ZHCSND1A November   2020  – May 2022 DRV8434

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1. 5.1 引脚功能
  6. 6 规格
    1. 6.1 绝对最大额定值
    2. 6.2 ESD 等级
    3. 6.3 建议运行条件
    4. 6.4 热性能信息
    5. 6.5 Electrical Characteristics
    6. 6.6 Indexer Timing Requirements
      1. 6.6.1 典型特性
  7. 7 详细说明
    1. 7.1 概述
    2. 7.2 功能模块图
    3. 7.3 特性说明
      1. 7.3.1  Stepper Motor Driver Current Ratings
        1. 7.3.1.1 峰值电流额定值
        2. 7.3.1.2 均方根电流额定值
        3. 7.3.1.3 Full-Scale Current Rating
      2. 7.3.2  PWM Motor Drivers
      3. 7.3.3  Microstepping Indexer
      4. 7.3.4  Controlling VREF with an MCU DAC
      5. 7.3.5  电流调节
      6. 7.3.6  Decay Modes
        1. 7.3.6.1 Slow Decay for Increasing and Decreasing Current
        2. 7.3.6.2 Slow Decay for Increasing Current, Mixed Decay for Decreasing Current
        3. 7.3.6.3 上升和下降电流阶段均为混合衰减
        4. 7.3.6.4 Smart tune Dynamic Decay
        5. 7.3.6.5 智能调优纹波控制
        6. 7.3.6.6 PWM 关断时间
        7. 7.3.6.7 消隐时间
      7. 7.3.7  电荷泵
      8. 7.3.8  线性稳压器
      9. 7.3.9  Logic Level, Tri-Level and Quad-Level Pin Diagrams
        1. 7.3.9.1 nFAULT 引脚
      10. 7.3.10 保护电路
        1. 7.3.10.1 VM 欠压锁定 (UVLO)
        2. 7.3.10.2 VCP 欠压锁定 (CPUV)
        3. 7.3.10.3 过流保护 (OCP)
          1. 7.3.10.3.1 锁存关断
          2. 7.3.10.3.2 自动重试
        4. 7.3.10.4 开路负载检测 (OL)
        5. 7.3.10.5 热关断 (OTSD)
          1. 7.3.10.5.1 锁存关断
          2. 7.3.10.5.2 自动重试
        6.       Fault Condition Summary
    4. 7.4 器件功能模式
      1. 7.4.1 睡眠模式 (nSLEEP = 0)
      2.      52
      3. 7.4.2 禁用模式（nSLEEP = 1，ENABLE = 0）
      4. 7.4.3 工作模式（nSLEEP = 1，ENABLE = Hi-Z/1）
      5. 7.4.4 nSLEEP 复位脉冲
      6.      功能模式汇总
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Stepper Motor Speed
        2. 8.2.2.2 电流调节
        3. 8.2.2.3 衰减模式
        4. 8.2.2.4 应用曲线
        5. 8.2.2.5 Thermal Application
          1. 8.2.2.5.1 Power Dissipation
          2. 8.2.2.5.2 Conduction Loss
          3. 8.2.2.5.3 Switching Loss
          4. 8.2.2.5.4 Power Dissipation Due to Quiescent Current
          5. 8.2.2.5.5 Total Power Dissipation
          6. 8.2.2.5.6 Device Junction Temperature Estimation
  9. 9 Power Supply Recommendations
    1. 9.1 大容量电容
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Related Documentation
    2. 11.2 接收文档更新通知
    3. 11.3 支持资源
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 术语表
  12. 12Mechanical, Packaging, and Orderable Information

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息
8.2.2.5.3 Switching Loss

The power loss due to the PWM switching frequency depends on the slew rate (tSR), supply voltage, motor RMS current and the PWM switching frequency. The switching losses in each H-bridge during rise-time and fall-time are calculated as shown in Equation 5 and Equation 6.

Equation 5. PSW_RISE = 0.5 x VVM x IRMS x tRISE_PWM x fPWM
Equation 6. PSW_FALL = 0.5 x VVM x IRMS x tFALL_PWM x fPWM

Both tRISE_PWM and tFALL_PWM can be approximated as VVM/ tSR. After substituting the values of various parameters, and assuming 30-kHz PWM frequency, the switching losses in each H-bridge are calculated as shown below -

Equation 7. PSW_RISE = 0.5 x 24-V x (2-A / √2) x (24-V / 240 V/µs) x 30-kHz = 0.05-W
Equation 8. PSW_FALL = 0.5 x 24-V x (1-A / √2) x (24-V / 240 V/µs) x 30-kHz = 0.05-W

The total switching loss for the stepper motor driver (PSW) is calculated as twice the sum of rise-time (PSW_RISE) switching loss and fall-time (PSW_FALL) switching loss as shown below -

Equation 9. PSW = 2 x (PSW_RISE + PSW_FALL) = 2 x (0.05-W + 0.05-W) = 0.2-W
Note:

The rise-time (tRISE) and the fall-time (tFALL) are calculated based on typical values of the slew rate (tSR). This parameter is expected to change based on the supply-voltage, temperature and device to device variation.

The switching loss is directly proportional to the PWM switching frequency. The PWM frequency in an application will depend on the supply voltage, inductance of the motor coil, back emf voltage and OFF time or the ripple current (for smart tune ripple control decay mode).