Adaptive bias current circuit and method for amplifiers
AssigneeThe Regents of the University of California
InventorsVincent W. Leung, Prasad S. Gudem, Lawrence E. Larsen
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Abstract
An adaptive bias method and circuits for amplifiers that provide a substantial current boost based at least partly upon a sensed input power of an amplifier circuit. Methods and circuits of the invention provide an additional bias current based upon the sensed input power. Circuits of the invention may be simple, area-efficient, low-power, stable and digitally-programmable. In addition, methods and circuits of the invention may be used with a number of amplifier circuit configurations, including amplifiers having either inductor and/or resistive degeneration.
Claims22
A method for producing an adaptive bias current responsive to an input power of an RF amplifier, the method comprising steps of:
- accepting negative and positive input voltages of the RF amplifier;
- producing a differential current responsive to the negative and positive input voltages of the RF amplifier, wherein the differential current clips within the normal operational range of the RF amplifier;
- and
- filtering at least one harmonic from the differential current.
An adaptive bias current circuit for producing a bias current responsive to the input power of an RF amplifier, the bias current circuit comprising:
- current supply means for supplying a quiescent current;
- and
- differential power sensor means, biased by the quiescent current, for sensing the input power of the RE amplifier and for producing a bias current higher than the quiescent current when the input power reaches a high level, the bias current being responsive to the input power.
An adaptive bias current circuit for producing a bias current responsive to the input power of an RF amplifier, the bias current circuit comprising:
- a quiescent current bias supply circuit generating a quiescent current;
- a differential transistor pair biased by the quiescent current, the differential transistor pair including a first transistor generating a first collector current responsive to a positive voltage phase of the input power of the RF amplifier and a second transistor generating a second collector current responsive to a negative voltage phase of the input power of the RF amplifier, the quiescent current set to permit the first and second collector currents to clip when the input power of the RF amplifier reaches a predetermined level;
- and
- a current summer for summing the first and second collector currents to produce the bias current.
An adaptive bias current circuit comprising:
- a current supply configured to supply a quiescent current;
- and
- a differential power sensor configured to be biased by at least the quiescent current and to determine an input power of the RF amplifier and to generate a bias current larger than the quiescent current when the input power reaches a predetermined high level, the bias current being roughly proportional to the input power.
Dependencies are inferred from the claim text.