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High Power Conduction Cooled Resistor for Switching Regulators

IP.com Disclosure Number: IPCOM000103439D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 43K

Publishing Venue

IBM

Related People

Gordon, JC: AUTHOR [+4]

Abstract

Disclosed is a low inductance, high power, thick film resistor on a thick alumina substrate. The low inductance is accomplished by the resistor pattern layout and the close proximity to the ground plane, taking advantage of mirror imaging currents.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

High Power Conduction Cooled Resistor for Switching Regulators

      Disclosed is a low inductance, high power, thick film resistor
on a thick alumina substrate.  The low inductance is accomplished by
the resistor pattern layout and the close proximity to the ground
plane, taking advantage of mirror imaging currents.

      This resistor is used in a switching regulator incorporating
full wave bridge MOSFET drive technology.  It is located in the
snubber circuit which is across the primary of the main output
transformer.  It is used to snub the primary voltage during the dwell
time of the MOSFET switches.

      As shown in the figure, this high power resistor consists of a
thick film resistor 1 deposited on a thick alumina base 2.  The
alumina base 2 is 5 mm thick to withstand the thermal stresses from
initial turn-on and the mounting stresses incurred.  By having the
thick alumina base 3, the UL & CSA safety spacings are inherently
met. For connection to the resistor 1, terminals 3 are soldered to
pads at the resistor ends and extend onto a plastic terminal block 4.
The terminal block 4 is two levels with threaded inserts which
provide connection for two printed circuit cards and their extraneous
circuits, thus connecting the resistor to the snubber circuit.

      Disclosed anonymously.