HT761X 데이터 시트보기 (PDF) - Holtek Semiconductor

부품명

상세내역

일치하는 목록

HT761X

General Purpose PIR Controller

Holtek Semiconductor 

HT761X

ZC

ZC is a CMOS input structure. It receives AC line fre-

quency and generates zero crossing pulses to synchro-

nize the triac driver. By effective ZC signal switching

(switch OFF/ON 1 or 2 times within 3 seconds by mask

option), the chip provides the following additional func-

tions:

· Test mode control

Within 10 seconds after power-on, effective ZC

switching will force the chip to enter the test mode.

During the test mode, the outputs will be active for a

duration of 2 seconds each time a valid PIR trigger

signal is received. If a time interval exceeds 32 sec-

onds without a valid trigger input, the chip will auto-

matically enter the AUTO mode.

· Override control

When the chip is working in an AUTO mode

(MODE=open), the output is activated by a valid PIR

trigger signal and the output active duration is con-

trolled by an OSCD oscillating period. The lamp can

be switched always to ²ON² from the AUTO mode by

either switching the MODE pin to VDD or switching

the ZC signal by an OFF/ON operation of the power

switch (OFF/ON once or twice within 3 seconds by

mask option). The term ²override² refers to the

change of operating mode by switching the power

switch. The chip can be toggled from ON to AUTO by

an override operation. If the chip is overridden to ON

and there is no further override operation, it will auto-

matically return to AUTO after an internal preset ON

time duration has elapsed. This override ON time du-

ration can be set to 4 or 6 or 8 hours by mask option.

The default is 8 hours.

The chip provides a mask option to determine the out-

put flash times (3 times) when changing the operating

mode. It will flash 3 times at a 1Hz rate each time the

chip changes from an AUTO mode to another mode or

flash 3 times at a 2Hz rate when returning to the

AUTO mode. But if the AUTO mode is changed by

switching the MODE switch it will not flash.

RST

RST is used to reset the chip. It is internal pull-high and

active low.

The use of CRST can extend the power-on initial time. If

the RST pin is an open circuit (without CRST), the initial

time is the default (40 secs).

O p e r a tin g

M ode

AU TO

fla s h

ON

fla s h

AU TO

ZC

REST

V DD

VCC

100mF

RST

C RST

VEE

Fig.1 RST Application Example

Power-on Initial

The PIR signal amplifier requires a warm up period after

power-on. The input should be disabled during this pe-

riod.

In the AUTO mode within the first 10 seconds of

power-on initialization, the chip allows override control

to enter the test mode. After 40 seconds of the initial

time the chip allows override control between ON and

AUTO. It will remain in the warm up period if the total ini-

tial time has not elapsed after returning to AUTO.

In case that the ZC signal disappears for more than 3

seconds, the chip will restart the initialization operation.

However, the restart initial time is always 40 seconds

and cannot be extended by adding CRST to the RST pin

as shown in the Fig.1.

Mask Options

The HT761x offers mask options to select the output

flash (3 times) when changing the operating mode. The

chip will flash 3 times at a 1Hz rate each time it changes

from AUTO to another mode and flash 3 times at a 2Hz

rate when it returns to the AUTO mode. However the

chip will not flash if the mode is changed by switching

the MODE switch.

· 4, 6, or 8 hour options to return to AUTO from override

ON. The default is 8 hours.

· Options for effective override: Once or twice Off/On

operation of power switch within 3 seconds. The de-

fault is Off/On twice.

· Options for output flash to indicate effective override

operation. The default is to flash.

· Options for effective PIR trigger pulse width: >24ms,

>32ms or >48ms. The default is 24ms.

fla s h

ON

4 , 6 o r 8 h r b y m a s k o p tio n

fla s h

AU TO

ZC Override Timing

Rev. 1.30

5

October 12, 2009

Share Link: