OPERATIONAL INSTRUMENTATION AMPLIFIER Russian patent published in 1996 - IPC

FIELD: measurement radio engineering. SUBSTANCE: operational instrumentation amplifier that has three noninverting operational amplifiers and n-p-n current mirror where outputs of first and second operational amplifiers are interconnected through first resistor and outputs of all operational amplifiers are connected to their inverting inputs, negative power lead of first operational amplifier is connected to input of n-p-n current mirror whose output is connected to noninverting input of third operational amplifier and through second resistor to ground bus while power lead of n-p-n current mirror is connected to negative power bus, is provided in addition with fourth operational amplifier, four n-p-n transistors, and third resistor; inverting input of fourth operational amplifier is connected to positive power lead of first operational amplifier and to emitter of first transistor whose collector is connected to its base, collector and base of second transistor, and positive supply lead; emitter of second transistor is connected to noniverting input of forth operational amplifier and to collectors of third and fourth transistors; base of third transistor is connected to output of fourth operational amplifier, emitter, to base of fourth transistor; emitter of third transistor is connected to base of fourth transistor and through third resistor, to emitter of fourth transistor and to noninverting input of third operational amplifier. EFFECT: reduced nonlinear distortions within comprehensive range of output current due to building all three current mirrors around n-p-n transistors. 1 dwg