A circuit includes a first system-on-chip (SoC) driven by a first clock generator and a second SoC driven by a second clock generator where the first clock generator and the second clock generator have independent time bases. The first and second clock generators are synchronized using an RLC circuit external to the first clock generator and the second clock generator that converts an output of the first clock generator into current pulses and injects the current pulses into the second clock generator to pull an output of the second clock generator into synchronization with the output of the first clock generator. The RLC circuit converts a voltage output of the first clock generator into current pulses at the resonant frequency or specific harmonics of the output of the first clock generator. The second clock generator may include a ring oscillator into which the current pulses are injected.

A circuit arrangement is provided which includes an array of stages for photon counting current to voltage conversion. Each stage includes a tunable operational transconductance amplifier and a feedback network forming a feedback loop of the operational transconductance amplifier. Each stage is configured to provide an output signal as a function of an input signal that is provided to the amplifier input of the operational transconductance amplifier, wherein the input signal comprises one or more current pulses and the output signal comprises one or more voltage pulses. With the tunable operational transconductance amplifier the transconductance of a stage can be tuned so that differences in peaking time and gain are avoided. Furthermore, an imaging device and a method for operating a circuit arrangement are provided.

A shaper circuit includes a first amplifier including an input and an output, the input being configured to receive an input signal, which includes one or more current pulses, a feedback component coupled to the output and to the input of the first amplifier thereby forming a feedback loop of the first amplifier, and an RC component coupled to the output of the first amplifier and to a reference potential terminal. Therein the shaper circuit is configured to provide an output signal as a function of the input signal, the output signal including one or more voltage pulses, and the RC component is configured to largely cancel a low frequency pole of the feedback loop of the first amplifier.

An amplifier circuit includes a voltage-to-current conversion circuit and a current-to-voltage conversion circuit. The voltage-to-current conversion circuit generates a current signal according to an input voltage signal, and includes an operational transconductance amplifier (OTA) used to output the current signal at an output port of the OTA. The current-to-voltage conversion circuit generates an output voltage signal according to the current signal, and includes a linear amplifier (LA), wherein an input port of the LA is coupled to the output port of the OTA, and the output voltage signal is derived from an output signal at an output port of the LA.

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 amplifier circuit comprises a differential input stage and a differential output stage. The differential input stage includes a first differential input transistor pair coupled to a differential input of the amplifier circuit, and a second differential input transistor pair coupled to the differential input and the differential output stage; a degeneration impedance coupled between first transistors of the first and second differential input transistor pairs and second transistors of the first and second differential input transistor pairs; and a feedback circuit coupled to the first and second differential input transistor pairs and the degeneration impedance, wherein output current is provided from the differential input stage to the differential output stage by the feedback circuit and transition current is provided to the output stage by the second differential input transistor pair.

A switched capacitor amplifier circuit includes an operational amplifier, a first capacitor and a second capacitor each having one end connected to a negative input terminal of the operational amplifier, a first switching circuit configured to connect the other end of the first capacitor and a signal source during a first operation, a second switching circuit configured to connect the other end of the second capacitor and the output terminal of the operational amplifier so as to connect the output terminal and the negative input terminal of the operational amplifier through the second capacitor during the second operation, and an impedance converter circuit configured to convert an output impedance of the signal source into a specified impedance, the impedance converter circuit being connected between the first switching circuit and the other end of the first capacitor.

A switched capacitor amplifier circuit includes an operational amplifier, a first capacitor and a second capacitor each having one end connected to a negative input terminal of the operational amplifier, a first switching circuit configured to connect the other end of the first capacitor and a signal source during a first operation, a second switching circuit configured to connect the other end of the second capacitor and the output terminal of the operational amplifier so as to connect the output terminal and the negative input terminal of the operational amplifier through the second capacitor during the second operation, and an impedance converter circuit configured to convert an output impedance of the signal source into a specified impedance, the impedance converter circuit being connected between the first switching circuit and the other end of the first capacitor.

An amplifier circuit comprises a differential input stage and a differential output stage. The differential input stage includes a first differential input transistor pair coupled to a differential input of the amplifier circuit, and a second differential input transistor pair coupled to the differential input and the differential output stage; a degeneration impedance coupled between first transistors of the first and second differential input transistor pairs and second transistors of the first and second differential input transistor pairs; and a feedback circuit coupled to the first and second differential input transistor pairs and the degeneration impedance, wherein output current is provided from the differential input stage to the differential output stage by the feedback circuit and transition current is provided to the output stage by the second differential input transistor pair.

In an embodiment an integration circuit has a first input terminal configured to receive a first input signal, a second input terminal configured to receive a second input signal, an output terminal to provide an output signal as a function of the first and the second input signal, a first and a second amplifier, each being switchably connected between the first or the second input terminal and the output terminal, and a capacitor which is switchably coupled in a feedback loop either of the first or of the second amplifier such that the capacitor and one of the first and the second amplifier form an inverting integrator providing the output signal. Therein the integration circuit is prepared to be operated in a first and a second subphase, wherein in each of first and second subphases one of the first and the second input signals is supplied to the inverting integrator and the respective other one of first and the second input signals is supplied to the respective other one of the first and the second amplifier.