SM8136AB datasheet(10/15 Pages) NPC

10 / 15 page

SM8136A

SEIKO NPC CORPORATION —10

A mode hold signal of 200

µs (max) duration is output immediately after switching to ×1.0 mode. The VOUT

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 VIN voltage drops and the VOUT 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 VOUT voltage drops and the LED brightness decreases during the 85µs

(min) to 200

µs (max) mode hold time. However, a 200µs decrease in the brightness is not a problem as it is not

perceptible to the human eye.

VOUT drop due to mode reset signal

Mode reset

(1 sec/cycle)

Mode hold

(L: hold)

Low ILED detector

(H: Low ILED)

VOUT voltage

VIN voltage

1.0sec

5.0V

max

200

µS

VOUT mode

(H: 1.5, L: 1.0)

1.0

1.5 threshold

SM8136AB Datasheet(PDF) 10 Page - Nippon Precision Circuits Inc