Various methods and circuital arrangements for biasing gates of stacked transistor amplifier that includes two series connected transistor stacks of different polarities are presented, where the amplifier is configured to operate according to different modes of operation. Such circuital arrangements operate in a closed loop with a feedback error voltage that is based on a sensed voltage at a common node of the two series connected transistor stacks. According to one aspect, gate biasing voltages to input transistors of each of the two series connected stacks are adjusted by respective current mirrors that are controlled based on the feedback error voltage. According to another aspect, other gate biasing voltages are generated by maintaining a fixed gate biasing voltage between any two consecutive gate basing voltages.

Various methods and circuital arrangements for biasing gates of stacked transistor amplifier that includes two series connected transistor stacks of different polarities are presented, where the amplifier is configured to operate according to different modes of operation. Such circuital arrangements operate in a closed loop with a feedback error voltage that is based on a sensed voltage at a common node of the two series connected transistor stacks. According to one aspect, gate biasing voltages to input transistors of each of the two series connected stacks are adjusted by respective current mirrors that are controlled based on the feedback error voltage. According to another aspect, other gate biasing voltages are generated by maintaining a fixed gate biasing voltage between any two consecutive gate basing voltages.

A method for increasing efficiency of a radio frequency (RF) amplifier employing laterally diffused metal oxide semiconductor (LDMOS) transistors coupled to an RF exciter including determining an emission mode of modulated RF input signals generated by the exciter, if the emission mode is of a type where the modulated RF input signals have a continuously varying envelope, biasing the LDMOS transistors in the RF amplifier for linear operation, and if the emission mode is of a type where the modulated RF input signals do not have a continuously varying envelope, biasing the LDMOS transistors in the RF amplifier with a fixed quiescent drain current and a fixed drain supply voltage for the LDMOS transistors selected to cause the LDMOS transistors to operate in compression.

A method for increasing efficiency of a radio frequency (RF) amplifier employing laterally diffused metal oxide semiconductor (LDMOS) transistors coupled to an RF exciter including determining an emission mode of modulated RF input signals generated by the exciter, if the emission mode is of a type where the modulated RF input signals have a continuously varying envelope, biasing the LDMOS transistors in the RF amplifier for linear operation, and if the emission mode is of a type where the modulated RF input signals do not have a continuously varying envelope, biasing the LDMOS transistors in the RF amplifier with a fixed quiescent drain current and a fixed drain supply voltage for the LDMOS transistors selected to cause the LDMOS transistors to operate in compression.

A millimeter wave power amplifier device has multiple millimeter wave power amplifier circuits. Each millimeter wave power amplifier circuit includes a transistor, a first serial connection resonation unit, a second serial connection resonation unit, multiple first frequency band adjustment units and multiple second frequency band adjustment units. The transistor has a first end connected with an input end, a second end connected with a grounding end and a third end connected with an output end. Each of the first and second frequency band adjustment units has a switch member and two storage members. The switch member and the storage members of the first and second frequency band adjustment units are serially connected. The millimeter wave power amplifier device can achieve multi-frequency band adjustable effect to lower the cost.

A system for split-frequency amplification, preferably including: one or more primary-band amplification stages, one or more secondary-band amplification stages, one or more band-splitting filters, and/or one or more signal couplers. An analog canceller including one or more split-frequency amplifiers. A mixer including one or more split-frequency amplifiers. A voltage-controlled oscillator including one or more split-frequency amplifiers. A method for split-frequency amplification, preferably including: receiving an input signal, separating the input signal into signal portions, and/or amplifying the signal portions, and optionally including combining the amplified signal portions and/or providing one or more output signals.

A radio frequency module includes a mounting board, a power amplifier, a plurality of transmission filters, a first switch, an output matching circuit, a low-noise amplifier, and an external-connection terminal. The mounting board includes a first principal surface and a second principal surface on opposite sides of the mounting board. The first switch switches a connection between the power amplifier and the transmission filters. The output matching circuit is connected between the power amplifier and the first switch. The low-noise amplifier is disposed on the second principal surface of the mounting board. The external-connection terminal is disposed on the second principal surface of the mounting board. The power amplifier, the output matching circuit, the first switch, and the transmission filters are disposed on the mounting board in stated order in a direction that is orthogonal to a thickness direction of the mounting board.

A radio frequency module includes a mounting board, a power amplifier, a plurality of transmission filters, a first switch, an output matching circuit, a low-noise amplifier, and an external-connection terminal. The mounting board includes a first principal surface and a second principal surface on opposite sides of the mounting board. The first switch switches a connection between the power amplifier and the transmission filters. The output matching circuit is connected between the power amplifier and the first switch. The low-noise amplifier is disposed on the second principal surface of the mounting board. The external-connection terminal is disposed on the second principal surface of the mounting board. The power amplifier, the output matching circuit, the first switch, and the transmission filters are disposed on the mounting board in stated order in a direction that is orthogonal to a thickness direction of the mounting board.

Various methods and circuital arrangements for complete turn OFF of branches of a multi-branch cascode amplifier are presented. According to one aspect, a protection circuit coupled to a source node of an output transistor of a branch couples a reference voltage to the source node of the output transistor when the branch is turned OFF, and decouples the reference voltage from the source node when the branch is turned ON. According to another aspect, the protection circuit includes a switch whose off capacitance is sufficiently low so as not to affect performance of the branch when the branch is ON, and whose on resistance is sufficiently low to sufficiently reduce an RF amplitude at the source node of the output transistor when the branch is OFF and other branches are ON, and therefore allow use of low-voltage thin-oxide transistors in the branch. Further aspects include a second switch and use of transistor switches.

A method for unbalancing a tri-level switching regulator uses hysteretic control when switching across multiple states of the tri-level switching regulator. The method includes determining a battery voltage and an output voltage of the tri-level switching regulator. The method also includes dynamically adjusting at least one of a first hysteretic window of a first hysteretic comparator associated with a second switching state of the tri-level switching regulator and a second hysteretic window of a second hysteretic comparator associated with a first switching state of the tri-level switching regulator based on the battery voltage and the output voltage.