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Protection of Printed Circuit Cards

IP.com Disclosure Number: IPCOM000086594D
Original Publication Date: 1976-Oct-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 73K

Publishing Venue

IBM

Related People

Hammer, JR: AUTHOR [+2]

Abstract

Several approaches are described for the protection of printed-circuit cards in the event that components, e.g., tantalum capacitors, become shorted.

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Protection of Printed Circuit Cards

Several approaches are described for the protection of printed-circuit cards in the event that components, e.g., tantalum capacitors, become shorted.

Referring to Fig. 1, one approach provides a rearrangement of the line pattern between connector 1 of a logic card 2 and capacitor 3 so that a discrete precision fuse 4 may be placed in series with the voltage line 5 to the capacitor. Fuse 4 is designed to be compatible with industrial standards for hole spacing on printed-circuit cards. It may be formed by encapsulating an extruded element formed in a loop, as in Fig. 2. The repair of components end the introduction of changes during early phases of a product design cycle are facilitated. This capability eliminates the need to go back through the card layout procedure for "fine-tuning" type design changes.

As shown in Fig. 3, the artwork for etching the card surface pattern can be changed to provide a narrow section in line 7 between the card connector contact 8, soldered on the edge of the card, and the first column 9 of apertures used for component mounting. In effect, this creates a fuse. Typically, on logic cards there are several voltage contacts to provide good voltage distribution. Therefore, each contact and line carries a proportionate part of the current required for the card. Depending on the component arrangement in the field of the card and the resultant current requirements per contact, it may be desirable to vary t...