求助lib中的internal power的具体定义
有点忘记了,好像是包含的
工具报出的power包含三部分:internal power,switch power,leakage power。
internal power是指cell本身的功耗,其包含短路功耗和翻转功耗;
switch power是指wire上的翻转功耗。
个人理解
internal power是当输入发生变化输出保持不变时cell内部发生的功耗,因为输出不变,所以internal功耗都写在发生跳变的输入pin下
小编,这个问题好像是两种都有的,就是有的lib里面的internal只包含短路电流功耗,有的lib里面包含了短路电流功耗和cell的翻转功耗。ptpx中有这样一个命令 power_table_include_switching_power 默认情况是true就是说包含了cell内部的翻转功耗。详细可见ptpx ug 区别的方法文中如是说:
“The best way of finding out the formula used in the characterization is to consult the library
vendor. A workaround is to inspect the falling power tables. If most of them have negative
numbers, it is likely that formulas 1 and 2 are used in characterization.”
但是我有个问题,还请小编赐教:
internal power 在lib中记录的是energy (焦耳) 还是power (瓦特) ? 感觉synopsys文档中有混淆, 如果是请告诉单位,谢谢
小编,能解答一下我的问题吗?
“Internal power in the Liberty (.lib) format refers to the amount of energy
consumed by a cell during a switching event,” 来自SILICONSMART的UG,
The unit for switching power and internal power is a derived unit. It is derived from the
following function:
(capacitive_load_unit voltage_unit^2) ⁄ time_unit
来自Library Compiler Modeling Timing, Signal Integrity, and Power in Technology Libraries User Guide
换算到标准量纲是mJ