HT7612 datasheet(6/18 Pages) HOLTEK

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HT7612

Rev. 1.20

February 9, 2010

CDS

The CDS pin is a CMOS Schmitt Trigger 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 CDS is higher than VL, the outputs

are both active. The debounce time for the CDS pin for

switching the outputs from an inactive to an active state

is about 15~20 seconds. Connect this pin to VDD when

this function is not used. The CDS timing is shown as

Fig.7

CDS

Status

Output

Low

Day Time

Disabled

High

Night

Enabled

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

sired day time detection level.

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.

LVD

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

age is lower than VH, the LED will be flicker and the

buzzer will emit such as a tone.

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

desired voltage detection level.

OP2

OP1

Regulator

Comp1

Comp2

VREF

PIR

Sensor

Output

Comparator

Input

VREF

PIR Amplifier

C D S

T R I A C &

R E L A Y

A c t i v e

I n a c t i v e

A c t i v

Fig.7 CDS Timing

B U Z / C D S

V R E F

V L

T E S T / S C

R C D S

R Y

Fig.8 CDS Application Example

1 k W

T r i g g e r

I n d i c a t o r

R E L A Y / L E D

Fig. 9 LED Pin Drive LED

B U Z / L V D

V D D

V H

T E S T / S C

R X

R L V D

Fig.10 LVD Application Example

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