Active bias for a pulsed power amplifier
US5451907A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 1994 |
| Grant date | Sep 19, 1995 |
| Priority date | — |
| Expiry date | May 16, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F1/304
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A high-power radio-frequency amplifier act on periodic pulses of RF energy. The bias is controlled for each of a bank of FETs or other amplifier devices that constitutes the main power stage. A sample of bias current is obtained during a blanking period on the front porch of the RF gating period. Quiescent drain current is measured, and stored on a sample/hold circuit. A digital signal processor provides bias values that are sent via a D/A converter to biasing circuits that add the bias levels to the input RF signal. If the bias current is above or below a desired level, the stored bias level is decreased or incremented respectively. A timing control circuit gates the sample/hold circuit and switches in advance of the biasing circuits. The timing control circuit also creates a blanking signal to apply to an attenuator to produce a null region during the first 100 microseconds of the gating signal. A thermal sensor is coupled to one or more amplifying devices for presetting the operating voltage when operation has been interrupted for a predetermined period of time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.