Power amplifier input structure having a differential output
AssigneeBlack Sand Technologies, Inc.
InventorsAlan L. Westwick, Timothy J. Dupuis, Susanne A. Paul
Life of this patent
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Abstract
A method and apparatus provides an input structure for a power amplifier. In one example, the input structure has an input network and a predriver circuit to provide an input signal to the power amplifier. The input network includes a transformer for helping to maintain a constant input impedance. The predriver includes a limiting amplifier that provides isolation between the power amplifier and the RF input. A DC feedback circuit is used by the predriver that maintains the DC level of the inverters to a desired level.
Claims16
An RF power amplifier suitable for transmitting signals in an RF communication system comprising:
- a power amplifier having an input and an output;
- a preamplifier stage coupled to the input of the power amplifier, wherein the preamplifier stage further comprises a transformer and a limiting amplifier, and wherein the limiting amplifier further comprises a plurality of series coupled inverters.
A circuit for transforming a singled-ended signal to a differential signal for use by an RF power amplifier formed on an integrated circuit, the circuit comprising:
- an RF power amplifier formed on the integrated circuit;
- a transformer formed on the integrated circuit, the transformer having a primary side with first and second terminals, and a secondary side with first and second terminals coupled to the RF power amplifier;
- and
- a pre-driver circuit coupled between the transformer and the RF power amplifier, the pre-driver circuit further comprising a limiting amplifier having a string of inverters;
- wherein a single ended RF input signal is coupled to the first terminal of the primary side of the transformer, producing a differential RF signal at the first and second terminals of the secondary side of the transformer.
A method of amplifying signals suitable for transmission in an RF communication system, the method comprising:
- amplifying signals present at the input of a power amplifier;
- and
- coupling a transformer and a limiting amplifier between an RF input signal and the input of the power amplifier, wherein the limiting amplifier includes plurality of series coupled inverters.
Dependencies are inferred from the claim text.