Method for detecting minimum operational frequency

• US 8,044,691 B2
• Filed: 05/21/2010
• Issued: 10/25/2011
• 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
• Primary Examiner(s): Donovan; Lincoln
• Assistant Examiner(s): Houston; Adam
• Application Number:
  US12/784,506
• Publication Number:
  US 20100231265A1
• Time in Patent Office: 522 Days
• Field of Search: 327/142, 327/143, 327/333
• US Class Current: 327/142
• 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, comprising;

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

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

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.

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

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

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

generating a logic signal to provide a level transition when a frequency of the first oscillating signal reaches a second predetermined frequency corresponding to the minimum operational frequency, comprising;

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.

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

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

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

generating a logic signal to provide a level transition when a frequency of the first oscillating signal reaches a second predetermined frequency corresponding to the minimum operational frequency, comprising;

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.

4. 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, comprising;

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.

5. The method of claim 4, 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.

6. The method of claim 5, 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.