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Datasheet

Datasheet

BM2PXX2

TSZ02201-0F2F0A200030-1-2

24. Sep.2015.Rev.005

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

www.rohm.com

TSZ22111・15・001

(3) VCC pin protection function

BM2PXX2 built in VCC low voltage protection function VCCUVLO (Under Voltage Lock Out), over voltage protection

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

VCC UVLO and VCC OVP monitor VCC pin and prevent VCC pin from destroying switching MOSFET at abnormal voltage.

VCC charge function stabilizes the secondary output voltage by charging from the high voltage line by start circuit at

dropping the VCC voltage.

(3-1) VCC UVLO ／ VCC OVP function

VCCUVLO is auto recovery protection. VCCOVP is auto recovery protection. And they have voltage hysteresis. Refer to

the operation figure-8.

Swiching is stopped by the VCCOVP function when VCC pin voltage > Vovp1 (typ=27.5V), and Swiching is restart when

VCC pin voltage < Vovp2 (typ=23.5V)

Figure 8. VCC UVLO / OVP Timing Chart

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

B: VCC> V

G: VH is OPEN.VCC Voltage is fall.

H: Same as C.

I: Same as D.

J: VCC<Vuvlo2, Switching is stopped by the VCC UVLO function