PT8A261 Datasheet, PDF (6/13 Pages) Pericom Semiconductor Corporation – PIR Sensor Light Switch Controller

Data Sheet
PT8A261/262
PIR Sensor Light Switch Controller
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MODE
MODE is a tri-state input pin for operation mode selection.
See the following table 3.
Override Control: The term “override” refers to the change of
operating mode by switching the power switch twice within 3
seconds. When the chip is working in the AUTO mode (MODE
pin openned), the output is activated by a valid PIR trigger
signal and the output active duration is controlled by the OSCD
oscillation period. The lamp can be switched to ON from the
AUTO mode by either switching the MODE pin to V_CC or
switching the power switch twice within 3 seconds. The de-
vice can be toggled from ON to AUTO by switching the power
switch twice within 3 seconds again (override operation).
If the chip is overridden to ON and there is no further override
operation, it will return to AUTO automatically after an inter-
nal preset ON time duration (8 hours).
The override operation will cause the lamp flash (for TRIAC
version only). It will flash 3 times at 1Hz rate when changing
AUTO mode to other mode, and flash 3 times at 2Hz rate when
returning to AUTO mode. But no flash if mode is changed by
switching the MODE switch. See Figure 7 for override timing.
Table 3. Operation Modes by MODE Pin
MODE
Status
Operation
Mode
Description
V_CC
ON
Output is always ON: RELAY pin sends high level for relay driving; TRIAC pulse train output is
synchronized by ZC for triac driving.
GND
OFF
Output is always OFF: RELAY pin sends low level for relay driving; TRIAC pin sends high level
for triac driving.
Open
AUTO
Outputs remain in the OFF state until activated by a valid PIR trigger input signal. When working
in the AUTO mode, the device allows override control by switching the ZC signal.
Figure 7. Override Timing
Operating Mode
AUTO
ZC
flash
ON
flash
AUTO
flash
ON
8 hours
Flash is only for TRIAC version
flash
AUTO
RST Pin
Figure 8. RST Application Example
RST is used to reset the device. It is internal pull-high and
active low. The use of C_RST can extend the power-on initial
time. If the RST pin is openned (without CRST), the initial
time is 40 seconds. See Figure 8.
REST
V_CC
RST
CRST
GND
PT0075(04/03)
6
Ver:5