Communication circuit

Abstract

The invention discloses a communication circuit. The communication circuit comprises an input module, a power supply module and an output module. The power supply module is connected with the first end of the input module and is used for providing reference voltage for the input module; the second end of the input module is connected with an input voltage, the third end of the input module is connected with the control end of the output module, and the input module is used for outputting a control signal to the output module based on the input voltage and a reference voltage; a first end of the output module is connected with a first power supply, a second end of the output module is an output end of the communication circuit, and the output module is used for outputting an output voltage based on the control signal; wherein the reference voltage is a preset multiple of the threshold voltage of a transistor in the output module. According to the technical scheme, the communication accuracy is improved.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a communication circuit. Background Art

[0002] With the vigorous development of the automobile industry, the demand for various circuits in automobiles is becoming more and more vigorous. Among the circuits in automobiles, high-voltage communication circuits are a very important type of circuit.

[0003] In existing vehicles, most automotive electronic chips are designed and manufactured using the BCD (Bipolar-CMOS-DMOS) process. The output part of the high-voltage communication circuit may include a high-voltage transistor, that is, the high-voltage transistor outputs the output signal to achieve communication. When the process is poor, the channel of the high-voltage transistor will be larger, so its threshold voltage will be larger. When the process is better, the channel of the high-voltage transistor will become smaller.

[0004] When the channel of the high-voltage transistor becomes smaller, the duty cycle of the output signal output by the high-voltage transistor will become smaller, causing a large difference between the output signal and the input signal, affecting the accuracy of communication, that is, the signal transmission accuracy is low. Summary of the invention

[0005] The present invention provides a communication circuit to solve the problem of low accuracy of signal transmission in the communication circuit.

[0006] The present invention provides a communication circuit, which includes: an input module, a power module and an output module;

[0007] The power supply module is connected to the first end of the input module, and the power supply module is used to provide a reference voltage for the input module;

[0008] The second end of the input module is connected to the input voltage, the third end of the input module is connected to the control end of the output module, and the input module is used to output a control signal to the output module based on the input voltage and the reference voltage;

[0009] The first end of the output module is connected to a first power supply, the second end of the output module is the output end of the communication circuit, and the output module is used to output an output voltage based on the control signal; wherein the reference voltage is a preset multiple of the threshold voltage of the transistor in the output module.

[0010] Optionally, the input module is used to output the voltage of the control signal as the reference voltage when the input voltage is at a first level; and to output the voltage of the control signal as zero when the input voltage is at a second level;

[0011] The output module is used for outputting the output voltage as the first level when the voltage of the control signal is the reference voltage, and for outputting the output voltage as the second level when the voltage of the control signal is zero.

[0012] Optionally, the duty cycle of the input voltage and the preset multiple are reciprocals of each other.

[0013] Optionally, the power supply module includes a first current source and a voltage generating unit;

[0014] The first current source is connected between a first terminal of the voltage generating unit and a second power source, a second terminal of the voltage generating unit is grounded, and the voltage generating unit is used to generate the reference voltage.

[0015] Optionally, the power module further includes a feedback unit;

[0016] The first input end of the feedback unit is connected to the first end of the voltage generating unit, the second input end of the feedback unit is connected to the output end of the feedback unit, the output end of the feedback unit is connected to the first end of the input module, and the feedback unit is used to output the reference voltage.

[0017] Optionally, the voltage generating unit comprises n voltage generating transistors connected in series, and the control terminal of the voltage generating transistor is electrically connected to the first terminal of the voltage generating transistor;

[0018] The first end of the first voltage generating transistor is the first end of the voltage generating unit, the first end of the nth voltage generating transistor is connected to the second end of the n-1th voltage generating transistor, and the second end of the nth voltage generating transistor is grounded; wherein n is an integer greater than 1, and n is the preset multiple;

[0019] The threshold voltage of the voltage generating transistor is the same as the threshold voltage of the transistor in the output module.

[0020] Optionally, the feedback unit comprises an operational amplifier;

[0021] The first input terminal of the operational amplifier is the first input terminal of the feedback unit, the second input terminal of the operational amplifier is the second input terminal of the feedback unit, and the output terminal of the operational amplifier is the output terminal of the feedback unit.

[0022] Optionally, the input module includes a second current source, a first input transistor, a second input transistor, a third current source and a first capacitor;

[0023] A first end of the second current source is connected to the power module, and a second end of the second current source is connected to a first end of the first input transistor;

[0024] The control terminal of the first input transistor is connected to the input voltage, and the second terminal of the first input transistor is connected to the control terminal of the output module;

[0025] The control terminal of the second input transistor is connected to the input voltage, the first terminal of the second input transistor is connected to the control terminal of the output module, and the second terminal of the second input transistor is grounded through the third current source; wherein the second input transistor is of a different type from the first input transistor;

[0026] A first end of the first capacitor is connected to the control end of the output module, and a second end of the first capacitor is grounded.

[0027] Optionally, the output module includes an output transistor and a first resistor;

[0028] The control end of the output transistor is connected to the third end of the input module, the first end of the output transistor is connected to the first end of the first resistor, and the second end of the output transistor is grounded;

[0029] The second end of the first resistor is connected to the first power supply, and the first end of the first resistor is the output end of the output module.

[0030] Optionally, the output module further includes a first diode;

[0031] The first diode is connected between the first end of the first resistor and the first end of the output transistor.

[0032] The technical solution of the embodiment of the present invention provides a reference voltage for the input module through a power module, and the reference voltage is a preset multiple of the threshold voltage of the transistor in the output module. The preset multiple can be determined according to the duty cycle of the input voltage, and thus the reference voltage can be determined according to the duty cycle of the input voltage, so that when the duty cycle of the input voltage is large, the reference voltage can be small. Thus, the reference voltage will not differ greatly from the threshold voltage of the transistor in the output module, so that the conduction time of the output module will not be too long, so that the duty cycle of the output voltage output by the output module will not be too small, so that the duty cycle of the output voltage is consistent with the duty cycle of the input voltage, thereby improving the accuracy of communication.

[0033] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 is a structural schematic diagram of a communication circuit provided by an embodiment of the present invention;

[0036] Figure 2 is a structural schematic diagram of another communication circuit provided by an embodiment of the present invention;

[0037] Figure 3 is a structural schematic diagram of another communication circuit provided by an embodiment of the present invention;

[0038] Figure 4 It is a schematic diagram of a communication sequence provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0040] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0041] An embodiment of the present invention provides a communication circuit. Figure 1 is a schematic diagram of a communication circuit provided by an embodiment of the present invention, with reference to Figure 1 , the communication circuit includes: an input module 110, a power module 120 and an output module 130;

[0042] The power module 120 is connected to the first end of the input module 110, and the power module 120 is used to provide a reference voltage for the input module 110;

[0043] The second end of the input module 110 is connected to the input voltage VIN, and the third end of the input module 110 is connected to the control end FB of the output module 130. The input module 110 is used to output a control signal to the output module 130 based on the input voltage VIN and the reference voltage.

[0044] The first end of the output module 130 is connected to the first power supply VBAT, the second end of the output module 130 is the output end OUT of the communication circuit, and the output module 130 is used to output an output voltage based on a control signal; wherein the reference voltage is a preset multiple of the threshold voltage of the transistor in the output module 130.

[0045] For example, the input voltage VIN is a pulse signal, including a high level voltage and a low level voltage. The input module 110 can convert the input voltage VIN and output a control signal. The power module 120 can include a power conversion circuit or a power conversion chip, etc. The power module 120 can output a reference voltage to power the input module 110, so that the input module 110 can output a control signal based on the input voltage VIN and the reference voltage.

[0046] Specifically, the input module 110 can convert the input voltage VIN, output a control signal according to the level of the input voltage VIN, and the level of the control signal can be determined based on the reference voltage, for example, the control signal outputting a high level is the reference voltage. The output module 130 can be turned on or off according to the control signal, thereby outputting output voltages of different levels. For example, when the input module 110 outputs a control signal based on a low-level input voltage VIN, the output module 130 outputs a low-level output voltage, and when the input module 110 outputs a control signal based on a high-level input voltage VIN, the output module 130 outputs a high-level output voltage, so that the output voltage is consistent with the input voltage VIN.

[0047] The output module 130 includes a transistor, and the control end of the transistor in the output module 130 is the control end of the output module 130. According to the characteristics of the transistor, when the voltage of the control end of the transistor in the output module 130 is equal to the threshold voltage of the transistor, a Miller platform will be generated during the change of the potential of the control end of the transistor in the output module 130, so that the voltage of the control end of the transistor in the output module 130 stops changing, and the conduction state of the transistor in the output module 130 changes. For example, in the process of increasing the potential of the control end of the transistor in the output module 130, when the voltage of the control end of the transistor in the output module 130 increases to the Miller platform, the transistor in the output module 130 starts to turn on; in the process of decreasing the potential of the control end of the transistor in the output module 130, when the voltage of the control end of the transistor in the output module 130 decreases to the Miller platform, the transistor in the output module 130 starts to turn off. Therefore, in the process of the voltage change of the control signal, when the voltage of the control end of the transistor in the output module 130 reaches the threshold voltage of the transistor (when encountering the Miller platform), the state of the output module 130 will change.

[0048] That is, the difference between the reference voltage and the threshold voltage will affect the conduction time of the output module 130. When the reference voltage differs greatly from the threshold voltage, the time for the control terminal of the output module 130 to increase from the threshold voltage to the reference voltage is longer, and the time for the control terminal of the output module 130 to decrease from the reference voltage to the reference voltage is also longer, and the conduction time of the output module 130 is longer; when the difference between the reference voltage and the threshold voltage is small, the conduction time of the output module 130 is shorter. The technical solution of this embodiment provides a reference voltage for the input module 110 through the power module 120, and the reference voltage can be adjusted according to demand. By setting the reference voltage to a preset multiple of the threshold voltage of the transistor in the output module 130, the preset multiple can be determined according to the duty cycle of the input voltage VIN, thereby determining the reference voltage according to the duty cycle of the input voltage VIN, so that when the duty cycle of the input voltage VIN is relatively large, the reference voltage can be relatively small, so that the reference voltage and the threshold voltage of the transistor in the output module 130 will not differ greatly, so that the conduction time of the transistor in the output module 130 will not be too long, that is, the conduction time of the output module 130 will not be too long, so that the duty cycle of the output voltage output by the output module 130 will not be too small, so that the duty cycle of the output voltage is consistent with the duty cycle of the input voltage VIN, thereby improving the accuracy of communication.

[0049] The technical solution of this embodiment provides a reference voltage for the input module through the power module. The reference voltage is a preset multiple of the threshold voltage of the transistor in the output module. The preset multiple can be determined according to the duty cycle of the input voltage, and the reference voltage can be determined according to the duty cycle of the input voltage, so that when the duty cycle of the input voltage is large, the reference voltage can be small. Therefore, the reference voltage will not differ greatly from the threshold voltage of the transistor in the output module, so that the conduction time of the output module will not be too long, so that the duty cycle of the output voltage output by the output module will not be too small, so that the duty cycle of the output voltage is consistent with the duty cycle of the input voltage, thereby improving the accuracy of communication.

[0050] On the basis of the above technical solution, optionally, the input module 110 is used to output the voltage of the control signal as the reference voltage when the input voltage is at the first level; and to output the voltage of the control signal as zero when the input voltage is at the second level;

[0051] The output module 130 is used to output an output voltage of a first level when the voltage of the control signal is a reference voltage, and to output an output voltage of a second level when the voltage of the control signal is zero.

[0052] The transistors in the output module 130 may be high-voltage transistors, so that the output voltage output by the output module 130 can be relatively large, and the communication circuit is a high-voltage communication circuit, thus realizing high-voltage communication.

[0053] The first level is a high level and the second level is a low level; or the first level is a low level and the second level is a high level. The following description is made by taking the first level as a high level and the second level as a low level as an example, but this is not intended to limit the present application.

[0054] Exemplarily, the input module 110 can convert the input voltage VIN, for example, the level of the input voltage VIN can be inverted. When the input voltage VIN is at a high level, the input module 110 outputs a low-level control signal, and when the input voltage VIN is at a low level, the input module 110 outputs a high-level control signal. Among them, the high-level control signal can be different from the voltage value of the high-level input voltage VIN, and the voltage value of the high-level control signal is determined based on the reference voltage, that is, the voltage corresponding to the high-level control signal is the reference voltage. When the input module 110 outputs a high-level control signal, the output module 130 responds to the high-level control signal to turn on and output a low-level output voltage. When the input module 110 outputs a low-level control signal, the output module 130 responds to the low-level control signal to turn off and output a high-level output voltage. The high-level output voltage is the same as the voltage value of the high-level input voltage, and the low-level output voltage is the same as the voltage value of the low-level input voltage, so that the output module 130 outputs the input voltage to achieve accurate communication.

[0055] Specifically, due to the presence of transistors in the output module 130, the signal at the control end of the output module 130 will encounter the Miller platform during the change process, and a stage of voltage suspension change will occur. Therefore, in the process of the control signal output by the input module 110 changing from a low level to a high level, a stage of voltage suspension change will occur, and in the process of the control signal output by the input module 110 changing from a high level to a low level, a stage of voltage suspension change will occur. According to the characteristics of the transistor, in the Miller platform, the voltage at the control end of the transistor in the output module 130 is equal to the threshold voltage of the transistor in the output module 130, that is, the voltage corresponding to the control signal is the threshold voltage of the transistor in the output module 130. Therefore, when the control signal output by the input module 110 changes from a low level to the Miller platform, the output module 130 starts to conduct and outputs a low-level output voltage. When the control signal output by the input module 110 changes from the Miller platform to a high-level control signal, the output module 130 outputs a low-level output voltage. When the control signal output by the input module 110 is reduced from a high-level control signal to the Miller platform, the output module 130 outputs a low-level output voltage. The output module 130 will be turned off and output a high-level output voltage only when the control signal output by the input module 110 is reduced from the Miller platform to the low-level output voltage. The difference between the reference voltage and the threshold voltage will affect the conduction time of the output module 130. When the reference voltage differs greatly from the threshold voltage, the time for the control end of the output module 130 to rise from the threshold voltage to the reference voltage is longer, and the time for the control end of the output module 130 to decrease from the reference voltage to the reference voltage is also longer, so that the conduction time of the output module 130 is longer; when the difference between the reference voltage and the threshold voltage is small, the conduction time of the output module 130 is shorter. The technical solution of this embodiment, by setting the reference voltage to a preset multiple of the threshold voltage of the transistor in the output module 130, can determine the preset multiple according to the duty cycle of the input voltage VIN, so that the reference voltage will not be too large, that is, the voltage of the high-level control signal will not be too large, thereby avoiding the problem that the output module 130 outputs a low-level output voltage for a long time, so that the duty cycle of the output voltage is small, and the signal cannot be accurately transmitted.

[0056] Based on the above technical solutions, optionally, the duty cycle of the input voltage and the preset multiple are reciprocals of each other.

[0057] Exemplarily, when the duty cycle of the input voltage VIN is 50%, the preset multiple is 2, so that in one cycle (the cycle of the input voltage VIN, that is, the cycle of the control signal), the duration of the output module 130 outputting a low-level output voltage is the same as the duration of the output high-level output voltage, thereby outputting an output voltage with a duty cycle of 50%, so that the output voltage is consistent with the duty cycle of the input voltage VIN, thereby improving the accuracy of communication.

[0058] On the basis of the above technical solutions, Figure 2 is a schematic diagram of a structure of another communication circuit provided by an embodiment of the present invention. Figure 2 , the power module 120 includes a first current source 121 and a voltage generating unit 122;

[0059] The first current source 121 is connected between a first terminal of the voltage generating unit 122 and the second power source VDD. A second terminal of the voltage generating unit 122 is grounded. The voltage generating unit 122 is used to generate a reference voltage.

[0060] Specifically, the voltage generating unit 122 can convert the voltage of the second power supply VDD to generate a reference voltage. The voltage generating unit 122 can include a voltage conversion circuit or a voltage conversion chip, and can also include other voltage limiting devices, etc. By setting the first current source 121, the first current source 121 can generate a stable current, so that the current of the voltage generating unit 122 is stable, thereby outputting a stable reference voltage, thereby improving the stability and reliability of the reference voltage, which is conducive to the input module 110 outputting a stable control signal, better controlling the output of the output module 130, and improving the reliability and stability of the communication circuit.

[0061] Optionally, refer to Figure 2 , the power module 120 further includes a feedback unit 123;

[0062] The first input terminal of the feedback unit 123 is connected to the first terminal of the voltage generating unit 122, the second input terminal of the feedback unit 123 is connected to the output terminal of the feedback unit 123, the output terminal of the feedback unit 123 is connected to the first terminal of the input module 110, and the feedback unit 123 is used to output a reference voltage.

[0063] Specifically, the feedback unit 123 can feed back the voltage at its output end to the second input end of the feedback unit 123, thereby adjusting the voltage output by the feedback unit 123, so that the voltage output by the feedback unit 123 can follow the voltage at the first input end of the feedback unit 123, and then make the reference voltage output by the feedback unit 123 consistent with the voltage output by the voltage generating unit 122, thereby ensuring that the accurate reference voltage is transmitted to the input module 110, further improving the reliability and stability of the communication circuit.

[0064] On the basis of the above technical solutions, Figure 3 is a schematic diagram of a structure of another communication circuit provided by an embodiment of the present invention. Figure 3 , the voltage generating unit 122 includes n voltage generating transistors ML connected in series, and the control terminal of the voltage generating transistor ML is electrically connected to the first terminal of the voltage generating transistor ML;

[0065] The first end of the first voltage generating transistor ML is the first end of the voltage generating unit 122, the first end of the nth voltage generating transistor ML is connected to the second end of the n-1th voltage generating transistor ML, and the second end of the nth voltage generating transistor ML is grounded; wherein n is an integer greater than 1, and n is a preset multiple;

[0066] The voltage generating transistor ML is of the same type as the transistors in the output module 130 , for example, both are high-voltage N-type transistors or high-voltage P-type transistors. The threshold voltage of the voltage generating transistor ML is the same as the threshold voltage of the transistors in the output module 130 .

[0067] Specifically, the control terminal of the voltage generating transistor ML is electrically connected to the first terminal of the voltage generating transistor ML, so that the potential of the first terminal of the voltage generating transistor ML is the threshold voltage of the voltage generating transistor ML, that is, the threshold voltage of the transistor in the output module 130. By connecting n voltage generating transistors ML in series, the reference voltage generated by the voltage generating unit 122 is n times the threshold voltage, that is, a preset multiple of the threshold voltage.

[0068] in, Figure 3 , the first voltage generating transistor ML is close to the first current source 121 , and the nth voltage generating transistor ML is far from the first current source 121 .

[0069] Optionally, refer to Figure 3 , the feedback unit 123 includes an operational amplifier U1;

[0070] The first input terminal of the operational amplifier U1 is the first input terminal of the feedback unit 123 , the second input terminal of the operational amplifier U1 is the second input terminal of the feedback unit 123 , and the output terminal of the operational amplifier U1 is the output terminal of the feedback unit 123 .

[0071] The first input terminal of the operational amplifier U1 may be a non-inverting input terminal, and the second input terminal of the operational amplifier U1 may be an inverting input terminal.

[0072] Specifically, by connecting the output end of the operational amplifier U1 to the second input end of the operational amplifier U1, the amplification factor of the operational amplifier U1 is made 1, so that the voltage output by the operational amplifier U1 follows the voltage of the first input end of the operational amplifier U1, and then the reference voltage output by the operational amplifier U1 is consistent with the voltage output by the voltage generating unit 122, thereby ensuring that the accurate reference voltage is transmitted to the input module 110, further improving the reliability and stability of the communication circuit.

[0073] Optionally, refer to Figure 3 , the input module 110 includes a second current source 111, a first input transistor M1, a second input transistor M2, a third current source 112 and a first capacitor C1;

[0074] A first end of the second current source 111 is connected to the power module 120 , and a second end of the second current source 111 is connected to a first end of the first input transistor M1 ;

[0075] The control terminal of the first input transistor M1 is connected to the input voltage VIN, and the second terminal of the first input transistor M1 is connected to the control terminal of the output module 130;

[0076] The control terminal of the second input transistor M2 is connected to the input voltage VIN, the first terminal of the second input transistor M2 is connected to the control terminal of the output module 130, and the second terminal of the second input transistor M2 is grounded through the third current source 112; wherein the second input transistor M2 is of a different type from the first input transistor M1;

[0077] A first end of the first capacitor C1 is connected to the control end of the output module 130 , and a second end of the first capacitor is grounded.

[0078] Specifically, the second input transistor M2 is of a different type from the first input transistor M1, so that the second input transistor M2 and the first input transistor M1 can be turned on in response to different levels of input voltage VIN. For example, the second input transistor M2 is an N-type transistor, and the first input transistor M1 is a P-type transistor. For example, the first input transistor M1 and the second input transistor M2 are both low-voltage transistors.

[0079] When the input voltage VIN is at a high level, the second input transistor M2 is turned on, the first input transistor M1 is turned off, and the potential output to the control terminal of the output module 130 is zero, that is, a low-level control signal is output, and the output module 130 is turned off in response to the low-level control signal, and outputs a high-level output voltage. When the input voltage VIN is at a low level, the first input transistor M1 is turned on, the second input transistor M2 is turned off, and the first input transistor M1 outputs a high-level control signal, that is, outputs a reference voltage, so that the output module 130 is turned on in response to the high-level control signal, and outputs a low-level output voltage. In this way, the input voltage VIN is output.

[0080] By setting the first capacitor C1, when the first input transistor M1 is turned on, the reference voltage charges the first capacitor C1 through the first input transistor M1, so that the voltage at the first end of the first capacitor C1 gradually increases, that is, the voltage at the control end of the output module 130 gradually increases. When the voltage at the control end of the output module 130 reaches the threshold voltage of the output module 130, the parasitic capacitance between the gate and source of the transistor in the output module 130 begins to be charged, so that the voltage at the first end of the first capacitor C1 remains unchanged, and the voltage at the control end of the output module 130 remains unchanged, that is, reaches the Miller platform. After the parasitic capacitance is fully charged, the first capacitor C1 continues to be charged until the voltage at the first end of the first capacitor C1 reaches the reference voltage. When the second input transistor M2 is turned on, the first capacitor C1 is discharged through the second input transistor M2, so that the voltage at the first end of the first capacitor C1 gradually decreases. When the voltage at the first end of the first capacitor C1 reaches the threshold voltage of the transistor in the output module 130, the transistor in the output module 130 is turned off, and the parasitic capacitance of the transistor in the output module 130 is discharged, so that the voltage at the first end of the first capacitor C1 remains unchanged and reaches the Miller platform. After the parasitic capacitance is discharged, the voltage at the first end of the first capacitor C1 continues to decrease until it is reduced to zero.

[0081] When the voltage at the first end of the first capacitor C1 increases to the threshold voltage of the transistor in the output module 130 , the output module 130 starts to conduct and outputs a low-level output voltage until the voltage at the first end of the first capacitor C1 decreases to the threshold voltage of the transistor in the output module 130 .

[0082] For example, when the duty cycle of the input voltage VIN is 50%, the reference voltage is twice the threshold voltage of the transistor in the output module 130, so that in one cycle (the cycle of the input voltage, that is, the cycle of the control signal), the on-time and off-time of the output module 130 are the same, so that the duty cycle of the output voltage of the output module 130 is 50%, so that the output voltage is consistent with the input voltage VIN.

[0083] By providing the second current source 111 and the third current source 112 , the currents of the second input transistor M2 and the first input transistor M1 are stabilized, so that the control signal output by the input module 110 is stabilized, which is beneficial to improving the reliability and stability of the communication circuit.

[0084] Optionally, refer to Figure 3 , the output module 130 includes an output transistor MO and a first resistor R1;

[0085] The control end of the output transistor MO is connected to the third end of the input module 110, the first end of the output transistor MO is connected to the first end of the first resistor R1, and the second end of the output transistor MO is grounded;

[0086] The second end of the first resistor R1 is connected to the first power source VBAT, and the first end of the first resistor R1 is the output end OUT of the output module 130 .

[0087] Specifically, the transistor in the output module 130 is the output transistor MO. The output transistor MO can be an N-type transistor. After the first input transistor M1 is turned on, the voltage of the control signal rises from zero to the threshold voltage of the output transistor MO, and the output transistor MO starts to turn on and outputs a low-level output voltage. The voltage of the control signal continues to rise and rises to the reference voltage. After the second input transistor M2 is turned on, the voltage of the control signal is reduced from the reference voltage to the threshold voltage of the output transistor MO, and the output transistor MO is turned off, so that the voltage at the first end of the output transistor MO is a high-level voltage, that is, a high-level output voltage is output. In this way, the output transistor MO outputs an output voltage including a high level and a low level, thereby realizing the transmission of the communication signal.

[0088] By setting the first resistor R1, current limiting can be performed to avoid a large current of the first power supply VBAT, so that the current of the output voltage is large. The first power supply VBAT can be provided by a battery, or by a mains or other power supply device, which is not limited in this embodiment.

[0089] Optionally, refer to Figure 3 The output module 130 further includes a first diode D1; the first diode D1 is connected between the first end of the first resistor R1 and the first end of the output transistor MO. In this way, the current in the output module 130 flows from the first power supply VBAT to the output transistor MO, which can ensure that the output module 130 normally outputs high-level and low-level output voltages.

[0090] For example, Figure 4 is a schematic diagram of a communication sequence provided by an embodiment of the present invention. Figure 4, in the t1 stage, the input voltage VIN is at a low level, so that the first input transistor M1 in the input module 110 is turned on, the second input transistor M2 is turned off, and the reference voltage VREF_N charges the first capacitor C1 through the first input transistor M1, so that the voltage at the first end of the first capacitor C1 gradually increases, and the voltage VFB of the control signal output by the first input transistor M1 gradually increases. In the t2 stage, the voltage VFB of the control signal reaches the threshold voltage of the output transistor MO, the output transistor MO starts to turn on, and the output voltage VOUT output by the output transistor MO gradually decreases until it decreases to a low level, so as to output the output voltage VOUT at a low level; the reference voltage VREF_N continues to charge the first capacitor C1 through the first input transistor M1, and the voltage VFB of the control signal output by the first input transistor M1 continues to increase until it increases to the reference voltage VREF_N; then the input voltage VIN becomes a high level, that is, the voltage of the second power supply VDD, the second input transistor M2 is turned on, the first input transistor M1 is turned off, the first capacitor C1 is discharged through the second input transistor M2, and the voltage VFB of the control signal output by the second input transistor M2 begins to decrease. In the t3 stage, the voltage VFB of the control signal output by the second input transistor M2 reaches the threshold voltage of the output transistor MO, the output transistor MO starts to shut down, and the output voltage VOUT of the output module 130 becomes high level, that is, the voltage of the first power supply VBAT, the first capacitor C1 continues to discharge, and the output module 130 continues to output the high level output voltage VOUT. In this way, the output of one cycle is completed. In addition, the reference voltage is a preset multiple of the threshold voltage of the transistor in the output module 130, and the preset multiple can be determined according to the duty cycle of the input voltage VIN, so that the reference voltage will not be too large, that is, the voltage of the high level control signal will not be too large, thereby avoiding the output module 130 outputting a low level output voltage for a long time, so that the duty cycle of the output voltage is relatively small, and the problem of being unable to accurately transmit the signal.

[0091] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A communication circuit, characterized in that: include: Input module, power module and output module; The power supply module is connected to the first end of the input module, and the power supply module is used to provide a reference voltage for the input module; The second end of the input module is connected to the input voltage, the third end of the input module is connected to the control end of the output module, and the input module is used to output a control signal to the output module based on the input voltage and the reference voltage; The first end of the output module is connected to a first power supply, the second end of the output module is the output end of the communication circuit, and the output module is used to output an output voltage based on the control signal; wherein the reference voltage is a preset multiple of the threshold voltage of the transistor in the output module.

2. The communication circuit according to claim 1, characterized in that: The input module is used for outputting the voltage of the control signal as the reference voltage when the input voltage is at a first level; and outputting the voltage of the control signal as zero when the input voltage is at a second level; The output module is used for outputting the output voltage as the first level when the voltage of the control signal is the reference voltage, and for outputting the output voltage as the second level when the voltage of the control signal is zero.

3. The communication circuit according to claim 1, characterized in that: The duty cycle of the input voltage and the preset multiple are reciprocals of each other.

4. The communication circuit according to claim 1, characterized in that: The power supply module includes a first current source and a voltage generating unit; The first current source is connected between a first terminal of the voltage generating unit and a second power source, a second terminal of the voltage generating unit is grounded, and the voltage generating unit is used to generate the reference voltage.

5. The communication circuit according to claim 4, characterized in that: The power module also includes a feedback unit; The first input end of the feedback unit is connected to the first end of the voltage generating unit, the second input end of the feedback unit is connected to the output end of the feedback unit, the output end of the feedback unit is connected to the first end of the input module, and the feedback unit is used to output the reference voltage.

6. The communication circuit according to claim 4, characterized in that: The voltage generating unit comprises n voltage generating transistors connected in series, wherein the control terminal of the voltage generating transistor is electrically connected to the first terminal of the voltage generating transistor; The first end of the first voltage generating transistor is the first end of the voltage generating unit, the first end of the nth voltage generating transistor is connected to the second end of the n-1th voltage generating transistor, and the second end of the nth voltage generating transistor is grounded; wherein n is an integer greater than 1, and n is the preset multiple; The threshold voltage of the voltage generating transistor is the same as the threshold voltage of the transistor in the output module.

7. The communication circuit according to claim 5, characterized in that: The feedback unit includes an operational amplifier; The first input terminal of the operational amplifier is the first input terminal of the feedback unit, the second input terminal of the operational amplifier is the second input terminal of the feedback unit, and the output terminal of the operational amplifier is the output terminal of the feedback unit.

8. The communication circuit according to claim 1, characterized in that: The input module includes a second current source, a first input transistor, a second input transistor, a third current source and a first capacitor; A first end of the second current source is connected to the power module, and a second end of the second current source is connected to a first end of the first input transistor; The control terminal of the first input transistor is connected to the input voltage, and the second terminal of the first input transistor is connected to the control terminal of the output module; The control terminal of the second input transistor is connected to the input voltage, the first terminal of the second input transistor is connected to the control terminal of the output module, and the second terminal of the second input transistor is grounded through the third current source; wherein the second input transistor is of a different type from the first input transistor; A first end of the first capacitor is connected to the control end of the output module, and a second end of the first capacitor is grounded.

9. The communication circuit according to claim 1, characterized in that: The output module includes an output transistor and a first resistor; The control end of the output transistor is connected to the third end of the input module, the first end of the output transistor is connected to the first end of the first resistor, and the second end of the output transistor is grounded; The second end of the first resistor is connected to the first power supply, and the first end of the first resistor is the output end of the output module.

10. The communication circuit according to claim 9, characterized in that: The output module also includes a first diode; The first diode is connected between the first end of the first resistor and the first end of the output transistor.

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