BD9285F ROHM [Rohm], BD9285F Datasheet - Page 26

• Manufacturer Part Number: BD9285F
• Description: Boost 1channel white LED driver For large LCDs
• Manufacturer: ROHM [Rohm]

●3.7. Timing chart
(*1)…TC54 starts up if STB turns from L to H. The pin SS is not charged in the state that the PWM signal is not input, the boost
(*2)…The charge of the pin SS starts by the positive edge of PWM=L to H, and the soft start starts. The GATE pulse outputs
(*3)…The soft start interval will end if the voltage of the pin SS, Vss reaches to 3.0V. By this time, BD9285 boost Vout where the
(*4)…As STB=L, instantaneously the boost operation is stopped. (GATE=L, SS=L) On the other hand, the discharge circuit
(*5)…As STB=H again, the boost operation restarts by the next PWM=L to H. It is the same operation as the timing of (*1).
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TSZ22111・15・001
BD9285F
3.7.1 starting up 1 (STB inputs and PWM signal succeeds)
is not started.
only during PWM=H. And as the SS is less than 1.1V, the pulse does not output. The pin SS continues charging in spite of
the assertion of PWM and OVP.
set LED current flows. It is started to monitor the abnormal detection of SCP and OPEN.
works in the interval “STB=L and V5UVLO=H”. Please refer to the time chart in the section 3.7.3 for details.
Please refer to the section 3.4.1 for the setting of soft start external capacitance.
andPWM2
PWM1
GATE
FAILB
V5UVLO
TC54
SS
STB
VCC
OFF
7.5V
(*1)
STANDBY
2.5V
(*2)
1.1V
SS
26/36
3.0V
(*3)
Normal
(*4)
TSZ02201-0F1F0C100030-1-2
(Reset)
2.4V
OFF
(*5)
STANDBY
2.5V
1.1V
11.Jul.2012 Rev.001
SS
Datasheet