Switching Regulator Efficiency Calculator
Calculate the input power and current draw of a switching regulator given output requirements and efficiency.
V
V
A
%
Input Power
7.33 W
Input Current0.611 A
Power Lost0.73 W
Input Power vs Input Voltage
Switching Regulator Efficiency
Formulas
P_in = P_out / Efficiency
I_in = P_out / (Efficiency x V_in)
Switching regulators convert voltage using rapid switching and an inductor. They achieve 85-95% efficiency regardless of voltage ratio, far better than linear regulators for large step-downs.
Example Calculation
12 V to 3.3 V at 2 A with 90% efficiency.
- 01P_out = 3.3 x 2 = 6.6 W
- 02P_in = 6.6 / 0.9 = 7.33 W
- 03I_in = 7.33 / 12 = 0.611 A
- 04Power lost = 7.33 - 6.6 = 0.73 W
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