BD8119FM-M_14 Datasheet, PDF (13/31 Pages) Rohm – White Backlight LED Driver For Medium to Large LCD Panels

BD8119FM-M
(10) LED Short Detection
When the LED-pin voltage  4.7V (Typ) and OVP-pin voltage  1.6V (Typ) simultaneously, the internal counter starts
operating and the only detected channel (as LED short) latches OFF approximately after 100ms (when fOSC= 300kHz).
With the PWM brightness control, the detecting operation is processed only when PWM-pin = High. If the condition of
the detection operation is released before 100ms (when fOSC = 300kHz), then the internal counter resets.
(Note) The counter frequency is the DCDC switching frequency determined by the RT. The latch proceeds at the count of 32770.
Protection
Detecting Condition
[Detect]
[Release]
Operation after detect
UVLO
VREG<4.3V
VREG>4.5V
All blocks shut down
TSD
Tj>175°C
Tj<150°C
All blocks (except VREG)
shut down
OVP
VOVP>2.0V
VOVP<1.45V
SS discharges
OCP
SCP
LED open
LED short
VCS≤VCC-0.6V
VLED<0.3V
(100ms delay when
fOSC=300kHz)
VLED<0.3V & VOVP>1.7V
VLED>4.7V & VOVP<1.6V
(100ms delay when
fOSC=300kHz)
VCS>VCC-0.6V
EN or UVLO
EN or UVLO
EN or UVLO
SS discharges
Counter starts and then latches OFF
all blocks (except VREG)
Only the detected channel latches
OFF
Only the detected channel latches
OFF
(after the counter sets)
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TSZ22111・15・001
13/27
TSZ02201-0T3T0C600030-1-2
28.Aug.2014 Rev.001