SLOSE83 March   2023 DRV8952

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1  Overview
    2. 7.2  Functional Block Diagram
    3. 7.3  Feature Description
    4. 7.4  Independent Half-bridge Operation
    5. 7.5  Current Sensing and Regulation
      1. 7.5.1 Current Sensing and Feedback
      2. 7.5.2 Current Sensing with External Resistor
      3. 7.5.3 Current Regulation
    6. 7.6  Charge Pump
    7. 7.7  Linear Voltage Regulator
    8. 7.8  VCC Voltage Supply
    9. 7.9  Logic Level Pin Diagram
    10. 7.10 Protection Circuits
      1. 7.10.1 VM Undervoltage Lockout (UVLO)
      2. 7.10.2 VCP Undervoltage Lockout (CPUV)
      3. 7.10.3 Logic Supply Power on Reset (POR)
      4. 7.10.4 Overcurrent Protection (OCP)
      5. 7.10.5 Thermal Shutdown (OTSD)
      6. 7.10.6 nFAULT Output
      7. 7.10.7 Fault Condition Summary
    11. 7.11 Device Functional Modes
      1. 7.11.1 Sleep Mode (nSLEEP = 0)
      2. 7.11.2 Operating Mode
      3. 7.11.3 nSLEEP Reset Pulse
      4. 7.11.4 Functional Modes Summary
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Driving Solenoid Loads
        1. 8.1.1.1 Solenoid Driver Typical Application
        2. 8.1.1.2 Thermal Calculations
          1. 8.1.1.2.1 Power Loss Calculations
          2. 8.1.1.2.2 Junction Temperature Estimation
        3. 8.1.1.3 Application Performance Plots
      2. 8.1.2 Driving Stepper Motors
        1. 8.1.2.1 Stepper Driver Typical Application
        2. 8.1.2.2 Power Loss Calculations
        3. 8.1.2.3 Junction Temperature Estimation
      3. 8.1.3 Driving Brushed-DC Motors
        1. 8.1.3.1 Brushed-DC Driver Typical Application
        2. 8.1.3.2 Power Loss Calculation
        3. 8.1.3.3 Junction Temperature Estimation
        4. 8.1.3.4 Driving Single Brushed-DC Motor
      4. 8.1.4 Driving Thermoelectric Coolers (TEC)
      5. 8.1.5 Driving Brushless DC Motors
  9. 9 Package Thermal Considerations
    1. 9.1 DDW Package
      1. 9.1.1 Thermal Performance
        1. 9.1.1.1 Steady-State Thermal Performance
        2. 9.1.1.2 Transient Thermal Performance
  10. 10Power Supply Recommendations
    1. 10.1 Bulk Capacitance
    2. 10.2 Power Supplies
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 PCB Material Recommendation
    3. 11.3 Thermal Considerations
  12. 12Device and Documentation Support
    1. 12.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information
    1. 13.1 Tape and Reel Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.1.2.2 Power Loss Calculations

The following calculations assume a use case where the supply voltage is 24 V, full-scale current is 5 A, rise/fall time is 140 ns and input PWM frequency is 30-kHz.

The total power dissipation constitutes of three main components - conduction loss (PCOND), switching loss (PSW) and power loss due to quiescent current consumption (PQ).

The conduction loss (PCOND) depends on the motor rms current (IRMS) and high-side (RDS(ONH)) and low-side (RDS(ONL)) on-state resistances as shown in Equation 8.

Equation 8. PCOND = 2 x (IRMS)2 x (RDS(ONH) + RDS(ONL))

The conduction loss for the typical application shown in Section 8.1.2.1 is calculated in Equation 9.

Equation 9. PCOND = 2 x (IRMS)2 x (RDS(ONH) + RDS(ONL)) = 2 x (5-A / √2)2 x (0.112-Ω) = 2.8-W

The power loss due to the PWM switching frequency depends on the output voltage rise/fall time (tRF), 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 10 and Equation 11.

Equation 10. PSW_RISE = 0.5 x VVM x IRMS x tRF x fPWM
Equation 11. PSW_FALL = 0.5 x VVM x IRMS x tRF x fPWM

After substituting the values of various parameters, the switching losses in each H-bridge are calculated as shown below -

Equation 12. PSW_RISE = 0.5 x 24-V x (5-A / √2) x (140 ns) x 30-kHz = 0.178-W
Equation 13. PSW_FALL = 0.5 x 24-V x (5-A / √2) x (100 ns) x 30-kHz = 0.178-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 14. PSW = 2 x (PSW_RISE + PSW_FALL) = 2 x (0.178-W + 0.178-W) = 0.712-W
Note:

The output rise/fall time (tRF) is expected to change based on the supply-voltage, temperature and device to device variation.

When the VCC pin is connected to an external voltage, the quiescent current is typically 4 mA. The power dissipation due to the quiescent current consumed by the power supply is calculated as shown below -

Equation 15. PQ = VVM x IVM

Substituting the values, quiescent power loss can be calculated as shown below -

Equation 16. PQ = 24-V x 4-mA = 0.096-W
Note:

The quiescent power loss is calculated using the typical operating supply current (IVM) which is dependent on supply-voltage, temperature and device to device variations.

The total power dissipation (PTOT) is calculated as the sum of conduction loss, switching loss and the quiescent power loss as shown in Equation 17.

Equation 17. PTOT = PCOND + PSW + PQ = 2.8-W + 0.712-W + 0.096-W = 3.608-W