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Rapid Response Power Cut-Off Circuit

IP.com Disclosure Number: IPCOM000103293D
Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 42K

Publishing Venue

IBM

Related People

Caston, FE: AUTHOR [+2]

Abstract

A common method of cooling high performance integrated circuit chips during test is to immerse the chips in a pool of (dielectric) liquid and allow boiling to take place. As the heat flux is increased, the quantity of vapor produced increases up to a point where the entire chip is blanketed in vapor. The heat flux at this point is called the Critical Heat Flux, and it is associated with a sudden and large rise in the circuit temperature. The resulting temperature can be detrimental to the chip.

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Rapid Response Power Cut-Off Circuit

      A common method of cooling high performance integrated circuit
chips during test is to immerse the chips in a pool of (dielectric)
liquid and allow boiling to take place.  As the heat flux is
increased, the quantity of vapor produced increases up to a point
where the entire chip is blanketed in vapor.  The heat flux at this
point is called the Critical Heat Flux, and it is associated with a
sudden and large rise in the circuit temperature.  The resulting
temperature can be detrimental to the chip.

      A circuit has been devised which detects this sudden rise in
temperature and deactivates the power supplies, thereby saving the
chip from damage.  As the temperature increases, the resistance of
the temperature sensing diodes on the chip decreases.  A circuit
which provides a constant voltage across the sensing diodes then
experiences an increase in current.  The rate of increase in the
current is proportional to the rate of increase in diode temperature
and can be converted to a voltage using components with complementing
functions, i.e., simulated inductance.

      The block diagram shows the circuit used to protect thermal
test vehicles.  The first stage is an active differentiator that
converts current to voltage.  The second stage contains filtering
which prevents false triggering and provides the necessary signal
conversion to drive the crowbar of the power supplies used.

      Disclosed anonymously....