pt8a2621w Pericom Technology Inc, pt8a2621w Datasheet - Page 5

• Manufacturer Part Number: pt8a2621w
• Description: Pir Sensor Light Switch Controller
• Manufacturer: Pericom Technology Inc

PT0091(11/03)
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Functional Descriptions
The PT8A2611 and PT8A2621 are CMOS LSI chips designed
for automatic PIR lamp control. They can operate in 2-wire
configuration for triac applications or in 3-wire configuration
for relay applications.
The PIR sensor detects infrared power variations caused by
motion of a human body and transfer to a voltage variation. If
the PIR output voltage variation conforms to criteria, the lamp
is turned on for an adjustable duration. The PT8A2611 (or
2621) offers three operating modes (ON, AUTO, OFF) which
can be set through a MODE pin. When the device is working
in AUTO mode, the user can override the mode to switch it to
TEST mode or manual ON mode, or return to the AUTO mode
by switching power switch.
Figure 3. CDS Input Circuit
Figure 1. System Oscillator
Table 1. CDS Pin Function
HIGH
LOW
CDS
R
C
S
S
Rp
V
200P
CC
560K
CDS
CDS
OSCS
Day Time
Status
Night
Schmitt
Driver
PT8A2611
/2621
CDS
PT8A2611/2621
Control
Circuit
Disabled
Enabled
PIR
5
OSCS and OSCD Pins
OSCS is a system oscillator I/O pin connected to an external
RC to generate system frequency of 16kHz. OSCD is an output
timing oscillator I/O pin. It
obtain the desired turn-on duration by selecting various val-
ues of RC or using a variable resistor.F
OSCD pin, output timing can be caculated as the formula:
CDS Input Circuit
CDS is a CMOS schmitt trigger input pin. It is used to distin-
guish between day time and night time. When the input volt-
age of CDS is high the PIR input is enabled, when CDS low the
PIR input disabled. The input disable-to-enable debounce
time is 5 seconds. Connect this pin to V
The CDS input is ignored by PT8A2611when the TRIAC out-
put is active, however, PT8A2621
anytime.
CDS
Figure 2. Output Timing Oscillator
Figure 4. CDS Enable Debounce
PIR
Enable
PIR Sensor Light Switch Controller
T
D
= 21504/F
R
C
D
D
OSCD
OSCD
抯
Disable
T
connected to an external RC to
D
= 21504 / F
抯
PT8A2611
PT8A2611/2621
/2621
CDS can not be ignored
OSCD
< 5s
CC
is the frequency of
Data Sheet
when not using it.
OSCD
> 5s
Enable
Ver:3