Reconfigurable bidirectional transmit-receive circuit

Abstract

The invention relates to the technical field of serial / deserializer data transmission, in particular to a reconfigurable bidirectional transceiving circuit which comprises a main transmitter and a copy transmitter, the main transmitter comprises a first power supply, a second power supply, a first phase inverter, a second phase inverter, a first variable resistor, a second variable resistor, a first current mirror and a second current mirror, the first variable resistor is connected with the first phase inverter in parallel, the output end of the first power supply is connected with the input end of the first phase inverter, the output end of the first phase inverter is connected with the output end of the first current mirror, and the second variable resistor is connected with the second phase inverter in parallel. The output end of the second power supply is connected with the input end of the second phase inverter, and the output end of the second phase inverter is connected with the output end of the second current mirror. On the basis of realizing low power consumption, the output amplitude can be flexibly adjusted to meet the requirements of different application scenes, and the application performance of the bidirectional transceiver circuit is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of serial / deserializer data transmission; in particular, the present invention relates to a reconfigurable bidirectional transceiver circuit. Background Art

[0002] In the field of automotive communications, asymmetric full-duplex serial / deserializer (SerDes) technology is widely used in scenarios such as vehicle-mounted cameras and vehicle-mounted multimedia audio and video transmission.

[0003] The Chinese invention No. 118100969A "Vehicle-mounted high-speed transmission circuit, including a serializer / deserializer and a method of using the same" provides a vehicle-mounted full-duplex transmission circuit that supports both single-ended and common-mode reverse link transmission while achieving low power consumption, meeting the development needs of data transmission technology in the field of automotive communications.

[0004] However, this circuit also has certain defects, such as poor flexibility and the inability to dynamically adjust the amplitude of the output signal according to the actual usage scenario. Summary of the invention

[0005] In view of this, the present invention provides a reconfigurable bidirectional transceiver circuit, which can improve the flexibility of the transceiver circuit.

[0006] In order to achieve the aforementioned objectives, the present invention provides a reconfigurable bidirectional transceiver circuit, comprising a main transmitter and a replica transmitter, wherein the main transmitter is used to send a first forward signal, the replica transmitter is connected in parallel to the main transmitter, and the replica transmitter is used to send a second forward signal, and the main transmitter and the replica transmitter have the same structure; the main transmitter comprises a first power supply, a second power supply, a first inverter, a second inverter, a first variable resistor, a second variable resistor, a first current mirror and a second current mirror, the first variable resistor is connected in parallel with the first inverter, the output end of the first power supply is connected to the input end of the first inverter, the output end of the first inverter is connected to the output end of the first current mirror, the second variable resistor is connected in parallel with the second inverter, the output end of the second power supply is connected to the input end of the second inverter, and the output end of the second inverter is connected to the output end of the second current mirror.

[0007] In the above scheme, compared with the traditional voltage-mode driver, the output is an inverter-based TIA structure, and two upper and lower dual current mirrors are added. The load of the TIA structure can increase the bandwidth of the driver output, allowing the driver to transmit data at a faster rate. By introducing upper and lower dual current mirrors, the voltage-mode driver swing can be adjusted to adjust the driver output swing to be greater than VDD / 2, equal to VDD / 2, and less than VDD / 2. On the basis of retaining the advantage of low power consumption of the original structure, the output amplitude is flexible and configurable, which can cover more application scenarios.

[0008] A further improved solution further includes a signal separation circuit, wherein the output end of the main transmitter and the output end of the replica transmitter are respectively connected to the input end of the signal separation circuit, and the signal separation circuit is used to separate the reverse signal through the first forward signal.

[0009] In a further optimized solution, the signal separation circuit includes a first RC unit, a second RC unit, a third RC unit, a fourth RC unit and a third switch. The first RC unit, the second RC unit, the third RC unit and the fourth RC unit are all composed of a resistor and a capacitor in series. The capacitor end of the first RC unit is connected to the first inverter output end of the replica transmitter, the resistor end of the first RC unit is connected to the resistor end of the third RC unit, and the capacitor end of the third RC unit is connected to the first inverter output end of the main transmitter; the capacitor end of the second RC unit is connected to the second inverter output end of the replica transmitter, the resistor end of the second RC unit is connected to the resistor end of the fourth RC unit, and the capacitor end of the fourth RC unit is connected to the second inverter output end of the main transmitter. The third switch is connected between the fourth switch 1 and the fourth switch 2.

[0010] In the above scheme, the use of multiple RC units can not only separate the reverse signal, but also the capacitor can isolate the influence of the replica transmitter on the DC bias of the main transmitter, thereby not affecting the output state of the main transmitter, thereby ensuring the reliability and stability of signal transmission.

[0011] A further improved solution further includes a pre-driver, which is located upstream of the main transmitter and the replica transmitter, and is used to drive the main transmitter and the replica transmitter to respectively transmit a first forward signal and a second forward signal.

[0012] In a further optimized solution, the pre-driver includes a first pre-driver and a second pre-driver, the output end of the first pre-driver is connected to the first power input end of the main transmitter and the second power input end of the replica transmitter, and the output end of the second pre-driver is connected to the second power input end of the main transmitter and the first power input end of the replica transmitter.

[0013] In a further optimized solution, the output end of the first pre-driver is connected to the first power input end of the main transmitter and the first power input end of the replica transmitter through the first switch 1, and the output end of the second pre-driver is connected to the second power input end of the main transmitter and the second power input end of the replica transmitter through the first switch 2; the second switch 2 is connected between the first power input end of the main transmitter and the second power input end of the replica transmitter, and the second switch 1 is connected between the second power input end of the main transmitter and the first power input end of the replica transmitter; the resistance end of the first RC unit is connected to the resistance end of the third RC unit through the fourth switch 1, and the resistance end of the second RC unit is connected to the resistance end of the fourth RC unit through the fourth switch 2;

[0014] The reconfigurable bidirectional transceiver circuit further includes a switch signal configuration module for outputting a first switch control signal, a second switch control signal, a third switch control signal, and a fourth switch control signal.

[0015] In the above scheme, the first switch control signal, the second switch control signal, the third switch control signal, and the fourth switch control signal are used to control the opening or closing of the first switch, the second switch, the third switch, and the fourth switch, respectively. The first switch controls the on-off of the pre-driver output, the second switch controls the on-off of the replica transmitter input, and the third switch and the fourth switch control the selection of the signal separation mode in the signal separation circuit, the single-end application mode or the double-end application mode.

[0016] Compared with the prior art, the present invention can be flexibly configured to meet different needs. For example, the present invention has the following advantages:

[0017] 1.Support single-ended and double-ended cable applications, where double-ended cable applications support reverse transmission of differential and common mode signals.

[0018] 2.Support amplitude adjustment, multiple amplitude output can be flexibly configured.

[0019] 3. Support time division multiplexing, can be configured as single transmitter mode or single receiver mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The disclosure of the present invention will become more apparent with reference to the accompanying drawings. It should be understood that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. In the drawings:

[0021] Figure 1 The figure is a schematic diagram of the structure of an embodiment of a reconfigurable bidirectional transceiver circuit of the present invention.

[0022] Figure 2 A schematic diagram of the structure of a commonly used transmitter.

[0023] Figure 3a , Figure 3b , Figure 3c They are the circuit configuration diagrams when the output swing is VDD / 2+IR, VDD / 2, and VDD / 2-IR respectively. DETAILED DESCRIPTION

[0024] With reference to the accompanying drawings and specific embodiments, the structure, composition, characteristics and advantages of the vehicle-mounted high-speed transmitting circuit of the present invention, including the serializer / deserializer thereof and the use method thereof, will be explained below in an exemplary manner. However, all descriptions should not be used to form any limitations on the present invention.

[0025] In addition, for any single technical feature described or implied in the embodiments mentioned in this document, or any single technical feature displayed or implied in the accompanying drawings, the present invention still allows for continued arbitrary combination or deletion between these technical features (or their equivalents) without any technical obstacles, and thus it should be considered that these more embodiments according to the present invention are also within the scope of the description of this document.

[0026] In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", and "third" may explicitly or implicitly include at least one of the features.

[0027] Figure 1 FIG. 1 is a schematic diagram of a structure of an embodiment of a reconfigurable bidirectional transceiver circuit of the present invention, wherein the direction of the arrow in the figure is the direction of signal flow. Figure 1 It can be seen that the bidirectional transceiver circuit may include a pre-driver, a main transmitter (the transmitter may also be called a driver), a replica transmitter and a signal separation circuit. The pre-driver is located upstream of the main transmitter, the replica transmitter and the signal separation circuit, and is used to drive the main transmitter and the replica transmitter to send a forward signal; the forward signal includes a first forward signal and a second forward signal, the replica transmitter is connected in parallel to the main transmitter, the main transmitter and the replica transmitter are used to send the first forward signal and the second forward signal respectively, and the second forward signal is a replica signal of the first forward signal; the signal separation circuit is located downstream of the main transmitter and the replica transmitter, and is used to separate the reverse signal through the first forward signal and the second forward signal.

[0028] Specifically, in Figure 1In the structure of the example shown, the transmitter and the replica transmitter have the same structure, both including a first power supply power1, a second power supply power2, a first inverter PI1, a second inverter PI2, a first variable resistor RV1, a second variable resistor RV2, a first current mirror CM1 and a second current mirror CM2, the first variable resistor RV1 is connected in parallel with the first inverter PI1, the output end of the first power supply power1 is connected to the input end of the first inverter PI1, the output end of the first inverter PI1 is connected to the output end of the first current mirror CM1, the second variable resistor RV2 is connected in parallel with the second inverter PI2, the output end of the second power supply power2 is connected to the input end of the second inverter PI2, and the output end of the second inverter PI2 is connected to the output end of the second current mirror CM2.

[0029] Two resistors connected in series are connected between the output of the first inverter PI1 and the output of the second inverter PI2 of the replica transmitter (which can be considered as one resistor, and here is a differential drawing method), which is used to simulate the load resistance of the main transmitter, so that the output waveform of the replica transmitter will be consistent with the output waveform of the main transmitter. The output of the main transmitter will be connected to the load resistance, Figure 1 The external parts of the main transmitter are not shown.

[0030] See also Figure 1 and Figure 2 Compared with the commonly used voltage mode transmitter, the output of the transmitter of the present invention is a TIA structure based on an inverter, and two upper and lower dual current mirrors are added. The load of the TIA structure can increase the bandwidth of the driver output, allowing the driver to transmit data at a faster rate. Figure 2 The output swing of the structure shown is not configurable and is half of the power supply voltage, i.e. VDD / 2, which limits its application. In scenarios where the channel insertion loss is large, a larger swing is required. In scenarios where the channel insertion loss is small or there are requirements for electromagnetic radiation, a smaller output swing is required. Figure 2 The structure shown cannot meet the application requirements of multiple scenarios because the output swing is fixed. Figure 1 The structure in the figure can adjust the voltage mode transmitter swing by introducing upper and lower dual current mirrors. When there is no current mirror, the output swing is the circuit output resistance R output and load resistance R load The voltage division of the power supply voltage VDD, that is, VDD*R load / (R output +R load ), usually in impedance matching, R load =R output =R, so the swing is VDD / 2, where R refers to the output impedance of the transmitter R output , load impedance R loadWhen there are upper and lower current mirrors, the current mirror will output or draw an additional current I, so the swing after adding the current mirror is VDD / 2±IR, where I is the current mirror output current and R is the transmitter load resistance.

[0031] When the output swing is VDD / 2+IR, the current mirror output current flows in the same direction as the voltage mode transmitter output current, such as Figure 3a As shown; when the output swing is VDD / 2, the current mirror output current is 0, as shown Figure 3b As shown; when the output swing is VDD / 2-IR, the current mirror output current flows in the opposite direction to the voltage mode transmitter output current, as shown Figure 3c This new structure retains the advantage of low power consumption of the original structure, while the output amplitude is flexible and configurable, which can cover more application scenarios.

[0032] In order to realize the selective use of the replica transmitter, that is, to realize that the entire bidirectional transceiver circuit can operate in a dual-channel mode of reception and transmission, or a separate reception or transmission mode, a second switch SW2-2 is connected between the first power supply power1 input terminal of the main transmitter and the second power supply power2 input terminal of the replica transmitter, and a second switch SW2-1 is connected between the second power supply power2 input terminal of the main transmitter and the first power supply power1 input terminal of the replica transmitter. The second switch SW2-1 and the second switch SW2-2 both refer to second switches, which are controlled by the switch control signal SW2.

[0033] Please continue reading Figure 1 The signal separation circuit includes a first RC unit RC1, a second RC unit RC2, a third RC unit RC3, a fourth RC unit RC4, a fourth switch 1 SW4-1, a fourth switch 2 SW4-2 and a third switch SW3. The capacitor end of the first RC unit RC1 is connected to the output end of the first inverter PI1 of the replica transmitter, the resistor end of the first RC unit RC1 is connected to one end of the fourth switch 1 SW4-1, the other end of the fourth switch 1 SW4-1 is connected to the resistor end of the third RC unit RC3, and the capacitor end of the third RC unit RC3 is connected to the output end of the first inverter PI1 of the main transmitter; the capacitor end of the second RC unit RC2 is connected to the output end of the second inverter PI2 of the replica transmitter, the resistor end of the second RC unit RC2 is connected to one end of the fourth switch 2 SW4-2, the other end of the fourth switch 2 SW4-2 is connected to the resistor end of the fourth RC unit RC4, the capacitor end of the fourth RC unit RC4 is connected to the output end of the second inverter PI2 of the main transmitter, and the third switch SW3 is connected between the fourth switch 1 SW4-1 and the fourth switch 2 SW4-2. The fourth switch 1 SW4 - 1 and the fourth switch 2 SW4 - 2 both refer to fourth switches and are controlled by the switch control signal SW4 .

[0034] The first RC unit RC1, the second RC unit RC2, the third RC unit RC3, and the fourth RC unit RC4 are all composed of a resistor and a capacitor in series. The resistor is used to separate the reverse signal. The advantage of arranging the capacitor is to isolate the influence of the replica drive transmission on the DC bias of the main transmitter, thereby not affecting the output state of the main transmitter.

[0035] The function of the signal separation circuit is to separate the external reverse signal from the port. For differential applications, it supports reverse input common mode and differential signals. The signal separation circuit requires the output signals of the main transmitter and the replica transmitter as input at the same time. At this time, the signal separation module is four equal resistors and capacitors. The function of the capacitor is to isolate the DC bias of the main transmitter and the replica transmitter, and the resistor is used to extract the common mode. At this time, the separated reverse signal V_rep is the common mode of Vop and Von_re, and V_ren is the common mode of Von and Vop_re. For single-ended applications, the replica transmitter can be turned off. In this application, the input of the signal separation circuit only requires the output of the main transmitter. At this time, the reverse signal separated by the signal is vop and von to take the common mode.

[0036] Please continue reading Figure 1 The pre-driver includes a first pre-driver pre1 and a second pre-driver pre2, wherein the output end of the first pre-driver pre1 is connected to one end of the first switch SW1-1, the other end of the first switch SW1-1 is connected to the first power supply power1 input end of the main transmitter and the second power supply power2 input end of the replica transmitter, and the output end of the second pre-driver pre2 is connected to one end of the first switch SW1-2, the other end of the first switch SW1-2 is connected to the second power supply power2 input end of the main transmitter and the first power supply power1 input end of the replica transmitter. The first switch SW1-1 and the first switch SW1-2 are both first switches, which are controlled by the switch control signal SW1.

[0037] like Figure 1 As shown, the other end of the first switch SW1-1 is also connected to the second switch SW2-2, and the second switch SW2-2 is connected between the first power supply power1 input terminal of the main transmitter and the second power supply power2 input terminal of the replica transmitter; the other end of the first switch SW1-2 is also connected to the second switch SW2-1, and the second switch SW2-1 is connected between the second power supply power2 input terminal of the main transmitter and the first power supply power1 input terminal of the replica transmitter.

[0038] The switch signal configuration module is used to output a first switch control signal, a second switch control signal, a third switch control signal, and a fourth switch control signal. The first switch control signal, the second switch control signal, the third switch control signal, and the fourth switch control signal are used to control the opening or closing of the first switch, the second switch, the third switch, and the fourth switch, respectively. The switch signal configuration module cooperates with the first switch, the second switch, the third switch, and the fourth switch to realize the operation of the entire bidirectional transceiver circuit in multiple modes.

[0039] The switch signal configuration module outputs four switch control signals SW1, SW2, SW3, and SW4. Among them, SW1 controls the on and off of the pre-driver output, SW2 controls the on and off of the replica transmitter input, and SW3 and SW4 control the selection of the signal separation mode in the signal separation module. When the circuit is in a double-ended application, switches SW1-1, SW1-2, SW2-1, and SW2-2 are closed. If the reverse signal is a differential signal, switch SW3 is open, and SW4-1 and SW4-2 are closed; if the reverse signal is a common-mode signal, switch SW3 is closed, and SW4-1 and SW4-2 are open. When the circuit is in a single-ended application, SW1-1, SW1-2, and SW3 are closed, and SW2-1, SW2-2, SW4-1, and SW4-2 are open. When the circuit is in a single-ended application, SW1-1 and SW1-2 are closed, and SW2-1, SW2-2, SW3, SW4-1, and SW4-2 are open. When the circuit is in a single-ended transmission mode, SW1-1 and SW1-2 are closed, and SW2-1, SW2-2, SW3, SW4-1, and SW4-2 are open. When the circuit is in single receiving mode, SW1-1, SW1-2, SW2-1, and SW2-2 are disconnected. If the input is a differential signal, SW3 is disconnected, and SW4-1 and SW4-2 are closed. If the input is a single-ended signal, SW3 is closed, and SW4-1 and SW4-2 are disconnected.

[0040] The above-described embodiments are only specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications, replacements and improvements within the technical scope disclosed by the present invention, and these modifications, replacements and improvements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A reconfigurable bidirectional transceiver circuit, comprising a main transmitter and a replica transmitter, wherein the main transmitter is used to transmit a first forward signal, the replica transmitter is connected in parallel to the main transmitter, and the replica transmitter is used to transmit a second forward signal, and the main transmitter and the replica transmitter have the same structure; characterized in that: The main transmitter includes a first power supply, a second power supply, a first inverter, a second inverter, a first variable resistor, a second variable resistor, a first current mirror and a second current mirror, the first variable resistor is connected in parallel with the first inverter, the output end of the first power supply is connected to the input end of the first inverter, the output end of the first inverter is connected to the output end of the first current mirror, the second variable resistor is connected in parallel with the second inverter, the output end of the second power supply is connected to the input end of the second inverter, and the output end of the second inverter is connected to the output end of the second current mirror.

2. The reconfigurable bidirectional transceiver circuit according to claim 1, characterized in that: It also includes a signal separation circuit, wherein the output end of the main transmitter and the output end of the replica transmitter are respectively connected to the input end of the signal separation circuit, and the signal separation circuit is used to separate the reverse signal through the first forward signal.

3. The reconfigurable bidirectional transceiver circuit according to claim 2, characterized in that: The signal separation circuit includes a first RC unit, a second RC unit, a third RC unit, a fourth RC unit and a third switch. The first RC unit, the second RC unit, the third RC unit and the fourth RC unit are all composed of a resistor and a capacitor connected in series. The capacitor end of the first RC unit is connected to the first inverter output end of the replica transmitter, the resistor end of the first RC unit is connected to the resistor end of the third RC unit, and the capacitor end of the third RC unit is connected to the first inverter output end of the main transmitter; the capacitor end of the second RC unit is connected to the second inverter output end of the replica transmitter, the resistor end of the second RC unit is connected to the resistor end of the fourth RC unit, and the capacitor end of the fourth RC unit is connected to the second inverter output end of the main transmitter. The third switch is connected between the fourth switch 1 and the fourth switch 2.

4. The reconfigurable bidirectional transceiver circuit according to claim 3, characterized in that: The system also includes a pre-driver, which is located upstream of the main transmitter and the replica transmitter, and is used to drive the main transmitter and the replica transmitter to transmit a first forward signal and a second forward signal respectively.

5. The reconfigurable bidirectional transceiver circuit according to claim 4, characterized in that: The pre-driver includes a first pre-driver and a second pre-driver, wherein the output end of the first pre-driver is connected to the first power input end of the main transmitter and the second power input end of the replica transmitter, and the output end of the second pre-driver is connected to the second power input end of the main transmitter and the first power input end of the replica transmitter.

6. The reconfigurable bidirectional transceiver circuit according to claim 5, characterized in that: The output end of the first pre-driver is connected to the first power input end of the main transmitter and the first power input end of the replica transmitter through the first switch 1, and the output end of the second pre-driver is connected to the second power input end of the main transmitter and the second power input end of the replica transmitter through the first switch 2; the second switch 2 is connected between the first power input end of the main transmitter and the second power input end of the replica transmitter, and the second switch 1 is connected between the second power input end of the main transmitter and the first power input end of the replica transmitter; the resistance end of the first RC unit is connected to the resistance end of the third RC unit through the fourth switch 1, and the resistance end of the second RC unit is connected to the resistance end of the fourth RC unit through the fourth switch 2; The reconfigurable bidirectional transceiver circuit further includes a switch signal configuration module for outputting a first switch control signal, a second switch control signal, a third switch control signal, and a fourth switch control signal.

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