L584 STMICROELECTRONICS | Alldatasheet
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MULTIFUNCTION INJECTION INTERFACE PRELIMINARY DATA .DRIVES ONE OR TWO EXTERNAL DAR- LINGTONS .DUAL AND SINGLE LEVEL CURRENT CON- TROL .SWITCHMODE CURRENT REGULATION .ADJUSTABLE HIGH LEVEL CURRENT DURA- TION .WIDE SUPPLY RANGE (4.75 - 46V) .TTL-COMPATIBLE LOGIC INPUTS .THERMAL PROTECTION .DUMP PROTECTION
DESCRIPTION
The L584 is designed to drive injector solenoids in electronic fuel injection systems and generally in- ductive loads for automotive applications. The de- vice is controlled by two logic inputs and features switchmode regulation of the load current driving an external darlington and an auxiliary one for the cur- rent recirculation. A key feature of the L584 is flexi- bility. It can be used with a variety of darlingtons to match the requirements of the load and it allows both simple and two level currentcontrol. Moreover, DIP16 ( 1 2+2+2 ) ORDERING NUMBER : L584 the drive waveshape can be adjusted by external components. Other features of the device include dump protection, thermal shutdown, a supply vol- tage rangeof 4.75 - 46Vand TTL-compatibleinputs. The L584is suppliedin a 16 lead Powerdippackage which uses the four center pins to conduct heat to the PC board copper. BLOCK DIAGRAM
Symbol Parameter Value Unit R th j-pins Thermal Resistance Junction-pins Max. 15 °C/W R th j-amb Thermal Resistance Junction-ambient Max. 80 °C/W ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value VS DC Supply Voltage (pin 1 open) Positive Transient Voltage (pin 1 connected to VS , πffall time constant = 100ms) (5ms ≤ trise≤ 10ms, Rsource≥ 0.5Ω ) – 0.2V min; +50V Max +60V Max V1 Input Voltage (pins 10, 11) – 0.2V min; +7V Max Vr External Reference Voltage (pin 2) – 0.2V min; +7V Max Vsens Sense Voltage (pin 3) – 0.2V min; +7V Max V8 Max D.C. and Transient Voltage 50V Ir Reference Current (pin 9) 5mA Max Tstg, Tj Storage and Junction Temperature Range –55 to 150 °C PIN CONNECTION * Obtained with the GND pins soldered to printed circuit with minimized copper area. L584
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 The voltage Vsetapplied to this pin sets the holding current level. 3 Sensing Connection for load current sense resistor. Vazlue sets the peak and holding current 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 A capacitor connected between this pin and ground sets the duration of the high level current (t2 in fig. 4) 7 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 See Pin 4. 14 Supply Voltage Supply Voltage Input. 15 NPN Driving Output Current Source for External NPN Darlington (load driver).I dn = 100 Ir (typ.) 16 Internal Clamping Internal Clamp Zener for Fast Turn-off. 000 L584
ELECTRICAL CHARACTERISTICS (Vs (Pin 14) = 14.4V; –40≤ Tj≤ 105°C; Rref = 1.20KΩ unless otherwise specified; refer to fig. 1) Symbol Parameter Test Condiction Min. Typ. Max. Unit VS Operating Supply Voltage Pin 1 Open 4.75 44 V Vd Dump Protection Threshold Pin 1 = V S 28 36 V R d Dump Protection Input Resistance Pin 1 to GND 18 50 k Ω Iq Quiescent Current Pin 14 45 mA Vi Input Threshold Voltages Pin 10, 11 Low High 2.0 0.8 V V I i Input Current Pin 10, 11 Low High –100 –250 µA µA V r Reference Voltage Pin 9 1.15 1.35 V R r Reference Resistor Range Pin 9 to GND Ir =V r/Rr 1 3.3 k Ω I6 Peak Duration Control Current Pin 6 Vpin 6≤ 1.8V Ir/9.50 | I r/6.00 A V6th Peak Duration Control Comparator Threshold Pin 6 1.20 1.6 V V6SAT Pin 6 Saturation Voltage Pin 6 (discharge state) 200 mV I7 Off Duration Control Current Pin 7 Vpin 7≤ 1.8V (Ir min)/9.50 | (Ir max)/6.00 A V7th Off Duration Control Comparator Threshold Pin 7 1.20 1.6 V V7SAT Pin 7 Saturation Voltage Pin 7 (discharge state) 200 mV Vspt Peak Current Threshold Voltage Pin 3 400 500 mV Vset Holding Current Set Voltage Range Pin 2 0 2 V Vset Holding Current Set Voltage Range Pin 3, Peak Value, dV/dt≤ 1V/s Vset– 0.01 Vset+ 0.01 V I3 Pin 3 Bias Current V pin 3= 600mV –200 µA Vcl Recirculation Zener Clamping Voltage Pin 16 to Pin 15 @ 200mA into Pin16 13.5 18.5 V Idn NPN Driver Source Current V pin 15=0 V 7 0xI r | 140 x Ir A Idp PNP Driver Sink Current Vpin 8 ≥ 4.75V 25 x I r |6 0 x Ir A L584
Figure 1: Components Connected to Pins 6 and 7 Determine the Load Current Waveshape. COMPONENTS ON PINS 6 AND 7 LOAD CURRENT WAVEFORM
APPLICATION INFORMATION
Controlledby a logic input and an inhibit input (both TTL compatible), the device drives the external dar- lington(s) to produce a load current waveform as shown in figure 4. This basic waveform shows that the deviceproduces an initial highlevel currentin or- der 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 durationof thehigh level current and the values of thepeakand the holding currents can beadjusted 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- 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 Ip, is set by the sensing re- sistor, 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 =V setth/Rs =( Vset± 10mV)/Rs The peak to hold current ratio is fixed by Vset: Ip /Ihp = 0.45 / Vsetth Vsetis fixed by an external reference and a voltage divider (Vext, R1, R2 in fig 2) : Vset=V ext* R2 / (R1 + R2) Dueto the particulardarlingtonstorage time and the device reaction time not very significant differences can be found betweenIp and Ih values based on the previous formula and the real values seen in the ap- plications. If the holding current function is not used, pin 2 can- not 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 adjustedindependentlyof 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). 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 I r is 1mA which is ob- tained with a 1.2KΩ resistor. The darlington drive currents are given by : PNP : Idp =3 5Ir typ. NPN : Idn =1 0 0Ir 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,b y: V6th–V 6sat C 1 t2 =C 1 = 12 (typ.)I6 Iref The discharge time constant (toffin fig 4) is set by a capacitorC2 between pin7 and ground and is found from : V7th–V 7sat C r toff=C 2 ⋅ =1 2 (typ) I7 Iref Figure 4: Waveforms of the Typical Application Circuit of Fig. 2. L584
Figure 6 :In this application circuit, pin 6 is left open to give a single peak followed by a regulated holding current. Figure 5: When pin 6 is grounded, as shown here, the injector current is regulated at a single level. Io (A) Q1 Q2
10 BDV64 BDV65
I o (A) Q1 Q2
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. Figure 8: Applications circuit using only one darlington with a single level of the injector current. Io (A) Q1 Q2
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 : V pin 16≅ 15V + VBEQ2 + VRsense R9 + R8VCQ2 ≅ Vpin 16. (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 protectthedevice againstthe positiveload dump it is necessary to connect pin 1 to V S. 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 –V 8R 6 > Idp where VDUMP is the dump voltage value and V8 : 4.75V < V8 <4 7 V . For this R6 value, the minimum supply voltageVSmin guaranteeingQ1 operation is given by : VSmin = R6 Ip BQ1 (+2) VBEQ1 R 5 + V8sat In relation to VSmin it is no more verified Idp =3 5Iref (typ) even if the system correct operation is com- pletely guaranteed. The L584 application circuit suggested in these notes allows the use of inductive loads with the low- est possible series resistance (compatible with con- structional requirements)and therefore reducesno- tably the power dissipation. For example, an electronic injector driven from 14.4V which draws 2.4A has a series resistance of 6Ω and dissipates34.56W. Using this circuit a injec- tor with a 1Ω series resistance can be used and the power dissipation is : P d =R LIL2 +V D IL (1 –σ)+V sat⋅ILσ +R S IL2 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 : This given two advantages : the size (and cost) of the injector is reduced and the drive current is re- duced from 2.4A to about 0.4A. The applicationcircuit of figure9 isverysimilar tofig- ure 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 al- ready protected, against load dump transients and vol-tage reversal. Pin 1 must be left open, as shown in fig. 9, if VS is always lower than 46V even during the voltage tran- sients. Note that toffis also related to the required current rippleΔI on the peak or on the holding current level by : (Io – ΔI) RL +V off toff=– l n Io RL +V off Where : Io is the initialcurrent valuein OFF condition (equal to Ip or IH in accordanceto the current level considered), VOFF =V DIODE +V CEQ1 R L is the series resistance value of the induc- tance L : Therefore C2 can be dimensioned directly by : IREF Ll n ( Io – ΔI) RL +V OFF C2 = 12 R L Io R L +V OFF Note that toffis the same for both the peak and hold- ing current. ton time is given by : LV on – R(I1 –ΔI) ton =l nRV on – RI1 where : I1 is the final current value in ON condition (equal to Ip or IH in accordance to the current level considered), R= R L +R SENSE Von =V S –V CE satQ2 If the constant times are respectively LL >2 0 toff and > 20 t onRR it is possible to consider a purely inductive load and therefore : ΔI ΔI toff=L ;t on =LVo Von L R L584
DIP16 PACKAGE MECHANICAL DATA DIM. mm inch a1 0.51 0.020 B 0.77 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 3.3 0.130 Z 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. 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 Australia - Brazil - France - Germany - Hong Kong - Italy - Japan - Korea - Malaysia - Malta - Morocco - The Netherlands - Singapore - Spain - Sweden - Switzerland - Taiwan - Thaliand - United Kingdom - U.S.A. L584