SM8134A Datasheet, PDF (11/19 Pages) Nippon Precision Circuits Inc – White LED Driver IC

SM8134A
VIN
input voltage
Low ILED
detector
VOUT mode
1.0 mode
VOUT
output voltage
Low ILED
detected
1.5 mode
1.0 1.5 threshold
(1)
(2)
4.9V ₍₃₎
V_IN voltage drop and V_OUT output voltage
(1) When V_IN falls, V_OUT cannot overcome the LED “VF” rating, causing insufficient current flows and the
I_LED low-current signal becomes active.
(2) When the I_LED low-current condition is detected, the V_OUT output circuit switches to ×1.5 mode (charge
pump mode).
(3) Prior to switching to ×1.5 mode, the V_OUT voltage may be lower than 4.9V but sufficient current is sup-
plied to the LED.
If after startup, the LED connected to a DIN pin is switched, the LED connection detector circuit flags an error,
and correct mode switching may not occur. If the DIN pin does not control the LED drive current, the low-cur-
rent detector does not operate and the device cannot switch to ×1.5 mode.
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