IS31FL3190
Integrated Silicon Solution, Inc. – www.issi.com 12
Rev.0A, 10/20/2015
TYPICAL APPLICATION
GENERAL DESCRIPTION
IS31FL3190 is a 1-channel LED driver with
two-dimensional auto breathing and PWM Control
mode. It can drive two individual LEDs.
PWM CONTROL
By setting the LED bits of the LED Mode Register (03h)
to “0”, the IS31FL3190 will operate in PWM Control
Mode. The PWM Register (Table 7, 04h) can modulate
LED brightness of one channel with 256 steps. For
example, if the data in PWM Register is “0000 0100”,
then the PWM is the fourth step, with a duty cycle of
4/256.
In PWM control mode, a new value must be written to
the PWM register to change the output PWM duty
cycle. Writing new data continuously to the registers
can modulate the brightness of the LEDs to achieve a
breathing effect, blinking, or any other effects that the
user defines.
LED BREATHING CONTROL
By setting the LED bits of the LED Mode Register (03h)
to “1”, the IS31FL3190 will operate in One Shot
Programming mode. In this mode, the LED intensity is
automatically modulated in a breathing cycle,
independently controlled by T0~T4. T0 is an offset time
period which runs only once at the start of the cycle.
The full cycle is T1 to T4 (Figure 6). The maximum
output current can be adjusted by the PWM Register
(Table 8, 04h) in 128 steps.
Figure 6 Breathing Timing
SEMIAUTOMATIC BREATHING
By setting the LED bits of the LED Mode Register (02h)
to “1” and the RM bit of the Breathing Control Register
(01h) to “1”, the ramping function is enabled. HT is the
time select bit. When HT bit is set to “0”, T2 will be
held forever, and the LED will remain at the
programmed maximum intensity. When HT bit is set to
“1”, T3 will continue and T4 will be held, causing the
LED to complete one breathing cycle and then remain
off.
SHUTDOWN MODE
Shutdown mode can either be used as a means of
reducing power consumption or generating a flashing
display (repeatedly entering and leaving shutdown
mode). During shutdown mode all registers retain their
data.
SOFTWARE SHUTDOWN
By setting SSD bit of the Shutdown Register (00h) to
“1”, the IS31FL3190 will operate in software shutdown
mode, wherein they consume only 3.5μA (typ.) current.
When the IS31FL3190 is in software shutdown mode,
all current sources are switched off.
HARDWARE SHUTDOWN
The chip enters hardware shutdown mode when the
SDB pin is pulled low.
