| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching amplifier apparatus for generating optional continuous waveform which is suitable for driving a gradient coil of a magneto- resonance imaging(MRI) apparatus. SOLUTION: A partial voltage back regulator (66) controls a high voltage bus for a total bridge circuit (52) in order to reduce total switching loss and distribute such switching loss. When a high output voltage is required and when low voltage devices (60, 62) of back regulator are switched to the PWM (Pulse Width Modulation) system and a low output voltage is required, a high voltage device of bridge is switched to the PWM system. The optimum performance for a predetermined magneto-resonance image sequence can be attained by regulating an input bus voltage with the variable input power supply (55) which may be operated in the high power factor mode. |
