PCMCIA power interface

A PCMCIA power interface device for providing a voltage to a PCMCIA card coupled to an output terminal of said interface device, said interface device comprising:

• an N-channel MOSFET switching device having first and second terminals and a control terminal, said first terminal being coupled to receive said voltage, said second terminal being coupled to said output terminal;
• a discharge circuit coupled to said gate of said switching device for turning off said switching device, said discharge circuit including a capacitor for incrementally discharging said gate of said switching device and further comprising:
• a first transistor having a source, a gate, and a drain, said drain being coupled to said gate of said switching device, said source being coupled to a first terminal of said capacitor;
• a second transistor having a source, a gate, and a drain, said drain being coupled to said source of said first transistor, said source being coupled to a second terminal of said capacitor and to a first potential;
• and
• a logic circuit coupled to said gates of said first and second transistors, said logic circuit controlling the on and off states of said first and second transistors such that said capacitor incrementally discharges said gate of said switching device from so as to turn said switching transistor;
• a charge pump coupled to said gate of said switching device, said charge pump comprising a plurality of parallel-connected capacitors for incrementally charging said gate of said switching device such that said switching device gradually turns on, wherein the charging rate of said gate of said switching device is proportional to the ratio of capacitances of said plurality of capacitors and said gate of said switching device;
• a plurality of Schottky diodes, wherein each of said plurality of Schottky diodes is connected between an associated two of said parallel-connected capacitors;
• and
• a clamp diode coupled between a cathode of one of said plurality of Schottky diodes and a second potential, said clamp diode comprising:
• a semiconductor substrate of a first conductivity type having formed on a portion thereof a buried layer of a second conductivity type;
• an epitaxial layer of said second conductivity type overlying said buried layer and said substrate;
• and
• an isolation region of said first conductivity type extending from a top surface of said epitaxial layer and contacting said buried layer, wherein said isolation region and said buried layer serve as an anode and a cathode of said clamp diode, respectively, said epitaxial layer having formed on a portion thereof a metal layer serving as an anode of said Schottky diode, said epitaxial layer serving as said cathode of said Schottky diode.