2
\$\begingroup\$

I am trying to power a RPi of 4 AA's, and my mobile power device can only output limited current (500mA), but I can underpower my RPi by frequency scaling. Is frequency scaling and current draw a linear relationship?

\$\endgroup\$
4
\$\begingroup\$

Generally no. There will be some component of current draw that is linear, which represents the switching losses of the CMOS logic. But there also be various static (constant) loads as well, including such things as CMOS leakage current, the operating current for other components operating at a constant frequency, pullup resistors, etc.

\$\endgroup\$
  • \$\begingroup\$ So power is proportional to f, with some other current leakage added on? \$\endgroup\$ – Scott Apr 15 '13 at 20:31
  • \$\begingroup\$ There is probably a large number of factors, one being proportional to frequency, one being leakage current. Only way to find out is to do couple measurements averaged with various frequencies and then plot it in a graph. \$\endgroup\$ – jippie Apr 16 '13 at 6:44

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.