Nellcor NPB-190 Service Manual page 77

VREF
C36
390P
I27 I28
R25
3.32K
R21 R28
3.32K 182K
I32
J1
10 10
5 5
9 9
4 4
8 8
3 3
7 7
2 2
6 6
1 1
11 11
CON_DB9F
035191
+10V
U5
AD822
5 8
+
7
6
-
4
+10V
U12
-5V
13 DG201S
V+
16
15
I30
14
R29
GND V-
1.00M
5 4
-5V
C34 18P
IR/RED
+10V R27
280K VREF VCC
I33
C35
0.047U
8 3
+
1
2 C8
-
U5 4 0.1U I35
AD822 R37
Z5U
511K 2 2
I34
1 1
C37
-5V
0.047U 3 3
Q10
MPSA56S
VREF
2 2
3 3
MPSA56S
R22
10.0K
RSENS Q1
MPSA06S MPSA06S
3 3 3 3
C30 C31 C32 1 1 1 1
100P 100P 100P
2 2 2 2
TP17
R33
R32
10.0
10.0K
VREF
R30
6.04K_0.1%
C9
0.1U
Z5U
VCC
C33
LED DRIVE
R35
0.01U
10.0K
I37
R44
2.74K
VCC U2
6 6 6 VCC 16 1
INH
11 11
A
10 10 I45
B
9 9 14 14
C X
R20
10.0K 12 12 15
XO Y
13 13
I36
X1
4 4 U11
R18 Z
2 2 LT1013S
2.74K Y0
1 1
Y1
1 1
VEE 7 7
Q9
5 5
Z0
3 3 8 8
I39
Z1 VSS
I38
CD4053S
I40
Q2
I42
I51
I43 I44
R36
22.1K
3 3 R24
1 1 100K
Q3
R34
2N3904S TP12
10.0K 2 2
R26
100K
I46
I47
VCC
2 2
C29 Q8
4.7P 1 1 2N3906S R23
+ 3 3
182K
1
6
+
7 R40
8
100K
- TP18
2
-
R19 C39 R39
10.0K 0.1U 20.0K
C40
0.022U
C38 22P
3 3 1 1
CR5 1N914S
3 3 1 1
CR6 1N914S VREF
I50
TP14
R31
40.2K
R38
15.8K
FRONT END LED DRIVE
Front End LED Drive Schematic Diagram (2 of 10)
G_LEDDR
I31
IR/RED
G_PWM2
I48 G_PWM1
R43
182K
R42
100K
TP19
C41 R41
0.1U 20.0K
C42
0.022U
OFF/ON
LEDDIS
I49
VCC
I52
+
3
6
+
5
PHOTOI
4
-
2 U11
-
LT1013S
RSENS
Figure S-4
S-13