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US 7,030,804 B2Granted
Switched-capacitor circuit and pipelined A/D converter
AssigneeFujitsu Limited
InventorsMasato Yoshioka, Masahiro Kudo
Life of this patent
Estimating the term…
Abstract
An input capacitor and a plurality of reference capacitors sample an input voltage and reference voltages in a first period. A switch circuit connects the input capacitor and one of the reference capacitors between an output and an input of an amplifier in a second period. This mechanism causes a feedback gain to be “1” in the second period. Therefore, it is possible to reduce power consumption and noise.
Claims16
A switched-capacitor circuit comprising:
- an input capacitor and first to nth reference capacitors (n is an integer equal to or larger than 2) sampling an input voltage and first to nth reference voltages, respectively, in a first period;
- an amplifier generating an output voltage corresponding to the input voltage in a second period subsequent to the first period;
- and
- a switch circuit that, in the second period, connects said input capacitor between an output and an input of said amplifier and connects at least one of said first to nth reference capacitors between the output and the input of said amplifier according to a control signal.
1 more element
A pipelined A/D converter comprising:
- a plurality of stages connected in cascade, converting an analog voltage to a digital value in sequence from a higher-order digit, wherein:
- at least one of said stages has a switched-capacitor circuit;
- and
- the switched-capacitor circuit includes:
- an input capacitor and first to nth reference capacitors (n is an integer equal to or larger than 2) sampling an input voltage and first to nth reference voltages, respectively, in a first period;
- an amplifier generating an output voltage corresponding to the input voltage in a second period subsequent to the first period;
- and
- a switch circuit that, in the second period, connects said input capacitor between an output and an input of said amplifier and connects at least one of said first to nth reference capacitors between the output and the input of said amplifier according to a control signal.
5 more elements
Dependencies are inferred from the claim text.