Browse Prior Art Database

Clock Chopper On-Chip Delay and Measurement Technique

IP.com Disclosure Number: IPCOM000099180D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Document File: 4 page(s) / 95K

Publishing Venue

IBM

Related People

Gupte, NB: AUTHOR [+2]

Abstract

A method has been proposed to measure circuits in devices which are not easily accessed and are not responsive to normal test techniques. The suggests conversion of a difficult analog into a frequency, digital technique which excellent accuracy and ease of measurements.

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Clock Chopper On-Chip Delay and Measurement Technique

       A method has been proposed to measure circuits in devices
which are not easily accessed and are not responsive to normal test
techniques.  The suggests conversion of a difficult analog into a
frequency, digital technique which excellent accuracy and ease of
measurements.

      Clock chopper delay and pulse width are extremely to measure.
The two parameters cannot be obtained from either an automated
statistic transient program or by direct measurement.  This proposal
measuring both the delay and pulse width on the utilizing the
frequency measurement technique, McLeod *.

      In a clock chopper book (Fig. 1) D1 is the delay through time
delay blocks (TD BLKs) and D2 is the delay through CLK DVR, an "OR"
gate.  For the proposed technique, the at point A is assumed to be at
a low level.  The diagram at points B, C and D of Fig. 1 is
given in 2.  From the latter:
        D2f + PW = D1f + D2r
        PW = D1f + D2r - D2f
        clock chopper delay = D2f
   where
        PW = pulse width out of the clock chopper
        D1f = fall delay through the TD BLKs
        D2r = rise delay through the CLK DVR
        D2f = fall delay through the CLK DVR

      The path shifting oscillator (PSO) diagram of Fig. 3 is the
same clock chopper book of Fig. 1 except that the between points B
and E is broken.  There are paths where path r is the reference path.
 BLK 1 and 2 are characterized in the reference path and are common
all other paths.  Paths 1 and 2 are unknown.  In path 1, A is held
at a low level with point E held at a high  In path 2, points
A and B are both held at a low  By selecting the paths one at
a time, three path frequency measurements are made.  Two beat are
also measured with path r as the reference  The clock chopper delay
and pulse widt...