BD9489F Datasheet, PDF (12/39 Pages) Rohm – DCDC converter with current mode

BD9489F
Datasheet
2.6 Detection Condition List of the Protect Functions (TYP Condition)
Protect Function
Detection
Pin
Detect Condition
Detection
Condition
PWM
SS
FBMAX
FB
FB > 4.0V
H(4clk) SS>3.7V
Release
Condition
FB < 4.0V
Timer
Operation
CP charge
Protection Type
Latch off
LED OCP
ISENSE
ISENSE > 3.0V
-
-
ISENSE < 3.0V
4clk
Latch off
RT GND SHORT
RT
RT<VRT×90%
-
RT HIGH SHORT
RT
RT>5V
-
-
Release
RT=GND
NO
Restart by release
-
Release
RT=HIGH
NO
Restart by release
UVLO
UVLO
UVLO<2.7V
-
-
UVLO>3.0V
NO
Restart by release
REG58UVLO
REG58
REG58<2.3V
-
-
REG58>2.6V
NO
Restart by release
VCC UVLO
VCC
VCC<7.2V
-
-
VCC>7.5V
NO
Restart by release
OVP
OVP
OVP>3.0V
-
-
OVP<2.8V
4clk
Latch off
OCP
CS
CS>0.4V
-
-
-
NO
Pulse by Pulse
OCP LATCH
CS
CS>1.0V
-
-
CS<1.0V
4clk
Latch off
To reset the latch type protection, please set STB logic to ‘L’ once. Otherwise the detection of VCCUVLO, REG58UVLO is
required.
The clock number of timer operation corresponds to the boost pulse clock.
2.7 Behavior List of the Protect Function
Protect Function
DC/DC Gate
Output
Operation of the Protect Function
Dimming Transistor
(DIMOUT) Logic
SS Pin
FBMAX
Stops after latch
L after latch
discharge after latch
LED OCP
Stops immediately H immediately, L after latch
discharge after latch
RT GND SHORT
Stops immediately
immediately L
Not discharge
RT HIGH SHORT
STB
UVLO
Stops immediately
Stops immediately
Stops immediately
immediately L
L after REG58UVLO
detects
immediately L
Not discharge
discharge immediately
discharge immediately
REG58UVLO
Stops immediately
immediately L
discharge immediately
VCC UVLO
Stops immediately
immediately L
discharge immediately
OVP
Stops immediately
immediately L
discharge after latch
OCP
Stops immediately
Normal operation
Not discharge
OCP LATCH
Stops after latch
L after latch
discharge after latch
Please refer to section “3.5 Timing Chart” for details.
RT pin
(FAILB logic)
L after latch
L after latch
-
-
L after REG58UVLO
detects
H (2.0V)
H (2.0V)
H (2.0V)
L after latch
H (2.0V)
L after latch
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TSZ02201-0F1F0C100250-1-2
29.Oct 2014 Rev.002