FEATURES:
· Direct Interface with PIR Sensor
· Two-Stage Differential Amplifier
· Amplifier Gain and Bandwidth externally controlled
· Window Comparator and Digital Filter limit Noise
· Triac Output Drive
· Programmable Output Duration Timer
· Selectable Dead Time
· Single or Dual Pulse Detection
· Timing derived from 50Hz/60Hz AC
· Motion Detection LED Indicator
· LS6505 (DIP), LS6505-S (SOIC)- See Figure 1

APPLICATIONS:
Wall and ceiling mounted occupancy sensors providing
energy savings and convenience.

DESCRIPTION (See Figure 2)
The LS6505 is a CMOS integrated circuit, designed for detecting
motion from a PIR Sensor and initiating appropriate responses.

DIFFERENTIAL AMPLIFIER
Each stage of the two stage Differential Amplifier can be set to
have its own amplification and bandwidth. The two inputs to the
first stage allow for single ended or differential connection to PIR
Sensors. This stage can be biased anywhere in its dynamic range.
The second stage is internally biased so that the Window Compar-
ator's lower and higher thresholds can be fixed relative to this bias.

WINDOW COMPARATOR
The Window Comparator provides noise filtering by enabling only
those signals equal to or greater than a fixed threshold at the out-
put of the Differential Amplifier to appear at the output of the
Window Comparator.

COMPARATOR DIGITAL FILTER
The output of the Window Comparator is filtered so that motion
must be present for a certain duration before it can be recognized
and appear as pulses at the Digital Filter output.

SINGLE PULSE / DUAL PULSE MODES
The logic level at the Pulse Mode Select input selects Single Pulse
(SP) or Dual Pulse (DP) mode. The trigger for the Output Duration
Timer is generated by requiring one (SP Mode) or two (DP Mode)
pulses to be present at the Digital Filter output within a specified
time period. SP Mode = 0; DP Mode = 1

OUTPUT DURATION TIMER (See Table 1 and Figure 3)
The timeout is selected by the voltage level at the Timer Control in-
put. The Timer's trigger is generated from pulses at the Digital filter
output. In Auto operation, the Timer controls the On duration of the
Triac output and is retriggerable.

DEAD TIME (See Table 2)
False turn-ons are prevented from occurring by establishing a
Dead Time between the end of the timeout of the Output Duration
Timer and the retriggering of that Timer.

TRIAC OUTPUT
This open drain output turns On when the Output Duration
Timer is triggered. The output drives a Triac gate. With the Out-
put Duration Timer On and a 2.7V P-P 60Hz signal applied to
the AC input, this output produces a negative going pulse in
each half-cycle delayed a nominal 1.2ms from the zero crossing.
There is no more than 150us difference between the zero-
crossing delay of each pulse.

WARNING OUTPUT
This output goes high for 2 sec beginning 7.5 sec before the
Triac output turns off. This signal can be used to trigger an
audible or visual alert.

LED OUTPUT (See Figure 3)
Normally, the status of the LED output is opposite to the Triac
output, but in Auto operation the LED output flashes on for one
second whenever motion is detected.

MODE SELECT
Open = Mode A, Vss = Mode B, V

= Mode C

OPERATION SELECT (See Figure 3, S1)
The 3-state Operation Select input determines the operation of
LS6505 in accordance with the selected Mode as shown below:

Input Mode A Mode B Mode C

(1)

(3)

Open

Auto

Prior Condition

Auto

Vss

Off

(2)

(4)

(1) Momentary application of V

turns on the Triac output and

starts Auto operation. After the Triac output is off for 15
seconds, Auto operation terminates.

(2) Momentary application of Vss turns off the Triac output.
(3) Same as (1) except that Auto operation does not terminate.
(4) Same as (2) except that after the Triac output is off for 8
seconds, Auto operation begins.

PIR SENSOR INTERFACE

November 2002

6505-110602-1

LSI

LS6505

DIFF. AMP. 2 INPUT (-)

DIFF. AMP. 2 OUTPUT

AC INPUT

TRIAC OUTPUT

DIFF. AMP 1 INPUT (-)

DIFF. AMP 1 INPUT (+)

TIMER CONTROL INPUT

DEAD TIME SELECT INPUT

OPERATION SELECT INPUT

PULSE MODE
SELECT INPUT

LED OUTPUT

PIN ASSIGNMENT - TOP VIEW

FIGURE 1

DIFF. AMP. 1 OUTPUT

MODE SELECT INPUT

WARNING OUTPUT

LSI/CSI

LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747 (631) 271-0400 FAX (631) 271-0405

LS6505

A3800

ABSOLUTE MAXIMUM RATINGS:

PARAMETER

SYMBOL

VALUE

UNIT

DC supply voltage

- V

+5.5

Any input voltage

- 0.3 to V

+ 0.3

Operating temperature

-40 to +85

°C

Storage temperature

STG

-65 to +150

°C

ELECTRICAL CHARACTERISTICS:
( All voltages referenced to V

, T

= -40°C to +55°C, 4.5V

5.5V, unless otherwise specified.)

PARAMETER

SYMBOL

MIN

TYP

MAX

UNIT

CONDITIONS

SUPPLY CURRENT:

= 5V

150

200

µA

Triac and LED

= 4.5V - 5.5V

180

240

µA

outputs not loaded

DIFFERENTIAL AMPLIFIERS:
Open Loop Gain, Each Stage G

Common Mode Rejection Ratio CMRR

Power Supply Rejection Ratio PSRR

Output Drive Current

µA

Input Sensitivity

100

µV

= 25°C, with Amplifier

(Minimum Detectable Voltage

Bandpass configuration

to first amplifier when both

as shown in Figure 3

amplifiers are cascaded for
a net gain of 5,000)

Input Dynamic Range

2.5

Diff. Amp 2 Internal

0.4VR

Reference

COMPARATOR:

Lower Reference

THL

- 0.5V

Higher Reference

THH

+ 0.5V

DIGITAL FILTER:
Input Pulse Width

66.3

60Hz operation

(for recognition)

79.6

50Hz operation

OUTPUT DRIVE CURRENT:
Triac

-40

With 3V Triac Gate

Warning: Source Current Iw +

Vo =V

- 0.5V

Sink Current

Iw -

Vo = 0.3V Max

TRIAC OUTPUT TIMING:
Pulse Width

TPW

µs

= 5V, f = 60Hz and

Delay from zero crossover T

1.00

1.2

1.32

2.7V P-P AC input

Delay difference between

ODD

150

µs

f = 60Hz

zero crossovers

AC INPUT IMPEDANCE

270

LED OUTPUT:
Source Current

S+

Vo = V

- 0.5V

Sink Current

S-

Vo = 0.3V

Pulse Width

LPW

0.75

1.25

sec

f = 60Hz

DUAL PULSE MODE:
Time between pulse-pairs

5.125 sec

f = 60Hz

for motion recognition

6505-110102-2

TABLE 1

OUTPUT DURATION TIMER AS A FUNCTION OF TIMER

CONTROL INPUT VOLTAGE

(f = Frequency at AC input)

TABLE 2

DEAD TIME DURATION AS A FUNCTION OF THE

STATE OF DEAD TIME SELECT INPUT

(f = Frequency at AC input)

6505-110102-3

AMP

COMP

DIFF AMP 2
OUTPUT

DIFF AMP 2
INPUT (-)

DIFF AMP 1
OUTPUT

DIFF AMP 1
INPUT (-)

DIFF AMP 1
INPUT (+)

A/D

CONVERTER

OUTPUT
DURATION
TIMER

DIGITAL
FILTER

CONTROL
LOGIC

DEAD
TIME
TIMER

1 SECOND
PULSE GEN

OUTPUT
BUFFER

ZERO CROSS-OVER

DETECT

TIMER
CONTROL
INPUT

OPERATION SELECT
INPUT

PULSE MODE
SELECT INPUT

DEAD TIME
SELECT INPUT

LED OUTPUT

TRIAC OUTPUT

AC INPUT

FIGURE 2. LS6505 BLOCK DIAGRAM

PULSE
SELECT
LOGIC

WINDOW

COMPARATOR

(+V)

(-V)

WARNING OUTPUT

MODE SELECT INPUT

sec

1/16 V

sec

2/16 V

sec

3/16V

sec

4/16 V

2.4

min

5/16 V

3.6

min

6/16 V

4.8

min

7/16 V

min

8/16 V

7.2

min

9/16 V

8.4

min

10/16 V

9.6

min

11/16V

10.8

min

12/16 V

min

13/16 V

14.4

min

14/16 V

16.8

min

15/16 V

min

INPUT VOLTAGE f = 50Hz f = 60Hz UNIT

sec

OPEN

1.2

sec

2.4

sec

INPUT STATE f = 50Hz f = 60Hz UNIT

The information included herein is believed to be
accurate and reliable. However, LSI Computer Systems,
Inc. assumes no responsibilities for inaccuracies, nor for
any infringements of patent rights of others which may
result from its use.

6505-110602-4

FIGURE 3. TYPICAL WALL SWITCH OCCUPANCY SENSOR APPLICATION

R1 = 36k

R7 = 1k

R2 = 2.7M

R8 = 910k

R3 = 36k

R9 = 7.5k

R4 = 2.7M

R9 = 3.6k

R5 = 36k

R10 = 1.0M

(variable)

R6 = 240

,1/2W

R11= 51k

R6 = 1k

,1W

R12 = 10k

All Resistors 1/4W, all Capacitors 10V unless otherwise
specified. PIR = HEIMANN LHi 958 or 878 (Typical)

C1 = 33µF

C9 = 33µF

C2 = 0.01µF

C10 = 0.1µF

C3 = 33µF

C11 = 0.033µF

C4 = 0.01µF

D1 = 1N4004

C5 = 0.1µF

Z1 = 24V, 1/2W

C6 = 1.5µF, 250V

T1 = Q4008L4 (Typical)

C6 = 1.0µF, 400V

T1 = Q5004L4 (Typical)

C7 = 1000µF

U1 = LM78L05 or equivalent

C8 = 0.1µF, 250V

(5V Regulator)

C8 = 0.1µF, 400V

Q1 = MPS8099

= Component change for 220VAC

NOTES: 1. The R8, R9, C8 network provides a 2.7V Peak-to-Peak AC signal input to Pin 5.

2. The C7, D1, Z1, C6, R6 components generate the DC Supply Voltage for the LS6505.
3. The R1, C1, R2, C2, R3, C3, R4, C4, R5, C5 components and the two on-chip Differential Amplifiers set a
nominal gain of 5,500 with bandpass filtering of 0.13Hz to 6Hz.

When operated in Mode B or Mode
C, the wall switch occupancy sensor
shown in Figure 3 can easily be
adapted to operate with a remote
switch by adding an R-C network to
the occupancy sensor module. R
limits the current from the remote
module into Pin 11 of the LS6505
and C suppresses noise.

AC Hot

Remote Control

S = SPST (Mom-Off)

To Load

To P

Vss

t o L S 6 5 0 5 - 1 1

from MT2

Remote Switch Module

Occupancy Sensor Module

R = 510k

, 1 / 4 W

C = 0 . 0 1 µ F , 1 0 V

AC Hot

FIGURE 4. ADAPTING WALL SWITCH FOR 3-WAY OPERATION

AMP 1
OUT

AMP 1

(-)IN

AMP 2
(-)IN

AMP 1

(+)IN

AMP 2
OUT

TIMER

C O N T R O L

DEAD TIME

SEL

O P E R A T I O N

SEL

TRIAC
OUT

P U L S E

MODE

SEL

LED

OUT

AC MAINS

LOAD

MT2

MT1

C11

PIR
S E N S O R

R10

R11

L S 6 5 0 5

SEE
NOTE

OFF

AUTO

S1 = SPDT (Mom - Off - Mom)

S1 (MODE B, MODE C)

S1 (MODE A)

S1 = SPDT (On - Off - On)

NOTE:
Open for Mode A
Vss for Mode B
V

for Mode C

SPDT (On - Off - On)

SPDT (On - On)

WARNING

MODE
S E L E C T

R12

C10

OUT

LED

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