1. What is Short-Circuit Power in CMOS?

Short-Circuit Power is defined as the theoretical current that will run in the event of a short circuit if the protection has not yet intervened. In CMOS circuits, it represents the power dissipation that occurs during the brief period when both NMOS and PMOS transistors are partially on during switching transitions.

2. How Does the Calculator Work?

The calculator uses the Short-Circuit Power formula:

Where:

• \( P_{sc} \) — Short-Circuit Power (Watt)
• \( P_{dyn} \) — Dynamic Power (Watt)
• \( P_s \) — Switching Power (Watt)

Explanation: The short-circuit power is calculated by subtracting the switching power from the total dynamic power, representing the portion of power dissipated during the short-circuit current flow in CMOS gates.

3. Importance of Short-Circuit Power Calculation

Details: Accurate short-circuit power calculation is crucial for CMOS circuit design, power optimization, thermal management, and overall system reliability. It helps designers minimize unnecessary power dissipation and improve energy efficiency.

4. Using the Calculator

Tips: Enter dynamic power and switching power values in watts. Both values must be non-negative numbers. The calculator will compute the short-circuit power by subtracting switching power from dynamic power.

5. Frequently Asked Questions (FAQ)

Q1: What causes short-circuit power in CMOS circuits?
A: Short-circuit power occurs during the brief period when both pull-up and pull-down networks are partially conducting during signal transitions, creating a direct current path from VDD to GND.

Q2: How can short-circuit power be minimized?
A: Short-circuit power can be minimized by using balanced rise and fall times, proper transistor sizing, and avoiding very sharp input signal transitions.

Q3: What percentage of total power does short-circuit power typically represent?
A: In well-designed CMOS circuits, short-circuit power typically represents 5-15% of the total dynamic power, though this can vary based on design parameters and operating conditions.

Q4: Does short-circuit power depend on operating frequency?
A: Yes, short-circuit power is frequency-dependent as it occurs during each switching event, so higher operating frequencies result in more frequent short-circuit current flow.

Q5: How does supply voltage affect short-circuit power?
A: Short-circuit power generally increases with higher supply voltages, as the current during the short-circuit period is proportional to the voltage difference between supply rails.