On-chip zero-temperature coefficient current generator

摘要

Embodiments of the invention generally provide generating a ZTC current using resistors that may be integrated into an IC, even if these resistors vary with temperature. Specifically, instead of applying a bandgap voltage across a ZTC resistor, the bandgap voltage may be applied to a temperature-dependent resistor to generate a first current that varies (either proportionally or complementary) with temperature. Additionally, a second current may be generated which compensates for the temperature variance of the first current. If the two currents change in the same manner relative to temperature (i.e., the respective slopes of the currents are the same when the underlying circuit elements are exposed to the same temperature variations), the difference between the currents remains constant. Thus, subtracting the two currents, regardless of the current temperature, results in a ZTC current—i.e., a current that is independent of temperature variations.

主权项

1. A method for generating a zero-temperature coefficient (ZTC) current, the method comprising:
generating a first temperature dependent current by applying a temperature independent voltage generated by a bandgap voltage generator to a first resistor, wherein the first resistor is included within an integrated circuit; generating a control parameter using the bandgap voltage generator; generating, based on the control parameter, a second temperature dependent current, wherein the first and second temperature dependent currents change at a rate that is substantially the same in response to temperature changes in the integrated circuit; and generating the ZTC current by subtracting the first and second temperature dependent currents.