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Browse Prior Art Database

Power Line Dip Sensor

IP.com Disclosure Number: IPCOM000073755D
Original Publication Date: 1971-Jan-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Chorpenning, JS: AUTHOR [+3]

Abstract

This power line dip sensor monitors the unregulated bulk voltage and provides a warning signal if the absolute value of the unregulated voltage becomes less than the trip point of the power line dip sensor. The power line dip sensor senses the voltage difference between the unregulated bulk voltage and the regulated voltage from the voltage regulator output.

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Power Line Dip Sensor

This power line dip sensor monitors the unregulated bulk voltage and provides a warning signal if the absolute value of the unregulated voltage becomes less than the trip point of the power line dip sensor. The power line dip sensor senses the voltage difference between the unregulated bulk voltage and the regulated voltage from the voltage regulator output.

Transistors T1 and T2 comprise a differential sensing element and transistors T3 and T4 are the output stages of the circuit. The sensing input A1 is connected to the unregulated bulk voltage. The reference voltage input B1 is connected to the output of the voltage regulator. At the power line dip sensor's trip point, both the unregulated bulk voltage and the regulated voltage are within 10% of each other.

Under normal conditions, sensing input A1 is several volts more negative than the -39.4V trip point of the power line dip sensor. Under these conditions, transistors T1 and T3 are normally on and transistors T2 and T4 are normally off. The base voltage of transistor T2 is held more positive than -36V by the voltage drop across diode D2. The base voltage of transistor T1 is determined by the voltage sensed at sensing input A1 and is more negative than the base voltage of transistor T2.

When a power line dip occurs, sensing point A1 rises toward ground, past the -39.4V trip point of the power line dip sensor. When this occurs, transistor T1 turns off and transistor T2 turns on. The volta...