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DRV8886PWPR

DRV8886PWPR

  • 厂商:

    BURR-BROWN(德州仪器)

  • 封装:

    HTSSOP24_EP

  • 描述:

    IC MTR DRV BIPOLR 8-37V 24HTSSOP

  • 数据手册
  • 价格&库存
DRV8886PWPR 数据手册
Product Folder Order Now Support & Community Tools & Software Technical Documents DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 DRV8886 2-A Stepper Motor Driver With Integrated Current Sense 1 Features 3 Description • The DRV8886 is a stepper motor driver for industrial and consumer end equipment applications. The device is fully integrated with two N-channel power MOSFET H-bridge drivers, a microstepping indexer, and integrated current sensing. The DRV8886 is capable of driving up to 2-A full scale or 1.4-A rms output current (24-V and TA = 25°C, dependent on PCB design). • • • • • • • • • • PWM microstepping stepper motor driver – Up to 1/16 microstepping – Non-circular and standard ½ step modes Integrated current sense functionality – No sense resistors required – ±6.25% Full-scale current accuracy Slow and mixed decay options 8 to 37-V Operating supply voltage range Low RDS(ON): 550 mΩ HS + LS at 24 V, 25°C High current capacity – 3-A Peak per bridge – 2-A Full-scale per bridge – 1.4-A rms per bridge Fixed off-time PWM current regulation Simple STEP/DIR interface Low-current sleep mode (20 μA) Small package and footprint – 24 HTSSOP PowerPAD™ package – 28 WQFN package Protection features – VM Undervoltage lockout (UVLO) – Charge pump undervoltage (CPUV) – Overcurrent protection (OCP) – Thermal shutdown (TSD) – Fault condition indication pin (nFAULT) 2 Applications Device protection features are provided for supply undervoltage, charge pump faults, overcurrent, short circuits, and overtemperature. Fault conditions are indicated by the nFAULT pin. Device Information PART NUMBER DRV8886 PACKAGE (1) BODY SIZE (NOM) HTSSOP (24) 7.80 mm × 4.40 mm WQFN (28) 5.50 mm × 3.5 mm (1) For all available packages, see the orderable addendum at the end of the data sheet. Simplified Schematic 8 to 37 V DRV8886 STEP DIR M 2A ± Bipolar stepper motors Multi-function printers and scanners Laser beam printers 3D printers Automatic teller and money handling machines Video security cameras Office automation machines Factory automation and robotics A simple STEP/DIR interface allows an external controller to manage the direction and step rate of the stepper motor. The device can be configured in different step modes ranging from full-step to 1/16 microstepping. A low-power sleep mode is provided for very low standby quiescent standby current using a dedicated nSLEEP pin. + • • • • • • • • The DRV8886 uses an internal current sense architecture to eliminate the need for two external power sense resistors, saving PCB area and system cost. The DRV8886 uses an internal fixed off-time PWM current regulation scheme adjustable between slow and mixed decay options. Controller 1 Step Size Decay Mode nFAULT Stepper Motor Driver Current Sense + ± 2A 1/16 µstep Copyright © 2017, Texas Instruments Incorporated 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 4 6.1 6.2 6.3 6.4 6.5 6.6 6.7 4 4 5 5 6 8 9 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics........................................... Indexer Timing Requirements................................... Typical Characteristics .............................................. Detailed Description ............................................ 11 7.1 Overview ................................................................. 11 7.2 Functional Block Diagram ....................................... 12 7.3 Feature Description................................................. 13 7.4 Device Functional Modes........................................ 32 8 Application and Implementation ........................ 33 8.1 Application Information............................................ 33 8.2 Typical Application .................................................. 33 9 Power Supply Recommendations...................... 36 9.1 Bulk Capacitance ................................................... 36 10 Layout................................................................... 37 10.1 Layout Guidelines ................................................. 37 10.2 Layout Example .................................................... 37 11 Device and Documentation Support ................. 38 11.1 11.2 11.3 11.4 11.5 11.6 Documentation Support ........................................ Receiving Notification of Documentation Updates Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 38 38 38 38 38 38 12 Mechanical, Packaging, and Orderable Information ........................................................... 38 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision B (November 2018) to Revision C • Added Various Sources of Error and Application-Specific Error Calculations sections. ...................................................... 18 Changes from Revision A (July 2018) to Revision B • Page Page Changed device status from Advanced Information to Production Data................................................................................ 1 Changes from Original (January 2017) to Revision A Page • Added the WQFN package option.......................................................................................................................................... 1 • Changed the units of the High-Side and Low-Side RDS(ON) axis labels from mΩ to Ω in the high-side and low-side RDS(ON) over VM and over temperature graphs ...................................................................................................................... 9 2 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 5 Pin Configuration and Functions PWP PowerPAD™ Package 24-Pin HTSSOP Top View 22 M1 VM 4 21 M0 AOUT1 5 20 DIR PGND 6 19 STEP 18 ENABLE Thermal AOUT2 7 Pad BOUT2 8 17 nSLEEP PGND 9 16 RREF BOUT1 10 15 nFAULT VM 11 14 DVDD GND 12 13 AVDD DECAY 3 25 VCP VCP 1 24 TRQ VM 2 23 M1 AOUT1 3 22 M0 PGND 4 21 DIR AOUT2 5 20 STEP Thermal Pad BOUT2 6 19 ENABLE PGND 7 18 nSLEEP BOUT1 8 17 RREF VM 9 16 nFAULT 10 15 NC 11 GND 14 TRQ NC 23 CPL 2 26 CPH 27 DECAY 13 24 12 1 CPH CPL 28 RHR Package 28-Pin WQFN With Exposed Thermal Pad Top View NC AVDD DVDD NC Not to scale Not to scale Pin Functions PIN NAME TYPE (1) NO. HTSSOP WQFN AOUT1 5 3 AOUT2 7 5 AVDD 13 12 BOUT1 10 8 BOUT2 8 6 CPH 2 28 CPL 1 27 DECAY 24 25 DIR 20 DVDD 14 ENABLE O PWR O DESCRIPTION Winding A output. Connect to stepper motor winding. Internal regulator. Bypass to GND with a X5R or X7R, 0.47-μF, 6.3-V ceramic capacitor. Winding B output. Connect to stepper motor winding. PWR Charge pump switching node. Connect a X5R or X7R, 0.022-μF, VM-rated ceramic capacitor from CPH to CPL. I Decay-mode setting. Sets the decay mode (see the Decay Modes section). Decay mode can be adjusted during operation. 21 I Direction input. Logic level sets the direction of stepping; internal pulldown resistor. 13 PWR 18 19 I GND 12 10 PWR M0 21 22 M1 22 23 I Internal regulator. Bypass to GND with a X5R or X7R, 0.47-μF, 6.3-V ceramic capacitor. Enable driver input. Logic high to enable device outputs; logic low to disable; internal pulldown resistor. Device ground. Connect to system ground. Microstepping mode-setting. Sets the step mode; tri-level pins; sets the step mode; internal pulldown resistor. 11 NC — 14 15 — No connect. No internal connection 26 PGND RREF (1) 6 4 9 7 16 17 PWR I Power ground. Connect to system ground. Current-limit analog input. Connect a resistor to ground to set full-scale regulation current. I = input, O = output, PWR = power, OD = open-drain Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 3 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com Pin Functions (continued) PIN NAME TYPE (1) NO. DESCRIPTION HTSSOP WQFN STEP 19 20 I Step input. A rising edge causes the indexer to advance one step; internal pulldown resistor. TRQ 23 24 I Current-scaling control. Scales the output current; tri-level pin. VCP 3 1 PWR Charge pump output. Connect a X5R or X7R, 0.22-μF, 16-V ceramic capacitor to VM. 4 2 11 9 PWR Power supply. Connect to motor supply voltage and bypass to GND with two 0.01-μF ceramic capacitors (one for each pin) plus a bulk capacitor rated for VM. nFAULT 15 16 OD Fault indication. Pulled logic low with fault condition; open-drain output requires an external pullup resistor. nSLEEP 17 18 I Sleep mode input. Logic high to enable device; logic low to enter low-power sleep mode; internal pulldown resistor. VM 6 Specifications 6.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) (1) Power supply voltage (VM) Power supply voltage ramp rate (VM) MIN MAX UNIT –0.3 40 V 0 2 V/µs Charge pump voltage (VCP, CPH) –0.3 VM + 7 V Charge pump negative switching pin (CPL) –0.3 VM V Internal regulator voltage (DVDD) –0.3 3.8 V Internal regulator current output (DVDD) 0 1 mA Internal regulator voltage (AVDD) –0.3 5.7 V Control pin voltage (STEP, DIR, ENABLE, nFAULT, M0, M1, DECAY, TRQ, nSLEEP) –0.3 5.7 V Open drain output current (nFAULT) 0 10 mA Current limit input pin voltage (RREF) –0.3 6.0 V Continuous phase node pin voltage (AOUT1, AOUT2, BOUT1, BOUT2) –1.0 VM + 1.0 V Transient 100 ns phase node pin voltage (AOUT1, AOUT2, BOUT1, BOUT2) –3.0 VM + 3.0 V 0 3 A Operating junction temperature, TJ –40 150 °C Storage temperature, Tstg –65 150 °C Peak drive current (AOUT1, AOUT2, BOUT1, BOUT2) (1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 6.2 ESD Ratings VALUE V(ESD) (1) (2) 4 Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) ±2000 Charged-device model (CDM), per JEDEC specification JESD22-C101 (2) ±500 UNIT V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 6.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) MIN MAX UNIT VVM Power supply voltage (VM) 8 37 V VI Input voltage (DECAY, DIR, ENABLE, M0, M1, nSLEEP, STEP, TRQ) 0 5.3 V ƒPWM Applied STEP signal (STEP) 0 100 (1) kHz (2) mA IDVDD External load current (DVDD) 0 1 IFS Motor full-scale current (xOUTx) 0 2 (2) A Irms Motor RMS current (xOUTx) 0 1.4 (2) A TA Operating ambient temperature –40 125 °C (1) (2) STEP input can operate up to 500 kHz, but system bandwidth is limited by the motor load Power dissipation and thermal limits must be observed 6.4 Thermal Information DRV8886 THERMAL METRIC (1) PWP (HTSSOP) RHR (WQFN) UNIT 24 PINS 28 PINS RθJA Junction-to-ambient thermal resistance 33.8 33.2 °C/W RθJC(top) Junction-to-case (top) thermal resistance 18.0 23.1 °C/W RθJB Junction-to-board thermal resistance 7.7 12.2 °C/W ψJT Junction-to-top characterization parameter 0.2 0.3 °C/W ψJB Junction-to-board characterization parameter 7.8 12.0 °C/W RθJC(bot) Junction-to-case (bottom) thermal resistance 1.3 3.3 °C/W (1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report. Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 5 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com 6.5 Electrical Characteristics at TA = -40 to 125°C, VVM = 8 to 37 V (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT POWER SUPPLIES (VM, DVDD, AVDD) VVM VM operating voltage 8 ENABLE = 1, nSLEEP = 1, No motor load IVM VM operating supply current IVMQ VM sleep mode supply current tSLEEP Sleep time nSLEEP = 0 to sleep-mode tWAKE Wake-up time tON Turn-on time VDVDD Internal regulator voltage 0- to 1-mA external load VAVDD Internal regulator voltage No external load 5 37 V 8 mA nSLEEP = 0; TA = 25°C 20 nSLEEP = 0; TA = 125°C (1) 40 μA 50 200 μs nSLEEP = 1 to output transition 0.85 1.5 ms VM > UVLO to output transition 0.85 1.5 ms 2.9 3.3 3.6 V 4.5 5 5.5 V CHARGE PUMP (VCP, CPH, CPL) VVCP VCP operating voltage VM + 5.5 V LOGIC-LEVEL INPUTS (STEP, DIR, ENABLE, nSLEEP, M1) VIL Input logic-low voltage VIH Input logic-high voltage VHYS Input logic hysteresis IIL Input logic-low current VIN = 0 V IIH Input logic-high current VIN = 5 V RPD Pulldown resistance To GND Propagation delay STEP to current change tPD (1) 0 0.8 1.6 5.3 200 –1 V V mV 1 100 100 μA μA kΩ 1.2 μs 0.65 V 1.25 V 5.3 V TRI-LEVEL INPUT (M0, TRQ) VIL Tri-level input logic low voltage VIZ Tri-level input Hi-Z voltage 0 VIH Tri-level input logic high voltage IIL Tri-level input logic low current VIN = 0 V IIH Tri-level input logic high current VIN = 5 V RPD Tri-level pulldown resistance VIN = Hi-Z, to GND RPU Tri-level pullup resistance VIN = Hi-Z, to DVDD 0.95 1.1 1.5 –90 μA 155 μA 65 kΩ 130 kΩ QUAD-LEVEL INPUT (DECAY) VI1 Quad-level input voltage 1 Can set with 1% 5 kΩ to GND 0 0.14 V VI2 Quad-level input voltage 2 Can set with 1% 15 kΩ to GND 0.24 0.46 V VI3 Quad-level input voltage 3 Can set with 1% 44.2 kΩ to GND 0.71 1.24 V VI4 Quad-level input voltage 4 Can set with 1% 133 kΩ to GND 2.12 5.3 V IO Output current To GND 27.25 μA 17 22 CONTROL OUTPUTS (nFAULT) VOL Output logic-low voltage IO = 1 mA, RPULLUP = 4.7 kΩ IOH Output logic-high leakage VO = 5 V, RPULLUP = 4.7 kΩ (1) 6 –1 0.5 V 1 μA Specified by design and characterization data Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 Electrical Characteristics (continued) at TA = -40 to 125°C, VVM = 8 to 37 V (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT MOTOR DRIVER OUTPUTS (AOUT1, AOUT2, BOUT1, BOUT2) RDS(ON) High-side FET on resistance VM = 24 V, I = 1.4 A, TA = 25°C 290 346 mΩ RDS(ON) Low-side FET on resistance VM = 24 V, I = 1.4 A, TA = 25°C 260 320 mΩ tRISE (1) Output rise time 100 ns tFALL (1) Output fall time 100 ns Output dead time 200 (1) tDEAD Vd (1) Body diode forward voltage IOUT = 0.5 A ns 0.7 1 V 28.1 30 31.9 kAΩ 1.18 1.232 1.28 V PWM CURRENT CONTROL (RREF) ARREF RREF transimpedance gain VRREF RREF voltage tOFF PWM off-time CRREF Equivalent capacitance on RREF tBLANK ΔITRIP PWM blanking time Current trip accuracy RREF = 18 to 132 kΩ 20 μs 10 IRREF = 2.0 A, 63% to 100% current setting 1.5 µs IRREF = 2.0 A, 0% to 63% current setting 1 IRREF = 1.5 A, 10% to 20% current setting, 1% reference resistor –15% 15% IRREF = 1.5 A, 20% to 63% current setting, 1% reference resistor –10% 10% –6.25% 6.25% 7 7.8 7.2 8 IRREF = 1.5 A, 71% to 100% current setting, 1% reference resistor pF PROTECTION CIRCUITS VM falling, UVLO report VUVLO VM UVLO VUVLO,HYS Undervoltage hysteresis Rising to falling threshold 200 VCPUV Charge pump undervoltage VCP falling; CPUV report VM + 2 IOCP Overcurrent protection trip level Current through any FET tOCP (1) tRETRY VM rising, UVLO recovery Overcurrent deglitch time Overcurrent retry time TTSD Die temperature TJ THYS (1) Thermal shutdown hysteresis Die temperature TJ V A 1.9 1 Thermal shutdown temperature mV 3 1.3 (1) V 2.8 μs 1.6 ms 150 °C 20 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 °C 7 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com 6.6 Indexer Timing Requirements at TA = -40 to 125°C, VVM = 8 to 37 V (unless otherwise noted) NO. (1) MIN (1) UNIT 500 kHz 1 ƒSTEP 2 tWH(STEP) Pulse duration, STEP high 970 ns 3 tWL(STEP) Pulse duration, STEP low 970 ns 4 tSU(DIR, Mx) Setup time, DIR or USMx to STEP rising 200 ns 5 tH(DIR, Hold time, DIR or USMx to STEP rising 200 ns Mx) Step frequency MAX STEP input can operate up to 500 kHz, but system bandwidth is limited by the motor load. 1 2 3 STEP DIR, Mx 4 5 Figure 1. Timing Diagram 8 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 6.7 Typical Characteristics Over recommended operating conditions (unless otherwise noted) 7 7 TA = 40°C TA = 25°C TA = 125°C 6.8 6.8 Supply Current (mA) Supply Current (mA) 6.6 6.4 6.2 6 5.8 5.6 6.6 6.4 6.2 6 5.4 5 5 10 15 20 25 Supply Voltage (V) 30 35 5.6 -40 40 20 18 18 Sleep Current (PA) 16 14 12 10 8 TA = 40°C TA = 25°C TA = 125°C 6 15 20 25 Supply Voltage (V) 30 35 10 6 -40 40 VM = 8 V VM = 24 V VM = 37 V -20 0.38 0.4 0.36 High-Side RDS(ON) (:) High-Side RDS(ON) (:) 0.45 0.35 0.3 0.25 0.2 0.15 30 120 140 D004 D002 35 0.34 0.32 0.3 0.28 VM = 8 V VM = 24 V VM = 37 V 0.24 0 20 25 Supply Voltage (V) 20 40 60 80 100 Ambient Temperature (°C) 0.26 TA = 40°C TA = 25°C TA = 125°C 15 0 Figure 5. Sleep Current over Temperature 0.4 10 D002 12 Figure 4. Sleep Current over VM 5 140 14 0.5 0.05 120 16 D003 0.1 20 40 60 80 100 Ambient Temperature (°C) 8 4 10 0 Figure 3. Supply Current over Temperature 20 5 -20 D001 Figure 2. Supply Current over VM Sleep Current (PA) VM = 8 V VM = 24 V VM = 37 V 5.8 5.2 40 0.22 -40 -20 D005 Figure 6. High-Side RDS(ON) over VM 0 20 40 60 80 100 Ambient Temperature (°C) 120 140 D006 Figure 7. High-Side RDS(ON) over Temperature Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 9 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com Typical Characteristics (continued) Over recommended operating conditions (unless otherwise noted) 0.42 0.4 0.4 0.38 Low-Side RDS(ON) (:) Low-Side RDS(ON) (:) 0.5 0.45 0.35 0.3 0.25 0.2 0.15 0.1 10 15 20 25 Supply Voltage (V) 30 35 0.32 0.3 0.28 0.26 VM = 8 V VM = 24 V VM = 37 V 0.22 0.2 -40 0 5 0.34 0.24 TA = 40°C TA = 25°C TA = 125°C 0.05 0.36 40 -20 0 D007 Figure 8. Low-Side RDS(ON) over VM 20 40 60 80 100 Ambient Temperature (°C) 140 D008 Figure 9. Low-Side RDS(ON) over Temperature 2 3.339 TRQ = 0 3.336 3.333 3.33 1 TRQ = Z 0.7 TRQ = 1 0.5 3.327 0.3 3.324 IF S (A ) D V D D V o lta g e ( V ) 120 3.321 3.318 3.315 T A = 125°C 3.312 T A = 85°C 3.309 0.2 0.1 0.07 0.05 T A = 25°C 0.03 T A = -40°C 0.02 3.306 3.303 0.01 0 0.1 0.2 0.3 0.4 0.5 0.6 DVDD Load (mA) 0.7 0.8 0.9 1 Figure 10. DVDD Regulator over Load (VM = 24 V) 10 10 20 30 40 50 60 70 R REF (k:) D009 100 200 300 D010 Figure 11. Full-Scale Current over RREF Selection Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 7 Detailed Description 7.1 Overview The DRV8886 device is an integrated motor-driver solution for bipolar stepper motors. The device integrates two N-channel power MOSFET H-bridges, integrated current sense and regulation circuitry, and a microstepping indexer. The DRV8886 device can be powered with a supply voltage from 8 to 37 V and is capable of providing an output current up to 3-A peak, 2-A full-scale, or 1.4-A root mean square (rms). The actual full-scale and rms current depends on the ambient temperature, supply voltage, and PCB thermal capability. The DRV8886 device uses an integrated current-sense architecture which eliminates the need for two external power sense resistors. This architecture removes the power dissipated in the sense resistors by using a current mirror approach and using the internal power MOSFETs for current sensing. The current regulation set point is adjusted with a standard low-power resistor connected to the RREF pin. This features reduces external component cost, board PCB size, and system power consumption. A simple STEP/DIR interface allows for an external controller to manage the direction and step rate of the stepper motor. The internal indexer can execute high-accuracy microstepping without requiring the external controller to manage the winding current level. The indexer is capable of full step, half step, and 1/4, 1/8, 1/16 microstepping. In addition to a standard half stepping mode, a non-circular half stepping mode is available for increased torque output at higher motor RPM. The current regulation is configurable between several decay modes. The decay mode can be selected as a fixed slow, slow-mixed, or mixed decay current regulation scheme. The slow-mixed decay mode uses slow decay on increasing steps and mixed decay on decreasing steps. An adaptive blanking time feature automatically scales the minimum drive time with output current level. This feature helps alleviate zero-crossing distortion by limiting the drive time at low-current steps. A torque DAC feature allows the controller to scale the output current without needing to scale the RREF reference resistor. The torque DAC is accessed using a digital input pin which allows the controller to save system power by decreasing the motor current consumption when high output torque is not required. A low-power sleep mode is included which allows the system to save power when not actively driving the motor. Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 11 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com 7.2 Functional Block Diagram VM 0.01 F VM 0.01 F Bulk VM VM 0.22 F Power VCP AOUT1 CPH Charge Pump 0.022 F CPL Current Sense AVDD AVDD Regulator 0.47 F DVDD Stepper Motor VM Gate Drivers DVDD Regulator AOUT2 0.47 F GND Digital Core STEP Current Sense IREF PGND SINE DAC VM DIR ENABLE BOUT1 nSLEEP Current Sense Control Inputs M1 Microstepping Indexer DVDD M0 VM Gate Drivers BOUT2 Adaptive Blanking DVDD TRQ DVDD IREF Current Sense PGND DECAY SINE DAC DVDD VCC IREF Protection Fault Output Overcurrent RREF RREF RREF Analog Input RPU nFAULT Undervoltage Overtemperature PPAD Copyright © 2017, Texas Instruments Incorporated 12 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 7.3 Feature Description Table 1 lists the recommended external components for the DRV8886 device. Table 1. DRV8886 External Components COMPONENT PIN 1 PIN 2 CVM1 VM GND Two X5R or X7R, 0.01-µF, VM-rated ceramic capacitors CVM2 VM GND Bulk, VM-rated capacitor CVCP VCP VM X5R or X7R, 0.22-µF, 16-V ceramic capacitor CSW CPH CPL X5R or X7R, 0.022-µF, VM-rated ceramic capacitor CAVDD AVDD GND X5R or X7R, 0.47-µF, 6.3-V ceramic capacitor GND X5R or X7R, 0.47-µF, 6.3-V ceramic capacitor CDVDD RnFAULT RREF (1) RECOMMENDED DVDD VCC (1) nFAULT RREF >4.7-kΩ resistor Resistor to limit chopping current must be installed. See the Typical Application section for value selection. GND VCC is not a pin on the DRV8886 device, but a VCC supply voltage pullup is required for open-drain output nFAULT; nFAULT may be pulled up to DVDD 7.3.1 Stepper Motor Driver Current Ratings Stepper motor drivers can be classified using three different numbers to describe the output current: peak, rms, and full-scale. 7.3.1.1 Peak Current Rating The peak current in a stepper driver is limited by the overcurrent protection trip threshold, IOCP. The peak current describes any transient duration current pulse, for example when charging capacitance, when the overall duty cycle is very low. In general the minimum value of IOCP specifies the peak current rating of the stepper motor driver. For the DRV8886 device, the peak current rating is 3 A per bridge. 7.3.1.2 rms Current Rating The rms (average) current is determined by the thermal considerations of the device. The rms current is calculated based on the RDS(ON), rise and fall time, PWM frequency, device quiescent current, and package thermal performance in a typical system at 25°C. The actual operating rms current may be higher or lower depending on heatsinking and ambient temperature. For the DRV8886 device, the rms current rating is 1.4 A per bridge. 7.3.1.3 Full-Scale Current Rating The full-scale current describes the top of the sinusoid current waveform while microstepping. Because the sinusoid amplitude is related to the rms current, the full-scale current is also determined by the thermal considerations of the device. The full-scale current rating is approximately √2 × IRMS. The full-scale current is set by the RREF pin and the torque DAC when configuring the DRV8886 device, for details see the Current Regulation section. For the DRV8886 device, the full-scale current rating is 2 A per bridge. Full-scale current Output Current RMS current AOUT BOUT Step Input Figure 12. Full-Scale and rms Current Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 13 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com 7.3.2 PWM Motor Drivers The DRV8886 device has drivers for two full H-bridges to drive the two windings of a bipolar stepper motor. Figure 13 shows a block diagram of the circuitry. VM xOUT1 Current Sense Microstepping and Current Regulation Logic VM Gate Drivers xOUT2 Current Sense PGND Figure 13. PWM Motor Driver Block Diagram 7.3.3 Microstepping Indexer Built-in indexer logic in the DRV8886 device allows a number of different step modes. The M1 and M0 pins are used to configure the step mode as shown in Table 2. Table 2. Microstepping Settings M1 M0 STEP MODE 0 0 Full step (2-phase excitation) with 71% current 0 1 1/16 step 1 0 1/2 step 1 1 1/4 step 0 Z 1/8 step 1 Z Non-circular 1/2 step Table 3 shows the relative current and step directions for full-step through 1/16-step operation. The AOUT current is the sine of the electrical angle and the BOUT current is the cosine of the electrical angle. Positive current is defined as current flowing from the xOUT1 pin to the xOUT2 pin while driving. At each rising edge of the STEP input the indexer travels to the next state in the table. The direction is shown with the DIR pin logic high. If the DIR pin is logic low, the sequence is reversed. On power-up or when exiting sleep mode, keep the STEP pin logic low, otherwise the indexer advances one step. 14 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 NOTE If the step mode is changed from full, 1/2, 1/4, 1/8, or 1/16 to full, 1/2, 1/4, 1/8, or 1/16 while stepping, the indexer advances to the next valid state for the new step mode setting at the rising edge of STEP. If the step mode is changed from or to noncircular 1/2 step the indexer goes immediately to the valid state for that mode. The home state is an electrical angle of 45°. This state is entered after power-up, after exiting logic undervoltage lockout, or after exiting sleep mode. Table 3 lists the home state in red. Table 3. Microstepping Relative Current Per Step (DIR = 1) FULL STEP 1/2 STEP 1/4 STEP 1/8 STEP 1/16 STEP ELECTRICAL ANGLE (DEGREES) 1 1 1 1 2 2 2 3 4 1 2 3 5 6 4 7 8 3 5 9 10 6 11 12 2 4 7 13 14 8 15 16 5 9 17 18 10 19 AOUT CURRENT (% FULL-SCALE) BOUT CURRENT (% FULL-SCALE) 0.000° 0% 100% 5.625° 10% 100% 3 11.250° 20% 98% 4 16.875° 29% 96% 5 22.500° 38% 92% 6 28.125° 47% 88% 7 33.750° 56% 83% 8 39.375° 63% 77% 9 45.000° 71% 71% 10 50.625° 77% 63% 11 56.250° 83% 56% 12 61.875° 88% 47% 13 67.500° 92% 38% 14 73.125° 96% 29% 15 78.750° 98% 20% 16 84.375° 100% 10% 17 90.000° 100% 0% 18 95.625° 100% –10% 19 101.250° 98% –20% 20 106.875° 96% –29% 21 112.500° 92% –38% 22 118.125° 88% –47% 23 123.750° 83% –56% 24 129.375° 77% –63% 25 135.000° 71% –71% 26 140.625° 63% –77% 27 146.250° 56% –83% 28 151.875° 47% –88% 29 157.500° 38% –92% 30 163.125° 29% –96% 31 168.750° 20% –98% 32 174.375° 10% –100% 33 180.000° 0% –100% 34 185.625° –10% –100% 35 191.250° –20% –98% 36 196.875° –29% –96% 37 202.500° –38% –92% 38 208.125° –47% –88% Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 15 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com Table 3. Microstepping Relative Current Per Step (DIR = 1) (continued) FULL STEP 1/2 STEP 3 1/4 STEP 6 11 1/8 STEP 1/16 STEP ELECTRICAL ANGLE (DEGREES) AOUT CURRENT (% FULL-SCALE) BOUT CURRENT (% FULL-SCALE) 20 39 213.750° –56% –83% 40 219.375° –63% –77% 41 225.000° –71% –71% 42 230.625° –77% –63% 43 236.250° –83% –56% 44 241.875° –88% –47% 45 247.500° –92% –38% 46 253.125° –96% –29% 47 258.750° –98% –20% 48 264.375° –100% –10% 49 270.000° –100% 0% 50 275.625° –100% 10% 51 281.250° –98% 20% 52 286.875° –96% 29% 53 292.500° –92% 38% 54 298.125° –88% 47% 55 303.750° –83% 56% 56 309.375° –77% 63% 57 315.000° –71% 71% 58 320.625° –63% 77% 59 326.250° –56% 83% 60 331.875° –47% 88% 61 337.500° –38% 92% 62 343.125° –29% 96% 63 348.750° –20% 98% 64 354.375° –10% 100% 1 360.000° 0% 100% 21 22 12 23 24 7 13 25 26 14 27 28 4 8 15 29 30 16 31 32 1 1 1 Table 4 shows the noncircular 1/2–step operation. This stepping mode consumes more power than circular 1/2step operation, but provides a higher torque at high motor rpm. Table 4. Non-Circular 1/2-Stepping Current NON-CIRCULAR 1/2-STEP 16 AOUT CURRENT (% FULL-SCALE) BOUT CURRENT (% FULL-SCALE) 1 0 100 0 2 100 100 45 3 100 0 90 4 100 –100 135 5 0 –100 180 6 –100 –100 225 7 –100 0 270 8 –100 100 315 Submit Documentation Feedback ELECTRICAL ANGLE (DEGREES) Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 7.3.4 Current Regulation The current through the motor windings is regulated by an adjustable, fixed-off-time PWM current-regulation circuit. When an H-bridge is enabled, current rises through the winding at a rate dependent on the supply voltage, inductance of the winding, and the magnitude of the back EMF present. When the current hits the current regulation threshold, the bridge enters a decay mode for a fixed 20 μs, period of time to decrease the current. After the off time expires, the bridge is re-enabled, starting another PWM cycle. Motor Current (A) ITRIP tBLANK tDRIVE tOFF Figure 14. Current Chopping Waveform The PWM regulation current is set by a comparator which monitors the voltage across the current sense MOSFETs in parallel with the low-side power MOSFETs. The current sense MOSFETs are biased with a reference current that is the output of a current-mode sine-weighted DAC whose full-scale reference current is set by the current through the RREF pin. An external resistor is placed from the RREF pin to GND to set the reference current. In addition, the TRQ pin can further scale the reference current. Use Equation 1 to calculate the full-scale regulation current. ARREF (kA:) 30 (kA:) IFS (A) u TRQ (%) u TRQ (%) RREF (k :) RREF (k:) (1) For example, if a 30-kΩ resistor is connected to the RREF pin, the full-scale regulation current is 1 A (TRQ at 100%). The TRQ pin is the input to a DAC used to scale the output current. Table 5 lists the current scalar value for different inputs. Table 5. Torque DAC Settings TRQ CURRENT SCALAR (TRQ) 0 100% Z 75% 1 50% Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 17 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com 7.3.5 Controlling RREF With an MCU DAC In some cases, the full-scale output current may need to be changed between many different values, depending on motor speed and loading. The reference current of the RREF pin can be adjusted in the system by tying the RREF resistor to a DAC output instead of GND. In this mode of operation, as the DAC voltage increases, the reference current decreases and therefore the fullscale regulation current decreases as well. For proper operation, the output of the DAC should not rise above VRREF. DVDD IREF Controller RREF Analog Input RREF RREF DAC Figure 15. Controlling RREF With a DAC Resource Use Equation 2 to calculate the full-scale regulation current as controlled by a controller DAC. IFS (A) $RREF N$: u > 9RREF 9 ± 9DAC 9 VRREF (V) u RREF (k :) @ u TRQ (%) (2) For example, if a 20-kΩ resistor is connected from the RREF pin to the DAC, and the DAC outputs 0.74 V, the chopping current is 600 mA (TRQ at 100%) The RREF pin can also be adjusted using a PWM signal and low-pass filter. DVDD IREF Controller RREF PWM R1 R2 RREF RREF Analog Input C1 Figure 16. Controlling RREF With a PWM Resource 7.3.5.1 Various Sources of Error When performing a design error calculation, the different variables that contribute the most to the error must be considered. To do so, first consider the typical values extracted from DRV8885 data sheet which are listed in Table 6 with a 20-kΩ 1% resistor . 18 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 Table 6. DRV8885 Data Sheet Values Parameter ARREF Minimum Typical Maximum 28100 30000 31900 VRREF 1.18 1.232 1.28 RREF 19800 20000 20200 Using and knowing the desired output current, the VDAC value can be obtained. For example, the DRV8885EVM, which has a 20-kΩ resistor for RREF, was selected to operate at a 1-A, 400mA, and 200 mA current. Table 7 lists the calculated VDAC values using typical ARREF and VRREF data sheet values Table 7. VDAC Calculation Parameter IFS ARREF Minimum Typical 1 0.4 Maximum 0.2 30 000 30 000 30 000 VRREF 1.232 1.232 1.232 RREF 20 000 20 000 20 000 VDAC 0.4107 0.9035 1.0677 Next, use Equation 3 and Equation 4 to calculate the worst case value for the minimum and maximum full scale current, respectively. ARREFmin (kA:) u [VRREFmin (V) VDACmax (V)] u TRQ (%) IFSmin (A) VRREFmin (V) u RREFmax (k:) (3) IFSmax (A) ARREFmax (kA:) u [VRREFmax (V) VDACmin (V)] VRREFmax (V) u RREFmin (k:) u TRQ (%) (4) These two equations show that error contributions come from VDAC, ARREF, VRREF, and RREF. The next sections will show how these different error contributors, affect the overall IFS error and how they can be improved. 7.3.5.1.1 VRREF, ARREF, and RREF Error To observe how VRREF, ARREF, and RREFVRREF affect the IFS error , Equation 3 and Equation 4 are used with the data sheet values from earlier while VDAC voltage remains constant. Table 8, Table 9, and Table 10 list the results at different current levels (1 A, 400 mA, and 200 mA, respectively). Table 8. Worst Case Calculation—IFS Error at 1 A Parameter Minimum Typical Maximum VDAC 0.4107 0.4107 0.4107 ARREF 28100 30000 31900 VRREF 1.18 1.232 1.28 RREF 19800 20000 20200 IFS (mA) 906.95 1000 1094.21 Error (%) –9.30 9.42 Table 9. Worst Case Calculation—IFS Error at 400 mA Parameter Minimum Typical Maximum VDAC 0.9035 0.9035 0.9035 ARREF 28100 30000 31900 VRREF 1.18 1.232 1.28 RREF 19800 20000 20200 IFS (mA) 326.00 400 473.93 Error (%) –18.50 18.48 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 19 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com Table 10. Worst Case Calculation—IFS Error at 200 mA Parameter Minimum Typical Maximum VDAC 1.0677 1.0677 1.0677 ARREF 28100 30000 31900 VRREF 1.18 1.232 1.28 RREF 19800 20000 20200 IFS (mA) 135.35 200 267.18 Error (%) –33.83 33.59 These tables show that as the IFS current level decreases, the overall error percentage increases due to increasing offset error from the internal signal chain. It is worthy to clarify that the VRREF and ARREF values in these tables are data sheet values which represent the characterization data variation across a wide range of temperatures and voltages with additional margin. For information on how to further minimize this percentage of error based on targeted characterization data for VRREF and ARREF, see Application-Specific Error Calculations . 7.3.5.1.2 VDAC Error Using the same methodology along with Equation 3 and Equation 4, the VDAC error contribution to IFS can be shown. This is done by removing the error from VRREF, ARREF, and RREF. The following examples show the VDAC error value with a 3% and 10% variation. Table 11. Worst Case Calculation—VDAC 3% and 10%, IFS Error at 1 A Parameter Minimum Typical Maximum VDAC 0.3983 0.4107 0.423 ARREF 30000 30000 30000 VRREF 1.232 1.232 1.232 RREF 20000 20000 20000 IFS (mA) 985.08 1000 1015.07 Error (%) –1.50 3% ERROR 1.50 10% ERROR VDAC 0.3696 0.4107 0.4517 ARREF 30000 30000 30000 VRREF 1.232 1.232 1.232 RREF 20000 20000 20000 IFS (mA) 950.08 1000 1050.07 Error (%) –5.00 5.00 Table 12. Worst Case Calculation—VDAC 3% and 10%, IFS Error at 400 mA Parameter Minimum Typical Maximum VDAC 0.8764 0.9035 0.9306 ARREF 30000 30000 31 900 VRREF 1.232 1.232 1.232 RREF 20000 20000 20000 IFS (mA) 367.18 400 433.17 Error (%) –8.25 3% ERROR 8.25 10% ERROR 20 VDAC 0.8131 0.9035 0.9938 ARREF 30000 30000 30000 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 Table 12. Worst Case Calculation—VDAC 3% and 10%, IFS Error at 400 mA (continued) Parameter Minimum Typical Maximum 1.232 1.232 1.232 RREF 20000 20000 20000 IFS (mA) 290.19 400 510.16 Error (%) –27.48 VRREF 27.48 Table 13. Worst Case Calculation—VDAC 3% and 10%, IFS Error at 200 mA Parameter Minimum Typical Maximum VDAC 1.0357 1.0677 1.0998 ARREF 30000 30000 30000 VRREF 1.232 1.232 1.232 RREF 20000 20000 20000 IFS (mA) 161.22 200 239.20 Error (%) –19.48 3% ERROR 19.48 10% ERROR VDAC 0.9610 1.0677 1.1745 ARREF 30000 30000 30000 VRREF 1.232 1.232 1.232 RREF 20000 20000 20000 IFS (mA) 70.23 200 330.19 Error (%) –64.92 64.92 These tables show that as the variation in VDAC increases, the error percentage increases. Also, for very low currents, the error percentage increases greatly because of the VDAC proximity to the VRREF voltage. 7.3.5.2 Application-Specific Error Calculations As described in the previous analysis, it is possible to obtain a tighter error calculations by using values for VRREF and ARREF for the specific application use case. The data sheet parameters represent limits based on design and characterization data across a wide range of temperatures and voltage with additional margin. For the following example, the operational voltage is limited to VVM = 24 V, a common operating point for the DRV8884, DRV8885, DRV8886, and DRV8886AT. Considering this use case, Table 14 provides updated values for VRREF and ARREF. Table 14. Values For DRV8885 VVM= 24-V Parameter Minimum Typical Maximum ARREF 28800 30000 31200 VRREF 1.207 1.232 1.257 RREF 19800 20000 20200 Using values above and maintaining VDAC constant, the error percentage is reduced as shown in the following tables. Table 15. IFS Error at 1 A, VDAC Fixed and Application Values Parameter Minimum Typical Maximum VDAC 0.4107 0.4107 0.4107 ARREF 28800 30000 31200 VRREF 1.207 1.232 1.257 RREF 19800 20000 20200 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 21 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com Table 15. IFS Error at 1 A, VDAC Fixed and Application Values (continued) Parameter Minimum Typical Maximum IFS (mA) 940.79 1000 1060.8 Error (%) –5.93 6.07 Table 16. IFS Error at 400 mA, VDAC Fixed and Application Values Parameter Minimum Typical Maximum VDAC 0.9035 0.9035 0.9035 ARREF 28800 30000 31200 VRREF 1.207 1.232 1.257 RREF 19800 20000 20200 IFS (mA) 358.54 400 443.18 Error (%) –10.4 10.75 Table 17. IFS Error at 200 mA, VDAC Fixed and Application Values Parameter Minimum Typical Maximum VDAC 1.0677 1.0677 1.0677 ARREF 28800 30000 31200 VRREF 1.207 1.232 1.257 RREF 19800 20000 20200 IFS (mA) 164.51 200 267.26 Error (%) –17.83 18.51 By keeping VDAC value fixed or close to be fixed, yields much less error variation. The same calculation can be made using a VDAC value with a ±3 % variation to compare error percentage difference as shown in the following tables. Table 18. VDAC 3%, VRREF and ARREF for 24-V Application at 1 A Parameter Minimum Typical Maximum VDAC 0.3983 0.4107 0.4230 ARREF 28800 30000 31200 VRREF 1.207 1.232 1.257 RREF 19800 20000 20200 IFS (mA) 926.09 1000 1076.39 Error (%) –7.4 7.63 Table 19. VDAC 3%, VRREF and ARREF for 24-V Application at 400 mA Parameter 22 Minimum Typical Maximum VDAC 0.8764 0.9035 0.9306 ARREF 28800 30000 31200 VRREF 1.207 1.232 1.257 RREF 19800 20000 20200 IFS (mA) 326.52 400 477.16 Error (%) –18.41 Submit Documentation Feedback 19.24 Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 Table 20. VDAC 3%, VRREF and ARREF for 24-V Application at 200 mA Parameter Minimum Typical Maximum VDAC 1.0357 1.0677 1.0998 ARREF 28800 30000 31200 VRREF 1.207 1.232 1.257 RREF 19800 20000 20200 IFS (mA) 126.67 200 277.42 Error (%) –36.73 38.56 Table 18, Table 19, and Table 20 show values closer to the typical values for both VDAC, ARREF, and VRREF. From all these calculations, the error percentages for the 200 mA current are higher because at those very low values, the minimum change greatly affects the full current equation. One method to improve the low-value current accuracy is to use a combination of the MCU DAC and TRQ pin. This method can help improve the error by reducing the need to use only the DAC voltage to achieve the low full-scale current. An example of this method is to achieve 200 mA using the 400 mA DAC setting and the 50% TRQ setting. Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 23 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com 7.3.6 Decay Modes The DRV8886 decay mode is selected by setting the quad-level DECAY pin to the voltage range listed in Table 21. The decay mode setting can be modified during device operation. Table 21. Decay Mode Settings DECAY INCREASING STEPS DECREASING STEPS 100 mV Can be tied to ground Slow decay Mixed decay: 30% fast 300 mV, 15 kΩ to GND Mixed decay: 30% fast Mixed decay: 30% fast 1 V, 45 kΩ to GND Mixed decay: 60% fast Mixed decay: 60% fast 2.9 V Can be tied to DVDD Slow decay Slow decay AOUT Current Figure 17 defines increasing and decreasing current. For the slow-mixed decay mode, the decay mode is set as slow during increasing current steps and mixed decay during decreasing current steps. In full step mode the decreasing steps decay mode is always used. In noncircular 1/2-step mode the increasing step decay mode is used after a level transition (0% to 100% and 0% to –100%). When the level transition is to a similar level (100% to 100% and –100% to –100%), the decreasing step decay mode is used. Increasing Decreasing Increasing Decreasing STEP Input BOUT Current AOUT Current Decreasing Increasing Increasing Decreasing STEP Input Figure 17. Definition of Increasing and Decreasing Steps 24 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 7.3.6.1 Mode 1: Slow Decay for Increasing Current, Mixed Decay for Decreasing Current Increasing Phase Current (A) ITRIP tBLANK tOFF tBLANK tOFF tDRIVE Decreasing Phase Current (A) tDRIVE tBLANK tDRIVE ITRIP tBLANK tDRIVE tFAST tBLANK tOFF tFAST tDRIVE tOFF Figure 18. Slow-Mixed Decay Mode Mixed decay begins as fast decay for a time, followed by slow decay for the remainder of the tOFF time. In this mode, mixed decay only occurs during decreasing current. Slow decay is used for increasing current. This mode exhibits the same current ripple as slow decay for increasing current because for increasing current, only slow decay is used. For decreasing current, the ripple is larger than slow decay, but smaller than fast decay. On decreasing current steps, mixed decay will settle to the new ITRIP level faster than slow decay. Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 25 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com 7.3.6.2 Mode 2: Mixed Decay for Increasing and Decreasing Current Increasing Phase Current (A) ITRIP tOFF tBLANK tOFF tDRIVE Decreasing Phase Current (A) tDRIVE tBLANK tDRIVE ITRIP tBLANK tDRIVE tFAST tBLANK tOFF tFAST tDRIVE tOFF Figure 19. Mixed-Mixed Decay Mode Mixed decay begins as fast decay for a time, followed by slow decay for the remainder of tOFF. In this mode, mixed decay occurs for both increasing and decreasing current steps. This mode exhibits ripple larger than slow decay, but smaller than fast decay. On decreasing current steps, mixed decay settles to the new ITRIP level faster than slow decay. In cases where current is held for a long time (no input in the STEP pin) or at very low stepping speeds, slow decay may not properly regulate current because no back-EMF is present across the motor windings. In this state, motor current can rise very quickly, and requires an excessively large off-time. Increasing or decreasing mixed decay mode allows the current level to stay in regulation when no back-EMF is present across the motor windings. 26 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 7.3.6.3 Mode 3: Slow Decay for Increasing and Decreasing Current Increasing Phase Current (A) ITRIP tBLANK tOFF tBLANK tOFF tDRIVE Decreasing Phase Current (A) tDRIVE ITRIP tBLANK tOFF tBLANK tDRIVE tDRIVE tOFF tBLANK tDRIVE Figure 20. Slow-Slow Decay Mode During slow decay, both of the low-side MOSFETs of the H-bridge are turned on, allowing the current to be recirculated. Slow decay exhibits the least current ripple of the decay modes for a given tOFF. However, on decreasing current steps, slow decay takes a long time to settle to the new ITRIP level because the current decreases very slowly. Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 27 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com 7.3.7 Blanking Time After the current is enabled in an H-bridge, the current sense comparator is ignored for a period of time (tBLANK) before enabling the current-sense circuitry. The blanking time also sets the minimum drive time of the PWM. Table 22 shows the blanking time based on the sine table index and the torque DAC setting. The torque DAC index is not the same as one step as given in Table 3. Table 22. Adaptive Blanking Time over Torque DAC and Microsteps tblank = 1.5 µs SINE INDEX 28 tblank = 1 µs TORQUE DAC (TRQ) 100% 75% 50% 16 100% 75% 50% 15 98% 73.5 49% 14 96% 72% 48% 13 92% 69% 46% 12 88% 66% 44% 11 83% 62.3% 41.5% 10 77% 57.8% 38.5% 9 71% 53.3% 35.5% 8 63% 47.3% 31.5% 7 56% 42% 28% 6 47% 35.3 23.5% 5 38% 28.5 19% 4 29% 21.8% 14.5% 3 20% 15% 10% 2 10% 7.5% 5% 1 0% 0% 0% Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 7.3.8 Charge Pump A charge pump is integrated to supply a high-side N-channel MOSFET gate-drive voltage. The charge pump requires a capacitor between the VM and VCP pins to act as the storage capacitor. Additionally a ceramic capacitor is required between the CPH and CPL pins to act as the flying capacitor. VM VM 0.22 …F VCP CPH 0.022 …F VM Charge Pump Control CPL Figure 21. Charge Pump Block Diagram Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 29 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com 7.3.9 Linear Voltage Regulators An linear voltage regulator is integrated into the DRV8886 device. The DVDD regulator can be used to provide a reference voltage. For proper operation, bypass the DVDD pin to GND using a ceramic capacitor. The DVDD output is nominally 3.3 V. When the DVDD LDO current load exceeds 1 mA, the output voltage drops significantly. The AVDD pin also requires a bypass capacitor to GND. This LDO is for DRV8886 internal use only. VM + ± DVDD 3.3-V, 1-mA 0.47 …F VM + ± AVDD 0.47 …F Figure 22. Linear Voltage Regulator Block Diagram If a digital input must be tied permanently high (that is, Mx, DECAY or TRQ), tying the input to the DVDD pin instead of an external regulator is preferred. This method saves power when the VM pin is not applied or in sleep mode: the DVDD regulator is disabled and current does not flow through the input pulldown resistors. For reference, logic level inputs have a typical pulldown of 100 kΩ, and tri-level inputs have a typical pulldown of 60 kΩ. 7.3.10 Logic and Multi-Level Pin Diagrams Figure 23 shows the input structure for the logic-level pins STEP, DIR, ENABLE, nSLEEP, and M1. DVDD 100 kŸ Figure 23. Logic-Level Input Pin Diagram The tri-level logic pins, M0 and TRQ, have the structure shown in Figure 24. 30 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 DVDD DVDD + - 60 kŸ DVDD 32 kŸ + - Figure 24. Tri-Level Input Pin Diagram The quad-level logic pin, DECAY, has the structure shown in Figure 25. DVDD + DVDD 20 µA t DVDD + tDVDD + t Figure 25. Quad-Level Input Pin Diagram 7.3.11 Protection Circuits The DRV8886 device is fully protected against supply undervoltage, charge pump undervoltage, output overcurrent, and device overtemperature events. 7.3.11.1 VM Undervoltage Lockout (UVLO) If at any time the voltage on the VM pin falls below the VM undervoltage-lockout threshold voltage (VUVLO), all MOSFETs in the H-bridge are disabled, the charge pump is disabled, the logic is reset, and the nFAULT pin is driven low. Operation resumes when the VM voltage rises above the VUVLO threshold. The nFAULT pin is released after operation resumes. Decreasing the VM voltage below this undervoltage threshold resets the indexer position. 7.3.11.2 VCP Undervoltage Lockout (CPUV) If at any time the voltage on the VCP pin falls below the charge-pump undervoltage-lockout threshold voltage (VCPUV), all MOSFETs in the H-bridge are disabled and the nFAULT pin is driven low. Operation resumes when the VCP voltage rises above the VCPUV threshold. The nFAULT pin is released after operation resumes. 7.3.11.3 Overcurrent Protection (OCP) An analog current-limit circuit on each MOSFET limits the current through the MOSFET by removing the gate drive. If this analog current limit persists for longer than tOCP, all MOSFETs in the H-bridge are disabled and the nFAULT pinis driven low. Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 31 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com The driver is re-enabled after the OCP retry period (tRETRY) has passed. The nFAULT pin becomes high again at after the retry time. If the fault condition is still present, the cycle repeats. If the fault is no longer present, normal operation resumes and nFAULT remains deasserted. 7.3.11.4 Thermal Shutdown (TSD) If the die temperature exceeds TTSD level, all MOSFETs in the H-bridge are disabled and the nFAULT pin is driven low. When the die temperature falls below the TTSD level, operation automatically resumes. The nFAULT pin is released after operation resumes. Table 23. Fault Condition Summary FAULT CONDITION ERROR REPORT H-BRIDGE CHARGE PUMP INDEXER DVDD AVDD RECOVERY VM undervoltage (UVLO) VM < VUVLO (max 7.8 V) nFAULT Disabled Disabled Disabled Operating Disabled VM > VUVLO (max 8 V) VCP undervoltage (CPUV) VCP < VCPUV (typ VM + 2 V) nFAULT Disabled Operating Operating Operating Operating VCP > VCPUV (typ VM + 2.7 V) Overcurrent (OCP) IOUT > IOCP (min 3 A) nFAULT Disabled Operating Operating Operating Operating tRETRY Thermal shutdown (TSD) TJ > TTSD (min 150°C) nFAULT Disabled Operating Operating Operating Operating TJ < TTSD – THYS (THYS typ 20°C) 7.4 Device Functional Modes The DRV8886 device is active unless the nSLEEP pin is brought logic low. In sleep mode the charge pump is disabled, the H-bridge MOSFETs are disabled Hi-Z, and the regulators are disabled. NOTE The tSLEEP time must elapse after a falling edge on the nSLEEP pin before the device is in sleep mode. The DRV8886 device is brought out of sleep mode automatically if nSLEEP is brought logic high. The tWAKE time must elapse before the outputs change state after wake-up. TI recommends to keep the STEP pin logic low when coming out of nSLEEP or when applying power. If the ENABLE pin is brought logic low, the H-bridge outputs are disabled, but the internal logic is still active. A rising edge on STEP advances the indexer, but the outputs do not change state until the ENABLE pin is asserted. Table 24 lists a summary of the functional modes. Table 24. Functional Modes Summary CONDITION H-BRIDGE CHARGE PUMP INDEXER DVDD AVDD Operating 8 V < VM < 40 V nSLEEP pin = 1 ENABLE pin = 1 Operating Operating Operating Operating Operating Disabled 8 V < VM < 40 V nSLEEP pin = 1 ENABLE pin = 0 Disabled Operating Operating Operating Operating Sleep mode 8 V < VM < 40 nSLEEP pin = 0 Disabled Disabled Disabled Disabled Disabled VM undervoltage (UVLO) Disabled Disabled Disabled Operating Disabled VCP undervoltage (CPUV) Disabled Operating Operating Operating Operating Overcurrent (OCP) Disabled Operating Operating Operating Operating Thermal Shutdown (TSD) Disabled Operating Operating Operating Operating Fault encountered 32 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 8 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 8.1 Application Information The DRV8886 device is used in bipolar stepper control. 8.2 Typical Application The following design procedure can be used to configure the DRV8886 device. DRV8886PWP 24 1 DECAY CPL TRQ CPH M1 VCP M0 VM 23 2 22 3 21 4 20 0.22 F VM 5 DIR 0.01 F AOUT1 6 7 + STEP ± 19 PGND 18 ENABLE AOUT2 nSLEEP BOUT2 17 Step Motor 8 16 + ± 9 RREF 15 30 k 0.022 F PGND 10 nFAULT BOUT1 14 11 DVDD VM AVDD GND 13 VM 12 0.47 F 0.01 F + 100 F 0.47 F Copyright © 2017, Texas Instruments Incorporated Figure 26. Typical Application Schematic 8.2.1 Design Requirements Table 25 lists the design input parameters for system design. Table 25. Design Parameters DESIGN PARAMETER REFERENCE EXAMPLE VALUE Supply voltage VM 24 V Motor winding resistance RL 2.6 Ω/phase Motor winding inductance LL 1.4 mH/phase θstep 1.8°/step Motor full step angle Target microstepping level Target motor speed Target full-scale current nm 1/8 step v 120 rpm IFS 2A Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 33 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com 8.2.2 Detailed Design Procedure 8.2.2.1 Stepper Motor Speed The first step in configuring the DRV8886 device requires the desired motor speed and microstepping level. If the target application requires a constant speed, then a square wave with frequency ƒstep must be applied to the STEP pin. If the target motor speed is too high, the motor does not spin. Make sure that the motor can support the target speed. Use Equation 5 to calculate ƒstep for a desired motor speed (v), microstepping level (nm), and motor full step angle (θstep). v (rpm) u 360 (q / rot) ¦step VWHSV V Tstep (q / step) u nm (steps / microstep) u 60 (s / min) (5) The value of θstep can be found in the stepper motor data sheet, or written on the motor. For the DRV8886 device, the microstepping level is set by the Mx pins and can be any of the settings listed in Table 26. Higher microstepping results in smoother motor motion and less audible noise, but increases switching losses and requires a higher ƒstep to achieve the same motor speed. Table 26. Microstepping Indexer Settings M1 M0 STEP MODE 0 0 Full step (2-phase excitation) with 71% current 0 1 1/16 step 1 0 1/2 step 1 1 1/4 step 0 Z 1/8 step 1 Z Non-circular 1/2 step For example, the motor is 1.8°/step for a target of 120 rpm at 1/8 microstep mode. 120 rpm u 360q / rot ¦step VWHSV V N+] 1.8q / step u 1/ 8 steps / microstep u 60 s / min (6) 8.2.2.2 Current Regulation In a stepper motor, the full-scale current (IFS) is the maximum current driven through either winding. This quantity depends on the RREF resistor and the TRQ setting. During stepping, IFS defines the current chopping threshold (ITRIP) for the maximum current step. ARREF (kA:) 30 (kA:) u TRQ% IFS (A) RREF (k:) RREF (k:) (7) NOTE The IFS current must also follow Equation 8 to avoid saturating the motor. VM is the motor supply voltage, and RL is the motor winding resistance. IFS (A) RL (:) VM (V) 2 u RDS(ON) (:) (8) 8.2.2.3 Decay Modes The DRV8886 device supports three different decay modes: slow decay, slow-mixed decay, and all mixed decay. The current through the motor windings is regulated using an adjustable fixed-time-off scheme which means that after any drive phase, when a motor winding current has hit the current chopping threshold (ITRIP), the DRV8886 places the winding in one of the three decay modes for tOFF. After tOFF, a new drive phase starts. The blanking time, tBLANK, defines the minimum drive time for the PWM current chopping. ITRIP is ignored during tBLANK, so the winding current may overshoot the trip level. 34 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 8.2.3 Application Curves Figure 27. 1/8 Microstepping With Slow-Slow Decay; Loss of Current Regulation on Falling Steps Figure 28. 1/8 Microstepping With Slow-Mixed Decay Figure 29. 1/8 Microstepping With Mixed30-Mixed30 Decay Figure 30. 1/8 Microstepping With Mixed60-Mixed60 Decay Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 35 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com 9 Power Supply Recommendations The DRV8886 device is designed to operate from an input voltage supply (VM) range from 8 V to 37 V. A 0.01µF ceramic capacitor rated for VM must be placed at each VM pin as close to the DRV8886 device as possible. In addition, a bulk capacitor must be included on VM. 9.1 Bulk Capacitance Having appropriate local bulk capacitance is an important factor in motor drive system design. It is generally beneficial to have more bulk capacitance, while the disadvantages are increased cost and physical size. The amount of local capacitance needed depends on a variety of factors, including: • The highest current required by the motor system • The power supply’s capacitance and ability to source current • The amount of parasitic inductance between the power supply and motor system • The acceptable voltage ripple • The type of motor used (brushed DC, brushless DC, stepper) • The motor braking method The inductance between the power supply and motor drive system will limit the rate current can change from the power supply. If the local bulk capacitance is too small, the system will respond to excessive current demands or dumps from the motor with a change in voltage. When adequate bulk capacitance is used, the motor voltage remains stable and high current can be quickly supplied. The data sheet generally provides a recommended value, but system-level testing is required to determine the appropriate sized bulk capacitor. The voltage rating for bulk capacitors should be higher than the operating voltage, to provide margin for cases when the motor transfers energy to the supply. Power Supply Parasitic Wire Inductance Motor Drive System VM + ± + Motor Driver GND Local Bulk Capacitor IC Bypass Capacitor Copyright © 2016, Texas Instruments Incorporated Figure 31. Example Setup of Motor Drive System With External Power Supply 36 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 DRV8886 www.ti.com SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 10 Layout 10.1 Layout Guidelines The VM pin should be bypassed to GND using a low-ESR ceramic bypass capacitor with a recommended value of 0.01 µF rated for VM. This capacitor should be placed as close to the VM pin as possible with a thick trace or ground plane connection to the device GND pin. The VM pin must be bypassed to ground using a bulk capacitor rated for VM. This component can be an electrolytic capacitor. A low-ESR ceramic capacitor must be placed between the CPL and CPH pins. A value of 0.022 µF rated for VM is recommended. Place this component as close to the pins as possible. A low-ESR ceramic capacitor must be placed between the VM and VCP pins. A value of 0.22 µF rated for 16 V is recommended. Place this component as close to the pins as possible. Bypass the AVDD and DVDD pins to ground with a low-ESR ceramic capacitor rated 6.3 V. Place this bypass capacitor as close to the pin as possible. 10.2 Layout Example + CPL DECAY CPH TRQ VCP M1 VM M0 AOUT1 DIR PGND STEP AOUT2 ENABLE BOUT2 nSLEEP PGND RREF BOUT1 nFAULT VM DVDD GND AVDD 0.47 µF 0.01 µF 0.47 µF 0.22 µF 0.022 µF 0.01 µF Figure 32. Layout Recommendation Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 37 DRV8886 SLVSDA4C – JANUARY 2017 – REVISED MARCH 2020 www.ti.com 11 Device and Documentation Support 11.1 Documentation Support 11.1.1 Related Documentation For related documentation see the following: • Texas Instruments, Calculating Motor Driver Power Dissipation application report • Texas Instruments, Current Recirculation and Decay Modes application report • Texas Instruments, DRV8886 Evaluation Module User's Guide • Texas Instruments, Full-Scale Current Adjustment Using a Digital-to-Analog Converter (DAC) application report • Texas Instruments, Industrial Motor Drive Solution Guide • Texas Instruments, PowerPAD™ Made Easy application report • Texas Instruments, PowerPAD™ Thermally Enhanced Package application report • Texas Instruments, Understanding Motor Driver Current Ratings application report 11.2 Receiving Notification of Documentation Updates To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper right corner, click on Alert me to register and receive a weekly digest of any product information that has changed. For change details, review the revision history included in any revised document. 11.3 Community Resources TI E2E™ support forums are an engineer's go-to source for fast, verified answers and design help — straight from the experts. Search existing answers or ask your own question to get the quick design help you need. Linked content is provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. 11.4 Trademarks PowerPAD, E2E are trademarks of Texas Instruments. All other trademarks are the property of their respective owners. 11.5 Electrostatic Discharge Caution These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. 11.6 Glossary SLYZ022 — TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. 38 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: DRV8886 PACKAGE OPTION ADDENDUM www.ti.com 8-Jun-2022 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) Samples (4/5) (6) DRV8886PWP ACTIVE HTSSOP PWP 24 60 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 125 DRV8886 Samples DRV8886PWPR ACTIVE HTSSOP PWP 24 2000 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 125 DRV8886 Samples DRV8886RHRR ACTIVE WQFN RHR 28 3000 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 125 DRV8886 Samples DRV8886RHRT ACTIVE WQFN RHR 28 250 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 125 DRV8886 Samples (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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