US 2015/0319018 A1 · SLICER TRIM METHODOLOGY AND DEVICE

Abstract

Described embodiments provide for, in a receiver circuit employing a data latch, circuitry to adjust trim offset of the data latch to account for latch functional features (e.g., hysteresis and metastability) that may interact with trim of the latch. In accordance with the described embodiments, a trim procedure runs in a pre-selected directions of offset voltage ramp in order to average out the effect of hysteresis and metastability on the final trim offset choice. Different thresholds for accumulated slicer “0” and “1” discrimination of the circuitry to adjust trim offset allows for significant reduction in the number of trim runs, accelerating the slicers' trim process allowing for relatively quick determination of trim offset whenever the slicers are idle.

Claims20

Dependent claims

A method of generating a trim offset in a decision device, the method comprising:

applying a signal including a sequence of equivalent data values to the decision device;
initializing the trim offset value to a first trim value, the trim offset value applied to the decision device to set a decision threshold for the decision device;
varying the trim offset value over a range of trim values defined by a first trim value and a second trim value;
generating an inconclusive region by, for each of the trim values:
accumulating at least one output value of the decision device,
comparing the accumulated output value of the decision device to a high threshold and a low threshold, and
classifying, as conclusive or inconclusive, a current value of the trim offset value corresponding to each data value based on the comparison;
and
determining a desired trim offset value as the trim value about a center of the inconclusive region.

6 more elements

Apparatus for generating a trim offset, the apparatus comprising:

a decision device receiving a signal including a sequence of equivalent data values;
the logic circuitry configured to initialize the trim offset value to a first trim value, the trim offset value applied to the decision device to set a decision threshold for the decision device;
the logic circuitry configured to vary the trim offset value over a range of trim values defined by a first trim value to a second trim value;
the logic circuitry configured to generate an inconclusive region by, for each of the trim values:
accumulating at least one output value of the decision device,
comparing the accumulated output value of the decision device to a high threshold and a low threshold, and
classifying, as conclusive or inconclusive, a current value of the trim offset value corresponding to each data value based on the comparison;
and
the logic circuitry configured to determine a desired trim offset value as the trim offset value corresponding to the data value in the sequence about the center of the inconclusive region.

6 more elements

A non-transitory machine-readable storage medium, having encoded thereon program code, wherein, when the program code is executed by a machine, the machine implements a method for generating a trim offset in a decision device, comprising the steps of:

applying a signal including a sequence of equivalent data values to the decision device;
initializing the trim offset value to a first trim value, the trim offset value applied to the decision device to set a decision threshold for the decision device;
varying the trim offset value over a range of trim values defined by a first trim value and a second trim value;
generating an inconclusive region by, for each of the trim values:
accumulating at least one output value of the decision device,
comparing the accumulated output value of the decision device to a high threshold and a low threshold, and
classifying, as conclusive or inconclusive, a current value of the trim offset value corresponding to each data value based on the comparison;
and
determining a desired trim offset value as the trim value about a center of the inconclusive region.

6 more elements

Dependencies are inferred from the claim text.

Slicer trim methodology and device

Life of this patent

Slicer trim methodology and device

Life of this patent

Abstract

Claims20