Abstract: A protection circuit is provided. The protection circuit protects a power amplifier that includes a power transistor configured to receive a power voltage, and a bias circuit configured to supply a bias current to the power transistor. The protection circuit includes: a first transistor, connected between a terminal of the bias circuit and a ground, and configured to sink a first current from the terminal of the bias circuit; and a second transistor, comprising a first terminal connected to the power voltage, a second terminal connected to a control terminal of the first transistor, and a control terminal connected to a reference voltage.

Abstract: A protection circuit is provided. The protection circuit protects a power amplifier that includes a power transistor configured to receive a power voltage, and a bias circuit configured to supply a bias current to the power transistor. The protection circuit includes: a first transistor, connected between a terminal of the bias circuit and a ground, and configured to sink a first current from the terminal of the bias circuit; and a second transistor, comprising a first terminal connected to the power voltage, a second terminal connected to a control terminal of the first transistor, and a control terminal connected to a reference voltage.

Abstract: A low noise amplifier includes: an amplification unit including a first transistor and a second transistor connected in a cascade structure and configured to amplify a signal input to a control terminal of the first transistor; and a gain controller connected between a contact point at which the first transistor and the second transistor are connected to each other and a power source voltage, and configured to adjust a gain of the amplification unit.

Abstract: A power amplifier includes a common source amplifier and a common gate amplifier circuit. The common source amplifier circuit has a terminal connected to a radio frequency (RF) input terminal and uses a source terminal commonly as an input terminal and an output terminal of the power amplifier. The common gate amplifier circuit has a terminal connected to the common source amplifier circuit and another terminal connected to an RF output terminal, and uses a gate terminal commonly as the input terminal and the output terminal of the power amplifier. The common gate amplifier circuit includes a Doherty amplifier including a main power amplifier and an auxiliary power amplifier that is connected to the main power amplifier in parallel.

Abstract: A power amplifier according to examples includes an amplifying circuit configured to amplify an input signal, a feedback circuit configured to feedback the amplified signal to the amplifying unit, and a feedback controlling circuit configured to control a power of the fed-back signal based on a power of the input signal. The feedback controlling unit performs controlling so that the power of the fed-back signal is increased as the power of the input signal is increased.

Abstract: A power amplifier include an amplifier including at least one field effect transistor (FET) that operates in an amplifying stage configured to amplify an input signal, and a body controller configured to control a bias voltage of a body terminal of the FET based on a power of the input signal. The body controller performs controlling so that the bias voltage of the body terminal is reduced in response to the power of the input signal being increased. Accordingly, such a power amplifier exhibits improved linearity.

Abstract: A power amplifier apparatus may include an amplifier configured to amplify an input signal and a delay transferring circuit connected between an input terminal and an output terminal of the amplifier, the delay transferring circuit configured to delay the input signal to transfer the delayed input signal to the output terminal of the amplifier.

Abstract: A power amplifier includes a common source amplifier and a common gate amplifier circuit. The common source amplifier circuit has a terminal connected to a radio frequency (RF) input terminal and uses a source terminal commonly as an input terminal and an output terminal of the power amplifier. The common gate amplifier circuit has a terminal connected to the common source amplifier circuit and another terminal connected to an RF output terminal, and uses a gate terminal commonly as the input terminal and the output terminal of the power amplifier. The common gate amplifier circuit includes a Doherty amplifier including a main power amplifier and an auxiliary power amplifier that is connected to the main power amplifier in parallel.

Abstract: A power amplifier according to examples includes an amplifying circuit configured to amplify an input signal, a feedback circuit configured to feedback the amplified signal to the amplifying unit, and a feedback controlling circuit configured to control a power of the fed-back signal based on a power of the input signal. The feedback controlling unit performs controlling so that the power of the fed-back signal is increased as the power of the input signal is increased.

Abstract: A power amplifier include an amplifier including at least one field effect transistor (FET) that operates in an amplifying stage configured to amplify an input signal, and a body controller configured to control a bias voltage of a body terminal of the FET based on a power of the input signal. The body controller performs controlling so that the bias voltage of the body terminal is reduced in response to the power of the input signal being increased. Accordingly, such a power amplifier exhibits improved linearity.

Abstract: A power amplifier apparatus may include an amplifier configured to amplify an input signal and a delay transferring circuit connected between an input terminal and an output terminal of the amplifier, the delay transferring circuit configured to delay the input signal to transfer the delayed input signal to the output terminal of the amplifier.

Abstract: A bias circuit may include an envelope detecting unit detecting an envelope of an input signal, a source voltage generating unit generating a source voltage using a power supply voltage, and an envelope amplifying unit receiving the power supply voltage and the source voltage as a driving voltage and amplifying an envelope signal detected by the envelope detecting unit to generate a first bias voltage.

Abstract: A bias circuit may include an envelope detecting unit detecting an envelope of an input signal, a source voltage generating unit generating a source voltage using a power supply voltage, and an envelope amplifying unit receiving the power supply voltage and the source voltage as a driving voltage and amplifying an envelope signal detected by the envelope detecting unit to generate a first bias voltage.

Abstract: A gate bias control circuit may includes a signal input unit connected to an input terminal of a power amplifier to receive an input signal from the power amplifier, a rectifying unit rectifying the input signal when the input signal has a voltage higher than a preset reference voltage, and a voltage regulating unit regulating a bias voltage of the power amplifier according to a level of the rectified input signal from the rectifying unit.

Abstract: A power amplifier may include: an amplification unit amplifying a power level of an input signal, a negative feedback circuit unit connected between an input terminal and an output terminal of the amplification unit and a linearization circuit unit connected between the negative feedback circuit unit and the input terminal of the amplification unit to predistort and linearize a signal from the negative feedback circuit unit, and to provide the signal to the input terminal of the amplification unit.

Abstract: There is provided a power amplifier capable of increasing linear output power and efficiency without sacrificing an overall gain by employing a vector modulation function in a driving stage, with no separate vector modulator. The power amplifier includes a driving stage performing vector-modulation on an input RF signal to provide an I channel signal and a Q channel signal having different phases and amplifying the I channel signal and the Q channel signal to set gains; and a power stage amplifying power levels of the signals amplified by the driving stage.

Abstract: There is provided a power amplifier module having a bias circuit, in which a bias power is supplied to an amplifier by differently setting an impedance between an input signal terminal and a reference power terminal and an impedance between the input signal terminal and a ground. The power amplifier module includes: an amplifier unit receiving a bias power to amplify an input signal; and a bias unit supplying the bias power to the amplifier, by differently setting an impedance between an input signal terminal transmitting the input signal therethrough and a reference power terminal transmitting a reference power having a predetermined voltage level and an impedance between the input signal terminal and a ground.

Abstract: There are provided a control circuit for a digitally controlled oscillator and a control apparatus for a digitally controlled oscillator using the same. The control circuit for a digitally controlled oscillator includes: a peak detection circuit detecting amplitude of a signal output from the digitally controlled oscillator; and a transconductance control circuit comparing an output of the peak detection circuit with a predetermined reference signal to control a transconductance value of a negative transconductance circuit included in the digitally controlled oscillator.

Abstract: There is provided a digitally controlled oscillator. The digitally controlled oscillator includes a resonance circuit unit generating a resonance signal according to an equivalent capacitance formed by a parallel connection between a first capacitance varied depending on a digital control code and a second capacitance varied depending on an inverted digital control code generated by inverting the digital control code, and preset inductance; and an oscillation circuit unit providing negative resistance to the resonance circuit unit and forming oscillation conditions in the resonance circuit unit.

Abstract: Disclosed herein are a transformer and a method of manufacturing the same. The transformer includes: a primary side winding having a loop shape; a secondary side winding formed on the same plane as that of the primary side winding in a remaining section except for at least a section at which it intersects with the primary side winding and having the same loop shape as that of the primary side winding so as to be electromagnetically coupled to the primary side winding; and an intersecting section formed so that the primary side and secondary side windings having the sum of the turn numbers of 3 or more intersect with each other in a two-layer structure, wherein the intersecting section includes at least one point of intermediate node having one side connected in a first layer and the other side connected in a second layer.