Temperature and process independent exponential voltage-to-current converter circuit
US6369618B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 24, 2000 |
| Grant date | Apr 9, 2002 |
| Priority date | — |
| Expiry date | Jan 24, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05F1/562
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A voltage to current conversion circuit is described. The circuit comprises a first differential amplifier for receiving an input voltage and producing an output voltage, and a second amplifier for converting the output voltage of the first amplifier to a current. The transfer function of the voltage to current conversion circuit is proportional to an exponential function that depends on the input voltage. The circuit is temperature and process independent. In a first preferred embodiment, the first amplifier comprises a first transistor for receiving an input voltage at its base terminal, a temperature dependent current source coupled to the emitter of the first transistor, and a positive voltage supply coupled to the collector through a diode coupled transistor, and a second transistor paired with the first transistor and having a base terminal coupled to an input voltage terminal, an emitter coupled to a temperature dependent current source, and a collector coupled to a voltage supply. The output voltage is a differential signal taken from the collector terminals to the second amplifier, which comprises a third transistor coupled to a fixed current source, the base terminal for …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.