Circuit for controlling a linear-in-decibels attenuator circuit using an analog control signal

An analog controlled linear-in-decibels digital attenuator circuit, comprising:

• a resistive ladder circuit comprising:
• a plurality of series resistances coupled in series between an input electrode for conveying an input signal and an output electrode for conveying an output signal;
• and
• a plurality of shunt resistances each of which is coupled to a corresponding series resistance of said plurality of series resistances and to a corresponding digitally controlled switch;
• a plurality of digitally controlled switches each of which is controlled by a corresponding digital control signal, wherein each of said plurality of digitally controlled switches comprises:
• a pole electrode coupled to a respective one of said plurality of shunt resistances and to said input electrode;
• and
• a throw electrode coupled to a respective one of said plurality of shunt resistances and to a common node for attenuating voltage from said input signal;
• and
• a flash analog-to-digital converter controlled by an analog control signal for providing a plurality of digital control signals each of which is coupled to and for controlling a corresponding digitally controlled switch.

An apparatus including an integrated digitally controlled linear-in-decibels attenuator circuit, comprising:

• a plurality of attenuation control electrodes to convey a plurality of digital control signals corresponding to a signal attenuation value;
• an input signal electrode to convey an input signal;
• an output signal electrode to convey an output signal corresponding to said input signal and having a magnitude which is less than an input signal magnitude of said input signal in relation to said signal attenuation value;
• a resistive ladder circuit including a plurality of series resistances coupled in series between said input and output signal electrodes, and a plurality of shunt resistances each of which is coupled in shunt to a corresponding series resistance of said plurality of series resistances;
• a plurality of switch circuits, each of which comprises:
• a pole electrode coupled to a respective one of said plurality of shunt resistances and to said input electrode;
• and
• a throw electrode coupled to a respective one of said plurality of shunt resistances and to said common node for attenuating voltage from said input signal;
• and
• a flash analog-to-digital converter controlled by an analog control signal for providing said plurality of digital control signals each of which is coupled to and for controlling a corresponding digitally controlled switch.