TLD5098EL_15 Datasheet, PDF (25/41 Pages) Infineon Technologies AG – Multitopology LITIX Power DC/DC Controller IC

Infineon® LITIX™ Power
TLD5098EL
Protection and Diagnostic Functions
Short to GND protection for Highside Return Applications (B2B) from Figure 11-7
The FBH and FBL pins features a Short to GND detection threshold (VFBL,FBH_S2G). If the potential on those
pins is below this threshold the Device stops his operation. This means that the PWMO signal changes to
inactive state (LOW potential) and the corresponding p-channel (TDIM2) is switched OFF accordingly and
protects the LED chain. For the B2B application some external components are needed to ensure a LOW
potential during a short circuit event. D1 and D2 are low power diodes (BAS16-03W) and the resistor Rlim
(10kOhm) is needed to limit the current through this path. The diode D3 should be a high power diode and is
needed to protect the RFB and the FBH and FBL pins in case of an short circuit to GND event. This short circuit
detection and protection concept considers potential faults for LED chains (LED Modules) which are
separated from the ECU via two wires (at the beginning and at the end of the LED chain). If the short circuit
condition disappears, the device will re-start with an soft start.
V_bb
C_IN
D1 Rlim
C_BO
D2
V_FBL,FBH
60V
R_FB
wire
harness
LED Module
wire
harness
T_DIM2
D3
D_n
D₁
Short to GND
Short to GND
Normal Operation
T_DIM1
PWMO
FBH
FBL
IN
L_BO
D_BO I_LED
SWO
SWCS
I_{SW TSWVOUT}
4.5V
V_{FBL,FBH_S2G}
Device working with parameter
deviations
Short Circuit detected on
SGND
FBH/FBL
t
Figure 9-7 Short Circuit to GND Protection
Data Sheet
25
Revision 1.2
2015-03-12