HAMAMATSU C3704-03, C3704-02, C3704 Datasheet

UV TRON® DRIVING CIRCUIT

C3704 SERIES

Compact, Lightweight, Low Current Consumption, Low Cost

Operates as High Sensitivity UV Sensor with UV TRON

Suitable for Flame Detectors and Fire Alarms

Hamamatsu C3704 series UV TRON driving circuits are low
current consuming, signal processing circuits for the UV TRON,
well known as a high sensitivity ultraviolet detecting tube. The
C3704 series can be operated as a UV sensor by connecting the
UV TRON and applying DC low voltage, as they have both a high­voltage power supply and a signal processing circuit on the same
printed circuit board.
Since background discharges of the UV TRON caused by natural
excitation lights (such as a cosmic ray, scattered sunlight, etc.)
can be cancelled in the signal processing circuit, the output
signals from the C3704 series can be used without errors.
When the high sensitivity sensor “UV TRON R2868” (sold
separately) is used, the flame from a cigarette lighter (flame
length: 25mm) can be detected even from a distance of more
than 5m.

APPLICATIONS

● Flame detectors for gas and oil lighters

● Fire alarms

● Combustion monitors for burners

● Electric spark detector

● UV photoelectric counter

SPECIFICATIONS

Dimensional outline..................................................... Figure 1

Weight ................................................................... Approx. 20g

Output signal ....... Open collector Output (50 V, 100 mA Max.)

10 ms width pulse output (Note : 1)

UV TRON supply voltage .......................... DC 350 V (Note : 2)

Quenching time ................................................. Approx. 50 ms

Operating temperature ......................................... -10 to +50°C

(with no condensation)

Suitable UV TRON ............... Low voltage operation UV TRON

(such as R2868)

C3704 C3704-02 C3704-03

Input Voltage

10 to 30 Vdc

5Vdc ± 5% 6 to 9 Vdc

Current consumption 3 mA Max. 300µA Max. 300µA Max.

Note 1: The output pulse width can be extended up to about 100s by adding a

capacitor to the circuit board.

Note 2: Since the output impedance of this power supply is extremely high, an

ordinary voltmeter cannot be used. Use a voltmeter that has an input
impedance of more than 10 GΩ.

Subject to local technical requirements and regulations, availability of products included in this promotional material may vary. Please consult with our sales office.

Information furnished by HAMAMATSU is believed to be reliable. However, no responsibility is assumed for possible inaccuracies or omissions.
Specifications are subjected to change without notice. No patent rights are granted to any of the circuits described herein. © 1997 Hamamatsu Photonics K. K.

TPT A0024EA

Figure 1: Dimensional Outline (Unit : mm)

-

+

123

9
7
5
3

K

A

3.54-

<Top View>

<Side View>

60

5

60

5

1.6

15

MAX.

UV TRON® DRIVING CIRCUIT C3704 SERIES

Figure 2: Schematic Diagram

HAMAMATSU PHOTONICS K.K., Electron Tube Center
314-5, Shimokanzo, Toyooka-village, Iwata-gun, Shizuoka-ken, 438-0193, Japan, Telephone: [phone], Fax: [phone], Telex: 4225-186HAMAHQ

U.S.A.:

Hamamatsu Corporation: 360 Foothill Road, Bridgewater, N.J. 08807-0910, U.S.A., Telephone: [phone], Fax: [phone]

Germany:

Hamamatsu Photonics Deutschland GmbH: Arzbergerstr. 10, D-82211 Herrsching am Ammersee, Germany, Telephone: [phone], Fax: [phone]

France:

Hamamatsu Photonics France S.A.R.L.: 8, Rue du Saule Trapu, Parc du Moulin de Massy, 91882 Massy Cedex, France, Telephone: [phone], Fax: [phone]

United Kingdom:

Hamamatsu Photonics UK Limited: Lough Point, 2 Gladbeck Way, Windmill Hill, Enfield, Middlesex EN2 7JA, United Kingdom, Telephone: [phone], Fax: [phone]

North Europe:

Hamamatsu Photonics Norden AB: Färögatan 7, S-164-40 Kista, Sweden, Telephone: [phone], Fax: [phone]

Italy:

Hamamatsu Photonics Italia S.R.L.: Via Della Moia, 1/E 20020 Arese, (Milano), Italy, Telephone: [phone], Fax: [phone]

(Note 3)

POWER SUPPLY INPUT AND SIGNAL OUTPUT POINT

– : GND
+ : POWER SUPPLY INPUT

1 : SIGNAL OUTPUT Q
2 : SIGNAL OUTPUT Q
3 : OPEN COLLECTOR OUTPUT

PRECAUTIONS FOR USE

● Since the operation impedance is extremely high, the UV TRON should be connected as close as possible to the circuit

board within 5 cm.

● Take care to avoid external noise since a C-MOS IC is used in the circuit. It is recommended that the whole PC board be put

in the shield box when it is used.

● To reduce current consumption, oscillating frequency is very low (approx. 20 Hz) in this DC-DC converter. Thus, the output

impedance of the high voltage power supply is extremely high. If the surrounding humidity is high, electrical leakage on the
PC board surface may lead to a drop in the supply voltage to the UV TRON. This voltage drop may result in lowered detec­tion performance, so a moistureproof material (silicone compound, etc.) should be applied at the connecting point of the
UV TRON, etc., if using the unit in a humid environment.

● A model equipped with a flame sensor (R2868) is also available.

Figure 3: Method of Connection

TPT C0004EA

Note 3: No load can be driven by an output from points “1” and “2” because these signals are

output from the only C-MOS IC directly. When a load such as a buzzer and a relay is
connected to this circuit, it should be connected to the point open collector output. The
transistor ratings of the open collector is 50V, 100mA. Be careful not to exceed the ratings.

Note 4: The output pulse width is set to 10ms at shipping. If the pulse width needs to be

extended, add a capacitor to this point. (When using an electrolytic condenser, make
sure the polarity is correct.)
e.g. CX = 1 µF: Pulse Width

1s, CX=10 µF : Pulse Width 10s

▲

▲

Cx: POINT FOR ADDING A CAPACITOR TO

EXTEND OUTPUT PULSE WIDTH (Note 4)

CONNECTING POINT OF UV TRON
A : Connecting Anode of UV TRON
K : Connecting Cathode of UV TRON

▲

JUMPER LEAD FOR SETTING
BACKGROUND CANCEL LEVEL

▲

This background cancel circuit outputs signal pulses
of 10ms width only when 3 to 9 pulses enter the
circuit with a time interval of 2 seconds or less from
the UV TRON. Cancel level can be set in 4 steps
(number of pulses: 3, 5, 7, 9) by this jumper lead.
Connect to “3” for general use. When using where
much natural excitation light is present, set the
cancel level at a higher step (5, 7, 9).

TPT1007E01
JUL.1997 CR
Created in Japan

UV TRON
(SOLD SEPARATELY)

K

A

CATHODEANODE

POWER SUPPLY

+

–
GND

CONSTANT *
VOLTAGE
CIRCUIT

HIGH VOLTAGE
DC-DC

CONVERTER

JUMPER LEAD FOR SETTING
BACKGROUND CANCEL LEVEL

* Not included in C3704-02.

OPEN COLLECTOR
OUTPUT (3)

Q (1)
Q (2)

10 ms
(Note 4)

GND

GND
5V

5V

Q

Q

OUTPUT SIGNAL
WAVEFORM

7

SIGNAL
PROCESSING
CIRCUIT

395

+350Vdc

Tr : 50

100mA

•

+5Vdc