System power budget calculator
Interactive engineering and procurement calculator. Instant client-side computation with no sign-up.
Loads
0.495 W
Supply & battery
Power budget
3.3 V rail
current and power on this rail
Total power
Σ V·I across all loads
Bus current @ 5 V
total power ÷ (bus voltage × efficiency)
Battery life
capacity ÷ bus current — constant draw assumed
About the model
Every rail has a power budget and a thermal one — the amps you draw are I²R losses you have to get rid of somewhere. On a single bus, current is total power ÷ (bus voltage × efficiency), so a 12 V bus draws a quarter of the current of a 3 V bus at the same power. Battery life here assumes a constant draw: real MCUs pulse between sleep and active, so use the average current, not the peak.
Keeping rails honest? Check your voltage regulators and batteries in the catalog.
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