Abstract: Various implementations include circuits, devices and/or methods that provide open loop current limiting power amplifiers and the like. In some implementations, an open loop current clamp includes a trim module to provide a control value and a limiting source having respective input and output terminals. The input terminal is coupled to the trim module to receive the control value. The output terminal coupled to a control terminal of the first transistor to provide a limiting electrical level produced in response to the control value by the limiting source. The limiting electrical level substantially setting a first mode of operation for the first transistor such that the current draw of the first transistor is substantially determined by the first mode of operation and the limiting electrical level such that a voltage at an output terminal of the first transistor exerts reduced influence on the current draw.

Abstract: A system for power amplifier control saturation detection and correction includes a comparator configured to receive a power control signal and a detected power signal and generate a regulated voltage, a power amplifier configured to receive the regulated voltage and develop an output power, a power detector configured to sense the output power and develop the detected power signal, a saturation detector configured to receive the regulated voltage and a system voltage and determine whether the power amplifier is operating in a saturation mode during a transmit burst, and a current generator configured to reduce the power control signal when the power control signal exceeds a predetermined value and after expiration of a predetermined period of time, preventing the power control signal from exceeding the detected power signal.

Abstract: A power correction module for use with an amplifier driving a load impedance is configured to sample the supply current and to cause a change in a control voltage, which corrects the supply voltage in response to a change in the load impedance. The supply voltage is corrected to cause the power amplifier to have a substantially constant output power. The power correction module is further configured to output a corrected peak voltage determined by an average value of the supply current.

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: 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: A system for power amplifier control saturation detection and correction includes a comparator configured to receive a power control signal and a detected power signal and generate a regulated voltage, a power amplifier configured to receive the regulated voltage and develop an output power, a power detector configured to sense the output power and develop the detected power signal, a saturation detector configured to receive the regulated voltage and a system voltage and determine whether the power amplifier is operating in a saturation mode during a transmit burst, and a current generator configured to reduce the power control signal when the power control signal exceeds a predetermined value and after expiration of a predetermined period of time, preventing the power control signal from exceeding the detected power signal.

Abstract: According to an exemplary embodiment, a transmitter system includes a power amplifier receiving a supply voltage and a supply current from a power control/current detection circuit, where the power amplifier drives a load impedance. The transmitter system further includes a power correction module configured to sample the supply current and to cause a change in a control voltage, which corrects the supply voltage in response to a change in the load impedance. The supply voltage is corrected to cause the power amplifier to have a substantially constant output power. The power correction module is further configured to output a corrected peak voltage determined by an average value of the supply current. The transmitter system further includes a predistortion module configured to determine the control voltage from a product of the corrected peak voltage and an amplitude modulation component and to output the control voltage to the power control/current detection circuit.

Abstract: A power correction module for use with an amplifier driving a load impedance is configured to sample the supply current and to cause a change in a control voltage, which corrects the supply voltage in response to a change in the load impedance. The supply voltage is corrected to cause the power amplifier to have a substantially constant output power. The power correction module is further configured to output a corrected peak voltage determined by an average value of the supply current.

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: According to an exemplary embodiment, an amplification module includes a power amplifier configured to receive an RF input signal and provide an RF output signal. The amplification module further includes an autobias control circuit configured to receive and convert the RF output signal to a control signal. The control signal can cause the power amplifier to have a quiescent current that increases substantially linearly in response to an increase in the RF output power of the RF output signal. The autobias control circuit can include a peak detector/log converter circuit coupled to a first input of a differential amplifier, where the differential amplifier outputs the control signal. The autobias control circuit can further include a DC reference circuit coupled to a second input of the differential amplifier. The amplification module further includes an analog bias circuit coupling the control voltage to a bias input of said power amplifier.

Abstract: According to an exemplary embodiment, a transmitter system includes a power amplifier receiving a supply voltage and a supply current from a power control/current detection circuit, where the power amplifier drives a load impedance. The transmitter system further includes a power correction module configured to sample the supply current and to cause a change in a control voltage, which corrects the supply voltage in response to a change in the load impedance. The supply voltage is corrected to cause the power amplifier to have a substantially constant output power. The power correction module is further configured to output a corrected peak voltage determined by an average value of the supply current. The transmitter system further includes a predistortion module configured to determine the control voltage from a product of the corrected peak voltage and an amplitude modulation component and to output the control voltage to the power control/current detection circuit.

Abstract: According to an exemplary embodiment, an amplification module includes a power amplifier configured to receive an RF input signal and provide an RF output signal. The amplification module further includes an autobias control circuit configured to receive and convert the RF output signal to a control signal. The control signal can cause the power amplifier to have a quiescent current that increases substantially linearly in response to an increase in the RF output power of the RF output signal. The autobias control circuit can include a peak detector/log converter circuit coupled to a first input of a differential amplifier, where the differential amplifier outputs the control signal. The autobias control circuit can further include a DC reference circuit coupled to a second input of the differential amplifier. The amplification module further includes an analog bias circuit coupling the control voltage to a bias input of said power amplifier.

Abstract: The invention provides a system that enables a power amplifier to operate in a compressed mode and then be switched during operations to operate in a linear mode. Broadly conceptualized, the system may include a power amplifier and a bias controller that efficiently permits a communication device to function with either the compressed waveforms of a first air interface system or linear waveforms from other air interface systems.

Abstract: The invention includes an integrated circuit chip having a closed loop control module. The closed loop control module includes a power amplifier coupled to a feedback control circuit. The power amplifier linearly amplifies a communication signal based on a modified control signal received from the feedback circuit. To produce the modified control signal, the feedback circuit may receive from the power amplifier a passive representation of the power amplifier collector current or an active representation of the power amplifier collector current. The feedback control circuit takes the collector current representative signal received from the power amplifier and compares to a voltage control signal. The comparison results in a signal that is passed through a loop integrator to create the modified control signal use to control the amplification of the communication signal in the power amplifier. A feedback saturation detecting circuit may be fixed about the loop integrator to prevent saturation.

Abstract: The invention provides a system that enables a power amplifier to operate in a compressed mode and then be switched during operations to operate in a linear mode. Broadly conceptualized, the system may include a power amplifier and a bias controller that efficiently permits a communication device to function with either the compressed waveforms of a first air interface system or linear waveforms from other air interface systems.

Abstract: An intermediate frequency amplifier for wireless communication applications has the same receive path and transmit path through an off-chip filter. The intermediate frequency amplifier circuit includes a first amplifier and a second amplifier. The second amplifier includes a gain control circuitry. The second amplifier provides gain control for both the receive mode and for the transmit mode of operation. The IF amplifier can be used in a variety of communication applications, including cordless telephones, cellular phones, PHS phones, wireless modems, radios, and other devices.

Abstract: A frequency conversion or synthesis circuit including a double balance differential active ring mixer with a current shared active radio frequency (RF) input balun, suitable for use in an RF receiver. The circuit is configured to be coupled to a bias circuit for providing a relatively constant current and a buffer circuit for receiving a signal from a local oscillator (LO) source and generating differential LO signals.