Browse Prior Art Database

DSC Power-up Initialization Circuitry

IP.com Disclosure Number: IPCOM000107232D
Original Publication Date: 1992-Jan-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 1 page(s) / 43K

Publishing Venue

IBM

Related People

Holstein, WH: AUTHOR [+3]

Abstract

A DSC circuit for power-up initialization is disclosed. This circuit can be used to preset an arbitrary circuit to a specific state during chip power-up.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 99% of the total text.

DSC Power-up Initialization Circuitry

      A DSC circuit for power-up initialization is disclosed. This
circuit can be used to preset an arbitrary circuit to a specific
state during chip power-up.

      The initialization circuitry consists of two parts, a power
supply sense circuit and a set-reset latch.  The circuitry for a
3.6-volt power supply is shown in the Figure.  The phase of the
differential output of this circuit is a function of the power supply
voltage.  A threshold is determined by the ratio between resistance
values R3 and R4, and the voltage clamp at node REF1.  When the power
supply voltage is below this threshold, node 10 will be higher than
node 11.  When the power supply voltage is above the threshold, node
11 will be higher than node 10.

      The output of the power supply sense circuit is used to control
the set-reset latch, in this case using the reset input.  During the
power-up cycle, the initial state of the reset line driven by the
power supply sense circuit will be high, clearing the latch.  As the
power supply crosses the threshold level, this line will go inactive,
allowing the latch to be set by other logic.

      Once the power-up sequence has been completed, the set-reset
latch will be in a known state.  The output of this latch can then be
used to initialize other functions as required for proper operation
of the logic.

                            (Image Omitted)

      Disclosed a...