SM8135A
Immediately after startup, the device operates in ×1.5 mode for a fixed interval (soft start time: approximately
1.43ms) to set the current for LEDs connected to the DIN pins. After the soft start time has elapsed, the LEDs
are turned ON. Approximately 2ms is required for the LED drive current to reach the set drive value.
(1)
EN input signal
Soft start time
typ: 1.43ms
typ: 2ms
LED ON
LED current
(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 PWM
signal input for dimming is active during the soft start time.
(2) After the soft start time (1.43ms) has elapsed, the LEDs are turned ON. Approximately 2ms is required for
LED drive current to reach set values.
Switching to Standby Mode
The SM8135A switches from ×1.0/×1.5/×2.0 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 automatically
when the LEDs turn OFF in order to reduce current consumption.
EN
CE hold time
typ: 1.00ms
Standby
mode
LED current
1.0 or 1.ꢁ
EN input signal and internal enable signal “CE”
ꢀ If EN is LOW for longer than the enable hold time of 1.00ms (typ), the SM8135A switches to standby mode.
In standby mode, the internal circuits are reset.
SEIKO NPC CORPORATION —8
NPC [ NIPPON PRECISION CIRCUITS INC ]
