Patent ID: 7224214

Claim:
An integrated circuit, comprising: an input terminal for applying an input signal with a high and a low level, the input signal having a DC component; a first amplifier circuit for generating a first control signal with a first input terminal connected to the input terminal for applying the input signal; second amplifier circuit for generating a second control signal with a second input terminal connected to the input terminal for applying the input signal; and a third amplifier circuit including a first controllable resistor with a control terminal and a second controllable resistor with a control terminal, the control terminal of the first controllable resistor of the third amplifier circuit driven with the first control signal, the control terminal of the second controllable resistor of the third amplifier circuit driven with the second control signal, wherein the first amplifier circuit driven by the high level of the input signal generates the first control signal with a first level so that the first controllable resistor of the third amplifier circuit is controlled in high-resistance fashion, the second amplifier circuit driven by the high level of the input signal generates the second control signal with a first level so that the second controllable resistor of the third amplifier circuit is controlled in low-resistance fashion, the first level of the first control signal and the first level of the second control signal being independent of the level of the DC component of the input signal, and wherein the first amplifier circuit driven the low level of the input signal generates the first control signal with a second level so that the first controllable resistor of the third amplifier circuit is controlled in low-resistance fashion, the second amplifier circuit driven by the low level of the input signal generates the second control signal with a second level so that the second controllable resistor of the third amplifier circuit is controlled in high-resistance fashion, the second level of the first control signal and the second level of the second control signal being independent of the level of the DC component of the input signal.