BD9415FS Datasheet, PDF (16/34 Pages) Rohm – White LED Driver for 4Ch Large LCD Panels (DC/DC converter type)

BD9415FS
3.2.9 ODP setting
RDUTYP which connects to ODP pin sets the ODP detection duty.
○Relationship between LED PWM frequency fPWM, ODP Detection Duty and DUTYP resistance (ideal)
R_DUTYP

1172  ODP_duty[%]
f _PWM [Hz]
[k]　
N
【setting example】
When LED PWM frequency fPWM, is set to 120Hz and ODP
R_DUTYP
DUTYP
CS
Detection Duty (ODPduty) is set to 35%, RDUTYP is as follows.
Gx
R_DUTYP

1172  35[%]
120[Hz]

341.8[k]　
PWM
Sx
GND
R_CS
R_S
fPWM
PWM
Figure 18. ODP setting example
GA^NTE
DIMO^GU^x T
ODPduty
Figure 19. The GATE and the DIMOUT waveform as PWM dimming (ODP)
3.2.10 Timer Latch Time (CP Counter) Setting, Auto-Restart Timer Setting
Timer latch time (CP Counter) is set by counting the clock frequency which is set at the RT pin. About the behavior from
abnormal detection to latch-off, please refer to the section “3.5.2 and 3.5.3 Timing Chart”.
When various abnormal conditions happen, counting starts from the timing, latch occurs after below time has passed.
Furthermore, even if PWM=L, if abnormal condition continues, timer count will not reset.
LATCH_TIME

2¹⁴

R_RT []
1.5 10¹⁰

16384

100[k]
1.5 10⁷
 [s]　
AUTO_TIME

2¹⁷

R_RT []
1.5 10¹⁰

131072

100[k]
1.5 10⁷
[s]　
Here, LATCHTIME = time until latch condition occurs, AUTOTIME = auto restart timer’s time
RRT = Resistor value connected to RT pin
【setting example】
Timer latch time when RT=30kohm (500kHz)
LATCH_TIME

16384

R_RT [k]
1.5 10⁷

16384

30[k]
1.5 10⁷
 32.8[ms]　
AUTO_TIME

131072

R_RT [k]
1.5 10⁷

131072

30[k]
1.5 10⁷

262.1[ms]　
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TSZ22111・15・001
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TSZ02201-0F2F0C100140-1-2
23.May.2016 Rev.001