Calculadora de Potência do MOSFET
Calcule a dissipação de potência em transistores MOSFET durante condução e chaveamento.
Conduction Loss
1.250 W
Conduction Loss vs On-Resistance (Rds_on)
Formula
## MOSFET Power Losses ### Conduction Loss **P_cond = Rds(on) x I_D^2** ### Switching Loss **P_sw = 0.5 x V_DS x I_D x (t_rise + t_fall) x f_sw** Total loss is the sum. Conduction loss dominates at low frequencies; switching loss dominates at high frequencies.
Exemplo Resolvido
MOSFET with 50 mohm Rds(on), 5 A load, switching 12 V at 100 kHz with 50 ns transitions.
- 01Conduction = 0.05 x 25 = 1.25 W
- 02Switching = 0.5 x 12 x 5 x 50e-9 x 100000 = 0.15 W
- 03Total = 1.25 + 0.15 = 1.40 W
Perguntas Frequentes
Does Rds(on) change with temperature?
Yes, Rds(on) increases with temperature, roughly doubling from 25C to 150C for silicon MOSFETs.
How to reduce switching losses?
Use a gate driver for faster switching, choose MOSFETs with low gate charge, or reduce switching frequency.
What about gate drive losses?
Gate charge losses (P = Qg x Vgs x f) are usually small but matter at very high frequencies.
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