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PT8A2651
PIR Sensor Light Switch Controller
Features
Description
The PT8A2651 is a CMOS LSI chip designed for
automatic PIR lamp control. The chip is equipped with
operational amplifiers, a comparator, timer, a zero
crossing detector, control circuit, a voltage regulator, a
system oscillator, and an output timing oscillator.
Its PIR sensor detects infrared power variations
induced by the motion of a human body and transforms
it to a voltage variation. If the PIR output voltage
variation conforms to the criteria (refer to the functional
description), the lamp is turned on with an adjustable
duration. The PT8A2651 offers three operating modes
(ON, AUTO, OFF) which can be set through the MODE
pin. While the chip is working in the AUTO mode the
user can override it and switch to the quickly install
mode or manual ON mode or return to the AUTO mode
by switching the power switch. The chip is enclosed in a
16 pin SOIC.
Operating voltage: 5V (Typical)
Average supply current: 120µ (Typical)
A
On-chip regulator
Build-in noise rejection circuit
16KHz system oscillator
Adjustable output duration
Override function
ON/AUTO/OFF selectable by MODE pin
Auto-reset with ZC signal disappearing over 3
seconds
Output positive pulses to drive triac
CDS to enable/disable output
40 second warm-up
Quick check mode for installation
Low cost SOIC-16 package
Pin Configuration
12-07-0006
1
PT0219-1
07/06/12
PT8A2651
PIR Sensor Light Switch Controller
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Pin Description
Pin No.
1
2
3
4
5
6
Pin Name
VSS
TRIAC
OSCD
OSCS
ZC
CDS
I/O
I
O
I/O
I/O
I
I
Ground
TRIAC drive to output two pulses, active positive pulse.
Output timing oscillator. with an external RC to adjust output duration.
System oscillator. with an external RC to set the system frequency. The system frequency
=16KHz for normal application.
Schmitt input for AC zero crossing detection
CDS is connected to a CDS voltage divider for daytime/night auto-detection. Low input to
this pin can disable the PIR input. CDS is a schmitt trigger input with 5-second input
debounce time.
Operating mode selection input:
VDD: TRIAC is always ON
VSS: TRIAC is always OFF
Open: Auto detection, outputs 31.25Hz square wave
Positive power supply
Regulated voltage output The output voltage is about 3.6V with respect to VSS.
Chip reset input, active low
Non-inverting input of OP1
Inverting input of OP1
Output of OP1
Non-inverting input of OP2, internal 1.8V default.
Inverting input of OP2
Output of OP2
Pin Description
7
8
9
10
11
12
13
14
15
16
MODE
VDD
VEE
RSTB
OP1P
OP1N
OP1O
OP2P
OP2N
OP2O
I/O
I
O
I
I
I
O
I
I
O
Block Diagram
Figure 1 Block Diagram
12-07-0006
2
PT0219-1
07/06/12
PT8A2651
PIR Sensor Light Switch Controller
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Maximum Ratings
Storage Temperature ................................................................................... -40oC to +125oC
Ambient Temperature with Power applied...............................................-20oC to +70oC
Supply Voltage to Ground Potential (Input & V
CC
Only).....VSS-0.5V toVDD+0.5V
Supply Voltage to Ground Potential (Onput & D/O Only)..VSS-0.5V toVDD+0.5V
DC Input Voltage .............................................................................................-0.5V to +6.0V
DC Output Current ...................................................................... 20mA
Power Dissipation ......................................................................................................... 500mW
Note:
Stresses greater than those listed under MAXIMUM
RATINGS may cause permanent damage to the
device. This is a stress rating only and functional
operation of the device at these or any other condi-
tions above those indicated in the operational sec-
tions of this specification is not implied. Exposure
to absolute maximum rating conditions for extended
periods may affect reliability.
Recommended operation conditions
Sym
VDD
V
IH
V
IL
F
SYS
T
A
Parameter
Operating Voltage
“H” Input Voltage
“L” Input Voltage
System Oscillator Frequency
Operating temperature
Test Conditions
VDD
Conditions
-
-
-
-
-
-
ROSCS=430K
5V
COSCS=180P
-
-
Min
4.75
0.8
-
12.8
-20
Typ
5.0
-
-
16
25
Max
6.0
-
0.2
19.2
70
Unit
V
VDD
VDD
KHz
°
C
Electrical Characteristics
Sym
V
TH1
V
TL1
V
TH2
V
TL2
V
TH3
V
TL3
V
TH4
V
TL4
I
IH
I
IL
I
IHRSTB
I
OH
I
OL
Parameter
CDS “H” Transfer Voltage
CDS “L” Transfer Voltage
ZC “H” Transfer Voltage
ZC “L” Transfer Voltage
OSCS “H” Transfer Voltage
OSCS “L” Transfer Voltage
OSCD “H” Transfer Voltage
OSCD “L” Transfer Voltage
High level leakage current (ZC,CDS)
Low level leakage current (ZC,CDS)
RSTB Input high level current
Output source current( TRIAC)
Output sink current(TRIAC)
Test Conditions
VDD
Conditions
5V
-
5V
5V
-
5V
5V
-
5V
5V
-
5V
V
IH
=4.5V
5V
5V
5V
5V
5V
V
IL
=0.5V
V
IH
=4.5V
V
OH
=4.0V
V
OL
=0.5V
Min
3.0
0.9
2.6
1.1
2.7
0.8
2.7
0.8
-1
-1
-1
-18
3
Typ
3.3
1.2
2.9
1.4
3
1
3
1
-
-
-
-
-
Max
3.6
1.5
3.2
1.7
3.3
1.2
3.3
1.2
1
1
-5
-
-
Unit
V
V
V
V
V
V
V
V
A
A
A
mA
mA
Voltage regulation circuit
Sym
VEE
OP2P
V
O
V
LDR
Parameter
Regulator Output Voltage
Non-inverting input of OP2
Line regulation
Load regulation
VDD
5V
5V
-
5V
Test Conditions
Conditions
No load
No load
4.5VDD5.5V, I
L
=1mA
0.5mA
I
L
2mA
Min
3.24
1.62
-
-
Typ
3.6
1.8
30
60
Max
3.96
1.98
50
100
Unit
V
V
mV
mV
12-07-0006
3
PT0219-1
07/06/12
PT8A2651
PIR Sensor Light Switch Controller
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Operational amplifier and windows comparator
Parameter
BW
V
H
V
L
Description
3dB band width
Threshold of windows
comparator
Test conditions
-
VDD=5V
VDD=5V
Min
10
2.2
0.8
Typ
-
2.52
1.08
Max
-
2.8
1.3
Unit
KHz
V
V
Frequency of oscillator and timing of ZC and trigger output
Parameter
F
MODE
T
DZT
T
TPW
Description
Oscillator frequency/512
Delay time from ZC to TRIAC
TRIAC Pulse Width
Test conditions
VDD=5V,
RS=430K ,CS=180P
Min
25
1.16
50
Typ
31.25
1.45
62.5
Max
37.5
1.74
75
Unit
Hz
ms
s
Power Dissipation
Sym
I
CC
Description
Power supply current
Test Conditions
VDD=5V, R
S
=430K ,C
S
=180P,
R
D
=2M, C
D
=104, other Input Pins=VSS,
all outputs float.
Min
-
Typ
120
Max
200
Unit
A
12-07-0006
4
PT0219-1
07/06/12
PT8A2651
PIR Sensor Light Switch Controller
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Functional Description
VEE
VEE supplies power to the analog front end circuit, it is about a stable 3.6V with respect to VSS normally.
OSCS
OSCS is a system oscillator input pin. System frequency of 16KHz can be generated when connecting to an external RC, see
figure 2 (R=430K, C=180pf).
TD=23552/FOSCD
RS
VTH3
430k
OSCS
-
+
-
VTL3 +
RD
OSCD
+
CD
VTH4
-
+
-
VTL4 +
+
+
+
CS
180P
PT8A2641/2/5/6/7/8
Figure 2 System oscillator
PT8A2641/2/5/6/7/8
Figure 3 Output timing oscillator
OSCD
OSCD is input pin of timing oscillator. It’s connected to an external RC to obtain the desired output timer. Variable output
turn-on duration can be achieved by selecting various values of RC or using a variable resistor, see figure 3.
Note:
The minimum resistor should be low enough to 2K in order to provide adjustable range about 1000 times between min
and max timer.
Formula for timer calculation as below (VH=3/5VCC,VL=1/5VCC)
Charging time of Capacitor: Tc =R*C*ln[(VCC-VL)/(VCC-VH)]=0.6931*R*C
Ideal calculation formula: TD =23552*Tc.
5s
12minutes(720s)
R (C=223)
15K
2000K
Error compared to ideal formula
±
15%
±
5%
3s
5s
25s
R (C=104)
2K
3K
15K
Error compared to ideal formula
±
100%
±
80%
±
15%
Note:
It is recommended that C is more than 103 in order to guarantee not too bad linearity.
TRIAC
TRIAC to drive (active positive pulse) TRIAC. The output active duration is controlled by the OSCD oscillating period.
CDS
With a schmitt trigger input structure, CDS is used to distinguish lighteness. Putting a cds component in a resistor divider, if
light is weak enough, CDS is high the PIR input is active. Oppositely, the CDSO will be inactive when CDS is low. The input
debounce time from inactive to active is 5 seconds. CDS should be pulled high without using this function. The input of CDS will
be ignored once the output is active.
CDS
Status
CDSO
LOW
Day Time
inactive
HIGH
Night
active
5000s
3000K
±
5%
RW
CDS
CDS
<5s
>5s
CDS CDSO enable
disable
enable
Figure
4
4
CDS input interface and enable debounce
debounce
CDS input interface and enable
Figure
12-07-0006
5
PT0219-1
07/06/12
微控制器 MCU
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