bd8621efv ROHM Co. Ltd., bd8621efv Datasheet - Page 9

• Manufacturer Part Number: bd8621efv
• Description: Built-in 1ch Fet Synchronous Rectification Type Dc/dc Converters
• Manufacturer: ROHM Co. Ltd.

●Protection function
Protection circuit is effective for destruction prevention due to accident so that avoid using under continuous protection
operation.
Low voltage protection function (LVP)
The voltage of the terminal FB (2 pins) is compared with internal reference voltage VREF.
If FB terminal voltage falls below V
and the state is fixed. In that case , PDET (3pin) output changes to L.
Over voltage protection function(OVP)
The voltage of the terminal FB is compared with internal reference voltage VREF.
If FB terminal voltage is over Vovp (=VREF +60mV) and the state is continues for 500usec, output changes to low
voltage and the state is fixed.
Table 4-1 output low voltage protection function
＊ Low voltage protection function is available when SS terminal voltage becomes more than
Table 4-2 output overvoltage protection function
＊ Over voltage protection function is available when SS terminal voltage becomes more than
terminal
terminal
>V
>V
<V
1.4V (typ) in the transition to ON control (during soft start).
<V
1.4V (typ) in the transition to ON control (during soft start).
EN
EN
ENH
ENH
ENL
ENL
FB terminal voltage
PDET terminal
Protection
SS terminal
SS terminal
>1.4V(typ)
<1.4V(typ)
>1.4V(typ)
<1.4V(typ)
-
-
LVP
HIGH
V
LOW
OFF
(= VREF -60mV) and the state continues for 500us, output changes to low voltage
ON
FB
0
LVP
FB terminal
FB terminal
Fig.4 Output voltage error detection range
＞V
＜V
＜V
＞V
-
-
-
-
OVP
OVP
LVP
LVP
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OVP
protection function
protection function
Over voltage
Low voltage
Effective
Invalidity
Invalidity
Effective
Invalidity
Invalidity
protection operation
protection operation
LVP
VREF＋60ｍV
VREF-60ｍV
VREF
Over voltage
Low voltage
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON