AN2123 STMicroelectronics, AN2123 Datasheet - Page 10

• Manufacturer Part Number: AN2123
• Description: TD351 Advanced IGBT Driver Principles of operation and application
• Manufacturer: STMicroelectronics

2-Level turn-off
Maximum voltage reached on the IGBT collector and commutation losses are shown in the charts of
Figure
over current (300 A) conditions.
It can be noted that in over-current conditions (see
significant reduction of Vcemax during turn-off. With LVoff values from 8 to 11 V, Vcemax is reduced from
1000 V to less than 750 V. The price to pay is an increase of the switching losses Eoff that are shifted
from 20 mJ to 30~40 mJ.
In normal conditions (see
wheter the 2-level turn-off feature is used or not, as long as LVoff is greater than 8.5 V.
These results suggest that it is useful to set the LVoff value from 9 to 10 V.
Figure 15. Influence of LVoff value on Vcemax and turn-off energy (IGBT Fuji 6MBI50S120L)
10/15
Tip:
1200
1000
800
600
400
200
15. The influence of the LVoff value is studied both for nominal rated current at 25°C (75 A) and
0
7
How does one disable the 2-level turn-off feature?
Connect LVOFF to VH, remove C
4.7 kΩ to 10 kΩ resistor.
over-current conditions: 400V/300A
8
9
Vce max 2-level
Vce max standard
Eoff 2-level
Eoff standard
Lvoff (V)
Figure
10
15, right graph) there is no noticeable difference to be seen regardless
11
12
60
50
40
30
20
10
0
d
capacitor and keep the CD pin connected to Vref by a
Figure
800
600
400
200
0
15, left graph) the 2-level turn-off can bring a
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8
normal conditions: 400V/75A
9
Vce max 2-level
Vce max standard
Eoff 2-level
Eoff standard
Lvoff (V)
10
11
12
AN2123
8.00
6.00
4.00
2.00
0.00