SLOSE49 November   2020 DRV8434E

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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
      1. 6.5.1 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 Bridge Control
      2. 7.3.2 Current Regulation
      3. 7.3.3 Decay Modes
        1. 7.3.3.1 Mixed Decay
        2. 7.3.3.2 Fast Decay
        3. 7.3.3.3 Smart tune Dynamic Decay
        4. 7.3.3.4 Smart tune Ripple Control
        5. 7.3.3.5 Blanking time
      4. 7.3.4 Charge Pump
      5. 7.3.5 Linear Voltage Regulators
      6. 7.3.6 Logic and Quad-Level Pin Diagrams
        1. 7.3.6.1 nFAULT Pin
      7. 7.3.7 Protection Circuits
        1. 7.3.7.1 VM Undervoltage Lockout (UVLO)
        2. 7.3.7.2 VCP Undervoltage Lockout (CPUV)
        3. 7.3.7.3 Overcurrent Protection (OCP)
        4. 7.3.7.4 Thermal Shutdown (OTSD)
        5.       Fault Condition Summary
    4. 7.4 Device Functional Modes
      1. 7.4.1 Sleep Mode (nSLEEP = 0)
      2. 7.4.2 Operating Mode (nSLEEP = 1)
      3. 7.4.3 nSLEEP Reset Pulse
      4.      Functional Modes Summary
  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 Current Regulation
        2. 8.2.2.2 Power Dissipation and Thermal Calculation
      3. 8.2.3 Application Curves
    3. 8.3 Alternate Application
      1. 8.3.1 Design Requirements
      2. 8.3.2 Detailed Design Procedure
        1. 8.3.2.1 Current Regulation
        2. 8.3.2.2 Stepper Motor Speed
        3. 8.3.2.3 Decay Modes
  9. 9 Power Supply Recommendations
    1. 9.1 Bulk Capacitance
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.3 Decay Modes

During PWM current chopping, the H-bridge is enabled to drive through the motor winding until the PWM current chopping threshold is reached. This is shown in Figure 7-4, Item 1.

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. The opposite FETs are turned on; as the winding current approaches zero, the bridge is disabled to prevent any reverse current flow. Fast decay mode is shown in Figure 7-4, item 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 7-4, Item 3.

GUID-8D174A03-C921-4B69-B22A-C2364E4B4593-low.gifFigure 7-4 Decay Modes

The decay mode is selected by setting the quad-level ADECAY and BDECAY pins as shown in Table 7-5.

Table 7-5 Decay Mode Settings
xDECAY DECAY MODE
0 Smart tune Dynamic Decay
1 Smart tune Ripple Control
Hi-Z Mixed decay: 30% fast
330k to GND Fast decay

The ADECAY pin sets the decay mode for H-bridge A (AOUT1, AOUT2), and the BDECAY pin sets the decay mode for H-bridge B (BOUT1, BOUT2).