n-bit analog-to-digital converter with n-1 magnitude amplifiers and n comparators

A magnitude amplifier (magamp) for receiving a differential analog input and for providing an amplified signal at a first output and a second output, the magamp comprising:

• a first unit including:
• a first differential input circuit for receiving and amplifying the differential analog input,
• a current switching circuit, coupled to the first differential input circuit, for folding the differential analog input at a predetermined relationship between first and second signals of the differential analog input and for providing first and second folded signals,
• a comparator for receiving the differential analog input and for generating first and second control signals based on a comparison of the first and second signals of the differential analog input, the first and second control signals controlling the current switching circuit, and
• first and second output means connected to the current switching circuit for receiving the first and second folded signals, respectively, and for providing first and second output signals;
• and
• a second unit including:
• a second differential input circuit for receiving and amplifying a differential reference signal and for providing an offset current to the first unit to align the first and second folded signals such that a magnitude of one of the first and second folded signals is altered relative to the other, and
• third and fourth output means connected to the second differential input circuit for providing third and fourth output signals.

A magnitude amplifier (magamp) comprising:

• a first unit including:
• a first differential input circuit for receiving and amplifying a differential analog input,
• a current switching circuit, connected to the first differential input circuit, for folding first and second signals of the differential analog input at a predetermined relationship between the signals of the differential analog input to provide first and second folded signals,
• a comparator for receiving the differential analog input and generating first and second control signals based on a comparison of the first and second signals of the differential analog input, the first and second control signals controlling the current switching circuit, and
• first and second output nodes that connect to the current switching circuit;
• and
• a second unit including:
• a second differential input circuit for receiving and amplifying a differential reference voltage and for providing offset current to align the first and second folded signals and for setting a full-scale input voltage range for the magamp, and
• third and fourth output nodes that connect to the second differential input circuit.

An amplifier for receiving a differential analog input and for providing an output at first and second outputs, the amplifier comprising:

• a differential input circuit for receiving the differential analog input;
• a comparator for receiving the differential analog input and for providing first and second control signals;
• a current switching circuit connected to the differential input circuit for folding the differential analog input in response to the first and second control signals;
• a first transistor connected on a first side to the current switching circuit and on a second side to the first output;
• a second transistor connected on a first side to the current switching circuit and on a second side to the second output;
• and
• a reference circuit coupled to control terminals of the first and second transistors for providing bias voltages thereto.

An amplifier for receiving a differential analog input and for providing an output at first and second outputs, the amplifier comprising:

• a differential input circuit for receiving the differential analog input;
• a comparator for receiving the differential analog input and for providing first and second control signals;
• a current switching circuit connected to the differential input circuit for folding the differential analog input in response to the first and second control signals;
• a first transistor connected on a first side to the current switching circuit and on a second side to the first output;
• a second transistor connected on a first side to the current switching circuit and on a second side to the second output;
• and
• first and second output transistors, each having a control input coupled to the second side of the respective first and second transistors.

An amplifier for receiving a differential analog input and for providing an output at first and second outputs, the amplifier comprising:

• a differential input circuit for receiving the differential analog input;
• a comparator for receiving the differential analog input and for providing first and second control signals;
• a current switching circuit connected to the differential input circuit for folding the differential analog input in response to the first and second control signals;
• a first cascode transistor connected on a first side to the current switching circuit and on a second side to the first output;
• and
• a second cascode transistor connected on a first side to the current switching circuit and on a second side to the second output;
• wherein the first and second cascode transistors are pnp transistors having emitters connected to the current switching circuit and collectors coupled to the respective first and second outputs.

An amplifier system having a plurality of connected stages, each of the stages comprising:

• an amplifier unit including:
• a differential input circuit for receiving a respective differential analog input signal,
• a comparator for receiving the respective differential analog input signal and for generating first and second control signals based on a relationship of the respective differential analog input signal,
• a current switching circuit connected to the differential input circuit for folding the respective differential analog input signal in response to the first and second control signals, and
• first and second output circuits connected to the current switching circuit for providing respective first and second output signals to a next stage;
• and
• a reference unit including:
• a second differential input circuit for receiving a respective differential reference signal, for providing an offset signal to align the first and second output signals, and for providing to the next stage a differential reference output signal.