Rf Micro Devices, Inc.

Ryan Bosley

Michael F Zybura

Darrell G Epperson

Jackie Johnson

Carlos Gamero

Scott Yoder

Joel Robert Gibson

Michael S LaBelle

Frank Tamborino

A system and method are provided for maintaining a consistent operating condition of a power amplifier power amplifier across a range of operating temperatures. The power amplifier is provided with an input bias voltage (Vbias) that adjusts with temperature to compensate for the temperature dependent change of the power amplifier's base-emitter voltage drop Vbe. This maintains a consistent operating condition in the power amplifier, which reduces temperature-dependent changes in the amplifier's gain.

Temperature compensated bias for AM/PM improvement

Polar modulation input signals to a polar modulated power amplifier include a phase modulated (PM) input signal, which feeds a power amplifier input, and an amplitude modulated (AM) input signal, which provides an envelope supply voltage for the power amplifier. The present invention is a large signal polar modulated power amplifier that extends the effective amplitude range of AM input signals that can be handled by the power amplifier by amplitude modulating the PM input signal using the AM input signal. Amplitude modulating the PM input signal effectively lowers the amplitude of the PM input signal when the amplitude of the AM input signal is lowered, which maintains adequate headroom between the power amplifier's signal input and envelope supply voltage input in the presence of large amplitude AM input signals. As a result, the power amplifier can amplify larger amplitude AM input signals than traditional power amplifier designs.

Large signal polar modulated power amplifier

A power amplifier configuration including power amplifier circuitry and power control circuitry and having improved Power Added Efficiency (PAE) is provided. The power amplifier circuitry includes one or more input amplifier stages in series with a final amplifier stage. The power control circuitry provides a variable supply voltage to the input amplifier stages based on an adjustable power control signal. The final amplifier stage is powered by a fixed supply voltage. In operation, as output power of the power amplifier is reduced from its highest power level, the variable supply voltage is reduced. Accordingly, RF power of an amplified signal provided to the final amplifier stage from the input amplifier stages decreases, and the final amplifier stage transitions from saturation to linear operation, thereby increasing the gain of the final amplifier stage. Thus, a desired output level can be maintained while operating at lower current levels.

Power amplifier control technique for enhanced efficiency

A system is provided for substantially reducing variation in AM to PM distortion of a power amplifier caused by variations in RF drive power and temperature. The system includes power control circuitry and power amplifier circuitry. The power amplifier circuitry includes an input amplifier stage and at least one additional amplifier stage coupled in series with the input amplifier stage. The power control circuitry provides a first supply voltage to the input amplifier stage based on a control signal such that the first supply voltage has a predetermined DC offset with respect to the control signal. The first supply voltage is provided such that the predetermined DC offset substantially reduces variations in the AM to PM distortion of the power amplifier due to variations in radio frequency (RF) drive power.

Tailored collector voltage to minimize variation in AM to PM distortion in a power amplifier

The present invention provides temperature compensation for a power amplifier by varying a supply voltage applied to the power amplifier. The supply voltage is varied based on operating temperature in light of the temperature characteristics of the power amplifier. Thus, the variation in the supply voltage offsets variations in the characteristics of the power amplifier due to changes in temperature. Whether the power amplifier is used to control the output power of a transmitter or as part of a polar modulation system, temperature compensation of the power amplifier allows the power amplifier to provide an accurate and repeatable output signal having essentially no fluctuations due to changes in temperature.

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Greensboro, NC, United States of America

Ryan Bosley