L6235 DMOS DRIVER FOR THREE-PHASE BRUSHLESS DC MOTOR ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ OPERATING SUPPLY VOLTAGE FROM 8 TO 52V 5.6A OUTPUT PEAK CURRENT (2.8A DC) RDS(ON) 0.3Ω 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.
L6235 ABSOLUTE MAXIMUM RATINGS Symbol VS VOD VBOOT Parameter Test conditions Value Unit Supply Voltage VSA = VSB = VS 60 V Differential Voltage between: VSA, OUT1, OUT2, SENSEA and VSB, OUT3, SENSEB VSA = VSB = VS = 60V; VSENSEA = VSENSEB = GND 60 V Bootstrap Peak Voltage VSA = VSB = VS VS + 10 V VIN, VEN Logic Inputs Voltage Range -0.3 to 7 V VREF Voltage Range at pin VREF -0.3 to 7 V Voltage Range at pin RCOFF -0.3 to 7 V VRCPULSE Voltage Range at pin RCPULSE -0.
L6235 THERMAL DATA Symbol Description PDIP24 SO24 18 14 Rth(j-pins) Maximum Thermal Resistance Junction-Pins Rth(j-case) Maximum Thermal Resistance Junction-Case Rth(j-amb)1 MaximumThermal Resistance Junction-Ambient (1) 43 Rth(j-amb)1 Maximum Thermal Resistance Junction-Ambient (2) Rth(j-amb)1 Rth(j-amb)2 PowerSO36 Unit °C/W 1 °C/W 51 - °C/W - - 35 °C/W MaximumThermal Resistance Junction-Ambient (3) - - 15 °C/W Maximum Thermal Resistance Junction-Ambient (4) 58 77 62 °C/
L6235 PIN DESCRIPTION PACKAGE SO24/ PowerDIP24 PowerSO36 PIN # PIN # 1 2 4/25 Name Type Function 10 H1 Sensor Input Single Ended Hall Effect Sensor Input 1. 11 DIAG Open Drain Output 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. 3 12 SENSEA 4 13 RCOFF RC Pin 5 15 OUT1 Power Output 6, 7, 18, 19 1, 18, 19, 36 GND GND Ground terminals.
L6235 PIN DESCRIPTION (continued) PACKAGE SO24/ PowerDIP24 PowerSO36 PIN # PIN # 20 4 VSA 21 5 OUT2 22 7 VCP Output 23 8 H2 Sensor Input Single Ended Hall Effect Sensor Input 2. 24 9 H3 Sensor Input Single Ended Hall Effect Sensor Input 3. Name Type Function 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 2. Charge Pump Oscillator Output.
L6235 ELECTRICAL CHARACTERISTICS (continued) (VS = 48V , Tamb = 25 °C , unless otherwise specified) Symbol Parameter Test Conditions Min Typ Max Unit Switching Characteristics tD(on)EN Enable to out turn-ON delay time (7) ILOAD = 2.8 A, Resistive Load 110 250 400 ns tD(off)EN Enable to out turn-OFF delay time (7) ILOAD = 2.8 A, Resistive Load 300 550 800 ns tD(on)IN Other Logic Inputs to Output TurnON delay Time ILOAD = 2.
L6235 Figure 1. Switching Characteristic Definition EN Vth(ON) Vth(OFF) t IOUT 90% 10% t D01IN1316 tRISE tFALL tD(OFF)EN tD(ON)EN Figure 2.
L6235 CIRCUIT DESCRIPTION POWER STAGES and CHARGE PUMP LOGIC INPUTS The L6235 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) = 0.3Ω (typical value @25°C) with intrinsic fast freewheeling diode. Switching patterns are generated by the PWM Current Controller and the Hall Effect Sensor Decoding Logic (see relative paragraphs).
L6235 PWM CURRENT CONTROL The L6235 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 7. As the current in the motor increases the voltage across the sense resistor increases proportionally.
L6235 Figure 8. Output Current Regulation Waveforms IOUT VREF RSENSE tON tOFF tOFF 1µs tBLANK 1µs tBLANK VSENSE VREF Slow Decay 0 Slow Decay tRCRISE VRC tRCRISE 5V 2.5V tRCFALL tRCFALL 1µs tDT 1µs tDT ON OFF SYNCHRONOUS RECTIFICATION D02IN1351 B C D A B C D Figure 9 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.
L6235 Figure 10 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.
L6235 SLOW DECAY MODE Figure 11 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.
L6235 Table 2. 60 and 120 Electrical Degree Decoding Logic in Forward Direction. Hall 120° 1 2 3a - 4 5 6a - Hall 60° 1 2 - 3b 4 5 - 6b H1 H H L H L L H L H2 L H H H H L L L H3 L L L H H H H L OUT1 Vs High Z GND GND GND High Z Vs Vs OUT2 High Z Vs Vs Vs High Z GND GND GND OUT3 GND GND High Z High Z Vs Vs High Z High Z Phasing 1->3 2->3 2->1 2->1 3->1 3->2 1->2 1->2 Figure 12. 120° Hall Sensor Sequence.
L6235 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 14. For component values refer to Application Information section. The monostable output drives an open drain output pin (TACHO).
L6235 Figure 15. Tachometer Speed Control Loop. H1 RCPULSE TACHO MONOSTABLE VDD CPUL RPUL R3 RDD TACHO C1 R4 VREF R1 VREF CREF2 CREF1 R2 Figure 16. tPULSE versus C PUL and RPUL. 4 1 .10 R PUL = 100kΩ R PUL = 47kΩ 3 1 .
L6235 NON-DISSIPATIVE OVERCURRENT DETECTION and PROTECTION The L6235 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 17 shows a simplified schematic for the overcurrent detection circuit.
L6235 Figure 18. Overcurrent Protection Waveforms IOUT ISOVER VEN=VDIAG VDD Vth(ON) Vth(OFF) VEN(LOW) ON OCD OFF ON tDELAY BRIDGE tDISABLE OFF tOCD(ON) tEN(FALL) tOCD(OFF) tEN(RISE) tD(ON)EN tD(OFF)EN D02IN1383 Figure 19. tDISABLE versus C EN and REN. R EN = 22 0 k Ω 3 1 .1 0 R EN = 10 0 k Ω R EN = 4 7 k Ω R EN = 3 3 k Ω tDISABLE [µs] R EN = 1 0 k Ω 100 10 1 1 10 100 C E N [n F ] Figure 20. tDELAY versus CEN. tdelay [µs] 10 1 0.
L6235 APPLICATION INFORMATION A typical application using L6235 is shown in Figure 21. Typical component values for the application are shown in Table 3. 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 L6235 to improve the high frequency filtering on the power supply and reduce high frequency transients generated by the switching.
L6235 OUTPUT CURRENT CAPABILITY AND IC POWER DISSIPATION In Figure 22 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 (125°C maximum). Figure 22. IC Power Dissipation versus Output Power.
L6235 Figure 24. PowerDIP24 Junction-Ambient thermal resistance versus on-board copper area. ºC / W On-Board Copper Area 49 48 C o p pe r Are a is o n Bo tto m S id e 47 C o p pe r Are a is o n To p S i de 46 45 44 43 42 41 40 39 1 2 3 4 5 6 7 8 9 10 11 12 s q . cm Figure 25. SO24 Junction-Ambient thermal resistance versus on-board copper area. On-Board Copper Area ºC / W 68 66 64 62 60 C o pp er A re a is o n T op S id e 58 56 54 52 50 48 1 2 3 4 5 6 7 8 9 10 11 12 s q.
L6235 Figure 27. Typical Quiescent Current vs. Supply Voltage Figure 30. Typical High-Side RDS(ON) vs. Supply Voltage Iq [m A] RDS(ON) [Ω] 5.6 fsw = 1kHz Tj = 25°C 0.380 0.376 Tj = 85°C 5.4 0.372 Tj = 25°C 0.368 Tj = 125°C 0.364 5.2 0.360 0.356 5.0 0.352 0.348 4.8 0.344 0.340 0.336 4.6 0 10 20 30 V S [V] 40 50 60 0 5 10 15 20 25 30 VS [V] Figure 28. Normalized Typical Quiescent Current vs. Switching Frequency Figure 31. Normalized RDS(ON) vs.
L6235 DIM. A a1 a2 a3 b c D (1) D1 E e e3 E1 (1) E2 E3 E4 G H h L N S MIN. mm TYP. 0.10 0 0.22 0.23 15.80 9.40 13.90 MAX. 3.60 0.30 3.30 0.10 0.38 0.32 16.00 9.80 14.50 inch TYP. MIN. 0.004 0 0.008 0.009 0.622 0.370 0.547 0.65 11.05 10.90 0.0256 0.435 11.10 0.429 2.90 6.20 0.228 3.20 0.114 0.10 0 15.90 0.610 1.10 1.10 0.031 10°(max.) 8 °(max.) 5.80 2.90 0 15.50 0.80 OUTLINE AND MECHANICAL DATA MAX. 0.141 0.012 0.130 0.004 0.015 0.012 0.630 0.385 0.570 0.437 0.114 0.244 0.126 0.004 0.626 0.
L6235 mm DIM. MIN. TYP. A A1 inch MAX. MIN. TYP. 4.320 0.380 A2 0.170 0.015 3.300 0.130 B 0.410 0.460 0.510 0.016 0.018 0.020 B1 1.400 1.520 1.650 0.055 0.060 0.065 c 0.200 0.250 0.300 0.008 0.010 0.012 D 31.62 31.75 31.88 1.245 1.250 1.255 E 7.620 8.260 0.300 e 2.54 E1 6.350 e1 L 6.600 M 0.325 0.100 6.860 0.250 0.260 0.270 0.300 7.620 3.180 OUTLINE AND MECHANICAL DATA MAX. 3.430 0.125 0.135 Powerdip 24 0˚ min, 15˚ max.
L6235 mm inch DIM. MIN. TYP. MAX. MIN. TYP. MAX. A 2.35 2.65 0.093 0.104 A1 0.10 0.30 0.004 0.012 B 0.33 0.51 0.013 0.200 C 0.23 0.32 0.009 0.013 D (1) 15.20 15.60 0.598 0.614 E 7.40 7.60 0.291 0.299 e 1.27 10.0 10.65 0.394 0.419 h 0.25 0;75 0.010 0.030 L 0.40 1.27 0.016 0.050 ddd Weight: 0.60gr 0.050 H k OUTLINE AND MECHANICAL DATA 0˚ (min.), 8˚ (max.) 0.10 0.004 (1) “D” dimension does not include mold flash, protusions or gate burrs.
L6235 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.
