US 12,066,476 B2
Systems and methods for duty cycle measurement
Tsung-Hsien Tsai, Taoyuan County (TW); Ruey-Bin Sheen, Taichung (TW); Chih-Hsien Chang, New Taipei (TW); and Cheng-Hsiang Hsieh, Taipei (TW)
Assigned to Taiwan Semiconductor Manufacturing Company, Ltd., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Company, Ltd., Hsinchu (TW)
Filed on Dec. 17, 2020, as Appl. No. 17/124,580.
Claims priority of provisional application 62/982,176, filed on Feb. 27, 2020.
Prior Publication US 2021/0270879 A1, Sep. 2, 2021
Int. Cl. G01R 29/02 (2006.01); G01R 25/00 (2006.01); H03K 3/037 (2006.01); H03K 5/00 (2006.01); H03K 19/21 (2006.01)
CPC G01R 29/023 (2013.01) [G01R 25/005 (2013.01); H03K 3/037 (2013.01); H03K 5/00 (2013.01); H03K 19/21 (2013.01); H03K 2005/00058 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for outputting a duty cycle value of a periodic input signal, the method comprising:
receiving the periodic input signal at a delay circuit configured to delay the periodic input signal based on a digital control word and to generate a delayed version of the periodic input signal, wherein each of the periodic input signal and the delayed version of the periodic input signal includes a plurality of periods, each period having high and low portions;
generating a first digital control word used to delay the periodic input signal a first amount of time corresponding to a period of the periodic input signal such that a duration of a high or low portion of a period of a first delayed version of the periodic input signal is substantially equal to a total duration of high and low portions of a period of the periodic input signal;
generating a second digital control word used to delay the periodic input signal a second amount of time corresponding to a portion of the period that the periodic input signal has a logic-level high value;
generating a third digital control word used to delay the periodic input signal a third amount of time corresponding to a portion of the period that the periodic input signal has a logic-level low value;
calculating a value of a duty cycle of the periodic input signal based on the first, second, and third digital control words; and
outputting the calculated duty cycle value.