IS31FL3194
Integrated Silicon Solution, Inc. – www.issi.com 14
Rev. B, 08/04/2017
TYPICAL APPLICATION INFORMATION
GENERAL DESCRIPTION
IS31FL3194 is a 3-channel LED driver which
features two-dimensional auto breathing mode. It has
Pattern Mode and Current Lever Mode for RGB
lighting effects.
POWER ON SEQUENCE
IS31FL3194 provides a power-on reset feature that
is controlled by VBAT supply voltage. When the
VBAT supply voltage exceeds 2.4V (TBD), the
internal circuit starts to work. The reset signal will be
generated to perform a power-on reset (POR)
operation, which will reset all control circuits and
configuration registers until the internal power
voltage become stable.
Before SDB pull high, the I2C operation is allowed.
The SDB rising edge will reset the I2C bus.
Figure 7 SDB Pin Sequence
Note 1: I2C operation is allowed when SDB is low.
Note 2: There should be no I2C operation 10µs before and after
SDB rinsing edge.
In some case, like a mouse, when plug-out and
quickly plug-in back the USB power, the LED will
flicker for a very short time. The reason is the power
is not lower than the POR voltage point (usually
lower than 2.2V), and the device still stores the
previous setting data, if user pull-up the SDB high
when power up, following with the initial operation,
the LED will be ON between SDB rising edge and
Current Level initial effective, to avoid this, as above
figure, a writing to 01h is recommended to shutdown
the chip before pull-high the SDB pin.
CURRENT LEVEL MODE
There are four programmed current bands can be set
by the Current Band Register (03h). It is used to set
the global maximum of each output current, I
MAX
.
By setting the OUTx bits of the Operating Configure
Register (01h) to “0”, the corresponding OUTx will
operate in Current Lever Mode. The Current Lever
Registers (10h, 21h, 32h) are active and can
modulate LED brightness of each output with 256
steps independently. For example, if the data in
Current Lever Register is “0000 0100”, then the
current lever is the fourth step, with a current level of
4/256.
In Current Lever Mode, user doesn’t need to turn on
the CEx of 1Ch/2Ch/3Ch, a new value must be
written to the Current Lever registers to change the
output current. Writing new data continuously to the
registers can modulate the brightness of the LEDs to
achieve a breathing, blinking, or any other effects
that the user defines.
PATTERN MODE
By setting the OUTx bits of the Operating Configure
Register (01h) to “1”, the corresponding OUTx will
operate in Pattern Mode. In Pattern Mode, the timing
characteristics for output current – current rising (T1),
holding (T2), falling (T3) and off time (TS, TP, T4),
can be adjusted individually so that each output can
independently maintain a pre-established pattern
achieving mixing color breathing or a single color
breathing without requiring any additional interface
activity, thus saving valuable system resources.
PATTERN COLOR SETTING
In Pattern Mode, the LED color is defined by
PxCOLy_Oz (x,y,z= 1,2,3) bits in Color Setting
Registers (10h~18h, 20h~28h, 30h~38h). There are
3 RGB current combinations to generate 3
pre-defined colors for display. More than one of the 3
pre-defined colors can be chosen by setting Cex bits
in Color Enable Register (1Ch/2Ch/3Ch). When Cex
is set, the color x is allow to be displayed in current
pattern.
Table 20~22 show the registers for each mode, for
example, in the Current Level Mode, the current lever
register is 10H for OUT1, 21H for OUT2, 32H for
OUT3, in Single mode and pattern mode, Pattern 1
has 3 current level registers and enabled/disabled by
Cex.
Table 20 Color Register Of Single Mode
Mode
Color
Enable
P1
OUT1
P2
OUT2
P3
OUT3
Single
Mode
Pattern
Mode
CE1 10H 21H 32H
CE2 13H 24H 35H
CE3 16H 27H 38H
Current
Level
Mode
- 10H 21H 32H
