Electrical regulator apparatus including a zero temperature coefficient voltage reference circuit

Claim 1

An electrical regulator circuit, comprising: an input terminal for receiving an unregulated input voltage; an output terminal; an adjustment terminal; means for developing a reference voltagE having a substantially zero temperature coefficient and including, a first terminal coupled to said input terminal, a second terminal, a third terminal, a first transistor having a first emitter coupled to said second terminal, a first collector coupled to said third terminal, and a first base coupled to said first collector, a second transistor having a second base coupled to said first collector, a second collector coupled to said third terminal, and a second emitter coupled to said second terminal, said first and second transistors having different current densities J1 and J2 respectively, whereby the base-to-emitter differential Delta VBE therebetween has a positive temperature coefficient and may be expressed as Delta VBE (kT/q)1n(J1J2) where k is Boltzmann''s constant, T is absolute temperature, and q is the charge on an electron, and circuit means having a negative temperature coefficient operatively combined with said first and second transistors to develop said reference voltage between said second and third terminals, a resistive impedance coupling said third terminal to said adjustment terminal; and voltage follower means operatively coupling said input terminal to said output terminal and having a first input terminal coupled to said second terminal and a second input terminal coupled to said adjustment terminal, said voltage follower means being responsive to a voltage developed at said adjustment terminal when said adjustment terminal is resistively coupled to a circuit ground and said unregulated input voltage is applied between said input terminal and said circuit ground, said voltage follower means being operative to develop a regulated voltage at said output terminal.