Comparator operable with low power supply voltage
AssigneeNEC Corporation
InventorHiroshi Hasegawa
Life of this patent
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Abstract
A comparator includes a sampling section for respectively obtaining first and second voltage signals from first and second target voltage signals. An amplifier section includes first and second amplifiers and amplifies the obtained first and second voltage signals by the first and second amplifiers, respectively. A shifting section shifts the obtained first and second voltage signals into predetermined operation ranges of the first and second amplifiers in voltage level, respectively. A latching section latches outputs of the first and second amplifiers to output data determined based on the first and second voltage signals.
Claims30
A comparator comprising:
- sampling means for obtaining first and second voltage signals from first and second target voltage signals respectively;
- amplifier means including first and second amplifiers, for amplifying shifted obtained first and second voltage signals by said first and second amplifiers, respectively;
- shifting means coupled between said sampling means and said amplifier means for shifting said obtained first and second voltage signals into predetermined operation ranges of said first and second amplifiers in respectively;
- and
- latching means for latching outputs of said first and second amplifiers to output data determined based on said first and second voltage signals.
A method of outputting binary data corresponding to two voltage signals, comprising the steps of:
- sampling first and second target voltage signals to produce first and second voltage signals in first and second periods, respectively;
- shifting said sampled first and second voltage signals into a predetermined operation range of amplifier means in a third period, respectively;
- amplifying shifted first and second voltage signals by said amplifiers means in said third period;
- and
- latching outputs of said amplifier means to output a binary data determined based on said first and second voltage signals in said third period.
A comparator comprising:
- first to fourth capacitors;
- bias means coupled between one terminal of said first capacitor and one terminal of said third capacitor and between one terminal of said second capacitor and one terminal of said fourth capacitor, for selectively setting said first to fourth capacitors to a predetermined voltage;
- voltage applying means connected to the other terminals of said third and fourth capacitors, for applying a shift voltage to the other terminals of said third and fourth capacitors to change voltages at the one terminals of said third and fourth capacitors;
- amplifier means for amplifying the changed voltages at the one terminals of said third and fourth capacitors;
- and
- data latch means coupled to the amplifier means for outputting a data corresponding to voltage signals supplied to the other terminals of said first and second capacitors.
Dependencies are inferred from the claim text.