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Voltage Dip Sensor

IP.com Disclosure Number: IPCOM000086720D
Original Publication Date: 1976-Oct-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Shelton, I: AUTHOR [+3]

Abstract

A voltage-dip sensor detects proper start up of a high-voltage supply and monitors the supply output for voltage dips which may occur after start up.

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Voltage Dip Sensor

A voltage-dip sensor detects proper start up of a high-voltage supply and monitors the supply output for voltage dips which may occur after start up.

The voltage-dip detector comprises the three parts shown in Fig. 1. Half- wave rectifier 11 allows the output waveform to be a sine or square wave, as well as a DC voltage. The rectified input voltage VA is provided to dip-detect circuit
13. The divided-down rectified input voltage VB is provided to the dip-detect circuit 13 and level-detect circuit 15.

Referring to Fig. 2, the time constant associated with capacitor C1 is small so that the rectified voltage tracks the peak input voltage. Amplifier 17 compares voltage VB with a predetermined voltage VF. Amplifier 19 compares divided- down voltage VC to voltage VB. The time associated with capacitor C2 is much larger than that of capacitor C1. Also, voltage VC is initially less than voltage VB. When the input voltage dips, voltage VA tracks the dip as does voltage VB, while voltage VC remains constant. When voltage VB falls below voltage VC, the output of the dip-detect circuit 13 goes low. Transistor 21 is a buffer stage which prevents the output of the circuit from going negative. The dip-detect circuit thus sets it own detection level for dip detecting from the initial input voltage and provides a logical output signal upon detection of a short duration voltage dip.

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