Remote controlled amplifier

A monolithic integrated circuit, comprising:

• a first amplifier responsive to a differential input for amplifying a signal;
• an input amplifier to receive an input signal and serve as a current source of the first amplifier;
• a second amplifier responsive to a differential input and coupled to the first amplifier to act upon an output from the first amplifier;
• and a current source for the second amplifier, the current source having an output terminal and a control terminal which is coupled to the second amplifier and controlled by a feedback loop around the second amplifier;
• and an integrated circuit output terminal coupled to the output terminal of the current source to obtain an output for the integrated circuit directly from the current source, thereby providing a circuit having an output with a magnitude which is controlled by a control voltage applied to the differential inputs of the first and second amplifiers.

A circuit capable of amplifying two signals simultaneously and having a first channel and a second channel wherein the first channel includes a first amplifier for receiving and amplifying a first input signal, a second amplifier having the first amplifier as a current source and having an output, a third amplifier coupled to the second amplifier for amplifying the output of the second amplifier, and means for providing a current source for the third amplifier and adapted to be controlled by the feedback loop around the third amplifier, the means for providing also producing an output for the first channel;

• and the second channel includes a fourth amplifier for receiving and amplifying a second input signal, a fifth amplifier having the fourth amplifier as a current source and having an output, a sixth amplifier coupled to the fifth amplifier for amplifying the output of the fifth amplifier, second means for providing a current source for the sixth amplifier and adapted to be controlled by a feedback loop around the sixth amplifier, the second means providing an output for the second channel;
• a differential amplifier having a first and a second output and an input;
• and a seventh amplifier coupled to the differential amplifier to control amplitude of the first and second outputs thereby providing signal amplitude control for the circuit and wherein the first and second outputs are for controlling the gains of the second, together with the third amplifier, and of the fifth amplifier, together with the sixth amplifier, thereby providing a balance control between the first and second channels.

An electronic circuit for amplifying a plurality of audio signals and providing balance between individual signals of the plurality of audio signals, comprising:

• a first amplifier having at least a first and a second output, the first amplifier being responsive to a balance input for providing balance between the outputs of the first amplifier;
• a second amplifier in parallel with the first amplifier for controlling amplitude of the outputs of the first amplifier and being responsive to a volume control input;
• a third amplifier for amplifying one of the plurality of audio signals and being responsive to the first output of the first amplifier;
• and a fourth amplifier for amplifying another of the plurality of audio signals and being responsive to the second input of the first amplifier.