Datasheet

Datasheet

21/29

TSZ02201-0F1F0C100100-1-2

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

28.Nov.2013 Rev.003

www.rohm.com

TSZ22111・15・001

BD9483F,FV

●3.7.2 starting up 2 (PWM signal inputs and STB succeeds)

VCC

STB

GATEx

REG90

SS

4.0V

SS

SS

STANDBY

(*1) (*2)

(*3)

(*4)

(*5)

NORMAL

FAILB

PWM1

orPWM2

0.4V

0.4V

7.0V

6.5V

H

OFF

(*1)…REG90 starts up when STB=H.

(*2)…When REG90 is more than 6.5V, the reset signal is released. In the first PWM=H the soft-start begins the changing

immediately. The GATEx pulse outputs only during the corresponding PWMx=H. And as the SS is less than 0.4V(typ), the

pulse does not output. The pin SS continues charging in spite of the assertion of PWM or OVP level.

(*3)…The soft start interval will end if the voltage of the pin SS, Vss reaches to 4.0V. By this time, BD9483F,FV boost Vout to the

point where the set LED current flows. It is started to monitor the abnormal detection of FBMAX.

(*4)…As STB=L, instantaneously the boost operation is stopped. (GATE=L, SS=L)

(*5)…As STB=H again, it is the same operation as the timing of (*1).

Figure 34.