NCS36000
6
Figure 7. Timing Diagram for Dual−Pulse Mode Detection
OUT
120 T
CLK
3T
CLK
1T
CLK
OP 2_O
V
H
= 2,5V
V
L
= 1,7V
V
M
= 2,1V
T
SP
< 3T
CLK
T
SP
> 3T
CLK
T
DP
< 360 T
CLK
T
SP
> 3T
CLK
LED
OUT
OP2_O
OP2_N
OP1_O
OP1_N
OP1_P
VREF
VSS
xLED_EN
nc
VDD
OSC
MODE
1
2
3
4
5
6
7
14
13
12
11
10
9
8
G
D
Sensor dependent
components
Power Supply /
AC to DC Rectifier
R1
R2
R3
R4
C1
C2
C3
C4
C6
C5
R5
D1
R7
C7
J1
J2
R6
Microcontroller
Figure 8. Typical Application Diagram Using NCS36000
R1 = 10 k
W
C1 = 33
m
F
J1 (Jumper for xLED_EN)
R2 = 560 k
W
C2 = 10 nF
J2 (Jumper for Mode Select)
R3 = 10 k
W
C3 = 33
m
F
D1 (LED)
R4 = 560 k
W
C4 = 10 nF
R5 = 43 k
W
C5 = 100 nF
R6 = 1 k
W
C6 = 100 nF
R7 = 220 k
W
C7 = 100 nF
9. R1, C1, R2, C2, R3, C3, R4, C4 setup bandpass filter characteristics. With components as shown above the passband gain is approximately
70 dB with the 3 dB cutoff frequency of the filter at approximately 700 mHz and 20 Hz.
10. R4 can be replaced by a potentiometer to adjust sensitivity of system. Note dynamically changing R4 will also change the pole location for
the second amplifier.
11. R5 and C5 are sensor dependant components and R6 may need to be adjusted to guarantee the AMP 1 IN parameter outlined within the
Operating Ranges section of this document.
12. R7 and C7 may be adjusted to change the oscillator frequency. R7 may not be smaller than 50 k
W
.
