Voltage-clamping device and operational amplifier and design method thereof
US7595690B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 2008 |
| Grant date | Sep 29, 2009 |
| Priority date | — |
| Expiry date | Jun 10, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45636
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A voltage-clamping device used in an operational amplifier is provided. The operational amplifier comprises a first transistor. The cross-voltage between the gate and the source of the first transistor is near to a specific voltage and the cross-voltage between the drain and the source of the first transistor is not equal to zero, so as to generate a big substrate current. The voltage-clamping device comprises a second transistor whose source and gate are respectively coupled to the drain of the first transistor and used for receiving a bias signal, so that the second transistor is biased in saturation region, and the voltage at the source of the second transistor is made equal to the difference between the bias signal and the threshold voltage of the second transistor. Thus, the cross-voltage between the drain and the source of the first transistor is reduced and the substrate current is reduced accordingly.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.