Sandisk Technologies Inc.

Advanced Micro Devices Corporation

Bhawna Tomar

Arun Sundaresan Iyer

Animesh Jain

Ajay Kanth Chitturi

Krishna Sethupathy Leela

Murali Krishna Balaga

A circuit may perform a skew correction process that positions clock pulses of an output clock signal in respective target sampling positions. The circuit may receive an input clock signal and an input data signal and select one of a plurality of predetermined skew cases for the input clock signal and the input data signal. In addition, the circuit may performing timing relationship measurements for transition permutations of the clock signal and the data signal. The circuit may determine which of the input clock signal and the input data signal to delay and an amount of the delay based on the selected skew case and the timing relationship measurements. An output of the circuit may delay the input clock signal or the input data signal according to the determinations, which centers the sampling transitions of the clock signal in target sampling positions.

Skew correction for source synchronous systems

A circuit may include control circuitry configured to determine a duty cycle error for a sample clock signal. Based on the duty cycle error the control circuitry may determine a corrective direction by which to alter the duty cycle to correct the duty cycle error. The control circuitry may indicate the corrective direction to selection circuitry via a selection signal. Responsive to the selection signal, the selection circuitry may select a leading phase signal and a lagging phase signal from among a plurality of relative phase signals. Output circuitry may combine the leading phase signal and a lagging phase signal to generate an output clock signal with a duty cycle corresponding the corrective direction.

Duty cycle correction scheme

Embodiments of systems and methods are described for reducing the effects of hysteresis in the operation of data processing circuitry. In this embodiment of the invention, adaptive control circuitry is used to reduce the effects of hysteresis. The embodiment disclosed herein provides significant reduction in the effects of hysteresis and, therefore, a significant reduction in the amount of guard band needed to compensate for hysteresis effects in SOI processes and thereby improving the performance/power characteristics of the circuit.

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Bhawna Tomar