Product Folder Sample & Buy Technical Documents Support & Community Tools & Software DRV8814 SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 DRV8814 DC Motor Driver IC 1 Features 3 Description • • The DRV8814 provides an integrated motor driver solution for printers, scanners, and other automated equipment applications. The device has two H-bridge drivers, and is intended to drive DC motors. The output driver block for each consists of N-channel power MOSFET’s configured as H-bridges to drive the motor windings. The DRV8814 can supply up to 2.5-A peak or 1.75-A RMS output current (with proper heatsinking at 24 V and 25°C) per H-bridge. 1 • • • • • • • 8 V to 45 V Operating Supply Voltage Range 2.5 A Maximum Drive Current at 24 V and TA = 25°C Dual H-Bridge Current-Control Motor Driver – Drives Two DC Motors – Four Level Winding Current Control Multiple Decay Modes – Slow Decay – Fast Decay Industry Standard Parallel Digital Control Interface Low Current Sleep Mode Built-In 3.3-V Reference Output Small Package and Footprint Protection Features – Overcurrent Protection (OCP) – Thermal Shutdown (TSD) – VM Undervoltage Lockout (UVLO) – Fault Condition Indication Pin (nFAULT) A simple parallel digital control interface is compatible with industry-standard devices. Decay mode is programmable to allow braking or coasting of the motor when disabled. Internal shutdown functions are provided for over current protection, short circuit protection, under voltage lockout, and over temperature. The DRV8814 is available in a 28-pin HTSSOP package with PowerPAD™ (Eco-friendly: RoHS & no Sb/Br). Device Information(1) PART NUMBER PACKAGE BODY SIZE (NOM) 2 Applications DRV8814 HTSSOP (28) 9.70 mm x 4.40 mm • • • • • • (1) For all available packages, see the orderable addendum at the end of the datasheet. Printers Scanners Office Automation Machines Gaming Machines Factory Automation Robotics Simplified Schematic 8 V to 45 V ENBL Decay Mode Current Lvl nFAULT 2.5 A Stepper Motor Driver Current Control M - Controller DRV8814 + PHASE 2.5 A M 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. DRV8814 SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 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 5 6.1 6.2 6.3 6.4 6.5 6.6 5 5 5 5 6 7 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics........................................... Typical Characteristics .............................................. Detailed Description .............................................. 8 7.1 7.2 7.3 7.4 Overview ................................................................... 8 Functional Block Diagram ......................................... 8 Feature Description................................................... 9 Device Functional Modes........................................ 10 8 Application and Implementation ........................ 13 8.1 Application Information............................................ 13 8.2 Typical Application .................................................. 13 9 Power Supply Recommendations...................... 15 9.1 Bulk Capacitance .................................................... 15 9.2 Power Supply and Logic Sequencing ..................... 15 10 Layout................................................................... 16 10.1 Layout Guidelines ................................................. 16 10.2 Layout Example .................................................... 16 10.3 Thermal Considerations ........................................ 16 11 Device and Documentation Support ................. 18 11.1 11.2 11.3 11.4 11.5 Documentation Support ........................................ Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 18 18 18 18 18 12 Mechanical, Packaging, and Orderable Information ........................................................... 18 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision D (August 2013) to Revision E • 2 Page Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section ................................................................................................. 1 Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 DRV8814 www.ti.com SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 5 Pin Configuration and Functions PWP Package 28-Pin HTSSOP with PowerPAD™ Top View Pin Functions PIN NAME NO. I/O (1) EXTERNAL COMPONENTS OR CONNECTIONS DESCRIPTION POWER AND GROUND GND 14, 28 - Device ground VMA 4 - Bridge A power supply VMB 11 - Bridge B power supply V3P3OUT 15 O 3.3-V regulator output CP1 1 IO Charge pump flying capacitor CP2 2 IO Charge pump flying capacitor VCP 3 IO High-side gate drive voltage Connect a 0.1-μF 16-V ceramic capacitor and a 1-MΩ to VM. AENBL 21 I Bridge A enable Logic high to enable bridge A APHASE 20 I Bridge A phase (direction) Logic high sets AOUT1 high, AOUT2 low AI0 24 I AI1 25 I Bridge A current set Sets bridge A current: 00 = 100%, 01 = 71%, 10 = 38%, 11 = 0 BENBL 22 I Bridge B enable Logic high to enable bridge B BPHASE 23 I Bridge B phase (direction) Logic high sets BOUT1 high, BOUT2 low BI0 26 I BI1 27 I Bridge B current set Sets bridge B current: 00 = 100%, 01 = 71%, 10 = 38%, 11 = 0 DECAY 19 I Decay (brake) mode Low = brake (slow decay), high = coast (fast decay) nRESET 16 I Reset input Active-low reset input initializes internal logic and disables the H-bridge outputs nSLEEP 17 I Sleep mode input Logic high to enable device, logic low to enter low-power sleep mode AVREF 12 I Bridge A current set reference input BVREF 13 I Bridge B current set reference input Connect to motor supply (8 V to 45 V). Both pins must be connected to the same supply, bypassed with a 0.1-µF capacitor to GND, and connected to appropriate bulk capacitance. Bypass to GND with a 0.47-μF 6.3-V ceramic capacitor. Can be used to supply VREF. Connect a 0.01-μF 50-V capacitor between CP1 and CP2. CONTROL (1) Reference voltage for winding current set. Can be driven individually with an external DAC for microstepping, or tied to a reference (e.g., V3P3OUT). Directions: I = input, O = output, OZ = tri-state output, OD = open-drain output, IO = input/output Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 3 DRV8814 SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 www.ti.com Pin Functions (continued) PIN NAME NO. I/O (1) EXTERNAL COMPONENTS OR CONNECTIONS DESCRIPTION STATUS nFAULT 18 OD Fault Logic low when in fault condition (overtemp, overcurrent) ISENA 6 IO Bridge A ground / Isense Connect to current sense resistor for bridge A ISENB 9 IO Bridge B ground / Isense Connect to current sense resistor for bridge B AOUT1 5 O Bridge A output 1 AOUT2 7 O Bridge A output 2 BOUT1 10 O Bridge B output 1 BOUT2 8 O Bridge B output 2 OUTPUT 4 Connect to motor winding A Connect to motor winding B Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 DRV8814 www.ti.com SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 6 Specifications 6.1 Absolute Maximum Ratings over operating free-air temperature range, unless otherwise noted. (1) Power supply voltage range VMx Power supply ramp rate VMx Digital pin voltage range Input voltage ISENSEx pin voltage VREF (2) MIN MAX UNIT –0.3 47 V 1 V/µs –0.5 7 V –0.3 4 V –0.8 0.8 V Peak motor drive output current, t < 1 μS Internally limited A Continuous motor drive output current (3) 0 A Continuous total power dissipation 2.5 See Thermal Information Operating virtual junction temperature range, TJ –40 150 °C Operating ambient temperature range, TA –40 85 °C Storage temperature, TSTG –60 150 °C (1) (2) (3) 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. Transients of ±1 V for less than 25 ns are acceptable. Power dissipation and thermal limits must be observed. 6.2 ESD Ratings VALUE V(ESD) (1) (2) 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. 6.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) MIN (1) NOM MAX UNIT VM Motor power supply voltage range 8 45 VREF VREF input voltage (2) 1 3.5 IV3P3 V3P3OUT load current 0 1 mA fPWM Externally applied PWM frequency 0 100 kHz (1) (2) V V All VM pins must be connected to the same supply voltage. Operational at VREF between 0 V and 1 V, but accuracy is degraded. 6.4 Thermal Information DRV8814 THERMAL METRIC (1) PWP (HTSSOP) UNIT 28 PINS RθJA Junction-to-ambient thermal resistance 31.6 °C/W RθJC(top) Junction-to-case (top) thermal resistance 15.9 °C/W RθJB Junction-to-board thermal resistance 5.6 °C/W ψJT Junction-to-top characterization parameter 0.2 °C/W ψJB Junction-to-board characterization parameter 5.5 °C/W RθJC(bot) Junction-to-case (bottom) thermal resistance 1.4 °C/W (1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953. Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 5 DRV8814 SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 www.ti.com 6.5 Electrical Characteristics over operating free-air temperature range (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT POWER SUPPLIES IVM VM operating supply current VM = 24 V, fPWM 50 kHz 5 8 mA IVMQ VM sleep mode supply current VM = 24 V 10 20 μA VUVLO VM undervoltage lockout voltage VM rising 7.8 8.2 V 3.3 3.4 V V3P3OUT REGULATOR V3P3 V3P3OUT voltage IOUT = 0 to 1 mA 3.2 LOGIC-LEVEL INPUTS VIL Input low voltage VIH Input high voltage 0.6 VHYS Input hysteresis IIL Input low current VIN = 0 IIH Input high current VIN = 3.3 V 0.7 V 5.25 V 0.45 0.6 V 20 μA 33 100 μA 0.5 V 1 μA 0.8 V ±40 μA 2 0.3 –20 nFAULT OUTPUT (OPEN-DRAIN OUTPUT) VOL Output low voltage IO = 5 mA IOH Output high leakage current VO = 3.3 V DECAY INPUT VIL Input low threshold voltage For slow decay (brake) mode 0 VIH Input high threshold voltage For fast decay (coast) mode 2 IIN Input current VIN = 0 V to 3.3 V V H-BRIDGE FETS RDS(ON) HS FET on resistance RDS(ON) LS FET on resistance IOFF Off-state leakage current VM = 24 V, IO = 1 A, TJ = 25°C 0.2 VM = 24 V, IO = 1 A, TJ = 85°C 0.25 VM = 24 V, IO = 1 A, TJ = 25°C 0.2 VM = 24 V, IO = 1 A, TJ = 85°C 0.25 –20 0.32 0.32 20 Ω Ω μA MOTOR DRIVER fPWM Internal current control PWM frequency 50 kHz tBLANK Current sense blanking time tR Rise time 50 300 ns tF Fall time 50 300 ns 160 180 °C 3 μA μs 3.75 PROTECTION CIRCUITS IOCP Overcurrent protection trip level tTSD Thermal shutdown temperature 3 Die temperature 150 A CURRENT CONTROL IREF VTRIP VREF input current xISENSE trip voltage AISENSE Current sense amplifier gain 6 VREF = 3.3 V –3 xVREF = 3.3 V, 100% current setting 635 660 685 xVREF = 3.3 V, 71% current setting 445 469 492 xVREF = 3.3 V, 38% current setting 225 251 276 Reference only Submit Documentation Feedback 5 mV V/V Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 DRV8814 www.ti.com SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 6.6 Typical Characteristics 7 14 6.5 12 IVMQ (PA) IVM (mA) 6 5.5 10 5 8 -40qC 25qC 85qC 125qC 4.5 4 10 15 20 25 30 V(VMx) (V) 35 40 6 10 45 -40qC 25qC 85qC 125qC 15 Figure 1. IVMx vs V(VMx) 25 30 V(VMx) (V) 35 40 45 D002 Figure 2. IVMxQ vs V(VMx) 750 750 -40qC 25qC 85qC 125qC 700 RDS(ON) HS + LS (m:) 700 RDS(ON) HS + LS (m:) 20 D001 650 600 550 500 450 650 600 550 500 8V 24 V 45 V 450 400 8 13 18 23 28 V(VMx) (V) 33 38 400 -50 43 D003 Figure 3. RDS(ON) vs V(MVx) -25 0 25 50 TA (qC) 75 100 125 D004 Figure 4. RDS(ON) vs Temperature Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 7 DRV8814 SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 www.ti.com 7 Detailed Description 7.1 Overview The DRV8814 is an integrated motor driver solution for two brushed DC motors. The device integrates two NMOS H-bridges, current sense, regulation circuitry, and detailed fault detection. The DRV8814 can be powered with a supply voltage between 8 V and 45 V and is capable of providing an output current up to 2.5 A full-scale. A PHASE/ENBL interface allows for simple interfacing to the controller circuit. The winding current control allows the external controller to adjust the regulated current that is provided to the motor. The current regulation is highly configurable, with two decay modes of operation. Fast and slow decay can be selected depending on the application requirements. A low-power sleep mode is included which allows the system to save power when not driving the motor. 7.2 Functional Block Diagram VM VM Internal Reference & Regs 3.3V CP1 Int. VCC LS Gate Drive V3P3OUT 0.01mF CP2 VM Charge Pump VCP 3.3V 0.1mF Thermal Shut down HS Gate Drive 1MW VM AVREF VMA BVREF AOUT1 Motor Driver A APHASE AENBL DCM AOUT2 AI0 ISENA AI1 BPHASE BENBL BI0 Control Logic VM VMB BI1 BOUT1 DECAY Motor Driver B nRESET DCM BOUT2 nSLEEP ISENB nFAULT GND 8 GND Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 DRV8814 www.ti.com SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 7.3 Feature Description 7.3.1 PWM Motor Drivers The DRV8814 contains two H-bridge motor drivers with current-control PWM circuitry. A block diagram of the motor control circuitry is shown in Figure 5. VM OCP VM VCP, VGD AOUT1 Predrive AENBL DCM APHASE AOUT2 DECAY PWM OCP AISEN + AI[1:0] A=5 DAC 2 AVREF VM OCP VM VCP, VGD BOUT1 Predrive BENBL DCM BPHASE BOUT2 PWM OCP BISEN + BI[1:0] A =5 DAC 2 BVREF Figure 5. Motor Control Circuitry NOTE There are multiple VM pins. All VM pins must be connected together to the motor supply voltage. Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 9 DRV8814 SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 www.ti.com 7.4 Device Functional Modes 7.4.1 Bridge Control The xPHASE input pins control the direction of current flow through each H-bridge, and hence the direction of rotation of a DC motor. The xENBL input pins enable the H-bridge outputs when active high, and can also be used for PWM speed control of the motor. Note that the state of the DECAY pin selects the behavior of the bridge when xENBL = 0, allowing the selection of slow decay (brake) or fast decay (coast). Table 1 shows the logic. Table 1. H-Bridge Logic DECAY xENBL xPHASE xOUT1 xOUT2 0 0 X L L 1 0 X Z Z X 1 1 H L X 1 0 L H 7.4.2 Current Regulation The maximum current through the motor winding is regulated by a fixed-frequency PWM current regulation, or current chopping. When the H-bridge is enabled, current rises through the winding at a rate dependent on the DC voltage and inductance of the winding. Once the current hits the current chopping threshold, the bridge disables the current until the beginning of the next PWM cycle. For DC motors, current regulation is used to limit the start-up and stall current of the motor. Speed control is typically performed by providing an external PWM signal to the ENBLx input pins. If the current regulation feature is not needed, it can be disabled by connecting the xISENSE pins directly to ground, and connecting the xVREF pins to V3P3. The PWM chopping current is set by a comparator which compares the voltage across a current sense resistor connected to the xISEN pins, multiplied by a factor of 5, with a reference voltage. The reference voltage is input from the xVREF pins, and is scaled by a 2-bit DAC that allows current settings of 100%, 71%, 38% of full-scale, plus zero. The full-scale (100%) chopping current is calculated in Equation 1. VREFX ICHOP 5 u RISENSE (1) Example: If a 0.25-Ω sense resistor is used and the VREFx pin is 2.5 V, the full-scale (100%) chopping current will be 2.5 V / (5 x 0.25 Ω) = 2 A. Two input pins per H-bridge (xI1 and xI0) are used to scale the current in each bridge as a percentage of the fullscale current set by the VREF input pin and sense resistance. The function of the pins is shown in Table 2. Table 2. H-Bridge Pin Functions 10 xI1 xI0 RELATIVE CURRENT (% FULL-SCALE CHOPPING CURRENT) 1 1 0% (Bridge disabled) 1 0 38% 0 1 71% 0 0 100% Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 DRV8814 www.ti.com SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 NOTE When both xI bits are 1, the H-bridge is disabled and no current flows. Example: If a 0.25-Ω sense resistor is used and the VREF pin is 2.5 V, the chopping current will be 2 A at the 100% setting (xI1, xI0 = 00). At the 71% setting (xI1, xI0 = 01) the current will be 2 A x 0.71 = 1.42 A, and at the 38% setting (xI1, xI0 = 10) the current will be 2 A x 0.38 = 0.76 A. If (xI1, xI0 = 11) the bridge will be disabled and no current will flow. 7.4.3 Decay Mode and Braking During PWM current chopping, the H-bridge is enabled to drive current through the motor winding until the PWM current chopping threshold is reached. This is shown in Figure 6 as case 1. The current flow direction shown indicates the state when the xENBL pin is high. Once the chopping current threshold is reached, the H-bridge can operate in two different states, fast decay or slow decay. In fast decay mode, once the PWM chopping current level has been reached, the H-bridge reverses state to allow winding current to flow in a reverse direction. As the winding current approaches zero, the bridge is disabled to prevent any reverse current flow. Fast decay mode is shown in Figure 6 as case 2. In slow decay mode, winding current is re-circulated by enabling both of the low-side FETs in the bridge. This is shown in Figure 6 as case 3. Figure 6. Decay Mode The DRV8814 supports fast decay and slow decay mode. Slow or fast decay mode is selected by the state of the DECAY pin - logic low selects slow decay, and logic high sets fast decay mode. Note that the DECAY pin sets the decay mode for both H-bridges. DECAY mode also affects the operation of the bridge when it is disabled (by taking the ENBL pin inactive). This applies if the ENABLE input is being used for PWM speed control of the motor, or if it is simply being used to start and stop motor rotation. Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 11 DRV8814 SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 www.ti.com If the DECAY pin is high (fast decay), when the bridge is disabled fast decay mode will be entered until the current through the bridge reaches zero. Once the current is at zero, the bridge is disabled to prevent the motor from reversing direction. This allows the motor to coast to a stop. If the DECAY pin is low (slow decay), both low-side FETs will be turned on when ENBL is made inactive. This essentially shorts out the back EMF of the motor, causing the motor to brake, and stop quickly. The low-side FETs will stay in the ON state even after the current reaches zero. 7.4.4 Blanking Time After the current is enabled in an H-bridge, the voltage on the xISEN pin is ignored for a fixed period of time before enabling the current sense circuitry. This blanking time is fixed at 3.75 μs. Note that the blanking time also sets the minimum on time of the PWM. 7.4.5 nRESET and nSLEEP Operation The nRESET pin, when driven active low, resets the internal logic. It also disables the H-bridge drivers. All inputs are ignored while nRESET is active. Driving nSLEEP low will put the device into a low power sleep state. In this state, the H-bridges are disabled, the gate drive charge pump is stopped, the V3P3OUT regulator is disabled, and all internal clocks are stopped. In this state all inputs are ignored until nSLEEP returns inactive high. When returning from sleep mode, some time (approximately 1 ms) needs to pass before the motor driver becomes fully operational. 7.4.6 Protection Circuits The DRV8814 is fully protected against undervoltage, overcurrent and overtemperature events. 7.4.6.1 Overcurrent Protection (OCP) An analog current limit circuit on each FET limits the current through the FET by removing the gate drive. If this analog current limit persists for longer than the OCP time, all FETs in the H-bridge will be disabled and the nFAULT pin will be driven low. The device will remain disabled until either nRESET pin is applied, or VM is removed and re-applied. Overcurrent conditions on both high and low side devices; i.e., a short to ground, supply, or across the motor winding will all result in an overcurrent shutdown. Note that overcurrent protection does not use the current sense circuitry used for PWM current control, and is independent of the ISENSEresistor value or VREF voltage. 7.4.6.2 Thermal Shutdown (TSD) If the die temperature exceeds safe limits, all FETs in the H-bridge will be disabled and the nFAULT pin will be driven low. Once the die temperature has fallen to a safe level operation will automatically resume. 7.4.6.3 Undervoltage Lockout (UVLO) If at any time the voltage on the VM pins falls below the undervoltage lockout threshold voltage, all circuitry in the device will be disabled and internal logic will be reset. Operation will resume when VMrises above the UVLO threshold. 12 Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 DRV8814 www.ti.com SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 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 DRV8814 can be used to control two brushed DC motors. The PHASE/ENBL interface controls the outputs and current control can be implemented with the internal current regulation circuitry. Detailed fault reporting is provided with the internal protection circuits and nFAULT pin. 8.2 Typical Application DRV8814 CP1 GND CP2 BI1 VCP BI0 VMA AI1 AOUT1 AI0 0.01 µF 1 MΩ 0.1 µF + 0.01 µF 200 mΩ ISENA Brushed DC Motor - VM + BPHASE AOUT2 BENBL BOUT2 AENBL - 100 µF 200 mΩ Brushed DC Motor ISENB APHASE BOUT1 DECAY VMB nFAULT AVREF nSLEEP BVREF nRESET + V3P3OUT 10 kΩ 0.01 µF V3P3OUT 30 kΩ GND PPAD 10 kΩ V3P3OUT V3P3OUT 0.47 µF Figure 7. Typical Application Schematic 8.2.1 Design Requirements Specific parameters for designing a dual brushed DC motor drive system. Table 3. Design Parameters REFERENCE EXAMPLE VALUE Supply Voltage DESIGN PARAMETER VM 24 V Motor Winding Resistance RL 3.9 Ω Moto Winding Inductance IL 2.9 mH RSENSE 200 mΩ IFS 1.25 A Sense Resistor Value Target Full-Scale Current Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 13 DRV8814 SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 www.ti.com 8.2.2 Detailed Design Procedure 8.2.2.1 Current Regulation In a stepper motor, the set full-scale current (IFS) is the maximum current driven through either winding. This quantity depends on the xVREF analog voltage and the sense resistor value (RSENSE). During stepping, IFS defines the current chopping threshold (ITRIP) for the maximum current step. The gain of DRV8814 is set for 5 V/V. xVREF(V) xVREF(V) IFS (A) A v u RSENSE (:) 5 u RSENSE (:) (2) To achieve IFS = 1.25 A with RSENSE of 0.2 Ω, xVREF should be 1.25 V. 8.2.2.2 Decay Modes The DRV8814 supports two different decay modes: slow decay and fast decay. The current through the motor windings is regulated using a fixed-frequency PWM scheme. This means that after any drive phase, when a motor winding current has hit the current chopping threshold (ITRIP), the DRV8814 places the winding in one of the two decay modes until the PWM cycle has expired. Afterward, a new drive phase starts. The blanking time, tBLANK, defines the minimum drive time for the current chopping. ITRIP is ignored during tBLANK, so the winding current may overshoot the trip level. 8.2.2.3 Sense Resistor The power dissipated by the sense resistor equals Irms2 × R. For example, if the rms motor current is 2-A and a 100-mΩ sense resistor is used, the resistor dissipates 2 A2 × 0.1 Ω = 0.4 W. The power quickly increases with greater current levels. Resistors typically have a rated power within some ambient temperature range, along with a derated power curve for high ambient temperatures. When a PCB is shared with other components generating heat, margin should be added. It is always best to measure the actual sense resistor temperature in a final system, along with the power MOSFETs, as those are often the hottest components. Because power resistors are larger and more expensive than standard resistors, it is common practice to use multiple standard resistors in parallel, between the sense node and ground. This distributes the current and heat dissipation. 8.2.3 Application Curves Figure 8. Direction Change 14 Figure 9. Current Limiting Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 DRV8814 www.ti.com SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 9 Power Supply Recommendations The DRV8814 is designed to operate from an input voltage supply (VMx) range from 8 V to 45 V. Two 0.1-μF ceramic capacitors rated for VMx must be placed as close as possible to the VMA and VMB pins respectively (one on each pin). In addition to the local decoupling caps, additional bulk capacitance is required and must be sized accordingly to the application requirements. 9.1 Bulk Capacitance Bulk capacitance sizing is an important factor in motor drive system design. It is dependent on a variety of factors including: • Type of power supply • Acceptable supply voltage ripple • Parasitic inductance in the power supply wiring • Type of motor (brushed DC, brushless DC, stepper) • Motor start-up current • Motor braking method The inductance between the power supply and motor drive system limits the rate current can change from the power supply. If the local bulk capacitance is too small, the system responds to excessive current demands or dumps from the motor with a change in voltage. You should size the bulk capacitance to meet acceptable voltage ripple levels. The data sheet generally provides a recommended value but system level testing is required to determine the appropriate sized bulk capacitor. Power Supply Parasitic Wire Inductance Motor Drive System VM + ± + Motor Driver GND Local Bulk Capacitor IC Bypass Capacitor Figure 10. Setup of Motor Drive System With External Power Supply 9.2 Power Supply and Logic Sequencing There is no specific sequence for powering-up the DRV8814. It is okay for digital input signals to be present before VMx is applied. After VMx is applied to the DRV8814, it begins operation based on the status of the control pins. Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 15 DRV8814 SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 www.ti.com 10 Layout 10.1 Layout Guidelines • • • • • The VMA and VMB pins should be bypassed to GND using low-ESR ceramic bypass capacitors with a recommended value of 0.1-μF rated for VMx. This capacitor should be placed as close to the VMA and VMB pins as possible with a thick trace or ground plane connection to the device GND pin. The VMA and VMB pins must be bypassed to ground using an appropriate bulk capacitor. This component may be an electrolytic and should be located close to the DRV8814. A low-ESR ceramic capacitor must be placed in between the CPL and CPH pins. TI recommends a value of 0.01-μF rated for VMx. Place this component as close to the pins as possible. A low-ESR ceramic capacitor must be placed in between the VMA and VCP pins. TI recommends a value of 0.1-μF rated for 16 V. Place this component as close to the pins as possible. Also, place a 1-MΩ resistor between VCP and VMA. Bypass V3P3 to ground with a ceramic capacitor rated 6.3 V. Place this bypass capacitor as close to the pin as possible. 10.2 Layout Example 0.1 µF CP1 GND 0.01 µF 1 0Ÿ CP2 BI1 VCP BI0 VMA AI1 0.1 µF RISENA RISENB AOUT1 AI0 ISENA BPHASE AOUT2 BENBL BOUT2 AENBL ISENB APHASE BOUT1 DECAY VMB nFAULT + 0.1 µF AVREF nSLEEP BVREF nRESET GND V3P3OUT 0.47 µF Figure 11. DRV8814 Layout Example 10.3 Thermal Considerations 10.3.1 Thermal Protection The DRV8814 has thermal shutdown (TSD) as described in Thermal Shutdown (TSD). If the die temperature exceeds approximately 150°C, the device will be disabled until the temperature drops to a safe level. Any tendency of the device to enter TSD is an indication of either excessive power dissipation, insufficient heatsinking, or too high an ambient temperature. 16 Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 DRV8814 www.ti.com SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 Thermal Considerations (continued) 10.3.2 Power Dissipation Power dissipation in the DRV8814 is dominated by the power dissipated in the output FET resistance, or RDS(ON). Average power dissipation when running a stepper motor can be roughly estimated by Equation 3. PTOT 4 u RDS(ON) u IOUT(RMS) 2 where • • • • PTOT is the total power dissipation RDS(ON) is the resistance of each FET IOUT(RMS) is the RMS output current being applied to each winding IOUT(RMS) is equal to approximately 0.7 × the full-scale output current setting (3) The factor of 4 comes from the fact that there are two motor windings, and at any instant two FETs are conducting winding current for each winding (one high-side and one low-side). The maximum amount of power that can be dissipated in the device is dependent on ambient temperature and heatsinking. RDS(ON) increases with temperature, so as the device heats, the power dissipation increases. This must be taken into consideration when sizing the heatsink. 10.3.3 Heatsinking The PowerPAD™ package uses an exposed pad to remove heat from the device. For proper operation, this pad must be thermally connected to copper on the PCB to dissipate heat. On a multi-layer PCB with a ground plane, this can be accomplished by adding a number of vias to connect the thermal pad to the ground plane. On PCBs without internal planes, copper area can be added on either side of the PCB to dissipate heat. If the copper area is on the opposite side of the PCB from the device, thermal vias are used to transfer the heat between top and bottom layers. For details about how to design the PCB, refer to TI application report PowerPAD™ Thermally Enhanced Package, SLMA002, and TI application brief PowerPAD™ Made Easy, SLMA004, available at www.ti.com. In general, the more copper area that can be provided, the more power can be dissipated. Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 17 DRV8814 SLVSAB9E – MAY 2010 – REVISED NOVEMBER 2015 www.ti.com 11 Device and Documentation Support 11.1 Documentation Support 11.1.1 Related Documentation For related documentation see the following: • PowerPAD™ Thermally Enhanced Package, SLMA002 • PowerPAD™ Made Easy, SLMA004 11.2 Community Resources The following links connect to TI community resources. Linked contents are 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. TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support. 11.3 Trademarks PowerPAD, E2E are trademarks of Texas Instruments. All other trademarks are the property of their respective owners. 11.4 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. 11.5 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. 18 Submit Documentation Feedback Copyright © 2010–2015, Texas Instruments Incorporated Product Folder Links: DRV8814 PACKAGE OPTION ADDENDUM www.ti.com 20-Oct-2014 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (°C) Device Marking (4/5) DRV8814PWP ACTIVE HTSSOP PWP 28 50 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR -40 to 85 DRV8814 DRV8814PWPR ACTIVE HTSSOP PWP 28 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR -40 to 85 DRV8814 (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) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 20-Oct-2014 In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 20-Oct-2014 TAPE AND REEL INFORMATION *All dimensions are nominal Device DRV8814PWPR Package Package Pins Type Drawing SPQ HTSSOP 2000 PWP 28 Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 330.0 16.4 Pack Materials-Page 1 6.9 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 10.2 1.8 12.0 16.0 Q1 PACKAGE MATERIALS INFORMATION www.ti.com 20-Oct-2014 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) DRV8814PWPR HTSSOP PWP 28 2000 367.0 367.0 38.0 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. 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