HT761X
CDS
LOW
HIGH
Status
Day Time
Night
PIR
OSCD
Disabled
OSCD is an output timing 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.
Enabled
C
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MODE
1
TD= ´ 21504
MODE is a tristate input pin used to select the operating
mode.
f
C
D
MODE Operating
Description
Status Mode
Output Timing Oscillator
Output is always ON:
RELAY outputs high for relay driving.
VDD
VSS
ON
TRIAC pulse train output is syn-
chronized by ZC for triac driving.
RELAY (TRIAC)
RELAY is an output pin set as a RELAY driving (active
high) output for the HT761xA, or as a TRIAC driving (ac-
tive low) output for the HT761xB.
Output is always OFF:
OFF
RELAY outputs low for relay driving.
TRIAC outputs high for triac driving.
The output active duration is controlled by the OSCD os-
cillating period.
Outputs remain in the off state until
activated by a valid PIR input trigger
HT761xA
HT761xB
Open
AUTO signal. When working in the AUTO
mode, the chip allows override con-
trol by switching the ZC signal.
OUTPUT
RELAY
TRIAC
CDS
CDS is a CMOS Schmitt Trigger input structure. It is
used to distinguish between day time and night time.
When the input voltage of CDS is high the PIR input is
enabled. On the other hand, when CDS is low the PIR
input is disabled. The input disable to enable debounce
time is 5 seconds. Connect this pin to VDD when this
function is not used. The CDS input is ignored when the
output is active.
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Rev. 1.30
4
October 12, 2009
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
