BD93942F Datasheet, PDF (13/30 Pages) Rohm – White LED Driver for large LCD Panels (DCDC Converter type)

BD93942F
LED current setting
Setting of LED output current “ILED” can be made by connecting a resistor RISET to the ISET pin.
RISET vs. ILED current relation equation
R_ISET

7500
I _LED [mA]
[k]
　
(ADIM=2.5V)
However, LED current setting should be made in the range of 30mA to 150mA.
[Setting example]
To set ILED current to 100mA, RISET resistance is given by the following equation:
R_ISET

7500 _ 7500
I _LED [mA] 100[mA]
 75
[k]
　
DC/DC converter drive frequency setting
DC/DC converter drive frequency is determined by making RT resistance setting.
Drive frequency vs. RT resistance (ideal) relation equation
R _RT

15000
f _SW [kHz ]
[k]
where fsw  DC/DC converter oscillation frequency [kHz]
This equation has become an ideal equation without any correction item included.
For accurate frequency settings, thorough verification should be performed on practical sets.
[Setting example]
To set DC/DC drive frequency “fsw” to 200 kHz, RRT is given by the following equation:
R_RT

15000 _ 15000 _{ 75}
f _sw[kHz] 200[kHz]
[k]
　
Datasheet
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TSZ22111・15・001
13/26
TSZ02201-0F5F0C100050-1-2
12.Aug.2015 Rev.002