Temperature independent reference circuit
US7893754B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 2, 2009 |
| Grant date | Feb 22, 2011 |
| Priority date | — |
| Expiry date | Oct 2, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05F3/30
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A temperature independent reference circuit includes first and second bipolar transistors with commonly coupled bases. First and second resistors are coupled in series between the emitter of the second bipolar transistor and ground. The first and second resistors have first and second resistance values, R1 and R2, and third and second temperature coefficients, TC3 and TC2, respectively. The resistance values being such that a temperature coefficient of a difference between the base-emitter voltages of the first and second bipolar transistors, TC1, is substantially equal to TC2×(R2/(R1+R2))+TC3×(R1/(R1+R2)), resulting in a reference current flowing through each of the first and second bipolar transistors that is substantially constant over temperature. A third resistor coupled between a node and the collector of the second bipolar transistor has a value such that a reference voltage generated at the node is substantially constant over temperature.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.