Title:
INGRATED RF POWER SENSOR THAT COMPENSATES FOR BIAS CHANGES
Document Type and Number:
WIPO Patent Application WO2001056176
Kind Code:
A3
Abstract:
A system for controlling a bias circuit by sensing RF amplifier output power and compensating for a dominating quiescent bias current includes an amplifier transistor and two sampling transistors. The two sampling transistors are physically smaller than the amplifier transistor, and are preferably the same size. The first sampling transistor is configured to sample the same RF input signal that is amplified by the amplifier transistor. The second sampling transistor is configured to receive and amplify only a bias network signal. The bias network associated with the transistors includes a selection of components based upon operating parameters as well as actual physical sizes of the transistors. The selection of component values in association with transistor sizes is used to enable generation of a current sensing signal that is proportional to the power level of the RF output signal generated by the amplifier transistor. The bias current to the amplifier transistor is controlled by an operational amplifier that is fed with a reference voltage and the dc bias detected by the second small transistor.
Inventors:
DENING DAVID C
AUGUSTINE PAUL J
AUGUSTINE PAUL J
Application Number:
PCT/US2001/000613
Publication Date:
December 13, 2001
Filing Date:
January 09, 2001
Export Citation:
Assignee:
RF MICRO DEVICES INC (US)
International Classes:
H03F1/02; (IPC1-7): H03G3/30
Foreign References:
| US6137354A | 2000-10-24 | |||
| US5497125A | 1996-03-05 |
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