BL59A65
Shanghai Belling Co., Ltd.
Photo Smoke Detector Control IC with
hush
BL59A65
DATASHEET
Introduction:
The BL59A65 is a low-current BiCMOS circuit providing all of the features
for a photoelectric type smoke detector. BL59A65 can be used in conjunction
with an infrared photoelectric chamber to sense scattered light from smoke
particles. Special features are incorporated in the design to facilitate calibration
and testing of the finished detector.
Features:
6 V to 12 V Operating Voltage Range
Supply Voltage current：less than 10uA
Internal Timer & Control for Reduced Sensitivity
Operating Temperature Range：－25½75℃
Power-ON Reset
ESD and Latch-up Protection
Piezoelectric Horn Driver
Interconnect Up to 50 Detectors
Continuous Modulated Tone Output For a Local or Remote Alarm
Condition
Package Type: DIP16; SOP16
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BL59A65
Pin Configuration:
Fig.1
Pin Configuration
MAXIMUM RATINGS (Voltage
referenced to Vss)
Symbol
ＶDD
ＶIN
IIN
T
A
Ｔstg
ＴL
Pin
No.
1 ,2
C1 , C2
Pin symbol
Parameter
Supply Voltage
Input Voltage
Input Current
Operating Temperature
Storage Temperature
Welding Temperature
Input/O
utput
External capacitor
connected to the pins
Range
-0.5½＋15
-0.3½ＶDD＋0.3
10
-25
½
+75
-55
½
+125
260
Function Description
Unit
V
V
mA
℃
℃
℃
PIN FUNCTIONAL DESCRIPTION
A capacitor connected to the pins determines the gain
of the photo amplifier.
This pin connects the cathode of the photo diode. The
photo diode is operated at zero bias.
The pin is the Regulated voltage Output. The value is
Vdd-5V.
Power supply
This pin is a output, which provides a pulsed base
current for the external npn transistor, which drives the
IR emitter.
3
DETECT
Input
Input to the photo
amplifier
4
STROBE
Output
Regulated voltage
Output
5 ,14
6
Vdd , V
SS
IRED
Output
Power/Gnd
Signal output
7
I/O
A connection at this pin allows multiple smoke
detectors (less than 50) to be interconnected.
8 ,9
BRASS,
SILVER
Output
Piezoelectric
Transducer Output
These TWO pins are used in conjunction with a
piezoelectric transducer.
The pin is used in conjunction with a piezoelectric
transducer feedback electrode.
This open-drain NMOS output is used to directly drive a
10
FEEDBACK
Inuput
Piezoelectric
Transducer Input
11
LED
Output
Signal output
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BL59A65
visible LED. The LED also indicates detector status as
follows (with component values as in the typical
application, all times nominal)
12
OSC
Input
OSC Input
The pin connects with external capacitor and resistor,
sets the internal clock low time.
13
R1
External capacitor
and resistor
connected to the pins
15
LS SET
Intput
Low sensitive set
The pin connects with external capacitor and resistor,
sets the internal clock high time, which is also IRED
pulse width.
This input pin serves two purposes in normal operation:
serves as an enable for the internal 10-minutes
(nominal) timer and also as the reference (set by
external resistor divider between VDD and STROBE)
for the smoke comparator during the timer mode. This
allows the detector to have a different sensitivity set
point during the timer mode. If the timer mode is not
used, this pin can be left open or connected to Vss,
which disables this mode.
16
TEST
Input
Test Input
This pin has an internal pull-down device and is used to
manually invoke Test Mode and Timer Mode. High
logic level on this pin initiates Push-to-Test Mode (Av =
1 + (C1/10) where C1 is in pF.). When push-button is
released, the input returns to Vss due to the pull down.
This high-to-low transition on the pin also resets and
starts the 10 minutes hush timer (Timer Mode).
FUNCTIONAL BLOCK DIAGRAM
Fig.2
Functional Block Diagram
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BL59A65
Circuit Characteristic
The gain is determined by external capacitor C1 and C2. A capacitor
connected to C2 determines the gain of the photo amplifier during standby. A
typical value for this low-gain mode is 4700 pF but should be selected based on
a specific photo chamber and the desired level of sensitivity to smoke.
AV= 1+(C2/10) where C2 is in pF. This gain increases by a nominal 10% after a
local alarm is detected (three consecutive detections).
I/O pin allows multiple smoke detectors to be interconnected. If a local smoke
condition occurs, this pin is driven high. As an input, this pin is sampled
nominally every 1.35 seconds during standby. Any local alarm condition
causes I/O to be ignored as an input. An internal nmos device acts as a charge
dump to aid in applications involving a large (distributed) capacitance. The
charge dump is activated at the end of local or test mode.
LED pin is an output pin, which is used to directly drive a visible LED. The load
for the low-battery test is applied to this output. The low-battery test does not
occur coincident with any other test or alarm signal. The LED also indicates
detector status as follows (with component values as in the typical application,
all times nominal):
Standby - Pulses every 43 seconds.
Local Smoke - Pulses every 0.67 second.
Remote Alarm - No pulses.
Test Mode - Pulses every 0.67 second.
Timer Mode - Pulses every 10 seconds
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BL59A65
Timing Diagram
Standby Timing Diagram
Local Alarm Timing Diagram
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Microchip MCU
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