1ED020I12-BT Datasheet, PDF (17/34 Pages) Infineon Technologies AG – Single IGBT Driver IC

EiceDRIVER™
1ED020I12-BT
Functional DescriptionMinimal On Time / Off Time
4.7
Minimal On Time / Off Time
The 1ED020I12-BT driver requires minimal on and off time for proper operation in the application. Minimal on time
must be greater than the adjustable two level plateau time T_TLSET, shorter on times will be suppressed by
generating of the plateau time refer to Figure 10. Due to the short on time, the voltage at TLSET pin does not
reach the comparator threshold; therefore the driver does not turn on. A similar principle takes place for off time.
Minimal off time must be greater than T_TLSET; shorter off times will be suppressed, which means OUT stays on
refer to Figure 11. A two level turn off plateau cannot be shortened by the driver. If the driver has entered the turn
off sequence it cannot switch off due to the fact, that the driver has already entered the shut off mode. But if the
driver input signal is turned on again, it will leave the lower level after T_TLSET time by switching OUT to high, refer
to Figure 12.
4.8
External Protection Features
4.8.1 Desaturation Protection
A desaturation protection ensures the protection of the IGBT at short circuit. When the DESAT voltage goes up
and reaches 9 V, the output is driven low, refer to Figure 9. Further, the /FLT output is activated. A programmable
blanking time is used to allow enough time for IGBT saturation. Blanking time is provided by a highly precise
internal current source and an external capacitor.
4.8.2 Active Miller Clamp
In a half bridge configuration the switched off IGBT tends to dynamically turn on during turn on phase of the
opposite IGBT. A Miller clamp allows sinking the Miller current across a low impedance path in this high dV/dt
situation. Therefore in many applications, the use of a negative supply voltage can be avoided.
During turn-off, the gate voltage is monitored and the clamp output is activated when the gate voltage goes below
typical 2 V (related to VEE2). The clamp is designed for a Miller current up to 2 A.
4.8.3 Short Circuit Clamping
During short circuit the IGBTs gate voltage tends to rise because of the feedback via the Miller capacitance. An
additional protection circuit connected to OUT and CLAMP limits this voltage to a value slightly higher than the
supply voltage. A current of maximum 500 mA for 10 μs may be fed back to the supply through one of this paths.
If higher currents are expected or a tighter clamping is desired external Schottky diodes may be added.
4.9
RESET
The reset input has two functions.
Firstly, /RST is in charge of setting back the /FLT output. If /RST is low longer than a given time, /FLT will be
cleared at the rising edge of /RST, refer to Figure 9; otherwise, it will remain unchanged. Moreover, it works as
enable/shutdown of the input logic, refer to Figure 7.
Final Data Sheet
17
Rev 2.0, 2012-07-31