International Business Machines Corporation

John C Ceccherelli

Thomas M Cowell

Stephen R Scandalis

A power supply control circuit for conditioning an electronic circuit's input voltage at ground or at the operation voltage of an external power supply so as to permit the electronic circuit to receive a supply voltage at ground potential until the power supply transitions above a threshold voltage level and thereafter to provide operation level voltage of the power supply to the electronic circuit. The circuit comprises a transconducting means having its high current node coupled to an external power supply, its controlling node coupled to a voltage reference means. The transconducting means has its controlled high current node coupled through a power input node to the power input for the electronic circuit to condition the voltage received thereby. The power input node is in turn coupled through a pull down means to ground potential.

Power supply control circuit

A method and apparatus for sequencing the operation of electronic circuits based upon the level of the voltage provided by an external power supply. One or more power supply sequencer circuits may be interposed between an external power supply and one or more electronic circuits. The power supply sequencer circuits comprise a transistor having its high current node coupled to an external power supply, its controlling node coupled to a voltage sequencing means such as a diode and a resistor, wherein the resistor is in turn coupled to the external power supply and the diode is coupled to the ground potential. The transistor has its controlled high current node coupled through a power input node to the power input for the electronic circuit to condition the voltage received thereby. The power input node is in turn coupled through a second resistor to ground potential. The power sequencer circuits set a sequenced voltage level for transitioning the potential supplied to the electronic circuits from the ground potential to the operating potential of the power supply. Multiple versions of the power supply sequencers may be used to enable the sequential operation of an entire system during power supply transitions.

Power supply controlled operation sequencing method and apparatus

A system and method of providing a temperature compensated line termination for a high speed communications bus meeting military standards specifications. A temperature compensating device exhibiting a negative temperature coefficient of resistance is connected between a power supply and the communications bus drives. In a preferred embodiment, a P-N junction in series with a Schottky diode is placed between a 3.3 volt supply and the communications bus drive modules.

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Wappingers Falls, NY, United States of America

John C Ceccherelli