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Datasheet

Datasheet

BM2PXX4 Series

TSZ02201-0F2F0A200070-1-2

28.NOV.2012.Rev.003

© 2012 ROHM Co., Ltd. All rights reserved.

www.rohm.com

TSZ22111・15・001

(3) VCC pin protection function

BM2PXX4 built in VCC low voltage protection function of VCCUVLO (Under Voltage Lock Out), over voltage protection

function of VCC OVP (Over Voltage Protection) and VCC charge function that operates in case of dropping the VCC

voltage.

This function monitors VCC pin and prevent VCC pin from destroying switching MOSFET at abnormal voltage.

VCC charge function stabilizes the secondary output voltage to be charged from the high voltage line by start circuit at

dropping the VCC voltage.

(3-1) VCC UVLO ／ VCC OVP function

VCCUVLO is auto recovery comparator. VCCOVP is auto recovery comparator that has voltage hysteresis.

Refer to the operation figure-8.

VCCuvlo1=13.5Vtyp

ON

OFF

Vovp1=27.5Vtyp

Vchg2= 8.7Vtyp

ON

OFF

OFF

ON

OFF

A

BC

D

F

OFF

G

H

IJ

VCCuvlo2 8.2Vtyp

A

Vovp1=23.5Vtyp

ON

ON

OFF

ON

Vchg1=13.0Vtyp

E

Figure 8. VCC UVLO / OVP Timing Chart

A:DRAIN voltage input, VCC pin voltage starts rising.

B:VCC>Vuvlo1, DC/DC operation starts

G:VH is OPEN.VCC Voltage is fall.

H:Same as C.

I:Same as D.

J: VCC<Vuvlo2, DC/DC operation stops