National Yang Ming Chiao Tung University

Chung-Ying Hsieh

Wei Hwang

Ming-Hung Chang

A method buffers clock skew by using a logical effort, and is applicable to a clock tree that stays in a strong-inversion region, a moderate-inversion region, or a weak-inversion region. The method includes establishing in the clock tree a temperature sensor and a tunable-width buffer, and establishing width and temperature comparative lists according to a logical effort equation, for the tunable-width buffer to be individually applied to the strong-inversion region, the moderate-inversion region, and the weak-inversion region; selecting one from the width and temperature comparative lists that corresponds to one of the inversion regions in which the clock tree stays, enabling the temperature sensor to sense a temperature, and searching the selected width and temperature comparative list for a width that corresponds to the temperature sensed by the temperature sensor; and enabling the tunable-width buffer to perform a width modulation process according to the searched width.

Method for buffering clock skew by using a logical effort

A programmable clock generator, which is used in dynamic-voltage-and-frequency-scaling (DVFS) operated in Sub- and Near-Threshold region. The programmable clock generator includes first pulse generating unit and a pulse multiplier. A first counter is configured to generate a first counting signal, so as to control the phase detector comparing the phase difference between a first pulse signal and a second pulse signal. A first control signal is transmitted by a control unit in accordance with a phase difference signal, and the phase of the second pulse signal is adjusted by a lock-in delay unit, so that a predetermined phase is generated between the first pulse signal and the second pulse signal. The PVT variation may be compensated by the programmable clock generator during the sub threshold region. Therefore, the period of reference clock is in the locking range of lock-in delay line.

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Hsinchu, Taiwan

Chung-Ying Hsieh