is connected to one end of the fifth resistor. The other end of the fifth resistor serves as the voltage output terminal of the second positive power supply and is connected to the positive terminal of the second electrolytic capacitor, the reference voltage terminal of the second three-terminal regulator, the cathode of the second three-terminal regulator, and one end of the second capacitor, respectively. The negative terminal of the second electrolytic capacitor, the anode of the second three-terminal regulator, and the other end of the second capacitor are grounded, respectively.

[0014] In one possible design, the signal input module includes an input voltage divider and limiter unit and an emitter follower unit connected in sequence, wherein the input voltage divider and limiter unit is used to divide and limit the peak value of the input signal, and the emitter follower unit is used to amplify the current of the input signal.

[0015] In one possible design, the input voltage divider and limiting unit includes a two-terminal interface, a sixth resistor, and a seventh resistor, wherein the two-terminal interface is used to input arbitrary waveform signals; One end of the dual-ended interface is connected to one end of the sixth resistor, and the other end of the sixth resistor is connected to one end of the seventh resistor and the emitter follower unit, respectively. The other end of the dual-ended interface and the other end of the seventh resistor are respectively grounded.

[0016] In one possible design, the emitter follower unit includes a first operational amplifier, wherein the positive input terminal of the first operational amplifier is connected to the input voltage divider and limiting unit, the negative input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier, and the output terminal of the first operational amplifier is connected at the series connection point of the light-emitting element of the first optocoupler and the light-emitting element of the second optocoupler.

[0017] In one possible design, the signal output module includes a non-inverting amplifier unit or an inverting amplifier unit built on the basis of a second operational amplifier.

[0018] The beneficial effects of the above scheme are: (1) This invention provides a novel opto-bridge circuit topology scheme for achieving isolated transmission of arbitrary waveform signals based on dual optocouplers, which includes an opto-bridge isolated transmission module, a signal input module and a signal output module. The opto-bridge isolated transmission module includes a first optocoupler, a second optocoupler, a first positive power supply, a first negative power supply, a second positive power supply and a second negative power supply. The first positive power supply, the light-emitting element of the first optocoupler, the light-emitting element of the second optocoupler and the first negative power supply are connected in series. The second positive power supply, the light-receiving element of the first optocoupler, the light-receiving element of the second optocoupler and the second negative power supply are connected in series. The signal input module is connected at the series connection of the two light-emitting elements and the signal output module is connected at the series connection of the two light-receiving elements. Since the output signal is output by the two light-receiving elements, the signal transmission rate can be greatly improved, that is, the signal transmission delay can be greatly reduced (achieving ns-level delay). At the same time, the signal distortion is also greatly reduced, thereby achieving the purpose of high-speed isolated transmission of arbitrary waveform signals such as DC signals, AC signals, digital signals or analog signals with low delay and low distortion at the ns level. (2) The entire circuit is made of hardware, which is simple and reliable. It does not require a modem or software, making it easy to apply and promote. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a nanosecond-level low-delay, low-distortion isolated transmission circuit suitable for arbitrary waveform signals, provided in an embodiment of the present invention.

[0021] Figure 2 The following is a detailed circuit diagram of the optoelectronic bridge isolation transmission module in a nanosecond-level low-latency, low-distortion isolation transmission circuit provided in an embodiment of the present invention.

[0022] Figure 3 The following is a detailed circuit diagram of the signal input module in a nanosecond-level low-latency, low-distortion isolated transmission circuit provided in an embodiment of the present invention.

[0023] Figure 4 The present invention provides a specific circuit diagram of the signal output module in a nanosecond-level low-latency, low-distortion isolated transmission circuit.

[0024] Figure 5 This is an example diagram illustrating the delay simulation results of the output waveform signal and the input waveform signal when the input waveform signal is a rectangular wave signal, as provided in an embodiment of the present invention.

[0025] Figure 6 This is an example diagram illustrating the delay simulation results of the output waveform signal and the input waveform signal when the input waveform signal is a sine wave signal, as provided in an embodiment of the present invention. Detailed Implementation

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be briefly introduced below in conjunction with the accompanying drawings and descriptions of the embodiments or the prior art. Obviously, the following description of the structure of the accompanying drawings is only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these embodiments without creative effort. It should be noted that the description of these embodiments is for the purpose of helping to understand the present invention, but does not constitute a limitation of the present invention.

[0027] It should be understood that although the terms "first" and "second", etc., may be used herein to describe various objects, these objects should not be limited by these terms. These terms are only used to distinguish one object from another. For example, the first object may be referred to as the second object, and similarly, the second object may be referred to as the first object, without departing from the scope of the exemplary embodiments of the invention.

[0028] It should be understood that the term "and / or" that may appear in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, or A and B exist simultaneously. Another example is A, B and / or C, which can mean that any one of A, B, and C or any combination thereof exists. The term " / and" that may appear in this document describes another relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone or A and B exist simultaneously. In addition, the character " / " that may appear in this document generally indicates that the related objects before and after it are in an "or" relationship.

[0029] Example like Figures 1-6 As shown, the nanosecond-level low-latency, low-distortion isolated transmission circuit suitable for arbitrary waveform signals provided in this embodiment includes, but is not limited to, an opto-bridge isolated transmission module, a signal input module, and a signal output module. The opto-bridge isolated transmission module includes, but is not limited to, a first optocoupler (i.e.,...) Figure 2 U3 in the middle), the second optocoupler (i.e. Figure 2 U7 in the middle), the first positive power supply (i.e. Figure 2 +V1), the first negative power supply (i.e. Figure 2 -V1), the second positive power supply (i.e. Figure 2 +V2) and the second negative power supply (i.e. Figure 2 The first optocoupler has the same model number as the second optocoupler. The output voltage of the first positive power supply has the same amplitude and opposite polarity as the output voltage of the first negative power supply. The output voltage of the second positive power supply has the same amplitude and opposite polarity as the output voltage of the second negative power supply. The first positive power supply, the light-emitting element of the first optocoupler, the light-emitting element of the second optocoupler, and the first negative power supply are connected in series. The second positive power supply, the light-receiving element of the first optocoupler, the light-receiving element of the second optocoupler, and the second negative power supply are connected in series. The signal input module is used to input arbitrary waveform signals and is connected at the series connection of the light-emitting elements of the first optocoupler and the second optocoupler. The signal output module is connected at the series connection of the light-receiving elements of the first optocoupler and the second optocoupler.

[0030] like Figures 1-2As shown, in the specific structure of the nanosecond-level low-latency, low-distortion isolated transmission circuit, the signal input module, the opto-bridge isolated transmission module, and the signal output module are connected in sequence. The signal input module is used to input arbitrary waveform signals such as DC signals, AC signals, digital signals, or analog signals. The opto-bridge isolated transmission module is used to realize nanosecond-level low-latency, low-distortion isolated transmission of the arbitrary waveform signal. The signal output module is used to output the opto-isolated output signal of the arbitrary waveform signal.

[0031] The opto-bridge isolated transmission module is specifically based on an H-type bridge circuit topology (i.e., an H-type opto-bridge) composed of the first optocoupler and the second optocoupler. Its working principle is as follows: When the voltage of the arbitrary waveform signal is zero (i.e., the level at input terminal IO1 is zero), due to the H-type bridge circuit topology and as... Figure 2 The upper and lower bridge arms shown are symmetrical, and the voltage of the output signal is also zero (i.e., the level at the output terminal IO2 is also zero); when the voltage of the arbitrary waveform signal is greater than zero (i.e., the level at the input terminal IO1 is higher than zero), the light-emitting element of the first optocoupler (such as...) Figure 2 As shown, specifically the light-emitting diode (LED), the light emission will decrease due to the decrease in voltage drop, causing the light-receiving element (such as...) of the first optocoupler to... Figure 2 As shown, specifically a photodiode, the internal resistance increases, and simultaneously the light-emitting element of the second optocoupler (such as...) Figure 2 As shown, specifically a light-emitting diode (LED), the increased voltage drop will lead to an increase in the amount of light emitted, causing the light-receiving element of the second optocoupler (such as...) to... Figure 2As shown, specifically a photodiode, the internal resistance decreases, and under the combined effect of the two aforementioned factors, the voltage of the output signal drops to a negative voltage output (i.e., the level at the output terminal IO2 is below zero); when the voltage of the arbitrary waveform signal is less than zero (i.e., the level at the input terminal IO1 is below zero), the light-emitting element of the first optocoupler will increase the amount of light emitted due to the increased voltage drop, thus reducing the internal resistance of the light-receiving element of the first optocoupler. At the same time, the light-emitting element of the second optocoupler will decrease the amount of light emitted due to the decreased voltage drop, thus increasing the internal resistance of the light-receiving element of the second optocoupler. Under the combined effect of the two aforementioned factors, the voltage of the output signal rises to a positive voltage output (i.e., the level at the output terminal IO2 is above zero). Therefore, the innovative design of the H-type bridge circuit topology mentioned above has the following advantages: (1) Since the output signal is output by two light-receiving elements, the signal transmission rate will be greatly improved, that is, the signal transmission delay will be greatly reduced (achieving ns-level delay), and the signal distortion will also be greatly reduced; (2) It can realize single-ended input of input signal and single-ended output of output signal; (3) The optoelectronic bridge of the new topology can realize high-fidelity isolated transmission of arbitrary waveform signals such as DC signal, AC signal, analog signal or digital signal.

[0032] Preferably, the opto-bridge isolation transmission module further includes, but is not limited to, a potentiometer (i.e., Figure 2 In the example R8), the two fixed terminals of the potentiometer are respectively connected to the light-emitting elements of the first optocoupler and the second optocoupler, and the sliding terminal of the potentiometer is connected to the signal input module so that the signal input module is connected at the series connection point of the light-emitting elements of the first optocoupler and the second optocoupler. Figure 2 As shown, the potentiometer R8 is equivalent to a sliding resistor and serves two functions: first, as a current-limiting resistor for the two light-emitting elements; second, when the voltage of the arbitrary waveform signal is zero, the potentiometer can be adjusted to make the voltage of the output signal also zero. That is, before using the entire circuit, the potentiometer is first adjusted to the middle position, and then the voltages of the first positive power supply +V1 and the first negative power supply -V1 are adjusted respectively to make the current of the light-emitting elements on the input side of the first optocoupler and the second optocoupler about 15mA. Then, when the entire circuit is used and the voltage of the arbitrary waveform signal is zero, the voltage of the output signal is also made zero by fine-tuning the potentiometer, thereby ensuring the symmetrical balance of the H-bridge circuit topology.

[0033] Preferably, the optoelectronic bridge isolation transmission module further includes, but is not limited to, a first resistor (i.e., Figure 2In the example R9), one end of the first resistor is also connected to the series connection between the light-receiving element of the first optocoupler and the light-receiving element of the second optocoupler, and the other end of the first resistor is grounded. Figure 2 As shown, the first resistor serves as a current-limiting resistor for the two light-receiving elements and also ensures the symmetrical balance of the H-bridge circuit topology.

[0034] Preferably, the light-emitting elements of the first optocoupler and the second optocoupler are respectively light-emitting diodes; and the light-receiving elements of the first optocoupler and the second optocoupler are respectively simultaneously photodiodes, phototransistors, or photoresistors. Figure 2 As shown, the two light-emitting elements mentioned above are exemplified by light-emitting diodes, and the two light-receiving elements mentioned above are exemplified by photodiodes.

[0035] Preferably, the first positive power source includes, but is not limited to, a first DC power source (i.e., Figure 2 VCC in the middle), the second resistor (i.e. Figure 2 R5 in the middle), the first electrolytic capacitor (i.e. Figure 2 C3 in the middle), the third resistor (i.e. Figure 2 R6 in the middle), the fourth resistor (i.e. Figure 2 R7 in the middle), the first three-terminal regulator (i.e. Figure 2 U2) and the first capacitor (i.e. Figure 2 In the example, C4), the first DC power supply is used to output a first positive DC voltage; the first DC power supply is connected to one end of the second resistor, the other end of the second resistor serves as the voltage output terminal of the first positive power supply, and is respectively connected to the positive terminal of the first electrolytic capacitor, one end of the third resistor, the cathode of the first three-terminal regulator, and one end of the first capacitor; the other end of the third resistor is respectively connected to one end of the fourth resistor and the reference voltage terminal of the first three-terminal regulator; the negative terminal of the first electrolytic capacitor, the other end of the fourth resistor, the positive terminal of the first three-terminal regulator, and the other end of the first capacitor are respectively grounded. Figure 2 As shown, the first positive DC voltage is, for example, 5V. Through the specific design of the aforementioned power supply circuit structure, a stable positive voltage can be provided to the input bridge (i.e., the input terminal of the H-type bridge circuit topology), thereby ensuring the stable and reliable operation of the opto-bridge. Furthermore, the specific circuit structure of the first negative power supply needs to be consistent with the first positive power supply to ensure the symmetrical balance of the H-type bridge circuit topology, such as... Figure 2 As shown, it will not be elaborated further here.

[0036] Preferably, the second positive power source includes, but is not limited to, a second DC power source (i.e., Figure 2VDC1 in the middle), the fifth resistor (i.e. Figure 2 R4 in the middle), the second electrolytic capacitor (i.e. Figure 2 C6 in the middle), the second three-terminal regulator (i.e. Figure 2 U4 in the middle) and the second capacitor (i.e. Figure 3 In the example, C5), the second DC power supply is used to output a second positive DC voltage; the second DC power supply is connected to one end of the fifth resistor, and the other end of the fifth resistor serves as the voltage output terminal of the second positive power supply, and is respectively connected to the positive terminal of the second electrolytic capacitor, the reference voltage terminal of the second three-terminal regulator, the cathode of the second three-terminal regulator, and one end of the second capacitor; the negative terminal of the second electrolytic capacitor, the anode of the second three-terminal regulator, and the other end of the second capacitor are respectively grounded. Figure 3 As shown, the second positive DC voltage is, for example, 5V. Through the specific design of the aforementioned power supply circuit structure, a stable positive voltage can be provided to the output bridge (i.e., the output terminal of the H-type bridge circuit topology), thereby ensuring the stable and reliable operation of the opto-bridge. Furthermore, the specific circuit structure of the second negative power supply needs to be consistent with the second positive power supply to ensure the symmetrical balance of the H-type bridge circuit topology, such as... Figure 3 As shown, it will not be elaborated further here.

[0037] Preferably, the signal input module includes, but is not limited to, an input voltage divider and limiter unit and an emitter follower unit connected in sequence. The input voltage divider and limiter unit is used to divide and limit the peak value of the input signal, and the emitter follower unit is used to amplify the current of the input signal. The function of the input voltage divider and limiter unit is to divide and limit the peak value of the input signal to prevent the opto-bridge components in the opto-bridge isolation transmission module from burning out due to overload or causing output signal distortion caused by an excessively large input signal; for example... Figure 3 As shown, the input voltage divider and limiting unit specifically includes, but is not limited to, having a dual-ended interface (i.e., Figure 3 J2 in the middle), the sixth resistor (i.e. Figure 3 R14 in the middle) and the seventh resistor (i.e. Figure 4 In the example, R15), the dual-ended interface is used to input arbitrary waveform signals; one end of the dual-ended interface is connected to one end of the sixth resistor, the other end of the sixth resistor is connected to one end of the seventh resistor and the emitter follower unit, and the other end of the dual-ended interface and the other end of the seventh resistor are grounded. The function of the emitter follower unit is to ensure that the signal input module has sufficient power to drive the opto-bridge element in the opto-bridge isolation transmission module; such as... Figure 4 As shown, the emitter follower unit includes, but is not limited to, a first operational amplifier (i.e., Figure 5In the U8A (etc.), the positive input terminal of the first operational amplifier is connected to the input voltage divider and limiting unit, the negative input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier, and the output terminal of the first operational amplifier is connected in series between the light-emitting element of the first optocoupler and the light-emitting element of the second optocoupler. Through the specific circuit structure design of the aforementioned signal input module, the arbitrary waveform signal can be input from the dual-ended interface, and after being voltage divided and limited by the sixth resistor and the seventh resistor, the input signal is sent to the first operational amplifier for current amplification, and finally output from port IO1 to drive the subsequent circuit. Furthermore, the voltage of the arbitrary waveform signal must be less than or equal to 2.2 × Vp-p (where Vp-p represents the peak-to-peak voltage of the first optocoupler and the second optocoupler) to avoid overloading of the subsequent circuit. That is, under the condition that the voltage of the arbitrary waveform signal is less than or equal to 2.2 × Vp-p, the maximum / minimum current of the LEDs on the input side of the first optocoupler and the second optocoupler varies between 5mA and 25mA to ensure that the LEDs do not experience overcurrent, thereby ensuring that the first optocoupler and the second optocoupler can operate reliably for a long time.

[0038] Preferably, the signal output module includes, but is not limited to, a second operational amplifier (i.e., Figure 6 The U1A in the diagram can be used to construct a non-inverting or inverting amplifier unit. The design function of the non-inverting or inverting amplifier unit is to amplify the output signal to drive subsequent circuits. The specific circuit structure is as follows: Figure 5 As shown.

[0039] Regarding the aforementioned nanosecond-level low-latency, low-distortion isolated transmission circuit, this embodiment also uses Multisim software to conduct simulation experiments on the circuit with rectangular wave signals and sine wave signals as input waveform signals, respectively. The experimental results are as follows: Figure 6 and ​ As shown: (1) In the case of ​ In the simulation waveform diagram shown, the upper part is the rectangular wave signal at the input end, and the lower part is the rectangular wave signal at the output end (this output waveform signal has been inverted). The phase of the rising edge of the two rectangular wave signals was measured by two cursors, and the phase difference was found to be 468.933ns. That is, the output waveform signal is delayed by 468.933ns compared with the input waveform signal, which proves that the ns-level delay has been achieved. According to the waveform comparison results, the distortion is also very small (generally speaking, the shorter the delay, the smaller the distortion, and vice versa). (2) In the case of ​The simulation waveform diagram shown shows the input sine wave signal at the top and the output sine wave signal at the bottom (this output waveform signal has been inverted). The phase of the upper peak values ​​of these two sine wave signals was measured using two cursors, and the phase difference was found to be 586.166ns. This means that the output waveform signal is delayed by 586.166ns compared to the input waveform signal, which also proves that a delay at the nanosecond level has been achieved. Furthermore, the waveform comparison results show that the distortion is also extremely small.

[0040] In summary, the nanosecond-level low-latency, low-distortion isolation transmission circuit provided in this embodiment has the following technical advantages: (1) This embodiment provides a novel opto-bridge circuit topology scheme for achieving isolated transmission of arbitrary waveform signals based on dual optocouplers, which includes an opto-bridge isolated transmission module, a signal input module and a signal output module. The opto-bridge isolated transmission module includes a first optocoupler, a second optocoupler, a first positive power supply, a first negative power supply, a second positive power supply and a second negative power supply. The first positive power supply, the light-emitting element of the first optocoupler, the light-emitting element of the second optocoupler and the first negative power supply are connected in series. The second positive power supply, the light-receiving element of the first optocoupler, the light-receiving element of the second optocoupler and the second negative power supply are connected in series. The signal input module is connected at the series connection of the two light-emitting elements, and the signal output module is connected at the series connection of the two light-receiving elements. Since the output signal is output by the two light-receiving elements, the signal transmission rate can be greatly improved, that is, the signal transmission delay can be greatly reduced (achieving ns-level delay). At the same time, the signal distortion is also greatly reduced, thereby achieving the purpose of high-speed isolated transmission of arbitrary waveform signals such as DC signals, AC signals, digital signals or analog signals with ns-level low delay and low distortion. (2) The entire circuit is made of hardware, which is simple and reliable. It does not require a modem or software, making it easy to apply and promote.

[0041] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A nanosecond-level low-delay low-distortion isolation transmission circuit suitable for arbitrary waveform signals, characterized by, The photoelectric bridge isolation transmission module, the signal input module and the signal output module, wherein the photoelectric bridge isolation transmission module comprises a first optocoupler (U3), a second optocoupler (U7), a first positive power supply (+V1), a first negative power supply (-V1), a second positive power supply (+V2) and a second negative power supply (-V2), the first optocoupler (U3) has the same model as the second optocoupler (U7), the output voltage of the first positive power supply (+V1) has the same amplitude and opposite polarity as the output voltage of the first negative power supply (-V1), and the output voltage of the second positive power supply (+V2) has the same amplitude and opposite polarity as the output voltage of the second negative power supply (-V2); The first positive power supply (+V1), the light-emitting element of the first optocoupler (U3), the light-emitting element of the second optocoupler (U7) and the first negative power supply (-V1) are connected in series, and the second positive power supply (+V2), the light-receiving element of the first optocoupler (U3), the light-receiving element of the second optocoupler (U7) and the second negative power supply (-V2) are connected in series; The signal input module is used for inputting an arbitrary waveform signal and is connected at the series connection of the light-emitting element of the first optocoupler (U3) and the light-emitting element of the second optocoupler (U7), and the signal output module is connected at the series connection of the light-receiving element of the first optocoupler (U3) and the light-receiving element of the second optocoupler (U7).

2. The nanosecond low latency low distortion isolated transmission circuit of claim 1, wherein, The photoelectric bridge isolation transmission module further comprises a potentiometer (R8), wherein the two fixed terminals of the potentiometer (R8) are respectively and one-to-one connected to the light-emitting element of the first optocoupler (U3) and the light-emitting element of the second optocoupler (U7), and the sliding terminal of the potentiometer (R8) is connected to the signal input module to realize the connection of the signal input module at the series connection of the light-emitting element of the first optocoupler (U3) and the light-emitting element of the second optocoupler (U7).

3. The nanosecond low latency low distortion isolated transmission circuit of claim 1, wherein, The photoelectric bridge isolation transmission module further comprises a first resistor (R9), wherein one end of the first resistor (R9) is also connected at the series connection of the light-receiving element of the first optocoupler (U3) and the light-receiving element of the second optocoupler (U7), and the other end of the first resistor (R9) is grounded.

4. The nanosecond low latency low distortion isolated transmission circuit of claim 1, wherein, The light-emitting element of the first optocoupler (U3) and the light-emitting element of the second optocoupler (U7) are respectively a light-emitting diode; And / or, the light-receiving element of the first optocoupler (U3) and the light-receiving element of the second optocoupler (U7) are respectively and simultaneously a photodiode, a photosensitive triode or a photosensitive resistor.

5. The nanosecond low latency low distortion isolated transmission circuit of claim 1, wherein, The first positive power supply (+V1) comprises a first direct current power supply (VCC), a second resistor (R5), a first electrolytic capacitor (C3), a third resistor (R6), a fourth resistor (R7), a first three-terminal voltage regulator (U2) and a first capacitor (C4), wherein the first direct current power supply (VCC) is used for outputting a first positive direct current voltage; The first direct current source (VCC) is connected to one end of the second resistor (R5), the other end of the second resistor (R5) is used as the voltage output end of the first positive power supply (+V1), and is respectively connected to the positive electrode of the first electrolytic capacitor (C3), one end of the third resistor (R6), the cathode of the first three-terminal voltage regulator (U2) and one end of the first capacitor (C4), the other end of the third resistor (R6) is respectively connected to one end of the fourth resistor (R7) and the reference voltage end of the first three-terminal voltage regulator (U2), the negative electrode of the first electrolytic capacitor (C3), the other end of the fourth resistor (R7), the positive electrode of the first three-terminal voltage regulator (U2) and the other end of the first capacitor (C4) are respectively grounded.

6. The nanosecond low latency low distortion isolated transmission circuit of claim 1, wherein, The second positive power supply (+V2) comprises a second direct current source (VDC1), a fifth resistor (R4), a second electrolytic capacitor (C6), a second three-terminal voltage regulator (U4) and a second capacitor (C5), wherein the second direct current source (VDC1) is used for outputting a second positive direct current voltage; The second direct current source (VDC1) is connected to one end of the fifth resistor (R4), the other end of the fifth resistor (R4) is used as the voltage output end of the second positive power supply (+V2), and is respectively connected to the positive electrode of the second electrolytic capacitor (C6), the reference voltage end of the second three-terminal voltage regulator (U4), the cathode of the second three-terminal voltage regulator (U4) and one end of the second capacitor (C5), the negative electrode of the second electrolytic capacitor (C6), the anode of the second three-terminal voltage regulator (U4) and the other end of the second capacitor (C5) are respectively grounded.

7. The nanosecond low latency low distortion isolated transmission circuit of claim 1, wherein, The signal input module comprises an input voltage division limiting unit and an emitter follower unit connected in sequence, wherein the input voltage division limiting unit is used for voltage division limiting the peak value of an input signal, and the emitter follower unit is used for current amplification of the input signal.

8. The nanosecond low latency low distortion isolated transmission circuit of claim 7, wherein, The input voltage division limiting unit comprises a double-ended interface (J2), a sixth resistor (R14) and a seventh resistor (R15), wherein the double-ended interface (J2) is used for inputting an arbitrary waveform signal; One end of the double-ended interface (J2) is connected to one end of the sixth resistor (R14), the other end of the sixth resistor (R14) is respectively connected to one end of the seventh resistor (R15) and the emitter follower unit, and the other end of the double-ended interface (J2) and the other end of the seventh resistor (R15) are respectively grounded.

9. The nanosecond low latency low distortion isolated transmission circuit of claim 7, wherein, The emitter follower unit comprises a first operational amplifier (U8A), wherein the positive input end of the first operational amplifier (U8A) is connected to the input voltage division limiting unit, the negative input end of the first operational amplifier (U8A) is connected to the output end of the first operational amplifier (U8A), and the output end of the first operational amplifier (U8A) is connected to the series connection of the light-emitting element of the first optocoupler (U3) and the light-emitting element of the second optocoupler (U7).

10. The nanosecond low latency low distortion isolated transmission circuit of claim 1, wherein, The signal output module comprises an in-phase amplification unit or an inverse-phase amplification unit based on a second operational amplifier (U1A).

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