Abstract: An apparatus for sensing power amplifier current includes a system voltage source that is used to develop a reference voltage, a wire bond structure connected between the system voltage source and a power amplifier, where a sense voltage developed across the wire bond structure is indicative of a current flowing through the power amplifier, and a current source configured to compensate the reference voltage for changes in resistance of the wire bond structure due to a temperature coefficient of the wire bond structure.

Abstract: In a portable radio transceiver, a power amplifier system includes a saturation detector that detects power amplifier saturation in response to duty cycle of the amplifier transistor collector voltage waveform. The saturation detection output signal can be used by a power control circuit to back off or reduce the amplification level of the power amplifier to avoid power amplifier control loop saturation.

Abstract: An apparatus for sensing power amplifier current includes a system voltage source that is used to develop a reference voltage, a wire bond structure connected between the system voltage source and a power amplifier, where a sense voltage developed across the wire bond structure is indicative of a current flowing through the power amplifier, and a current source configured to compensate the reference voltage for changes in resistance of the wire bond structure due to a temperature coefficient of the wire bond structure.

Abstract: In a portable radio transceiver, a power amplifier system includes a saturation detector that detects power amplifier saturation in response to duty cycle of the amplifier transistor collector voltage waveform. The saturation detection output signal can be used by a power control circuit to back off or reduce the amplification level of the power amplifier to avoid power amplifier control loop saturation.

Abstract: A method and apparatus for biasing an amplifying device whereby the bias current tracks the input power or the power level of a control signal to thereby efficiently match the bias current with needs of the amplifying device. This method and apparatus overcomes the drawbacks of the prior art by biasing, not for maximum output power, but for the power level of the input signal or the control signal. In one embodiment a current conditioner operates in connection with the self adjusting biasing circuit to scale or adjust, potentially on an exponential basis, the biasing current for one or more amplifier stages. A cancellation current source may be configured within the bias circuit to cancel unneeded current to further minimize current consumption.

Abstract: An exemplary coupler detector circuit comprises a coupler, a detector circuit, and a harmonic tank. The coupler has a transmission line electromagnetically coupled to a coupled line, and the coupled line has an isolated node and a coupled node. The transmission line may, for example, be a 50 ohm RF line for transmitting RF energy. The detector circuit is connected to the coupled node and is configured to detect a power transmitted along the transmission line. The harmonic tank is connected to the coupled node, and is configured to short to ground at least one harmonic signal transmitted along the coupled node.

Abstract: According to an exemplary embodiment, a circuit arrangement includes a multi-mode bias circuit having a control voltage input, a mode control input for selecting between a linear mode and a saturation mode, and a bias output. The circuit arrangement further includes an amplifier having a bias input connected to the bias output of the multi-mode bias circuit, the amplifier having an RF input and an RF output. The multi-mode bias circuit causes the amplifier RF output power to be proportional to the RF input power when the mode control input selects the linear mode. Conversely, the multi-mode bias circuit causes the amplifier RF output power to be determined by the voltage at the control voltage input when the mode control input selects the saturation mode.

Abstract: An exemplary coupler detector circuit comprises a coupler, a detector circuit, and a harmonic tank. The coupler has a transmission line electromagnetically coupled to a coupled line, and the coupled line has an isolated node and a coupled node. The transmission line may, for example, be a 50 ohm RF line for transmitting RF energy. The detector circuit is connected to the coupled node and is configured to detect a power transmitted along the transmission line. The harmonic tank is connected to the coupled node, and is configured to short to ground at least one harmonic signal transmitted along the coupled node.

Abstract: The invention includes an amplifier and a biasing circuit. The amplifier may have one or more driver stages and a final stage. Each stage may be connected in series to pass along and amplify an input signal from one stage to the next. The input signal level may increase over time. The biasing circuit may include a voltage follower having an output and a reference transistor. Each stage may include a transistor having a base that is connected to the output of the voltage follower. A resistor may be placed between each transistor stage base and the output of the voltage follower. The base of the final stage transistor may be DC connected to the reference transistor base. In operation, the reference transistor collector current and thus the final stage base bias voltage may be maintained at fixed level by feedback through the voltage follower.