Circuit for and method of implementing a time-interleaved analog-to-digital converter

• US 9,503,115 B1
• Filed: 02/19/2016
• Issued: 11/22/2016
• Est. Priority Date: 02/19/2016
• Status: Active Grant

• Current Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Original Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Inventors: Shin, Jaewook, Hedayati, Hiva
• Primary Examiner(s): Mai, Lam T
• Application Number:
  US15/048,720
• Time in Patent Office: 277 Days
• Field of Search: 341140-166
• US Class Current: 1/1
• CPC Class Codes: G06F 1/10 Distribution of clock signals , e.g. skew
• CPC Class Codes: H03M 1/0836 of phase error, e.g. jitter
• CPC Class Codes: H03M 1/1215 using time-division multiplexing

Abstract

A circuit for implementing a time-interleaved analog-to-digital converter is described. The circuit comprises a sampling clock generator configured to receive a reference clock signal having a first frequency. The sampling clock generator has a first stage sampling clock generator configured to generate a first plurality of clock signals based upon the reference clock signal and having a second frequency, and a second stage sampling clock generator configured to generate, for each clock signal of the first plurality of clock signals, a second plurality of clock signals having a third frequency; a first stage having a plurality of switches configured to receive an analog input signal, wherein each switch of the plurality of switches is controlled by a corresponding clock signal of the first plurality of clock signals; and a second stage having a plurality of analog-to-digital converter banks, each analog-to-digital converter bank having a plurality of analog-to-digital converters and configured to receive the analog input signal by way of a corresponding switch of the plurality of switches.

Claims

1. A circuit for implementing a time-interleaved analog-to-digital converter circuit, the circuit comprising:

a sampling clock generator configured to receive a reference clock signal having a first frequency, the sampling clock generator having a first stage sampling clock generator configured to generate a first plurality of clock signals based upon the reference clock signal and having a second frequency, and a second stage sampling clock generator configured to generate, for each clock signal of the first plurality of clock signals, a second plurality of clock signals having a third frequency;

a first stage having a plurality of switches configured to receive an analog input signal, wherein each switch of the plurality of switches is controlled by a corresponding clock signal of the first plurality of clock signals; and

a second stage having a plurality of analog-to-digital converter banks, each analog-to-digital converter bank having a plurality of analog-to-digital converters and configured to receive the analog input signal by way of a corresponding switch of the plurality of switches; and

wherein each analog-to-digital converter bank of the plurality of analog-to-digital converter banks is configured to receive a plurality of clock phases of a corresponding clock signal of the second plurality of clock signals.

2. The circuit of claim 1 wherein the first stage sampling clock generator comprises a multi-phase clock generator generating divided clock signals at different phases and having the second frequency.

3. The circuit of claim 2 wherein the first stage sampling clock generator further comprises a sampling clock generator configured to receive the divided clock signals and to adjust a duty cycle and a delay of the divided clock signals to generate the first plurality of clock signals.

4. The circuit of claim 1 wherein the second stage sampling clock generator comprises a plurality of phase sampling clock generators, and each phase sampling clock generator is configured to receive a clock signal of the first plurality of clock signals and generate divided clock signals at different phases and having the third frequency.

5. The circuit of claim 4 wherein the sampling clock generator further comprises a synchronization circuit configured to receive a clock signal of the first plurality of clock signals and to generate a synchronization signal in response to a reset signal.

6. The circuit of claim 5 wherein each phase sampling clock generator of the plurality of phase sampling clock generators comprises a reset circuit, and wherein, for each phase sampling clock generator, the reset circuit aligns the synchronization signal to a clock signal coupled to the phase sampling clock generator.

7. The circuit of claim 1 further comprising a first buffer and a second buffer each configured to receive the analog input signal, wherein a first portion of switches of the plurality of switches is configured to receive the analog input signal by way of the first buffer and a second portion of switches of the plurality of switches is configured to receive the analog input signal by way of the second buffer.

8. The circuit of claim 1 further comprising an intermediate stage between the first stage and the second stage, the intermediate stage having a second plurality of switches configured to receive the analog input signal, wherein each switch of the second plurality of switches is controlled by a corresponding clock signal of a third plurality of clock signals.

9. The circuit of claim 8 wherein the sampling clock generator further comprises an intermediate stage sampling clock generator having a clock generator configured to generate divided clock signals at different phases and based upon the first plurality of clock signals.

10. The circuit of claim 9 wherein the sampling clock generator further comprises a synchronization circuit configured to receive a clock signal of the first plurality of clock signals and to generate synchronization signals coupled to the intermediate stage and the second stage in response to a reset signal.

11. A method of implementing a time-interleaved analog-to-digital converter, the method comprising:

configuring a sampling clock generator to receive a reference clock signal having a first frequency;

generating, by the sampling clock generator, a first plurality of clock signals based upon the reference clock signal and having a second frequency;

generating, for each clock signal of the first plurality of clock signals, a second plurality of clock signals having a third frequency;

receiving an analog input signal at a plurality of switches, wherein each switch of the plurality of switches is controlled by a corresponding clock signal of the first plurality of clock signals; and

implementing a plurality of analog-to-digital converter banks, each analog-to-digital converter bank having a plurality of analog-to-digital converters and configured to receive the analog input signal by way of a corresponding switch of the plurality of switches;

wherein each analog-to-digital converter bank of the plurality of analog-to-digital converter banks is configured to receive a plurality of clock phases of a corresponding clock signal of the second plurality of clock signals.

12. The method of claim 11 wherein generating the first plurality of clocks signals comprises generating, based on the reference clock signal, divided clock signals at different phases and having the second frequency.

13. The method of claim 12 wherein generating the first plurality of clocks signals comprises adjusting a duty cycle and a delay of the divided clock signals.

14. The method of claim 11 further comprising implementing a plurality of phase sampling clock generators, wherein each phase sampling clock generator is configured to receive a clock signal of the first plurality of clock signals and generate divided clock signals at different phases and having the third frequency.

15. The method of claim 14 further comprising configuring a synchronization circuit to receive a clock signal of the first plurality of clock signals and to generate a synchronization signal in response to a reset signal.

16. The method of claim 15 further comprising implementing, for each phase sampling clock generator of the plurality of phase sampling clock generators, a reset circuit, and wherein, for each phase sampling clock generator, the reset circuit aligns the synchronization signal to a clock signal coupled to the phase sampling clock generator.

17. The method of claim 11 further comprising configuring a first buffer and a second buffer to receive the analog input signal, wherein a first portion of switches of the plurality of switches is configured to receive the analog input signal by way of the first buffer and a second portion of switches of the plurality of switches is configured to receive the analog input signal by way of the second buffer.

18. The method of claim 11 further comprising implementing an intermediate stage between the first stage and the second stage, the intermediate stage having a second plurality of switches configured to receive the analog input signal, wherein each switch of the second plurality of switches is controlled by a corresponding clock signal of a third plurality of clock signals.

19. The method of claim 18 wherein the implementing the intermediate stage comprises generating divided clock signals at different phases and based upon the first plurality of clock signals.

20. The method of claim 19 further comprising implementing a synchronization circuit to receive a clock signal of the first plurality of clock signals and to generate synchronization signals coupled to the intermediate stage and the second stage in response to a reset signal.