6.5.2. Power Consumption

Try these first

1. 1.

   What is static power consumption in CMOS?

   Hint

   Think about when the circuit is not actively changing state.

2. 2.

   What does dynamic power consumption depend on?

   Hint

   Remember the formula P=αCV²f.

3. 3.

   What is the formula for dynamic power consumption in CMOS?

   Hint

   Remember the terms we correlated with each variable.

4. 4.

   True or False: Static power consumption in a CMOS circuit is usually higher than dynamic power consumption.

   • True
   • False

   Hint

   Consider when each type of power consumption occurs.

5. 5.

   Consider a CMOS device with a capacitance of 10pF, operating at 2V, and switching at a frequency of 500kHz with a switching activity of 0.5. Calculate its dynamic power consumption.

   Hint

   Follow the formula closely and make sure to calculate in the correct units.

6. 6.

   How would the dynamic power consumption change if the switching frequency of the circuit is increased to 1 MHz while keeping everything else constant? Explain.

   Hint

   Look closely at the factors within the dynamic power formula.