Abstract: An amplifier circuit comprising a driver (204, 304) configured to provide a switched mode input signal, a switching mode power amplifier (206, 306) configured to receive the switched mode input signal and provide an output signal for an external load (210, 310); and a sensor (208, 308) configured to sense the impedance of the external load (210, 310) The driver is configured to set the duty cycle of the switched mode input signal in accordance with the sensed impedance of the external load (210, 310).

Abstract: An amplifier circuit comprising a driver (204, 304) configured to provide a switched mode input signal, a switching mode power amplifier (206, 306) configured to receive the switched mode input signal and provide an output signal for an external load (210, 310); and a sensor (208, 308) configured to sense the impedance of the external load (210, 310) The driver is configured to set the duty cycle of the switched mode input signal in accordance with the sensed impedance of the external load (210, 310).

Abstract: It is proposed herein to improve the specifications of a low-noise amplifier (LNA) by integrating it in a chip. In order to cover a range of operating frequencies using a single chip, the integrated-circuit amplifier proposed herein comprises an input port configured to receive a magnetic resonance (MR) signal from a radio-frequency (RF) coil, one or more LNAs configured to amplify the received MR signal, and an output port configured to output the amplified MR signal from the one or more LNAs. The operating frequency of the RF coil depends on the field strength. The matching circuit, if present, needs to be tuned to operate at the operating frequency of the RF coil, and depends on the component values in the loop, thus on loop size. In contrast, the proposed integrated-circuit amplifier is capable of directly connecting to RF coils with different loop sizes, without the need for a matching circuit.

Abstract: It is proposed herein to improve the specifications of a low-noise amplifier (LNA) by integrating it in a chip. In order to cover a range of operating frequencies using a single chip, the integrated-circuit amplifier proposed herein comprises an input port configured to receive a magnetic resonance (MR) signal from a radio-frequency (RF) coil, one or more LNAs configured to amplify the received MR signal, and an output port configured to output the amplified MR signal from the one or more LNAs. The operating frequency of the RF coil depends on the field strength, The matching circuit, if present, needs to be tuned to operate at the operating frequency of the RF coil, and depends on the component values in the loop, thus on loop size. In contrast, the proposed integrated-circuit amplifier is capable of directly connecting to RF coils with different loop sizes, without the need for a matching circuit.