STMicroelectronics L9686 Automotive direction indicator Datasheet

L9686
®
AUTOMOTIVE DIRECTION INDICATOR
RELAY DRIVER IN CAR DIRECTION
INDICATORS
FLASH FREQUENCY DOUBLES TO INDICATE LAMP FAILURE
DUMP PROTECTION ( ± 80 V)
REVERSE BATTERY PROTECTION
DESCRIPTION
The L9686 is a two frequency oscillator particularly suitable as relay driver for flashing light control in automotive applications. The circuit may be
also used for other warning lamps like "handbrake
on" etc. The lamp failure detection is given by
doubling the flash repetition frequency. The
L9686 is supplied in minidip 8-lead and SO8 plastic packages.
MINIDIP
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ORDERING NUMBERS:
L9686
L9686D
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BLOCK DIAGRAM
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SO8
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September 2003
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L9686
PIN CONNECTION (Top view)
DEVICE GND
1
8
STARTER
+VBATT
2
7
FAULT DET.
OUTPUT
3
6
N.C.
OSCILLATOR
4
5
OSCILLATOR
D95AT175
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ABSOLUTE MAXIMUM RATINGS
Symbol
VS
Parameter
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Transient Peak Supply Voltage (R3 > 220Ω):
Load Dump:
5ms < trise < 10ms
τf Fall Time Constant = 100ms
Rsource > 0.5Ω
Field Decay:
5ms < tfall < 10ms, Rsource > Ω
τr Rise Time Constant = 33ms
Low Energy Spike:
trise = 1µs, tfall = 2ms, Rsource > 10Ω
Junction and Storage Temperature Range
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Value
Unit
80
V
– 80
V
± 100
V
– 55 to 150
°C
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THERMAL DATA
Symbol
Rth j-amb
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Parameter
Thermal Resistance Junction-ambient
Max.
SO8
Minidip
Unit
180
100
°C/W
L9686
ELECTRICAL CHARACTERISTICS (– 20°C < Tamb <, 100°C, 8V < VS < 18V unless otherwise specified.)
Symbol
Parameter
Test Condition
Min.
Operating Voltage
Typ.
Max.
Unit
8
18
V
27
34
V
VS
V2 – V1
Clamping Voltage
see note 1
V2 – V3
Output Saturation Voltage
IRL = 250mA
1.7
V
see note 2
Fn = 1/KnRoCo
Osc. Frequency
3.6
1.74
KΩ
KN
Starter Resistance
Oscillator Constant KN (normal
Operation)
CT
Temperature Coefficient of Kn
See Note 3
R2
D.C.
–1.5 ⋅
10-3
Duty Cycle (normal operation)
KC
Oscillator Constant KC
(lamp failure detection)
DCLF
Duty Cicle (lamp failure
detection)
45
FC = 1KcRoCo
Osc. Frequency
Current Consumption Relay off
Ipin 1
Vth
Lamp Failure Threshold
(see note 4)
50
0.53
35
IQ
Notes : 1.
1.27
VS = 8V
VS = 13.5V
VS = 18V
R3 = 220Ω
VS = 13.5V
–20 < Tamb < 100°C
65
1/°C
55
%
0.74
40
45
2.2
2.7
3.3
3.9
4.3
4.7
mA
mA
mA
85
95
mV
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This voltage is the threshold used to protect the circuit against overvoltage : if V bat is > than this threshold, the relay will be on
and the voltage across the circuit will maintain constant increasing the current in the protective resistor R3.
This is the maximum value for operation. This value must be higher than 1 K Ohms in order to limit the current in pin 8 during
dumps. A recommended value for application should be 1,5 K Ohms.
The external leakage from the blinker unit to ground must be with an equivalent resistor higher than 5,6 K Ohms to avoid parasitic operation when the switch S1 is off.
This temperature coefficient is usefull to compensate the drift of the external timing network (R1, C1).
This threshold is calculated for a 20 m Ohm shunt. The threshold is dependant of Vbat as the bulb current.
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3.
4.
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FUNCTIONAL DESCRIPTION
The circuit is designed to drive the direction indicator flasher relay. The application circuit shows
the typical system configuration with the external
components. Its consists of a network (R1 C1) to
determine the oscillator frequency, shunt resistor
(RS) to detect defective bulbs and two current limiting resistors (R2/R3) to protect the IC against
load dump transients.
The lightbulbs L2, L3, L4, L5, are the turn signal indicators with the dashboard-light L6. The S1
switch position is sensed across resistor R2
and Rlamp by input 8. The flashing cycle is started
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by closing S1 : then, after a delay time td typically
equal to 1.5 ms, the relay is actuated and the pin
3 goes high switching on the corresponding
lamps L2, L3, (or L4, L5). These lamps will flash at
the oscillator frequency not depending on the battery voltage value (8 - 18 V). The flashing cycle
stops and the circuit is reset to the initial position
when the switch S1 is open.
The lamp failure detection function senses the
current through the shunt resistor RS. When one
of the lightbulbs is defective the voltage drop
across RS is reduced to a half and the failure is
indicated by doubling the flashing frequency.
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L9686
Figure 1: Application Circuit.
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L9686
mm
inch
OUTLINE AND
MECHANICAL DATA
DIM.
MIN.
A
TYP.
MAX.
MIN.
3.32
TYP.
MAX.
0.131
a1
0.51
0.020
B
1.15
1.65
0.045
0.065
b
0.356
0.55
0.014
0.022
b1
0.204
0.304
0.008
0.012
D
E
10.92
7.95
9.75
0.430
0.313
0.384
e
2.54
0.100
e3
7.62
0.300
e4
7.62
0.300
F
6.6
0.260
I
5.08
0.200
L
3.18
Z
3.81
0.125
1.52
0.150
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0.060
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L9686
mm
DIM.
MIN.
TYP.
A
inch
MAX.
MIN.
TYP.
a1
1.75
0.1
0.25
a2
MAX.
0.069
0.004
0.010
1.65
0.065
a3
0.65
0.85
0.026
0.033
b
0.35
0.48
0.014
0.019
b1
0.19
0.25
0.007
0.010
C
0.25
0.5
0.010
0.020
D (1)
4.8
5.0
0.189
0.197
E
5.8
6.2
0.228
0.244
c1
OUTLINE AND
MECHANICAL DATA
45° (typ.)
e
1.27
0.050
e3
3.81
0.150
F (1)
3.8
4.0
0.15
0.157
L
0.4
1.27
0.016
0.050
M
0.6
0.024
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8 ° (max.)
S
(1) D and F do not include mold flash or protrusions. Mold flash or
potrusions shall not exceed 0.15mm (.006inch).
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L9686
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Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is
granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are
subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products
are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.
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