High-speed wide bandwidth data detection circuit

• US 7,224,760 B1
• Filed: 04/22/2003
• Issued: 05/29/2007
• Est. Priority Date: 01/17/2003
• Status: Active Grant

• Current Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Original Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Inventors: Rokhsaz, Shahriar, Brunn, Brian T., Younis, Ahmed, Robinson, Moises E.
• Primary Examiner(s): Payne; David C.
• Assistant Examiner(s): File; Erin M.
• Application Number:
  US10/421,512
• Time in Patent Office: 1,498 Days
• Field of Search: 375/375, 375/327, 375/376, 360/46, 360/51, 360/53, 370/335, 370/342, 714/755
• US Class Current: 375/376
• CPC Class Codes: H03D 13/003 in which both oscillations are converted by logic means into pulses which are applied to filtering or integrating means
• CPC Class Codes: H03L 7/087 using at least two phase detectors or a frequency and phase detector in the loop
• CPC Class Codes: H03L 7/0896 the current generators being controlled by differential up-down pulses
• CPC Class Codes: H03L 7/091 the phase or frequency detector using a sampling device H03L7/087 takes precedence
• CPC Class Codes: H03L 7/113 using frequency discriminator
• CPC Class Codes: H04L 7/0331 with a digital phase-locked loop [PLL] processing binary samples, e.g. add/subtract logic for correction of receiver clock H04L7/0337 takes precedence

Abstract

A high-speed, wide bandwidth data detection circuit includes a phase detection module, a data detection module, a loop filter, and a voltage controlled oscillator. The phase detection module is operably coupled to produce a controlled current based on a current mode mathematical manipulation of differences between an incoming data stream and a recovered clock. The phase detection module performs the current mode mathematical manipulations and produces the controlled current in the current domain. The data detection module is operably coupled to produce the detected data based on the incoming data stream and the recovered clock. The loop filter is operably coupled to convert the controlled current into a controlled voltage. The voltage controlled oscillator is operably coupled to convert the control voltage into the recovered clock.

Claims

1. A high-speed, wide bandwidth data detection circuit comprises:

phase detection module operably coupled to produce controlled current based on a current mode mathematical manipulation of differences between an incoming data stream and a recovered clock;

data detection module operably coupled to produce the detected data based on the incoming data stream and the recovered clock;

loop filter operably coupled to convert the controlled current into a control voltage;

voltage controlled oscillator operably coupled to convert the control voltage into the recovered clock; and

wherein the phase detection module comprises;

a first differential exclusive OR gate operably coupled to produce a first differential current component of the controlled current based on a first representation of the incoming data stream and a second representation of the incoming data stream;

a second differential exclusive OR gate operably coupled to produce a second differential current component of the controlled current based on a third representation of the incoming data stream and a fourth representation of the incoming data stream;

a first current source module operably coupled to provide a first reference current;

a second current source module operably coupled to provide a second reference current; and

a differential common gate amplifier circuit operably coupled to the first and second differential exclusive OR gates and to the first and second current source modules, wherein the differential common gate amplifier circuit produces a differential controlled current based on the first and second differential current components and the first and second reference currents.

2. The high-speed, wide bandwidth data detection circuit of claim 1 further comprises:

a first latch operably coupled to produce the first representation of the incoming data stream based on the incoming data stream and the recovered clock;

a second latch operably coupled to produce the second representation of the incoming data stream based on the incoming data stream and an inverse of the recovered clock;

a first flip-flop operably coupled to produce the third representation of the incoming data stream based on the first representation of the incoming data stream and the inverse of the recovered clock; and

a second flip-flop operably coupled to produce the fourth representation of the incoming data stream based on the second representation of the incoming data stream and the recovered clock.

3. The high-speed, wide bandwidth data detection circuit of claim 1 further comprises:

the first current source module including a first reference current source and a second reference current source, wherein the first reference current source provides a current having a magnitude approximately twice a magnitude of the first differential current component, and wherein the second reference current source provides a current having a magnitude approximately N times the magnitude of the first differential current component, wherein the currents produced by the first and second reference current sources are provided as the first reference current to one differential input of the differential common gate amplifier circuit; and

the second current source module including a third reference current source and a fourth reference current source, wherein the third reference current source provides a current having a magnitude approximately twice a magnitude of the second differential current component, and wherein the fourth reference current source provides a current having a magnitude approximately N times the magnitude of the first differential current component, wherein the currents produced by the third and fourth reference current sources are provided as the second reference current to another differential input of the differential common gate amplifier circuit.

4. The high-speed, wide bandwidth data detection circuit of claim 1, wherein the phase detection module further comprises:

a common mode feedback circuit operably coupled to the differential common gate amplifier circuit.

5. A method for high-speed wide bandwidth data detection, the method comprises:

producing a controlled current based on a current mode mathematical manipulation of differences between an incoming data stream and a recovered clock;

producing detected data based on the incoming data stream and the recovered clock;

converting the controlled current into a control voltage;

converting the control voltage into the recovered clock; and

wherein producing the controlled current includes,

exclusive ORing a first representation of the incoming data stream and a second representation of the incoming data stream to produce a first differential current component of the controlled current;

exclusive ORing a third representation of the incoming data stream and a fourth representation of the incoming data stream to produce a second differential current component of the controlled current;

generating a first reference current;

generating a second reference current; and

producing a differential controlled current based on the first and second differential current components and the first and second reference currents.

6. The method of claim 5 further comprises:

generating the first reference current by;

producing a first current having a magnitude approximately twice a magnitude of the first differential current component;

producing a second current having a magnitude approximately N times the magnitude of the first differential current component;

combining the first and second currents to produce the first reference current; and

generating the second reference current by;

producing a third current having a magnitude approximately twice a magnitude of the second differential current component;

producing a fourth current having a magnitude approximately N times the magnitude of the first differential current component; and

combining the third and fourth currents to produce the second reference current.

7. An apparatus for high-speed wide bandwidth data detection, the apparatus comprises:

processing module;

memory operably coupled to the processing module, wherein the memory includes operational instructions that cause the processing module to;

produce a controlled current based on a current mode mathematical manipulation of differences between the incoming data stream and a recovered clock;

produce detected data based on the incoming data stream and the recovered clock;

convert the controlled current into a control voltage; and

convert the control voltage into the recovered clock; and

wherein the memory further comprises operational instructions that cause the processing module to generate the controlled current by;

exclusive ORing a first representation of the incoming data stream and a second representation of the incoming data stream to produce a first differential current component of the controlled current;

exclusive ORing a third representation of the incoming data stream and a fourth representation of the incoming data stream to produce a second differential current component of the controlled current;

generating a first reference current;

generating a second reference current; and

producing a differential controlled current based on the first and second differential current components and the first and second reference currents.

8. The apparatus of claim 7, wherein the memory further comprises operational instructions that cause the processing module to:

generate the first reference current by;

producing a first current having a magnitude approximately twice a magnitude of the first differential current component;

producing a second current having a magnitude approximately N times the magnitude of the first differential current component;

combining the first and second currents to produce the first reference current; and

generate the second reference current by;

producing a third current having a magnitude approximately twice a magnitude of the second differential current component;

producing a fourth current having a magnitude approximately N times the magnitude of the first differential current component; and

combining the third and fourth currents to produce the second reference current.

9. A high-speed, wide bandwidth data detection circuit comprises:

primary locked loop operably coupled to process an incoming data stream to produce detected data and a recovered clock, wherein the primary locked loop includes;

phase detection module operably coupled to produce controlled current based on a current mode mathematical manipulation of differences between the incoming data stream and the recovered clock, wherein, when the primary locked loop is in an idle state, the phase detection module produces a substantially zero controlled current, and when the primary locked loop transitions from the idle state to an active state, the phase detection module produces the controlled current in a known manner;

data detection module operably coupled to produce the detected data based on the incoming data stream and the recovered clock;

loop filter operably coupled to convert the controlled current into a control voltage;

voltage controlled oscillator operably coupled to convert the control voltage into the recovered clock;

secondary locked loop operably coupled to provide an initial coarse locking for the primary locked loop when the primary locked loop is in the idle state; and

state transition module operably coupled to place the primary locked loop in the idle state and the secondary locked loop in the active state and to switch the primary locked loop from the idle state to the active state and to switch the second locked loop from the active state to the idle state during non-updating periods of the phase detection module.

10. The high-speed, wide bandwidth data detection circuit of claim 9, wherein the phase detection module further comprises:

phase detection circuit operably coupled to produce phase information based on the phase difference between the incoming data stream and the recovered clock; and

a charge pump circuit operably coupled to produce the controlled current based on the phase information, wherein, when the primary locked loop is in the idle state, the phase detection circuit generates the phase information such that the charge pump circuit produces the substantially zero controlled current.

11. The high-speed, wide bandwidth data detection circuit of claim 10, wherein the phase detection circuit further comprises:

a first exclusive OR gate operably coupled to produce a phase signal of the phase information based on first representation of the incoming data stream and a second representation of the incoming data stream;

a second exclusive OR gate operably coupled to produce a transition signal of the phase information based on a third representation of the incoming data stream and a fourth representation of the incoming data stream;

a first latch operably coupled to produce the first representation of the incoming data stream based on the incoming data stream and the recovered clock;

a second latch operably coupled to produce the second representation of the incoming data stream based on the incoming data stream and an inverse of the recovered clock;

a first flip-flop operably coupled to produce the third representation of the incoming data stream based on the first representation of the incoming data stream and the inverse of the recovered clock;

a second flip-flop operably coupled to produce the fourth representation of the incoming data stream based on the second representation of the incoming data stream and the recovered clock; and

control module operably coupled to control at least one of the phase signal and the transition signal when the primary locked loop is in the idle state.

12. The high-speed, wide bandwidth data detection circuit of claim 11, wherein the control module further function to control the phase signal or the transition signal by at least one of:

forcing an output of the first exclusive OR gate to a known state;

forcing an output of the second exclusive OR gate to a known state;

forcing inputs of the first exclusive OR gate to a same known state;

forcing inputs of the second exclusive OR gate to a same known state;

forcing inputs of the first and second latches to a known state; and

forcing inputs of the first and second flip-flops to a known state.

13. A method for high-speed, wide bandwidth data detection, the method comprises:

generating an initial coarse locking based on a reference signal and a feedback signal during an idle mode of operation;

generating a substantially zero controlled current during the idle mode of operation;

when the initial coarse locking is achieved, switching from the idle mode of operation to an active mode of operation;

when in the active mode of operation;

producing a controlled current based on a current mode mathematical manipulation of differences between an incoming data stream and a recovered clock, wherein transition from the substantially zero controlled current to the controlled current is done in a known manner;

producing detected data based on the incoming data stream and the recovered clock;

converting the controlled current into a control voltage;

converting the control voltage into the recovered clock; and

wherein the memory further comprises operational instructions that cause the processing module to;

transitioning from the idle mode of operation to the active mode of operation during non-updating periods of the generating of the controlled current and of the generating of the substantially zero controlled current.

14. The method of claim 13, wherein the producing the controlled current further comprises:

producing phase information based on the differences between the incoming data stream and the recovered clock; and

producing the controlled current based on the phase information, wherein, when in the idle mode of operation, the phase information is such that the controlled current is the substantially zero controlled current.

15. The method of claim 14, wherein the producing the phase information further comprises:

exclusive ORing a first representation of the incoming data stream and a second representation of the incoming data stream to produce a phase signal of the phase information;

exclusive ORing a third representation of the incoming data stream and a fourth representation of the incoming data stream to produce a transition signal of the phase information;

producing the first representation of the incoming data stream based on the incoming data stream and the recovered clock;

producing the second representation of the incoming data stream based on the incoming data stream and an inverse of the recovered clock;

producing the third representation of the incoming data stream based on the first representation of the incoming data stream and the inverse of the recovered clock;

producing the fourth representation of the incoming data stream based on the second representation of the incoming data stream and the recovered clock; and

controlling at least one of the phase signal and the transition signal when in the idle mode of operation.

16. The method of claim 15, wherein the controlling of the phase signal or the transition signal further comprises at least one of:

forcing a result of the exclusive ORing of the first and second representations of the incoming data stream to a known state;

forcing a result of the exclusive ORing of the third and fourth representations of the incoming data stream to a known state;

forcing the first and second representations of the incoming data stream to a same known state; and

forcing the third and fourth representations of the incoming data stream to a same known state.

17. An apparatus for high-speed, wide bandwidth data detection, the apparatus comprises:

processing module;

memory operably coupled to the processing module, wherein the memory includes operational instructions that cause the processing module to;

generate an initial coarse locking based on a reference signal and a feedback signal during an idle mode of operation;

generate a substantially zero controlled current during the idle mode of operation;

when the initial coarse locking is achieved, switch from the idle mode of operation to an active mode of operation;

when in the active mode of operation;

produce a controlled current based on a current mode mathematical manipulation of differences between an incoming data stream and a recovered clock, wherein transition from the substantially zero controlled current to the controlled current is done in a known manner;

produce detected data based on the incoming data stream and the recovered clock;

convert the controlled current into a control voltage;

convert the control voltage into the recovered clock;

wherein the memory further comprises operational instructions that cause the processing module to;

transition from the idle mode of operation to the active mode of operation during non-updating periods of the generating of the controlled current and of the generating of the substantially zero controlled current.

18. The apparatus of claim 17, wherein the memory further comprises operational instructions that cause the processing module to produce the controlled current by:

producing phase information based on the phase difference between the incoming data stream and the recovered clock; and

producing the controlled current based on the phase information, wherein, when in the idle mode of operation, the phase information is such that the controlled current is the substantially zero controlled current.

19. The apparatus of claim 18, wherein the memory further comprises operational instructions that cause the processing module to produce the phase information by:

exclusive ORing a first representation of the incoming data stream and a second representation of the incoming data stream to produce a phase signal of the phase information;

exclusive ORing a third representation of the incoming data stream and a fourth representation of the incoming data stream to produce a transition signal of the phase information;

producing the first representation of the incoming data stream based on the incoming data stream and the recovered clock;

producing the second representation of the incoming data stream based on the incoming data stream and an inverse of the recovered clock;

producing the third representation of the incoming data stream based on the first representation of the incoming data stream and the inverse of the recovered clock;

producing the fourth representation of the incoming data stream based on the second representation of the incoming data stream and the recovered clock; and

controlling at least one of the phase signal and the transition signal when in the idle mode of operation.

20. The apparatus of claim 19, wherein the memory further comprises operational instructions that cause the processing module to control the phase signal or the transition signal by at least one of:

forcing a result of the exclusive ORing of the first and second representations of the incoming data stream to a known state;

forcing a result of the exclusive ORing of the third and fourth representations of the incoming data stream to a known state;

forcing the first and second representations of the incoming data stream to a same known state; and

forcing the third and fourth representations of the incoming data stream to a same known state.

21. A high-speed, wide bandwidth data detection circuit comprises:

phase detection module operably coupled to produce primary controlled current based on a current mode mathematical manipulation of phase differences between the incoming data stream and a recovered clock when fine loop operation is enabled;

data detection module operably coupled to produce the detected data based on the incoming data stream and the recovered clock;

frequency detector operably coupled to produce a frequency difference signal based on frequency differences between a reference signal and a feedback signal when coarse loop operation is enabled;

charge pump operably coupled to convert the frequency difference signal into a secondary controlled current when the coarse loop operation is enabled;

loop filter operably coupled to convert the primary controlled current or the secondary controlled current into a control voltage;

common mode feedback circuit operably coupled to the loop filter to provide a common mode reference for the primary and secondary controlled currents;

voltage controlled oscillator operably coupled to convert the control voltage into the recovered clock when the fine loop operation is enabled and to convert the control voltage into an intermediate clock when the coarse loop operation is enabled; and

divider module operably coupled to produce the feedback signal based on the intermediate clock and a divider value.

22. The high-speed, wide bandwidth data detection circuit of claim 21, wherein the common mode feedback circuit further comprises:

a first current source operably coupled to one differential input of the loop filter and to a common mode reference voltage; and

a second current source operably coupled to another differential input of the loop filter and to the common mode reference voltage.

23. The high-speed, wide bandwidth data detection circuit of claim 21 further comprises:

the phase detection module including an output stage to provide the primary controlled current to the loop filter; and

the charge pump including an output stage to provide the secondary controlled current to the loop filter, wherein the output stage provides a zero net current for the secondary controlled current when the fine loop operation is enabled.

24. The high-speed, wide bandwidth data detection circuit of claim 23, wherein the output stages of the phase detection module and the charge pump each further comprises:

reference current source operably coupled to provide a reference current;

common gate amplifier operably coupled to the reference current source; and

common mode controlled current source operably coupled to the common gate amplifier, wherein a node coupling the reference current source to the common gate amplifier provides an input for the output stage and a node coupling the common gate amplifier to the common mode controlled current source provides an output of the output stage.

25. A phase detection module comprising:

first current mode logic circuit operably coupled to perform a first portion of a current mode mathematical manipulation on phase differences between an incoming data stream and a recovered clock to produce a first differential current component of a controlled current, the first current mode logic circuit including,

a first differential exclusive OR gate operably coupled to produce the first differential current component of the controlled current based on a first representation of the incoming data stream and a second representation of the incoming data stream; and

a first current source module operably coupled to provide a first reference current;

second current mode logic circuit operably coupled to perform a second portion of the current mode mathematical manipulation on transition differences between the incoming data stream and the recovered clock to produce a second differential current component of the controlled current, the second current mode logic circuit including,

a second differential exclusive OR gate operably coupled to produce the second differential current component of the controlled current based on a third representation of the incoming data stream and a fourth representation of the incoming data stream; and

a second current source module operably coupled to provide a second reference current; and

a differential common gate amplifier circuit operably coupled to the first and second differential exclusive OR gates and to the first and second current source modules, wherein the differential common gate amplifier circuit produces a differential controlled current based on the first and second differential current components and the first and second reference currents.