Abstract: Systems and methods are described for a power amplifier with a tracking power supply. The power amplifier may use envelope tracking. The power amplifier is protected when the output of the power amplifier is short circuited or overloaded.

Abstract: Disclosed herein are apparatuses and methods for configuring a circuit board to have a plurality of die having different bottom-side electrical potential. An apparatus comprises a circuit board comprising a metallic base plate, a thermally conductive dielectric, and a plurality of metallic pads. Each of a plurality of die of the apparatus is coupled to a respective one of the plurality of metallic pads, and the plurality of die comprises a first die and a second die. Based on each of the plurality of die being coupled to a respective one of the plurality of metallic foil pads, the first die is configured to exhibit a first bottom-side electrical potential and the second die is configured to exhibit a second bottom-side electrical potential. The apparatus is further configured to conduct heat from the plurality of die away from the plurality of die via at least the metallic base plate, the thermally conductive dielectric, and the plurality of metallic pads.

Abstract: A selectable current limiter circuit to limit the current an amplifier with a load. The limiter circuit limits the current of an amplifier by comparing a voltage reference that follows the output swing of the amplifier to voltage drop across a current limiting resistor coupled to the output of the amplifier. The limiter circuits are operatively coupled to buffer and switch circuits that delay the current limiting until the limiter circuits are activated.

Abstract: A multiplexed multilevel converter amplifier. The converter is configured to generate a converter voltage. The converter voltage varies among a plurality of voltage levels. A multiplexer is comprised of at least four switches configured to generate a positive output voltage and a negative output voltage according to a configuration of the at least four switches. The positive output voltage varies between the converter voltage and a positive supply rail and the negative output voltage varies between the converter voltage and a negative supply rail. An amplifier is supplied by the multiplexer, and the amplifier generates an output voltage that varies between the positive output voltage and the negative output voltage. A control module is configured to control the configuration of the at least four switches of the multiplexer and the plurality of voltage levels of the converter voltage, such that the converter voltage is synchronized with the output voltage.