Methods and devices are described for compensating an effect of aging due to, for example, hot carrier injection, or other device degradation mechanisms affecting a current flow, in an RF amplifier. In one case a replica circuit is used to sense the aging of the RF amplifier and adjust a biasing of the RF amplifier accordingly.

Provided is a current-to-voltage conversion circuit, including: an input/output node configured to input a current signal including a direct current component and an alternating current component, and to output a voltage based on the current signal; an amplification unit configured to input the voltage of the input/output node; an extraction unit configured to output a voltage based on a direct current component of a voltage output from the amplification unit; a first current supply unit configured to supply a current based on the voltage output from the extraction unit to the input/output node; and a second current supply unit configured to supply a current based on the alternating current component of the current signal to the input/output node. The current supplied by the second current supply unit corresponds to a difference between a current of the current signal and the current supplied by the first current supply unit.

Provided is a current-to-voltage conversion circuit, including: an input/output node configured to input a current signal including a direct current component and an alternating current component, and to output a voltage based on the current signal; an amplification unit configured to input the voltage of the input/output node; an extraction unit configured to output a voltage based on a direct current component of a voltage output from the amplification unit; a first current supply unit configured to supply a current based on the voltage output from the extraction unit to the input/output node; and a second current supply unit configured to supply a current based on the alternating current component of the current signal to the input/output node. The current supplied by the second current supply unit corresponds to a difference between a current of the current signal and the current supplied by the first current supply unit.

Disclosed is a transimpedance amplifier, comprising a first-stage trans-conductance amplifier TCA, a second-stage TCA, a third-stage amplifier and a feedback circuit. The first-stage TCA is electrically connected to an input current source to receive a first input signal, and outputs a first output signal. The second-stage TCA is electrically connected to the first-stage TCA to receive the first output signal, and outputs a second output signal. The third-stage amplifier is electrically connected to the second-stage TCA to receive the second output signal, and outputs a third output signal. One end of the feedback circuit is electrically connected to the input of the first-stage TCA, and the other end of the feedback circuit is electrically connected to the output of the third-stage amplifier to stabilize the third output signal. The third-stage amplifier is composed of a first output stage and a second output stage.

An embodiment amplifier circuit includes a pair of subcircuits that includes a first subcircuit and a second subcircuit, each of which includes a buffer amplifier and a feedback circuit that includes a feedback capacitor. The amplifier circuit also includes a pair of output terminals. The first subcircuit and the second subcircuit each generate a different output signal of a pair of output signals that includes a first output signal and a second output signal. The amplifier circuit is configured for receiving a positive differential input signal at the first subcircuit, receiving a negative differential input signal at the second subcircuit, and receiving the pair of output signals at the pair of output terminals. The amplifier circuit is also configured for transmitting the first output signal to the feedback circuit of the first subcircuit, and transmitting the second output signal to the feedback circuit of the second subcircuit.

Methods and devices for reducing gate node instability of a differential cascode amplifier are presented. Ground return loops, and therefore corresponding parasitic inductances, are eliminated by using voltage symmetry at nodes of two cascode amplification legs of the differential cascode amplifier. Series connected capacitors are coupled between gate nodes of pairs of cascode amplifiers of the two cascode amplification legs so to create a common node connecting the two capacitors. In order to reduce peak to peak voltage variation at the common node under large signal conditions, a shunting capacitor is connected to the common node.

A system that incorporates teachings of the present disclosure may include, for example, adjusting a tuning state of a matching network of the communication device, selecting a power offset from among a group of power offsets where the selected power offset is associated with a sub-band of operation of the communication device, and adjusting a value associated with a measured receive power or a transmit power of the communication device based on the selected power offset to generate an offset power value. Additional embodiments are disclosed.

A method for improving circuit stability is disclosed. In the method of the present invention, the circuit is analyzed to find the frequency band in which the input impedance at a target node behaves as a negative resistance, and then find the signal path of the frequency band in the matching circuit in front of the target node and add an attenuator in the signal path. This prevents the circuit from oscillation and improves the stability of the circuit. Furthermore, the signal on the main signal path will not be attenuated and the performance of the circuit will be maintained.

A method for improving circuit stability is disclosed. In the method of the present invention, the circuit is analyzed to find the frequency band in which the input impedance at a target node behaves as a negative resistance, and then find the signal path of the frequency band in the matching circuit in front of the target node and add an attenuator in the signal path. This prevents the circuit from oscillation and improves the stability of the circuit. Furthermore, the signal on the main signal path will not be attenuated and the performance of the circuit will be maintained.

An ion detection current conversion circuit includes a conversion amplifier coupled with a conversion resistor assembly for converting an ion detection current produced by an ion detector into an ion detection voltage, the conversion resistor assembly comprising a resistor having a high resistance and a capacitive compensation element, and a compensation voltage circuit for deriving a compensation voltage from the ion detection voltage and feeding the compensation voltage to the capacitive compensation element, the compensation voltage circuit comprising a variable resistor for adjusting the compensation voltage.