Amplifier networks with controlled common-mode level and converter systems for use therewith

An amplifier network to operate in first and second operational modes, comprising:

• a signal amplifier configured to process input signals to output signals centered about a common-mode level which is a function of a common-mode control signal;
• hold capacitors to hold said common-mode level;
• follower transistors inserted to provide isolation between said signal amplifier and said hold capacitors;
• refresh capacitors;
• refresh switches positioned to couple said refresh capacitors to receive charge from a common-mode reference voltage during said second operational mode;
• and
• transfer switches positioned to transfer charge from said refresh capacitors to said hold capacitors during said first operational mode to thereby generate said control signal.

A signal coverter system for converting analog input signals into corresponding digital codes, the system comprising:

• a pipelined arrangement of converter stages that successively process said input signals to corresponding digital bits;
• and
• an alignment/correction logic configured to process said digital bits into said digital codes wherein at least one of said stages includes a multiplying digital-to-analog coverter that provides a residue signal to a succeeding stage with the aid of an amplifier network that operates in first and second operational modes and includes:
• a signal amplifier configured to process input signals to output signals centered about a common-mode level which is a function of a common-mode control signal;
• hold capacitors to hold said common-mode level;
• follower transistors inserted to provide isolation between said signal amplifier and said hold capacitors;
• and
• a common-mode control structure arranged to control said common-mode level during first and second operational modes;
• wherein said control structure includes:
• a differential amplifier arranged to provide said control signal in response to the difference between said common-mode level and a common-mode reference voltage;
• and
• switches arranged to couple said differential amplifier to said common-mode level in said first operational mode and to isolate said differential amplifier in said second operational mode.

A signal coverter system for converting analog input signals into corresponding digital codes, the system comprising:

• a pipelined arrangement of coverter stages that successively process said input signals to corresponding digital bits;
• and
• an alignment/correction logic configured to process said digital bits into said digital codes wherein at least one of said stages includes a multiplying digital-to-analog coverter that provides a residue signal to a succeeding stage with the aid of an amplifier network that operates in first and second operational modes and includes:
• a signal amplifier configured to process input signals to output signals centered about a common-mode level which is a function of a common-mode control signal;
• hold capacitors to hold said common-mode level;
• follower transistors inserted to provide isolation between said signal amplifier and said hold capacitors;
• and
• a common-mode control structure arranged to control said common-mode level during first and second operational modes;
• wherein said control structure includes:
• refresh capacitors;
• refresh switches positioned to couple said refresh capacitors to receive charge from a common-mode reference voltage during said first operational mode;
• and
• transfer switches positioned to transfer charge from said refresh capacitors to said hold capacitors during a second one of said operational modes to thereby generate said control signal.