Stabilized low dropout voltage regulator circuit

Claim 1

A voltage regulator circuit having an unregulated input supply terminal, a regulated output supply terminal and a supply return terminal, said circuit being composed of transistors each one having controlled current flow electrodes of high and low impedance and a current flow control electrode, said circuit comprising: a series pass transistor having its low impedance electrode connected to said unregulated input supply terminal, its high impedance electrode connected to said regulated output supply terminal and a control electrode; means driven from said regulated output supply terminal and connected to said control electrode of said series pass transistor thereby creating an overall negative feedback loop that operates to develop a control potential that holds said regulated output supply terminal at a constant potential level that is substantially independent of temperature, input supply voltage and output supply terminal current; a shunt transistor having its low impedance electrode connected to said regulated supply output terminal, means for returning its high impedance electrode to said supply return terminal and a control electrode; and means, responsive to the current flowing in said shunt transistor, connected to said control electrode of said series pass transistor to form an internal negative feedback loop, within said overall negative feedback loop, said internal negative feedback loop being operative to hold the current flow in said shunt transistor constant and said regulator circuit is thereby stabilized.