K0900E70 Datasheet, PDF (178/224 Pages) Teccor Electronics – Thyristor Product Catalog

AN1007
Application Notes
Time Delay Relay Circuit
By combining a 555 timer IC with a triac, various time delays of
several seconds can be achieved for delayed activation of solid
state relays or switches. Figure AN1007.15 shows a solid state
timer delay relay using a sensitive gate triac and a 555 timer IC.
The 555 timer precisely controls time delay of operation using an
external resistor and capacitor, as illustrated by the resistor and
capacitor combination curves. (Figure AN1007.16)
10 K
0.1 µF
3
8
4
2
555
5
1
0.01 µF
1K
6
R
7
10 M
C
1 µF
LOAD
MT2
G ^MT1
120 V
60 Hz
-10 V
1N4740
3.5 K
250 V
1N4003
_
10 µF
+
Figure AN1007.15 555 timer circuit with 10 second delay
100
10
1.0
1 ^KΩ
10 ^KΩ
100 ^KΩ
1 ^MΩ
10 ^MΩ
0.1
0.01
0.001
10ms 100ms 1ms
10ms 100ms
1.0
10
100
td TIME DELAY (s)
Figure AN1007.16 Resistor (R) and capacitor (C) combination curves
IR Motion Control
An example of a more complex triac switch is an infrared (IR)
motion detector controller circuit. Some applications for this cir-
cuit are alarm systems, automatic lighting, and auto doorbells.
Figure AN1007.17 shows an easy- to-implement automatic light-
ing system using an infrared motion detector control circuit. A
commercially available LSI circuit HT761XB, from Holtek, inte-
grates most of the analog functions. This LSI chip, U2, contains
the op amps, comparators, zero crossing detection, oscillators,
and a triac output trigger. An external RC that is connected to the
OSCD pin determines the output trigger pulse width. (Holtek
Semiconductor Inc. is located at No.3, Creation Road II, Science-
Based Industrial Park, Hsinchu, Taiwan, R.O.C.) Device U1 pro-
vides the infrared sensing. Device R13 is a photo sensor that
serves to prevent inadvertent triggering under daylight or other
high light conditions.
Choosing the right triac depends on the load characteristics. For
example, an incandescent lamp operating at 110 V requires a
200 V, 8 A triac. This gives sufficient margin to allow for the high
current state during lamp burn out. U2 provides a minimum out-
put triac negative gate trigger current of 40 mA, thus operating in
QII & QIII. This meets the requirements of a 25 mA gate triac.
Teccor also offers alternistor triacs for inductive load conditions.
This circuit has three operating modes (ON, AUTO, OFF), which
can be set through the mode pin. While the LSI chip is working in
the auto mode, the user can override it and switch to the test
mode, or manual on mode, or return to the auto mode by switch-
ing the power switch. More information on this circuit, such as
mask options for the infrared trigger pulse and flash options, are
available in the Holtek HT761X General Purpose PIR Controller
specifications.
C7
3900pF
AC+
110
SW1
ON/OFF
OVERRIDE
LP1
Lamp
60 to
600
Watt
C8
0.1µF
D3
R9
1N4002 ^1M
R9
1M
C3
100pF
R7
1M
R8 569K
R2
2.4M
SW2
Mode
R6
1
VSS
2
TRIAC
3 _OSCD
U2
OP20 ¹⁶
15
OP2N
14
OP2P
1M
C5
0.02µF
C6
22µF
R5
22K
4 _OSCS
OP10 ¹³
5 _ZC
6 _CDS
7 _MODE
8 _VDD
12
OP1N
11
OP1P
10
RSTB
9
C12
22µF
R12
22K
VEE
R4
C2
1M
0.02µF
HT761XB
-16 DIP/SOP
C13
0.02µF
Q1
TRIAC
Q2008L4
R14
68W 2W
D5
1N4002
D4
1N4002
C10
0.33µF
350V
*R10
D2
1N4002
D1
12V
C11
330µF
R13
CDS
C4
100µF
R3
56K
3
2
G
S
D
1
U1
PIR
SD622
(Nippon
Ceramic)
C9
10µF
C1
100µF
AC
Figure AN1007.17 I R motion control circuit
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AN1007 - 6
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Thyristor Product Catalog