BD9285F Datasheet, PDF (15/39 Pages) Rohm – Boost 1channel white LED driver For large LCDs

BD9285F
Datasheet
●3.2 The detection condition list of the protection (TYP. Condition)
Protection
Detect condition
Detectio
n pin
pin condition ^{PWM1 and}
SS
PWM2
Release
condition
LED OPEN ISENSE ISENSE < 0.1V H(4ck) SS>3.0V ISENSE > 0.1V
Timer
operation
4096 count
Protection type
Latch off
LED OCP
ISENSE ISENSE > 4.0V
-
-
ISENSE < 4.0V 4096 count
Latch off
UVLO
UVLO
UVLO<2.8V
-
-
UVLO>3.0V
NO
Auto recovery
TC54 UVLO
TC54
TC54<2.4V
-
-
TC54>2.5V
NO
Auto recovery
VCC UVLO
VCC
VCC<7.2V
-
-
VCC>7.5V
NO
Auto recovery
OVP
OVP
OVP>3.0V
-
-
OVP<2.9V
4 count
Latch off
SCP
OVP
OVP<0.2V
-
SS>3.0V OVP>0.25V
4096 count
Latch off
OCP
CS
CS>0.5V
-
-
-
NO
Pulse by Pulse
To reset the latch type protection, please input of STB logic to ‘L’ once. Otherwise the detection of VCCUVLO, TC54UVLO is
required.
●3.3 The behavior list of the protection
Protect Function
DC/DC Gate
output
The operation of the protection
Dimming transistor
(DIMOUT) logic
Soft Start
LED OPEN
Stops after latch
H after 4clk, L after latch
discharge after latch
LED OCP
Stops immediately
H immediately, L after latch
discharge after latch
STB
Stops immediately
L if TC54<2.4V
discharge immediately
UVLO
Stops immediately
immediately L
discharge immediately
TC54 UVLO
Stops immediately
immediately L
discharge immediately
VCC UVLO
Stops immediately
immediately L
discharge immediately
OVP
Stops immediately
immediately L
discharge after latch
SCP
Stops immediately
immediately L
discharge after latch
OCP
Stops immediately
Normal operation
Not discharge
Please refer to the timing chart in the section 3.7 for the detail.
FAILB pin
L after latch
L after latch
OPEN
immediately L
immediately L
immediately L
L after latch
L after latch
OPEN
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TSZ22111・15・001
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TSZ02201-0F1F0C100030-1-2
11.Jul.2012 Rev.001