TLD5098EL Datasheet, PDF (21/39 Pages) Infineon Technologies AG – DC/DC Boost, Buck-Boost, SEPIC controller

TLD5098EL
Protection and Diagnostic Functions
9
Protection and Diagnostic Functions
9.1
Description
The TLD5098EL has integrated circuits to diagnose and protect against output overvoltage, open load, open
feedback and overtemperature faults. Additionally the FBH and FBL potential is monitored and in case the LED
load short circuits to GND (see description Figure 15) the regulator stops the operation and protects the system.
In case any of the six fault conditions occur the PWMO and IVCC signal will change to an active logic LOW signal
to communicate that a fault has occurred (detailed overview in Figure 9 and Figure 10 below). Figure 11
illustrates the various open load and open feedback conditions. In case of an overtemperature condition the
integrated thermal shutdown function turns off the gate drivers and internal linear voltage regulator. The typical
junction shutdown temperature is 175°C (T_j,SD Parameter 9.2.2). After cooling down the IC will automatically
restart. Thermal shutdown is an integrated protection function designed to prevent IC destruction and is not
intended for continuous use in normal operation (Figure 13). To calculate the proper overvoltage protection
resistor values an example is given in Figure 14.
Input
Output
Overvoltage
Open Load
Short to GND
Open Feedback
Overtemperature
Input
Undervoltage
Protection and
Diagnostic Circuit
OR
OR
Figure 9 Protection and Diagnostic Function Block Diagram
Output
SWO and PWMO
Gate Driver Off
Linear Regualtor
Off
Datasheet
21
Rev. 1.0, 2010-10-13