A DIGITAL TECHNOLOGIC ATTENUATE CONTROL CIRCUIT OF CURRENT-MODEL STEP BY STEP

摘要

The invention discloses a current mode step attenuation control circuit with digital technology. The circuit comprises: several stages of current attenuation circuit serially connected; the digital control input port, the common mode feedback signal input port and the bias input port are connected to corresponding a digital control signal, a common mode feedback current and a bias voltage, respectively. An analog input signal inputted to the circuit is controlled by the digital control signal to implement step attenuation. The circuit is original in conception. By using conducting resistance of MOS transistor to form equivalent resistance or match of current source for attenuation, the circuit eliminates dependence on resistance match of conventional technology. As step attenuation is directly controlled by digital control signal, so transmission speed is fast, phase delay is small, control accuracy is high and is also suitable for digital integrated circuit manufacturing technology.