WT8076

Passive Infrared (PIR) Controller

Version 1.0 25-May-1995

Weltrend Semiconductor Inc.

2F, No. 24, Industry E. 9

RD., Science-Based Industrial Park, Hsin-Chu, Taiwan

TEL:886-3-5780241 FAX:886-3-5794278.5770419

eltrend

GENERAL DESCRIPTION

The WT8076 is a PIR controller IC which integrates amplifier, window detector and light control
functions. The light can be controlled by a Relay or Triac with adjustable delay time. A CDS interface is
provided to sense day time and night time. A walk-test fuction helps user while setting up the light set.
The line remote control function can switch the light set between auto mode and always-on mode.

FEATURES

Adjustable detection range

Adjustable delay time

CDS interface to differentiate night time and day time

Walk-test function

Line remote control to switch auto mode and always on mode

Relay or Triac output

High noise immunity

Low power consumption ( operating 500uA, standby 130uA, Typ. )

PIN ASSIGNMENT

UOU1

NII1

II1

VREF

GND

TCI

UOU2
NII2
II2
CDS
VDD
ZCD
RELAY
TRIAC

1
2
3
4
5
6
7
8

16
15
14
13
12
11
10

1
2
3
4
5
6
7
8

16
15
14
13
12
11
10

GND

TCI

TRIAC

RELAY

ZCD
VDD

VREF
II1
NII1
UOU1
UOU2
NII2
II2
CDS

UOU1

NII1

II1

VREF

GND

TCI

UOU2
NII2
II2
CDS
VDD

ZCD
RELAY

TRIAC

1
2
3
4
5
6
7
8
9

18
17
16
15
14
13
12
11
10

ND
WK

WT8076N16P1

WT8076S16P1

WT8076N18P2

Ordering Information

PART No.

PACKAGE

WT8076N16P1

16 Pin P-DIP

WT8076S16P1

16 Pin SOIC

WT8076N18P2

18 Pin P-DIP

WT8076

Passive Infrared (PIR) Controller

Weltrend Semiconductor Inc.

eltrend

PIN DESCRIPTION

Pin No.

N16P1

S16P1

N18P1

Name

Descriptions

UOU1

Output of the first stage OP amplifier.

NII1

Non-inverting input of the first stage OP amplifier.

II1

Inverting input of the first stage OP amplifier.

VREF

Reference voltage output.

GND

Ground.

Time Base. A RC oscillaror is connected on this pin.
Typical frequency is 30kHz.

---

No connection.

TCI

Time control input. A RC oscillator is connected on this
pin. It controls the delay time of the light.

TRIAC

Triac control pin. Active low.

RELAY

Relay control pin. Active hight.

ZCD

Zero-crossing input. It detects the zero-crossing point of
the AC line. The ouput of TRIAC pin is synchronous to this
pin.

WKT

Walk-Test function enable/disable. Internal pull low. The
walt-test function is disbled when this pin is high level.

Night and day detection enable/disable. Internal pull low.
The night-and-day detection is disbled when this pin is
high level.

VDD

Power supply.

CDS

Connect a photo-sensitive resistor to detect night time
and day time. If the input level is lower than 1.2V, it is
day time. If the input level is higher than 1.9V, it is night
time.

II2

Inverting input of the second stage OP amplifier.

NII2

Non-inverting input of the second stage OP amplifier.

UOU2

Output of the second stage OP amplifier.

* WT8076N16P1 and WT8076S16P1 : Walk-Test and Night&Day function is always enabled.

WT8076

Passive Infrared (PIR) Controller

Weltrend Semiconductor Inc.

eltrend

BLOCK DIAGRAM

1.25V

1.95V

OSC

CONTROL

LOGIC

Window
Detector

3.2V

REF.

VOLTAGE

UOU2

II2

UOU1

II1

NII1

VREF

VDD

System Clock

WKT

ZCD

RELAY

TRIAC

TCI

CDS

NII2

PIR

CDS

WT8076 Block Diagram

1.6V

WT8076

Pulse Width

Detector

Counter

WT8076

Passive Infrared (PIR) Controller

Weltrend Semiconductor Inc.

eltrend

FUNCTIONAL DESCRIPTION

PIR Amplifier
The amplifier has two stages, please see block diagram . The voltage gain and frequency response can
be adjusted by the external resisters and capacitors.

Window Detector
If the amplified PIR signal is between V

(1.95V) and V

(1.25V), the signal is ignored and the output of

the window detector is low level. If the amplified signal is larger than V

or smaller than V

, the output of

the window detector is high level.

Pulse Width Detector
The pulse width detector detects the pulse width of the window detecter's output. If the pulse width is
less than 90ms ( f

= 30kHz ), this pulse is ignored. If the pulse width is larger than 90ms, it will trigger

the light to turn on.

Light Control
The light is controlled by the RELAY pin or TRIAC

pin. The RELAY pin outputs a high level when a valid

pulse is detected. The delay time is determined by the RC on the TCI pin. If another valid pulse
occurs during the delay time, the delay time will be reset. Fig. 1 shows the relationships.
The TRIAC pin is an open drain NMOS output. The turn on angle is about 24

1.95V

1.25V

UOU2 Pin

Signal on

<90ms

>90ms

<90ms

90ms

Window detector
output

RELAY pin

Pulse width
detector output

TRIAC pin

ZCD pin

Figure.1 Timing Relationship

delay time

WT8076

Passive Infrared (PIR) Controller

Weltrend Semiconductor Inc.

eltrend

CDS Interface
The CDS interface detects the level on the CDS pin. If the level is higher than 1.95V, it is night time.
If the level is lower than 1.25V, it is day time.

Operating Modes
The operating modes of WT8076 are:
(1) Auto mode:
The light will turn on when a valid pulse is detected in the night time.
(2) Always on mode:
If the ND pin is low level, the light is always on in the night time. When it detects day time, the
light will be turn off, and back to auto mode.
If the ND pin is high level, the light is always on.
(3) Walk-test mode:
The walk-test mode is active after the power is on. This mode is same as the auto mode except
the CDS is ignored. That is, the light will be turn on when a valid pulse is detected no matter it is
night time or day time.

Remote Control
To switch auto mode between always on mode, the WT8076 detects the zero crossings of the AC line. If
the line switch OFF and ON one time in 3 seconds, it toggles the auto mode and always on mode.

Time Base
The RC oscillator on the TB pin generates the system clock. The frequency is 30kHz typically (R
=30Kohm, C=1000pF) .
The following parameters are decided by the time base :
(1) Trigger angle of the TRIAC (24

, if time base is 30kHz).

(2) Pulse width (90ms,if time base is 30kHz).
(3) Remote control switch time.
(4) Disable PIR after the light is off.
(5) Total walk-test time.

The RC oscillator on the TCI pin sets the delay time. Figure 2 shows the relationship betwteen delay
time and the R ( C=1000pF).

WT8076

Passive Infrared (PIR) Controller

Weltrend Semiconductor Inc.

eltrend

ELECTRICAL CHARACTERISTICS

Absolute Maximum Ratings

Item

Symbol

Ratings

Uit

supply voltage

Input Voltage

-0.5 to V

+0.5

Operating Temperature

OPR

-25 to 70

StorageTemperature

STG

-65 to 150

Power Dissipation

500

Note: Stress above those conditions listed may cause permente damage to the device.

Electrical Characteristics

( VDD=5.0V, TA=25

C )

Item

Symbol

Test Condition

Min

Typ

Max

Unit

Operating Voltage

4.5

5.5

Standby Current

DDS

130

600

Operating Current

DDO

No load on output.

500

1000

Reference Voltage

REF

3.2

3.4

Ripple of VREF

0.5

Time Base Frequency

R=30K,C=1000p

kHz

CDS V

T+

1.95

2.1

CDS V

T-

T+

1.25

TCI Frequency

TCI

50k

TRIAC pin Sink Current

= 1.5V

RELAY pin Source Current

= 3.5V

Characteristics of OP Amplifier

( VDD=5.0V, TA=25

C )

Item

Symb

Test Condition

Min

Typ

Max

Unit

Input Bias Current

bias

Input Offset Current

offset

Input Offset Voltage

offset

Output Swing Voltage

swing

=470K

Output Source Current

source

Output Sink Current

sink

3.5

Differential Gain

100

Commom Mode Rejection Ration

CMRR

Power Supply Rejection Ration

PSRR

WT8076

Passive Infrared (PIR) Controller

Weltrend Semiconductor Inc.

eltrend

TYPICAL APPLICATION CIRCUIT

UOU1 NII1 II1 VREF GND TB TCI TRIAC

UOU2 NII2 II2 CDS VDD ND WKT ZCD RELAY

WT8076

560K

0.047u

Lamp

ZD1
12V

ZD2

5.6V

220u
25V

2.4K

470K

100u
10V

R10

R11

1N4001

C11

C10

C12

R12

0.47u/250V

R13
100

0.047u
250V

C13

110V

820K

15K

33u

0.1u

100u

C1
1000p

30K

20K

1000p

47K

0.01u

PIR

47u

15K

47u

CDS

51K

RELAY

R14
5.6K

WT8076N18P1 Application Circuit For RELAY Output

FUSE

1N4148

Note:
(1) To adjust delay time, change R1 value. ( R1=20K, delay time is about 10 sec )
(2) For different CDS, R8 value should be adjusted.

WT8076

Passive Infrared (PIR) Controller

Weltrend Semiconductor Inc.

eltrend

Note:
(1) To adjust delay time, change R1 value. ( R1=20K, delay time is about 10 sec )
(2) For different CDS, R8 value should be adjusted.

UOU1 NII1 II1 VREF GND TB TCI TRIAC

UOU2 NII2 II2 CDS VDD ND WKT ZCD RELAY

WT8076

560K

0.047u

Lamp

ZD1

5.6V

470K

100u
10V

R10

R11

1N4004

C11

C10

R12

0.1u/250V

110V

820K

15K

33u

0.1u

100u

C1
1000p

30K

20K

1000p

47K

0.01u

PIR

C7
47u

15K

47u

CDS

51K

WT8076N18P1 Application Circuit For TRIAC Output

100K

TRIAC

R13

330

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ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: WT8076N18P2