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UM10
729
Al
l i
n
for
m
at
ion
pr
ovi
ded
in
this
do
cum
ent i
s
sub
jec
t to
leg
a
l d
is
c
la
im
er
s.
© N
XP
Sem
ic
ondu
ctor
s
B.V
. 2017.
Al
l r
ig
h
ts
r
e
s
er
v
ed.
User m
a
nu
al
Rev
. 2 — 1 A
ugu
st 2
017
12 o
f 24
N
X
P Semi
conductor
s
UM10729
PCA9
955
A/B
demon
s
tr
at
ion
b
o
ard
OM13
483
Fig 6.
PCA9955A/B demo board schematic (part B)
aaa-013944
4-white and 4-RGB LEDs connect to PCA9955A/B 16-channel outputs
(The LEDs supply voltage can be selected either in3.3V/+5V or external up to +20V)
External voltage input for LED supply
(Less or equal 20V and J13 is open)
RGB4
(R)
(G)
(B)
LED13 short test
LED15 short test
LED14 short test
LED12 open test & ouput
current measurement
LED13 open test & ouput
current measurement
LED14 open test & ouput
current measurement
Notes:
Vf = 3.2V for White LED
Vf = 2.1V for Red LED
Vf = 3.2V for Green LED
Vf = 3.2V for Blue LED
Open/Short test only available for
first four channels LED[0:3] and
last four channels LED[12:15]
LED voltage select:
OPEN: use external voltage
1-2: in3.3V
2-3: in5V
LED15 open test & ouput
current measurement
LED12 short test
RGB4
(R)
(G)
(B)
RGB4
(R)
(G)
(B)
LED3 open test & ouput
current measurement
LED0 short test
RGB4
(R)
(G)
(B)
LED1 short test
LED3 short test
LED2 short test
LED0 open test & ouput
current measurement
LED1 open test & ouput
current measurement
LED2 open test & ouput
current measurement
These serial resistors R23-R38 can change to
non-zero value for voltage switch PCA9955A/B
devices to adjust LED output current
LED0 + LED1
LED1+ LED2
LED[0:15]
+3.3V
+5V
LED0
LED1
LED2
LED3
LED4
LED5
LED6
LED7
LED8
LED9
LED10
LED11
LED12
LED13
LED14
LED15
LED[0:15]
+3.3V
+5V
C21
0.1nF
R29
0 ohm
J13
1
2
3
J25
1
2
R34
0 ohm
J26
1
2
R28
0 ohm
J31
1
2
RGB_LED3
LRTB_G6SF
A1
C2
A2
A3
C3
C1
R33
0 ohm
C11
0.1nF
R27
0 ohm
R32
0 ohm
C12
0.1nF
J12
1
2
J23
1
2
R31
0 ohm
C9
0.1nF
R23
0 ohm
WHT_LED3
LW E67C
J21
1
2
C16
0.1nF
WHT_LED4
LW E67C
R25
0 ohm
J15
1
2
RGB_LED1
LRTB_G6SF
A1
C2
A2
A3
C3
C1
C17
0.1nF
C13
0.1nF
C18
0.1nF
C14
0.1nF
R38
0 ohm
J27
1
2
J14
1
2
C8
10 uF
C15
0.1nF
RGB_LED2
LRTB_G6SF
A1
C2
A2
A3
C3
C1
C10
0.1nF
R37
0 ohm
RGB_LED4
LRTB_G6SF
A1
C2
A2
A3
C3
C1
C22
0.1nF
J22
1
2
R36
0 ohm
J18
1
2
J16
1
2
C23
0.1nF
R35
0 ohm
R24
0 ohm
J29
1
2
J17
1
2
R26
0 ohm
C24
0.1nF
J28
1
2
WHT_LED1
LW E67C
C19
0.1nF
J19
1
2
J24
HEADER 2
1
2
J30
1
2
R30
0 ohm
WHT_LED2
LW E67C
J32
1
2
C20
0.1nF
J20
HEADER 2
1
2