Abstract: A method of controlling output power in a power amplifier having a driver stage and an output stage. The driver current is measured and the output stage biased in dependence upon the measured driver current.

Abstract: Multiple circuits connected to a common terminal are switched where the frequency bands to be conducted through the circuits are close. Each circuit has an independent signal path to the common terminal which contains a filter and a device. Each device has a first and a second state. Each circuit has a first filter characteristic that passes a first frequency band and substantially blocks the second frequency band. Each circuit has a second filter characteristic which substantially blocks the first and second frequency bands when the device is in the second state, wherein the second filter characteristic is a result of the device and a filter acting in combination. As a result, the frequency multiplexer can have multiple frequency bands in a narrow frequency range connected to a common terminal with minimum signal loss.

Abstract: RF polar modulation circuit has a self-compensated temperature stable envelope controller and self-compensated temperature stable power amplifier bias. The circuit has an adaptive current-to-voltage modulation interface with pre-distortion compensation capability. AM/PM distortion are compensated for envelope dependent power amplifier transistor biasing. Automatic compensation is provided for RF loads that are higher or lower than nominal loads. This Abstract is provided to comply with rules requiring an Abstract that allows a searcher or other reader to quickly ascertain subject matter of the technical disclosure. This Abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: The present invention provides a transceiver circuit that includes a transmission amplifier coupled with an antenna input/output node. The transmission amplifier is configured to amplify communications to be transmitted from the transceiver circuit. The transceiver circuit further includes a receiver and a field effect transistor. The receiver includes a receiver input coupled with the antenna input/output node. The field effect transistor is coupled between the receiver input and an electrical reference. The field effect transistor is configured to provide an open circuit when communications are received at the receiver input and to provide a closed circuit when communications are not being received at the receiver input.

Abstract: A hybrid coupler (66, 67; 72, 73) has four ports and is capable of coupling radio frequency signals having a certain frequency from at least one port to at least one other port. The hybrid coupler (66, 67; 72, 73) is implemented as a differential coupler arranged to couple differential radio frequency signals. With such a hybrid coupler a power amplifying circuit can be produced which has sufficiently low ripple on the supply voltage to be integrated together with more sensitive radio circuits, and which is also insensitive to load mismatch such that an isolator can be avoided. A differential hybrid coupler allows the output current to be shared between four transistors or amplifiers, thus reducing the amplitude of the ripple. Further, the frequency of the ripple is four times the operating frequency of the circuit, which makes it much easier to filter out the ripple.

Abstract: A level shifting circuit for level shifting a control signal which sets a Gate voltage of a power amplifier includes circuitry for adding gain to the level shift. The addition of gain to the level shift causes the gate voltage to change faster than the control voltage, and this, in turn, makes it possible to get higher dynamics to control the Gate voltage of the power amplifier. When the circuitry is utilized in a power amplifier including a plurality of amplifier stages, problems associated with the output stage showing non-monotonic behavior can be avoided. The level shifting circuit is particularly useful in power amplifiers using MESFET transistors such as power amplifiers used in cellular telephones.

Abstract: A power amplifier that operates at a high efficiency over a wide power range. In one embodiment, the power amplifier includes a first circuit having a first transistor including an input terminal for receiving an RF input, a first output terminal connected to ground, and a second output terminal connected to a first inductor connected in series with a capacitor and also connected to a voltage supply through a first controllable connector; a second circuit including a second transistor having an input terminal for receiving the radio frequency (RF) input, a first output terminal connected to ground, and a second output terminal connected to a second inductor connected in series with the capacitor and also connected to a voltage supply through a second controllable connector; and bias means for biasing the first transistor and the second transistor, wherein the first circuit is connected in parallel to the second circuit.

Abstract: A DC/DC converter circuit includes an input capacitor, an inductor, a diode, a transistor, and a control circuit. The control circuit operates to control the transistor. An output capacitor is connected between the output and the input of the circuit. Connection in this way reduces the amount of energy passing through the output capacitor, which usefully reduces the size of the output capacitor.

Abstract: A circuit for regulating the power provided to a load connected to an output of a power amplifier. The circuit using a control current, rather than a control voltage, to bias the power amplifier.

Abstract: A level shifting circuit for level shifting a control signal which sets a Gate voltage of a power amplifier includes circuitry for adding gain to the level shift. The addition of gain to the level shift causes the gate voltage to change faster than the control voltage, and this, in turn, makes it possible to get higher dynamics to control the Gate voltage of the power amplifier. When the circuitry is utilized in a power amplifier including a plurality of amplifier stages, problems associated with the output stage showing non-monotonic behavior can be avoided. The level shifting circuit is particularly useful in power amplifiers using MESFET transistors such as power amplifiers used in cellular telephones.

Abstract: A circuit for regulating the power provided to a load connected to an output of a power amplifier. The circuit using a control current, rather than a control voltage, to bias the power amplifier.

Abstract: A circuit for regulating the power provided to a load connected to an output of a power amplifier. The circuit includes an amplitude detector that outputs a voltage corresponding to the amplitude of the signal outputted by the power amplifier. This output voltage is a function of the impedance of the load. Thus, when the impedance of the load changes, the output voltage also changes. Given a constant current into the load, it is the load impedance that determines the power delivered to the load. Therefore, because the output voltage reflects changes in the impedance of the load, the output voltage can be used by a regulator circuit to maintain a constant output power, regardless of changes in the impedance of the load.

Abstract: A power amplifier system and a method for controlling a power amplifier in a power amplifier system. The method controls the power amplifier in a power amplifier system which has a loop by which a parameter proportional to the output power of the power amplifier is sensed and fed back to an error amplifier, and the output of the error amplifier is fed to a control input of the power amplifier as a control signal. The method adds an extra gain to the loop. By adding the extra gain, the loop will always be in an active condition, even at very low output power levels and at high power levels so as to provide for a more robust power regulation.

Abstract: Apparatus for adjusting the height of a vehicle frame on a vehicle is disclosed including a pneumatic suspension system for adjusting the elevation of the vehicle frame, and a controller for controlling the pneumatic suspension system, the controller being adapted to be set in a first mode corresponding to normal driving of the vehicle and a second mode corresponding to parking or marshalling of the vehicle, whereby when the controller is in the first mode, the pneumatic suspension system permits adjustment of the vehicle frame within a first range and when the controller is in the second mode the pneumatic suspension system permits adjustment of the vehicle frame within the second range, the first range being greater than the second range, and the second range being within the first range.

Abstract: A power amplifier that operates at a high efficiency over a wide power range. In one embodiment, the power amplifier includes a first circuit having a first transistor including an input terminal for receiving an RF input, a first output terminal connected to ground, and a second output terminal connected to a first inductor connected in series with a capacitor and also connected to a voltage supply through a first controllable connector; a second circuit including a second transistor having an input terminal for receiving the radio frequency (RF) input, a first output terminal connected to ground, and a second output terminal connected to a second inductor connected in series with the capacitor and also connected to a voltage supply through a second controllable connector; and bias means for biasing the first transistor and the second transistor, wherein the first circuit is connected in parallel to the second circuit.

Abstract: A circuit for controlling the characteristics of a power amplifier including first and second inputs, a first amplitude detection circuit for producing a first output signal indicative of the amplitude of an input signal received from the first input, and a second amplitude detection circuit for producing a second output signal indicative of the amplitude of an input signal received from the second input. The circuit also includes a phase detection circuit for producing a phase signal indicative of the relative phase between the input signals supplied to the first and second inputs, an amplitude control circuit for receiving the outputs of the first and second amplitude detection circuits and producing an amplitude control signal therefrom, and a phase control circuit for receiving the output of the phase detection circuit and producing a phase control signal therefrom.

Abstract: A hybrid coupler (66, 67; 72, 73) has four ports and is capable of coupling radio frequency signals having a certain frequency from at least one port to at least one other port. The hybrid coupler (66, 67; 72, 73) is implemented as a differential coupler arranged to couple differential radio frequency signals. With such a hybrid coupler a power amplifying circuit can be produced which has sufficiently low ripple on the supply voltage to be integrated together with more sensitive radio circuits, and which is also insensitive to load mismatch such that an isolator can be avoided. A differential hybrid coupler allows the output current to be shared between four transistors or amplifiers, thus reducing the amplitude of the ripple. Further, the frequency of the ripple is four times the operating frequency of the circuit, which makes it much easier to filter out the ripple.

Abstract: An antenna switch includes at least one signal path, including an amplifier device and a switch. The amplifier device includes an amplifier connected to a first inductor and to a first capacitor, which is grounded. The amplifier is voltage supplied via a second inductor. The switch includes a receiving isolation device, which is connected to a bypass capacitor connected to an antenna via a low pass filter. A first microstrip is connected to the bypass capacitor and to a DC switch. The first inductor and the first capacitor together with a shorted output transistor of the amplifier form a high impedance in receiving mode, thereby not affecting the receiving signal. The receiving isolation device is a signal wire.

Abstract: A DC/DC converter circuit includes an input capacitor (C11), an indicator (L11), a diode (D11), a transistor (T11) and a control circuit (18). The control circuit operates to control the transistor (T11). An output capacitor (C21) is connected between the output and the input of the circuit. Connection in this way usefully reduces the size of the output capacitor.

Abstract: A field effect transistor circuit comprises a field effect transistor (1) having drain (D) and source (S) terminals for connection to respective power supply (Vss, 4) rails and a gate terminal (G) for receiving an input signal. The circuit further comprises a diode (6) which has its anode (B) connected to the gate terminal (G) of the transistor (1) and its cathode for connection to a bias voltage source (7), Vb). The diode (6) is arranged such that when the circuit is in use, the voltage level of the gate terminal (G) of the field effect transistor (1) is maintained at or below a predetermined value.