A bandgap reference voltage generator includes, in part, a first
closed-loop circuit having a first operational amplifier and adapted to
generate a first current with a positive temperature coefficient and a
second closed-loop circuit having a second operational amplifier and
adapted to generate a second current with a negative temperature
coefficient. The bandgap reference voltage generator is further adapted
to include a multitude of output stages. Each output stage may be
independently scaled to sum any selected multiple of the first current to
any selected multiple of the second current to generate an output voltage
having either a nearly zero, a positive or a negative temperature
coefficient. For example, the first output stage may be scaled to
generate a reference output voltage with a nearly zero temperature
coefficient. Similarly, the second output stage may be scaled to generate
a reference output voltage with a negative temperature coefficient.