BD9483F Datasheet, PDF (20/32 Pages) Rohm – White LED Driver for large LCD Panels (DCDC Converter type)

BD9483F,FV
●3.7 Timing chart
●3.7.1 starting up 1 (STB inputs and PWM signal succeeds)
Datasheet
Figure 33.
(*1)…REG90 starts up when VCC is more than 7.0V and STB=H.
(*2)…When REG90 is more than 6.5V, the reset signal is released. The pin SS is not charged in the state that the PWM signal is
not input, the boost is not started.
(*3)…The charge of the pin SS starts by the positive edge of PWM1orPWM2=L to H, and the soft start starts. 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.
Please refer to the section “●3.1 Pin Function/SS”.
(*4)…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
voltage where the set LED current flows. It is started to monitor the abnormal detection of FBMAX.
(*5)…As STB=L, instantaneously the boost operation is stopped. (GATEx=L, SS=L)
(*6)…As STB=H again, the boost operation restarts by the next PWM=H. It is the same operation as the timing of (*2).
www.rohm.com
© 2012 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
20/29
TSZ02201-0F1F0C100100-1-2
28.Nov.2013 Rev.003