A radio-frequency coil assembly (120, 660) for acquiring magnetic resonance signals, comprising: - at least one radio-frequency receive coil (246-x) configured for acquiring the MR signals; - a detune circuit (248-x) comprising one or more circuit arms (A, B) serially coupled to the at least one RF receive coil (246-x), each of the one or more circuit arms (A B) having at least two low-loss switches (350, 352, 450,452, 462,466) serially coupled to each other; - a charge control circuit (372, 472) coupled (372, 472) to each of the one or more circuit arms (A, B) at a location that is between the at least two serially-coupled low-loss switches (350, 352, 450,452, 462,466) of each of the one or more circuit arms (A, B) and configured to draw power from the RF receive coil (246-x) during a detune state; and - an energy storage device (252, 370, 470) coupled to the charge control circuit (372, 472) and configured to store the drawn power, characterized in that - the charge control circuit further comprises at least one power control switch (368,469) configured to selectively control the draw of power from the RF receive coil (246-x), - the at least one power control switch being coupled in series with the energy storage device (252,370,470) and to each of the one or more circuit arms at a location that is between the at least two serially-coupled loss switches of each of the one or more circuit arms and wherein - the detune circuit (248-x) is configured to control impedance of the receive coil (246-x) to tune or detune the receive coil (246-x) during tune or detune states, wherein the at least one power control switch (368, 468) is configured for control of its duty cycle of conductivity by a charge control signal, thereby allowing to control an amount of charge delivered to the energy storage device, wherein fine temporal modification of the charge control signal allows a desired amount of power to be extracted from the RF receive coil (246-x) coupled to the detune circuit (248-x). - at least one radio-frequency receive coil (246-x) configured for acquiring the MR signals; - a detune circuit (248-x) comprising one or more circuit arms (A, B) serially coupled to the at least one RF receive coil (246-x), each of the one or more circuit arms (A B) having at least two low-loss switches (350, 352, 450,452, 462,466) serially coupled to each other; - a charge control circuit (372, 472) coupled (372, 472) to each of the one or more circuit arms (A, B) at a location that is between the at least two serially-coupled low-loss switches (350, 352, 450,452, 462,466) of each of the one or more circuit arms (A, B) and configured to draw power from the RF receive coil (246-x) during a detune state; and - an energy storage device (252, 370, 470) coupled to the charge control circuit (372, 472) and configured to store the drawn power, - the charge control circuit further comprises at least one power control switch (368,469) configured to selectively control the draw of power from the RF receive coil (246-x), - the at least one power control switch being coupled in series with the energy storage device (252,370,470) and to each of the one or more circuit arms at a location that is between the at least two serially-coupled loss switches of each of the one or more circuit arms and wherein - the detune circuit (248-x) is configured to control impedance of the receive coil (246-x) to tune or detune the receive coil (246-x) during tune or detune states, wherein the at least one power control switch (368, 468) is configured for control of its duty cycle of conductivity by a charge control signal, thereby allowing to control an amount of charge delivered to the energy storage device, wherein fine temporal modification of the charge control signal allows a desired amount of power to be extracted from the RF receive coil (246-x) coupled to the detune circuit (248-x).