The present invention relates to a novel and inventive compound device structure for a low noise current amplifier or trans-impedance amplifier. The trans-impedance amplifier includes an amplifier portion, which converts current input into voltage using a complimentary pair of novel n-type and p-type current field-effect transistors (NiFET and PiFET) and a bias generation portion using another complimentary pair of NiFET and PiFET. Trans-impedance of NiFET and PiFET and its gain may be configured and programmed by a ratio of width (W) over length (L) of source channel over the width (W) over length (L) of drain channel (W/L of source channel/W/L of drain channel).

An operational amplifier and a differential amplifying circuit thereof. The differential amplifying circuit receives a differential input signal and outputs a differential output signal. The differential amplifying circuit includes an output port that has a first terminal and a second terminal, the differential output signal being outputted via the first and second terminals; a first transistor pair receiving the differential input signal via two first ends and coupling to the first and second terminals respectively via two second ends; a second transistor pair receiving the differential input signal via two first ends and coupling to the first and second terminals respectively via two second ends; and a third transistor pair receiving a control signal via two first ends and coupling to the first and second terminals respectively via two second ends. The control signal controls the third transistor pair to switch on or off and/or controls the current flowing therethrough.

An amplifier circuit a differential input stage coupled to a first input and to a second input between which a differential input voltage is present. A converter stage is coupled to the input stage to convert the differential input voltage into a converted voltage. An output stage is coupled to the converter stage and generates, starting from the converted voltage, an output voltage on a single output of the amplifier circuit. A biasing stage is coupled to the input stage and to the output stage to supply a biasing current. A chopper module reduces a contribution of offset and noise associated with the output voltage. The chopper module is coupled to the input stage, converter stage, and to the biasing stage. The chopper module includes an input chopper stage, a converter chopper stage, and a biasing chopper stage that operate jointly under control of a chopper signal.

A circuit with Miller compensation effect includes a first stage and a second stage, with a first terminal for receiving a bias current and a second terminal that can be coupled to ground, wherein the first stage includes a differential stage coupled via a coupling line to the second stage. The second stage includes a transistor with a Miller compensation network, which is set between the first terminal of the second stage and the control terminal of the aforesaid transistor. A compensation-control transistor, which is coupled to the second terminal of said differential stage, can be activated for coupling the aforesaid second terminal to ground, the compensation-control transistor having its control terminal coupled to the aforesaid coupling line between the first and second stages.

In a folded cascode operational amplifier circuit, a source is connected to a back gate in each of third and fourth transistors that are cascode-connected to first and second transistors, which are an electric current source that returns an electric current signal output by a differential pair of an input stage. In the third and fourth transistors, an active parasitic element exists due to its device structure. When a falling edge signal of a rectangular wave is input, and electric current is supplied to the source of the third transistor to increase its electric potential, electric current flows into the drain from the back gate via the active parasitic element in an on state, in order to rapidly charge a capacitor. Thereby, a fifth transistor turns on within a shorter time, in order to improve an internal slew rate.

A variable current trans-impedance amplifier (TIA) for an ultrasound device is described. The TIA may be coupled to an ultrasonic transducer to amplify an output signal of the ultrasonic transducer representing an ultrasound signal received by the ultrasonic transducer. During acquisition of the ultrasound signal by the ultrasonic transducer, one or more current sources in the TIA may be varied.

A variable current trans-impedance amplifier (TIA) for an ultrasound device is described. The TIA may be coupled to an ultrasonic transducer to amplify an output signal of the ultrasonic transducer representing an ultrasound signal received by the ultrasonic transducer. During acquisition of the ultrasound signal by the ultrasonic transducer, one or more current sources in the TIA may be varied.

An amplification circuit according to the present embodiment includes a first amplifier, a second amplifier, a capacitor, and an adjustment circuit. The first amplifier amplifies an input signal and outputs a first amplified signal. The second amplifier amplifies the first amplified signal input from the first amplifier through a connection line and outputs a second amplified signal. The capacitor is arranged between the connection line and an output line through which the second amplifier outputs the second amplified signal. The adjustment circuit changes a charge/discharge state of the capacitor according to a value of the input signal.

A variable current trans-impedance amplifier (TIA) for an ultrasound device is described. The TIA may be coupled to an ultrasonic transducer to amplify an output signal of the ultrasonic transducer representing an ultrasound signal received by the ultrasonic transducer. During acquisition of the ultrasound signal by the ultrasonic transducer, one or more current sources in the TIA may be varied.

The invention generally relates to amplifier circuits for coupling and/or driving an inductive load with a time-continuous current. Example embodiments of the amplifier circuits disclosed herein may for example be used for driving, for example, electrodynamic converters that generate acoustic pressure, which may be in form of a System-on-Chip (SoC) or a System-in-Package (SiP).