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Noise Reduction in a Current Switch Receiver by Using a Parasitic Polysilicon Plate Capacitor

IP.com Disclosure Number: IPCOM000121384D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 29K

Publishing Venue

IBM

Related People

Bonges, HA: AUTHOR [+2]

Abstract

Naturally existing polysilicon plate capacitors are wired from one side of a current switch receiver to reference voltage Vr. Thus, noise spikes on Vr are reduced without requiring space occupancy by additional devices.

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Noise Reduction in a Current Switch Receiver by Using a Parasitic
Polysilicon Plate Capacitor

      Naturally existing polysilicon plate capacitors are wired from
one side of a current switch receiver to reference voltage Vr.  Thus,
noise spikes on Vr are reduced without requiring space occupancy by
additional devices.

      The figure is a schematic of a conventional current switch
receiver except for the addition of a connecting wire L between poly
plate P and the input of reference voltage Vr.  Without wire L, node
Vr has a noise spike due to transition of input IN above Vr which
switches current to NPN transistor Q2 and shuts off transistor Q3.
With wire L, a capacitor has been added between nodes Vr and Rc.  As
a consequence, opposite-going noise spikes on Rt and Vr tend to
cancel.

      Current source C is a conventional circuit.

      Disclosed anonymously.