IS31FL3731-QFLS2-TR ISSI, IS31FL3731-QFLS2-TR Datasheet - Page 10

• Manufacturer Part Number: IS31FL3731-QFLS2-TR
• Description: LED Lighting Drivers LED Driver
• Manufacturer: ISSI

Specifications of IS31FL3731-QFLS2-TR

• Input Voltage: 2.7 V to 5.5 V
• Operating Frequency: 400 kHz
• Maximum Supply Current: 2.17 mA
• Output Current: 34 mA
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-28
• Minimum Operating Temperature: - 40 C
• Factory Pack Quantity: 2500

IS31FL3731
REGISTER CONTROL
FRAME REGISTER
Table 4 00h ~ 11h LED Control Register
The LED Control Registers store the on or off state of
each LED in the Matrix A and B. Please refer to the
detail information in Table 7.
C
0
1
Figure 8 in Page 10 shows the ordering of C
Table 5 12h ~ 23h Blink Control Register
The Blink Control Registers configure the blink
function of each LED in the Matrix A and B. Please
refer to the detail information in Table 7.
C
0
1
Figure 8 in Page 10 shows the ordering of C
Integrated Silicon Solution, Inc. – www.issi.com
Rev.B, 09/10/2012
X-Y
X-Y
Default
Default
Name
Name
Bit
Bit
LED State Bit
LED off
LED on
Blink Control Bit
Disable
Enable
C
C
X-8
X-8
: C
: C
xxxx xxxx
xxxx xxxx
X-1
X-1
D7:D0
D7:D0
or C
or C
X-16
X-16
: C
: C
X-9
X-9
X-Y
X-Y
.
.
Table 6 24h ~ B3h PWM Register
PWM Registers modulate the 144 LEDs in 256 steps.
The value of the PWM Registers decides the output
current of each LED. The output current may be
computed using the Formula (1):
Where D[n] stands for the individual bit value, 1 or 0,
in location n.
For example: if D7:D0 = 10110101,
I
64.7/R
For example, when R
3.2mA.
LED
Default
Name
is set by the external resistor, R
Bit
EXT
.
I
PWM
I
PWM

= I
I
256
LED
LED
EXT
(2


= 20kΩ, I
n
0
7

+2
0
D
xxxx xxxx
2
+2
D7:D0
[
PWM
n
]
4
+2

LED
2
EXT
5
n
+2
= 64.7/20 =
, I
7
)/256
LED
=
(1)
10