The invention relates to a signal amplifier circuit for amplifying a signal, in particular an audio amplifier circuit, includes at least one first amplifier transistor (Q1) and at least one second amplifier transistor (Q2), wherein the first amplifier transistor (Q1) and the second amplifier transistor (Q2) are connected to one another in a push-pull circuit and are fed by an amplifier voltage source (V+, V−); and one or more bias diodes (D1, D2) thermally coupled in each case to an associated amplifier transistor (Q1, Q2), wherein the bias diodes (D1, D2) are arranged in a parallel connection with respect to the amplifying transistors (Q1, Q2) to reduce or avoid a crossover distortion, wherein the bias diodes (D1, D2) are fed at least partly by a voltage source (UA) which is independent of the amplifier voltage source (V+, V−). The invention furthermore relates to a system and a voltage converter for providing an output-side DC voltage, including a first transformer (T1) and a second transformer (T2) connected to the first transformer (T1).

A logarithmic amplifier circuit includes an adaptive gain amplifier circuit and a transistor. The adaptive gain amplifier circuit includes a gain stage and a diode. The gain stage includes an input terminal, and an output terminal. The diode includes a cathode terminal coupled to the output terminal, and an anode terminal coupled to a common terminal. The transistor includes a first terminal coupled to the input terminal, a second terminal coupled to the common terminal, and a third terminal coupled to the output terminal.

The present invention provides a linear amplifier including an amplifier stage, a DC-shifting stage, a compensation network and a power stage. The amplifier stage is configured to generate a first signal and a second signal. The DC-shifting stage is configured to adjust a DC voltage of the first signal and a DC voltage of the second signal to generate an adjusted first signal and an adjusted second signal. The compensation network is configured to generate a first driving signal and a second driving signal according to the first signal, the second signal, the adjusted first signal and the adjusted second signal. The power stage is configured to generate an output signal according to the first driving signal and the second driving signal.

There are disclosed various methods and apparatuses. In some embodiments of the method an input signal is provided to an input of a first transistor of a push-pull circuit via a first slew-rate adjuster; and the input signal is also provided to an input of a second transistor of the push-pull circuit via a second slew-rate adjuster. The input signal is effected by the first slew-rate adjuster and the second slew-rate adjuster to switch the first transistor on after the second transistor switches off when the amplitude of the input signal increases. The input signal is effected by the first slew-rate adjuster and the second slew-rate adjuster the input signal to switch the second transistor on after the first transistor switches off when the amplitude of the input signal decreases. In some embodiments the apparatus comprises a push-pull circuit comprising a first transistor and a second transistor; an input to receive an input signal; a first slew-rate adjuster adapted to provide the input signal to the input of the first transistor; and a second slew-rate adjuster adapted to provide the input signal to the input of the second transistor. A time constant of the first slew-rate adjuster is dependent on the direction of change of the input signal, and a time constant of the second slew-rate adjuster is dependent on the direction of change of the input signal.

A radio-frequency (RF) amplifier circuit facilites carrier-aggregation (CA) operation in a wireless communication network. A first amplifier subcircuit is coupled to an input node, and a second amplifier subcircuit is coupled to the input node. An amplifier subcircuit selector is to selectively enable operation of the first amplifier subcircuit, the second amplifier subcircuit, or the first and the second amplifier subcircuits together, in response to a selection indication. A reactive coupling network is arranged to selectively adjust the input impedance at the input node in response to the selection indication to reduce the input impedance variation.

An apparatus can include tracking circuitry coupled to a current source and configured to generate a reference voltage signal based on a reference current signal from the current source. The apparatus can include voltage regulator circuitry coupled to the tracking circuitry and configured to generate a voltage supply signal based on the reference voltage signal. The apparatus can further include amplifier circuitry configured to amplify an input signal based on the voltage supply signal. The reference voltage signal can track process and temperature variations associated with at least one field effect transistor within the tracking circuitry. The voltage regulator circuitry can be configured to operate with a closed loop gain higher than 1. The tracking circuitry includes a first transistor connected in parallel with a second transistor, the first and second transistors having a complimentary type with each other (e.g., NMOS and PMOS transistors).

The invention relates to a signal amplifier circuit for amplifying a signal, in particular an audio amplifier circuit, includes at least one first amplifier transistor (Q1) and at least one second amplifier transistor (Q2), wherein the first amplifier transistor (Q1) and the second amplifier transistor (Q2) are connected to one another in a push-pull circuit and are fed by an amplifier voltage source (V+, V−); and one or more bias diodes (D1, D2) thermally coupled in each case to an associated amplifier transistor (Q1, Q2), wherein the bias diodes (D1, D2) are arranged in a parallel connection with respect to the amplifying transistors (Q1, Q2) to reduce or avoid a crossover distortion, wherein the bias diodes (D1, D2) are fed at least partly by a voltage source (UA) which is independent of the amplifier voltage source (V+, V−). The invention furthermore relates to a system and a voltage converter for providing an output-side DC voltage, including a first transformer (T1) and a second transformer (T2) connected to the first transformer (T1).

The invention relates to a signal amplifier circuit for amplifying a signal, in particular an audio amplifier circuit, includes at least one first amplifier transistor (Q1) and at least one second amplifier transistor (Q2), wherein the first amplifier transistor (Q1) and the second amplifier transistor (Q2) are connected to one another in a push-pull circuit and are fed by an amplifier voltage source (V+, V−); and one or more bias diodes (D1, D2) thermally coupled in each case to an associated amplifier transistor (Q1, Q2), wherein the bias diodes (D1, D2) are arranged in a parallel connection with respect to the amplifying transistors (Q1, Q2) to reduce or avoid a crossover distortion, wherein the bias diodes (D1, D2) are fed at least partly by a voltage source (UA) which is independent of the amplifier voltage source (V+, V−). The invention furthermore relates to a system and a voltage converter for providing an output-side DC voltage, including a first transformer (T1) and a second transformer (T2) connected to the first transformer (T1).

A DC-DC converter according to an embodiment is a DC-DC converter for generating an output voltage VOUT according to a reference voltage VREF, and includes a fully differential amplifier that outputs a first differential output signal and a second differential output signal according to a differential input using the reference voltage VREF and the output voltage VOUT, a pulse width modulation signal generation circuit that generates a pulse width modulation signal based on the first differential output signal Vout1 and the second differential output signal Vout2, and a driver that outputs a driving signal obtained by waveform-shaping the pulse width modulation signal.

An amplifier circuit includes, a first transistor and a first resistor connected in series between a power supply voltage and an output terminal. A second transistor and a second resistor are connected in series between the output terminal and a ground reference voltage. There is a first operational amplifier and a second operational amplifier. A first detection current corresponding to a voltage drop across first resistor is generated. A second detection current corresponding to a voltage drop across the second resistor is generated. A first replication circuit subtracts the second detection current from the first detection current. A third resistor conducts the current obtained by subtracting the second detection current from the first detection current.