STGAP1S Datasheet, PDF (30/67 Pages) STMicroelectronics – Negative gate drive ability

Functional description
STGAP1S
7.5
Thermal warning and shutdown protection
The device provides a thermal warning and a thermal shutdown protection.
When junction temperature reaches the T_WN temperature threshold the TWN flag in the
STATUS1 register is forced high. The TWN flag is released as soon as the junction
temperature is lower than T_WN - T_hys.
When junction temperature reaches the T_SD temperature threshold, the device is forced in
“safe state” and the TSD flag in the STATUS1 register is forced high. The device operation is
restored and the TSD flag is released as soon as the junction temperature is lower than
T_SD - T_hys.
7.6
Desaturation protection
This feature allows implementing an overload protection for the IGBT. The DESAT pin
monitors the V_CE voltage of the IGBT while it is on, and if the protection threshold is
reached, the IGBT is turned off.
When the IGBT is off (GOFF output is activated) the DESAT pin is kept low internally and
the external blanking capacitor connected to the DESAT pin is discharged (the internal
current generator is fully switched off and the switch between DESAT and GNDISO pins is
turned on).
When the GON output is activated the switch between DESAT and GNDISO pins is turned
off and an internal programmable current generator (I_DESAT) starts charging the external
blanking capacitor after a fixed blanking time t_BLK.
If a desaturation event occurs the V_CE voltage increases and the voltage at the DESAT pin
reaches the desaturation threshold V_DESATth: the DESAT comparator output is set, the
device is forced in “safe state” and the DESAT flag is forced high and latched.
The DESAT comparator is not active when the external IGBT is off or after desaturation
detection (see Figure 11).
Both the V_DESATth threshold and the I_DESAT blanking current are programmable through the
SPI.
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