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Low Voltage Current Controlled Gate

IP.com Disclosure Number: IPCOM000048988D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 3 page(s) / 27K

Publishing Venue

IBM

Related People

Banker, DC: AUTHOR [+3]

Abstract

The low voltage current-controlled gate (CCG) depicted in Fig. 1 operates over a wide range of power supply voltages, thus increasing reliability and versatility. Low Vf Schottky barrier diode (SBD) input gates allow operation on as low es 1.4 volts by lowering the input threshold to provide a better match for lower output levels.

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Low Voltage Current Controlled Gate

The low voltage current-controlled gate (CCG) depicted in Fig. 1 operates over a wide range of power supply voltages, thus increasing reliability and versatility. Low Vf Schottky barrier diode (SBD) input gates allow operation on as low es 1.4 volts by lowering the input threshold to provide a better match for lower output levels.

DC statistical analysis was performed varying temperature and power supply from Tj=25 to 100 degrees C and from VC=1.4 to 1.6 volts, respectively. Transient analysis shows substantial improvements in speed, transition time and waveform quality over those of TTL circuits of equivalent power dissipation.

Fig. 2 is a block diagram of computer-aided analysis, Fig. 3 shows output waveforms, and Fig. 4 is a speed/power curve.

The superior performance of the disclosed low voltage CCG circuit is based primarily on the action of coupling transistor T2 (Fig. 1). When T1 is off, current from RV charges the base-collector junction capacitance of T2. This junction accumulates charge, while preventing heavy conduction of T4, since the built-in voltage of a base-collector junction is lower than that of a base-emitter junction. The voltage across R4 is negligible because R3 is much larger than R4.

When all inputs A, B, C go up, phase-splitter transistor T1 turns on and its collector becomes less positive, turning emitter follower T3 off. Diode D4 prevents saturation of T1. The emitter of T1 goes more positive and forces the charge across the base-collector capacitance of T2 into the base of T4, causing heavy...