Power stage of amplifier/transmitter for magneto-resonance tomograph, transmitter, radar

摘要

The power stage has a matching circuit with a control loop (3,3') associated with each of several parallel transistors (1,1'). Each control loop contains an integration circuit (6,6') with an operational amplifier function (7,7') and a charge storage capacitor (8,8') with a serial resistor (9,9'). The series circuit contg. the resistor and capacitor is connected between the source and gate (2) of its associated transistor via a switch (10,10'). The operational amplifier output is connected to the capacitor gate junction; its positive input is connected in parallel with the capacitor; its negative input is connected to a common controllable potential for all control loops. Switches which can open and close each control loop in each link between a source and integration circuit are connected to the common controller (12).