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HALL-EFFECT PICKUP IGNITION CONTROLLER
L482
HALL–EFFECT PICKUP IGNITION CONTROLLER
. DIRECT DRIVING OF THE EXTERNAL PO-
WER DARLINGTON
. CONTINUOUS COIL CURRENT PROTECTION
. CONDUCTION AND DESATURATION TIME
OUTPUT SIGNALS
. PERMANENT CONDUCTION PROTECTION
. OVERVOLTAGE PROTECTION FOR EXTER-
DIP16
RESET OUTPUT SIGNAL
. LOAD DUMP PROTECTION
NAL DARLINGTON
DESCRIPTION
The L482 is an integrated circuit designed for use
with an NPN darlington in breakerless ignition sy-
stems with hall-effect pickup sensors and high ener-
gy ignition coils.
It controls the energy stored in the ignition coil and
the desaturation time of the external darlington to
limit the power dissipation.
SO16
ORDERING NUMBERS : L482 (DIP16)
L482D1 (SO16)
The L482 is also particularly suitable for use as igni-
tion control and driving stage in more sophisticated
car electronic systems which employ microproces-
sor circuits.
PIN CONNECTIONS (top views)
DIP16
SO16
November 1991
1/11
. COIL CURRENT CHARGING ANGLE (DWELL)
. COIL CURRENT PEAK VALUE LIMITATION
CONTROL
311043320.002.png
L482
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
Unit
V R
Reverse Battery Voltage
– 14
V
V D
Dump Voltage
100
V
P to t
Power Dissipation at T amb =90
°
C
SO16
DIP
1.2
0.65
W
W
T j ,T stg
Junction and Storage Temperature Range
– 55 to 150
°
C
BLOCK DIAGRAM
THERMAL DATA
Symbol
Parameter
Value
Unit
R th j-amb
Thermal Resistance Junction-ambient ( DIP16 )
Max
90
°
C/W
R th j-al
Thermal Resistance Junction-alumina ( SO16 )
Max
50
°
C/W
(*) Thermal resistance junction-aluminia with the device soldered on the middle of an aluminia supporting substrate measuring 15 x 20mm ;
0.65mm thickness with infinite heatsink.
2/11
311043320.003.png
L482
PIN FUNCTIONS (refer to fig. 3 for DIP16 package)
N
°
Name
Function
1
CONDUCTION TIME
SIGNAL
A low level on this output signal indicates when the external darlington is in
the ON condition i.e. when the current flows through the coil (ton in fig.1)
2
HALL-EFFECT INPUT
Hall-effect Pickup Input. A high level on this pin enables the current driving
into the coil. The effective coil charge will be a function of the dwell control
logic. A High to Low transition from the Hall-effect pickup is the signal for
ignition actuation. The input signal, supplied by the open collector output
stage of the Hall-effect sensor, has a duty cycle typically about 70%.
3
DWELL CONTROL
The average voltage on the capacitor C 2 connected between this pin and
ground depends on the motor speed and the voltage supply. The
comparison between V C2 and V C5 voltages determines the timing for the
dwell control. The recommended value is 100nF using a 100K
W
resistor at
pin 7. For the optimized operation of the device, C2 = C5.
4
DWELL CONTROL TIMER The capacitor C5 connected between this pin and ground is charged when
the Hall-effect output is high and is discharged at the High to Low transition
of the Hall-effect signal. The recommended value is 100nF using a 100K
W
resistor at pin 7.
5
HALL SENSOR SUPPLY This pin can be used to project the Hall-effect pickup against the voltage
transients, The resistor R a limits the current into the internal zener.
6
DESATURATION TIME
SIGNAL
Open Collector Output Signal. This output is high when the external
darlington is in desaturation condition (current limitation), see t d pulse in fig.
1.
7
REFERENCE VOLTAGE A resistor R11 connected between this pin and ground sets the internal
current used to drive the external capacitors of the dwell control (C 2 and
C 5 ) and permanent conduction protection (C 1 ). The recommended value is
100K
W
.
8
PERMANENT CONDUCT.
PROTECTION TIMER
A capacitor C1 connected between this pin and ground determines the
intervention delay of the permanent conduction protection, t pc of the figure 2.
With a 1
m
F capacitor and 100K
W
resistor R 11 at pin 7 the typical delay is 1s.
9
PERMANENT CONDUCT.
RESET OUTPUT
(no available in
Micropackage) (*)
A low pulse on this output detects the intervention of the permanent
conduction protection, as shown in figure 2. Typically the duration of the
time t r is more than 100
m
s.
10
CURRENT SENSING
INPUT (*)
Connection for Coil Current Limitation. The current is measured on the
sense resistor R S and divided on R 1 /R 2 . The current limitation value is
given by :
I SENS
=
V SENS
R1
+
R2
R S
V
R2
11
DUMP PROTECTION
(*)
The device is protected against the load dump. In load dump condition an
internal circuit, based on a zener diode and a darlington transistor,
switches off the external darlington and short circuits the supply.
By means of the external divider R8/R9 the protection threshold can be
changed and is given as first approximation by:
V Dth
=
8.5
V U
R 9
M
<
5
V
10 - 4
V
R 8
R 9
(the resistor R9 value must be higher than 4K
W
).
12
POWER SUPPLY (*)
Supply Voltage Input. A 7V (typ) zener is present at the input. The external
resistor R 7 limits the current through the Zener for high supply voltages.
3/11
R 8 +
+
311043320.004.png
L482
PIN FUNCTIONS (continued)
N
°
Name
Function
13
GROUND
This pin must be connected to ground.
14
DRIVER COLLECTOR
The collector current for the internal driver which drives the external
darlington is supplied through this pin. The external resistor R 10 limits the
dissipation in the IC. The value of the resistor depends is a function of the
darlington used and on the limiting current in the coil.
15
OVERVOLTAGE
LIMITATION
The external is protected against overvoltage by means of an internal
zener available at this pin. The external divider R 5 /R 6 defines the limitation
value, given as first approximation by:
V ovp
= T
U
30
R 5
+
5
V
10 - 3
<
V
R 6
+
30
16
DRIVING STAGE
OUTPUT
Current Driver for the External Darlington. To ensure stability and precision
of Tdesat C 3 and R 3 must be used. Recommended value for R3 is 2K
W
in
order not to change the open loop gain of the system.
R C may be added to C 3 to obtain greater flexibility in various application
situations.
C 3 and RC values ranges are 1 to 100nF and 5 to 30K
W
depending on the
external darlington type.
(*) These pins refer only to the DIP package type.
For the SO 16 version the permanent conduction reset output signal is not available and the pin 9 becomes the current sensing input. Pin 10
replaces the pin 11 function, pin 11 becomes the power supply input and pin 12 is used as the signal ground.
ELECTRICAL CHARACTERISTICS (V S =14V, –40 ° C 3 T j
3 125 ° C referred to application circuit of
figure 3 regarding DIP-16 package version)
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V S
Operating Supply Voltage
6
28
V
I S
Supply Current
V 12 = 4.5V
25
mA
V Z
Zener Voltage (pin 12)
I Z = 80mA
6.5
8.8
V
V I
Sensor Input (pin 2)
LOW Voltage
HIGH
0.5
V
V
2.5
I I
Sensor Input Current (pin 2)
V I = LOW
V S = 6 to 16V
–12
–1
mA
V Hz
Hall-cell Supply Zener Voltage
(pin5)
I Hz = 10mA
19
22
25
V
I HZ
Hall-cell Supply Zener Current
(pin5)
t = 10ms
T AMB =25
100
mA
°
C
V CE sat
(V 14 –V 16 )
Series Darlington Driver Sat.
Voltage
I o = 70mA
I o = 150mA
0.4
0.6
1.0
V
V
V SENS
Current Limit. Sensing Voltage
(pin10)
V S = 6 to 16V
200
400
mV
I 3D
I 3C
I 3C /I 3D
C2 Discharge Current
C2 Charge Current
V S = 6 to 16V
(*) Note 1
0.2
5
6
3.4
20
35
m
A
m
A
V OVZ
External Darlington Overvoltage
Protection Zener Voltage
I OVZ = 5mA to 15mA
T AMB =25
25
30
35
V
°
C
V 7
Reference Voltage
2.5
3.5
V
t d
Desaturation Time
f = 40Hz V S = 14V
0.6
1.2
1.57
ms
4/11
311043320.005.png
L482
ELECTRICAL CHARACTERISTICS (Continued)
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
t PC
Permanent Conduction
Protection Time (pin 8) (see fig.
2)
V I =H
C I =1
1
3
5
s
m
F
V 1
Charging Angle Output Voltage
LOW
I SINK =0
I SINK = 1mA
I SOURCE = 1.5mA
I SOURCE = 2.5mA
0.5
1.2
V
V
V
V
HIGH
3
5
V 6
Desat. Time Output Low
Voltage
I 6 (sink) = 0.5mA
0.7
V
I 6L
Desat. Time Leakage Current
(pin6)
V 6 = 5V
10.5
m
A
I 9L
Permanent Conduction Reset
Leakage Current (pin9)
V 9 = 5V
10.5
m
A
APPLICATION INFORMATION
Figure 1 : Main Waveforms.
5/11
311043320.001.png

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