Apparatus and methods for capacitive load reduction are disclosed. In one embodiment, a power amplifier system includes an envelope tracker configured to provide a supply voltage to a plurality of power amplifiers. The power amplifiers include power supply inputs electrically connected in a star configuration so as to reduce a capacitive load of the envelope tracker. The distributed capacitance of the power amplifiers is used to provide RF grounding so as to reduce the size of or eliminated the use of bypass capacitors.

Apparatus and methods for capacitive load reduction

Optimization methods via various circuital arrangements for amplifier with variable supply power are presented. In one embodiment, a switch can be controlled to include or exclude a feedback network in a feedback path to the amplifier to adjust a response of the amplifier dependent on a region of operation of the amplifier arrangement (e.g. linear region or compression region).

Optimization methods for amplifier with variable supply power

Various methods and circuital arrangements for biasing one or more gates of stacked transistors of an amplifier are presented, where the amplifier can be an envelope tracking amplifier. Circuital arrangements to generate reference gate-to-source voltages for biasing of the gates of the transistors of the stack are also presented. Particular biasing for a case of an input transistor of the stack is also presented.

Bias Control for Stacked Transistor Configuration

Various envelope tracking amplifiers are presented that can be switched between an ET (envelope tracking) mode and a non-ET mode. Switches and/or tunable components are utilized in constructing the envelope tracking amplifiers that can be switched between the ET mode and the non-ET mode.

Amplifiers Operating in Envelope Tracking Mode or Non-Envelope Tracking Mode

A space-based solar power station, a power generating satellite module and/or a method for collecting solar radiation and transmitting power generated using electrical current produced therefrom, and/or compactible structures and deployment mechanisms used to form and deploy such satellite modules and power generation tiles associated therewith are provided. Each satellite module and/or power generation tile may be formed of a compactable structure and deployment mechanism capable of reducing the payload area required to deliver the satellite module to an orbital formation within the space-based solar power station and reliably deploy it once in orbit.

Large-Area Structures for Compact Packaging

A power amplifier using a drain (collector) power control loop in which the feedback signal is an estimated output power level computed with a linear summation of the output sensed voltage and current. Both RF and baseband voltage and current sensing are possible, and voltage-mode or current-mode signal processing are feasible. This control loop technique is applicable to any means of drain power control circuits such as: supply regulators, DC-DC converters and others. Voltage error amplifiers can be used in conjunction with voltage feedback network, while current error amplifiers can be used with current feedback networks. Regulator sharing between different bands may be used as an area and cost reduction solution. The linear voltage and current summation driven power control technique can be also applied to the gate (base) power control scheme. Similarly, voltage-mode and current-mode signal processing can be implemented.

Power amplifier with power feedback

A power amplifier system is provided with a signal path including driver stages and output stages. A power control element has one or more control ports and uses one or more nonlinear control characteristics.

Stephen Franck

Papers

Power amplifier with power feedback

Power amplifier with back-off efficiency