BD9489F Datasheet, PDF (29/39 Pages) Rohm – DCDC converter with current mode

BD9489F
3.5.5 OVP Detection
Datasheet
STB
PWM
REG58
OVP
Abnormal
COUNTOR
SS
GATE
3.0V
2.8V
3.0V
2.8V
Smaller than
Gate 4count
Gate 4count
3.0V 2.8V
0.4V
Smaller than
4count
DIMOUT
RT
2.0V
STATE NORMAL OVP
NORMAL
OVP
Latch off Reset NORMAL
OVP
abnormal
(*1)
(*2)
abnormal
(*3)
(*4) (*5)
(OFF)
(*6)
(*7)
abnormal
(*8)
NORMAL
Figure 40. OVP Detection
(*1)…As OVP is detected, the output GATE=L, DIMOUT=L, and the abnormal counter starts.
(*2)…If OVP is released within 4 clocks of abnormal counter of the GATE pin frequency, the boost operation restarts.
(*3)…As the OVP is detected again, the boost operation is stopped.
(*4)…As the OVP detection continues up to 4 count by the abnormal counter, IC will be latched off.
(*5)… Once IC is latched off, the boost operation doesn't restart even if OVP is released.
(*6)…The STB=L input can make IC reset.
(*7)…It normally starts as STB turns Low to High.
(*8)…The operation of the OVP detection is not related to the logic of PWM.
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29.Oct 2014 Rev.002