What is Dynamic power?

Power consumed in CMOS circuits charging and discharging capacitance when signals switch, expressed as αCV²f with activity factor α, capacitance C, voltage V and frequency f.

Field: Power Management

Dynamic power in the explanations

Questions that mention Dynamic power (12)

  1. In a CMOS circuit, if only the supply voltage is halved with everything else unchanged, what happens to dynamic power consumption?
  2. In the CMOS dynamic power formula P = αCV²f, what does α represent?
  3. What is the dynamic power of a circuit with activity factor α = 0.1, switched capacitance C = 1 nF, supply voltage V = 1 V and frequency f = 1 GHz?
  4. Assume DVFS can lower the supply voltage in proportion to frequency. When frequency is halved, roughly what happens to dynamic power and to the dynamic energy for a fixed amount of computation?
  5. If only the supply voltage is lowered by 10% (all else equal), by roughly what percentage does dynamic power fall?
  6. In a CMOS inverter, what is the current that flows from the supply to ground while the input is switching called?
  7. What is the main purpose of putting multiple processor cores on one chip (multicore)?
  8. Which technique reduces CPU power consumption by dynamically changing operating frequency and supply voltage according to the load?
  9. Which low-power design technique stops the clock to unused circuit blocks to reduce wasted power?
  10. With the supply voltage unchanged, only the clock frequency is halved. What happens to the dynamic energy needed to finish a fixed amount of computation?
  11. Which describes power gating?
  12. When does "race to idle" (finishing work fast and then sleeping deeply) tend to save energy?

Related terms

DVFS (dynamic voltage and frequency scaling) CMOS Activity factor Clock gating Power gating Static power Race to idle ACPI Adaptive voltage scaling (AVS) Break-even time

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