Browse Prior Art Database

Current Mirror Emitter Follower Driver

IP.com Disclosure Number: IPCOM000049356D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

Chan, YH: AUTHOR [+2]

Abstract

Disclosed in Fig. 1 is a current switch receiver circuit with a current-mirror emitter follower as the output stage. The circuit is designed to be used as an address true-complement generator in high performance random-access memories. It receives around ground inputs and gives high power double dual-phase outputs to drive address decoders (not shown).

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Current Mirror Emitter Follower Driver

Disclosed in Fig. 1 is a current switch receiver circuit with a current-mirror emitter follower as the output stage. The circuit is designed to be used as an address true-complement generator in high performance random-access memories. It receives around ground inputs and gives high power double dual- phase outputs to drive address decoders (not shown).

In high performance, high density random-access memories, current switch address decoders are often used. The address true-complement generators have to drive a large number of base inputs. Due to this large fan-out, in order to have satisfactory down-going transition on the address lines, pull-down current (Ipd) from the address circuits has to be very high (typically in excess of 10 mA per address line). With conventional emitter follower (E.F.) (designs (Figs. 2A and 2B), the input current switch stage has to drive a total of more than 20 mA through the two emitter followers. This excessive loading not only slows down the circuit during an address up-going transition, it also demands high current capability on the E.F. devices.

A solution to the above problem is to use a Darlington configuration in the output stage. However, due to the extremely high gain of the Darlington transistor, the circuit will become unstable and thus not suitable to be used as address receivers. The problem can be overcome by utilizing a current mirror technique in the driving stage of the receive...