Function generator
US5719533A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 26, 1996 |
| Grant date | Feb 17, 1998 |
| Priority date | — |
| Expiry date | Sep 26, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L1/022
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
In order to realize highly accurate temperature compensation of a crystal oscillation frequency, a current in proportion to the cube of a difference between an ambient temperature T.sub.a and a reference temperature T.sub.0 is generated. For this purpose, provided are a first series circuit of two diodes; a second series circuit of three diodes; a third series circuit of two diodes; a fourth series circuit of three diodes; a current source for allowing a constant current to flow into the first series circuit; a current source for allowing a constant current to flow from the third series circuit; a current source for allowing a current in proportion to T.sub.a -T.sub.0 to flow into the second series circuit when T.sub.a .gtoreq.T.sub.0 and allowing a current in proportion to .vertline.T.sub.a -T.sub.0 .vertline. to flow from the fourth series circuit when T.sub.a <T.sub.0 ; an NPN transistor and a PNP transistor whose collectors are connected with an output terminal; and two operational amplifiers for applying a voltage between the anode terminals of the first and second series circuits between the base and the emitter of the NPN transistor and for applying a voltage between the cat…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.