Timing generating apparatus with self-calibrating capability

• US 6,304,119 B1
• Filed: 12/27/2000
• Issued: 10/16/2001
• Est. Priority Date: 12/27/2000
• Status: Expired due to Fees

• Current Assignee: Chroma ATE Incorporated
• Original Assignee: Chroma ATE Incorporated
• Inventors: Lin, Chih-Hung, Tseng, I-Shih, Tseng, Huan-Ming, Yang, Chun-Min, Su, Chau-Chin
• Primary Examiner(s): TON, MY TRANG
• Application Number:
  US09/748,926
• Time in Patent Office: 293 Days
• Field of Search: 327/141, 327/142, 327/148, 327/149, 327/150, 327/151, 327/160, 327/161, 327/157-159, 327/202, 327/199, 327/261, 327/26
• US Class Current: 327/161
• CPC Class Codes: G01R 31/3191 Calibration
• CPC Class Codes: G01R 31/31922 Timing generation or clock distribution G01R31/3191 takes precedence
• CPC Class Codes: H03L 7/07 using several loops, e.g. for redundant clock signal generation
• CPC Class Codes: H03L 7/0805 the loop being adapted to provide an additional control signal for use outside the loop
• CPC Class Codes: H03L 7/0812 and where no voltage or current controlled oscillator is used

Abstract

A timing generating apparatus includes a master timing module adapted to receive an external reference clock and to generate a coarse timing pulse signal. A slave timing module is coupled electrically to the master timing module and receives the coarse timing pulse signal, from which a fine timing pulse signal is generated. A calibration module coupled electrically to the master timing module and the slave timing module receives the coarse timing pulse signal and the fine timing pulse signal, determines a phase difference value between the two, and generates a phase compensation signal corresponding to difference between the phase difference value and a predetermined phase difference value. The slave timing module includes a delay control unit and a voltage-controlled delay unit, which introduce a phase delay into the coarse timing pulse signal so as to generate the fine timing pulse signal.

Claims

1. A timing generating apparatus comprising:

a master timing module adapted to receive an external reference clock and to generate a coarse timing pulse signal therefrom;

a slave timing module coupled electrically to said master timing module so as to receive the coarse timing pulse signal therefrom, and operable so as to generate a fine timing pulse signal from the coarse timing pulse signal; and

a calibration module coupled electrically to said master timing module and said slave timing module, said calibration module receiving the coarse timing pulse signal and the fine timing pulse signal, determining a phase difference value between the coarse timing pulse signal and the fine timing pulse signal, and generating a phase compensation signal corresponding to difference between the phase difference value and a predetermined phase difference value;

said slave timing module including

a delay control unit that receives the phase compensation signal from said calibration module, and that generates a delay voltage signal corresponding to the phase compensation signal, and

a voltage-controlled delay unit that receives the coarse timing pulse signal and the delay voltage signal, and that introduces a phase delay corresponding to the delay voltage signal into the coarse timing pulse signal so as to generate the fine timing pulse signal.

2. The timing generating apparatus of claim 1, wherein said calibration module includes:

a phase detecting unit for generating a phase difference pulse when the coarse timing pulse signal and the fine timing pulse signal are at different logic states; and

a phase measuring unit coupled electrically to said phase detecting unit for generating the phase difference value that corresponds to width of the phase difference pulse.

3. The timing generating apparatus of claim 2, wherein said phase detecting unit includes an exclusive OR gate.

4. The timing generating apparatus of claim 2, wherein said phase measuring unit includes a digital counter.

5. The timing generating apparatus of claim 4, wherein said calibration module further includes a phase compensating unit having

a register for storing the predetermined phase difference value, and

a subtracter coupled electrically to said register and said phase measuring unit, said subtracter receiving the phase difference value from said phase measuring unit and the predetermined phase difference value from said register, and generating the phase compensation signal.

6. The timing generating apparatus of claim 1, wherein said delay control unit includes:

a charge-pumping circuit having an input that receives the phase compensation signal from said phase compensating unit, and an output; and

a capacitor connected across said output of said charge-pumping circuit, the delay voltage signal being obtained across said capacitor.

7. The timing generating apparatus of claim 1, wherein said voltage-controlled delay unit includes:

a voltage-controlled variable gain buffer that receives the delay voltage signal and the coarse timing pulse signal, and that has an output;

a capacitor connected across said output of said voltage-controlled variable gain buffer; and

a fixed gain output buffer that is coupled electrically to said output of said voltage-controlled variable gain buffer, and that has an output from which the fine timing pulse signal is obtained.