Abstract: A system is provided for adjusting an output power of a multi-stage power amplifier by controlling a supply voltage provided to one or more output amplifier stages of the power amplifier using a switching DC—DC converter. In general, the system includes a power amplifier including an input amplifier stage and one or more output amplifier stages coupled in series with the input amplifier stage. The one or more output amplifier stages receive a variable supply voltage from switching DC—DC conversion circuitry. The switching DC—DC conversion circuitry provides the variable supply voltage based on an adjustable power control signal. By controlling the variable supply voltage provided to the one or more output stages, the switching DC—DC conversion circuitry controls an output power of the power amplifier based on the adjustable power control signal.

Abstract: The present invention eliminates the need for complex impedance networks or parallel amplification stages for multi-mode mobile terminals. A wideband power amplifier is configured to amplify signals in different frequency bands corresponding to different operating modes. The supply voltage of the wideband power amplifier is adjusted in light of the load impedance of radiating circuitry to achieve a desired output power for the respective operating modes.

Abstract: An amplifier provides two or more selectively enabled amplifier segments allowing a source signal to be amplified with a selectable output power. A bias circuit responsive to a bias control signal enables selectable combinations of one or more amplifier segments, thus allowing selection of a desired output power. Selecting a desired output signal power via the bias control signal corresponds to selecting an overall amplifier quiescent current that decreases with decreasing output signal power. Thus, the amplifier permits a controlling system, such as a mobile terminal (e.g., cellular telephone) to amplify a transmit signal with a selectable transmit signal output power and corresponding level of amplifier quiescent power consumption. Preferably, each segment comprises one or more transistor amplification stages which, when enabled by the bias circuit, are biased to permit maximum power linear amplification for the transmit signal.

Abstract: The present invention provides a dual mode amplifier capable of operating in a common (even) mode for one frequency band and a differential (odd) mode for a second frequency band. In the common mode, the amplifier provides two identical signals to a matching network, and in the differential mode, the amplifier provides two signals that are 180° out-of-phase from one another to the matching network. The matching network is configured to maintain the same input and output impedance regardless of whether the amplifier is operating in the common or differential mode. Furthermore, the matching network is preferably configured to terminate second harmonics for each frequency band without affecting the fundamental tone for the other bands, even if the bands are an octave apart. Since the matching network operates on two signals, either common or differential signals, a power combining network is typically required to combine the two signals into a single signal for transmission.

Abstract: The present invention eliminates the need for complex impedance networks or parallel amplification stages for multi-mode mobile terminals. A wideband power amplifier is configured to amplify signals in different frequency bands corresponding to different operating modes. The supply voltage of the wideband power amplifier is adjusted in light of the load impedance of radiating circuitry to achieve a desired output power for the respective operating modes.

Abstract: An amplifier provides two or more selectively enabled amplifier segments allowing a source signal to be amplified with a selectable output power. A bias circuit responsive to a bias control signal enables selectable combinations of one or more amplifier segments, thus allowing selection of a desired output power. Selecting a desired output signal power via the bias control signal corresponds to selecting an overall amplifier quiescent current that decreases with decreasing output signal power. Thus, the amplifier permits a controlling system, such as a mobile terminal (e.g., cellular telephone) to amplify a transmit signal with a selectable transmit signal output power and corresponding level of amplifier quiescent power consumption. The amplifier is particularly advantageous for inclusion in systems designed for digital communications requiring variable transmit power levels, such as the digital cellular standard IS-95.

Abstract: A high efficiency multiple power level power amplifier has a PIN diode network that selectively associates an impedance transformation network with an interstage impedance matching network to maintain desired gain and linearity characteristics for the power amplifier at different output power levels. The PIN diode network in the off mode (high power), has a high breakdown voltage and high series resistance thereby reducing distortion components. The PIN diode network in the on mode (low power), has a low series resistance thereby reducing insertion losses.

Abstract: An FET crossbar switch device is implemented by using a split gate electrode and a shared source and drain pad to implement source and drain electrodes on an integrated circuit substrate. First and second inputs to the device are associated with first and second transmission lines, each of which is directly connected to a first and second source electrode areas. Disposed between the source electrode areas are respective drain electrode sections, each of which is coupled to an associated output transmission line. The input and output transmission lines are fabricated directly on the integrated circuit substrate. Gate fingers or electrodes are directed between respective drain electrodes and adjacent source electrodes. By properly biasing the gate electrodes, one can direct the first input to the first output with the second input directed to the second output. In a second state the first input can be connected to the second output with the second input disconnected or connected to the first output.

Abstract: An active-type broadband power divider has a pair of distributed amplifiers which are coupled together by a distributed capacitive coupling to provide a predetermined phase shift between respective output signals thereof. The distributed amplifiers are in the form of a row of three-terminal transistors having their gates and drains connected to gate and drain lines. The gate and drain lines are artificial transmission lines. By distributing the capacitive coupling between the gate and/or drain lines, a constant 90 degree phase shift is obtained over the entire bandwidth of the artificial transmission lines. For a 180 degree phase shift, a third distributed amplifier is provided with distributed capacitive coupling between its gate or drain line and that of the second distributed amplifier.

Abstract: A feed-forward amplifier utilizes frequency dependent delay elements to cancel the effects of phase dispersion in the amplifier to amplify a broadband, high-frequency signal with low distortion.