METHOD FOR DETECTING MINIMUM OPERATIONAL FREQUENCY

• US 20100231265A1
• Filed: 05/21/2010
• Published: 09/16/2010
• Est. Priority Date: 04/18/2008
• Status: Active Grant

• Current Assignee: Nanya Technology Corporation
• Original Assignee: Nanya Technology Corporation
• Inventors: Dale, Bret Roberts, Jurasek, Ryan Andrew, Daudelin, Darin James, Chapmen, Dave Eugene
• Granted Patent: US 8,044,691 B2
• Time in Patent Office: Days
• US Class Current: 327/47
• CPC Class Codes: H03K 3/0315 Ring oscillators

Abstract

A method of detecting a minimum operational frequency includes: generating a signal that becomes an oscillating signal at a first predetermined frequency; and generating a logic signal to provide a level transition when a frequency of the oscillating signal reaches a second predetermined frequency corresponding to the minimum operational frequency. The logic signal is generated by: providing a transistor that is activated at the second predetermined frequency; providing a capacitor; storing charges in the capacitor when the oscillating signal is below the second predetermined frequency; discharging the capacitor when the transistor is activated by the oscillating signal; and outputting the logic signal when the capacitor discharges.

Claims

1. A method of detecting a minimum operational frequency, comprising:

generating a signal that becomes an oscillating signal at a first predetermined frequency; and

generating a logic signal to provide a level transition when a frequency of the oscillating signal reaches a second predetermined frequency corresponding to the minimum operational frequency.

2. The method of claim 1, wherein the step of generating the signal that becomes an oscillating signal at a first predetermined frequency comprises:

generating a first oscillating signal by increasing frequency of the generated signal; and

generating a second oscillating signal by filtering the first oscillating signal to reduce noise;

and the step of generating the logic signal comprises;

generating the logic signal when a frequency of the first oscillating signal reaches the second predetermined frequency.

3. The method of claim 2, wherein the second oscillating signal is generated at a third predetermined frequency and a predetermined amplitude of the first oscillating signal, and the logic signal is generated after the second oscillating signal is generated.

4. The method of claim 2, wherein the step of generating the logic signal when the first oscillating signal reaches the second predetermined frequency comprises:

providing a transistor that is activated when the first oscillating signal reaches the second predetermined frequency; and

generating the logic signal when the transistor is activated.

5. The method of claim 2, wherein the step of generating the logic signal when the first oscillating signal reaches the second predetermined frequency comprises:

providing a capacitor;

storing charges in the capacitor until the first oscillating signal reaches the second predetermined frequency and discharging the capacitor when the first oscillating signal reaches the second predetermined frequency; and

outputting the logic signal when the capacitor discharges.

6. The method of claim 1, wherein the step of generating a logic signal when the oscillating signal reaches a second predetermined frequency comprises:

providing a transistor that is activated at the second predetermined frequency;

providing a capacitor;

storing charges in the capacitor when the oscillating signal is below the second predetermined frequency;

discharging the capacitor when the transistor is activated by the oscillating signal; and

outputting the logic signal when the capacitor discharges.

7. The method of claim 6, wherein the step of generating the signal that becomes an oscillating signal at a first predetermined frequency comprises:

generating a first oscillating signal by increasing the frequency of the generated signal; and

generating a second oscillating signal by filtering the first oscillating signal to reduce noise.

8. The method of claim 7, wherein the second oscillating signal is generated at a third predetermined frequency and a predetermined amplitude of the first oscillating signal, and the logic signal is generated after the second oscillating signal is generated.