Browse Prior Art Database

High Current, Low Capacitance Surge Suppressor

IP.com Disclosure Number: IPCOM000102184D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Richardson, PJ: AUTHOR

Abstract

Any transients coming into the system via data lines will be clamped (transients can be either positive or negative in polarity) through either CRRH-1 (positive voltage) or CRRL-2 (negative voltage) down through CRCH or CRCL .

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High Current, Low Capacitance Surge Suppressor

       Any transients coming into the system via data lines will
be clamped (transients can be either positive or negative in
polarity) through either CRRH-1 (positive voltage) or CRRL-2
(negative voltage) down through CRCH or CRCL .

      CRRH and CRRL are low capacitance rectification diodes with
high surge capability.

      CRCH3 and CRCL4 are high current surge Zener diodes. Selection
of this diode's breakdown voltage will set the clamping voltage.

      RVL6 and RVH5 are biasing current-limiting resistors. Setting
Vc at a point below the  breakdown voltage allows the high
capacitance of the surge diodes 3,4 to be minimized.  RVL and RVH are
typically in the k ohm range, since current draw during quiescent
operation is small. During a surge, RVH and RVL limit the amount of
surge current dumped into the supply to milliamps.  This protects the
supply from damage.  Also, response time is reduced by having the
diodes biased.

      Rp7 is simply a series resistance or inductance to protect any
sensitive inputs or outputs. Note:  For units that are on the line
with power off, RVL, RVH, Vc should be omitted. Advantages:
           Low cost.
           Low capacitance.
           Can be used for many different transmission lines
           in one device with very low cost impact.
           Extremely fast (nanoseconds) response to transients.