HT7611 查看數據表（PDF） - Holtek Semiconductor

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HT7611

General Purpose PIR Controller

Holtek Semiconductor 

• Override control

When the chip is working in the AUTO mode

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

valid PIR trigger signal and the output active

duration is controlled by the OSCD oscillating

period. The lamp can be switched always to

“ON” from the AUTO mode by either switch-

ing 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 sec-

onds by mask option). The term "override"

refers to the change of operating mode by

switching the power switch. The chip can be

toggled from ON to AUTO by an override op-

eration. If the chip is overridden to ON and

HT761X

there is no further override operation, it will

return to AUTO automatically after an inter-

nal preset ON time duration has elapsed. This

override ON time duration 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 decide the

output flash times (3 times) when changing

the operating mode. It will flash 3 times at a

1Hz rate each time the chip changes from the

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.

Fig.3 ZC override timing

RSTB

RSTB 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 RSTB pin is an open circuit (without

CRST), the initial time is the default (40 secs).

Fig.4 RSTB application example

Power on initial

The PIR signal amplifier requires a warm up

period after power-on. The input should be dis-

abled during this period.

In the AUTO mode within the first 10 seconds

of power-on initialization, the chip allows over-

ride control to enter the test mode. After 40

seconds of the initial time the chip allows over-

ride control between ON and AUTO. It will

remain in the warm up period if the total initial

time has not elapsed after returning to AUTO.

In case that the ZC signal disappears 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 RSTB pin as shown in Fig.4.

8

24th Mar ’97

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