Voltage regulator with current limiting circuitry

Claim 1

A voltage regulator having current limiting circuitry and receiving an unregulated input voltage from an electrical energy source and supplying a regulated D.C. voltage at its output, said voltage regulator comprising: an operational amplifier means having an inverting input terminal, a noninverting input terminal and an output terminal, said operational amplifier having a substantially high output impedance; reference voltage circuit means, connected as an input signal to said noninverting input terminal of said operational amplifier, for providing a reference voltage thereto; power amplifier controlling means, connected to said electrical energy source and said output terminal of said operational amplifier means, for providing a regulated DC output voltage at its output; means for connecting said output of said power amplifier controlling means as an input signal to said inverting input terminal of said operational amplifier means, with said operational amplifier providing at its output terminal an output signal that is the difference between said two input signals connected thereto; overcurrent detection means, having on and off states, for detecting when the current drawn by a load exceeds a predetermined magnitude, said output of said overcurrent detection means being connected to said output terminal of said operational amplifier, said overcurrent detection means being operative to lower the magnitude of the output voltage of said operational amplifier means when said current drawn by said load exceeds said predetermined magnitude; integrating means, connected to said output terminal of said operational amplifier means, for providing an average value of said magnitude of said output voltage of said operational amplifier means; and feedback means, connected between said output terminal and said inverting input terminal of said operational amplifier means, for feeding back a portion of the magnitude of said output voltage of said operational amplifier means so as to modify the gain of said operational amplifier and cause a linear reduction in said magnitude of said output voltage of said operational amplifier means which acts, through said power amplifier controlling means, to linearly reduce the magnitude of the output current of said voltage regulator to a level sufficient to remove said overcurrent condition.