MOS (PTY) LTD.
Microsystems On Silicon
Member of ELMOS Semiconductor AG
M2000C
PIR Light Controller
for 3-Wire Applications
www.mos.co.za
Page 3 of 5
Rev. 1.0
Detailed Description___________________________________________
Input A mplifier
Band P ass
F ilter
Driv er
Mains Rectifier
Volta ge
Parameters
Oscilator
Reg ulato r
TRI A C D riv e r
Controller
Relay D riv e r
AD C
A/D Conv erter
BRI G H T
FA D E
ON -TI M E
SEN S
RELA Y
TRI A C
ACIN
PI RIN
VD D
V DDA
TC O M P
Mains Rectifier
The M2000C contains an on chip half wave rectifier.
The ACIN input is connected to the mains voltage
through an external voltage dropper resistor.
Voltage Regulator
A shunt regulator between VDD and VSS limits the supply
voltage to 5V. An external capacitor has to be
connected between VDD and VSS.
Oscillator
The IC contains an on chip oscillator. The frequency is
set to about 52 kHz for 50Hz systems and 64kHz for
60Hz systems by selecting the correct resistor between
CLOCK and VDD. All timing signals and cutoff
frequencies of the digital filters are derived from this
frequency.
Input amplifier and A/D Converter
The PIRIN input has an internal pull-down resistor and
DC decoupling circuitry. The signal voltage on the PIR
input is converted to a 14 bit digital value.
Band-Pass Filter
A 2
nd
order digital Butterworth band-pass filter
eliminates unwanted frequency components above and
below the band of interest (0.4Hz .. 7Hz).
Threshold Comparator
The output signal from the band pass filter is digitally
rectified and its peak value compared against a
threshold value calculated from the voltages on the
SENS and TCOMP inputs. Whenever the PIR signal
exceeds the threshold, the load is switched on.
Parameter Settings
The M2000C provides for five inputs, which are used to
define the operational parameters. The voltage applied
on these inputs are converted to 4 (3) bit digital values.
A value of 16 (8) corresponds to a voltage of >VDD/4, a
value of 0 to VDD/4/16 (8).
SENS: Sets the sensitivity threshold required to
generate a trigger condition. Eight different threshold
values are possible. Refer to table 3. The threshold
value internally recalculated with the temperature
compensation factor.
BRIGHT: Sets the maximum brightness of the light. The
brightness levels are divided into 15 equal steps. One
steps corresponds to 90*(1- 1/16) degrees phase angle.
FADE: Sets the time it takes to switch the light on or off
(soft dimming). Refer to table 3.
ON-TIME: Sets the time the light remains on. Refer to
table 3.
Pin
voltage/
VDD
On time (s)
Fade time
(s)
SENS
threshold
7/32
1280
3.7
128
6/32
640
3.3
64
5/32
320
2.8
32
4/32
160
2.1
16
3/32
80
1.2
8
2/32
40
0.9
4
1/32
20
0.3
2
0/32
10
0
1
Table 3: On-time and Fade-time
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