BD9470AEFV Datasheet, PDF (32/39 Pages) Rohm – White LED driver for medium sized and large sized LCD back light

BD9470AFM・BD9470AEFV
3.4 List of Protection Functions
●List of protection detecting condition
Protection
names
Detection
pin
Detection condition
Detection pin
condition
PWM
SS
LED OPEN
LEDｘ
LEDx < 0.20V
H SS>3.7V
LEDSHORT
LED GND
SHORT
ISET GND
SHORT
RT GND
SHORT
UVLO
LEDｘ
LEDｘ
ISET
RT
UVLO
LEDx > 9V
(LSP=OPEN)
LEDx < 0.20V
Under ISET×90%
Under RT×90%
UVLO<2.7V
H SS>3.7V
H SS>3.7V
-
-
-
-
REG58 UVLO REG58
REG58<2.4V
-
-
VCC UVLO
VCC
VCC<7.2V
-
-
OVP
OVP
OVP>3.0V
-
-
Release
condition
LEDx > 0.20V
LEDx < 9V
(LSP=OPEN)
LEDx > 0.20V
Canceled
ISET=GND State
Canceled
RT=GND State
UVLO>3V
REG58>2.6V
VCC>7.5V
OVP<2.9V
Timer
2 ¹⁶ count
2 ¹⁶ count
2 ¹⁶ + 2⁷
count
Immediately
detect
Immediately
detect
Immediately
detect
Immediately
detect
Immediately
detect
2 ¹⁸ count
Protection
type
Latch
(Only detected
ｃｈ)
Latch
(Only
detected ｃｈ)
Latch
Auto-restart
Auto-restart
Auto-restart
Auto-restart
Auto-restart
Latch
SCP
OVP
OVP<0.1V
-
-
OVP>0.1V
2 ¹⁶ count
Latch
OCP
CS
OCP>0.4V
-
-
* To clear the latch type, STB should be set to “L” once, and then to “H”
* The count of Timer means ” 1count = 1 duty of switching frequency.
-
Immediately
detect
Pulse-by-Pulse
●List of protection detecting operation
Protection Functions
Operation when the hysteresis type protection is detected
DC/DC
LED Driver
Soft start
FAIL pin
LED OPEN
LEDSHORT
LED GNDSHORT
ISET GND SHORT
RT GND SHORT
STB
UVLO
REG58 UVLO
VCC UVLO
OVP
SCP
Continues operation
Continues operation
Stops operating after
CP counting
Instantaneously stops
operating
Instantaneously stops
operating
Instantaneously stops
operating
Instantaneously stops
operating
Instantaneously stops
operating
Instantaneously stops
operating
Stops operating after
CP counting
Stops operating after
CP counting
Only detected LED stops
operating after CP counting
Only detected LED stops
operating after CP counting
Stops operating after CP counting
Instantaneously stops operating
Normal Operation
Stops (and REG58<2.4V)
Instantaneously stops operating
Instantaneously stops operating
Instantaneously stops operating
Stops operating after CP counting
Stops operating after CP counting
Not discharged
Not discharged
Discharge
Not discharged
Not discharged
Discharge
Discharge
Discharge
Discharge
Discharge
Discharge
Open after CP
counting
Open after CP
counting
Open after CP
counting
OPEN
immediately
LOW
OPEN
immediately
OPEN
immediately
OPEN
immediately
OPEN
immediately
Open after CP
counting
Open after CP
counting
OCP
limits duty cycle
Continues operation
Not discharged
LOW
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TSZ02201-0F10C1002000-1-2
19.Oct.2013 Rev.003