High-temperature-resistant communication circuit, communication method of high-temperature-resistant communication circuit and chip

Abstract

The invention provides a high-temperature-resistant communication circuit, a communication method of the high-temperature-resistant communication circuit and a chip, and belongs to the technical field of communication processing. The circuit comprises a full-bridge driving circuit which comprises a first input end, a second input end, a third input end, a fourth input end, an output end and a working end; the communication antenna is electrically connected with the output end of the full-bridge driving circuit; the communication antenna carries out communication by using a modulation mode of frequency shift keying or binary phase shift keying; the micro-processing unit is electrically connected with the first input end, the second input end, the third input end, the fourth input end and the working end respectively and used for controlling the magnitude and the time sequence of voltage signals input into the first input end, the second input end, the third input end and the fourth input end respectively, so that continuous alternating current is generated on the communication antenna; and the current is used for setting a threshold range for the working end. The high-temperature-resistant communication circuit is used for overcoming the defect that a communication circuit capable of achieving underground high-temperature resistance is lacked in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of communication processing, and particularly to a communication circuit with high temperature resistance, a communication circuit with high temperature resistance, and a chip. Background Art

[0002] In drilling operations, there are scenarios where product communication needs to be carried out underground (or underwater). General underground communication research and products pursue a large communication bandwidth, so the carrier frequencies used are generally relatively high, and complex baseband, modulation, demodulation, and other dedicated communication circuits are required. Such communication circuits usually cannot reach the operating temperature above 150°C required for underground operating environments. Moreover, due to the changes in device internal resistance and load (antenna) internal resistance brought about by a wide temperature range, ordinary power amplifier circuits cannot control the transmitted current well, easily resulting in too low transmitted current at certain temperatures, leading to a reduction in communication quality, and too high transmitted current at certain temperatures, causing the power supply to overload and restart, resulting in communication failure.

[0003] That is, the prior art lacks a communication circuit that can achieve high temperature resistance underground. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a communication circuit with high temperature resistance, a communication circuit with high temperature resistance, and a chip to solve the defect that the prior art lacks a communication circuit that can achieve high temperature resistance underground.

[0005] To achieve the above purpose, the embodiments of the present invention provide a communication circuit with high temperature resistance, including:

[0006] A full-bridge drive circuit, including a first input terminal, a second input terminal, a third input terminal, a fourth input terminal, an output terminal, and a working terminal;

[0007] A communication antenna, electrically connected to the output terminal of the full-bridge drive circuit; the communication antenna uses frequency shift keying or binary phase shift keying modulation methods for communication;

[0008] A microprocessing unit, electrically connected to the first input terminal, the second input terminal, the third input terminal, the fourth input terminal, and the working terminal respectively, for respectively controlling the magnitude and timing of the voltage signals input to the first input terminal, the second input terminal, the third input terminal, and the fourth input terminal, so as to generate continuous alternating current on the communication antenna, and for setting a threshold range of current for the working terminal.

[0009] Optionally, the microprocessing unit includes a current control circuit for providing a current with a threshold range for the working terminal, and the current control circuit includes: a seventh switching tube, a first resistor, and a precision resistor;

[0010] The control terminal of the seventh switching tube is electrically connected to the first end of the first resistor. The second end of the first resistor is electrically connected to a first set voltage source which outputs a voltage within a set threshold range. The first end of the seventh switching tube is electrically connected to the working end. The second end of the seventh switching tube is electrically connected to the first end of the precision resistor, and the second end of the precision resistor is grounded.

[0011] Optionally, the current control circuit further includes a second resistor. The first end of the second resistor is electrically connected to the control terminal of the seventh switching tube, and the second end of the second resistor is grounded.

[0012] Optionally, the voltage output by the first set voltage source within the set threshold range is from 0V to 1.1V.

[0013] Optionally, the seventh switching tube is formed by connecting multiple switching tubes in parallel.

[0014] Optionally, the high-temperature resistant communication circuit further includes a first switch control circuit electrically connected to the first input terminal. The first switch control circuit includes a third resistor, a fourth resistor, a fifth resistor, and a fifth switching tube. The first end of the third resistor is electrically connected to a second set voltage source. The second end of the third resistor is electrically connected to the control terminal of the fifth switching tube. The first end of the fourth resistor is electrically connected to a third set voltage source. The second end of the fourth resistor is electrically connected to both the first end of the fifth switching tube and the first input terminal. The first end of the fifth resistor is electrically connected to the second end of the fifth switching tube, and the second end of the fifth resistor is used to receive the voltage signal input by the microprocessing unit.

[0015] Optionally, the high-temperature resistant communication circuit further includes a second switch control circuit electrically connected to the second input terminal. The second switch control circuit includes a sixth resistor, a seventh resistor, an eighth resistor

[0016] and a sixth switching tube. The first end of the sixth resistor is electrically connected to the second set voltage source. The second end of the sixth resistor is electrically connected to the control terminal of the sixth switching tube. The first end of the seventh resistor is electrically connected to the third set voltage source. The second end of the seventh resistor is electrically connected to both the first end of the sixth switching tube and the second input terminal. The first end of the eighth resistor is electrically connected to the second end of the sixth switching tube, and the second end of the eighth resistor is used to receive the voltage signal input by the microprocessing unit.

[0017] Optionally, the fifth switching tube and the sixth switching tube are respectively a triode or a MOS tube.

[0018] Optionally, the full-bridge drive circuit includes: a first switching transistor, a second switching transistor, a third switching transistor, a fourth switching transistor, a first diode, a second diode, a third diode, and a fourth diode;

[0019] The first switching transistor and the third switching transistor are connected in series. The control terminal of the first switching transistor serves as the first input terminal. The first switching transistor and the first diode are connected in parallel. The third switching transistor and the third diode are connected in parallel. The control terminal of the third switching transistor serves as the third input terminal. The second switching transistor and the fourth switching transistor are connected in series. The control terminal of the second switching transistor serves as the second input terminal. The second switching transistor and the second diode are connected in parallel. The fourth switching transistor and the fourth diode are connected in parallel. The control terminal of the fourth switching transistor serves as the fourth input terminal. The first switching transistor pair formed by the first switching transistor and the third switching transistor is connected in parallel with the second switching transistor pair formed by the second switching transistor and the fourth switching transistor. The common terminal where the third switching transistor and the fourth switching transistor are electrically connected serves as the working terminal.

[0020] Optionally, the first diode, the second diode, the third diode, and the fourth diode are respectively selected as freewheeling diodes.

[0021] Optionally, the first switching transistor, the second switching transistor, the third switching transistor, and the fourth switching transistor are respectively selected as triodes or MOS transistors.

[0022] On the other hand, an embodiment of the present invention further provides a communication method for a high-temperature-resistant communication circuit, which is applied to the above-mentioned high-temperature-resistant communication circuit. The method includes:

[0023] Controlling the microprocessing unit to output a current within a set threshold range to the working terminal of the full-bridge drive circuit;

[0024] Controlling the magnitudes and timings of the voltage signals input by the microprocessing unit to the first input terminal, the second input terminal, the third input terminal, and the fourth input terminal of the full-bridge drive circuit, so as to generate a continuous alternating current on the communication antenna.

[0025] Optionally, the microprocessing unit includes a current control circuit for providing a current within a set threshold range to the working terminal. The current control circuit includes: a seventh switching transistor, a first resistor, and a precision resistor. The first terminal of the seventh switching transistor is electrically connected to the working terminal. The second terminal of the seventh switching transistor is electrically connected to the first terminal of the precision resistor. The current within the set threshold range is obtained through the following steps:

[0026] The control microprocessing unit respectively inputs voltage signals of different magnitudes and timings to the first input terminal, the second input terminal, the third input terminal, and the fourth input terminal of the full-bridge drive circuit, so as to generate continuous alternating current on the communication antenna;

[0027] Detect the current range at the first end of the precision resistor during the stage when continuous alternating current is generated on the communication antenna, and use this current range as the current of the set threshold range.

[0028] Optionally, the control microprocessing unit respectively inputs voltage signals of different magnitudes and timings to the first input terminal, the second input terminal, the third input terminal, and the fourth input terminal of the full-bridge drive circuit, so as to generate continuous alternating current on the communication antenna, including:

[0029] Repeat the following steps until a set end condition is obtained:

[0030] Control the microprocessing unit to input an on-voltage to the first input terminal and the fourth input terminal of the full-bridge drive circuit respectively in the first cycle, and input an off-voltage to the second input terminal and the third input terminal of the full-bridge drive circuit respectively;

[0031] Control the microprocessing unit to input an on-voltage to the fourth input terminal of the full-bridge drive circuit in the second cycle, and input an off-voltage to the first input terminal, the second input terminal, and the third input terminal of the full-bridge drive circuit respectively;

[0032] Control the microprocessing unit to input an off-voltage to the first input terminal and the fourth input terminal of the full-bridge drive circuit respectively in the third cycle, and to the second input

[0033] Control the microprocessing unit to input an on-voltage to the third input terminal of the full-bridge drive circuit in the fourth cycle, and input an off-voltage to the first input terminal, the second input terminal, and the fourth input terminal of the full-bridge drive circuit respectively.

[0034] On the other hand, an embodiment of the present invention further provides a chip, including the above-mentioned high-temperature-resistant communication circuit, a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the communication method of the above-mentioned high-temperature-resistant communication circuit.

[0035] Through the above technical solutions, in the embodiments of the present invention, the microprocessing unit controls the magnitudes and timings of the voltage signals input to the first input terminal, the second input terminal, the third input terminal, and the fourth input terminal respectively, so as to generate continuous alternating current on the communication antenna and a current for setting a threshold range for the working end. Among them, the communication antenna uses modulation methods such as frequency shift keying or binary phase shift keying for low-frequency communication. Without the need for a complex communication modulation and demodulation circuit while ensuring a certain underground use bandwidth. The embodiments of the present invention adopt discrete devices of a full-bridge drive circuit, a communication antenna, and a microprocessing unit, which have high reliability at high temperatures. And by setting a threshold range of current for the working end, the stable and reliable communication of the communication circuit within a wide temperature range is well ensured by controlling the transmission current. Thus, the communication circuit of the embodiments of the present invention achieves high temperature resistance in the underground.

[0036] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent specific implementation part. Brief Description of the Drawings

[0037] The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. Together with the following specific implementation, they are used to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the drawings:

[0038] Figure 1 is one of the schematic structural diagrams of the high-temperature-resistant communication circuit provided by the present invention;

[0039] Figure 2 is a comparison schematic diagram of various underwater wireless communication technologies provided by the present invention;

[0040] Figure 3 is a timing schematic diagram of the first output terminal S1 to the fourth output terminal S4 of the microcontrol unit of the present invention for the full-bridge drive circuit;

[0041] Figure 4 is a schematic diagram of the switching states of the first switching transistor Q1 to the fourth switching transistor Q4 provided by the present invention;

[0042] Figure 5 is a schematic diagram of the current waveform passing through the helical antenna provided by the present invention;

[0043] Figure 6 is the second schematic structural diagram of the high-temperature-resistant communication circuit provided by the present invention;

[0044] Figure 7 is the V BE and I c relationship curve schematic diagram of a typical NPN transistor provided by the present invention;

[0045] Figure 8 It is a schematic flow chart of the communication method of the high-temperature-resistant communication circuit provided by the present invention. Specific embodiments

[0046] The following will describe in detail the specific embodiments of the embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the embodiments of the present invention, and are not used to limit the embodiments of the present invention.

[0047] Circuit embodiment

[0048] Please refer to Figure 1 , the embodiment of the present invention provides a high-temperature-resistant communication circuit, including: a full-bridge drive circuit 1, a communication antenna 2, and a microprocessing unit 3.

[0049] The full-bridge drive circuit 1 includes a first input terminal, a second input terminal, a third input terminal, a fourth input terminal, an output terminal, and a working terminal. In one embodiment, the full-bridge drive circuit 1 includes: a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. The first switch tube Q1 and the third switch tube Q3 are connected in series, the control terminal of the first switch tube Q1 is used as the first input terminal, the first switch tube Q1 and the first diode D1 are connected in parallel, the third switch tube Q3 and the third diode D3 are connected in parallel, and the control terminal of the third switch tube Q3 is used as the third input terminal; the second switch tube Q2 and the fourth switch tube Q4 are connected in series, the

[0050] control terminal of the second switch tube Q2 is used as the second input terminal, the second switch tube Q2 and the second diode D2 are connected in parallel, the fourth switch tube Q4 and the fourth diode D4 are connected in parallel, and the control terminal of the fourth switch tube Q4 is used as the fourth input terminal; the first switch tube pair formed by the first switch tube Q1 and the third switch tube Q3 is connected in parallel with the second switch tube pair formed by the second switch tube Q2 and the fourth switch tube Q4; the common terminal where the third switch tube Q3 and the fourth switch tube Q4 are electrically connected is used as the working terminal.

[0051] The first switching transistor Q1, the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4 are respectively selected from bipolar transistors or MOS transistors. In one embodiment, since the use of MOS transistors results in relatively low losses at high currents, the first switching transistor Q1, the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4 are respectively selected as MOS transistors. In the embodiment of the present invention, a full-bridge drive circuit 1 is formed by the first switching transistor Q1 to the fourth switching transistor Q4. Among them, the first switching transistor Q1 and the second switching transistor Q2 are PMOS transistors, and the third switching transistor Q3 and the fourth switching transistor Q4 are NMOS transistors. The control terminals of the first switching transistor Q1, the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4 are all gates.

[0052] In the embodiment of the present invention, the full-bridge drive circuit 1 formed by the four switching transistors of the first switching transistor Q1 to the fourth switching transistor Q4 drives the middle communication antenna 2. The switching signals of the first switching transistor Q1 to the fourth switching transistor Q4 are controlled by a microcontroller unit. In one embodiment, the first diode D1, the second diode D2, the third diode D3, and the fourth diode D4 are respectively selected as freewheeling diodes. By setting the freewheeling diodes, the current in the full-bridge drive circuit 1 can change relatively smoothly, avoiding the occurrence of surge voltages. It should be noted that if the first switching transistor Q1 to the fourth switching transistor Q4 are MOS transistors with built-in protection diodes, the first diode D1 to the fourth diode D4 can be omitted.

[0053] The communication antenna 2 is electrically connected to the output terminal of the full-bridge drive circuit 1; the communication antenna 2 uses frequency shift keying or binary phase shift keying modulation methods for communication.

[0054] Currently, wireless communication is mostly used underwater, mainly including four methods: acoustic wave, visible light, electromagnetic wave, and magnetic induction communication, as Figure 2 shown. As can be seen Figure 2 from the above, in the selection of short-distance wireless communication solutions underground

[0055] magnetic induction communication is the best.

[0056] According to the theory of electrodynamics, a time-varying magnetic field generates an electric field in a conductor. When the excitation coil is located in a conductive medium such as non-pure water (such as drilling fluid), an electric field will be generated in the surrounding drilling fluid. Due to the existence of the electric field in the drilling fluid, many current loops are generated in the drilling fluid. These current loops are perpendicular to the magnetic flux of the coil, and these currents are called eddy currents. Their direction and magnitude depend on the magnetic field generated by the current flowing through the coil; the eddy currents will generate a new magnetic field underwater. According to Lenz's law, this magnetic field generates an effect that suppresses the original magnetic field, resulting in the attenuation of the magnetic field when it is far from the field source. The closer to the transmitting coil, the stronger the eddy currents, and the eddy current loss will increase with the increase of the frequency, while the decrease of the frequency will bring about a reduction in the communication bandwidth.

[0057] General magnetic induction communication research and products all pursue larger communication bandwidth, so the carrier frequency used is generally higher, requiring complex baseband, modulation, demodulation and other dedicated communication circuits. Such communication circuits usually cannot reach the operating temperature of more than 150°C required for underground working environments. And due to the above-mentioned eddy current loss problem, the communication distance of the product is very short.

[0058] However, in underground conditions, the demand for communication bandwidth is relatively low, so it is necessary to reduce the communication frequency as much as possible to reduce eddy current loss and increase the communication distance. Therefore, the communication antenna 2 of the embodiment of the present invention adopts the simplest communication method such as frequency shift keying (FSK) or binary phase shift keying (BPSK), completely getting rid of the dependence on dedicated digital signal modulation and demodulation communication circuits, and improving the reliability of underground communication equipment.

[0059] In one embodiment, the communication antenna 2 may be a helical antenna, and a typical transmission frequency may be 1 KHz.

[0060] The microprocessing unit 3 is electrically connected to the first input terminal, the second input terminal, the third input terminal, the fourth input terminal and the working terminal, respectively, and is used to control the magnitude and timing of the voltage signals input to the first input terminal, the second input terminal, the third input terminal and the fourth input terminal, respectively, so as to generate a continuous alternating current on the communication antenna 2, and to set a current within a threshold range for the working terminal. The microprocessing unit 3 includes a first output terminal S1 for outputting a voltage to the first input terminal of the full-bridge drive circuit 1, and a second output terminal S2 for outputting a current to the second input terminal of the full-bridge drive circuit 1.

[0061] A second output terminal S2 for outputting a voltage to a third input terminal of the full-bridge drive circuit 1, a third output terminal S3 for outputting a voltage to a third input terminal of the full-bridge drive circuit 1, and a fourth output terminal S4 for outputting a voltage to a fourth input terminal of the full-bridge drive circuit 1.

[0062] In one embodiment, the timing of the first output terminal S1 to the fourth output terminal S4 of the four I / O ports of the micro control unit to the full-bridge driving circuit 1 is as follows: Figure 3 As shown:

[0063] From the 0 moment, the first output terminal S1 and the third output terminal S3 output low level, and the fourth output terminal S4 and the second output terminal S2 output high level. At the 1 / 4 cycle, i.e., at the t1 moment, the output of the first output terminal S1 becomes high level, the outputs of the fourth output terminal S4 and the second output terminal S2 remain high level, and the output of the third output terminal S3 remains low level. At the half cycle, i.e., at the t2 moment, the output of the first output terminal S1 remains high level, the outputs of the fourth output terminal S4 and the second output terminal S2 become low level, and the output of the third output terminal S3 becomes high level. At the 3 / 4 cycle, i.e., at the t3 moment, the output of the first output terminal S1 remains high level, the output of the fourth output terminal S4 remains low level, the output of the second output terminal S2 becomes high level, and the output of the third output terminal S3 remains high level. At the end of the first complete cycle, i.e., at the t4 moment, the output of the first output terminal S1 remains high level, the output of the fourth output terminal S4 remains low level, the output of the second output terminal S2 remains high level, and the output of the third output terminal S3 remains high level.

[0064] Please refer to Figure 4 The switching states of the first switching transistor Q1 to the fourth switching transistor Q4 can more intuitively understand its working principle. From 0 to t1, the first switching transistor Q1 and the fourth switching transistor Q4 are turned on, and the current passes through the spiral antenna from left to right. From t1 to t2, the first switching transistor Q1 is turned off, and the fourth switching transistor Q4 remains turned on. At this time, the energy in the spiral antenna (which can be regarded as an inductor) is released through the loop of the fourth switching transistor Q4 to the third diode D3. From t2 to t3, the second switching transistor Q2 and the third switching transistor Q3 are turned on, and the current passes through the spiral antenna from right to left. From t3 to t4, the second switching transistor Q2 is turned off, and the third switching transistor Q3 remains turned on. At this time, the energy in the spiral antenna (which can be regarded as an inductor) is released through the loop of the third switching transistor Q3 to the fourth diode D4. Through the above cycle, the current waveform passing through the spiral antenna is as Figure 5 shown, and the positive current represents Figure 1 the current direction from left to right in

[0065] In addition, the microprocessing unit 3 in the embodiment of the present invention provides a voltage within a set threshold range to the working ends electrically connected to the third switching transistor Q3 and the fourth switching transistor Q4 through the DAC port, so as to set a current within the set threshold range for the working ends, and the stability and reliability of communication within a wide temperature range are well ensured by controlling the transmission current.

[0066] In the embodiment of the present invention, the microprocessing unit 3 controls the magnitudes and timings of the voltage signals input to the first input terminal, the second input terminal, the third input terminal, and the fourth input terminal respectively, so as to generate continuous alternating current on the communication antenna 2 and a current for setting a threshold range for the working end. The communication antenna 2 uses modulation methods such as frequency shift keying or binary phase shift keying for low-frequency communication. Without the need for a complex communication modulation and demodulation circuit while ensuring a certain underground usage bandwidth. The embodiment of the present invention adopts discrete devices of a full-bridge drive circuit 1, a communication antenna 2, and a microprocessing unit 3, which has high reliability at high temperatures. And by setting a threshold range of current for the working end, the stability and reliability of the communication circuit during communication within a wide temperature range are well ensured by controlling the transmission current. Thus, the communication circuit of the embodiment of the present invention realizes high-temperature resistance underground.

[0067] In other aspects of the implementation of the present invention, please refer to Figure 1 , the microprocessing unit 3 includes a current control circuit for providing a current for setting a threshold range for the working end, and the current control circuit includes: a seventh switching tube Q7, a first resistor R1, and a precision resistor Rs.

[0068] The control end of the seventh switching tube Q7 is electrically connected to the first end of the first resistor R1. The second end of the first resistor R1 is electrically connected to a first set voltage source, and the first set voltage source outputs a voltage within the set threshold range. The first end of the seventh switching tube Q7 is electrically connected to the working end. The second end of the seventh switching tube Q7 is electrically connected to the first end of the precision resistor Rs, and the second end of the precision resistor is grounded. Among them, the seventh switching tube Q7 can be selected from MOS tubes or triodes. In the embodiment of the present invention, the seventh switching tube Q7 is selected as a triode. The control end of the seventh switching tube Q7 is the base, the first end of the seventh switching tube Q7 is the collector, and the second end of the seventh switching tube Q7 is the emitter.

[0069] In other aspects of the implementation of the present invention, please refer to Figure 6 , the current control circuit further includes a second resistor R2. The first end of the second resistor R2 is electrically connected to the control end of the seventh switching tube Q7, and the second end of the second resistor R2 is grounded. The current control circuit can be simplified to have no second resistor R2 and only retain the first resistor R1, that is, the DAC port directly controls the current of the seventh switching tube Q7. This simplified solution is applicable when the resolution of the DAC port is high.

[0070] The ADC port, DAC port, precision resistor Rs, seventh switching transistor Q7 built into the microcontroller unit of the embodiment of the present invention, as well as the first resistor R1 and the second resistor R2 together constitute a current control circuit. The DAC port outputs a first set voltage source. Among them, the precision resistor Rs is a precision resistor with an extremely low temperature coefficient, ensuring that its resistance value changes very little in a wide temperature range, especially at high temperatures. Its resistance value is generally selected as 0.1 ohm. Each time before the communication is officially started, the full-bridge drive circuit 1 is controlled to operate for several cycles first. The microcontroller unit can determine the output value of the DAC port by detecting the peak current of the circuit in these several cycles, and thus can accurately control the current.

[0071] The circuit controls the current of the seventh switching transistor Q7, that is, the main circuit of the circuit, through the output of the DAC port. Figure 7 For the V of a typical NPN transistor BE and I c relationship curve, the purpose of controlling Ic can be achieved by accurately controlling the voltage of the DAC port. However, due to the small control range, in the embodiment of the present invention, a simple resistor network of the first resistor R1 and the second resistor R2 (Vcc = 3.3V, the ratio of the first resistor R1 to the second resistor R2 is about 2:1. For example, the first resistor R1 is taken as 2 kΩ and the second resistor R2 is taken as 1 kΩ) is adopted to control the control range of the DAC port within 0 - 1.1V, that is, the voltage output by the first set voltage source within the set threshold range is 0V to 1.1V. In this way, very fine control can be performed on the base voltage of the seventh switching transistor Q7.

[0072] From Figure 7 it can be seen that the parameters of the triode change greatly with the increase of temperature. Therefore, each time the current is adjusted before communication in the embodiment of the present invention, the DAC port first outputs a lower value. At this time, the current allowed to pass through the seventh switching transistor Q7 is also lower. Since the precision resistor Rs is connected in series in the main stream of the circuit, the peak current passing through the communication antenna 2 is equal to the peak current passing through the precision resistor Rs. The ADC port can calculate its current value by detecting the voltage on the precision resistor Rs. Through the feedback of detecting the current by the ADC, the PID algorithm inside the microcontroller unit can gradually increase the output of the DAC port to the expected value; since the circuit frequency of the embodiment of the present invention is 1 kHz, the normal PID algorithm only needs dozens of cycles to adjust the current to stability, corresponding to dozens of milliseconds. After the current adjustment is completed, normal communication can be carried out. For low-rate communication underground, the delay of dozens of milliseconds each time has no impact at all.

[0073] In other aspects of the embodiment of the present invention, multiple switching transistors are selected and connected in parallel for the seventh switching transistor Q7

[0074] It is formed by connection. If the system current is very large, one or more triodes can be connected in parallel based on the seventh switch tube Q7 to reduce the thermal load of a single triode. However, since the total resistance of the parallel-connected triodes becomes smaller at the output voltage of a certain DAC port, a higher-precision DAC port is required when adopting the parallel triode scheme.

[0075] In other aspects of the embodiments of the present invention, please refer to Figure 6 The high-temperature-resistant communication circuit further includes a first switch control circuit 4 electrically connected to the first input end, and a second switch control circuit 5 electrically connected to the second input end. The first switch control circuit 4 includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a fifth switch tube Q5; the first end of the third resistor R3 is electrically connected to the second set voltage source Vcc, the second end of the third resistor R3 is electrically connected to the control end of the fifth switch tube Q5, the first end of the fourth resistor R4 is electrically connected to the third set voltage source Vp, the second end of the fourth resistor R4 is respectively electrically connected to the first end of the fifth switch tube Q5 and the first input end, the first end of the fifth resistor R5 is electrically connected to the second end of the fifth switch tube Q5, and the second end of the fifth resistor R5 is used to receive the voltage signal input by the microprocessing unit 3. The second switch control circuit 5 includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a sixth switch tube Q6; the first end of the sixth resistor R6 is electrically connected to the second set voltage source Vcc, the second end of the sixth resistor R6 is electrically connected to the control end of the sixth switch tube Q6, the first end of the seventh resistor R7 is electrically connected to the third set voltage source Vp, the second end of the seventh resistor R7 is respectively electrically connected to the first end of the sixth switch tube Q6 and the second input end, the first end of the eighth resistor R8 is electrically connected to the second end of the sixth switch tube Q6, and the second end of the eighth resistor R8 is used to receive the voltage signal input by the microprocessing unit 3.

[0076] The fifth switch tube Q5 and the sixth switch tube Q6 are respectively selected from triodes or MOS tubes. In one embodiment, the fifth switch tube Q5 and the sixth switch tube Q6 are selected as triodes. The control end of the fifth switch tube Q5 is the base, the first end is the collector, and the second end is the emitter. The control end of the sixth switch tube Q6 is the base, the first end is the collector, and the second end is the emitter. The low-voltage power supply of the second set voltage source Vcc can be taken as 3.3V. The typical value of the third set voltage source Vp can be taken as 24V (typical value of the downhole

[0077] power supply). Since the driving method of the P tube is opposite to that of the N tube, the embodiments of the present invention add the fifth switch tube Q5 and the sixth switch tube Q6 to switch the first switch tube Q1 and the second switch tube Q2 through the I / O port of the microcontroller unit.

[0078] In other aspects of the embodiments of the present invention, please refer to Figure 6 A tenth resistor R10 is further connected in series to the gate of the third switching transistor Q3. The first end of the tenth resistor R10 is electrically connected to the gate of the third switching transistor Q3, and the second end of the tenth resistor R10 is electrically connected to the third output terminal S3. A ninth resistor R9 is further connected in series to the gate of the fourth switching transistor Q4. The first end of the ninth resistor R9 is electrically connected to the gate of the fourth switching transistor Q4, and the second end of the ninth resistor R9 is electrically connected to the fourth output terminal S4. By providing the ninth resistor R9 and the tenth resistor R10, damage to the circuit is prevented. When the MOS transistor is turned on, it is a charging process for its internal capacitors (such as the gate-source capacitor Cgs and the gate-drain capacitor Cgd), and the instantaneous current is very large. The series resistor can reduce the instantaneous current value and protect the drive chip.

[0079] In summary, the embodiment of the present invention is a full-bridge circuit composed of four switching transistors, namely the first switching transistor Q1 to the fourth switching transistor Q4, for driving the helical transmitting antenna in the middle. The switching signal is controlled by the micro-control unit. The seventh switching transistor Q7, the first resistor R1, (the second resistor R2), the precision resistor Rs, the ADC port, and the DAC port form a current control circuit to ensure the stability of the transmitting current at different temperatures, so as to obtain a stable and reliable communication link quality.

[0080] The communication circuit with high temperature resistance in the embodiment of the present invention has the following advantages:

[0081] 1. Low-frequency communication is performed using modulation methods such as frequency shift keying or binary phase shift keying modulation methods. Without a complex communication modulation and demodulation circuit, a certain downhole use bandwidth is ensured.

[0082] 2. Except for the high-temperature micro-control unit, other components are discrete devices, which have high reliability at high temperatures.

[0083] 3. Stable control of the transmitting current is achieved within a wide temperature range (typical downhole working environment, 0 - 200 °C). Due to the changes in the internal resistance of the device and the internal resistance of the load (antenna) brought about by the wide temperature range, ordinary power amplifier circuits cannot control the transmitting current well, which is likely to cause the transmitting current to be too low at some temperatures, resulting in a reduction in communication quality, and the transmitting current to be too high at some temperatures, causing the power supply to overload and restart, leading

[0084] to communication failure. The embodiment of the present invention controls the transmitting current through the current control circuit, which well ensures the stability and reliability of communication within a wide temperature range.

[0085] Method Embodiment

[0086] On the other hand, please refer to Figure 8 The embodiment of the present invention further provides a communication method for a communication circuit with high temperature resistance, which is applied to the above-mentioned communication circuit with high temperature resistance. The method includes:

[0087] Step 100: Control the microprocessing unit 3 to output a current within a set threshold range to the working end of the full-bridge drive circuit 1.

[0088] The microprocessing unit 3 includes a current control circuit for providing a current within a set threshold range for the working end. The current control circuit includes: a seventh switching transistor Q7, a first resistor R1, and a precision resistor. For the specific circuit of the current control circuit, reference can be made to the relevant description in the above circuit embodiment, which will not be elaborated here.

[0089] The current within the set threshold range in the embodiment of the present invention can be obtained through the following steps:

[0090] 1. Control the magnitudes and timings of the voltage signals input by the microprocessing unit 3 to the first input terminal, the second input terminal, the third input terminal, and the fourth input terminal of the full-bridge drive circuit 1 respectively, so as to generate a continuous alternating current on the communication antenna 2.

[0091] 2. Detect the current range at the first end of the precision resistor during the stage when a continuous alternating current is generated on the communication antenna 2, and use this current range as the current within the set threshold range.

[0092] The ADC port, DAC port, precision resistor Rs, seventh switching transistor Q7, first resistor R1, and second resistor R2 built in the microcontrol unit in the embodiment of the present invention together constitute a current control circuit. The DAC port outputs a first set voltage source. Among them, the precision resistor Rs is a precision resistor with an extremely low temperature coefficient, ensuring that its resistance value changes extremely little in a wide temperature range, especially at high temperatures. Its resistance value is generally selected as 0.1 ohm. Each time before the communication is officially started, control the full-bridge drive circuit 1 to run for several cycles first. The microcontrol unit can determine the output value of the DAC port by detecting the peak current of the circuit in these several cycles, and thus accurately control the current.

[0093] The circuit controls the current in the main circuit of the seventh switching transistor Q7 through the output of the DAC port.

[0094] Figure 7 V of a typical NPN transistor BE and I cThe relationship curve can be used to control Ic by precisely controlling the voltage of the DAC port. However, due to the small control range, in the embodiment of the present invention, a simple resistor network of the first resistor R1 and the second resistor R2 (Vcc = 3.3V, the ratio of the first resistor R1 to the second resistor R2 is about 2:1. For example, the first resistor R1 is 2K ohms and the second resistor R2 is 1K ohm) is adopted to control the control range of the DAC port within 0 - 1.1V, that is, the voltage output by the first set voltage source within the set threshold range is from 0V to 1.1V. In this way, very fine control can be performed on the base voltage of the seventh switching transistor Q7.

[0095] It can be seen from Figure 7 that the parameters of the triode change greatly with the increase of temperature. Therefore, in the embodiment of the present invention, each time the current is adjusted before communication, the DAC port first outputs a lower value. At this time, the current allowed to pass through the seventh switching transistor Q7 is also lower. Since the precision resistor Rs is connected in series in the main circuit, the peak current passing through the communication antenna 2 is equal to the peak current passing through the precision resistor Rs. The ADC port can calculate its current value by detecting the voltage on the precision resistor Rs. Through the feedback of the ADC detecting the current, the PID algorithm inside the micro-control unit can gradually increase the output of the DAC port to the expected value; since the circuit frequency of the embodiment of the present invention is 1KHz, the normal PID algorithm only needs dozens of cycles to adjust the current to be stable, corresponding to dozens of milliseconds. After the current adjustment is completed, normal communication can be carried out. For low-rate communication underground, the delay of dozens of milliseconds each time has no impact at all.

[0096] Step 200: Control the micro-processing unit 3 to input voltage signals of different magnitudes and timings to the first input end, the second input end, the third input end, and the fourth input end of the full-bridge drive circuit 1 respectively, so as to generate continuous alternating current on the communication antenna 2.

[0097] In one embodiment, the control micro-processing unit 3 inputs voltage signals of different magnitudes and timings to the first input end, the second input end, the third input end, and the fourth input end of the full-bridge drive circuit 1 respectively, so as to generate continuous alternating current on the communication antenna 2, including;

[0098] Repeat the following steps until the set end condition is obtained:

[0099] Step 210: Control the micro-processing unit 3 to input the turn-on voltage to the first input end and the fourth input end of the full-bridge drive circuit 1 respectively in the first cycle, and input the cut-off voltage to the second input end and the third input end of the full-bridge drive circuit

[0100] 1 respectively.

[0101] Step 220: Control the microprocessing unit 3 to input an enabling voltage to the fourth input terminal of the full-bridge drive circuit 1 in the second cycle, and input cut-off voltages to the first input terminal, the second input terminal, and the third input terminal of the full-bridge drive circuit 1 respectively.

[0102] Step 230: Control the microprocessing unit 3 to input cut-off voltages to the first input terminal and the fourth input terminal of the full-bridge drive circuit 1 in the third cycle respectively, and input enabling voltages to the second input terminal and the third input terminal of the full-bridge drive circuit 1 respectively.

[0103] Step 240: Control the microprocessing unit 3 to input an enabling voltage to the third input terminal of the full-bridge drive circuit 1 in the fourth cycle, and input cut-off voltages to the first input terminal, the second input terminal, and the fourth input terminal of the full-bridge drive circuit 1 respectively.

[0104] In one embodiment, the timing of the four I / O ports of the microcontroller unit, i.e., the first output terminal S1 to the fourth output terminal S4, for the full-bridge drive circuit 1 is as Figure 3 shown:

[0105] Starting from the 0 moment, the first output terminal S1 and the third output terminal S3 output low levels, and the fourth output terminal S4 and the second output terminal S2 output high levels. At the 1 / 4 cycle, i.e., the t1 moment, the output of the first output terminal S1 becomes high, the outputs of the fourth output terminal S4 and the second output terminal S2 remain high, and the output of the third output terminal S3 remains low. At the half cycle, i.e., the t2 moment, the output of the first output terminal S1 remains high, the outputs of the fourth output terminal S4 and the second output terminal S2 become low, and the output of the third output terminal S3 becomes high. At the 3 / 4 cycle, i.e., the t3 moment, the output of the first output terminal S1 remains high, the output of the fourth output terminal S4 remains low, the output of the second output terminal S2 becomes high, and the output of the third output terminal S3 remains high. At the end of the first complete cycle, i.e., the t4 moment, the output of the first output terminal S1 remains high, the output of the fourth output terminal S4 remains low, the output of the second output terminal S2 remains high, and the output of the third output terminal S3 remains high. Among them, the first cycle corresponds to Figure 3 the time period from 0 to t1 moment, the second cycle corresponds to Figure 3 the time period from t1 to t2 moment, the third cycle corresponds to Figure 3 the time period from t2 to t3 moment, and the fourth cycle corresponds to Figure 3 the time period from t3 to t4 moment.

[0106] Please refer to Figure 4 The switching states of the first switching transistor Q1 to the fourth switching transistor Q4 can be more intuitive

[0107] Understand its working principle. From 0 to t1, the first switching transistor Q1 and the fourth switching transistor Q4 are turned on, and the current passes through the helical antenna from left to right. From t1 to t2, the first switching transistor Q1 is turned off, and the fourth switch Q4 remains on. At this time, the energy in the helical antenna (which can be regarded as an inductor) is released through the loop of the fourth switch Q4 to the third diode D3. From t2 to t3, the second switching transistor Q2 and the third switching transistor Q3 are turned on, and the current passes through the helical antenna from right to left. From t3 to t4, the second switching transistor Q2 is turned off, and the third switching transistor Q3 remains on. At this time, the energy in the helical antenna (which can be regarded as an inductor) is released through the loop of the third switching transistor Q3 to the fourth diode D4. Through the above cycle, the current waveform passing through the helical antenna is as Figure 5 shown, and the positive current represents Figure 1 the current direction from left to right in

[0108] In addition, the microprocessing unit 3 in the embodiment of the present invention provides a voltage within a set threshold range to the working ends electrically connected to the third switching transistor Q3 and the fourth switching transistor Q4 through the DAC port, so as to set a current within a threshold range for the working ends. By controlling the emission current, the stability and reliability of communication within a wide temperature range are well ensured.

[0109] Chip embodiment

[0110] On the other hand, the embodiment of the present invention further provides a chip (not shown), including the above-mentioned high-temperature-resistant communication circuit, a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the communication method of the above-mentioned high-temperature-resistant communication circuit is realized.

[0112] Among them, the specific structure of the high-temperature resistant communication circuit refers to the above-mentioned embodiments. Since this chip adopts all the technical solutions of all the embodiments of the above-mentioned high-temperature resistant communication circuit, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be elaborated here one by one. The specific steps of the communication method of the high-temperature resistant communication circuit refer to the above-mentioned embodiments. Since this chip adopts all the technical solutions of all the embodiments of the communication method of the above-mentioned high-temperature resistant communication circuit, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be elaborated here one by one.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A communication circuit with high temperature resistance, characterized in that, Comprising: A full-bridge drive circuit, including a first input terminal, a second input terminal, a third input terminal, a fourth input terminal, an output terminal, and a working terminal; A communication antenna electrically connected to the output terminal of the full-bridge drive circuit; the communication antenna communicates using a modulation method of frequency shift keying or binary phase shift keying; A microprocessing unit electrically connected to the first input terminal, the second input terminal, the third input terminal, the fourth input terminal, and the working terminal respectively, for respectively controlling the magnitude and timing of the voltage signals input to the first input terminal, the second input terminal, the third input terminal, and the fourth input terminal, so as to generate continuous alternating current on the communication antenna, and for setting a threshold range of current for the working terminal.

2. The high-temperature resistant communication circuit according to claim 1, wherein The microprocessing unit includes a current control circuit for providing a current for setting the threshold range of the working terminal, and the current control circuit includes: a seventh switching tube, a first resistor, and a precision resistor; The control terminal of the seventh switching tube is electrically connected to the first end of the first resistor, the second end of the first resistor is electrically connected to a first set voltage source, the first set voltage source outputs a voltage within the set threshold range, the first end of the seventh switching tube is electrically connected to the working terminal, the second end of the seventh switching tube is electrically connected to the first end of the precision resistor, and the second end of the precision resistor is grounded.

3. The high-temperature resistant communication circuit according to claim 2, wherein The current control circuit further includes a second resistor, the first end of the second resistor is electrically connected to the control terminal of the seventh switching tube, and the second end of the second resistor is grounded.

4. The high-temperature resistant communication circuit according to claim 2, wherein The voltage output by the first set voltage source within the set threshold range is 0V to 1.1V.

5. The high-temperature resistant communication circuit according to claim 2, characterized in that, The seventh switching tube is formed by connecting multiple switching tubes in parallel.

6. The high-temperature resistant communication circuit according to claim 1, wherein The high-temperature resistant communication circuit further includes a first switch control circuit electrically connected to the first input terminal; the first switch control circuit includes a third resistor, a fourth resistor, a fifth resistor, and a fifth switching tube; the first end of the third resistor is electrically connected to a second set voltage source, the second end of the third resistor is electrically connected to the control terminal of the fifth switching tube, the first end of the fourth resistor is electrically connected to a third set voltage source, the second end of the fourth resistor is respectively electrically connected to the first end of the fifth switching tube and the first input terminal, the first end of the fifth resistor is electrically connected to the second end of the fifth switching tube, and the second end of the fifth resistor is used to receive the voltage signal input by the microprocessing unit.

7. The high-temperature resistant communication circuit according to claim 6, wherein The high-temperature resistant communication circuit further includes a second switch control circuit electrically connected to the second input terminal; the second switch control circuit includes a sixth resistor, a seventh resistor, an eighth resistor, and a sixth switching tube; the first end of the sixth resistor is electrically connected to a second set voltage source, the second end of the sixth resistor is electrically connected to the control terminal of the sixth switching tube, the first end of the seventh resistor is electrically connected to a third set voltage source, the second end of the seventh resistor is respectively electrically connected to the first end of the sixth switching tube and the second input terminal, the first end of the eighth resistor is electrically connected to the second end of the sixth switching tube, and the second end of the eighth resistor is used to receive the voltage signal input by the microprocessing unit.

8. The high-temperature resistant communication circuit according to claim 7, wherein, The fifth switching tube and the sixth switching tube are respectively selected from triodes or MOS tubes.

9. The high-temperature resistant communication circuit according to claim 1, characterized in that, The full-bridge drive circuit includes: a first switching tube, a second switching tube, a third switching tube, a fourth switching tube, a first diode, a second diode, a third diode, and a fourth diode; The first switching tube and the third switching tube are connected in series. The control end of the first switching tube serves as the first input terminal. The first switching tube and the first diode are connected in parallel. The third switching tube and the third diode are connected in parallel. The control end of the third switching tube serves as the third input terminal. The second switching tube and the fourth switching tube are connected in series. The control end of the second switching tube serves as the second input terminal. The second switching tube and the second diode are connected in parallel. The fourth switching tube and the fourth diode are connected in parallel. The control end of the fourth switching tube serves as the fourth input terminal. The first switching tube pair formed by the first switching tube and the third switching tube is connected in parallel with the second switching tube pair formed by the second switching tube and the fourth switching tube. The common end of the electrical connection between the third switching tube and the fourth switching tube serves as the working end.

10. The high-temperature resistant communication circuit according to claim 9, characterized in that, The first diode, the second diode, the third diode, and the fourth diode are respectively selected from freewheeling diodes.

11. The high-temperature resistant communication circuit according to claim 9, wherein, The first switching tube, the second switching tube, the third switching tube, and the fourth switching tube are respectively selected from triodes or MOS tubes.

12. A communication method for a high-temperature resistant communication circuit, characterized in that, Applied to the high-temperature-resistant communication circuit according to any one of claims 1 to 11, the method includes: Controlling the microprocessing unit to output a current within a set threshold range to the working end of the full-bridge drive circuit; Controlling the magnitudes and timings of the voltage signals input by the microprocessing unit to the first input terminal, the second input terminal, the third input terminal, and the fourth input terminal of the full-bridge drive circuit respectively, so as to generate a continuous alternating current on the communication antenna.

13. The communication method of the high-temperature resistant communication circuit according to claim 12, characterized in that, The microprocessing unit includes a current control circuit for providing a current within a set threshold range to the working end. The current control circuit includes: a seventh switching tube, a first resistor, and a precision resistor. The first end of the seventh switching tube is electrically connected to the working end. The second end of the seventh switching tube is electrically connected to the first end of the precision resistor. The current within the set threshold range is obtained through the following steps: Controlling the magnitudes and timings of the voltage signals input by the microprocessing unit to the first input terminal, the second input terminal, the third input terminal, and the fourth input terminal of the full-bridge drive circuit respectively, so as to generate a continuous alternating current on the communication antenna; Detecting the current range at the first end of the precision resistor during the stage when a continuous alternating current is generated on the communication antenna, and taking the current range as the current within the set threshold range.

14. The communication method of the high-temperature resistant communication circuit according to claim 13, characterized in that, Controlling the magnitudes and timings of the voltage signals input by the microprocessing unit to the first input terminal, the second input terminal, the third input terminal, and the fourth input terminal of the full-bridge drive circuit respectively, so as to generate a continuous alternating current on the communication antenna, includes; Repeatedly executing the following steps until a set end condition is obtained: Control the microprocessing unit to input an enabling voltage to the first input terminal and the fourth input terminal of the full-bridge drive circuit respectively in the first cycle, and input a cut-off voltage to the second input terminal and the third input terminal of the full-bridge drive circuit respectively; Control the microprocessing unit to input an enabling voltage to the fourth input terminal of the full-bridge drive circuit in the second cycle, and input a cut-off voltage to the first input terminal, the second input terminal and the third input terminal of the full-bridge drive circuit respectively; Control the microprocessing unit to input a cut-off voltage to the first input terminal and the fourth input terminal of the full-bridge drive circuit respectively in the third cycle, and input an enabling voltage to the second input terminal and the third input terminal of the full-bridge drive circuit respectively; Control the microprocessing unit to input an enabling voltage to the third input terminal of the full-bridge drive circuit in the fourth cycle, and input a cut-off voltage to the first input terminal, the second input terminal and the fourth input terminal of the full-bridge drive circuit respectively.

15. A chip, characterized in that, Comprising the high-temperature resistant communication circuit, memory, processor as claimed in any one of claims 1 to 11, and a computer program stored on the memory and executable on the processor, wherein when the processor executes the program, the communication method of the high-temperature resistant communication circuit as claimed in any one of claims 12 to 14 is implemented.

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