ICL8211CTY Intersil Corporation, ICL8211CTY Datasheet - Page 14

• Manufacturer Part Number: ICL8211CTY
• Description: Programmable Voltage Detectors
• Manufacturer: Intersil Corporation

application shown, the first ICL8212 is used as a zero cross-
ing detector. The output circuit consisting of R
results in a slow output positive ramp. The negative range is
much faster than the positive range. R
teresis so that under all circumstances the second ICL8212
is turned on for sufficient time to discharge C
stant of R
the desired output polarities for low and high input frequen-
cies, either an ICL8211 or an ICL8212 may be used as the
output driver.
This circuit is sensitive to supply voltage variations and
should be used with a stabilized power supply. At very low
INPUT
R
R
V+
2
3
INPUT
1.15V
1.15V
A
B
C
R
R
1
R
1
4
1
7
R
C
FIGURE 37. SWITCH BOUNCE FILTER
100
2
3
C
1
Is much greater than R
1
2
3
4
ON TIME #2
ICL8212
1
2
3
4
R
3
ICL8211
ICL8212
OR
8
7
6
5
4
5
C
and R
FIGURE 36. FREQUENCY LIMIT DETECTOR
8
7
6
5
2
R
. Depending upon
4
A
3
. The time con-
6
TIME CONSTANT R
VARY R
VARY R
C
3
provide hys-
2
, R
R
ICL8211, ICL8212
5
4
1
4
and C
R
FOR OPTION ZERO CROSSING DETECTION
TO SET DETECTION FREQUENCY
L
R
6
V+
V
O
7-174
2
1
2
3
4
3
C
frequencies the output will switch at the input frequency.
Switch Bounce Filter (Figure 37)
Single pole single throw (SPST) switches are less costly and
more available than single pole double throw (SPDT) switches.
SPST switches range from push button and slide types to cal-
culator keyboards. A major problem with the use of switches is
the mechanical bounce of the electrical contacts on closure.
Contact bounce times can range from a fraction of a millisecond
to several tens of milliseconds depending upon the switch type.
During this contact bounce time the switch may make and
break contact several times. The circuit shown in Figure 37 pro-
vides a rapid charge up of C
500k
56k
2
FIGURE 38. LOW VOLTAGE POWER SUPPLY DISCONNECT
< R
OFF
ICL8212
ON
4
C
2
R
7
C
1
2
3
4
3
8
7
6
5
F
ICL8212
INDETERMINATE
BELOW F
O
R
B
7
FREQUENCY
C
3
O
8
7
6
5
1
1
2
3
4
to close to the positive supply
3.9k
4.7k
ICL8211
ICL8212
OR
#3
8
7
6
5
REFERENCE
R
ON
OFF
OUTPUT
6
OUTPUT
LM199
V-