Power dissipation due to OUTPUT slewing during FET turn ON in the recirculation path is given by:PSW3 [W] = (0.5 x VD x IL x VD / SRrise x fPWM) + (0.5 x VD x IL x VD / SRfall x fPWM), where, (4)i. fPWM = PWM switching frequency [Hz]ii. VD = FET body diode forward bias voltage [V]iii. IL = Load current [A]iv. SRrise = Output voltage slew rate during rise [V/sec]v. SRfall = Output voltage slew rate during fall [V/sec]This dissipation is typically not considered as it is quite insignificant.

Power dissipation due to the dead times between switching FETs is given by:PSW2 [W] = (VD x IL x tDEADrisex fPWM) + (VD x IL x tDEADfallx fPWM), where, (3)i. fPWM = PWM switching frequency [Hz]ii. VD = FET body diode forward bias voltage [V]iii. IL = Load current [A]iv. tDEADrise = dead time during rise [sec]v. tDEADfall = dead time during fall [sec]Dead times are necessary to mitigate any risk of current shoot through between the switching powerFETs. Integrated FET drivers often have a feedback based self timed FET switching sequence to ensurethe smallest possible dead times while avoiding any shoot through current.

Power dissipation from conduction loss of each FET due to its on-resistance is given by:PRON [W] = RON × IL2, where, (1)a. RON = FET on-resistance [ohm]b. IL = Load current [A]

Power dissipation due to output slewing during rising and falling edges is given by:PSW1 [W] = (0.5 x VM x IL x VM / SRrise x fPWM) + (0.5 x VM x IL x VM / SRfall x fPWM), where, (2)i. fPWM = PWM switching frequency [Hz]ii. VM = Supply voltage to the driver [V]iii. IL = Load current [A]iv. SRrise = Output voltage slew rate during rise [V/sec]v. SRfall = Output voltage slew rate during fall [V/sec]Output slewing rate is a balance between EM (Electro magnetic) performance and device powerdissipation.