Body coil tuning control device and magnetic resonance system

A body coil tuning control device, comprising:

• a DC-DC converter, a first low dropout linear regulator (LDO), a first resistor group, a first operational amplifier, a negative feedback circuit, a metal-oxide semiconductor field effect transistor (MOSFET) array, a second LDO, a second resistor group, a fourth operational amplifier, a seventh resistor, an eighth resistor, a ninth resistor, said first resistor group including one resistor or multiple series resistors, a structure of said second resistor group being the same as that of said first resistor group, said second LDO and said first LDO being the same LDO, and the resistance value of said seventh resistor being equal to that of said eighth resistor, wherein:
• said DC-DC converter has an input terminal connected to a DC power supply of a magnetic resonance (MRI) system and an output terminal connected to the input terminal of said first LDO, and said DC-DC converter is used to reduce a voltage of the input DC signal to a preset first voltage;
• the output terminal of said first LDO is connected to the first connection terminal of said first resistor group, and an output voltage of said first LDO is smaller than the preset first voltage;
• the input terminal of said second LDO is connected to the input terminal of said first LDO, and the output terminal of said second LDO is connected to the first connection terminal of said second resistor group;
• the second connection terminal of said second resistor group is connected to the second connection terminal of said first resistor group;
• the first connection terminal of said seventh resistor is connected to the output terminal of said first LDO, and the second connection terminal of said seventh resistor is connected to the first connection terminal of said eighth resistor;
• the first connection terminal of said eighth resistor is connected to the output terminal of said second LDO;
• a non-inverting input terminal of said fourth operational amplifier is connected to the second connection terminal of said seventh resistor;
• said ninth resistor is connected between an inverting input terminal and the output terminal of said fourth operational amplifier;
• said first operational amplifier has an inverting input terminal connected to the output terminal of said fourth operational amplifier and a non-inverting input terminal connected to the second connection terminal of said first resistor group;
• the output terminal of said first operational amplifier is connected to a gate of said MOSFET array;
• said negative feedback circuit is connected between the output terminal and the inverting input terminal of said first operational amplifier;
• a drain of said MOSFET array is connected to the second connection terminal of said first resistor group, and a source to the input terminal of the body coil of said MRI system;
• said negative feedback circuit meets a requirement that after the output signal of said first operational amplifier is input to the gate of said MOSFET array, the source of said MOSFET array can output a constant preset current;
• and
• each MOSFET in said MOSFET array is connected in parallel, and a number of MOSFETs meets a requirement that a power of each MOSFET is smaller than a preset power.