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1EDI2001AS_15 Datasheet, PDF (55/135 Pages) Infineon Technologies AG – Single Channel Isolated Driver for Inverter Systems AD Step
3.2
Protection Functions: Category A
EiceDRIVER™ SIL
1EDI2001AS
Protection and Diagnostics
3.2.1
Desaturation Protection
The integrated desaturation (DESAT) functionality is summarized in Table 3-2:
Table 3-2 DESAT Protection Overview
Parameter
Short Description
Function
Periodicity
Monitoring of the VCE voltage of the IGBT.
Continuous while device issues a PWM ON command.
Action in case of failure event 1. Emergency (Safe) Turn-off Sequence.
2. Error Flag SER.DESATER is set.
3. Assertion of signal NFLTA.
Programmability
Yes (blanking time).
In-System Testability
Yes (see also Chapter 3.5.3 and Chapter 3.5.4).
The DESAT function aims at protecting the IGBT in case of short circuit. The voltage drop VCE over the IGBT is
monitored via the DESAT pin while the device issues a PWM ON command. The voltage at pin DESAT is
externally filtered by an external RC filter, and decoupled by an external diode (see Figure 3-1).The DESAT
voltage is compared to an internal reference voltage. The result of this comparison is available by reading bit
SSTAT2.DSATC.
EiceDRIVER ™ SIL
5V
Vcc2
DSAT _Sup_active
Logic
Class A
Generation
Comp
DSAT
Fixed Vref
Voltage
Divider
DESAT
Clamping_active
GND2
Figure 3-1 DESAT Function: Diagram of Principle
At the beginning of a turn-on sequence, the voltage at pin DESAT is forced to Low level for the duration the
blanking time defined by register SDESAT. Once the blanking time has elapsed, the voltage at pin DESAT is
released and is compared to an internal reference voltage. Depending on the value of the decoupling capacitance,
an additional “analog” blanking time will be added corresponding to the charging of the capacitance through the
internal pull-up resistance (Figure 3-2).
In case the measured voltage is higher than the internal threshold, an Emergency (Safe) Turn-Off sequence is
initiated, bit SER.DESATER is set and a fault notification is issued on pin NFLTA (in case of an OPM transition
the state machine - see Chapter 2.4.7).
Datasheet
55
Hardware Description
Rev. 3.1, 2015-07-30