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Stored Charge Current Switch

IP.com Disclosure Number: IPCOM000077252D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Bono, RC: AUTHOR

Abstract

This circuit will provide a delay analogous to a delay line. With the input at -V volts, transistor Q2 conducts and draws current through resistor R1 and diode D1 so that the base of transistor Q3 is held down. Transistor Q4, therefore, conducts and provides an up output at the emitter of transistor Q5.

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Stored Charge Current Switch

This circuit will provide a delay analogous to a delay line. With the input at - V volts, transistor Q2 conducts and draws current through resistor R1 and diode D1 so that the base of transistor Q3 is held down. Transistor Q4, therefore, conducts and provides an up output at the emitter of transistor Q5.

When, at time T1, the base of transistor Q1 is raised to zero volts, transistor Q1 conducts thereby turning transistor Q2 off. Since diode D1 is a hot-carrier diode, current continues to flow for a period D after transistor Q2 is turned off. This current flows through diode D2 to ground to maintain the collector of transistor Q2 at a down level. Therefore, the base of transistor Q3 remains down and consequently the output at the emitter of transistor Q5 remains up. Eventually however, the charge on diode D1 is dissipated, and voltage at the collector of transistor Q2 rises, turning transistor Q3 on and transistor Q4 off, thereby causing the output potential at the emitter of transistor T5 to drop.

After the charge on diode D1 is dissipated, diode D2 is maintained conducting by current flowing through resistor R1. Now, when the input to transistor Q1 is again turned to its down state, -V volts, diode D1 turns on drawing current through resistor R1 and reverse current through diode D2. The stored charge on diode D2 maintains the potential at the collector of transistor Q2 at its up level for some time after the input has been turned off...