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Pulsed High Voltage Resistor Trimmer

IP.com Disclosure Number: IPCOM000093369D
Original Publication Date: 1967-Sep-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Greenman, JM: AUTHOR [+3]

Abstract

The system produces and controls a train of pulses of increasing amplitude, for trimming resistors by lowering their bulk resistivity. The bulk resistivity of resistive films of semiconductive material with a silver or silver alloy additive can be lowered to a desired value. This is effected by subjecting the film to high-intensity pulses of very short duration.

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Pulsed High Voltage Resistor Trimmer

The system produces and controls a train of pulses of increasing amplitude, for trimming resistors by lowering their bulk resistivity. The bulk resistivity of resistive films of semiconductive material with a silver or silver alloy additive can be lowered to a desired value. This is effected by subjecting the film to high- intensity pulses of very short duration.

In a system employed for trimming resistors in this manner, the output of nanosecond pulse generator 11 is applied to resistor 12 under trim. Generator 11 is a three-step system which stores energy in a choke, discharges the energy and stores it at a higher voltage in a capacitor, and discharges this high voltage through a step-up pulse transformer to the resistor under trim. Cycling system 13 contains a controllable frequency voltage generator for operating the pulse forming relay in generator 11.

Resistor 12 is one arm of a measuring bridge 14, the opposite arm being a standard resistor of the desired value. Differences between the value of resistor 12 and the standard resistor are fed, via an operational amplifier, back to integrating current controller 15 and an automatic turnoff circuit 16. Power is fed to controller 15 by a constant voltage power supply 17.

The amount of trim is proportional to the increase in pulse amplitude. Thus, controlling the rate at which the pulse amplitude increases determine the rate of trim. Controller 15 increases the pulse amplitude...