Datasheet

RES
LM25117
VCC
C
RES
RES
LM25117
RES
LM25117
VCC
(a) Hiccup Mode
Current Limit
(b) Latch-off Mode
Current Limit
(c) Cycle-by-cycle
Current Limit
RES
RESTART
TIMER
HICCUP MODE
FAULT TIMER
256 CYCLES
RES
Current
STANDBY
HICCUP
Current Limit
Comparator
C
RES
+
-
LM25117
HO
LO
SS
RES
0V
1.25V RES Threshold
0.8V REF
Current Limit
Detected
Current Limit
persists during 256
consecutive cycles
t
SS
t
RES
I
RES
= 10 µA
I
SS
= 10 µA
LM25117
LM25117-Q1
SNVS714E –APRIL 2011–REVISED MARCH 2013 www.ti.com
Figure 27. Hiccup Mode Current Limit Timing Diagram
Figure 28. Hiccup Mode Current Limit Circuit
The RES pin can also be configured for latch-off mode current limiting or non-hiccup mode cycle-by-cycle current
limiting. If the RES pin is tied to VCC or a voltage greater than the RES threshold at initial power-on, the restart
timer is disabled and the regulator operates with non-hiccup mode cycle-by-cycle current limit. If the RES pin is
tied to GND, the regulator enters into the standby mode after 256 consecutive cycles of current limiting and then
never restarts until UVLO shutdown is cycled. The restart timer is configured during initial power-on when UVLO
is above the UVLO threshold and VCC is above the VCC UV threshold.
Figure 29. RES Configurations
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