Patent ID: 6265943
Filing Date: 2001-07-24
Classification: H03F

Abstract:
A system for sensing RF amplifier output power and controlling a bias circuit comprising:a RF amplifier transistor configured to receive and amplify a RF signal;a first sampling transistor configured to receive and amplify the RF signal wherein the first sampling transistor is physically smaller than the RF amplifier transistor such that the first sampling transistor is capable of producing a proportionally smaller amplified RF signal than that capable of being produced by the RF amplifier transistor for a RF input signal common to both the RF amplifier transistor and the first sampling transistor;a second sampling transistor configured to receive and amplify a bias circuit signal;a first current sensing circuit configured to receive a RF signal amplified by the first sampling transistor and generate a RF current proportional to a RF signal amplified by the RF amplifier transistor;a second current sensing circuit configured to receive a bias circuit signal amplified by the second sampling transistor and generate a bias network current; anda feedback configured to be responsive to the bias circuit current and generate the bias circuit signal.