HT7612B 查看數據表（PDF） - Holtek Semiconductor

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HT7612B

General Purpose PIR Controller

Holtek Semiconductor 

HT7612/HT7612B

CDS

The CDS pin is connected to an internal comparator input.

It is used to allow the device to distinguish between day

and night conditions. When the CDS input voltage is lower

than VL, the PIR amplifier circuit will be disabled and the

TRIAC and RELAY output pins will be inactive. When the

input voltage of the CDS is higher than VL, the outputs are

both active. The debounce time for the CDS pin for switch-

ing the outputs from an inactive to an active state is about

15~20 seconds for the HT7612 and less than 3 seconds

for the HT7612B. Connect this pin to VDD when this func-

tion is not used. The CDS timing is shown in Fig.7

CDS

Low

High

Status

Day Time

Night

Output

Disabled

Enabled

CDS

T R IA C &

R E LA Y

A c tiv e

In a c tiv e

A c tiv

Fig.7 CDS Timing

In Fig.8, RCDS and RY can be adjusted to obtain the de-

sired daytime detection level.

V REF

B U Z /C D S

VL

T E S T /S C

RY

R CDS

Fig.8 CDS Application Example

LED

The LED pin is a CMOS output pin which is used as a

valid trigger indicator. When the TRIAC/RELAY is acti-

vated, this pin will be active until the TRIAC/RELAY has

is switched OFF. The LED pin structure is shown in

Fig.9.

R E L A Y /L E D

1kW

T r ig g e r

In d ic a to r

Fig. 9 LED Pin Drive LED

LVD

LVD is a low voltage detector. When the detected volt-

age is lower than 1.1V, the LED flicker and the buzzer

will emit a tone.

In Fig10, assume RX, RLVD can be adjusted to obtain the

desired voltage detection level.

V DD

RX

B U Z /L V D

1 .1 V

R LV D

T E S T /S C

Fig.10 LVD Application Example

VREF

D

S

G

PIR

Sensor

Comparator

Input

OP1

Regulator

VM

OP2

VREF

VH

Comp1

VL Comp2

VH

VL

PIR Amplifier

VREF

VH

Output

VM

VL

Rev. 1.50

6

February 21, 2011

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