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Circuit Card with Soft Power Switch

IP.com Disclosure Number: IPCOM000104933D
Original Publication Date: 1993-Jun-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Schmits, W: AUTHOR [+2]

Abstract

A circuit card 1 is disclosed for connection to a system by means of connector pins 1, 2, 3 positioned thereon. The circuit card comprises a soft power switch for reducing the power transient effects of inserting the card by gradually turning on a transistor T1. The gate voltage of transistor T1 is controlled by an RC component with a capacitor C1 and a resistor R1. If pin 3 is permanently connected to pin 2, transistors T3 and T2 are turned off, so that capacitor C1 is charged right after the circuit card has been connected to the system. If, on the other hand, pin 3 is open, transistors T3 and T2 are turned on and T1 remains off until a potential is applied to pin 3 from the system such that transistors T3 and T2 are turned off and C1 can be charged, with transistor T1 being turned on gradually.

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Circuit Card with Soft Power Switch

      A circuit card 1 is disclosed for connection to a system by
means of connector pins 1, 2, 3 positioned thereon.  The circuit card
comprises a soft power switch for reducing the power transient
effects of inserting the card by gradually turning on a transistor
T1.  The gate voltage of transistor T1 is controlled by an RC
component with a capacitor C1 and a resistor R1.  If pin 3 is
permanently connected to pin 2, transistors T3 and T2 are turned off,
so that capacitor C1 is charged right after the circuit card has been
connected to the system.  If, on the other hand, pin 3 is open,
transistors T3 and T2 are turned on and T1 remains off until a
potential is applied to pin 3 from the system such that transistors
T3 and T2 are turned off and C1 can be charged, with transistor T1
being turned on gradually.  Before removal of the card, transistor T1
can be turned off by applying a potential to pin 3.