Digital-to-time converter, time-to-digital converter, and converting method using the same

• US 10,642,227 B1
• Filed: 03/15/2019
• Issued: 05/05/2020
• Est. Priority Date: 03/15/2019
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Lin, Yu-Tso
• Primary Examiner(s): Jeanglaude, Jean B
• Application Number:
  US16/354,176
• Time in Patent Office: 417 Days
• Field of Search: 341152
• CPC Class Codes: G04F 10/005 Time-to-digital converters [TDC] analog-to-digital converters with intermediate conversion to time or phase H03M1/50, H03M1/60
• CPC Class Codes: H03K 19/20 characterised by logic function, e.g. AND, OR, NOR, NOT circuits H03K19/003 - H03K19/01 take precedence
• CPC Class Codes: H03K 2005/00058 controlled by a digital setting
• CPC Class Codes: H03K 5/01 Shaping pulses discrimination against noise or interference H03K5/125

Abstract

A digital-to-time converter (DTC) includes a plurality of delay stages connected in series, in which each of the plurality of delay stages includes an input circuit and a delay circuit. The input circuit has a first input terminal, a second input terminal and a first output terminal, and is configured to receive a clock signal through the first input terminal, receive a digital control signal through the second input terminal, generate an output signal according to the clock signal and the digital control signal, and output the output signal to the first output terminal of the input circuit. The delay circuit is coupled to the input circuit in series, and is configured to receive the output signal and an input signal, and generate a delay signal according to the output signal and the input signal. The delay signal indicates a time interval corresponding to the digital control signal.

Claims

1. A digital-to-time converter, comprising:

a plurality of delay stages connected in series, wherein each of the plurality of delay stages comprises;

an input circuit, having a first input terminal, a second input terminal and a first output terminal, configured to receive a clock signal through the first input terminal, receive a digital control signal through the second input terminal, generate an output signal according to the clock signal and the digital control signal, and output the output signal to the first output terminal of the input circuit; and

a delay circuit, coupled to the input circuit in series, and configured to receive the output signal and an input signal, and generate a delay signal according to the output signal and the input signal, wherein the delay signal indicates a time interval corresponding to the digital control signal.

2. The digital-to-time converter of claim 1, wherein the delay circuit comprises:

a third input terminal, coupled to the first output terminal of the input circuit;

a fourth input terminal, configured to receive the input signal; and

a second output terminal, configured to output the delay signal.

3. The digital-to-time converter of claim 2, wherein the delay stages comprise a first delay stage and a second delay stage, the second delay stage is next to the first delay stage, and the delay signal of a first delay stage is the input signal of the second delay stage.

4. The digital-to-time converter of claim 2, wherein

the input circuit comprises a first logic gate, and the input circuit is configured to perform a first logic operation to the clock signal and the digital control signal using the first logic gate to generate the output signal, and

the delay circuit comprises a second logic gate, and the delay circuit is configured to perform a second logic operation to the output signal and the input signal to generate the delay signal.

5. The digital-to-time converter of claim 4, wherein the first logic gate is an OR gate, the first logic operation is an OR logic operation, the second logic gate is an AND gate, and the second logic operation is an AND logic operation.

6. The digital-to-time converter of claim 2, wherein each of the plurality of delay stages is activated or deactivated according to the digital control signal.

7. The digital-to-time converter of claim 6, wherein

a number of delay stages to be activated is adjusted according to the digital control signal,

the digital control signal is configured to block the clock signal to a delay stage among the plurality of the delay stages to deactivate the delay stage, and

the digital control signal is configured to allow the clock signal to a delay stage among the plurality of the delay stages to active the delay stage.

8. A converting method adapted to a digital-to-time converter having a plurality of delays stages, each of the plurality of delay stages having an input circuit and a delay circuit, the converting method comprising:

providing a clock signal to a first input terminal of the input circuit;

providing a digital control signal to a second input terminal of the input circuit;

performing a first logic operation to the clock signal and the digital control signal to generate an output signal;

providing an input signal and the output signal to the delay circuit;

performing a second logic operation to the input signal and the output signal to generate a delay signal, wherein the delay signal indicates a time interval corresponding to the digital control signal.

9. The converting method of claim 8, wherein the first logic operation is an OR logic operation and the second logic operation is an AND logic operation.

10. The converting method of claim 8, wherein the digital control signal is configured to activate or deactivate each of the plurality of delay stages.

11. The converting method of claim 10, wherein

a number of delay stages to be activated is adjusted according to the digital control signal,

the digital control signal is configured to block the clock signal to a delay stage among the plurality of delay stages to deactivate the delay stage;

and

the digital control signal is configured to allow the clock signal to a delay stage among the plurality of delay stages to active the delay stage.

12. A time-to-digital converter, comprising:

a plurality of stages connected in series, wherein each of the plurality of stages comprises;

a delay circuit, configured to receive a first clock signal and delay the first clock signal to generate a delay clock signal;

a sampling circuit, configured to receive a second clock signal, a digital control signal and the delay clock signal, and perform a sampling operation to sample the delay clock signal according to the second clock signal and the digital control signal to generate a digital output signal,

wherein a frequency of the first clock signal is greater than a frequency of the second clock signal, and the sampling circuit of each of the plurality of stages is activated or deactivated according to the digital control signal.

13. The time-to-digital converter of claim 12, wherein the sampling circuit comprises:

a logic gate, having a first input terminal and a second input terminal, wherein the first input terminal receives the second clock signal, the second input terminal receives the digital control signal, and the logic gate is configured to perform a logic operation to the second clock signal and the digital control signal to generate a third clock signal.

14. The time-to-digital converter of claim 13, wherein the sampling circuit further comprises:

a latch circuit, coupled to the delay circuit and the logic gate, configured to receive the delay clock signal from the delay circuit and the third clock signal from the logic gate, and sample the delay clock signal according to the third clock signal to generate the digital output signal.

15. The time-to-digital converter of claim 13, wherein the logic operation is configured to activate or deactivate each of the stages according to the digital control signal.

16. The time-to-digital converter of claim 15, wherein a number of stages to be activated is adjusted according to the digital control signal.

17. The time-to-digital converter of claim 15, wherein

the digital control signal is configured to block the second clock signal to a stage among the plurality of the stages to deactivate the stage, and

the digital control signal is configured to allow the second clock signal to a stage among the plurality of the stages to active the stage.

18. The time-to-digital converter of claim 14, wherein the logic gate is an AND gate, and the logic operation is an AND logic operation.

19. The time-to-digital converter of claim 12, wherein

the plurality of stages comprises a first stage and a second stage,

the second stage is next to the first stage, and

an output terminal of the delay circuit of the first stage is coupled to an input terminal of the delay circuit of the second stage.

20. The time-to-digital converter of claim 12, wherein the delay circuit includes at least one inverter.