Abstract:
An impedance circuit includes a poly-resistor and a controller. The poly-resistor has a first terminal and a second terminal. The controller generates a first control voltage and a second control voltage. The resistance between the first terminal and the second terminal of the poly-resistor is determined according to the first control voltage and the second control voltage. The second control voltage is different from the first control voltage. The proposed impedance circuit can improve the linearity of the poly-resistor.
Abstract:
A high-linearity amplifier including a main operational amplifier, a feedback circuit, and a compensation circuit is shown. The feedback circuit couples an output signal of the main operational amplifier to an input port of the main operational amplifier. The compensation circuit couples a former-stage circuit of the amplifier to the input port of the main operational amplifier to compensate for the non-linearity of the feedback circuit. The compensation circuit and the feedback circuit form an inverse paralleling linearization architecture. In the inverse paralleling linearization architecture, a resistor in the feedback circuit corresponds to a resistor in the compensation circuit which is biased in an inversed way in comparison with the corresponding resistor in the feedback circuit.
Abstract:
An amplifier circuit with in-band gain degradation compensation is shown. The amplifier circuit has an input-stage amplifier, at least one intermediate-stage amplifier, and an output-stage amplifier cascaded between an input port and an output port of the amplifier circuit. A compensation capacitor is coupled between the output port of the amplifier circuit and an output port of the input-stage amplifier. A high-order damping circuit is coupled to an output port of the intermediate-stage amplifier.
Abstract:
An impedance circuit includes a first poly-resistor and a second poly-resistor. The first poly-resistor has a first terminal coupled to a first node, and a second terminal coupled to a second node. The second poly-resistor has a first terminal coupled to the first node, and a second terminal coupled to the second node. The resistance between the first terminal and the second terminal of the first poly-resistor is determined according to a first control voltage. The resistance between the first terminal and the second terminal of the second poly-resistor is determined according to a second control voltage. The first control voltage and the second control voltage are determined according to a first voltage at the first node and a second voltage at the second node.
Abstract:
An audio codec system which uses a memory to buffer frames of audio while signal power levels of the frames of audio buffered in the memory are detected to generate a signal power look-forward value and zero-crossing points of the frames of audio buffered in the memory are detected to obtain available calibration points for gain control due to a change of the signal power look-forward value. The gain control is divided to be performed at the available calibration points.
Abstract:
A high-linearity amplifier including a main operational amplifier, a feedback circuit, and a compensation circuit is shown. The feedback circuit couples an output signal of the main operational amplifier to an input port of the main operational amplifier. The compensation circuit is coupled to the input port of the main operational amplifier to compensate for the non-linearity of the feedback circuit. A signal coupled to the input port of the main operational amplifier through the compensation circuit has an inverse phase compared to the output signal of the main operational amplifier.
Abstract:
A circuit for low-noise reference signal generation comprising a filter unit and a functional unit. The filter unit comprises a transistor and an energy storage component. The transistor comprises a first node, a second node, a control node and a body node. The first node is configured to receive an input signal. The second node is configured to output a filtered signal. The control node is configured to receive a control signal for controlling the transistor to turn on or off. The body node is configured to couple to the input signal, the output signal or a signal which is similar to the input signal or the output signal. The energy storage component is coupled to the second node of the transistor. The functional unit is coupled to the second node of the transistor and the energy storage component. The functional unit has high input impedance.
Abstract:
An amplifier circuit is disclosed. The amplifier circuit includes a detection circuit, a control amplifier circuit and an output stage. The detection circuit detects disturbances occurring in a first supply voltage and provides detection results. The control amplifier circuit controls a first voltage provided to a first control node and a second voltage provided to a second control node in response to the detection results. The output stage circuit includes a first output power transistor coupled to the control amplifier circuit at the first control node and a second output power transistor coupled to the control amplifier circuit at the second control node. The first voltage and the second voltage are controlled differently when a disturbance is detected to have occurred.