Low offset voltage transistor bridge transconductance amplifier

Claim 1

A transconductance amplifier comprising: a differential input stage operative for accepting a voltage signal input and including: first and second transistors having their base electrodes connected together to receive a common bias signal, first and second resistors connected in series with first and second emitter electrodes of the first and second transistors respectively, and the first and second resistors being connected to sense the voltage signal input; whereby a series connection of the first resistor, a base emitter junction of the first transistor, a base emitter junction of the second transistor and the second resistor are connected in parallel with the voltage signal input a current mirror source including third, fourth and fifth transistors and the third and fourth transistors being coupled to supply current to collector electrodes of the first and second transistors respectively, and the fifth transistor being coupled jointly to a base electrode of the third and fourth transistors for controlling a base current therein, and output means coupled to a node joining the second and fourth transistors and including a sixth transistor for providing a current feedback signal connected to the second emitter.