SM8136A Datasheet, PDF (10/15 Pages) Nippon Precision Circuits Inc – White LED Driver IC

SM8136A
A mode hold signal of 200µs (max) duration is output immediately after switching to ×1.0 mode. The V_OUT
output is held in ×1.0 mode and any LED drive current insufficient detection signal is ignored during the mode
hold signal output. For example, if the V_IN voltage drops and the V_OUT output voltage in ×1.0 mode cannot
provide sufficient current to drive the LEDs, a LED drive current insufficient condition occurs momentarily due
to the mode reset. The LED low-current detector circuit outputs a LED drive current insufficient signal imme-
diately after switching modes, but during the mode hold time the device stays in ×1.0 mode and does not
switch to ×1.5 mode. Consequently, the V_OUT voltage drops and the LED brightness decreases during the 85µs
(min) to 200µs (max) mode hold time. However, a 200µs decrease in the brightness is not a problem as it is not
perceptible to the human eye.
VIN voltage
Mode reset
(1 sec/cycle)
Mode hold max
(L: hold) 200µS
VOUT mode
(H: 1.5, L: 1.0)
VOUT voltage
1.0sec
1.0 1.5 threshold
5.0V
Low ILED detector
(H: Low ILED)
V_OUT drop due to mode reset signal
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