Circuit Note

CN-0537

Circuits from the Lab® reference designs are engineered and tested

forquickandeasysystemintegrationtohelpsolve today’sanalog,

mixed-signal, and RF design challenges. For more information

and/orsupport,visitwww.analog.com/CN0537.

Devices Connected/Referenced

ADPD188BI

Integrated Optical Module for

Smoke Detection

ADP151

Ultralow Noise, 200 mA,

CMOS Linear Regulator

LT8410

Ultralow Power Boost

Converter with Output

Disconnect

Multistandard Verified Smoke Detector Solution

Rev. A

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EVALUATION AND DESIGN SUPPORT

Circuit Evaluation Boards

CN-0537 Reference Design Board (EVAL-CN0537-ARDZ)

ADICUP3029 Arduino Form Factor Development Board

(EVAL-ADICUP3029)

Design and Integration Files

Schematics, Layout Files, Bill of Materials

CIRCUIT FUNCTION AND BENEFITS

Since the 1970s, smoke detectors have become commonplace

in commercial and residential buildings. Two basic types of

detectors exist today, the ionization type that uses radioactive

matter to ionize the air and checks for an electrical imbalance,

and the photoelectric type that uses a light source aimed at an

angle away from a photodetector and checks for photodetector

current caused by the light reflecting from airborne particles

to the photodiode. Although a combination solution of both

types is recommended, the photoelectric smoke detector is more

popular due to its improved reliability in detecting common

house fires and faster response times to smoldering fires.

Unfortunately, smoke detector technology and regulations

have also remained virtually the same since the 1970s despite

the advances in electronics and common household materials

through the decades. New revisions in standards, such as

ANSI/UL 217 and ANSI/UL 268, published by Underwriters

Laboratory (UL), or the NFPA®

72 National Fire Alarm Code,

published by the National Fire Protection Agency (NFPA), aim

to address this gap by placing more complex requirements on

modern smoke detector designs. Other worldwide standards,

such as EN 14604, EN 54, and ISO 7240 will likely add similar

tests to address this and other concerns in the future, making

it more important to have more advanced sensing capabilities.

The goal of these updated standards is to increase safety and

decrease the number of fire related deaths by reducing the

number of false alarms that are generated from everyday

activity. For example, in addition to the traditional fire and

smoke sensitivity tests, the 8th edition of UL 217 and the 7th

edition of UL 268 now requires that smoke detectors do not

produce a false alarm during nuisance events, like cooking.

Therefore, modern smoke detectors must be able to

distinguish between a cooking nuisance event and a fire

event. Traditionally, this goal required a complicated solution

with multiple sensor technologies and a level of artificial

intelligence. However, the use of the ADPD188BI makes this

solution significantly more simple to implement.

The circuit shown in Figure 1 is a tested and verified smoke

detector reference design with an available algorithm and a

data set based on the ADPD188BI optical module. For easy

and rapid development, the design is made compatible with

the Arduino form factor controller platforms. Software and

embedded algorithms combined with the hardware can be

used to evaluate smoke and fire tests specified in 8th edition

of the UL 217 and the 7th edition of the UL 268 standards.

Verified algorithms are available for direct use to help deploy

the smoke detection solution faster, and additional data can

also be collected and added into the algorithm to adapt it for

other standards.