Browse Prior Art Database

Servo Loop Control of Pulse Driver Levels

IP.com Disclosure Number: IPCOM000118465D
Original Publication Date: 1997-Feb-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 4 page(s) / 74K

Publishing Venue

IBM

Related People

Wochele, F: AUTHOR

Abstract

Disclosed is a method which adds high accuracy to the levels of ordinary pulse drivers.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 53% of the total text.

Servo Loop Control of Pulse Driver Levels

      Disclosed is a method which adds high accuracy to the levels of
ordinary pulse drivers.

      Fig. 1 shows a block diagram of a pulse driver.  Uli and Dli
are DC voltage inputs which control the Up-Level respectively
Down-Level of the driver output.

      An ideal driver will respond exactly with the same levels
applied to its Uli, Dli inputs.  However, practical circuits show
deviations of the ideal values, which may have positive or negative
signs and vary with temperature, duty-cycle, and magnitude of the
Uli, Dli inputs.  It is common practice to keep this variation with
high technical effort as small as possible in order to obtain more
accurate output levels.  Even with high effort, it is not possible to
achieve the same accuracy as with the described method.

      In Fig. 2, a control circuit is added, which corrects the Uli
input of the driver in such a way that the actual Up-level of the
driver output is almost exactly identical to the Ul input.  For more
clarity, the Down-level is not shown.  The driver together with the
control-circuit is a time discrete servo loop.

Functional Description of the Control Circuit:

      The up/down counter is clocked with the delayed positive
transition of the IN signal (Inp A).  The delay allows the driver to
settle at its Up-level before any action is taken.  If the output of
the driver (Inp B) is lower than Ul, the counter is put in a count-up
mode vi...