A matching circuit structure for effectively suppressing the low-frequency clutter of a power amplifier of a mobile phone, falling within the technical field of radio frequency Pas is provided. The circuit structure includes an input end, a blocking capacitor, a power amplifier (PA), an output matching network and an output end connected in series; and the matching circuit structure further includes a negative feedback network connected in parallel to a transmission end of the PA; the negative feedback network includes a resonant capacitor, a resonant inductor and a matching inductor; the resonant capacitor and the resonant inductor are connected in parallel to form a frequency selecting network, and the frequency selecting network is connected in series with the matching inductor and to the ground. The matching circuit structure above can be used to effectively suppress the low-frequency clutter of a power amplifier.

The invention relates to a class AB amplifier for receiving an input current and generating an amplified output current and having first and second output transistors connected to provide the output current, wherein if the input current is less than a threshold the first output transistor is enabled and the second output transistor is disabled, and if the input current exceeds a threshold the second output transistor is enabled.

An aspect includes an apparatus including a first amplifier; a first field effect transistor (FET) including a first source coupled to an output of the first amplifier, and a first drain for coupling to a first load; and a first gate drive circuit including an input coupled to the output of the first amplifier and an output coupled to a first gate of the first FET. Another aspect includes a method including amplifying a first audio signal using a first audio amplifier to generate a first voltage; generating a first gate voltage based on the first voltage; applying the first gate voltage to a first gate of a first field effect transistor (FET) coupled between the first audio amplifier and a first audio transducer; and applying the first voltage to a first source of the first FET.

Charge pump tracker circuitry is disclosed having a first switch network configured to couple a first flying capacitor between a voltage input terminal and a ground terminal during a first charging phase and couple the first flying capacitor between the voltage input terminal and a pump output terminal during a first discharging phase. A second switch network is configured to couple a second flying capacitor between the voltage input terminal and the ground terminal during a second charging phase and couple the second flying capacitor between the voltage input terminal and the pump output terminal during a second discharging phase. A switch controller is configured to monitor first and second voltages across the first and second flying capacitors, respectively, during the first and second discharging phases and in response to control the first and second switch networks so that the first the second discharging phases alternate in an interleaved mode.

A receiver circuit with input common mode voltage sensing is provided. The receiver circuit is applied to a controller area network and comprises a resistor assembly, connected with a high end and a low end of the controller area network, a common mode voltage sensor and a receiving amplifier. The resistor assembly bucks voltage, respectively generating the high end and low end voltage divisions at first and second nodes and outputting the voltage divisions to the receiving amplifier to generate a resultant signal to an output end of the controller area network. The common mode voltage sensor is connected between the resistor assembly and the receiving amplifier, and able to sense the common mode voltage on bus and control the voltage on center tap of the resistor assembly so the receiver circuit for controller area network can receive the differential signal with a much wider input common mode range.

Embodiments provide an amplification circuit, an apparatus for amplifying, a low noise amplifier, a radio receiver, a mobile terminal, a base station, and a method for amplifying. An amplification circuit for amplifying a radio signal comprises a first amplification stage configured to amplify an input signal, V.sub.in(t), to obtain an intermediate signal. The amplification circuit further comprises a cascoding circuit configured to amplify the intermediate signal to obtain a first output signal V.sub.outn(t). The amplification circuit further comprises a second amplification stage configured to amplify the intermediate signal to obtain a second output signal, V.sub.outp(t).

An operational amplifier includes an output node; an output stage, comprising a plurality of output current paths and a plurality of control nodes, wherein the plurality of control nodes are respectively coupled to the plurality of output current paths, and the plurality of output current paths are coupled to the output node and respectively coupled to a plurality of power supply sources providing different voltages; and a selecting unit, configured to couple an internal output node of the operational amplifier to one of the plurality of control nodes of the output stage.

In an amplifier that uses a transistor, a minimum operation voltage is lowered. An amplifier includes a P-type transistor and an N-type transistor connected in series, and an operational amplifier. An output terminal of the operational amplifier is connected to gates of both the P-type transistor and the N-type transistor. One of an inverting input terminal and a non-inverting input terminal of the operational amplifier is connected to drains of both the P-type transistor and the N-type transistor. Further, a predetermined reference voltage is applied to another of the inverting input terminal and the non-inverting input terminal.

Embodiments provide an amplification circuit, an apparatus for amplifying, a low noise amplifier, a radio receiver, a mobile terminal, a base station, and a method for amplifying. An amplification circuit (10) for amplifying a radio signal comprises a first amplification stage (12) configured to amplify an input signal, V.sub.in(t), to obtain an intermediate signal. The amplification circuit (10) further comprises a cascoding circuit (14) configured to amplify the intermediate signal to obtain a first output signal V.sub.outn(t). The amplification circuit (10) further comprises a second amplification stage (16) configured to amplify the intermediate signal to obtain a second output signal, V.sub.outp(t).

In various implementations of a load modulated balanced amplifier (LMBA), a control signal is generated (e.g., automatically generated) based at least in part on an input signal. The LBMA generally comprises a balanced amplifier, an input splitter, and a control path. A common theme of the different variants described below is that we use a nonlinear characteristic to generate a power-dependent asymmetry in the relative output power levels of the balanced and control amplifiers. This power-depended asymmetry results in dynamic load modulation of the balanced amplifiers, which in turn provides improved efficiency. In one implementation, for example, an LMBA comprises a pair of primary amplifiers collectively providing a balanced amplifier and a control amplifier coupled to the balanced amplifier and adapted to provide a control signal to the balanced amplifier. The control amplifier is adapted to automatically generate the control signal based at least in part upon the input signal to provide load modulation of the balanced amplifier.