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US 6,617,887 B2Granted
Differential comparator with offset correction
AssigneeXilinx, Inc.
InventorMichael A. Nix
Life of this patent
Estimating the term…
Abstract
A differential comparator having offset correction and common mode control for providing stable op amp output that changes only due to the original inputs coming into the comparator. The difference comparator has increased common-mode difference tolerance, and large op-amp offset tolerance, as well as fast decision time.
Claims20
A differential comparator, comprising:
- an input stage;
- and
- an operational amplifier comprising a differential current mirror circuit to provide differential output currents, wherein the output currents are established in response to input signals, a common mode signal, and offset signals.
An analog to digital converter (ADC) comprising:
- a difference comparator comprising,
- a capacitively coupled input stage, and
- an operational amplifier comprising a differential current mirror circuit to provide differential output currents, wherein the output currents are established in response to input signals, a common mode signal, and offset signals;
- and
- a latch connected to an output of the difference comparator.
2 more elements
A difference comparator, comprising:
- first and second input branches each having two inputs to accept external input signals;
- and
- an offset corrected amplifier, each of the first and the second input branches connected to an input of the amplifier, wherein the amplifier inputs are selectively connectable to either a reference common mode voltage or to the first and second input branches.
A method of controlling a differential amplifier, comprising:
- adjusting output signals of the differential amplifier, during a zeroing phase, to have zero offset;
- and
- centering the output signals of the differential amplifier to the common mode signal, wherein adjusting and centering the output signals comprise adjusting a current mirror circuit of the differential amplifier.
Dependencies are inferred from the claim text.