Patent ID: 6900638

Claim:
A magnetic resonance imaging (MRI) system performing an MRI scan in accordance with a pulse sequence, the pulse sequence including at least a first pulse, the system comprising: a gradient coil assembly generating a gradient magnetic field during the MRI scan: an amplifier driving the gradient coil assembly such that the gradient coil assembly generates the gradient magnetic field in accordance with the pulse sequence; and a switch assembly providing a conductive path between the amplifier and the gradient coil assembly, the switch assembly comprising: a first switching device having a conductive state during a first portion of the first pulse of the pulse sequence, the first portion dependent only on the magnitude of a current applied to the gradient coil assembly by the driving amplifier; and a second switching device coupled in parallel with the first switching device, the second switching device having a conductive state during a second portion of the first pulse of the pulse sequence during which the current from the amplifier to the gradient coil assembly is below a non-zero threshold value, wherein the conductive path is provided between the amplifier and the gradient coil assembly during substantially the entire duration of the first pulse.