Self-calibratable oscillating device and method and ASIC thereof

• US 20050122182A1
• Filed: 12/05/2003
• Published: 06/09/2005
• Est. Priority Date: 12/05/2003
• Status: Active Grant

• Current Assignee: Elite Semiconductor Memory Technology Inc.
• Original Assignee: Elite Semiconductor Memory Technology Inc.
• Inventors: Yao, Chung Ting
• Granted Patent: US 7,030,706 B2
• Time in Patent Office: Days
• US Class Current: 331/158
• CPC Class Codes: H03L 1/025 and a memory for digitally storing correction values
• CPC Class Codes: H03L 1/026 by using a memory for digitally storing correction values H03L1/025 takes precedence

Abstract

The present self-calibratable oscillating device includes a phase comparator, a clock pad electrically connected to a first input port of the phase comparator, a crystal oscillator electrically connected to a second input port of the phase comparator, an analog/digital converter electrically connected to an output port of the phase comparator, and a memory electrically connected to an output port of the analog/digital converter. The crystal oscillator can be a temperature-compensated crystal oscillator or a surface acoustic wave crystal oscillator. The present self-calibratable oscillating device can further includes a first switch positioned between the first input port of the phase comparator and the clock pad, a second switch positioned between the crystal oscillator and the clock pad wherein the stream direction of the first switch is in reverse of that of the second switch, and a logic control device for controlling the first switch and the second switch.

Claims

1. A self-calibratable oscillating device, comprising:

a phase comparator being comprised of a first input port, a second input port and an output port;

a clock pad electrically connected to the first input port;

a crystal oscillator electrically connected to the second input port;

an analog/digital converter electrically connected to the output port of the phase comparator; and

a memory electrically connected to an output end of the analog/digital converter.

2. The self-calibratable oscillating device of claim 1, wherein the crystal oscillator is comprised of a temperature-compensated crystal oscillator or a surface acoustic wave crystal oscillator.

3. The self-calibratable oscillating device of claim 1, further comprising:

a first switch positioned between the first input port of the phase comparator and the clock pad;

a second switch positioned between the crystal oscillator and the clock pad, wherein the stream direction of the second switch is in reverse of that of the first switch; and

a logic control device for controlling the first switch and the second switch.

4. The self-calibratable oscillating device of claim 3, further comprising:

a power pad; and

a high voltage detector electrically connected to the power pad and the logic control device.

5. The self-calibratable oscillating device of claim 3, further comprising an embedded clock generator to provide an operation clock for the logic control device.

6. The self-calibratable oscillating device of claim 5, wherein the embedded clock generator is comprised of a resistance-capacitor oscillator.

7. An ASIC for a crystal oscillator, comprising:

a system bus;

an embedded CPU electrically connected to the system bus;

a system memory electrically connected to the system bus;

a clock pad for receiving a reference clock;

a phase comparator for generating a phase difference signal between the reference clock and the clock of an oscillating device of the crystal oscillator; and

an analog/digital converter for converting the phase difference signal into a digital signal.

8. The ASIC for a crystal oscillator of claim 7, further comprising:

a first switch positioned between the phase comparator and the clock pad; and

a second switch positioned between the oscillating device and the clock pad.

9. The ASIC for a crystal oscillator of claim 8, further comprising a register electrically connected to the system bus for storing data of the system memory when the second switch is turn on.

10. A method for calibrating oscillating devices, comprising the steps of:

connecting a plurality of oscillating devices in parallel;

inputting an activation signal and a reference clock from a testing machine to the oscillating devices;

comparing the reference clock with the clock of an internal crystal oscillator inside each oscillating device to generate a phase difference signal; and

writing the phase difference signal into an internal memory in each oscillating device.

11. The method for calibrating oscillating devices of claim 10, wherein the activation signal keeps a voltage higher than a threshold voltage.

12. The method for calibrating oscillating devices of claim 10, further comprising a step of checking if an environmental temperature is equal to a final calibrating temperature.

13. The method for calibrating oscillating devices of claim 10, further comprising a step of converting the phase difference signal into a digital signal.