TWI669918B - Transmission circuit with adaptive sender equalizer adjustment function and communication device using the same - Google Patents

Abstract

A transmission circuit with an adaptive equalizer adjustment function at a transmitting end, which has a feedforward equalizer and a receive equalizer at a transmitting end and a receiving end of a differential transmission channel, respectively. : An adaptive compensation adjustment module for performing a pseudo bit error rate operation on an output voltage signal of the receiving equalizer to generate a common-mode voltage control signal; a common-mode voltage generating module for using the common mode The voltage control signal generates a common-mode voltage and couples the common-mode voltage to the differential transmission channel; and a common-mode voltage detection module for transmitting the common-mode voltage and a reference voltage according to one of the differential transmission channels. A comparison result generates a feedback signal, and the feedback signal is transmitted to the feedforward equalizer to adjust a gain frequency response distribution or a compensation voltage of the feedforward equalizer.

Description

Transmission circuit with adaptive sender equalizer adjustment function and communication device using the same

The present invention relates to an equalizer adjustment circuit at the transmitting end, and more particularly to a transmission circuit with an adaptive equalizer adjustment function at the transmission end for realizing a high-speed transmission interface circuit.

In high-speed serial data communication, due to the influence of channel attenuation and skin effects, the receiving end data will be subject to severe inter-symbol interference (ISI).

In order to solve the problem of inter-symbol interference, a common method is to compensate channel attenuation by an equalizer at the receiving end of the serial data. For example, a decision feedback equalizer is used to eliminate inter-symbol interference. However, due to the uncertainty of the channel attenuation amplitude and the equalizer's process deviation, the compensation circuit is prone to under- or over-compensation, which results in a smaller data recovery margin at the receiving end.

The existing compensation modes generally include: method (1) agreement compensation adjustment between the sender and receiver after power-on; method (2) self-adjustment by detecting the proportional relationship between the high-frequency and low-frequency components of the compensated data-a continuous-time linear equalizer And method (3) self-adjusting channel compensation based on least squares. However, method (1) requires a secondary channel to complete, method (2) requires a complex spectrum detection circuit, and method (3) requires complex calculations.

In order to solve the above problems, a novel equalizer compensation circuit is urgently needed in the art.

An object of the present invention is to disclose a transmission circuit with an adaptive equalizer adjustment function at the transmitting end, which can use an adaptive compensation adjustment module located at the receiving end to adjust the compensation parameters of an equalizer at the transmitting end, thereby being fast and accurate The compensation of the one-channel attenuation effect.

Another object of the present invention is to disclose a transmission circuit with an adaptive equalizer adjustment function at the transmitting end, which can adjust a differential transmission common-mode voltage to adjust a transmitting end, etc. using an adaptive compensation adjustment module located at the receiving end. Compensation parameters of the modulator, thereby quickly and accurately eliminating the phenomenon of intersymbol interference of data signals.

Another object of the present invention is to disclose a transmission circuit with an adaptive equalizer adjustment function at the transmitting end. The adaptive compensation adjustment module located at the receiving end can be used to adjust the compensation parameters of an equalizer at the transmitting end. Accurately correct the influence of circuit parameters due to process deviation.

Another object of the present invention is to disclose a transmission circuit with an adaptive equalizer adjustment function at the transmitting end, which can turn off an adaptive compensation adjustment module after one compensation adjustment is completed to save power consumption.

In order to achieve the foregoing object, a transmission circuit having an adaptive equalizer adjustment function at the transmitting end is proposed, which has: a feedforward equalizer, having a signal input terminal for receiving a transmission data signal, and a feedback input terminal for Receiving a feedback signal and a signal output terminal to provide a transmission voltage signal, the feedback signal is used to adjust a gain frequency response distribution or a compensation voltage of the feedforward equalizer; a driving unit having an input terminal To receive the transmitted voltage signal, and two output terminals to output a differential voltage signal to a differential transmission channel; a receiving equalizer having a positive receiving terminal, a negative receiving terminal and an output terminal, wherein the positive The receiving end and the negative receiving end are used for coupling with the differential transmission channel to receive a differential input voltage signal, and the output end is used for providing an output voltage signal; an adaptive compensation adjustment module having a An input terminal receives the output voltage signal, and an output terminal provides a common-mode voltage control signal, and is used to perform a pseudo bit error rate operation on the output voltage signal to produce The common mode voltage control signal; a common mode voltage generating module for generating a common mode voltage according to the common mode voltage control signal, and coupling the common mode voltage to the differential transmission channel; and a common mode voltage detection module Having an input terminal coupled to the differential transmission channel to receive a transmission common-mode voltage, and an output terminal to provide the feedback signal, and is used to transmit the common-mode voltage and a first reference voltage according to A comparison results in the feedback signal.

In one embodiment, the adaptive compensation adjustment module has: a first comparator having a first positive input terminal, a first negative input terminal, a first control terminal and a A first output terminal, the first positive input terminal is coupled to the output terminal, the first negative input terminal is coupled to a second reference voltage, and the first control terminal is coupled to a data clock signal; The second comparator has a second positive input terminal, a second negative input terminal, a second control terminal, and a second output terminal. The second positive input terminal is coupled to the output terminal and the second negative terminal. The input terminal is coupled to the second reference voltage, the second control terminal is coupled to an auxiliary clock signal, and there is a phase difference between the auxiliary clock signal and the data clock signal; a mutually exclusive OR operation unit having A first input terminal, a second input terminal, and a third output terminal, the first input terminal is coupled to the first output terminal, and the second input terminal is coupled to the second output terminal; and The pseudo bit error rate calculation module has a bit data input terminal, a third control terminal and a feedback output terminal. The bit data input terminal is coupled with the third output terminal, and the third control terminal is connected with A system clock signal is coupled, and the feedback output terminal is used to output the common mode voltage. Control signal, wherein the pseudo bit error rate calculation module is used to generate a pseudo bit error rate calculation for a mutually exclusive or output signal received by the bit data input terminal according to the control of the system clock signal. The common-mode voltage control signal.

In an embodiment, the feedforward equalizer and the receive equalizer are both a continuous-time linear equalizer or a decision feedback equalizer.

In an embodiment, the transmission circuit having an adaptive equalizer adjustment function on the transmitting end further includes an auxiliary clock generating circuit, and the auxiliary clock generating circuit is configured to generate the auxiliary clock signal according to the data clock signal.

In one embodiment, the auxiliary clock generating circuit includes a phase interpolator.

In one embodiment, the auxiliary clock generating circuit includes a delay-locked loop.

In one embodiment, the auxiliary clock generating circuit includes a delay circuit.

In one embodiment, the pseudo bit error rate calculation is performed on the number of pulses of the mutually exclusive or output signal.

That is to say, the transmission circuit with the adaptive equalizer adjustment function of the present invention is provided with a feedforward equalizer and a receive equalizer on a transmitting end and a receiving end of a differential transmission channel, respectively. And it is characterized by having an adaptive compensation adjustment module, having an input terminal to receive an output voltage signal from one of the receiving equalizers, and an output terminal to provide a common-mode voltage control signal, and it is used for The output voltage signal performs a pseudo bit error rate operation to generate the common mode voltage control signal; a common mode voltage generating module is used to generate a common mode voltage according to the common mode voltage control signal, and couple the common mode voltage to The differential transmission channel; and a common-mode voltage detection module having an input terminal coupled to the differential transmission channel to receive a transmission common-mode voltage, and an output terminal to provide a feedback signal to the feedforward equalization The modulator adjusts a gain frequency response distribution or a compensation voltage of the feedforward equalizer, and the common-mode voltage detection module is used to generate a comparison result of the transmitted common-mode voltage and a reference voltage. Feedback signal.

In addition, in order to achieve the foregoing object, the present invention further provides a communication device having a transmission circuit with an adaptive equalizer adjustment function as described above.

In order to enable your reviewers to further understand the structure, characteristics, and purpose of the present invention, drawings and detailed descriptions of the preferred embodiments are attached below.

100‧‧‧ Feedforward Equalizer

110‧‧‧Drive unit

120‧‧‧ differential transmission channel

130‧‧‧ receive equalizer

140‧‧‧Adaptive compensation adjustment module

141‧‧‧first comparator

142‧‧‧Second Comparator

143‧‧‧mutex or arithmetic unit

144‧‧‧False Bit Error Rate Calculation Module

150‧‧‧ Common Mode Voltage Generation Module

151‧‧‧common mode voltage generating unit

152, 153‧‧‧ Coupling resistance

160‧‧‧Common mode voltage detection module

161‧‧‧ Comparator

170‧‧‧ auxiliary clock generation circuit

FIG. 1 is a block diagram of an embodiment of a transmission circuit with an adaptive equalizer adjustment function at the transmitting end according to the present invention.

FIG. 2 is a block diagram of generating an auxiliary clock signal CLK_AUX according to a data clock signal CLK_DATA shown in FIG. 1 using an auxiliary clock generating circuit.

FIG. 3a is an eye diagram generated by a data signal processed by a conventional equalizer.

FIG. 3b is an eye diagram generated by a data signal processed by the technical solution of the present invention.

Please refer to FIG. 1, which illustrates a block diagram of an embodiment of a transmission circuit with an adaptive equalizer adjustment function at the transmitting end according to the present invention.

As shown in FIG. 1, the transmission circuit with an adaptive equalizer adjustment function at the transmitting end includes a feedforward equalizer 100, a drive unit 110, a differential transmission channel 120, a receiving equalizer 130, and a The adaptive compensation adjustment module 140, a common-mode voltage generating module 150, and a common-mode voltage detecting module 160.

The feedforward equalizer 100 may be a continuous-time linear equalizer or a decision feedback equalizer, having a signal input terminal to receive a transmission data signal D _TX , a feedback input terminal to receive a feedback signal FB, and A signal output terminal provides a transmission voltage signal V _TX . The feedback signal FB is used to adjust a gain frequency response distribution or a compensation voltage of the feedforward equalizer 100. Since the continuous time linear equalizer and the decision feedback equalizer are conventional equalizers, they are not intended to be further described here.

The driving unit 110 has an input terminal for receiving the transmission voltage signal V _TX , and two output terminals for outputting a differential voltage signal (TXP, TXN) to the differential transmission channel 120.

The receiving equalizer 130 may be a continuous-time linear equalizer or a decision feedback equalizer, and has a positive receiving end, a negative receiving end, and an output end, wherein the positive receiving end and the negative receiving end are The output terminal is coupled to the differential transmission channel 120 to receive a differential input voltage signal V _in , and the output terminal is used to provide an output voltage signal D _RX .

The adaptive compensation adjustment module 140 has an input terminal to receive the output voltage signal D _RX , and an output terminal to provide a _common- mode voltage control signal V _CMCNTL , and is used to perform a false error on the output voltage signal D _RX . The bit rate is calculated to generate the common-mode voltage control signal V _CMCNTL .

The common mode voltage generating module 150 has a common mode voltage generating unit 151 and two coupling resistors 152 and 153, which are used to generate a common mode voltage V _CM according to the common mode voltage control signal V _CMCNTL and make the common mode voltage V _CM is coupled to the positive and negative transmission lines of the differential transmission channel 120 through two coupling resistors 152 and 153.

The common mode voltage detection module 160 has an input terminal coupled to the differential transmission channel 120 to receive a transmission common mode voltage V _TRCM , and an output terminal to provide the feedback signal FB to adjust the feedforward equalizer 100. A gain frequency response distribution or a compensation voltage, and the common mode voltage detection module 160 is used to compare a transmitted common mode voltage V _TRCM with a first reference voltage V _REF1 according to a comparator 161 This feedback signal FB is generated.

In a possible embodiment, as shown in FIG. 1, the adaptive compensation adjustment module 140 has a first comparator 141, a second comparator 142, a mutually exclusive OR operation unit 143, and a pseudo error rate calculation module. Group 144.

The first comparator 141 has a first positive input terminal, a first negative input terminal, a first control terminal, and a first output terminal. The first positive input terminal is connected to the output terminal of the receiving equalizer 130. Coupling, the first negative input terminal is coupled to a second reference voltage V _REF2 , and the first control terminal is coupled to a data clock signal CLK_DATA.

The second comparator 142 has a second positive input terminal, a second negative input terminal, a second control terminal, and a second output terminal. The second positive input terminal is connected to the output terminal of the receiving equalizer 130. Coupled, the second negative input terminal is coupled to the second reference voltage V _REF2 , the second control terminal is coupled to an auxiliary clock signal CLK_AUX, and the auxiliary clock signal CLK_AUX and the data clock signal CLK_DATA have A phase difference.

The mutex OR operation unit 143 has a first input terminal, a second input terminal, and a third output terminal. The first input terminal is coupled to the first output terminal of the first comparator 141, and the second The input terminal is coupled to the second output terminal of the second comparator 142.

The pseudo bit error rate calculation module 144 has a bit data input terminal, a third control terminal, and a feedback output terminal. The bit data input terminal is coupled to the third output terminal of the mutually exclusive OR operation unit 143. The third control terminal is coupled to a system clock signal CLK_SYS, and the feedback output terminal is used to output the common mode voltage control signal V _CMCNTL , wherein the pseudo bit error rate calculation module 144 is used to The control of the system clock signal CLK_SYS performs a pseudo bit error rate calculation on a mutually exclusive or output signal received by the bit data input terminal to generate the common-mode voltage control signal V _CMCNTL . In a possible embodiment, the calculation of the pseudo bit error rate may be a pulse number counting operation on the mutually exclusive or output signal.

In addition, please refer to FIG. 2, which is a block diagram of using an auxiliary clock generating circuit 170 to generate the auxiliary clock signal CLK_AUX according to the data clock signal CLK_DATA. The auxiliary clock generating circuit 170 may be implemented by a phase interpolator, a delay phase lock A loop or a delay circuit is implemented so that the data clock signal CLK_DATA and the auxiliary clock signal CLK_AUX have an appropriate fixed phase difference so that the adaptive compensation adjustment module 140 provides an accurate compensation function.

In addition, please refer to FIG. 3a and FIG. 3b, which are respectively an eye diagram generated by a data signal processed by a conventional equalizer and an eye diagram generated by a data signal processed by the technical solution of the present invention. It can be seen from FIG. 3a and FIG. 3b that the “eye” part of the eye diagram generated by the data signal processed by the conventional equalizer is smaller, and the eye diagram generated by the data signal processed by the technical solution of the present invention The "eyes" part is larger. Because the inter-symbol interference will make the "eye" part of the eye diagram smaller, it can be seen from Figures 3a and 3b that the technical solution of the present invention can effectively eliminate the symbol generated by the data signal after being transmitted through the communication channel. Inter-symbol interference problem.

In addition, according to the technical effects that can be achieved by the present invention, the adaptive sender equalizer adjustment circuit of the present invention can be applied to V-by-one (a flat panel display signal transmission interface standard) high-speed serial data communication, HDMI (high definition multimedia interface) data communication, EDP (embedded display port) data communication, PCIE (peripheral component interconnect-express) and USB (universal serial bus; universal serial bus) data communication.

With the design disclosed above, the present invention can provide the following advantages:

1. The transmission circuit with the adaptive equalizer adjustment function of the present invention can use an adaptive compensation adjustment module located at the receiving end to adjust the compensation parameters of the equalizer at the transmitting end, thereby quickly and accurately compensating the attenuation of a channel effect.

2. The transmission circuit with an adaptive equalizer adjustment function of the present invention can adjust a differential transmission common-mode voltage to adjust the compensation of an equalizer at the transmitting end by using an adaptive compensation adjustment module located at the receiving end. Parameters, thereby quickly and accurately eliminating the phenomenon of intersymbol interference of data signals.

3. The transmission circuit with the adaptive equalizer adjustment function of the present invention can use an adaptive compensation adjustment module located at the receiving end to adjust the compensation parameters of the equalizer at the transmitting end, thereby quickly and accurately correcting the circuit. Influence of parameters due to process deviation.

4. The transmission circuit with the adaptive equalizer adjustment function of the present invention can turn off an adaptive compensation adjustment module after one compensation adjustment is completed to save power consumption.

What is disclosed in this case is a preferred embodiment. For example, those who have partial changes or modifications that are derived from the technical ideas of this case and are easily inferred by those skilled in the art, do not depart from the scope of patent rights in this case.

To sum up, regardless of the purpose, method and effect, this case is showing its technical characteristics that are quite different from the conventional ones, and its first invention is practical, and it is also in line with the patent requirements of the invention. Granting patents at an early date will benefit society and feel good.

Claims (10)

A transmission circuit with an adaptive equalizer adjustment function at a transmitting end includes: a feedforward equalizer, a signal input terminal to receive a transmission data signal, a feedback input terminal to receive a feedback signal, and a signal An output terminal for providing a transmission voltage signal, the feedback signal is used to adjust a gain frequency response distribution or a compensation voltage of the feedforward equalizer; a driving unit having an input terminal for receiving the transmission voltage signal, and The two output terminals output a differential voltage signal to a differential transmission channel; a receiving equalizer has a positive receiving terminal, a negative receiving terminal and an output terminal, wherein the positive receiving terminal and the negative receiving terminal are It is used for coupling with the differential transmission channel to receive a differential input voltage signal, and the output end is used to provide an output voltage signal; an adaptive compensation adjustment module has an input end to receive the output voltage signal And an output terminal for providing a common-mode voltage control signal, which is used to perform a pseudo bit error rate operation on the output voltage signal to generate the common-mode voltage control signal; A common-mode voltage generating module is configured to generate a common-mode voltage according to the common-mode voltage control signal, and couple the common-mode voltage to the differential transmission channel; and a common-mode voltage detection module having an input terminal to communicate with The differential transmission channel is coupled to receive a transmission common-mode voltage, and an output terminal is provided to provide the feedback signal, and the differential transmission channel is used to generate the feedback signal according to a comparison result between the transmission common-mode voltage and a first reference voltage. . The transmission circuit with an adaptive equalizer adjustment function as described in item 1 of the scope of the patent application, wherein the adaptive compensation adjustment module has: a first comparator having a first positive input terminal, a first A negative input terminal, a first control terminal and a first output terminal, the first positive input terminal is coupled to the output terminal, the first negative input terminal is coupled to a second reference voltage, the first The control terminal is coupled to a data clock signal. A second comparator has a second positive input terminal, a second negative input terminal, a second control terminal and a second output terminal. The second positive input terminal Is coupled to the output terminal, the second negative input terminal is coupled to the second reference voltage, the second control terminal is coupled to an auxiliary clock signal, and the auxiliary clock signal and the data clock signal have A phase difference; a mutually exclusive OR operation unit having a first input terminal, a second input terminal and a third output terminal, the first input terminal is coupled to the first output terminal, and the second input terminal Is coupled to the second output terminal; and a pseudo bit error rate calculation module Has a bit data input terminal, a third control terminal and a feedback output terminal, the bit data input terminal is coupled to the third output terminal, and the third control terminal is coupled to a system clock signal, The feedback output terminal is used to output the common-mode voltage control signal, wherein the pseudo bit error rate calculation module is used to control an interaction received by the bit data input terminal according to the control of the system clock signal. Reject or output the signal to perform a pseudo bit error rate calculation to generate a common-mode voltage control signal. The transmission circuit with an adaptive equalizer adjustment function as described in item 1 of the scope of patent application, wherein the feedforward equalizer and the receive equalizer are both a continuous time linear equalizer or a decision feedback Equalizer. The transmission circuit with an adaptive equalizer adjustment function according to item 2 of the scope of the patent application, further comprising an auxiliary clock generating circuit, which is used to generate the auxiliary clock according to the data clock signal. signal. The transmission circuit with an adaptive equalizer adjustment function as described in item 4 of the patent application scope, wherein the auxiliary clock generating circuit includes a phase interpolator. The transmission circuit with an adaptive equalizer adjustment function as described in item 4 of the patent application scope, wherein the auxiliary clock generating circuit includes a delay phase locked loop. The transmission circuit with an adaptive equalizer adjustment function as described in item 4 of the scope of the patent application, wherein the auxiliary clock generating circuit includes a delay circuit. The transmission circuit with an adaptive equalizer adjustment function as described in item 2 of the scope of the patent application, wherein the pseudo bit error rate calculation is performed on the number of pulses of the mutually exclusive or output signal. A transmission circuit with an adaptive equalizer adjustment function at a transmitting end, which has a feedforward equalizer and a receive equalizer at a transmitting end and a receiving end of a differential transmission channel, respectively. : An adaptive compensation adjustment module having an input terminal for receiving an output voltage signal from one of the receiving equalizers, and an output terminal for providing a common-mode voltage control signal, which is used to perform a A pseudo bit error rate operation to generate the common mode voltage control signal; a common mode voltage generating module for generating a common mode voltage according to the common mode voltage control signal, and coupling the common mode voltage to the differential transmission channel; And a common-mode voltage detection module having an input terminal coupled to the differential transmission channel to receive a transmission common-mode voltage, and an output terminal to provide a feedback signal to the feed-forward equalizer to adjust the feed-forward One of the equalizers has a gain frequency response distribution or a compensation voltage, and the common mode voltage detection module is configured to generate the feedback signal according to a comparison result of the transmitted common mode voltage and a reference voltage. A communication device has a transmission circuit with an adaptive equalizer adjustment function at the transmitting end as described in any one of claims 1 to 9.