JAJSKV6D August   2020  – April 2024 DRV8714-Q1 , DRV8718-Q1

PRODMIX  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
    1. 5.1 VQFN (RVJ) 56-Pin Package and Pin Functions
    2. 5.2 VQFN (RHA) 40-Pin Package and Pin Functions
    3. 5.3 HTQFP (PHP) 48-Pin Package and Pin Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Timing Diagrams
    8. 6.8 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 External Components
      2. 7.3.2 Device Interface Variants
        1. 7.3.2.1 Serial Peripheral Interface (SPI)
        2. 7.3.2.2 Hardware (H/W)
      3. 7.3.3 Input PWM Control Modes
        1. 7.3.3.1 Half-Bridge Control Scheme With Input PWM Mapping
          1. 7.3.3.1.1 DRV8718-Q1 Half-Bridge Control
          2. 7.3.3.1.2 DRV8714-Q1 Half-Bridge Control
        2. 7.3.3.2 H-Bridge Control
          1. 7.3.3.2.1 DRV8714-Q1 H-Bridge Control
        3. 7.3.3.3 Split HS and LS Solenoid Control
          1. 7.3.3.3.1 DRV8714-Q1 Split HS and LS Solenoid Control
      4. 7.3.4 Smart Gate Driver
        1. 7.3.4.1 Functional Block Diagram
        2. 7.3.4.2 Slew Rate Control (IDRIVE)
        3. 7.3.4.3 Gate Drive State Machine (TDRIVE)
        4. 7.3.4.4 Propagation Delay Reduction (PDR)
          1. 7.3.4.4.1 PDR Pre-Charge/Pre-Discharge Control Loop Operation Details
            1. 7.3.4.4.1.1 PDR Pre-Charge/Pre-Discharge Setup
          2. 7.3.4.4.2 PDR Post-Charge/Post-Discharge Control Loop Operation Details
            1. 7.3.4.4.2.1 PDR Post-Charge/Post-Discharge Setup
          3. 7.3.4.4.3 Detecting Drive and Freewheel MOSFET
        5. 7.3.4.5 Automatic Duty Cycle Compensation (DCC)
        6. 7.3.4.6 Closed Loop Slew Time Control (STC)
          1. 7.3.4.6.1 STC Control Loop Setup
      5. 7.3.5 Tripler (Dual-Stage) Charge Pump
      6. 7.3.6 Wide Common-Mode Current Shunt Amplifiers
      7. 7.3.7 Pin Diagrams
        1. 7.3.7.1 Logic Level Input Pin (INx/ENx, INx/PHx, nSLEEP, nSCS, SCLK, SDI)
        2. 7.3.7.2 Logic Level Push Pull Output (SDO)
        3. 7.3.7.3 Logic Level Multi-Function Pin (DRVOFF/nFLT)
        4. 7.3.7.4 Quad-Level Input (GAIN, MODE)
        5. 7.3.7.5 Six-Level Input (IDRIVE, VDS)
      8. 7.3.8 Protection and Diagnostics
        1. 7.3.8.1  Gate Driver Disable (DRVOFF/nFLT and EN_DRV)
        2. 7.3.8.2  Low IQ Powered Off Braking (POB, BRAKE)
        3. 7.3.8.3  Fault Reset (CLR_FLT)
        4. 7.3.8.4  DVDD Logic Supply Power on Reset (DVDD_POR)
        5. 7.3.8.5  PVDD Supply Undervoltage Monitor (PVDD_UV)
        6. 7.3.8.6  PVDD Supply Overvoltage Monitor (PVDD_OV)
        7. 7.3.8.7  VCP Charge Pump Undervoltage Lockout (VCP_UV)
        8. 7.3.8.8  MOSFET VDS Overcurrent Protection (VDS_OCP)
        9. 7.3.8.9  Gate Driver Fault (VGS_GDF)
        10. 7.3.8.10 Thermal Warning (OTW)
        11. 7.3.8.11 Thermal Shutdown (OTSD)
        12. 7.3.8.12 Offline Short Circuit and Open Load Detection (OOL and OSC)
        13. 7.3.8.13 Watchdog Timer
        14. 7.3.8.14 Fault Detection and Response Summary Table
    4. 7.4 Device Functional Modes
      1. 7.4.1 Inactive or Sleep State
      2. 7.4.2 Standby State
      3. 7.4.3 Operating State
    5. 7.5 Programming
      1. 7.5.1 SPI Interface
      2. 7.5.2 SPI Format
      3. 7.5.3 SPI Interface for Multiple Slaves
        1. 7.5.3.1 SPI Interface for Multiple Slaves in Daisy Chain
  9. 8 Register Maps
    1. 8.1 DRV8718-Q1 Register Map
    2. 8.2 DRV8714-Q1 Register Map
    3. 8.3 DRV8718-Q1 Register Descriptions
      1. 8.3.1 DRV8718-Q1_STATUS Registers
      2. 8.3.2 DRV8718-Q1_CONTROL Registers
      3. 8.3.3 DRV8718-Q1_CONTROL_ADV Registers
      4. 8.3.4 DRV8718-Q1_STATUS_ADV Registers
    4. 8.4 DRV8714-Q1 Register Descriptions
      1. 8.4.1 DRV8714-Q1_STATUS Registers
      2. 8.4.2 DRV8714-Q1_CONTROL Registers
      3. 8.4.3 DRV8714-Q1_CONTROL_ADV Registers
      4. 8.4.4 DRV8714-Q1_STATUS_ADV Registers
  10. 9  Application Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Gate Driver Configuration
          1. 9.2.2.1.1 VCP Load Calculation Example
          2. 9.2.2.1.2 IDRIVE Calculation Example
          3. 9.2.2.1.3 tDRIVE Calculation Example
          4. 9.2.2.1.4 Maximum PWM Switching Frequency
        2. 9.2.2.2 Current Shunt Amplifier Configuration
        3. 9.2.2.3 Power Dissipation
      3. 9.2.3 Application Curves
    3. 9.3 Initialization
    4. 9.4 Power Supply Recommendations
      1. 9.4.1 Bulk Capacitance Sizing
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
  11. 10Device Documentation and Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documents
    2. 10.2 ドキュメントの更新通知を受け取る方法
    3. 10.3 サポート・リソース
    4. 10.4 Trademarks
    5. 10.5 静電気放電に関する注意事項
    6. 10.6 用語集
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Package Option Addendum

9.2.2.2 Current Shunt Amplifier Configuration

The DRV871x-Q1 differential shunt amplifier gain and shunt resistor value are selected based on the dynamic current range, reference voltage supply, shunt resistor power rating, and operating temperature range. In bidirectional operation of the shunt amplifier, the dynamic range at the output is approximately calculated as shown in Equation 11. The output of the amplifier can swing from the midpoint reference (VAREF / 2) to either 0.25 V or VAREF - 0.25V depending on the polarity of the input voltage to the amplifier.

Equation 11. VSO_BI = (VAREF - 0.25 V) - (VAREF / 2)

If only unidirectional current sensing is required, the amplifier reference can be modified to expand the dynamic range at the output. The is modified through the CSA_DIV SPI register setting. In this mode, the dynamic range at the output is approximately calculated as shown in Equation 12.

Equation 12. VSO_UNI = (VAREF - 0.25 V) - (VAREF / 8)

Based on VAREF = 3.3 V, the dynamic out range in both bidirectional or unidirectional sensing can be calculated as shown below:

Equation 13. VSO_BI = (3.3 V - 0.25 V) - (3.3 V / 2) = 1.4 V
Equation 14. VSO_UNI = (3.3 V - 0.25 V) - (3.3 V / 8) = 2.6375 V

The external shunt resistor value and shunt amplifier gain setting are selected based on the available dynamic output range, the shunt resistor power rating, and maximum motor current that needs to be measured. This exact values for the shunt resistance and amplifier gain are determine by both Equation 15 and Equation 16.

Equation 15. RSHUNT < PSHUNT / IMAX2
Equation 16. AV < VSO / (IMAX x RSHUNT)

Based on VSO = 1.4 V, IMAX = 25 A and PSHUNT = 3 W, the values for shunt resistance and amplifier gain can be calculated as shown below:

Equation 17. RSHUNT < 3 W / 252 A = 4.8 mΩ
Equation 18. AV < 1.4 V / (25 A x 4.8 mΩ) = 11.67 V/V

Based on the results, a shunt resistance of 4 mΩ and an amplifier gain of 10 V/V can be selected.