Electronic – Relationship between I2C drawn energy / power consumption and data rate


Referring to just what the I2C lines draw, am I wrong thinking that the higher the clock frequency the shorter the time there will be (the same amount of) current flowing through the pullups and thus lower power consumed?

side qeustion

I don't think I am going to reach 100 kHz, that's way over the limit of my hardware. I am alternating between about 32 and 4 kHz. Will the same resistor value (3.3k @ 3V) be good for both?

Best Answer

Higher clock frequency usually require lower pull-up value, thus increasing the current.

Increasing the clock frequency from 100kHz to 400kHz usually requires the pull-up to be reduced with a factor of 4-5.

Since the power is inverse proportional to the resistance the power consumed will be almost the same.