MSK4853 M. S Kennedy, MSK4853 Datasheet - Page 3

• Manufacturer Part Number: MSK4853
• Description: 600v/200a Three Phase Bridge Pem With Brake
• Manufacturer: M. S Kennedy

THERMAL CALCULATIONS
PWM duty cycle and switching frequency all factor into power dissipation. DC losses or "ON-TIME" losses are simply
V
duty cycle of 30%, DC losses equal TBD watts. Switching losses, in milli-joules, vary proportionally with switching fre-
quency. The MSK 4853 typical switching losses at V
of the turn-on switching loss and the turn-off switching loss. Multiplying the switching frequency times the switching
losses will result in a power dissipation number for switching. The MSK 4853, at 15KHz, will exhibit switching power
dissipation of TBD watts. The total losses are the sum of DC losses plus switching losses, or in this case, TBD watts total.
TBD watts x 0.19°C/W thermal resistance equals TBD degrees of temperature rise between the case and the junction.
Subtracting TBD°C from the maximum junction temperature of 150°C equals TBD°C maximum case temperature for this
example.
CE
Power dissipation and maximum allowable temperature rise involve many variables working together. Collector current,
Turn-on switching loss + Turn-off switching loss = Total switching losses = TBD + TBD = TBDmJ
Total switching loss x PWM frequency = Total switching power dissipation = TBDmJ x 15KHz = TBD watts
Junction temperature rise above case = Total power dissipation x thermal resistance
Maximum junction temperature - junction temperature rise = maximum baseplate temperature
V
Total power dissipation = DC losses + switching losses = TBD + TBD = TBD watts
APPLICATION NOTES
(SAT) x Collector Current x PWM duty cycle. For the MSK 4853, V
CE
150°C - TBD°C = TBD°C
TBD watts x TBD°C/W = TBD°C temperature rise above case
(SAT) x IC x PWM duty cycle = TBDV x 200 amps x 30% = TBD watts DC losses
CE
=300V and I
3
CE
=200A are about TBDmJ, which is simply the sum
CE
(SAT)=TBD max., and at 200 amps and a PWM
PRELIMINARY Rev. A
10/10