Browse Prior Art Database

Delta I Suppressor

IP.com Disclosure Number: IPCOM000085780D
Original Publication Date: 1976-Jun-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Gersbach, JE: AUTHOR

Abstract

Described is a simple addition to transistor-transistor logic (TTL) driver circuits that will eliminate the load changes in a power supply. The circuit thus shares a common current between circuits to reduce power.

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Delta I Suppressor

Described is a simple addition to transistor-transistor logic (TTL) driver circuits that will eliminate the load changes in a power supply. The circuit thus shares a common current between circuits to reduce power.

Transistors T2, T3, and T4, diodes D1 and D2 and resistors R0, R1, R3, R4 and R5 all comprise a standard TTL driver circuit with the input voltage Vin at node 1 to transistor T2 and the output voltage Vout taken at node 2. The circuit shown can be, for example, an off-chip driver for a memory chip with most of the on-chip power derived at node Vsx. Since there can be a large number of such driver circuits on the chip, it is desirable to use the same current in other circuits 10 connected between +VS and node Vsx. The power is then one half of the power normally required without such sharing.

A major problem of this arrangement is the change in current in resistor R1 which can disturb the other circuits coupled to node Vsx. By coupling the collector of transistor T1 to node Vsx, its base to the base of transistor T3 and its emitter to ground through an emitter resistor R2 equal in value to resistor R1, any load change can be compensated for.

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