A power amplifier circuit includes a current generator and a current mirror driver. The current generator has a first input connected to a first voltage supply and an output configured to generate a first current. The current generator includes a first transistor, a second transistor, a first resistor and a second resistor. The first transistor has an emitter connected to ground. The second transistor has a base connected to a base of the first transistor and an emitter connected to ground. The first resistor is connected between the first voltage supply and a collector of the first transistor. The second resistor is connected between the first voltage supply and a collector of the second transistor. The current mirror drive has a first input connected to the output of the current generator to receive the first current and an output configured to generate a second current.

A biased-transistor-module comprising: a module-input-terminal; a module-output-terminal; a reference-terminal; a module-supply-terminal configured to receive a supply voltage; a module-reference-voltage-terminal configured to receive a module reference voltage; a main-transistor having a main-control-terminal, a main-first-conduction-channel-terminal and a main-second-conduction-channel-terminal, wherein the main-first-conduction-channel-terminal is connected to the module-output-terminal, and the main-second-conduction-channel-terminal is connected to the reference-terminal, and the main-control-terminal is connected to an input-signal-node, wherein the input-signal-node is connected to the module-input-terminal; and a bias-circuit. The bias-circuit comprises: a first-bias-transistor; a first-bias-resistor; a second-bias-transistor; and a second-bias-resistor.

Provided is a bias circuit that supplies a first bias current or voltage to an amplifier that amplifies a radio frequency signal. The bias circuit includes: an FET that has a power supply voltage supplied to a drain thereof and that outputs the first bias current or voltage from a source thereof; a first bipolar transistor that has a collector thereof connected to a gate of the FET, that has a base thereof connected to the source of the FET, that has a common emitter and that has a constant current supplied to the collector thereof; and a first capacitor that has one end thereof connected to the collector of the first bipolar transistor and that suppresses variations in a collector voltage of the first bipolar transistor.

A compensation circuit includes a power amplifier, a current bias circuit, a power detection circuit and a current control circuit; the power detection circuit is configured to detect the voltage amplitude of the radio frequency input signal of the power amplifier and output a reference current when the voltage amplitude meets a preset condition; the current control circuit is configured to receive a reference current and output a compensation current to the current bias circuit based on the reference current; the current bias circuit is configured to receive the compensation current and generate the direct-current bias current, and output the compensation current and the direct-current bias current to the power amplifier; and the power amplifier is configured to receive the compensation current and the direct-current bias current, and amplify the power of the radio frequency input signal based on the compensation current and the direct-current bias current.

A bias circuit of a power amplifier includes a first part circuit, a second part circuit and a power supply, in which the power supply is connected with a power supply end of the first part circuit; two ends of the first part circuit are connected in parallel with two ends of the second part circuit, and after parallel connection one end of a parallel circuit is connected with a gate of the first transistor of the power amplifier in a signal amplification circuit; the first part circuit is configured to provide a first bias voltage, and the second part circuit is configured to provide a second bias voltage; the two bias voltages are superimposed to provide a stable bias voltage; and an impedance of the bias circuit is in a preset range of the impedance.

A power amplifier circuit includes an amplifier transistor having a base, a collector, a bias circuit, and a first resistance element connected between the base of the amplifier transistor and the bias circuit. The bias circuit includes a voltage generation circuit, a first transistor having a base to which a first direct-current voltage is supplied, and an emitter from which the bias current or voltage is supplied, a second transistor having a base to which a second direct-current voltage is supplied, and an emitter connected to the emitter of the first transistor, a signal supply circuit disposed between the base of the amplifier transistor and the base of the second transistor, and an impedance circuit disposed between the base of the first transistor and the base of the second transistor.

Provided is a power amplification module that includes: a first transistor, a first signal being inputted to a base thereof; a second transistor, the first signal being inputted to a base thereof and a collector thereof being connected to a collector of the first transistor; a first resistor, a first bias current being supplied to one end thereof and another end thereof being connected to the base of the first transistor; a second resistor, one end thereof being connected to the one end of the first resistor and another end thereof being connected to the base of the second transistor; and a third resistor, a second bias current being supplied to one end thereof and another end thereof being connected to the base of the second transistor.

Bias schemes for cascode power amplifiers are disclosed. In certain embodiments, a power amplifier system includes a cascode power amplifier powered by a first supply voltage and that amplifies a radio frequency input signal, and a bias circuit including a voltage regulator that generates a regulated voltage and is powered by the first supply voltage. The bias circuit further includes a bias voltage generation circuit that receives the regulated voltage and generates at least one cascode bias voltage for the cascode power amplifier, a switch that gates a second supply voltage to generate a gated supply voltage, a bias current generation circuit that controls a bias current of the cascode power amplifier and is powered by the gated supply voltage, and a gating circuit that controls the switch based on the regulated voltage and the second supply voltage.

A high-frequency (HF) driver circuit for an acousto-optical component includes an HF power amplifier connected to a voltage regulator for supply with a supply voltage and a bias voltage generator connected to an input of the HF power amplifier via a switch. The HF driver circuit can include a measurement device configured to measure a temperature of the HF power amplifier and a compensation device configured to control the bias voltage generator according to the temperature. The bias voltage generator is configured to provide a bias voltage to the HF power amplifier. By switching in the bias voltage, the HF power amplifier can be adjusted to a low quiescent current. By switching off the bias voltage, the HF power amplifier can be very rapidly and effectively blocked. As a result, very rapid switching-on and switching-off times, e.g., in a range of 10 to 50 ns, can be achieved.

A current control circuit controls a bias current that is supplied to an amplifier transistor that amplifies a radio-frequency signal and includes a node, a constant current source circuit that supplies a first current to the node, and a variable current source circuit that supplies a second current to the node, based on a result of comparison between a potential of the node and a reference potential. The node outputs a control current including the first current and the second current for controlling the bias current.