Dynamic slew rate controlling method and device for reducing variance in simultaneous switching output
AssigneeALi Corporation
InventorChun-Wen Yeh
Life of this patent
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Abstract
A dynamic slew rate controlling method and a device is provided to reduce SSO variance generated from voltage noises, which is as a result of a plurality of data bits switching to the same state simultaneously while the I/O bus transmits these data bits. The device and method at first analyzes data patterns, then determines the slew rate controlling setting value based on the slew rate controlling mapping table corresponding to different data patterns, and then transmits the setting value to the I/O buffer with the same voltage level in order to reduce the SSO variance.
Claims11
A dynamic slew rate controlling device for reducing the variance in simultaneous switching output (SSO), in which the SSO variance is reduced by analyzing a data pattern and controlling the slew rate of the data bits when different data bits are converted in order to dynamically adjust the driving capability of an input/output buffer (I/O buffer), the controlling device comprises:
- a data pattern detecting unit for detecting the switching signals of the inputted data bits;
- a calculating unit electrically connected to the data pattern detecting unit for receiving outputs of the data pattern detecting unit;
- a slew rate controlling mapping table electrically connected to the calculating unit for receiving outputs thereof;
- a slew rate controlling bus connected to the slew rate controlling mapping table for receiving outputs thereof;
- and
- a slew rate controlling unit located within the I/O buffer for connecting the slew rate controlling bus and receiving outputs thereof.
A dynamic slew rate controlling method for reducing the variance in simultaneous switching output (SSO), which is used to modify slew rates by analyzing data patterns of data bits and dynamically adjusting the driving capability of an input/output buffer (I/O buffer) in order to compensate the slew rates of the data bits, the method comprises:
- receiving the switching signals of the data bits by a data pattern detecting unit;
- analyzing the data pattern of the switching signals of the data bits in order to determine whether the switching signal is a rising or descending signal;
- operating the calculation;
- determining a slew rate setting value with respect to a slew rate controlling mapping table;
- and
- adjusting the slew rate.
Dependencies are inferred from the claim text.