L6208 DMOS DRIVER FOR BIPOLAR STEPPER MOTOR ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ OPERATING SUPPLY VOLTAGE FROM 8 TO 52V 5.6A OUTPUT PEAK CURRENT (2.8A RMS) RDS(ON) 0.3Ω TYP.
L6208 ABSOLUTE MAXIMUM RATINGS Symbol VS VOD VBOOT Parameter Test conditions Value Unit Supply Voltage VSA = VSB = VS 60 V Differential Voltage between VSA, OUT1A, OUT2A, SENSEA and VSB, OUT1B, OUT2B, SENSEB VSA = VSB = VS = 60V; VSENSEA = VSENSEB = GND 60 V Bootstrap Peak Voltage VSA = VSB = VS VS + 10 V VIN,VEN Input and Enable Voltage Range -0.3 to +7 V VREFA, VREFB Voltage Range at pins VREFA and VREFB -0.3 to +7 V -0.
L6208 THERMAL DATA Symbol Description Rth-j-pins Maximum Thermal Resistance Junction-Pins Rth-j-case Maximum Thermal Resistance Junction-Case PowerDIP24 SO24 PowerSO36 Unit 18 14 - °C/W - - 1 °C/W 43 51 - °C/W Rth-j-amb1 Maximum Thermal Resistance Junction-Ambient Rth-j-amb1 Maximum Thermal Resistance Junction-Ambient (2) - - 35 °C/W Rth-j-amb1 Maximum Thermal Resistance Junction-Ambient (3) - - 15 °C/W Rth-j-amb2 Maximum Thermal Resistance Junction-Ambient (4) 58 77
L6208 PIN DESCRIPTION PACKAGE SO24/ PowerDIP24 PowerSO36 PIN # PIN # 1 Name Type 10 CLOCK Logic Input Step Clock input. The state machine makes one step on each rising edge. 2 11 CW/CCW Logic Input Selects the direction of the rotation. HIGH logic level sets clockwise direction, whereas LOW logic level sets counterclockwise direction. If not used, it has to be connected to GND or +5V. 3 12 SENSEA Power Supply Bridge A Source Pin.
L6208 PIN DESCRIPTION (continued) PACKAGE SO24/ PowerDIP24 PowerSO36 PIN # PIN # 21 (6) Name Type Function 5 OUT2A Power Output 22 7 VCP Output 23 8 RESET Logic Input 24 9 VREFA Analog Input Bridge A Output 2. Charge Pump Oscillator Output. Reset Pin. LOW logic level restores the Home State (State 1) on the Phase Sequence Generator State Machine. If not used, it has to be connected to +5V. Bridge A Current Controller Reference Voltage. Do not leave this pin open or connected to GND.
L6208 ELECTRICAL CHARACTERISTICS (continued) (Tamb = 25°C, Vs = 48V, unless otherwise specified) Symbol Parameter Test Conditions IIL Low Level Logic Input Current GND Logic Input Voltage IIH High Level Logic Input Current 7V Logic Input Voltage Vth(ON) Turn-on Input Threshold Vth(OFF) Turn-off Input Threshold Vth(HYS) Input Threshold Hysteresis Min Typ Max -10 Unit µA 1.8 10 µA 2.0 V 0.8 1.3 V 0.25 0.
L6208 ELECTRICAL CHARACTERISTICS (continued) (Tamb = 25°C, Vs = 48V, unless otherwise specified) Symbol tOFF IBIAS Parameter Test Conditions PWM Recirculation Time Min Typ Max Unit ROFF = 20KΩ; COFF = 1nF 13 µs ROFF = 100KΩ; COFF = 1nF 61 µs Input Bias Current at pins VREFA and VREFB 10 µA 5.6 7.
L6208 Figure 2. Clock to Output Delay Time CLOCK Vth(ON) t IOUT t D01IN1317 tDCLK Figure 3. Minimum Timing Definition; Clock Input CLOCK Vth(ON) Vth(OFF) tCLK(MIN)L Vth(OFF) tCLK(MIN)H D01IN1318 Figure 4.
L6208 Figure 5. Overcurrent Detection Timing Definition IOUT ISOVER ON BRIDGE OFF VEN 90% 10% tOCD(ON) tOCD(OFF) D02IN1399 CIRCUIT DESCRIPTION POWER STAGES and CHARGE PUMP The L6208 integrates two independent Power MOS Full Bridges. 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 Phase Sequence Generator (see below).
L6208 Figure 6. Charge Pump Circuit VS CBOOT D1 D2 RP CP VCP VBOOT VSA VSB D01IN1328 LOGIC INPUTS Pins CONTROL, HALF/FULL, CLOCK, RESET and CW/CCW are TTL/CMOS and uC compatible logic inputs. The internal structure is shown in Fig. 7. Typical value for turn-on and turn-off thresholds are respectively Vth(ON)= 1.8V and Vth(OFF)= 1.3V. Pin EN (Enable) has identical input structure with the exception that the drain of the Overcurrent and thermal protection MOSFET is also connected to this pin.
L6208 PWM CURRENT CONTROL The L6208 includes a constant off time PWM current controller for each of the two bridges. The current control circuit senses the bridge current by sensing the voltage drop across an external sense resistor connected between the source of the two lower power MOS transistors and ground, as shown in Figure 10. As the current in the motor builds up the voltage across the sense resistor increases proportionally.
L6208 Figure 11. Output Current Regulation Waveforms IOUT VREF RSENSE tOFF tON tOFF 1µs tBLANK 1µs tBLANK VSENSE VREF Slow Decay 0 Slow Decay ay ay c Fast De c Fast De tRCRISE VRC tRCRISE 5V 2.5V tRCFALL tRCFALL 1µs tDT 1µs tDT ON OFF SYNCHRONOUS OR QUASI SYNCHRONOUS RECTIFICATION D01IN1334 B C D A B C D 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.
L6208 t O N > t O N ( MIN ) = 1.5µ s (typ. value) t O N > t RCRISE – t DT 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.
L6208 DECAY MODES The CONTROL input is used to select the behavior of the bridge during the off time. When the CONTROL pin is low, the Fast Decay mode is selected and both transistors in the bridge are switched off during the off time. When the CONTROL pin is high, the Slow Decay mode is selected and only the low side transistor of the bridge is switched off during the off time. Figure 14 shows the operation of the bridge in the Fast Decay mode.
L6208 time. The drive mode is selected by the HALF/FULL input and the current state of the sequence generator as described below. A rising edge of the CLOCK input advances the state machine to the next state. The direction of rotation is set by the CW/CCW input. The RESET input resets the state machine to state. HALF STEP MODE A HIGH logic level on the HALF/FULL input selects Half Step Mode. Figure 16 shows the motor current waveforms and the state diagram for the Phase Sequencer Generator.
L6208 Figure 18. Wave Drive Mode IOUTA 3 4 5 IOUTB 6 2 1 7 8 CLOCK Start Up or Reset 2 4 6 8 2 4 6 8 D01IN1321 NON-DISSIPATIVE OVERCURRENT PROTECTION The L6208 integrates an Overcurrent Detection Circuit (OCD). This circuit provides protection against a short circuit to ground or between two phases of the bridge. With this internal over current detection, the external current sense resistor normally used and its associated power dissipation are eliminated.
L6208 Figure 20 shows the Overcurrent Detection 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 21. 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 22.
L6208 Figure 21. tDISABLE versus C EN and REN (VDD = 5V). R EN = 220 kΩ 3 1 . 10 R EN = 100 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 1 00 C E N [n F ] Figure 22. tDELAY versus CEN (VDD = 5V). tdelay [µs] 10 1 0.1 1 10 Cen [nF] 100 THERMAL PROTECTION In addition to the Ovecurrent Protection, the L6208 integrates a Thermal Protection for preventing the device destruction in case of junction over temperature.
L6208 APPLICATION INFORMATION A typical Bipolar Stepper Motor Driver application using L6208 is shown in Fig. 23. Typical component values for the application are shown in Table 2. A high quality ceramic capacitor in the range of 100 to 200 nF should be placed between the power pins (VSA and VSB) and ground near the L6208 to improve the high frequency filtering on the power supply and reduce high frequency transients generated by the switching.
L6208 Output Current Capability and IC Power Dissipation In Fig. 24, 25, 26 and 27 are shown the approximate relation between the output current and the IC power dissipation using PWM current control driving a two-phase stepper motor, for different driving sequences: – HALF STEP mode (Fig. 24) in which alternately one phase / two phases are energized. – NORMAL DRIVE (FULL-STEP TWO PHASE ON) mode (Fig. 25) in which two phases are energized during each step. – WAVE DRIVE (FULL-STEP ONE PHASE ON) mode (Fig.
L6208 Figure 26. IC Power Dissipation versus Output Current in WAVE Mode (full step one phase on). WAVE DRIVE IA 10 8 I OUT IB 6 PD [W] I OUT 4 Test Conditions: Supply Voltage = 24V 2 0 0 0.5 1 1.5 2 2.5 No PW M fSW = 3 0 kHz (slow decay) 3 I OUT [A] Figure 27. IC Power Dissipation versus Output Current in MICROSTEPPING Mode. MICROSTEPPING IA 10 I OUT 8 I OUT 6 IB PD [W] 4 2 0 0 0.5 1 1.5 I OUT [A] 2 2.
L6208 Figure 28. PowerSO36 Junction-Ambient Thermal Resistance versus On-Board Copper Area. ºC / 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 On-Board Copper Area 18 13 1 2 3 4 5 6 7 8 9 10 11 12 13 s q. cm Figure 29. PowerDIP24 Junction-Ambient Thermal Resistance versus On-Board Copper Area.
L6208 Figure 32. Typical Quiescent Current vs. Supply Voltage Figure 35. Typical High-Side RDS(ON) vs. Supply Voltage Iq [m A] RDS(ON) [Ω] 5.6 fsw = 1kHz 0.380 Tj = 25°C 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 0 60 5 10 15 20 25 30 VS [V] Figure 33. Normalized Typical Quiescent Current vs. Switching Frequency Figure 36. Normalized RDS(ON) vs.
L6208 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.
L6208 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.
L6208 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.
L6208 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.
