Dynamic vs static summary.

Dynamic vs static summary.

• A. Dynamic power occurs during idle time.
• B. Static power is related to switching activity.
• C. Dynamic power arises from charging/discharging capacitances during switching and scales with f, C, V^2.
• D. Static power is independent of leakage.

Answer: (C)

In circuits, there are two main ways power is used: dynamic power and static power. Dynamic power comes from charging and discharging the load capacitances every time the transistors switch. The energy used per transition is about 1/2 C_L V^2, so the total dynamic power scales with how often switching happens, the capacitance involved, and the square of the supply voltage. Put simply, more switches per second, larger capacitances, or higher voltage means more dynamic power. Static power, on the other hand, comes from leakage currents that flow even when no switching occurs. This leakage current times the supply voltage gives static power, and it does not depend on how often the circuit is switching. It depends on device leakage, geometry, and conditions like temperature. So the best description among the choices is the one that says dynamic power arises from charging and discharging capacitances during switching and scales with switching frequency, capacitance, and V^2. The other statements mix up when dynamic power occurs or misstate the role of leakage in static power.

In circuits, there are two main ways power is used: dynamic power and static power. Dynamic power comes from charging and discharging the load capacitances every time the transistors switch. The energy used per transition is about 1/2 C_L V^2, so the total dynamic power scales with how often switching happens, the capacitance involved, and the square of the supply voltage. Put simply, more switches per second, larger capacitances, or higher voltage means more dynamic power.

Static power, on the other hand, comes from leakage currents that flow even when no switching occurs. This leakage current times the supply voltage gives static power, and it does not depend on how often the circuit is switching. It depends on device leakage, geometry, and conditions like temperature.

So the best description among the choices is the one that says dynamic power arises from charging and discharging capacitances during switching and scales with switching frequency, capacitance, and V^2. The other statements mix up when dynamic power occurs or misstate the role of leakage in static power.