BD93942F Datasheet, PDF (12/30 Pages) Rohm – White LED Driver for large LCD Panels (DCDC Converter type)

BD93942F
Datasheet
About unused LED terminal automatic detecting function
This IC is detected automatically that it is an unused channel by asssuming the LED terminal to be OPEN at starting. It
explains the sequence.
20us
GND
GND
Figure 13. Timming chart
Figure 14. Block diagram
Sequence;
① STB=PWM=ON
② All systems are ON and SSFB starts charging.
③ When the output voltage is boosted enough, and enough current flows through the LED, LED_OK signal is switched
in the IC. PWM=L from the Rise timing of this signal for about 20us
④ During this PWM=L period, LED pins with LED connections' output voltage becomes 0.2V and above, where as
unused LED pins are below 0.2V.
⑤ During this time, determination on whether the LED pins are 0.2V above/below is done.
⑥ After the determination, unused LED pins are pulled up to 5V.
⑦The AUTO timer don’t count.
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TSZ22111・15・001
12/26
TSZ02201-0F5F0C100050-1-2
12.Aug.2015 Rev.002