TLE7183QU

Data Sheet

16

Rev. 1.1, 2016-01-28

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 .

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.