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(R)
L9925
DMOS DUAL FULL BRIDGE DRIVER
2 INDEPENDENTLY CONTROLLED H-BRIDGES RDS,ON <0.9 @ Tamb = 25C, VS = 14V 0.8A DC CURRENT WITHOUT HEAT SINK LOW QUIESCENT MODE Iq <200A THEMAL PROTECTION CROSS CONDUCTION PROTECTION SUPPLY VOLTAGE UP TO 40V CMOS COMPATIBLE INPUTS OUTPUT SHORT-CIRCUIT PROTECTION DESCRIPTION The L9925 is a dual full bridge driver for stepper motor applications. Realized in BCD (Bipolar, CMOS & DOS) techology, logic circuits, precise linear blocks and power transistors are combined to optimize circuit performance and minimize off chip components. Schmitt triggers are used for all input stages and are fully compatible with 5V CMOS logic levels. When both enable signals are low, the IC is commanded to a low quiescent current state and will draw less than 200A from the battery. BLOCK DIAGRAM
SO28 ORDERING NUMBER: L9925
The charge pump is integrated on chip; no external components are required. Full performance is maintaned for 9V OUT1
VS1
OUT2
CHARGE PUMP
CHARGE PUMP
IN1 7V TEMP 7V
IN2
EN1 7V T1 T2
EN1
EN1
1st FULL BRIDGE
T1 T2
EN1
PGND1
GND
5V REGULATOR 40V
VS2
EN2 IN3 IN4
T1 T2
EN2
OUT3
2nd FULL BRIDGE
OUT4
D99AT423
March 1999
................................................................................................... .................................................................................................... ........
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L9925
ABSOLUTE MAXIMUM RATINGS Absolute Maximum Ratings are those values beyond whih damage to the device may occur. Functional operation under these condition isn't implied. For voltages and currents applied externally to the device:
Symbol VVSDC VVSP IOUT IOUT MAX Dc Supply Voltage Supply Voltage Pulse (T 400ms) DC Output Load Current DC Output Current: for VOUT > VVS +0.3V or VOUT < -0.3V the internal DMOS reverse and/or substrate diode become conductive and the applied current should not exceed the specified limit. DC Input Voltage Enable Input Voltage Storage and Junction Temperature Total Power Dissipation (Tpins = 80C) (Tamb = 70C no copper area on PCB) 2 (Tamb =70C 8cm copper area on PCB)
(1)
Parameter
Value -0.3 to 26 40 1.2 1.8
Unit V V A A
VIN1,2 VEN Tstg, Tj Ptot
-0.3 to 7 -0.3 to 7 -40 to 150 5 1.23 2
V V C W W W
(1) Device may be overstressed if pulsed simultaneous with short circuit at one or more of the outputs will be present.
PIN CONNECTION
PGND IN1 EN1 N.C. N.C. OUT1 GND GND OUT3 N.C. N.C. EN2 IN3 PGND
1 2 3 4 5 6 7 8 9 10 11 12 13 14
D88AT424
28 27 26 25 24 23 22 21 20 19 18 17 16 15
N.C. IN2 OUT2 N.C. N.C. VS1 GND GND VS2 N.C. N.C. OUT4 IN4 N.C.
THERMAL DATA
Symbol TjTS TjTSH Rth j-amb Rth j-pins
(2)
Parameter Thermal Shut-down junction temperature min. Thermal Shut-down thereshold hysteresis typ. Thermal Resistance Junction-ambient Thermal Resistance Junction-pins
(2)
Value 150 25 50 15
Unit C C C/W C/W
With 6cm2 on board heat sink area
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L9925
PIN FUNCTIONS
N. 1 2 3 4, 5 6 7, 8 9 10, 11 12 13 14 15 16 17 18, 19 20 21, 22 23 24, 25 26 27 28 Name PGND1 IN1 EN1 NC OUT1 GND OUT3 NC EN2 IN3 PGND2 NC IN4 OUT4 NC VS2 GND VS1 NC OUT2 IN2 NC Ground for DMOS sources in bridge 1 Digital Input from motor controller for bridge 1 Logic enable/disable for bridge 1 (active high) No connect Output of one half of bridge 1 Ground Output of one half of bridge 2 No connect Logic enable/disable for bridge 2 (active high) Digital Input from motor controller for bridge 2 Ground for DMOS sources in bridge 2 No connect Digital Input from motor controller for bridge 2 Output of one half of bridge 2 No connect Supply Voltage for bridge 2 Ground Supply Voltage for bridge 1 No connect Output of one half of bridge 1 Digital Input from motor controller for bridge 1 No connect Function
ELECTRICAL CHARACTERISTICS (VS = 9 to 16V; Tj = -40 to 150C (3) , unless otherwise specified.)
Symbol IS Rds Td-on Td-SB Td-off trise tfall ILo INx, ENx Parameter Quiescent Current Switch on Resistance Turn-on delay Standby setting time Turn-off delay Output rise time (10 to 90%) Output fall time (90 to 10%) Output leakage current Logic Input Low voltage Logic Input High voltage Hysteresis Ibias Input bias current Test Condition EN1 = EN2 =0V; Tj = 85C EN1 = EN2 =5V; Iload = 0A Tj = 25C; VS = 14V; Io =300mA Tj = 125C; VS = 6V; Io =300mA See Fig 1 See Fig 1 See Fig 1 See Fig 1 See Fig 1 EN = 0V; Vo =VS or GND 0.5 0.5 -10 -0.3 3.5 0.5 -50 1.0 5 0.75 1.5 10 50 10 5 5 Min. Typ. Max. 200 12 0.8 1.9 50 200 50 20 20 10 1.5 6 2.0 300 Unit A mA s s s s s mA V V V A
The voltage refered to GND and currents are assumed positive, when the current flows into the pin. (3) Tested up to 125C, parameter guaranted by correlation up to 150C
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L9925
Logic Levels All inputs are positive, non inverting logic
Logic State 0 1 Voltage Range -0.3 to 1.5V 3.5 to 6.0V
Truth Table Enable/ Disable
EN1 0 0 1 1 EN0 0 1 0 1 Bridge 1 Disabled Disabled Enabled Enabled Bridge 2 Disabled Enabled Disabled Enabled Iq <200A <12mA <12mA <12mA
General Operation With the bridge enabled, each input INx, maps directly to the corresponding output OUTx. The output voltage will be equal to the difference between the supply rail and the product of the load current ad the on resistance of the output switch.Vout = Vsupply - (RDS,ON ILOAD). Sourced load currents are positive.
IN1 0 1 OUT1 0 VS IN2 0 1 OUT2 0 VS IN3 0 1 OUT3 0 VS IN4 0 1 OUT4 0 VS
Figure 1. Timing Diagram
STANDBY MODE OPERATING MODE OVERTEMPERATURE STANDBY MODE
EN2
EN1
IN1
IN2
t dSB
tdON
t dOFF
t dSB
OUT1
Tristate 50%
90% Tristate 10% tr t dSB tdOFF tf t dON Tristate
Tristate OUT2 Tristate tr tf
D99AT425
Tristate
t dSB
Figure 2. Typical RON - Characteristics of Source and Sink Stage
RON () 2 VVS=6V VVS=12V
Figure 3. ON - Resistance vs Supply Voltage
RON () IOUT1/2=0.3A 1.9 max for TJ 125C
1.5
1
0.9 0.75
typ. for TJ =25C 6 12 16.5 VVS(V)
-40 -20
0
20
40
60
80 100 120 140 160 T(C)
D99AT426
D99AT427
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L9925
Figure 4. Application Diagram
CEN 100nF CEN 100nF D1 +5V D0 D2 40V CB 100nF CB 40V 100F OUT1 VS1 OUT2 R0 10K
A B
STEPPER MOTOR
D0
R0 10K I/O I/O I/O IN1 IN2 7V TEMP 7V CHARGE PUMP CHARGE PUMP
O
EN1 7V T1 T2
EN1 EN1
P
1st FULL BRIDGE T1 T2 EN1
PGND1
O
GND
5V REGULATOR 40V
VS2
O O O
EN2 IN3 IN4 2nd FULL BRIDGE
T1 T2
EN2
OUT3 CEX 100nF CEX 100nF
OUT4
PGND2
D99AT423
Figure 4 shows a typical application diagram for DC motor driving. To assure the safety of the circuit in the reverse battery condition a reverse protetion diode D1 is necessary. The transient protection diode D2 must assure that themaximum supply voltage VS during the transients at the VBAT line will be limited to a value lower than the absolute maximu ratings for VVSP. The capacities CB are used to lower VS-EMR and its values depend on the driving load. The resistance feedback loop realized by Ro limited to the P power supply line by the diode Do allows open load detection. To protect the device at the outputs against EMI or ESD > 2KV external capacitors Cex may be used. CIRCUIT DESCRIPTION L9925 is a dual full bridge IC designed to drive DC motors, stepper motors and other inductive loads. Eah bridge has 4 power DMOS transistor with RDSon = 0.75 and the relative protection and control circuitry (see fig. 5). Tthe 4 half bridges can be controlled independently by means of the 4 inputs IN1, IN3, IN4 and 2 enable inputs ENABLE1 and ENABLE2.
LOGIC DRIVE (true table for the two full bridges)
INPUTS IN1 IN3 EN1 = EN2 = H L L H H X X IN2 IN4 L H L H X X OUTPUT MOSFETS Sink 1, Sink2 Sink1, Source2 Source1, Sink2 Source1, Source2 All transistors turned OFF All transistors turned OFF
@Tj > 150C EN1 = EN2 = L
L = Low; H = High; X = Don't care CROSS CONDUCTION The device guarantees the absence of cross-conduction by watching internal gate-source voltage of the driving power DMOS. TRANSISTOR OPERATION ON STATE When one of POWER DMOS transistors is ON it can be considered as a resistor RDS(ON) = 0.75 at a junction temperature of 25C
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L9925
In this condition the dissipated power is ginen by: PON = RDS(ON) IDS2 The low RDS(ON) of the Multipower BCD process can provide high currents with low power dissipation. OFF STATE When one of the POWER DMOS transistor is OFF the VDS voltage is equal to the supply voltage and only the leakage current IDSS flows. The power dissipation during this period is given by: POFF = VS IDSS Figure 5a. Two phase chopping TRANSITIONS Like all MOS power transistors the DMOS POWER transistors have an intrinsic diode between their source and drain that can operate as a fast freewheeling diode in switched mode applications. During recirculation with the ENABLE input is low, the POWER MOS is OFF and the diode voltage it is clamped to its characteristics. When the ENABLE input is low, the POWER MOS is OFF and the diode carries all of the recirculation current. The power dissipated in the transitional times in the cycle depends upon the voltage and current waveforms in the application. Ptrans = IDS(t) VDS(t)
EN
EN
IN2 IN1 IN1
IN2
IN1 = H IN2 = L EN1 = H
D99AT429
IN1 = L IN2 = H EN1 = H
D99AT430
Figure 5b. One phase chopping
EN
EN
IN2 IN1 IN1
IN2
IN1 = H IN2 = L EN1 = H
D99AT431
IN1 = H IN2 = H EN1 = H
D99AT432
Figure 5c. Enable chopping
EN
EN
IN2 IN1 IN1
IN2
IN1 = H IN2 = L EN1 = H
D99AT433
IN1 = X IN2 = X EN1 = L
D99AT434
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L9925
THERMAL PROTECTION A thermalprotection circuit has been included that will disable the device if the junction temperature reaches 150C. When the temperature has fallen to a safe level the device restarts under the control of the input and enable signals. APPLICATION INFORMATION RECIRCULATION During recirculationwith the ENALBE input high, the voltage drop across the transistor is RDS(ON). for voltages less than 0.6V and is clamped at a voltages depending on the characteristics of the source-drain diode for greater voltages. Although the device is protected against cross conduction. POWER DISSIPATION each bridge In order to achieve the high performance provided by the L9925 some attention must be paid t ensure that it has an adequate PCB area to dissipate the heat. The forst stage of any thermal design is to calculate the dissipated power in the application, for this example the half step operation shown in Fig. 6 is considered. RISE TIME TR When an arm of the half bridge is turned on current begins to flow in the inductive load until the maximum current IL is reached after a time TR, The dissipated energy EOFF/ON. EOFF/ON = [RDS(ON) IL2 TR] Figure 6.
Tswitch IL
commutation ECOM. As two of the POWER DMOS transistors are ON EON is given by: EON = IL2 RDS(ON) 2 TON In the commutation the energy dissipated is: ECON = VS IL TCOM fSWITCH TON Where: TCOM = Communication Time and it is assumed that:; TCOM = trise = tfall 20s TSWITCH = Chopper frequency FALL TIME TF For this example it is assumed that the energy dissipated in this part of the cycle takes the same form as that shown for the rise time: EOFF/ON = [RDS(ON) IL2 TF] 2 3
QUIESCENT ENERGY The last contribution of the energy dissipation is due to the quiescrent supply current and is given by: EQUIESCENT = IQUIESCENT VS T TOTAL ENERGY PER CYCLE ETOT = (2 EOFF/ON + EON + ECOM) bridge1+ + (2 EOFF/ON + EON + ECOM) bridg2 + EQUIESCENT The total power dissipation PDIS is simply: PDIS = TR = Rise time TON = ON time TF = Fall time TOFF = OFF time T = Period Etot T
2 3
TR
TON
TF
TOFF
D99AT435
ON TIME TON During this time the energy dissipated is due to the ON resistance of the transistors EON and the
T = TR + TON + TF + TOFF
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L9925
DIM. MIN. A a1 b b1 C c1 D E e e3 F L S 7.4 0.4 17.7 10 0.1 0.35 0.23
mm TYP. MAX. 2.65 0.3 0.49 0.32 0.5 45 (typ.) 18.1 10.65 1.27 16.51 7.6 1.27 0.291 0.016 0.697 0.394 0.004 0.014 0.009 MIN.
inch TYP. MAX. 0.104 0.012 0.019 0.013 0.020
OUTLINE AND MECHANICAL DATA
0.713 0.419 0.050 0.65 0.299 0.050
SO28
8 (max.)
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L9925
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. Specification 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. The ST logo is a registered trademark of STMicroelectronics (c) 1999 STMicroelectronics - Printed in Italy - All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - France - Germany - Italy - Japan - Korea - Malaysia - Malta - Mexico - Morocco - The Netherlands Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom - U.S.A.
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