MAX1518B Datasheet, PDF (17/25 Pages) Maxim Integrated Products – TFT-LCD DC-DC Converter with Operational Amplifiers

IN
5µA
DEL
REF
TFT-LCD DC-DC Converter with
Operational Amplifiers
MAX1518B
2.5V
FB OK
FBP OK
FBN OK
SRC
Q1
COM
CTL
Q2
DRN
Figure 7. Switch-Control Block
Fault Protection
During steady-state operation, if the output of the main
regulator or any of the linear-regulator outputs does not
exceed its respective fault-detection threshold, the
MAX1518B activates an internal fault timer. If any con-
dition or combination of conditions indicates a continu-
ous fault for the fault-timer duration (200ms typ), the
MAX1518B sets the fault latch to shut down all the out-
puts except the reference. Once the fault condition is
removed, cycle the input voltage (below the UVLO
falling threshold) to clear the fault latch and reactivate
the device. The fault-detection circuit is disabled during
the soft-start time.
Thermal-Overload Protection
Thermal-overload protection prevents excessive power
dissipation from overheating the MAX1518B. When the
junction temperature exceeds T_J = +160°C, a thermal
sensor immediately activates the fault protection, which
shuts down all outputs except the reference, allowing
the device to cool down. Once the device cools down
by approximately 15°C, cycle the input voltage (below
the UVLO falling threshold) to clear the fault latch and
reactivate the device.
The thermal-overload protection protects the controller
in the event of fault conditions. For continuous opera-
tion, do not exceed the absolute maximum junction
temperature rating of T_J = +150°C.
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