BD9778F-E2 View Datasheet(PDF) - ROHM Semiconductor

Part Name

Description

Manufacturer

BD9778F-E2

Flexible Step-down Switching Regulators with Built-in Power MOSFET

ROHM Semiconductor 

BD9778F, BD9778HFP, BD9001F, BD9781HFP

Timing chart

(BD9781HFP)

- While in basic operation mode

VIN

Internal

OSC

FB

SW

EN/SYNC

- While in overcurrent protection mode

IO

Internal

OSC

FB

Fig.27

Technical Note

SW

Output short circuit Auto reset

Auto reset

Auto reset

Auto reset

Fig.28

External synchronizing function (BD9781HFP)

In order to activate the external synchronizing function, connect the frequency setting resistor to the RT pin and then input

a synchronizing signal to the EN/SYNC pin. As the synchronizing signal, input a pulse wave higher than a frequency determined

with the setting resistor (RT). On the BD9781HFP, design the frequency difference to be within 50%. Furthermore,

set the pulse wave duty between 10% and 90%.

FSYNC

Internal

OSC

www.rohm.com

© 2010 ROHM Co., Ltd. All rights reserved.

Fig.29

8/16

: For RT only

: For external

synchronization

2010.02 - Rev. B

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