Method and apparatus for compensating input threshold variations on input buffers
US6191626A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 2, 1999 |
| Grant date | Feb 20, 2001 |
| Priority date | — |
| Expiry date | Aug 2, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/00384
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for compensating for input threshold variations in input buffers is provided. The method and apparatus compensate for input threshold variations by applying a bias voltage on a known capacitance of an RC calibration circuit using, for example, a pulse width modulator. The bias voltage helps ensure that the time to charge the known capacitance from the bias voltage to the input threshold voltage of the input buffer is independent of the threshold voltage. The bias voltage is chosen using an iterative process in which the time to charge from the bias voltage to the threshold voltage is compared with a reference time. The bias voltage is adjusted based on the comparison.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.