Patent ID: 7705662
Filing Date: 2010-04-27
Classification: G05F

Abstract:
1. A temperature-compensated reference-voltage generator comprising: a first stage that generates a complementary-to-absolute-temperature current that increases as temperature decreases; a second stage that generates a proportional-to-absolute-temperature current that increases as temperature increases; a summing resistor that receives both the complementary-to-absolute-temperature current from the first stage and the proportional-to-absolute-temperature current from the second stage, the summing resistor generating a summing voltage that is less dependent on temperature than either the complementary-to-absolute-temperature current or the proportional-to-absolute-temperature current; a final voltage divider, in the second stage, that generates a reference voltage that includes the summing voltage; an output transistor, coupled to the final voltage divider, for driving current to an output node, the output node being a node between the output transistor and the final voltage divider, the output node being driven by the output transistor to maintain the reference voltage on the output node; and a final op amp having an output that drives a gate of the output transistor, the final op amp having a first input connected to a first sensing node in the second stage, and a second input connected to a second sensing node in the second stage; wherein the first stage further comprises: wherein the first reference transistor is a bipolar transistor having a base and a collector tied together and an emitter connected to the first reference transistor and to the first voltage divider; wherein an emitter voltage of the first reference transistor is a voltage that falls with increasing absolute temperature, whereby the reference voltage includes the summing voltage that sums the complementary-to-absolute-temperature and proportional-to-absolute-temperature currents.