Temperature compensated RC oscillator for signal conditioning ASIC using source bulk voltage of MOSFET
US8044740B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 3, 2009 |
| Grant date | Oct 25, 2011 |
| Priority date | — |
| Expiry date | Dec 11, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K4/502
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A temperature compensated CMOS RC oscillator circuit changes the source-bulk voltage to stabilize the MOSFET's threshold voltage variation over temperature using a resistor and temperature-correlated bias current. The MOSFET's source is connected to ground through a resistor. This temperature-correlated bias current also runs through this resistor. When temperature increases, the bias current also increases, which increases the MOSFET's source-bulk voltage. The increased source-bulk voltage helps to stabilize the threshold voltage of MOSFET at high temperature. A power saving logic is also embedded in this oscillator to achieve higher frequency at lower power consumption. In the present invention, there is no high gain op amp or high speed comparator, which makes the resultant oscillator to be low power design and which can be integrated into a single chip with other system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.