SM8136A Datasheet, PDF (7/15 Pages) Nippon Precision Circuits Inc – White LED Driver IC

SM8136A
Immediately after startup, the device operates in ×1.5 mode for a fixed interval (soft start time: approximately
2ms) to set the current for LEDs connected to the DIN pins.
VIN
VIN High
EN
LED current
Dimming pulse enable
(1)
Soft start time
typ: 2ms
LED ON
(2)
Soft start time and LED current
(1) If the EN signal is input after power is applied, the soft start time begins on the EN rising edge. The EN
input signal for dimming is active during the soft start time.
(2) The LED drive starts immediately before the end of the LED turn-on delay time.
Switching to Standby Mode
The SM8136A operating mode switches from ×1.0/×1.5 mode to standby mode if EN goes LOW and stays
LOW for an interval of 1.00ms (typ). This function is used to switch the internal circuits to standby mode auto-
matically when the LEDs turn OFF in order to reduce current consumption.
EN
LED current
CE hold time
typ: 1.00ms
1.0 or 1.5
Standby
mode
Switching to standby mode, and EN hold time
I When EN is LOW for longer than the CE hold time of 1.00ms (typ), the SM8136A switches to standby
mode. In standby mode, the internal circuits are reset, hence the drive current settings must be re-entered to
restart the device.
SEIKO NPC CORPORATION —7