Phase locked loop

• US 9,257,998 B2
• Filed: 10/10/2013
• Issued: 02/09/2016
• Est. Priority Date: 10/10/2013
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Tsai, Tsung-Hsien
• Primary Examiner(s): O NEILL, PATRICK
• Application Number:
  US14/050,691
• Publication Number:
  US 20150102845A1
• Time in Patent Office: 852 Days
• US Class Current: 1/1
• CPC Class Codes: H03L 2207/50 All digital phase-locked loop
• CPC Class Codes: H03L 7/093 using special filtering or amplification characteristics in the loop H03L7/087 - H03L7/091 take precedence

Abstract

A circuit includes a phase locked loop and a logic IC. The phase locked loop is coupled to the logic IC. The logic IC is configured for generating an adaptive residue according to a first parameter and a second parameter. The phase locked loop is configured for providing the first parameter and the second parameter, and the phase locked loop generates an oscillator signal based on the adaptive residue.

Claims

1. A circuit, comprising:

a phase locked loop comprising a phase detector, a digital filter, and a digital control oscillator, the phase locked loop configured for providing a first parameter being related to a period of the phase detector and a period of the digital control oscillator and a second parameter being related to a frequency of the digital control oscillator and a frequency of a reference signal, the phase locked loop generating an oscillator signal based on an adaptive residue; and

a logic integrated circuit (IC) coupled to the phase locked loop and configured for using the first parameter, a bit number utilized by the phase locked loop, the second parameter, and a residue generated from an inverter of the phase detector, to generate the adaptive residue.

2. The circuit according to claim 1, wherein

the digital filter is coupled to the phase detector, and

the digital control oscillator is coupled to the digital filter.

3. The circuit according to claim 2, wherein the first parameter and the second parameter are determined as follows:

4. The circuit according to claim 3, wherein the logic IC comprises:

a first multiplier coupled to the phase detector, the first multiplier configured for multiplying the first parameter and the bit number utilized by the phase locked loop to generate a first calculated value;

a calculation logic gate coupled to the digital control oscillator, the calculation logic gate configured for using the second parameter and a third parameter generated according to the digital filter to generate a second calculated value;

an adder coupled to the calculation logic gate, the adder configured for adding the second calculated value and the residue generated from the inverter of the phase detector to generate a third calculated value; and

a second multiplier coupled to the first multiplier and the adder, the second multiplier configured for multiplying the first calculated value and the third calculated value to generate the adaptive residue.

5. The circuit according to claim 4, wherein the adaptive residue is determined as follows:

6. A circuit, comprising:

a digital control oscillator configured for generating a first oscillator signal based on an initial residue signal;

a phase detector coupled to the digital control oscillator, the phase detector configured for comparing the first oscillator signal with a reference signal to generate the initial residue signal; and

a digital filter coupled to the phase detector, the digital filter configured for modifying the initial residue signal based on an adaptive residue related to a first parameter, a second parameter, a bit number and a residue, to generate a modified residue signal, wherein the first parameter is related to a period of the phase detector and a period of the digital control oscillator, the bit number is utilized by a phase locked loop comprising the digital control oscillator, the phase detector and the digital filter, the second parameter is related to a frequency of the digital control oscillator and a frequency of a reference signal, and the residue is generated from an inverter of the phase detector, wherein the digital control oscillator is configured for generating a second oscillator signal base on the modified residue signal.

7. The circuit according to claim 6, wherein the first parameter is determined as follows:

8. The circuit according to claim 6, wherein the second parameter is determined as follows:

9. The circuit according to claim 6, further comprising:

a digital processor coupled to the phase detector and the digital control oscillator, the digital processor configured for gathering information from the digital control oscillator and the phase detector to generate the first parameter and the second parameter.

10. The circuit according to claim 9, further comprising:

a logic IC coupled to the digital filter and the digital processor, the logic IC configured for using the first parameter and the second parameter to generate the adaptive residue.

11. The circuit according to claim 10, wherein the logic IC comprises:

a first multiplier coupled to the digital processor, the first multiplier configured for multiplying the first parameter and the bit number utilized by the phase locked loop to generate a first calculated value;

a calculation logic gate coupled to the digital processor, the calculation logic gate configured for using the second parameter and a third parameter generated according to the digital filter to generate a second calculated value;

an adder coupled to the calculation logic gate, the adder configured for adding the second calculated value and the residue generated from the inverter of the phase detector to generate a third calculated value; and

a second multiplier coupled to the first multiplier and the adder, the second multiplier configured for multiplying the first calculated value and the third calculated value to generate the adaptive residue.

12. The circuit according to claim 6, wherein the adaptive residue is determined as follows:

13. A method, comprising:

generating a first oscillator signal based on an initial residue signal;

comparing the first oscillator signal with a reference signal to generate the initial residue signal;

modifying the initial residue signal based on an adaptive residue related to a first parameter, a second parameter, a bit number and a residue, to generate a modified residue signal, wherein the first parameter is related to a period of a phase detector and a period of a digital control oscillator, the bit number is utilized by a phase locked loop comprising the digital control oscillator and the phase detector, the second parameter is related to a frequency of the digital control oscillator and a frequency of a reference signal, and the residue is generated from an inverter of the phase detector; and

generating a second oscillator signal base on the modified residue signal.

14. The method according to claim 13, further comprising:

generating the first parameter based on the period of the phase detector and the period of the digital control oscillator.

15. The method according to claim 13, further comprising:

generating the second parameter based on the frequency of the digital control oscillator and the frequency of the reference signal.

16. The method according to claim 13, further comprising:

generating the adaptive residue based on the first parameter and the second parameter.

17. The method according to claim 16, wherein the step of generating the adaptive residue based on the first parameter and the second parameter comprises:

multiplying the first parameter and the bit number utilized by the phase locked loop to generate a first calculated value;

generating a second calculated value based on the second parameter and a third parameter generated according to a digital filter;

adding the second calculated value and the residue generated from the inverter of the phase detector to generate a third calculated value; and

multiplying the first calculated value and the third calculated value to generate the adaptive residue.