L482D1 [STMICROELECTRONICS]
HALL.EFFECT PICKUP IGNITION CONTROLLER; HALL.EFFECT皮卡点火控制装置
| 型号： | L482D1 |
| 厂家： | 
ST |
| 描述： | HALL.EFFECT PICKUP IGNITION CONTROLLER |
| 文件： | 总11页 (文件大小：171K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
L482
HALL–EFFECT PICKUP IGNITION CONTROLLER
.
.
DIRECT DRIVING OF THE EXTERNAL PO-
WER DARLINGTON
COIL CURRENT CHARGING ANGLE (DWELL)
CONTROL
COIL CURRENT PEAK VALUE LIMITATION
CONTINUOUS COIL CURRENT PROTECTION
CONDUCTION AND DESATURATION TIME
OUTPUT SIGNALS
PERMANENT CONDUCTION PROTECTION
RESET OUTPUT SIGNAL
OVERVOLTAGE PROTECTION FOR EXTER-
NAL DARLINGTON
.
.
.
DIP16
.
.
.
LOAD DUMP PROTECTION
DESCRIPTION
SO16
The L482 is an integrated circuit designed for use
with an NPN darlington in breakerless ignition sy-
stems with hall-effect pickup sensorsandhigh ener-
gy ignition coils.
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.
It controls the energy stored in the ignition coil and
the desaturation time of the external darlington to
limit the power dissipation.
PIN CONNECTIONS (top views)
DIP16
SO16
1/11
November 1991
L482
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
– 14
100
Unit
V
VR
VD
Reverse Battery Voltage
Dump Voltage
V
Ptot
Power Dissipation at Tamb = 90°C
SO16
DIP
1.2
0.65
W
W
Tj, Tstg
Junction and Storage Temperature Range
– 55 to 150
°C
BLOCK DIAGRAM
THERMAL DATA
Symbol
Parameter
Value
90
Unit
°C/W
°C/W
Rth j-amb
Rth j-al
Thermal Resistance Junction-ambient (DIP16)
Thermal Resistance Junction-alumina (SO16)
Max
Max
50
(*) 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
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
3
4
HALL-EFFECT INPUT
DWELL CONTROL
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%.
The average voltage on the capacitor C2 connected between this pin and
ground depends on the motor speed and the voltage supply. The
comparison between VC2 and VC5 voltages determines the timing for the
dwell control. The recommended value is 100nF using a 100KΩ resistor at
pin 7. For the optimized operation of the device, C2 = C5.
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 100KΩ
resistor at pin 7.
5
6
HALL SENSOR SUPPLY
This pin can be used to project the Hall-effect pickup against the voltage
transients, The resistor Ra limits the current into the internal zener.
DESATURATION TIME
SIGNAL
Open Collector Output Signal. This output is high when the external
darlington is in desaturation condition (current limitation), see td 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 (C2 and
C5) and permanent conduction protection (C1). The recommended value is
100KΩ.
8
9
PERMANENT CONDUCT. A capacitor C1 connected between this pin and ground determines the
PROTECTION TIMER
intervention delay of the permanent conduction protection, tpc of the figure 2.
With a 1µF capacitor and 100KΩ resistor R11 at pin 7 the typical delay is 1s.
PERMANENT CONDUCT. A low pulse on this output detects the intervention of the permanent
RESET OUTPUT
conduction protection, as shown in figure 2. Typically the duration of the
(no available in
time tr is more than 100µs.
Micropackage) (*)
10
11
CURRENT SENSING
INPUT (*)
Connection for Coil Current Limitation. The current is measured on the
sense resistor RS and divided on R1/R2. The current limitation value is
given by :
R1 + R2
RS R2
I
SENS = VSENS
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:
R8 + R9
R9
VDth = 8.5
+ 5 10−4 R8
(the resistor R9 value must be higher than 4KΩ).
12
POWER SUPPLY (*)
Supply Voltage Input. A 7V (typ) zener is present at the input. The external
resistor R7 limits the current through the Zener for high supply voltages.
3/11
L482
PIN FUNCTIONS (continued)
N°
13
14
Name
GROUND
Function
This pin must be connected to ground.
DRIVER COLLECTOR
The collector current for the internal driver which drives the external
darlington is supplied through this pin. The external resistor R10 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
16
OVERVOLTAGE
LIMITATION
The external is protected against overvoltage by means of an internal
zener available at this pin. The external divider R5/R6 defines the limitation
value, given as first approximation by:
30
R5
Vovp
=
+ 5 10−3 R6 + 30
DRIVING STAGE
OUTPUT
Current Driver for the External Darlington. To ensure stability and precision
of Tdesat C3 and R3 must be used. Recommended value for R3 is 2KΩ in
order not to change the open loop gain of the system.
RC may be added to C3 to obtain greater flexibility in various application
situations.
C3 and RC values ranges are 1 to 100nF and 5 to 30KΩ 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 (VS = 14 V, – 40°C ≤ Tj ≤ 125°C referred to application circuit of
figure 3 regarding DIP-16 package version)
Symbol
Parameter
Operating Supply Voltage
Supply Current
Test Conditions
Min.
Typ.
Max.
28
Unit
V
VS
IS
6
V12 = 4.5V
25
mA
V
VZ
VI
Zener Voltage (pin 12)
IZ = 80mA
6.5
8.8
Sensor Input (pin 2)
LOW Voltage
HIGH
0.5
–1
25
V
V
2.5
II
VHz
Sensor Input Current (pin 2)
VI = LOW
VS = 6 to 16V
–12
mA
Hall-cell Supply Zener Voltage IHz = 10mA
(pin5)
19
22
V
IHZ
Hall-cell Supply Zener Current t = 10ms
100
mA
(pin5)
Series Darlington Driver Sat. Io = 70mA
Voltage Io = 150mA
TAMB = 25°C
VCE sat
(V14–V16
0.6
1.0
V
V
)
0.4
VSENS
Current Limit. Sensing Voltage VS = 6 to 16V
(pin10)
200
400
mV
I3D
I3C
I3C/I3D
C2 Discharge Current
C2 Charge Current
VS = 6 to 16V
(*) Note 1
0.2
5
6
3.4
20
35
µA
µA
VOVZ
External Darlington Overvoltage IOVZ = 5mA to 15mA
25
30
35
V
Protection Zener Voltage
TAMB = 25°C
V7
td
Reference Voltage
2.5
0.6
3.5
V
Desaturation Time
f = 40Hz VS = 14V
1.2
1.57
ms
4/11
L482
ELECTRICAL CHARACTERISTICS (Continued)
Symbol
Parameter
Permanent
Test Conditions
Min.
Typ.
Max.
Unit
tPC
Conduction VI = H
1
3
5
s
Protection Time (pin 8) (see fig. CI = 1µF
2)
V1
Charging Angle Output Voltage
LOW
ISINK = 0
ISINK = 1mA
ISOURCE = 1.5mA
ISOURCE = 2.5mA
0.5
1.2
V
V
V
V
HIGH
3
5
V6
I6L
I9L
Desat.
Voltage
Time
Output
Low I6 (sink) = 0.5mA
0.7
V
Desat. Time Leakage Current V6 = 5V
(pin6)
10.5
10.5
µA
µA
Permanent Conduction Reset
Leakage Current (pin9)
V9 = 5V
APPLICATION INFORMATION
Figure 1 : Main Waveforms.
5/11
L482
Figure 2 : Low Frequency Condition and Permanent Conduction Protection.
Figure 3 : Application circuit (DIP–16).
6/11
L482
Figure 4 : Application Circuit (SO–16).
CIRCUIT OPERATION
kept constant by desaturating the driver stage and
the externaldarlington.
The L482controltheconductiontime (dwell) andthe
peak value of the primary current in the coil overthe
full range of operating conditions.
The capacitor C5 starts charging on the positive
edge of the Hall-effect input signal with a constant
current I4C
.
The coil current is limited to a predetermined level
by means of a negative feedbackcircuit including a
current sensing resistor, a comparator, the driver
stage and the power switch.
The dwellangle,andconsequentlythe startingpoint
of thecoil current production,isdecidedby thecom-
parison betweenVC2 andVC5. A positive hysteresis
is added to the dwell comparator to avoid spurious
effectsand C5 is rapidly dischargedon the negative
edge of Hall-effects input signal.
The dwell control circuit maintains the output stage
in itsactive region during current limitation. The time
the outputstage is in the active region (desaturation
time) is sufficient to compensate for possible varia-
tions in the nergy stored due to the acceleration of
the motor ; moreover this time is limited to avoid ex-
cessive power dissipation.
In this way the average voltage on C2 increases if
the motor speed decreases and viceversa in order
td
to maintainconstant the ratio at any motor speed.
T
td is kept constant (and not d = cost) to control the
power dissipation and to have sufficient time to
avoid low energy sparks during acceleration.
CONTROL OF THE DWELL ANGLE (fig. 1 and 4)
The dwell angle control circuit calculates the con-
duction time D for the output transistor in relation to
the speed of rotation, to the supply voltage and to
the characteristic of the coil.
The charging time D – td dependson the coil and
the voltage supply.
DESATURATION TIMES IN STATIC CONDI-
TIONS.Instaticconditions,if C2 =C5 asrecommen-
ded and if the values of the application circuit of fig.
3, 4 are used.
On the negative edge of the Hall-effect input signal
the capacitorC2 beginsdischarging with a constant
current I3D. When the set peak value of the coil cur-
rent is reached, this capacitor charges with a con-
stant current I3C = 13.3 x I3D and the coil current is
td
1
=
T
1 + I3C/I3D
7/11
L482
DESATURATIONTIMES INLOWAND HIGH FRE-
QUENCYOPERATION.Due totheupperlimitofthe
voltage range of pin 3, if the componentsof fig. 3, 4
are used, below 10Hz (300RPM for a 4 cylinder en-
gine) the OFF time reaches its maximum value
(about50ms)andthen thecircuit graduallyloses the
control of the dwell angle because D = T – 50ms
DARLINGTON OVERVOLTAGE LIMITATION
The darlington is protected against overvoltage by
means of an external divider R5/R6 (pin 15) and an
internalzener. This zener drives the externaldarlin-
gton in order to limit the collector voltage.
REVERSE BATTERY PRTOTECTION. Due to the
presenceof externalimpedance at pin5, 10,11, 14,
15, L482 is protected against reverse battery volt-
age.
Over 200Hz (6000RPM for a 4 cylinder engine) the
available time for the conductionis less than3.5ms.
If the used coil is 6mH, 6A, the OFF time is reduced
to zero and the circuit loses the dwell angle control.
DUMP PROTECTION.
The load dump protection withstands up to 100V
with a decay time ≤ 300ms. The intervention thre-
shold for load dump is fixed by means of anexternal
divider connected to pin 11 (DIP-16 package ver-
sion) or to pin 10 using a Micropackage type.
TRANSIENT RESPONSE. The ignition system
must deliver constant energy even during the con-
dition of acceleration and deceleration of the motor
below 80Hz/s. These conditions can be simulated
by means of a signal generator with a linearly mo-
dulated frequency between 1Hz and 200Hz (this
correspondsto achangebetween30and6000RPM
for a 4 cylinders engine.
NEGATIVE SPIKE PROTECTION.If correct opera-
tion is requested also during short negative spikes,
the diode DS and capacitor Cs must be used.
CURRENT LIMIT. The current in the coil is monito-
red by measuring the Isense current flowing in the
sensingresistor Rs on theemitter oftheexternaldar-
lington. Isense is given by :
USE OF THE IC ELECTRONIC ADVANCE SY-
STEM
When the device is digitally controlled the control
unit transmits a suitable input signal to the power
module, receivingin turn information that allows the
control of the dwell and the on time of the final tran-
sistor.
I
sense = Icoil + I16
When the voltage drop across Rs reachesthe inter-
nal comparatorthresholdvalue the feedbackloop is
activatedand Isense kept constant (fig. 1) forcing the
external darlington in the active region. In this con-
dition :
For thisreasonL482providesthe following outputs:
Isense = Icoil
When aprecise peakcoil currentisrequiredR5 must
be trimmed or an auxiliary resistor divider (R1, R2)
added :
.
.
.
a time signal equal to the time in which the final
Darlington is in the active region i.e. when the coil
current is limited (Vds) as shown in figure 1. This
signal must be TTL compatible.
VSENS
R1
Icpeak (A)
=
(
+ 1)
RS
R2
PROTECTION CIRCUIT
a TTL compatible output from the timing circuit
(V in figure 2). This pulse, available only using
rs
PERMANENT CONDUCTION PROTECTION
the DIP-16 package version is present after the
protectionagainst cranking transients.
The battery voltage is applied to ignition module by
means of the ignition key. In these conditions, with
the motor stopped, it is necessary that there is no
permanent conductionin the ignition coil irrespecti-
ve of the polarity of the input signal.
a time signal equal to the time in which the final
Darlington,is in ”on” condition (Von) i.e. when the
current flows through the coil, see fig. 1.
The L482 incorporates a timing circuit to implement
this protection ; thedurationof the interventionisset
by means of a capacitor C1 at pin 8 = 1µF, and
R11 = 100kΩ, when the input signal is high for more
than 1 s, the coil current gradually decreases down
to zero to avoid spurious sparks (see fig. 2).
OTHER APPLICATION INFORMATION
If the supply voltage is disconnected - or the battery
wire is broken - while the current is flowing through
the coil, the externaldiode D1 keeps the coil current
from recirculating into the device : in this way both
device and darlington are protected.
This timing allows normal operation of the module
above 30RPM.
8/11
L482
DIP16 PACKAGE MECHANICAL DATA
mm
inch
TYP.
DIM.
MIN.
0.51
0.77
TYP.
MAX.
MIN.
0.020
0.030
MAX.
a1
B
b
1.65
0.065
0.787
0.5
0.020
0.010
b1
D
E
e
0.25
20
8.5
2.54
0.335
0.100
0.700
e3
F
17.78
7.1
5.1
0.280
0.201
I
L
3.3
0.130
Z
1.27
0.050
9/11
L482
SO16 PACKAGE MECHANICAL DATA
mm
inch
TYP.
DIM.
MIN.
TYP.
MAX.
1.75
0.2
MIN.
MAX.
0.069
0.008
0.063
0.018
0.010
A
a1
a2
b
0.1
0.004
1.6
0.35
0.19
0.46
0.25
0.014
0.007
b1
C
0.5
0.020
c1
D
45° (typ.)
9.8
5.8
10
0.386
0.228
0.394
0.244
E
6.2
e
1.27
8.89
0.050
0.350
e3
F
3.8
0.5
4.0
0.150
0.020
0.157
0.050
0.024
L
1.27
0.62
M
S
8° (max.)
10/11
L482
Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics 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 SGS-THOMSON Microelectronics. Specifica-
tions mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information pre-
viously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or
systems without express written approval of SGS-THOMSON Microelectronics.
1994 SGS-THOMSON Microelectronics - All Rights Reserved
SGS-THOMSON Microelectronics GROUP OF COMPANIES
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