TLE7184F_15 Datasheet, PDF (29/38 Pages) Infineon Technologies AG – System IC for B6 motor drives

TLE7184F
Description of Modes, Protection and Diagnostic Functions
If the voltage at VREG reaches the Under Voltage diagnosis level V_UVVR for a minimum specified filter time, an
error is set and the IC goes into Error Mode.
As long as the VS Under Voltage Lock Out is not reached, the low side MOSFETs will stay actively switched off.
The status of the high side MOSFET drivers is dependent on the bootstrap voltage - which depends on the SHx
voltage. It is expected that the SHx nodes will be pulled to VDH level by the high side MOSFETs and this will switch
off the high side MOSFETs passively.
In this situation the short circuit detection of this output stage is deactivated to avoid wrong error reporting.
9.2.8 VREG Under Voltage Shut Down (VREG_UVSD)
The TLE7184F has an integrated VREG Under Voltage Shut Down to avoid operation with VREG shorted to GND.
If the supply voltage at VREG reaches the Under Voltage shut down level V_VRSD, “AND” no Over Temperature
Prewarning is set “AND” the wake up time is expired, VREG will be switched off and the IC will go to the VREG
Shut Down Mode. In this condition the µC is still supplied and can communicate via the PWM interface (IFMA),
the MOSFETs are switched off and an error is set. The only way to leave this mode is to go to “Sleep Mode”.
If the supply voltage at VREG reaches the Under Voltage shut down level V_VRSD “AND” Over Temperature
Prewarning is set “AND” the wake-up time is expired, VREG and VDD will be switched off and the IC will go to the
“Dead Lock Mode”.
The only way to leave this Deadlock Mode is to provoke a VS Under Voltage Shut Down, for example by removing
the battery voltage.
9.2.9 IOV and VDH Over Voltage Shut Down (IOV_OVSD, VDH_OVSD)
The TLE7184F has an integrated Over Voltage shut down to minimize the risk of destruction of the IC at high
supply voltages caused by violation of the maximum ratings.
The voltages are observed at the Over Voltage input pin IOV and at the VDH pin. If the voltage at the IOV pin or
at the VDH pin exceeds the Over Voltage shut down level for more than the specified filter time, the IC goes into
Error Mode.
The effective Over Voltage level can be adjusted by a voltage divider at the IOV pin. This voltage devider is
normally supplied by the VDHS pin. The Over Voltage level at VDH is fix.
9.2.10 Dead Time and Shoot Through Protection
In bridge applications it has to be assured that the external high side and low side MOSFETs are not “on” at the
same time, connecting the battery voltage directly to GND. The dead time generated in the TLE7184F is set to a
minimum value if the DT pin is connected to GND. This function assures a minimum dead time if a common input
signal for ILx and IHx is used.
The dead time can be increased by connecting the DT pin via a dead time resistor R_DT to GND. Larger dead time
resistors result in a longer dead time.
The typical dead time can be calculated with the following formula:
t_deadtime
=
0.081
0.02 + ^2.44_+Rdt
µs
Please put in the R_dt in kΩ.
If an exact dead time of the bridge is needed, the use of the µC PWM generation unit is recommended.
In case of an open DT pin, the dead time is set to the internal maximum value.
In addition to this dead time, the TLE7184F provides a locking mechanism avoiding that both external MOSFETs
of one half bridge can be switched on at the same time. This functionality is called shoot through protection.
Data Sheet
29
Rev. 1.1, 2011-04-08