HT7612_10 Datasheet, PDF (4/18 Pages) Holtek Semiconductor Inc – General Purpose PIR Controller

HT7612
Functional Description
The following gives a description of the functional pins
on the device.
TEST
The TEST pin is an output which is used to test the 32
KHz system frequency. Note that the pin is a shared
TEST/SC pin. The TEST output pin can be used within 1
second after power-on.
SC
The SC pin is an output pin which is used to for LVD and
CDS detection. Note the pin is a shared TEST/SC pin.
The SC pin can be used 1 second after power-on.
DT
The DT pin is a delay time oscillator input pin. It is con-
nected to an external RC to obtain the desired output
turn-on duration. Variable output turn-on durations can
be achieved by selecting various values of RC or using
a variable resistor. The DT structure is shown as Fig.1.
V REF
DT
_
+
C om p
_
S R ^{C LK}
FFI
+
C om p
O s c illa to r
Fig.1 DT Oscillator Structure
BUZ/BUZ
The BUZ & BUZ pins are both CMOS output structures.
They will output 4 beep sounds within 1second to indi-
cate that the warm-up time has completed. These differ-
ential output pins can be used to drive a piezo buzzer.
The BUZ/BUZ structure are shown in Fig.2.
RELAY
B U Z /L V D
B U Z /C D S
Fig.2 Buzzer Pin Drive Buzzer
The RELAY pin is a CMOS output structure which is nor-
mally low and active high. The high duration is con-
trolled by the delay time oscillator and the MODE pin.
The RELAY pin structure is shown in Fig.3.
V DD
LO A D
AC
R E L A Y /L E D
10kW
R E LA Y
8050
Fig.3 RELAY Pin Drive RELAY
TRIAC
TRIAC pin is a CMOS output structure which will output
a series of pulses when active. The pulse train synchro-
nised by the ZC (zero crossing) input. The active dura-
tion is controlled by the delay time oscillator and the
MODE pin. The TRIAC structure is shown in Fig.4.
LO A D
T R IA C
68W
0 .0 4 7 m F
10kW
AC
T R IA C
Fig.4 TRIAC Pin Drive TRIAC
Rev. 1.20
4
February 9, 2010