Patent ID: 6525604
Filing Date: 2003-02-25
Classification: H03F,H03K

Abstract:
An amplifier circuit including an inverting differential amplifier having an output signal with a limited amplitude, said circuit comprising:a differential amplifier having an inverting input, a non-inverting input, and an amplifier output; a first negative feedback branch adapted to limit a positive amplitude of an output signal of said amplifier output of said differential amplifier; a second negative feedback branch adapted to limit a negative amplitude of said output signal; a control unit having a control signal output and a programming signal input; a first supply voltage lead adapted to provide a first supply voltage; and a second supply voltage lead adapted to provide a second supply voltage; wherein: said first negative feedback branch includes a first threshold value switch that comprises a first adjustable current source, a first resistor, and a first transistor having a control terminal and two controlled terminals; said first adjustable current source and said first resistor are connected in series with each other between said first supply voltage lead and said amplifier output, and form a first voltage divider with a first voltage divider output between said first adjustable current source and said first resistor; said first voltage divider output is connected with said control terminal of said first transistor; one of said two controlled terminals of said first transistor is connected with said inverting input of said differential amplifier and another of said two controlled terminals of said first transistor is either connected with said first supply voltage lead or connected with said amplifier output of said differential amplifier; said first adjustable current source is connected with said control signal output of said control unit; said second negative feedback branch includes a second threshold value switch that comprises a second adjustable current source, a second resistor, and a second transistor having a control terminal and two controlled terminals; said second adjustable current source and said second resistor are connected in series with each other between said second supply voltage lead and said amplifier output, and form a second voltage divider with a second voltage divider output between said second adjustable current source and said second resistor; said second voltage divider output is connected with said control terminal of said second transistor; one of said two controlled terminals of said second transistor is connected with said inverting input of said differential amplifier and another of said two controlled terminals of said second transistor is either connected with said second supply voltage lead or connected with said amplifier output of said differential amplifier; and said second adjustable current source is connected with said control signal output of said control unit.