Stacked high/low voltage level H-bridge circuit for gradient amplifier of MRI system

As an essential component in magnetic resonance imaging (MRI) systems, the gradient amplifier plays an important role for good image quality. A platform of stacked high and low level H-Bridge circuit is built to fit the high-dynamic and high-steady requirements of the gradient amplifier. Both high current slew rating and low steady ripple can be achieved by using the two H-Bridges, one with high voltage rating and the other with low voltage rating. Using a duel-DSP based controller, complex algorithms can be implemented. A feed forward control with low-pass filter is proposed, and its effect is validated by experimental results on the platform.