2ED100E12-F_EVAL Infineon Technologies, 2ED100E12-F_EVAL Datasheet - Page 11

• Manufacturer Part Number: 2ED100E12-F_EVAL
• Description: Power Management IC Development Tools Eval Board EconoDual
• Manufacturer: Infineon Technologies

3.3
The IGBT switching frequency is limited by the available DC/DC power and by PCB temperature.
Accordingly to theory the power losses generated in gate resistors are a function of gate charge, voltage step
at the driver output and switching frequency. The energy is dissipated mainly through the PCB and increases
the temperature around the gate resistors. When the available power of the DC/DC is not reached, the
limiting factor for the IGBT’s switching frequency is the absolute maximum temperature for the FR4 material.
The temperature is105°C and shall not be exceeded.
Generally the power losses generated in the gate resistors can be calculated according to following formula
(1):
where:
P
f
The losses are shared between the internal – P(R
PCB temperature criteria the power of the external gate resistor P(R
thermal resistance is given.
Based on experimentally determined board temperature dependencies T
possible to determine the maximal IGBT switching frequency, if the power losses of the external gate resistor
and the max. ambient temperature are known.
As can be concluded from Figure 5, the board can dissipate approximately 0,29W from the external gate
resistors soldered to PCB at T
to increase the switching frequency up to 35kHz when the ambient temperature is decreased to 70°C. Under
these conditions the board can dissipate approximately 0,6W. At room temperature the 2ED100E12-F can
drive the IGBTs safely with the switching frequency limited by the available power of the DC/DC (1.5W).
Figure 5
Application Note
P
s
dis
dis
– switching frequency, Q
– dissipated power, ∆V
=
P
(
R
EXT
Maximum switching frequency
PCB temperature vs gate resistor power losses and switching frequency (FF225R12ME3)
)
+
P
(
R
INT
G
out
)
– IGBT gate charge (value given for a range of gate voltage level)
=
– voltage step at the driver output
a
=85°C. The max. switching frequency for this condition is 15kHz. It is possible
∆
V
out
⋅
f
s
⋅
Q
G
INT
11
) and the external - P(R
(1)
EXT
) is the interesting value when the
PCB
Driver for EconoDUAL
EXT
) gate resistors. Due to the
~ P(R
EXT
Application Note
) (Figure 5) it is
V1.0, 2006-05
AN2006-04
TM