TLD5095EL Datasheet, PDF (19/31 Pages) Infineon Technologies AG – DC/DC Boost, Buck-Boost, SEPIC controller

TLD5095EL
Protection and Diagnostic Functions
9
Protection and Diagnostic Functions
9.1
Description
The TLD5095EL has integrated circuits to diagnose and protect against output overvoltage, open load, open
feedback and overtemperature faults. In case any of the four fault conditions occur the Status output ST will output
an active logic low signal to communicate that a fault has occurred. During an overvoltage or open load condition
the gate driver outputs SWO and PWMO will turn off. Figure 11 illustrates the various open load and open
feedback conditions. In the event of an overtemperature condition (Figure 14) the integrated thermal shutdown
function turns off the gate drivers and internal linear voltage regulator. The typical junction shutdown temperature
is 175°C. After cooling down the IC will automatically restart operation. Thermal shutdown is an integrated
protection function designed to prevent immediate IC destruction and is not intended for continuous use in normal
operation.
Input
Output
Overvoltage
Open Load
Open Feedback
Protection and
Diagnostic Circuit
OR
Output
SWO and PWMO
Gate Driver Off
Overtemperature
OR
Input
Undervoltage
Linear Regualtor
Off
Figure 9
Pro_Diag_BlckDiag.vsd
Protection and Diagnostic Function Block Diagram
Input
Condition
Level *
ST
Overvoltage
False
H
True
L
Open Load
False
H
True
L
Open Feedback
False
True
H
L
Overtemperature
False
True
H
L
*Note:
Sw = Switching
False = Condition does not exist
True = Condition does exist
Figure 10 Status Output Truth Table
Datasheet
19
Output
SWO PWMO
Sw* H or Sw *
L
L
Sw* H or Sw *
L
L
Sw* H or Sw *
L
L
Sw* H or Sw *
L
L
IVCC
Active
Active
Active
Active
Active
Active
Active
Shutdown
Pr o _Diag_ TT.vsd
Rev. 1.1, 2009-12-16