Patent ID: 6331767
Filing Date: 2001-12-18
Classification: G05F

Abstract:
An input circuit for a voltage regulator comprising:a control device having an input terminal and an output terminal, said control device responsive to an enabling signal applied to said input terminal to generate a control voltage at said output terminal;a n-channel MOSFET having a gate terminal connected to said output terminal of said control device, said MOSFET also having a drain terminal adapted to be connected to a power supply and a source terminal adapted to be connected to a voltage regulator input terminal, said MOSFET being initially in a non-conductive state to prevent current from flowing from said power supply to said voltage regulator and said MOSFET being responsive to said control voltage to change to a conducting state to allow an electric current to flow between said drain and source terminals; anda zener diode having an anode and a cathode, said anode being connected to said gate terminal of said MOSFET to limit said control voltage such that said MOSFET progressively reduces the current flowing between said drain and source terminals when the power supply voltage increases above a predetermined level.