Bandgap voltage regulator

A bandgap voltage regulator is arranged such that, when a desired output voltage is present between its output and common terminals, current densities in a pair of bipolar transistors having unequal emitter areas are maintained in a fixed ratio. The difference in the transistors' base-emitter voltages is across a resistor, which thus conducts a PTAT current. The regulator also generates a CTAT current, and both the PTAT and CTAT currents are made to flow in another resistor, with the resulting voltages added by superposition. The regulator's resistors are sized such that Vout is an integral or fractional multiple of Vbg, where Vbg is the bandgap voltage for the fabrication process used to make the regulator's transistors, such that Vout is temperature invariant, to a first order. The resistors are preferably realized using unit resistors having a predetermined resistance, or series and/or parallel combinations of unit resistors.