MCU Power Budget Calculator

This tool estimates the current draw I_avg and I_peak of your microcontroller based on its operating state, clock frequency, and peripheral activity. It is essential for sizing batteries, choosing LDOs/Buck converters, and calculating expected runtimes for IoT devices.

Use this tool to:

• Estimate Average Current: Calculate the “weighted average” consumption based on your firmware’s duty cycle (Active vs. Sleep time).
• Identify Peak Bursts: Account for high-current events, such as WiFi/Bluetooth transmissions, which can cause significant voltage sags.
• Size Energy Storage: Determine if your battery capacity (mAh) is sufficient for your target deployment duration.

Key Input Parameters Explained

• Active Mode Time (%): This represents the “Duty Cycle” of your firmware. It is the percentage of time the MCU is awake and executing code versus the time it spends in a low-power sleep state.
• Clock Frequency (MHz): Power consumption scales with frequency. Lowering the clock speed reduces the dynamic power consumed by the internal logic gates.
• External Load Current (mA): This is the total current “sourced” by the MCU’s GPIO pins to power external components like LEDs, sensors, or transistors. This current is drawn directly from the MCU’s power supply.
• Battery Capacity (mAh): This value defines the total energy reservoir available. The calculator uses this to divide the total capacity by the average current draw to estimate total runtime.

Disclaimer: These results are theoretical estimates based on typical datasheet values. Actual power consumption may vary due to ambient temperature, component tolerances, firmware optimization, and specific I/O peripheral configurations. Always verify final power requirements with a multimeter or calibrated power profiler on your physical hardware before finalizing your design.

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