| 摘要 |
Integrated circuit output buffers include an integrated circuit substrate, an output buffer in the substrate which drives a respective load, an supplemental voltage supply pad on the substrate, a first switch and at least one external capacitor which is electrically coupled to the supplemental voltage supply pad. The first switch is electrically coupled in series between an output of the output buffer and the supplemental voltage supply pad. During operation, the first switch is closed to facilitate the forward transfer of stored charge from the at least one external capacitor (e.g., 1 muF) to a capacitive load (e.g., 100 pF) during a first portion of a pull-up time interval. The output buffer is then turned on to complete the pull-up operation. Next, the transferred charge is recycled back from the load into the external capacitor by closing the first switch again during a first portion of a pull-down time interval. The output buffer is then turned on to complete the pull-down operation. By recycling at least some of the charge used to drive the capacitive load, the amount of current required by the output buffer during a complete pull-up/pull-down cycle can be reduced.
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