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L6229
DMOS DRIVER FOR THREE-PHASE BRUSHLESS DC MOTOR
1

FEATURES
OPERATING SUPPLY VOLTAGE FROM 8 TO 52V 2.8A OUTPUT PEAK CURRENT (1.4A DC) RDS(ON) 0.73 TYP. VALUE @ Tj = 25 C OPERATING FREQUENCY UP TO 100KHz NON DISSIPATIVE OVERCURRENT DETECTION AND PROTECTION DIAGNOSTIC OUTPUT CONSTANT tOFF PWM CURRENT CONTROLLER SLOW DECAY SYNCHR. RECTIFICATION 60 & 120 HALL EFFECT DECODING LOGIC BRAKE FUNCTION TACHO OUTPUT FOR SPEED LOOP CROSS CONDUCTION PROTECTION THERMAL SHUTDOWN UNDERVOLTAGE LOCKOUT INTEGRATED FAST FREEWEELING DIODES
Figure 1. Package
PowerDIP24 (20+2+2)
PowerSO36
2
DESCRIPTION
SO24 (20+2+2)
The L6229 is a DMOS Fully Integrated Three-Phase Motor Driver with Overcurrent Protection. Realized in MultiPower-BCD technology, the device combines isolated DMOS Power Transistors with CMOS and bipolar circuits on the same chip. The device includes all the circuitry needed to drive a three-phase BLDC motor including: a three-phase DMOS Bridge, a constant off time PWM Current Controller and the decoding logic for single ended hall sensors that generates the required sequence for the power stage. Available in PowerDIP24 (20+2+2), PowerSO36 and SO24 (20+2+2) packages, the L6229 features a non-
Table 1. Order Codes
Part Number L6229N L6229PD L6229PDTR L6229D L6229DTR Package PowerDIP24 PowerSO36 PowerSO36 in Tape & Reel SO24 SO24 in Tape & Reel
dissipative overcurrent protection on the high side Power MOSFETs and thermal shutdown.
October 2004
Rev. 3 1/25
L6229
Figure 2. Block Diagram
VBOOT VCP VBOOT CHARGE PUMP THERMAL PROTECTION OCD1 DIAG OCD OCD1 OCD2 OCD EN BRAKE FWD/REV OCD2 H3 H2 H1 HALL-EFFECT SENSORS DECODING LOGIC GATE LOGIC 10V OUT2 OCD3 VBOOT 10V OUT1 VBOOT VSA
SENSEA VBOOT VSB
RCPULSE
TACHO MONOSTABLE
OCD3 10V
OUT3
TACHO 10V 5V PWM VOLTAGE REGULATOR ONE SHOT MONOSTABLE MASKING TIME + SENSE COMPARATOR VREF SENSEB
RCOFF
D99IN1095B
Table 2. Absolute Maximum Ratings
Symbol VS VOD Parameter Supply Voltage Differential Voltage between: VSA, OUT1, OUT2, SENSEA and VSB, OUT3, SENSEB Bootstrap Peak Voltage Logic Inputs Voltage Range Voltage Range at pin VREF Voltage Range at pin RCOFF Voltage Range at pin RCPULSE Voltage Range at pins SENSEA and SENSEB Pulsed Supply Current (for each VSA and VSB pin) DC Supply Current (for each VSA and VSB pin) Storage and Operating Temperature Range VSA = VSB = VS; TPULSE < 1ms VSA = VSB = VS Test conditions VSA = VSB = VS VSA = VSB = VS = 60V; VSENSEA = VSENSEB = GND VSA = VSB = VS Value 60 60 Unit V V
VBOOT VIN, VEN VREF VRCOFF VRCPULSE VSENSE IS(peak) IS Tstg, TOP
VS + 10 -0.3 to 7 -0.3 to 7 -0.3 to 7 -0.3 to 7 -1 to 4 3.55 1.4 -40 to 150
V V V V V V A A C
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L6229
Table 3. Recommended Operating Condition
Symbol VS VOD Parameter Supply Voltage Differential Voltage between: VSA, OUT1, OUT2, SENSEA and VSB, OUT3, SENSEB Voltage Range at pin VREF Voltage Range at pins SENSEA and SENSEB DC Output Current Operating Junction Temperature Switching Frequency (pulsed tW < trr) (DC) VSA = VSB = VS -25 Test Conditions VSA = VSB = VS VSA = VSB = VS; VSENSEA = VSENSEB -0.1 -6 -1 MIN 12 MAX 52 52 Unit V V
VREF VSENSE IOUT TJ fSW
5 6 1 1.4 125 100
V V V A C KHz
Table 4. Thermal Data
Symbol Rth(j-pins) Rth(j-case) Rth(j-amb)1 Rth(j-amb)1 Rth(j-amb)1 Rth(j-amb)2 Description Maximum Thermal Resistance Junction-Pins Maximum Thermal Resistance Junction-Case MaximumThermal Resistance Junction-Ambient (1) Maximum Thermal Resistance Junction-Ambient (2) MaximumThermal Resistance Junction-Ambient (3) Maximum Thermal Resistance Junction-Ambient (4) 44 59 55 78 PDIP24 19 SO24 15 2 36 16 63 PowerSO36 Unit C/W C/W C/W C/W C/W C/W
(1) Mounted on a multi-layer FR4 PCB with a dissipating copper surface on the bottom side of 6 cm2 (with a thickness of 35 m). (2) Mounted on a multi-layer FR4 PCB with a dissipating copper surface on the top side of 6 cm2 (with a thickness of 35 m). (3) Mounted on a multi-layer FR4 PCB with a dissipating copper surface on the top side of 6 cm2 (with a thickness of 35 m), 16 via holes and a ground layer. (4) Mounted on a multi-layer FR4 PCB without any heat-sinking surface on the board.
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L6229
Figure 3. Pin Connections (Top view)
GND N.C.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
D01IN1195A
36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19
GND N.C. N.C. VSB OUT3 N.C. VBOOT BRAKE VREF EN FWD/REV SENSEB RCPULSE N.C. TACHO N.C. N.C. GND
H1 DIAG SENSEA RCOFF OUT1 GND GND TACHO RCPULSE SENSEB FWD/REV EN
1 2 3 4 5 6 7 8 9 10 11 12
D01IN1194A
24 23 22 21 20 19 18 17 16 15 14 13
H3 H2 VCP OUT2 VSA GND GND VSB OUT3 VBOOT BRAKE VREF
N.C. VSA OUT2 N.C. VCP H2 H3 H1 DIAG SENSEA RCOFF N.C. OUT1 N.C. N.C. GND
PowerDIP24/SO24
(5) The slug is internally connected to pins 1, 18, 19 and 36 (GND pins).
PowerSO36 (5)
Table 5. Pin Description
PACKAGE SO24/ PowerDIP24 PIN # 1 2 PowerSO36 PIN # 10 11 H1 DIAG Sensor Input Open Drain Output Single Ended Hall Effect Sensor Input 1. Overcurrent Detection and Thermal Protection pin. An internal open drain transistor pulls to GND when an overcurrent on one of the High Side MOSFETs is detected or during Thermal Protection. Name Type Function
3
12
SENSEA
Power Supply Half Bridge 1 and Half Bridge 2 Source Pin. This pin must be connected together with pin SENSEB to Power Ground through a sensing power resistor. RC Pin RC Network Pin. A parallel RC network connected between this pin and ground sets the Current Controller OFF-Time. Output 1 Ground terminals. On PowerDIP24 and SO24 packages, these pins are also used for heat dissipation toward the PCB. On PowerSO36 package the slug is connected on these pins. Frequency-to-Voltage open drain output. Every pulse from pin H1 is shaped as a fixed and adjustable length pulse. RC Network Pin. A parallel RC network connected between this pin and ground sets the duration of the Monostable Pulse used for the Frequency-to-Voltage converter.
4
13
RCOFF
5 6, 7, 18, 19
15 1, 18, 19, 36
OUT1 GND
Power Output GND
8
22
TACHO
Open Drain Output RC Pin
9
24
RCPULSE
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Table 5. Pin Description (continued)
PACKAGE SO24/ PowerDIP24 PIN # 10 PowerSO36 PIN # 25 SENSEB Power Supply Half Bridge 3 Source Pin. This pin must be connected together with pin SENSEA to Power Ground through a sensing power resistor. At this pin also the Inverting Input of the Sense Comparator is connected. Logic Input Selects the direction of the rotation. HIGH logic level sets Forward Operation, whereas LOW logic level sets Reverse Operation. If not used, it has to be connected to GND or +5V.. Chip Enable. LOW logic level switches OFF all Power MOSFETs. If not used, it has to be connected to +5V. Current Controller Reference Voltage. Do not leave this pin open or connect to GND. Brake Input pin. LOW logic level switches ON all High Side Power MOSFETs, implementing the Brake Function. If not used, it has to be connected to +5V. Name Type Function
11
26
FWD/REV
12
27
EN
Logic Input
13 14
28 29
VREF BRAKE
Logic Input Logic Input
15 16 17 20
30 32 33 4
VBOOT OUT3 VSB VSA
Supply Voltage Bootstrap Voltage needed for driving the upper Power MOSFETs. Power Output Output 3. Power Supply Half Bridge 3 Power Supply Voltage. It must be connected to the supply voltage together with pin VSA. Power Supply Half Bridge 1 and Half Bridge 2 Power Supply Voltage. It must be connected to the supply voltage together with pin VSB. Power Output Output Sensor Input Sensor Input Output 2. Charge Pump Oscillator Output. Single Ended Hall Effect Sensor Input 2. Single Ended Hall Effect Sensor Input 3.
21 22 23 24
5 7 8 9
OUT2 VCP H2 H3
Table 6. Electrical Characteristics (VS = 48V , Tamb = 25 C , unless otherwise specified)
Symbol Parameter Test Conditions Min 5.8 5 All Bridges OFF; Tj = -25 to 125C
(6)
Typ 6.3 5.5 5 165
Max 6.8 6 10
Unit V V mA C mA mA
VSth(ON) Turn ON threshold VSth(OFF) Turn OFF threshold IS TJ(OFF) Quiescent Supply Current Thermal Shutdown Temperature
Output DMOS Transistors RDS(ON) High-Side + Low-Side Switch ON Resistance IDSS Leakage Current Tj = 25 C Tj =125 C
(7)
1.47 2.35
1.69 2.70 2
EN = Low; OUT = VCC EN = Low; OUT = GND -0.3
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Table 6. Electrical Characteristics (continued) (VS = 48V , Tamb = 25 C , unless otherwise specified)
Symbol Source Drain Diodes VSD trr tfr Forward ON Voltage Reverse Recovery Time Forward Recovery Time ISD = 1.4A, EN = LOW If = 1.4A 1.15 300 200 1.3 V ns ns Parameter Test Conditions Min Typ Max Unit
Logic Input (H1, H2, H3, EN, FWD/REV, BRAKE) VIL VIH IIL IIH Vth(ON) Low level logic input voltage High level logic input voltage Low level logic input current High level logic input current Turn-ON Input Threshold 0.8 0.25 GND Logic Input Voltage 7V Logic Input Voltage 1.8 1.3 0.5 -0.3 2 -10 10 2.0 0.8 7 V V A A V V V
Vth(OFF) Turn-OFF Input Threshold VthHYS Input Thresholds Hysteresys
Switching Characteristics tD(on)EN tD(off)EN tD(on)IN tD(off)IN tRISE tFALL tDT fCP Enable to out turn-ON delay time (7) ILOAD = 1.4 A, Resistive Load Enable to out turn-OFF delay time (7) ILOAD = 1.4 A, Resistive Load Other Logic Inputs to Output TurnON delay Time ILOAD = 1.4 A, Resistive Load 500 500 1.6 800 40 40 0.5 Tj = -25 to 125C
(6)
650
800 1000
ns ns s ns
Other Logic Inputs to out Turn-OFF ILOAD = 1.4 A, Resistive Load delay Time Output Rise Time (7) Output Fall Time (7) Dead Time Charge Pump Frequency ILOAD = 1.4 A, Resistive Load ILOAD = 1.4 A, Resistive Load
250 250 1 0.6 1
ns ns s MHz
PWM Comparator and Monostable IRCOFF Source current at pin RCOFF VRCOFF = 2.5 V Vref = 0.5 V Vref = 0.5 V 3.5 5.5 5 500 1 2.5 ROFF= 20k ; COFF =1nF ROFF= 100k ; COFF =1nF IBIAS Input Bias Current at pin VREF 13 61 10 3 mA mV ns s s s s A
VOFFSET Offset Voltage on Sense Comparator tprop tblank tON(min) tOFF Turn OFF Propagation delay (8) Internal Blanking Time on Sense Comparator Minimum on Time PWM RecirculationTime
Tacho Monostable IRCPULSE Source Current at pin RCPULSE VRCPULSE = 2.5V 3.5 5.5 mA
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Table 6. Electrical Characteristics (continued) (VS = 48V , Tamb = 25 C , unless otherwise specified)
Symbol tPULSE Parameter Monostable of Time Test Conditions RPUL = 20k ; CPUL =1nF RPUL = 100k ; CPUL =1nF RTACHO Open Drain ON Resistance Over Current Detection & Protection ISOVER ROPDR IOH Supply Overcurrent Protection Threshold Open Drain ON Resistance OCD high level leakage current TJ = -25 to 125C (6) IDIAG = 4mA VDIAG = 5V IDIAG = 4mA; CDIAG < 100pF IDIAG = 4mA; CDIAG < 100pF 2 2.8 40 1 200 100 3.55 60 A A ns ns Min Typ 12 60 40 60 Max Unit s s
tOCD(ON) OCD Turn-ON Delay Time (9) tOCD(OFF) OCD Turn-OFF Delay Time (9)
(6) Tested at 25C in a restricted range and guaranteed by characterization. (7) See Fig. 4. (8) Measured applying a voltage of 1V to pin SENSE and a voltage drop from 2V to 0V to pin VREF. (9) See Fig. 5.
Figure 4. Switching Characteristic Definition
EN
Vth(ON) Vth(OFF) t IOUT 90%
10%
D01IN1316
t tFALL tD(OFF)EN tD(ON)EN tRISE
Figure 5. Overcurrent Detection Timing Definition
IOUT ISOVER
ON BRIDGE OFF VDIAG 90%
10% tOCD(ON) tOCD(OFF)
D02IN1387
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3
CIRCUIT DESCRIPTION
3.1 POWER STAGES and CHARGE PUMP The L6229 integrates a Three-Phase Bridge, which consists of 6 Power MOSFETs connected as shown on the Block Diagram. Each Power MOS has an RDS(ON) = 0.73 (typical value @25C) with intrinsic fast freewheeling diode. Switching patterns are generated by the PWM Current Controller and the Hall Effect Sensor Decoding Logic (see relative paragraphs). Cross conduction protection is implemented by using a dead time (tDT = 1s typical value) set by internal timing circuit between the turn off and turn on of two Power MOSFETs in one leg of a bridge. Pins VSA and VSB MUST be connected together to the supply voltage (VS). Using N-Channel Power MOS for the upper transistors in the bridge requires a gate drive voltage above the power supply voltage. The Bootstrapped Supply (VBOOT) is obtained through an internal oscillator and few external components to realize a charge pump circuit as shown in Figure 6. The oscillator output (pin VCP) is a square wave at 600KHz (typically) with 10V amplitude. Recommended values/part numbers for the charge pump circuit are shown in Table 7. Table 7. Charge Pump External Component Values.
CBOOT CP RP D1 D2 220nF 10nF 100 1N4148 1N4148
Figure 6. Charge Pump Circuit
VS D1 D2 RP CP VCP VBOOT VSA VSB
D01IN1328
CBOOT
3.2 LOGIC INPUTS Pins FWD/REV, BRAKE, EN, H1, H2 and H3 are TTL/CMOS and C compatible logic inputs. The internal structure is shown in Figure 4. Typical value for turn-ON and turn-OFF thresholds are respectively Vth(ON) = 1.8V and Vth(OFF) = 1.3V. Pin EN (enable) may be used to implement Overcurrent and Thermal protection by connecting it to the open collector DIAG output If the protection and an external disable function are both desired, the appropriate connection must be implemented. When the external signal is from an open collector output, the circuit in Figure 8 can be used . For external circuits that are push pull outputs the circuit in Figure 9 could be used. The resistor REN should be chosen in the range from 2.2K to 180K. Recommended values for REN and CEN are respectively 100K and 5.6nF. More information for selecting the values can be found in the Overcurrent Protection section.
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L6229
Figure 7. Logic Input Internal Structure
5V
ESD PROTECTION
D01IN1329
Figure 8. Pin EN Open Collector Driving
5V REN OPEN COLLECTOR OUTPUT DIAG 5V
CEN
EN ESD PROTECTION
D02IN1378
Figure 9. Pin EN Push-Pull Driving
DIAG 5V REN EN CEN ESD PROTECTION
D02IN1379
PUSH-PULL OUTPUT
3.3 PWM CURRENT CONTROL The L6229 includes a constant off time PWM Current Controller. The current control circuit senses the bridge current by sensing the voltage drop across an external sense resistor connected between the source of the three lower power MOS transistors and ground, as shown in Figure 10. As the current in the motor increases the voltage across the sense resistor increases proportionally. When the voltage drop across the sense resistor becomes greater than the voltage at the reference input pin VREF the sense comparator triggers the monostable switching the bridge off. The power MOS remain off for the time set by the monostable and the motor current recirculates around the upper half of the bridge in Slow Decay Mode as described in the next section. When the monostable times out, the bridge will again turn on. Since the internal dead time, used to prevent cross conduction in the bridge, delays the turn on of the power MOS, the effective Off Time tOFF is the sum of the monostable time plus the dead time. Figure 11 shows the typical operating waveforms of the output current, the voltage drop across the sensing resistor, the pin RC voltage and the status of the bridge. More details regarding the Synchronous Rectification and the output stage configuration are included in the next section. Immediately after the Power MOS turn on, a high peak current flows through the sense resistor due to the re-
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L6229
verse recovery of the freewheeling diodes. The L6229 provides a 1s Blanking Time tBLANK that inhibits the comparator output so that the current spike cannot prematurely retrigger the monostable. Figure 10. PWM Current Controller Simplified Schematic
VSB BLANKING TIME MONOSTABLE 1s FROM THE LOW-SIDE GATE DRIVERS VSA VS
TO GATE LOGIC
5mA S (0) (1) Q R
MONOSTABLE SET BLANKER OUT2 OUT3 DRIVERS + DEAD TIME DRIVERS + DEAD TIME OUT1 DRIVERS + DEAD TIME
5V 2.5V +
+ SENSE COMPARATOR RCOFF COFF ROFF -
VREF RSENSE
SENSEB
SENSEA
D02IN1380
Figure 11. Output Current Regulation Waveforms
IOUT VREF RSENSE tOFF tON tOFF
VSENSE VREF 0
1s tBLANK
1s tBLANK
Slow Decay
Slow Decay
VRC 5V 2.5V
tRCRISE
tRCRISE
tRCFALL 1s tDT ON
SYNCHRONOUS RECTIFICATION
D02IN1351
tRCFALL 1s tDT
OFF
B
C
D
A
B
C
D
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Figure 12 shows the magnitude of the Off Time tOFF versus COFF and ROFF values. It can be approximately calculated from the equations: tRCFALL = 0.6 * ROFF * COFF tOFF = tRCFALL + tDT = 0.6 * ROFF * COFF + tDT where ROFF and COFF are the external component values and tDT is the internally generated Dead Time with: 20K ROFF 100K 0.47nF COFF 100nF tDT = 1s (typical value) Therefore: tOFF(MIN) = 6.6s tOFF(MAX) = 6ms These values allow a sufficient range of tOFF to implement the drive circuit for most motors. The capacitor value chosen for COFF also affects the Rise Time tRCRISE of the voltage at the pin RCOFF. The Rise Time tRCRISE will only be an issue if the capacitor is not completely charged before the next time the monostable is triggered. Therefore, the On Time tON, which depends by motors and supply parameters, has to be bigger than tRCRISE for allowing a good current regulation by the PWM stage. Furthermore, the On Time tON can not be smaller than the minimum on time tON(MIN). t O N > tON ( MI N ) = 2.5s (typ. value) tON > tRC R ISE - tDT tRCRISE = 600 * COFF Figure 13 shows the lower limit for the On Time tON for having a good PWM current regulation capacity. It has to be said that tON is always bigger than tON(MIN) because the device imposes this condition, but it can be smaller than tRCRISE - tDT. In this last case the device continues to work but the Off Time tOFF is not more constant. So, small COFF value gives more flexibility for the applications (allows smaller On Time and, therefore, higher switching frequency), but, the smaller is the value for COFF, the more influential will be the noises on the circuit performance. Figure 12. tOFF versus COFF and ROFF.
1 .10
4
R off = 100k
3
1 .10
R off = 47k R off = 20k
toff [s]
100
10
1
0.1
1 Coff [nF]
10
100
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Figure 13. Area where tON can vary maintaining the PWM regulation.
100
ton(min) [s]
10
1.5s (typ. value)
1 0.1
1 Coff [nF]
10
100
3.4 SLOW DECAY MODE Figure 14 shows the operation of the bridge in the Slow Decay mode during the Off Time. At any time only two legs of the three-phase bridge are active, therefore only the two active legs of the bridge are shown in the figure and the third leg will be off. At the start of the Off Time, the lower power MOS is switched off and the current recirculates around the upper half of the bridge. Since the voltage across the coil is low, the current decays slowly. After the Dead Time the upper power MOS is operated in the synchronous rectification mode reducing the impendence of the freewheeling diode and the related conducting losses. When the monostable times out, upper MOS that was operating the synchronous mode turns off and the lower power MOS is turned on again after some delay set by the Dead Time to prevent cross conduction. Figure 14. Slow Decay Mode Output Stage Configurations
A) ON TIME
D01IN1336
B) 1s DEAD TIME
C) SYNCHRONOUS RECTIFICATION
D) 1s DEAD TIME
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3.5 DECODING LOGIC The Decoding Logic section is a combinatory logic that provides the appropriate driving of the three-phase bridge outputs according to the signals coming from the three Hall Sensors that detect rotor position in a 3phase BLDC motor. This novel combinatory logic discriminates between the actual sensor positions for sensors spaced at 60, 120, 240 and 300 electrical degrees. This decoding method allows the implementation of a universal IC without dedicating pins to select the sensor configuration. There are eight possible input combinations for three sensor inputs. Six combinations are valid for rotor positions with 120 electrical degrees sensor phasing (see Figure 15, positions 1, 2, 3a, 4, 5 and 6a) and six combinations are valid for rotor positions with 60 electrical degrees phasing (see Figure 17, positions 1, 2, 3b, 4, 5 and 6b). Four of them are in common (1, 2, 4 and 5) whereas there are two combinations used only in 120 electrical degrees sensor phasing (3a and 6a) and two combinations used only in 60 electrical degrees sensor phasing (3b and 6b). The decoder can drive motors with different sensor configuration simply by following the Table 8. For any input configuration (H1, H2 and H3) there is one output configuration (OUT1, OUT2 and OUT3). The output configuration 3a is the same than 3b and analogously output configuration 6a is the same than 6b. The sequence of the Hall codes for 300 electrical degrees phasing is the reverse of 60 and the sequence of the Hall codes for 240 phasing is the reverse of 120. So, by decoding the 60 and the 120 codes it is possible to drive the motor with all the four conventions by changing the direction set. Table 8. 60 and 120 Electrical Degree Decoding Logic in Forward Direction.
Hall 120 Hall 60 H1 H2 H3 OUT1 OUT2 OUT3 Phasing 1 1 H L L Vs High Z GND 1->3 2 2 H H L High Z Vs GND 2->3 3a L H L GND Vs High Z 2->1 3b H H H GND Vs High Z 2->1 4 4 L H H GND High Z Vs 3->1 5 5 L L H High Z GND Vs 3->2 6a H L H Vs GND High Z 1->2 6b L L L Vs GND High Z 1->2
Figure 15. 120 Hall Sensor Sequence.
H1 H1 H1 H1 H1 H1
H3
H2
H3
H2
H3
H2
H3
H2
H3
H2
H3
H2
1
=H =L
2
3a
4
5
6a
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L6229
Figure 16. 60 Hall Sensor Sequence.
H1
H1
H1
H1
H1
H1
H2 H3 H3
H2 H3
H2 H3
H2 H3
H2 H3
H2
1
=H =L
2
3b
4
5
6b
3.6 TACHO A tachometer function consists of a monostable, with constant off time (tPULSE), whose input is one Hall Effect signal (H1). It allows developing an easy speed control loop by using an external op amp, as shown in Figure 18. For component values refer to Application Information section. The monostable output drives an open drain output pin (TACHO). At each rising edge of the Hall Effect Sensors H1, the monostable is triggered and the MOSFET connected to pin TACHO is turned off for a constant time tPULSE (see Figure 17). The off time tPULSE can be set using the external RC network (RPUL, CPUL) connected to the pin RCPULSE. Figure 19 gives the relation between tPULSE and CPUL, RPUL. We have approximately: tPULSE = 0.6 * RPUL * CPUL where CPUL should be chosen in the range 1nF ... 100nF and RPUL in the range 20K ... 100K. By connecting the tachometer pin to an external pull-up resistor, the output signal average value VM is proportional to the frequency of the Hall Effect signal and, therefore, to the motor speed. This realizes a simple Frequency-to-Voltage Converter. An op amp, configured as an integrator, filters the signal and compares it with a reference voltage VREF, which sets the speed of the motor. t P UL SE V M = ----------------- V DD T Figure 17. Tacho Operation Waveforms.
H1
H2
H3
VTACHO VM
t PULSE
VDD
T
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Figure 18. Tachometer Speed Control Loop.
H1
RCPULSE VDD RPUL RDD CPUL
TACHO MONOSTABLE
R3
TACHO
C1
R4 VREF R1
VREF
CREF2
R2
CREF1
Figure 19. tPULSE versus CPUL and RPUL.
1 .10
4
R PUL = 100k
1 .10 tpulse [s]
3
R PUL = 47k
R PUL = 20k
100
10 1 10 Cpul [nF] 100
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3.7 NON-DISSIPATIVE OVERCURRENT DETECTION and PROTECTION The L6229 integrates an Overcurrent Detection Circuit (OCD) for full protection. This circuit provides Output-toOutput and Output-to-Ground short circuit protection as well. With this internal over current detection, the external current sense resistor normally used and its associated power dissipation are eliminated. Figure 20 shows a simplified schematic for the overcurrent detection circuit. To implement the over current detection, a sensing element that delivers a small but precise fraction of the output current is implemented with each High Side power MOS. Since this current is a small fraction of the output current there is very little additional power dissipation. This current is compared with an internal reference current IREF. When the output current reaches the detection threshold (typically ISOVER = 2.8A) the OCD comparator signals a fault condition. When a fault condition is detected, an internal open drain MOS with a pull down capability of 4mA connected to pin DIAG is turned on. The pin DIAG can be used to signal the fault condition to a C or to shut down the Three-Phase Bridge simply by connecting it to pin EN and adding an external R-C (see REN, CEN). Figure 20. Overcurrent Protection Simplified Schematic
OUT1 VSA OUT2 OUT3 VSB
HIGH SIDE DMOS I1 POWER SENSE 1 cell TO GATE LOGIC REN CEN DIAG RDS(ON) 40 TYP. EN POWER DMOS n cells
HIGH SIDE DMOS I2 POWER DMOS n cells POWER SENSE 1 cell I3
HIGH SIDE DMOS
C or LOGIC
POWER DMOS n cells
POWER SENSE 1 cell
VDD
+
I1 / n I1+I2 / n I2/ n
OCD COMPARATOR
INTERNAL OPEN-DRAIN
IREF
OVER TEMPERATURE
I3/ n IREF
D02IN1381
Figure 21 shows the Overcurrent Detetection operation. The Disable Time tDISABLE before recovering normal operation can be easily programmed by means of the accurate thresholds of the logic inputs. It is affected whether by CEN and REN values and its magnitude is reported in Figure 22. The Delay Time tDELAY before turning off the bridge when an overcurrent has been detected depends only by CEN value. Its magnitude is reported in Figure 23 CEN is also used for providing immunity to pin EN against fast transient noises. Therefore the value of CEN should be chosen as big as possible according to the maximum tolerable Delay Time and the REN value should be chosen according to the desired Disable Time. The resistor REN should be chosen in the range from 2.2K to 180K. Recommended values for REN and CEN are respectively 100K and 5.6nF that allow obtaining 200s Disable Time.
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L6229
Figure 21. Overcurrent Protection Waveforms
IOUT ISOVER
VEN=VDIAG VDD Vth(ON) Vth(OFF) VEN(LOW)
ON OCD OFF ON BRIDGE OFF tOCD(ON) tEN(FALL) tD(OFF)EN tOCD(OFF) tEN(RISE) tD(ON)EN
D02IN1383
tDELAY
tDISABLE
Figure 22. tDISABLE versus CEN and REN.
3 1 .1 0
R EN = 220 k
R EN = 100 k
R EN = 47 k R EN = 33 k R EN = 10 k
tDISABLE [s]
1 00
10
1
1
10
1 00
C E N [n F ]
Figure 23. tDELAY versus CEN.
10
tdelay [s]
1
0.1
1
10 Cen [nF]
100
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4
APPLICATION INFORMATION
A typical application using L6229 is shown in Figure 24. Typical component values for the application are shown in Table 9. A high quality ceramic capacitor (C2) in the range of 100nF to 200nF should be placed between the power pins VSA and VSB and ground near the L6229 to improve the high frequency filtering on the power supply and reduce high frequency transients generated by the switching. The capacitor (CEN) connected from the EN input to ground sets the shut down time when an over current is detected (see Overcurrent Protection). The two current sensing inputs (SENSEA and SENSEB) should be connected to the sensing resistor RSENSE with a trace length as short as possible in the layout. The sense resistor should be non-inductive resistor to minimize the di/ dt transients across the resistor. To increase noise immunity, unused logic pins are best connected to 5V (High Logic Level) or GND (Low Logic Level) (see pin description). It is recommended to keep Power Ground and Signal Ground separated on PCB. Table 9. Component Values for Typical Application.
C1 C2 C3 CBOOT COFF CPUL CREF1 CREF2 CEN CP D1 D2 100F 100nF 220nF 220nF 1nF 10nF 33nF 100nF 5.6nF 10nF 1N4148 1N4148 R1 R2 R3 R4 RDD REN RP RSENSE ROFF RPUL RH1, RH2, RH3 5K6 1K8 4K7 1M 1K 100K 100 0.6 33K 47K 10K
Figure 24. Typical Application
+ VS 8-52VDC C1 C2 D1 D2 CBOOT SIGNAL GROUND RSENSE VBOOT SENSEA SENSEB OUT1 HALL SENSOR +5V RH1 RH2 RH3 M OUT2 OUT3 H1 H2 H3 15 3 10 5 21 16 1 23 24 18 19 6 7
D02IN1357
VSA VSB RP CP VCP
20 17
13
VREF CREF1
R1 R2
+ C3
VREF CREF2
POWER GROUND -
22 2 12
DIAG R4 EN REN ENABLE CEN R3 FWD/REV BRAKE
11 14
THREE-PHASE MOTOR
FWD/REV BRAKE
8
TACHO
COFF
RDD 5V
4
RCOFF
ROFF CPUL
9
RCPULSE RPUL
GND
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L6229
4.1 OUTPUT CURRENT CAPABILITY AND IC POWER DISSIPATION In Figure 25 is shown the approximate relation between the output current and the IC power dissipation using PWM current control. For a given output current the power dissipated by the IC can be easily evaluated, in order to establish which package should be used and how large must be the on-board copper dissipating area to guarantee a safe operating junction temperature (125C maximum). Figure 25. IC Power Dissipation versus Output Power.
I1
IOUT
10 8
I2
IOUT
PD [W]
6 4 2 0
I3
IOUT
Test Condition s: Supply Voltage = 24 V
0 0.25 0.5 0.75 1 1.25 1.5
No PWM
fSW = 30 kHz (slow decay)
IOUT [A]
4.2 THERMAL MANAGEMENT In most applications the power dissipation in the IC is the main factor that sets the maximum current that can be delivered by the device in a safe operating condition. Selecting the appropriate package and heatsinking configuration for the application is required to maintain the IC within the allowed operating temperature range for the application. Figures 26, 27 and 28 show the Junction-to-Ambient Thermal Resistance values for the PowerSO36, PowerDIP24 and SO24 packages. For instance, using a PowerSO package with copper slug soldered on a 1.5mm copper thickness FR4 board with 6cm2 dissipating footprint (copper thickness of 35m), the Rth(j-amb) is about 35C/W. Figure 29 shows mounting methods for this package. Using a multi-layer board with vias to a ground plane, thermal impedance can be reduced down to 15C/W. Figure 26. PowerSO36 Junction-Ambient thermal resistance versus on-board copper area.
C / W
43
38
33
W ith o ut G ro u nd La yer
28
W ith Gro un d La yer W ith Gro un d La yer+ 16 via H o le s
23
18
On-Board Copper Area
13 1 2 3 4 5 6 7 8 9 10 11 12 13
s q. cm
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L6229
Figure 27. PowerDIP24 Junction-Ambient thermal resistance versus on-board copper area.
C / W
49 48 47 46 45 44 43 42 41 40 39 1 2 3 4 5 6 7 8 9 10 11 12
s q . cm
C o p pe r Are a is o n To p S i de C o p pe r Are a is o n Bo tto m S id e
On-Board Copper Area
Figure 28. SO24 Junction-Ambient thermal resistance versus on-board copper area.
C / W 68 66 64 62 60 58 56 54 52 50 48 1 2 3 4 5 6 7 8 9 10 11 12 s q. cm
C o pp er A re a is o n T op S id e
On-Board Copper Area
Figure 29. Mounting the PowerSO Package.
Slug soldered to PCB with dissipating area
Slug soldered to PCB with dissipating area plus ground layer
Slug soldered to PCB with dissipating area plus ground layer contacted through via holes
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L6229
Figure 30. PowerSO36 Mechanical Data & Package Dimensions
DIM. A A2 A4 A5 a1 b c D D1 D2 E E1 E2 E3 E4 e e3 G H h L N s mm TYP. inch TYP.
MIN. 3.25 0.8
MAX. 3.5 3.3 1 0.075 0.38 0.32 16 9.8
MIN. 0.128 0.031
MAX. 0.138 0.13 0.039 0.003 0.015 0.012 0.630 0.38
OUTLINE AND MECHANICAL DATA
0.2 0 0.22 0.23 15.8 9.4 1 13.9 10.9 5.8 2.9 0.65 11.05 0 15.5 0.8 0.075 0 15.9 0.61 1.1 1.1 0.031 10 (max) 8 (max) 14.5 11.1 2.9 6.2 3.2 0.547 0.429 0.228 0.114 0 0.008 0.009 0.622 0.37
0.008
0.039 0.57 0.437 0.114 0.244 1.259 0.026 0.435 0.003 0.625 0.043 0.043
PowerSO36
Note: "D and E1" do not include mold flash or protusions. - Mold flash or protusions shall not exceed 0.15mm (0.006") - Critical dimensions are "a3", "E" and "G".
N
N a2 A DETAIL A e3 H lead e A a1 E DETAIL A
c DETAIL B
D a3
36 19
slug BOTTOM VIEW E3
B E2 E1 DETAIL B
0.35 Gage Plane
D1
1
1
8
-C-
S h x 45 b
0.12
M
L
SEATING PLANE G C
AB
PSO36MEC
(COPLANARITY)
0096119 B
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L6229
Figure 31. PDIP-24 Mechanical Data & Package Dimensions
mm MIN. A A1 A2 B B1 c D E e E1 e1 L M 3.180 6.350 0.410 1.400 0.200 31.62 7.620 2.54 6.600 7.620 3.430 0.125 6.860 0.250 0.380 3.300 0.460 1.520 0.250 31.75 0.510 1.650 0.300 31.88 8.260 0.016 0.055 0.008 1.245 0.300 0.100 0.260 0.300 0.270 TYP. MAX. 4.320 0.015 0.130 0.018 0.060 0.010 1.250 0.020 0.065 0.012 1.255 0.325 MIN. inch TYP. MAX. 0.170
DIM.
OUTLINE AND MECHANICAL DATA
0.135
PDIP 24 (0.300")
0 min, 15 max.
E1
A2
A
L
A1
B
B1
e
e1
D
24
13 c
1
12 M
SDIP24L
0034965 D
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L6229
Figure 32. SO24 Mechanical Data & Package Dimensions
mm DIM. MIN. A A1 B C D (1) E e H h L k ddd 10.0 0.25 0.40 2.35 0.10 0.33 0.23 15.20 7.40 1.27 10.65 0.75 1.27 0.394 0.010 0.016 TYP. MAX. 2.65 0.30 0.51 0.32 15.60 7.60 MIN. 0.093 0.004 0.013 0.009 0.598 0.291 0.050 0.419 0.030 0.050 TYP. MAX. 0.104 0.012 0.200 0.013 0.614 0.299 Weight: 0.60gr inch
OUTLINE AND MECHANICAL DATA
0 (min.), 8 (max.) 0.10 0.004
(1) "D" dimension does not include mold flash, protusions or gate burrs. Mold flash, protusions or gate burrs shall not exceed 0.15mm per side.
SO24
0070769 C
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L6229
Table 10. Revision History
Date September 2003 January 2004 October 2004 Revision 1 2 3 First Issue Migration from ST-Press dms to EDOCS. Updated the style graphic form. Description of Changes
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L6229
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. Specifications 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. All other names are the property of their respective owners (c) 2004 STMicroelectronics - All rights reserved STMicroelectronics group of companies Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America www.st.com
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