TLE7183QU Datasheet, PDF (16/28 Pages) Infineon Technologies AG – 3 Phase Driver IC Automotive Power

TLE7183QU
5.2
Protection and Diagnostic Functions
5.2.1 Short Circuit Detection
The TLE7183QU provides a short circuit detection for the external MOSFETs. It monitors their drain-source
voltage. It is active as soon as the corresponding input is set to "on" and the dead time has elapsed.
If the drain-source voltage is higher than the short circuit detection level, a timer will be started. After a delay of
about 6 µs all external MOSFETs will be switched off. The ERRx pins will indicate a short circuit. This error is not
self-clearing. The driver has to be reset using one of the ENAx pins.
The short circuit detection level is a fixed setting of the chip. Several options are available and described in
Chapter 5.2.8.
5.2.2 Overcurrent Warning
The TLE7183QU offers the possibility to have a warning at the ERRx pins if a current threshold is reached. (see
Figure 4 ).
The output of the current sense OpAmp is connected to an integrated comparator. It compares the amplified
current sense signal with an external adjustable threshold. After the comparator a blanking time (1.5 µs typ.) is
implemented to avoid false triggering caused by an overshoot of the current sense signal. If the overcurrent
situation is detected, there is a warning at the ERRx pins.
The driver remains in normal operation mode. The overcurrent warning is self-clearing. It will be cleared if the
current drops below the overcurrent limit set on the VTHOC pin. The overcurrent warning is also cleared if the
current commutates from the low side MOSFET to the associated high side MOSFET (no current through the
shunt resistor).
It is up to the user to react on the overcurrent warning by modifying the Ixx patterns to lower the current.
5.2.3 Dead Time and Shoot Through Protection
In bridge applications it has to be assured that the external high side and low side MOSFETs in a single half bridge
are not switched on at the same time. This would lead to a direct connection from battery voltage to GND. The
integrated mechanisms of TLE7183QU preventing this are called shoot through protection and minimum dead
time generation.
The shoot through protection is a locking mechanism which deals with faulty input commands at the Ixx pins. If the
command is given to switch on the high side and the low side MOSFET of a single half bridge at same time, it is
ignored. The driver output stages remain unchanged.
The dead time of a half bridge is the time after the command to switch off a MOSFET has been given during which
the command to switch on the other MOSFET is not executed. A minimum dead time has to be applied because
switching does not happen instantly. If both MOSFETs of a single half bridge start to switch at the same time, both
of them may be on at the same time causing the critical connection from battery voltage to ground. The dead time
assures that a MOSFET is only switched on after the other one has been switched off.
The exact dead time of the bridge is usually set by the PWM generation unit of the µC. The minimum dead time
generation of TLE7183QU assures a minimum dead time if the input signals from the µC are faulty. If the DT pin
is connected to GND, the generated minimum dead time is fixed to 50..200ns .
It can be increased by connecting the DT pin via a dead time resistor R_DT to GND - the larger the dead time resistor,
the larger the dead time (please see Programmable Internal Dead Time for details).
5.2.4 Undervoltage Shut Down
The TLE7183QU has an integrated undervoltage shut down, to assure that the behavior of the device is
predictable in all supply voltage ranges.
Data Sheet
16
Rev. 1.1, 2016-01-28