阅读说明：本技术 串行器/解串器实体层电路 (Serializer/deserializer physical layer circuit ) 是由 刘剑 管继孔 于 2018-06-13 设计创作，主要内容包括：一种串行器/解串器实体层电路,能以半双工的方式接收及传送数据,该串行器/解串器实体层电路包含：时钟倍频单元,包含相位频率检测器、电荷泵、低通滤波器、压控振荡器、以及回路除法器；采样电路,于接收模式下依据压控振荡器输出的采样时钟采样接收信号；相位检测器,依据采样电路的输出运行；多工器,于接收模式下电性连接相位检测器与电荷泵及电性断开相位频率检测器与电荷泵,令压控振荡器产生两个采样时钟,多工器还于传送模式下电性连接相位频率检测器与电荷泵及电性断开相位检测器与电荷泵,令压控振荡器产生输出时钟；并串转换器,依据输出时钟将并行数据转换成串行数据；以及传送驱动器,于传送模式下依据串行数据输出传送信号。(A serializer/deserializer phy-layer circuit capable of receiving and transmitting data in a half-duplex manner, the serializer/deserializer phy-layer circuit comprising: the clock frequency multiplication unit comprises a phase frequency detector, a charge pump, a low-pass filter, a voltage-controlled oscillator and a loop divider; the sampling circuit samples a receiving signal according to a sampling clock output by the voltage-controlled oscillator in a receiving mode; a phase detector operating in accordance with an output of the sampling circuit; a multiplexer electrically connecting the phase detector and the charge pump and electrically disconnecting the phase frequency detector and the charge pump in a receiving mode to enable the voltage-controlled oscillator to generate two sampling clocks, and electrically connecting the phase frequency detector and the charge pump and electrically disconnecting the phase detector and the charge pump in a transmitting mode to enable the voltage-controlled oscillator to generate an output clock; a parallel-to-serial converter for converting the parallel data into serial data according to an output clock; and a transmission driver for outputting a transmission signal according to the serial data in a transmission mode.)

1. A serializer/deserializer physical layer circuit comprising:

a clock frequency multiplication unit, including a phase frequency detector, a charge pump, a low pass filter, a voltage controlled oscillator, and a loop divider, wherein the voltage controlled oscillator is used for outputting at least one sampling clock in a receiving mode and outputting an output clock in a transmitting mode;

a sampling circuit, coupled to the vco and a data input, for sampling according to the at least one sampling clock and a received signal at the data input;

a phase detector coupled to the sampling circuit;

a multiplexer for electrically connecting the phase detector and the charge pump and electrically disconnecting the phase frequency detector and the charge pump in the receiving mode, so that the voltage controlled oscillator outputs the at least one sampling clock in the receiving mode, the multiplexer further for electrically connecting the phase frequency detector and the charge pump and electrically disconnecting the phase detector and the charge pump in the transmitting mode, so that the voltage controlled oscillator outputs the output clock in the transmitting mode;

a parallel-to-serial converter for converting parallel data into serial data according to the output clock; and

a transmission driver for outputting a transmission signal according to the serial data in the transmission mode.

2. The serializer/deserializer physical layer circuit of claim 1 wherein in the receive mode at least one of the pfd, the parallel-to-serial converter and the transmit driver is disabled.

3. The serializer/deserializer physical layer circuit of claim 2 wherein at least one of the sampling circuit and the phase detector is disabled in the transmit mode.

4. The serializer/deserializer physical layer circuit of claim 1 wherein at least one of the sampling circuit and the phase detector is disabled in the transmit mode.

5. The serializer/deserializer physical layer circuit of claim 1 further comprising an input/output circuit, the input/output circuit comprising:

a positive-side input/output pad;

a negative terminal input/output pad;

a positive terminal impedance coupled between the positive input/output pad and a negative terminal impedance;

the negative terminal impedance is coupled between the positive terminal impedance and the negative input/output pad;

a positive terminal switch including a first terminal coupled to the positive terminal input/output pad and the positive terminal impedance, and a second terminal coupled to the sampling circuit; and

a negative terminal switch including a third terminal coupled to the negative terminal I/O pad and the negative terminal impedance, and a fourth terminal coupled to the sampling circuit,

wherein the transmit driver is coupled to the I/O circuit and disabled in the receive mode; the positive terminal switch and the negative terminal switch are turned on in the reception mode and turned off in the transmission mode.

6. The serializer/deserializer physical layer circuit of claim 5 wherein the positive terminal impedance comprises a positive inductor and a positive resistor and the negative terminal impedance comprises a negative inductor and a negative resistor.

7. The serializer/deserializer physical layer circuit of claim 6 wherein an impedance value of the positive end termination impedance is equal to an impedance value of the negative end termination impedance.

8. The serializer/deserializer physical layer circuit of claim 5 wherein the transmit driver comprises:

a first positive terminal current source;

a first positive terminal transistor coupled between the first positive terminal current source and the positive terminal input/output pad, the first positive terminal transistor being turned off in the reception mode and turned on in the transmission mode;

a second positive terminal current source;

a second positive terminal transistor coupled between the second positive terminal current source and the positive terminal input/output pad, the second positive terminal transistor being turned off in the reception mode and turned on in the transmission mode;

a first negative terminal current source;

a first negative side transistor coupled between the first negative side current source and the negative side input/output pad, the first negative side transistor being turned off in the reception mode and turned on in the transmission mode;

a second negative terminal current source; and

a second negative side transistor coupled between the second negative side current source and the negative side input/output pad, the second negative side transistor being turned off in the receive mode and turned on in the transmit mode.

9. The serializer/deserializer physical layer circuit of claim 8 wherein the first positive current source, the second positive current source, the first negative current source and the second negative current source are disabled in the receive mode and enabled in the transmit mode.

10. The serializer/deserializer physical layer circuit of claim 1 applied to a Universal Serial Bus (USB) type C device.

Technical Field

The present invention relates to physical layer circuits, and more particularly to serializer/deserializer physical layer circuits.

Background

Conventional Serializer/Deserializer (SerDes) physical layer circuitry includes separate receive and transmit circuitry for performing serial data receive and transmit functions, respectively. The receiving circuit may employ the analog Clock Data Recovery (CDR) circuit 100 of fig. 1, which includes a Data Sampler (DS) 110, an Edge Sampler (ES) 120, a Phase Detector (PD) 130, a Charge Pump (CP) 140, a Low Pass Filter (LPF) 150, and a voltage-controlled oscillator (VCO) 160. The transmission circuit may adopt the transmission circuit 200 of fig. 2, which includes a Clock Multiplication Unit (CMU) 210, a parallel-to-serial converter 220, and a transmission driver 230, wherein the clock multiplication unit 210 includes a Phase Frequency Detector (PFD) 212, a charge pump 214, a low pass filter 216, a voltage controlled oscillator 218, and a Loop Divider (LD) 219. As can be seen from the above, the conventional SerDes phy layer circuit includes two repeated/similar circuits, such as two charge pumps, two low pass filters, and two voltage controlled oscillators, in order to implement the receiving function and the transmitting function, which results in a large circuit area, is not favorable for circuit miniaturization, and is not cost-effective.

Disclosure of Invention

It is an object of the present invention to provide an apparatus and method to avoid the problems of the prior art.

The invention discloses a serializer/deserializer physical layer circuit, which can receive and transmit data in a Half Duplex (Half Duplex) mode. The clock frequency multiplication unit comprises a phase frequency detector, a charge pump, a low pass filter, a voltage controlled oscillator and a loop divider, wherein the voltage controlled oscillator is used for outputting at least one sampling clock (for example, two clocks with the same frequency but different phases) in a receiving mode and outputting an output clock in a transmitting mode. The sampling circuit is coupled to the voltage-controlled oscillator, a data input terminal and a data output terminal, and is configured to perform sampling according to the at least one sampling clock and a received signal of the data input terminal, so as to output a sampling signal to the data output terminal. The phase detector is used for performing phase detection according to the output of the sampling circuit. The multiplexer is used for electrically connecting the phase detector and the charge pump and electrically disconnecting the phase frequency detector and the charge pump in the receiving mode, so that the voltage-controlled oscillator outputs the at least one sampling clock in the receiving mode; the multiplexer is further configured to electrically connect the phase frequency detector and the charge pump and electrically disconnect the phase detector and the charge pump in the transmission mode, so that the voltage controlled oscillator outputs the output clock in the transmission mode. The parallel-serial converter is used for converting parallel data into serial data according to the output clock. The transmission driver is used for outputting a transmission signal according to the serial data in the transmission mode.

The features, implementations, and technical advantages of the present invention are described in detail below with reference to the accompanying drawings.

Drawings

FIG. 1 illustrates an analog clock data recovery circuit employed by a receiving circuit of a prior art serializer/deserializer physical layer circuit;

FIG. 2 shows a prior art transmit circuit of a serializer/deserializer physical layer circuit;

FIG. 3 illustrates one embodiment of a serializer/deserializer physical layer circuit of the present invention;

FIG. 4 shows an embodiment of the clock multiplier unit of FIG. 3;

FIG. 5 illustrates one embodiment of the sampling circuit of FIG. 3;

FIG. 6 illustrates an embodiment of an input/output circuit of the serializer/deserializer physical layer circuit of the present invention;

FIG. 7 shows an embodiment of the positive terminal impedance and the negative terminal impedance of FIG. 6; and

FIG. 8 shows an embodiment of a transmit driver coupled to the input/output circuit of FIG. 6.

Description of the symbols

100 analog clock data recovery circuit

110 DS (data sampler)

120 ES (edge sampler)

130 PD (phase detector)

140 CP (Charge Pump)

150 LPF (Low pass filter)

160 VCO (Voltage controlled Oscillator)

200 transfer circuit

210 clock frequency multiplication unit

212 PFD (phase frequency detector)

214 CP (Charge Pump)

216 LPF (Low pass filter)

218 VCO (Voltage controlled oscillator)

219 LD (Loop divider)

220 parallel-serial converter

230 transfer driver

300 serializer/deserializer physical layer circuit

310 CMU (clock frequency multiplication unit)

320 SC (sampling circuit)

330 PD (phase detector)

340 MUX (multiplexer)

350 parallel-serial converter

360 transfer driver

410 PFD (phase frequency detector)

420 CP (Charge pump)

430 LPF (Low pass filter)

440 VCO (Voltage controlled oscillator)

450 LD (Loop divider)

F_REFReference clock

F_DIVFrequency-eliminating clock

F_VCOOutput clock

510 DS (data sampler)

520 ES (edge sampler)

CKI and CKQ sampling clock

600 input/output circuit

610 positive terminal input/output pad

620 negative terminal input/output pad

630 Z_P(Positive terminal impedance)

640 Z_N(negative terminal impedance)

650 positive terminal switch

660 negative terminal switch

710 positive terminal inductor

720 positive terminal resistor

730 negative terminal inductor

740 negative terminal resistance

V_CMCommon mode voltage

810 first positive terminal current source

820 first positive terminal transistor

830 second positive terminal current source

840 second positive terminal transistor

850 first negative terminal current source

860 first negative terminal transistor

870 second negative terminal current source

880 second negative terminal transistor

V_DDHigh potential

GND low potential

Detailed Description

The terms in the following description refer to the conventional terms in the field, and some terms are defined or explained in the specification, and are to be interpreted according to the description or the definition of the specification.

The present disclosure includes a Serializer/Deserializer physical layer circuit (SerDes PHY) capable of receiving and transmitting data in a half-duplex manner, which integrates a receiving circuit and a transmitting circuit in a common circuit manner, thereby avoiding circuit area waste and achieving circuit miniaturization and high cost efficiency.

Fig. 3 shows an embodiment of the present invention applied to a Universal Serial Bus (USB) Type C (Type-C) device or other devices requiring a serializer/deserializer physical layer circuit. The serializer/deserializer phy layer circuit 300 of fig. 3 includes a Clock Multiplication Unit (CMU) 310, a Sampling Circuit (SC) 320, a Phase Detector (PD) 330, a Multiplexer (MUX) 340, a parallel-to-serial converter (P-to-S converter)350, and a transmit driver (TXdriver) 360.

Please refer to fig. 3. An embodiment of the clock frequency multiplier unit 310 is shown in fig. 4, and includes a Phase Frequency Detector (PFD) 410, a Charge Pump (CP) 420, a Low Pass Filter (LPF) 430, a voltage-controlled oscillator (VCO) 440, and a Loop Divider (LD) 450. The PFD 410 is used for detecting a reference clock F_REFAnd a frequency-dividing clock F_DIVThe difference between them, outputs a phase frequency detection signal to the multiplexer 340. The charge pump 420 is used for generating a voltage control signal according to a multiplexer output signal of the multiplexer 340 (i.e. the phase frequency detection signal of the phase frequency detector 410 or a phase detection signal of the phase detector 330). The low pass filter 430 is used for determining an input voltage according to the voltage control signal. The VCO 440 is used for generating at least one sampling clock (e.g., two clocks CKI, CKQ having the same frequency and a phase difference of ninety degrees) according to the input voltage in a receiving mode, or a single clock for the sampling circuit 320 to generate the two clocks CKI, CKQ), and for generating an output clock F according to the input voltage in a transmitting mode_VCO. The loop divider 450 is used for outputting the clock F according to the output clock_VCOPerforming frequency division to generate the frequency division clock F_DIV(ii) a For example, the frequency-divided clock F_DIVIs not more than the output clock F_VCOOr the divided clock F_DIVShould have a frequency substantially equal to the output clock F_VCOOf (c) is detected. Each of phase frequency detector 410, charge pump 420, low pass filter 430, voltage controlled oscillator 440, and loop divider 450 may be implemented by known techniques.

Please refer to fig. 3. One embodiment of the sampling circuit 320 is shown in fig. 5, and includes a Data Sampler (DS) 510 and an Edge Sampler (ES) 520. The data sampler 510 and the edge sampler 520 are coupled to the vco 440 and a data input end, for sampling a received signal at the data input end according to two sampling clocks (CKI, CKQ, having the same frequency and a phase difference of ninety degrees) of the vco 440, respectively; the data sampler 510 is further coupled to a data output terminal for outputting a sampling signal to the data output terminal according to the sampling result. Each of the data sampler 510 and the edge sampler 520 may be implemented by known techniques.

Please refer to fig. 3. The phase detector 330 is used for performing phase detection according to the output of the sampling circuit 320 to output the phase detection signal to the multiplexer 340; for example, the phase detector 330 outputs the phase detection signal to the multiplexer 340 by performing a logic operation according to the output of the data sampler 510 and the output of the edge sampler 520. Phase detector 330 may be implemented by known techniques.

Please refer to fig. 3. In the receiving mode, the multiplexer 340 is used to electrically connect the phase detector 330 and the charge pump 420, and electrically disconnect the pfd 410 and the charge pump 420, so that the charge pump 420 generates the voltage control signal according to the phase detection signal of the phase detector 330, the low pass filter 430 generates the input voltage according to the voltage control signal, and the vco 440 outputs the at least one sampling clock according to the input voltage. In the transmission mode, the multiplexer 340 is used to electrically connect the phase frequency detector 410 and the charge pump 420 and electrically disconnect the phase detector 330 and the charge pump 420, so that the charge pump 420 generates the voltage control signal according to the phase frequency detection signal of the phase frequency detector 410, the low pass filter 430 generates the input voltage according to the voltage control signal, and the voltage controlled oscillator 440 outputs the output clock F according to the input voltage_VCO. The multiplexer 340 may be implemented by known techniques. It is noted that multiplexer 340 operates in one of the receiving mode and the transmitting mode according to a control signal; since the control signal can be generated by known techniques, the details of the control signal are omitted here.

Please refer to fig. 3. The parallel-to-serial converter 350 is used for outputting the clock F according to the VCO 440 in the transmission mode_VCOConverting the parallel data into serial data,wherein the transmission frequency of the parallel data is not higher than the transmission frequency of the serial data; the parallel-to-serial converter 350 may be implemented by known techniques. The transmission driver 360 is used for outputting a transmission signal according to the serial data in the transmission mode. In a non-limiting exemplary embodiment, when the serializer/deserializer physical layer circuit 300 operates in the receiving mode, at least one of the pfd 410, the deserializer 350 and the transmit driver 360 is disabled according to the control signal to save power consumption; when the serializer/deserializer physical layer circuit 300 operates in the transmit mode, at least one of the sampling circuit 320 and the phase detector 330 is disabled according to the control signal to save power consumption.

The sampling circuit 320 of fig. 3 may receive the received signal through a conventional input circuit; in addition, the transmission driver 360 of fig. 3 can transmit the transmission signal through a conventional output circuit. To further save circuit area and pin (pin), for example, to meet the requirement of USB Type C interface, the serializer/deserializer physical layer circuit 300 of fig. 3 may further include an input/output (I/O) circuit coupled to the sampling circuit 320 and the transmit driver 360, such that the sampling circuit 320 and the transmit driver 360 share the I/O circuit for receiving and transmitting, respectively. In one embodiment of the I/O circuit shown in fig. 6, the I/O circuit 600 of fig. 6 includes a positive-end I/O pad 610, a negative-end I/O pad 620, a positive-end termination impedance (ZP) 630, a negative-end termination impedance (ZN) 640, a positive-end switch 650 (e.g., a transistor), and a negative-end switch 660 (e.g., a transistor). The positive terminal termination impedance 630 is coupled between the positive terminal I/O pad 610 and the negative terminal termination impedance 640. The negative terminal termination impedance 640 is coupled between the positive terminal termination impedance 630 and the negative terminal I/O pad 620. The positive terminal switch 650 includes a first terminal coupled to the positive terminal I/O pad 610 and the positive terminal impedance 630, and a second terminal coupled to the sampling circuit 320. The negative side switch 660 comprises a third terminal coupled to the negative side I/O pad 620 and the negative side termination impedance 640, and a fourth terminal coupled to the sampling circuit 320. The positive switch 650 and the negative switch 660 are turned on in the receiving mode (turned on) so that the sampling circuit 320 receives the receiving signal; at this time, the transfer driver 360 is disabled (disable). The positive side switch 650 and the negative side switch 660 are turned off in the transmission mode; at this time, the transmission driver 360 is enabled to transmit the transmission signal.

Fig. 7 shows an example of the positive terminal termination impedance 630 and the negative terminal termination impedance 640. As shown in fig. 7, the positive terminal impedance 630 includes a positive inductor 710 and a positive resistor 720, the negative terminal impedance 640 includes a negative inductor 730 and a negative resistor 740, the impedance of the positive terminal impedance 630 may be equal to or not equal to the impedance of the negative terminal impedance 640, and when the two impedances are equal, the voltage between the positive terminal impedance 630 and the negative terminal impedance 640 is the common mode voltage V_CM. In addition, the bandwidth corresponding to the received signal and the bandwidth corresponding to the transmitted signal can be increased by using the positive side inductor 710 and the negative side inductor 730.

FIG. 8 shows one embodiment of a pass driver 360 coupled to the I/O circuit 600 of FIG. 6. Referring to fig. 6 and 8, the transmission driver 360 includes: a first positive current source 810 coupled to a high voltage VDD; a first positive terminal transistor 820 coupled to the first positive current source 810 and the positive I/O pad 610; a second positive current source 830 coupled to a low voltage GND; a second positive terminal transistor 840 is coupled to the second positive terminal current source 830 and the positive terminal I/O pad 610; a first negative current source 850 coupled to the high voltage VDD; a first negative side transistor 860 coupled to the first negative side current source 850 and the negative side I/O pad 620; a second negative current source 870 coupled to the low voltage GND; and a second negative side transistor 880 coupled between the second negative side current source 870 and the negative side I/O pad 620, wherein each transistor is turned off (turned off) to disable the transmit driver 360 in the receive mode and turned on (turned on) to enable the transmit driver 360 in the transmit mode. In a non-limiting exemplary embodiment, the first positive current source 810, the second positive current source 830, the first negative current source 850, and the second negative current source 870 are turned off in the receive mode and turned on in the transmit mode.

It should be noted that, when the implementation is possible, a person skilled in the art may selectively implement some or all of the technical features of any one of the foregoing embodiments, or selectively implement a combination of some or all of the technical features of the foregoing embodiments, thereby increasing the flexibility in implementing the invention.

In summary, the serializer/deserializer physical layer circuit of the present invention integrates the receiving circuit and the transmitting circuit by way of a common circuit, thereby avoiding circuit area waste and achieving circuit miniaturization and high cost benefits.

Although the embodiments of the present invention have been described above, the embodiments are not intended to limit the present invention, and those skilled in the art can apply changes to the technical features of the present invention according to the explicit or implicit contents of the present invention, and all the changes may fall into the scope of the patent protection sought by the present invention.