Power Supply Sizing & Derating Calculator

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DEW Power Tools

Power Supply Sizing & Derating

Example datasheet values

Your load

Output voltage (V)

Continuous load current (A)

Peak load current (0 = none) (A)

Peak duration (s)

Peak duty cycle (%)

Design margin (%)

Where it runs

Ambient around the supply (°C)

AC input

Supply (from its datasheet)

Rated output voltage (V)

Rated output current (A)

Maximum output power (W)

Peak current rating (0 = none) (A)

Peak time limit (s)

Peak duty limit (%)

Adjust range, low (V)

Adjust range, high (V)

Full load up to (°C)

Maximum operating (°C)

Load allowed at maximum (%)

Minimum operating (°C)

Efficiency at 100 VAC (%)

Efficiency at 200 VAC (%)

Power factor at 100 VAC

Power factor at 200 VAC

Peak rating applies at

Readout

POWER AVAILABLE AT YOUR AMBIENT

—W

CONTINUOUS LOAD AS A SHARE OF IT

—%

RATING TO SPECIFY (WITH MARGIN)

—W

AC INPUT CURRENT AT THIS LOAD

—A

CHECKS

—

Derating is taken as a straight line between the datasheet points (full load up to the knee, the stated percentage at the maximum operating temperature). Check the curve and mounting orientation in the datasheet. Peak ratings are taken as stated; ask the maker how they derate with temperature.