UL
®
LSI/CSI
LSI Computer Systems, Inc. 1235 Walt Whitman Road, Melville, NY 11747
LS6505
(631) 271-0400 FAX (631) 271-0405
November 2002
A3800
PIR SENSOR INTERFACE
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.
6505-110602-1
PIN ASSIGNMENT - TOP VIEW
DIFF. AMP. 1 OUTPUT
DIFF. AMP. 2 INPUT (-)
DIFF. AMP. 2 OUTPUT
MODE SELECT INPUT
AC INPUT
V
SS
TRIAC OUTPUT
1
2
3
4
5
6
7
16
15
14
DIFF. AMP 1 INPUT (-)
DIFF. AMP 1 INPUT (+)
WARNING OUTPUT
TIMER CONTROL INPUT
DEAD TIME SELECT INPUT
OPERATION SELECT INPUT
PULSE MODE
SELECT INPUT
LED OUTPUT
LSI
LS6505
FIGURE 1
13
12
11
10
9
V
DD
8
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
DD
= 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
V
DD
Open
Vss
Mode A
On
Auto
Off
Mode B
(1)
Prior Condition
(2)
Mode C
(3)
Auto
(4)
(1)
Momentary application of V
DD
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.
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