HT761X - General Purpose PIR Controller - Features, Applications, and Functional Description

Oct 12, 2026

HT761X is a CMOS LSI chip built for automatic PIR lamp control, supporting both 2-wire configurations for triac drive and 3-wire configurations for relay drive. The PIR sensor converts infrared power variations caused by human motion into a voltage signal, which is evaluated by on-chip analog and timing blocks before turning the lamp on for an adjustable duration. Three modes (ON/AUTO/OFF) are selectable via the MODE pin, with an override capability during AUTO and a timing scheme based on external RC connections. Detailed electrical characteristics, pin functions, trigger timing criteria, and selection table guidance support design-in.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages12

Reading Time30 min

AccessFree to download

Features

Applications

General Description

Selection Table

Pin Assignment

Pin Description

Absolute Maximum Ratings

Electrical Characteristics

Trigger Timing

Functional Description

HT761X General Purpose PIR Controller Features • Stand-by current: 100µA (Typ.) • Override function • On-chip regulator • Auto-reset if the ZC signal disappears over • Adjustable output duration 3 seconds • CDS input • Operating voltage: 5V~12V • 40 second warm-up • 16 pin DIP or SOP packaging • ON/AUTO/OFF selectable by MODE pin Applications • PIR light controllers • Motion detectors General Description • Alarm systems • Auto door bells The HT761X is a CMOS LSI chip designed for use in automatic PIR lamp control. It can operate with a 2-wire configuration for triac applications or with a 3-wire configuration for relay applications. The chip is equipped with operational amplifiers, a comparator, timer, a zero crossing detector, control circuit, a voltage regulator, a system oscillator, and an output timing oscillator. Its PIR sensor detects infrared power variations induced by the motion of a human body and transforms it to a voltage variation. If the PIR output voltage variation conforms to the criteria (refer to the functional description), the lamp is turned on with an adjustable duration. The HT761X offers three operating modes (ON, AUTO, OFF) which can be set through the MODE pin. While the chip is working in the AUTO mode the user can override it and switch to the TEST mode, or manual ON mode, or return to the AUTO mode by switching the power switch. The chip is enclosed in a 16 pin DIP/SOP. Selection Table | Part Number | ZC off/on for
override | Flash on
mode auto
change | Override ON
duration | Comparator
window | Effective
trigger width | | --- | --- | --- | --- | --- | --- | | HT7610 | 2 times | Flash | 8 hrs | ~~ ~~1~~1~~6(VDD-VEE) | >24ms | | HT7611 | 1 time | No flash | 8 hrs | ~~ ~~1~~1~~6(VDD-VEE) | >24ms | 1 24th Mar ’97 HT761X Pin Assignment Block Diagram 2 24th Mar ’97 HT761X Pin Description | Pin No. | | Pin Name | I/O | Internal
Connection | Description | | --- | --- | --- | --- | --- | --- | | A | B | | | | | | 1 | 1 | VSS | I | — | Negative power supply | | 2 | | RELAY | O | CMOS | RELAY drive output through an external NPN transistor, active high | | | 2 | TRIAC | O | CMOS | TRIAC drive output
The output is a pulse output when active. | | 3 | 3 | OSCD | I/O | PMOS IN
NMOS OUT | Output timing oscillator I/O
It is connected to an external RC to adjust output duration. | | 4 | 4 | OSCS | I/O | PMOS IN
NMOS OUT | System oscillator I/O
OSCS is connected to an external RC to set the system frequency. The system frequency ≅ 16KHz for normal application. | | 5 | 5 | ZC | I | CMOS | Input for AC zero crossing detection | | 6 | 6 | CDS | I | CMOS | CDS is connected to a CDS voltage divider for daytime/night auto-detection. Low input to this pin can disable the PIR input. CDS a schmitt trigger input with 5-second input debounce time. | | 7 | 7 | MODE | I | CMOS | Operating mode selection input:
VDD: Output is always ON
VSS: Output is always OFF
Open: Auto detection | | 8 | 8 | VDD | I | — | Positive power supply | | 9 | 9 | VEE | O | NMOS | Regulated voltage output
The output voltage is about –4V with respect to VDD. | | 10 | 10 | RSTB | I | Pull-High | Chip reset input, active low | | 11 | 11 | OP1P | I | PMOS | Noninverting input of OP1 | | 12 | 12 | OP1N | I | PMOS | Inverting input of OP1 | | 13 | 13 | OP1O | O | NMOS | Output of OP1 | | 14 | 14 | OP2P | I | PMOS | Noninverting input of OP2 | | 15 | 15 | OP2N | I | PMOS | Inverting input of OP2 | | 16 | 16 | OP2O | O | NMOS | Output of OP2 | 3 24th Mar ’97 HT761X Absolute Maximum Ratings Supply Voltage ...............................–0.3V to 13V Input Voltage................. VSS–0.3V to V DD+0.3V Storage Temperature .................–50°C to 125°C Operating Temperature...............–25°C to 75°C Zero Crossing Current.....................max. 300µA Electrical Characteristics | Symbol | Parameter | Test Condition | | Min. | Typ. | Max. |

FAQs

What configurations does the HT761X support for output control?

The HT761X can be used with a 2-wire configuration for triac applications or a 3-wire configuration for relay applications.

How does the HT761X decide to turn the lamp on in AUTO mode?

The PIR sensor detects infrared power variations from human motion, converts them to a voltage variation, and the chip turns the lamp on when the PIR output meets the defined criteria described in the functional description and trigger timing notes.

How can output duration and system timing be adjusted?

Output duration is set by an external RC connected to the OSCD pin, and the system oscillator is set by an external RC connected to the OSCS pin.

Oct 12, 2026

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