6ED family - 2nd generation
Technical Description
Application Note 18 Rev. 1.3, 2014-03-23
AN-EICEDRIVER-6EDL04-1
The maximum chip temperature T
j
can be calculated with
where T
amb, max
is the maximum ambient temperature.
The dissipated power P
d
is a combination of several sources. The following items contribute to the total power
dissipation:
- the quiescent current (high side and low side) of the IC (P
d1VCC
, P
d1BS
)
- the output section (P
d2on
, P
d2off
)
- the input sections of the IC (P
d3
)
- the leakage losses between any high side section to the control section (P
d4
)
The individual items can be calculated for a worst case by means of the following cooking recipie:
1. Measure the operating current I
CC
for maximum switching frequency of the application. Connect all three high
side control pins and low side control pins and do not connect power transistors.
Each high side section generates a continuous power dissipation in respect of the quiescent current. This is
given as
2. Calculate the losses of the output section by means of the total gate charge of the power transistor Q
Gtot
, the
supply voltage V
CC
, the switching frequency f
P
,and the ext. gate resistor. Different cases for turn-on and turn-off
must be considered, because many designs use different resistors for turn-on and turn-off. This leads to a
specific distribution of losses in respect to the external gate resistor R
Gxx,ext
and the internal resistance of the
output section.
Both portions P
d2on
and P
d2on
together are the output section losses.
3. The input sections generate losses by means of their input structures. These are either pull down resistors
(types: 6EDL04I06PT,6EDL04N06PT, 6EDL04N02PR) or pull up resistor (types: 6EDL04I06NT, 6ED003L06-F2
/ 6ED003L02-F2). A duty cycle of 50% is considered:
4. The leakage losses are given by the current, which crosses the insulation barrier. The relevant parameters
are the leakage current I
LVS
of any high side and the DC bus voltage V
DC
of the application. The high side
section is either on the positive bus potential or at the negative bus potential during operation. It is therefore in
principle half the product of these two values. However, there can be a static status of operation, where all three
high side sections are on high potential. Thus, we get
All remaining contributions ban be estimated as approximately 20% of the sum of the above mentioned
portions. The final power dissipation during operation is then the sum of both contributions
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