Self-calibrating operational amplifier
US6242974A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 2, 1999 |
| Grant date | Jun 5, 2001 |
| Priority date | — |
| Expiry date | Aug 2, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01K7/01
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A stable, reliable, op-amp circuit overcomes the adverse affect of input offset voltages, V.sub.OSI, present at the input of op-amp. In one application, such VOSI-compensated op-amps employ a standard bandgap voltage input to achieve an improved voltage regulated reference source. A new circuit combination includes an auto-zero circuit arrangement intermediate an input network and the op-amp exhibiting the input voltage offset. In an auto-zero mode, the new auto-zero circuit arrangement samples the op amp's V.sub.OSI and redistributes the sampled signal in a storage network for use in compensating for the V.sub.OSI while operating in a normal mode. As the potential for V.sub.OSI problems again develops, another auto-zero pulse causes the circuit arrangement to switch again to the auto-zero mode and the cycle continues. Because the auto-zero arrangement employs the actual V.sub.OSI encountered in a specific op-amp, and that value for V.sub.OSI is used to null the error-causing input, the circuit arrangement is self-calibrating. If changes in environmental conditions tend to cause a particular V.sub.OSI to be encountered, then it is that value for V.sub.OSI that is nulled.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.