CMOS integrated circuit having precision resistor elements
US4868482A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 5, 1987 |
| Grant date | Sep 19, 1989 |
| Priority date | — |
| Expiry date | Oct 5, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H11/46
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A circuit is provided for realizing multiple precision resistor elements on an integrated circuit by sensing a reference resistor. The circuit contains a first current source which passes a first current through a reference resistor located either on or off of the integrated circuit to generate a reference voltage. The reference voltage is applied to the inverting input of a precision high gain operational amplifier. A second current source is connected to the drain of a first MOS transistor operating in its ohmic region. The second current source is also connected to the non-inverting input of the high gain operational amplifier. The output of the operational amplifier is electrically connected to the gate of the first and second MOS transistors. In operation, a precision resistance is developed across the second MOS transistor which is equal to or some determinable multiple of the resistance of the reference precision resistor located on or off chip. An operational amplifier adaptable to this circuit is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.