Differential current amplifier

A current amplifier comprising:

• a bias current source;
• first and second like transistors having input, output and common electrodes, said common electrodes interconnected at a common terminal to configure said first and second transistors as a differential pair;
• means for connecting said bias current source for providing bias current to said common terminal;
• third, fourth, fifth and sixth like transistors having respective input, output and common electrodes and being a conductivity type complementary to said first and second transistors;
• means for connecting the common electrodes of the third and fourth transistors;
• means for connecting the common electrodes of the fifth and sixth transistors;
• means for providing respective operating currents to the common electrodes of the third and fourth transistors and to the common electrodes of the fifth and sixth transistors;
• means for connecting the output electrode of the first transistor to the input electrodes of the third and fourth transistors;
• means for connecting the output electrode of the second transistor to the input electrodes of the fifth and sixth transistors;
• respective means for connecting the output electrodes of the third and fifth transistors to the output electrodes of the first and second transistors respectively;
• respective means for connecting the output electrodes of the fourth and sixth transistors directly to the input electrodes of the second and first transistors respectively.

A current amplifier comprising:

• a current bias source;
• a differential input circuit having a common terminal, first and second differential input terminals and first and second differential current output terminals, wherein output signal at said second output terminal is in phase with signal applied to said first differential input terminal;
• means connecting the current bias source to said common terminal;
• a first CMA having an input and first, second and third output terminals;
• a second CMA having an input and first and second output terminals;
• a third CMA having an input and first output terminal;
• a fourth CMA having an input and first and second output terminals;
• respective means for connecting the input terminals of the first and second CMA's to the first and second differential current output terminals respectively;
• means for connecting the second output terminal of the second CMA to the input terminal of the fourth CMA;
• means for connecting the second output terminal of the first CMA to the input terminal of the third CMA;
• means for connecting the first output terminals of the first and fourth CMA's, to the second differential input terminal;
• means for connecting the first output terminals of the second and third CMA's to the first differential input terminal;
• and
• means for connecting the third output terminal of the first CMA to the second output terminal of the fourth CMA to form an output terminal for said current amplifier.

A current amplifier comprising:

• a current bias source;
• a signal input terminal and a signal output terminal;
• a differential input circuit having a common terminal, first and second differential input terminals and first and second differential current output terminals, wherein output signal at said second ouput terminal is in phase with signal applied to said first differential input terminal;
• means connecting the current bias source to said common terminal;
• a first current mirror amplifier having an input terminal and an output terminal;
• a second current mirror amplifier having an input terminal and an output terminal exhibiting a gain of A relative to the gain of said first current mirror amplifier;
• respective means for connecting the input terminals of the first and second current mirror amplifiers to the first and second differential output current terminals respectively;
• means for connecting the output terminal of the first current mirror amplifier directly to the signal input terminal;
• means for connecting said second differential input terminal to said signal input terminal;
• and
• means for connecting said second current mirror amplifier output terminal to said signal output terminal.