Constant current r.f. generator
US4626767A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1984 |
| Grant date | Dec 2, 1986 |
| Priority date | — |
| Expiry date | Dec 21, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L5/00
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The present invention achieves constant voltage at radio frequencies to drive a constant voltage to constant current converter, by employing a tightly coupled d.c. feedback loop to control the voltage via a transformer to the drain of a FET operated as a Class C amplifier in the saturated mode whereby among other advantages, the amplifier can withstand, without damage, very high VSWRs. Control is affected by a high gain differential amplifier which compares a d.c. voltage derived from the r.f. output of the system against a highly stable d.c. voltage reference. A controller, responding to the output of the differential amplifier causes a first level of voltage to be applied to the drain of the FET when the system is not loaded and causes a second voltage varying between said first level and a higher level when the system is loaded. In the lower voltage condition the controller is effectively removed from the system so that it does not have to drop a high voltage to a low voltage; the low voltage being supplied effectively from a separate source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.