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Variable Voltage From Product Under Test

IP.com Disclosure Number: IPCOM000035260D
Original Publication Date: 1989-Jun-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Beck, DL: AUTHOR [+2]

Abstract

During functional stress testing of system logic units in manufacturing test, systems are tested at the high and low voltage limits of the system specification. The need for a low-cost power source with adjustable variable voltage is satisfied by using a special combination of hardware and software. Thus, a low-cost system product regulator card can be used for stress testing.

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Variable Voltage From Product Under Test

During functional stress testing of system logic units in manufacturing test, systems are tested at the high and low voltage limits of the system specification. The need for a low-cost power source with adjustable variable voltage is satisfied by using a special combination of hardware and software. Thus, a low-cost system product regulator card can be used for stress testing.

A voltage regulator card was used as a variable voltage source during manufacturing testing which eliminated the requirement of three expensive commercial programmable power supplies. Before modification, the regulator card provided fixed voltages of + 5 and + 12 volts to the system. By applying an analog voltage (Vao) input to the + 5 and + 12 circuits, the voltage outputs from the regulator. Fig. 1 shows a block diagram of the voltage regulator card with the manufacturing modification of Rx and analog input voltage (Vao) added for stress testing.

Under normal operation of fixed voltage output with Rx and Vao removed, test point 1 (TP1) is held at 2.5 volts by the feedback loop and the current through R2 is constant. The current through R1 is equal to the current through R2, because the input current to the op- amp is negligible.

When Rx and Vao are added, TP1 will still be held at 2.5 volts and the current through R2 is the same, but we now can control the current through R1 by varying analog input voltage (Vao). When Vao is at 2.5 volts, the current through R1 and the output volta...