STMICROELECTRONICS L584

L584
MULTIFUNCTION INJECTION INTERFACE
.
.
..
..
..
PRELIMINARY DATA
DRIVES ONE OR TWO EXTERNAL DARLINGTONS
DUAL AND SINGLE LEVEL CURRENT CONTROL
SWITCHMODE CURRENT REGULATION
ADJUSTABLE HIGH LEVEL CURRENT DURATION
WIDE SUPPLY RANGE (4.75 - 46V)
TTL-COMPATIBLE LOGIC INPUTS
THERMAL PROTECTION
DUMP PROTECTION
DIP16 (12 + 2 + 2)
ORDERING NUMBER : L584
DESCRIPTION
The L584 is designed to drive injector solenoids in
electronic fuel injection systems and generally inductive loads for automotive applications. The device is controlled by two logic inputs and features
switchmode regulation of the load current driving an
external darlington and an auxiliary one for the current recirculation. A key feature of the L584 is flexibility. It can be used with a variety of darlingtons to
match the requirements of the load and it allows
both simple and two level current control. Moreover,
the drive waveshape can be adjusted by external
components. Other features of the device include
dump protection, thermal shutdown, a supply voltage rangeof 4.75 - 46V and TTL-compatible inputs.
The L584 is suppliedin a 16 lead Powerdip package
which uses the four center pins to conduct heat to
the PC board copper.
BLOCK DIAGRAM
November 1988
1/13
L584
PIN CONNECTION
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
DC Supply Voltage (pin 1 open)
Positive Transient Voltage
(pin 1 connected to VS, πf fall time constant = 100ms)
(5ms ≤ trise ≤ 10ms, R source ≥ 0.5Ω)
– 0.2V min; +50V Max
V1
Input Voltage (pins 10, 11)
– 0.2V min; +7V Max
Vr
External Reference Voltage (pin 2)
– 0.2V min; +7V Max
Sense Voltage (pin 3)
– 0.2V min; +7V Max
VS
Vsens
V8
Max D.C. and Transient Voltage
Ir
Reference Current (pin 9)
Tstg, Tj
+60V Max
50V
5mA Max
Storage and Junction Temperature Range
–55 to 150°C
THERMAL DATA
Symbol
Parameter
Value
Unit
Rth j-pins
Thermal Resistance Junction-pins
Max.
15
°C/W
Rth j-amb
Thermal Resistance Junction-ambient
Max.
80
°C/W
* Obtained with the GND pins soldered to printed circuit with minimized copper area.
2/13
L584
PIN FUNCTIONS
No
Name
Functions
1
Dump Protection
With pin 1 connected to pin 14 the device is protected against dump voltage ≤ 60V.
The protectio.n operates at VS ≥ 32V (typ.). If this protection is not used the pin must
be left open
2
Holding Current Control
3
Sensing
Connection for load current sense resistor. Vazlue sets the peak and holding current
levels. I P = 0.45/RS (typ.); Ih = Vset/Rs. (see block diagram and fig. 4).
4
Ground
Ground Connection. With pins 5, 12 and 13 conducts heat to pc board copper.
5
Ground
See pin 4.
6
Peak Current Timer
7
The voltage Vset applied to this pin sets the holding current level.
A capacitor connected between this pin and ground sets the duration of the high level
current (t2 in fig. 4)
Discharge Time Constant A capacitor connected between this pin and ground sets the duration of toff (fig. 4). If
grounded, the current switchmode control is suppressed.
8
PNP Driving Output
Current sink for external PNP darlington (for recirculation). Idp = 35 Ir (typ).
9
Reference Voltage
A resistor connected between this pin and ground sets the internal current reference,
Ir. The recommended value is 1.2kΩ giving Ir = 1mA (typ.).
10
Input
TTL-compatible Input. A high level on this pin activates the output, driving the load.
11
Inhibit
TTL-compatible Inhibit Input. A high level on this input disables the output stages and
logic circutry, irrespective of the state of pin 10.
12, 13
Ground
14
Supply Voltage
15
NPN Driving Output
16
Internal Clamping
See Pin 4.
Supply Voltage Input.
Current Source for External NPN Darlington (load driver).Idn = 100 Ir (typ.)
Internal Clamp Zener for Fast Turn-off.
000
3/13
L584
ELECTRICAL CHARACTERISTICS (Vs (Pin 14) = 14.4V; –40 ≤ Tj ≤ 105°C; Rref = 1.20KΩ unless
otherwise specified; refer to fig. 1)
Symbol
Max.
Unit
VS
Operating Supply Voltage
Parameter
Pin 1 Open
Test Condiction
Min.
4.75
Typ.
44
V
Vd
Dump Protection Threshold
Pin 1 = VS
28
36
V
Rd
Dump Protection Input Resistance
Pin 1 to GND
18
50
kΩ
Iq
Quiescent Current
Pin 14
45
mA
Vi
Input Threshold Voltages
Pin 10, 11
Low
High
0.8
V
V
Ii
Input Current
2.0
Pin 10, 11
Low
High
–100
–250
µA
µA
Vr
Reference Voltage
Pin 9
1.15
1.35
V
Rr
Reference Resistor Range
Pin 9 to GND
Ir = V r/Rr
1
3.3
kΩ
I6
Peak Duration Control Current
Pin 6
Vpin 6 ≤ 1.8V
Ir/9.50
Ir/6.00
A
Peak Duration Control
Comparator Threshold
Pin 6
1.6
V
Pin 6 Saturation Voltage
Pin 6
(discharge state)
200
mV
Off Duration Control Current
Pin 7
Vpin 7 ≤ 1.8V
Off Duration Control
Comparator Threshold
Pin 7
Pin 7 Saturation Voltage
Pin 7
(discharge state)
Vspt
Peak Current Threshold Voltage
Pin 3
Vset
Holding Current Set Voltage Range Pin 2
Vset
V6th
V6SAT
I7
V7th
V7SAT
4/13
|
|
1.20
(Ir min)/9.50 | (Ir max)/6.00
|
1.6
V
200
mV
400
500
mV
0
2
V
Holding Current Set Voltage Range Pin 3, Peak Value, dV/dt ≤ 1V/s
Vset –
0.01
Vset +
0.01
V
–200
I3
Pin 3 Bias Current
Vcl
Recirculation
Voltage
Idn
NPN Driver Source Current
Vpin 15 = 0V
Idp
PNP Driver Sink Current
Vpin 8 ≥ 4.75V
Zener
Vpin 3 = 600mV
Clamping Pin 16 to Pin 15 @ 200mA into Pin16
1.20
A
µA
13.5
70 x Ir
25 x Ir
18.5
V
|
140 x Ir
A
|
60 x Ir
A
L584
APPLICATION INFORMATION
Controlled by a logic input and an inhibit input (both
TTL compatible), the device drives the external darlington(s) to produce a load current waveform as
shown in figure 4. This basic waveform shows that
the device produces an initial high level current in order to ensure a fast opening, followed by a holding
level current as long as the input is active. Both
the peak and holding current are regulated by the
L584’s switchmode circuitry.
The duration of the high level current and the values
of the peak and the holding currents can be adjusted
by external components.
Moreover, by omitting C1, C2 or both it is possible
to realize single-level current control, a transitory
peak followed by a regulated holding current or a
simple peak (figure 1).
The peak and holding current values are always re-
Figure 1 : Components Connected to Pins 6 and 7 Determine the Load Current Waveshape.
COMPONENTS ON PINS 6 AND 7
LOAD CURRENT WAVEFORM
5/13
L584
ferred, in the following formula, to IE, emitter current
of the external darlington Q2,
IE = ILOAD + Idn
because the sensing detection is on the darlington
emitter (not directly on the load).
The peak current level I p, is set by the sensing resistor, Rs, and is found from :
Ip = 0.45 / Rs (typ)
The peak value of holding current level, Ih, is set by
a voltage (Vset) applied to pin 2, giving :
Ihp = Vsetth / Rs = (Vset ± 10mV)/Rs
The peak to hold current ratio is fixed by Vset :
Ip / I hp = 0.45 / Vsetth
Vset is fixed by an external reference and a voltage
divider (Vext, R1, R2 in fig 2) :
Vset = Vext * R2 / (R1 + R2)
Due to the particular darlington storage time and the
device reaction time not very significant differences
can be found between Ip and Ih values based on the
previous formula and the real values seen in the applications.
If the holding current function is not used, pin 2 cannot be left floatingand it must be connectedto GND.
Figure 2 : Application Circuit Showing the Optional Components. In particular it illustrates how the holding
current level is adjusted independentlyof the peak current (with R1, R2, Vext) and how the internal
zener clamp is connected. This circuit produces the waveforms shown in Fig. 4.
Io (A)
Q1
Q2
4
BDX54
BDX53
8
BDW94
BDW93
12
BDV64
BDV65
Figure 3 : P.C. Board and Components Layout of the Circuit of Fig. 2 (1 : 1 scale).
6/13
L584
The drive current for the two darlingtons and the
waveform time constants are all defined in turn by a
resistor between pin 9 and ground.
The recommended value for Ir is 1mA which is obtained with a 1.2KΩ resistor. The darlington drive
currents are given by :
PNP : Idp = 35 Ir typ. NPN : Idn = 100 Ir typ.
The duration of the high current level (t2 in fig 4) is
set by a capacitor connected between pin 6 and
ground. This capacitor, C1 is related to the duration,
t2, by :
C1
V6th – V6sat
t2 = C1
= 12
(typ.)
Iref
I6
The discharge time constant (toff in fig 4) is set by a
capacitor C2 between pin 7 and ground and is found
from :
Cr
V7th – V7sat
(typ)
toff = C2 ⋅
= 12
Iref
I7
Figure 4 : Waveforms of the Typical Application Circuit of Fig. 2.
7/13
L584
Figure 5 : When pin 6 is grounded, as shown here, the injector current is regulated at a single level.
Io (A)
Q1
Q2
4
BDX54
BDX53
8
BDW94
BDW93
10
BDV64
BDV65
Figure 6 : In this application circuit, pin 6 is left open to give a single peak followed by a regulated holding
current.
Io (A)
8/13
Q1
Q2
4
BDX54
BDX53
8
BDW94
BDW93
10
BDV64
BDV65
L584
Figure 7 : Switchmode control of the current can be suppressed entirely by leaving pin 6 open and
grounding pin 7. the peak current is still controlled.
Io (A)
Q1
Q2
4
BDX54
BDX53
8
BDW94
BDW93
10
BDV64
BDV65
Figure 8 : Applications circuit using only one darlington with a single level of the injector current.
9/13
L584
To have a very short off time when the L584 input
goes LOW, an internal zener is available on pin 16.
This zener is used with an external divider, R8, R9,
as shown in figure 2. Suitable values can be found
from :
Vpin 16 ≅ 15V + VBEQ2 + VRsense
R9 + R8
VCQ2 ≅ Vpin 16 .
R8
(VCQ2 is the voltage at the collector of Q2. VCQ2 max
is 47V if the pin 8 is used for slow recirculation as in
fig. 2).
To ensure stability, a small capacitor (about 200pF)
must be connected between the base and collector
of Q2 when pin 16 is used.
A different opportunityfor a fast off time is based on
the use of the external zener diode Dz. In this case
also the maximum Dz voltage value is 47V.
LOAD DUMP PROTECTION
To protect the device against the positive load dump
it is necessary to connect pin 1 to VS. In this case,
if VS is higher than 32V, the device turns off Q2 and
turns on Q1. The external resistor R6 must be used
(see application circuit) to avoid that pin 8 voltage
exceeds 50V during load dump. R6 must be :
VDUMP – V8
R6 >
Idp
where VDUMP is the dump voltage value and V8 :
4.75V < V8 < 47V.
For this R6 value, the minimum supply voltage VSmin
guaranteeing Q1 operation is given by :
10/13
VBEQ1 
 Ip
+ V8sat
VSmin = R6 
(+2)
R5 
 BQ1
In relation to VSmin it is no more verified Idp = 35 Iref
(typ) even if the system correct operation is completely guaranteed.
The L584 application circuit suggested in these
notes allows the use of inductive loads with the lowest possible series resistance (compatible with constructional requirements) and therefore reduces notably the power dissipation.
For example, an electronic injector driven from
14.4V which draws 2.4A has a series resistance of
6Ω and dissipates 34.56W. Using this circuit a injector with a 1Ω series resistance can be used and the
power dissipation is :
2
2
Pd = RLIL + VDIL (1 – σ) + Vsat ⋅ IL σ + RS IL σ
where RL = resistance of injector = 1Ω
VD = drop across diode, VD ≅ 1V
Vsat = saturation voltage of Q2, ≅ 1V
RS = R11 = 185mΩ
σ = duty cycle = 20%
therefore :
Pd ≅ 5.76 + 1.92 + 0.48 + 0.21 = 8.37W
This given two advantages : the size (and cost) of
the injector is reduced and the drive current is reduced from 2.4A to about 0.4A.
The applicationcircuit of figure 9 isvery similar to figure 2 except that it shows the use of two supplies :
one for the control circuit, one for the power stage.
L584
Figure 9 : Application circuit showing how two separate supplies can be used.
In this application it is assumed that the 5V supply
for L584 is taken from a logic supply, which is already protected, against load dump transients and
vol-tage reversal.
Pin 1 must be left open, as shown in fig. 9, if VS is
L lower than 46V even during the voltage tranalways
R
sients.
Note that toff is also related to the required current
ripple ∆I on the peak or on the holding current level
by :
(Io – ∆I) RL + Voff
toff = –
ln
Io RL + Voff
Where : Io is the initial current valuein OFF condition
(equal to Ip or IH in accordance to the current level
considered),
VOFF = VDIODE + VCEQ1
RL is the series resistance value of the inductance L :
Therefore C2 can be dimensioned directly by :
ln (Io – ∆I) RL + VOFF
IREF L
Io RL + VOFF
12
RL
Note that toff is the same for both the peak and holding current.
ton time is given by :
L
Von – R(I1 – ∆I)
ton =
ln
R
Von – RI1
where : I1 is the final current value in ON condition
(equal to Ip or IH in accordance to the current level
considered),
R = RL + RSENSE
Von = VS – VCEsatQ2
If the constant times are respectively
L
L
> 20 toff and
> 20 ton
R
R
it is possible to consider a purely inductive load and
therefore :
∆I
∆I
toff = L
; ton = L
Vo
Von
C2 =
11/13
L584
DIP16 PACKAGE MECHANICAL DATA
mm
DIM.
MIN.
a1
0.51
B
0.77
TYP.
MAX.
MIN.
TYP.
MAX.
0.020
1.65
0.030
0.065
b
0.5
0.020
b1
0.25
0.010
D
20
0.787
E
8.5
0.335
e
2.54
0.100
e3
17.78
0.700
F
7.1
0.280
I
5.1
0.201
L
Z
12/13
inch
3.3
0.130
1.27
0.050
L584
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. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously 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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