SLVSGS5A December   2023  – June 2024 DRV3946-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 SPI Timing Requirements
    7. 5.7 Timing Diagrams
    8. 5.8 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  Recommended External Components
      2. 6.3.2  Power Supplies and Monitors
        1. 6.3.2.1 PVDD and VDD Power Supplies
        2. 6.3.2.2 PVDD Monitor
        3. 6.3.2.3 VDD Monitor
        4. 6.3.2.4 RESET (nPOR)
        5. 6.3.2.5 Device Safety Layer
      3. 6.3.3  Output Driver
        1. 6.3.3.1 Retry Wait
        2. 6.3.3.2 Over Current Protection
        3. 6.3.3.3 Thermal Protection
      4. 6.3.4  Start-up Sequencing
      5. 6.3.5  Current Control
        1. 6.3.5.1 Internal Regulation Mode
          1. 6.3.5.1.1 Current Thresholds
          2. 6.3.5.1.2 PWM Cycle Control
        2. 6.3.5.2 Fixed Frequency, Variable Duty Cycle Mode
        3. 6.3.5.3 Fixed Duty Cycle, Variable Frequency Mode
        4. 6.3.5.4 Quick Turn Off
        5. 6.3.5.5 PWM Frequency
        6. 6.3.5.6 Minimum and Maximum Duty Cycle
      6. 6.3.6  EN/EN1 and DIS/EN2 pins
      7. 6.3.7  Diagnostics Features
        1. 6.3.7.1 On State Diagnostics
          1. 6.3.7.1.1 PWM Cycle Warnings
          2. 6.3.7.1.2 Timer Based Warnings
        2. 6.3.7.2 Off-state Diagnostics
      8. 6.3.8  nFAULT/NAD Pin
      9. 6.3.9  Fault Table
      10. 6.3.10 Programming
        1. 6.3.10.1 SPI Interface
        2. 6.3.10.2 Addressable SPI
        3. 6.3.10.3 SPI Error Indicators
        4. 6.3.10.4 SPI Format
        5. 6.3.10.5 SPI Watchdog Monitor
  8. 7 Register Maps
    1. 7.1 STATUS Registers
      1. 7.1.1 STATUS0 Register (Address = 1h) [Reset = 2500h]
      2. 7.1.2 STATUS1 Register (Address = 2h) [Reset = 0803h]
      3. 7.1.3 STATUS2 Register (Address = 3h) [Reset = 0000h]
      4. 7.1.4 STATUS3 Register (Address = 4h) [Reset = 0000h]
      5. 7.1.5 STATUS4 Register (Address = Ah) [Reset = 0000h]
      6. 7.1.6 STATUS5 Register (Address = Bh) [Reset = 0000h]
    2. 7.2 MEAS Registers
      1. 7.2.1 MEAS0 Register (Address = 5h) [Reset = 0000h]
      2. 7.2.2 MEAS1 Register (Address = 6h) [Reset = 0000h]
      3. 7.2.3 MEAS2 Register (Address = 7h) [Reset = 0000h]
      4. 7.2.4 MEAS3 Register (Address = 8h) [Reset = 0000h]
      5. 7.2.5 MEAS4 Register (Address = 9h) [Reset = 0000h]
      6. 7.2.6 MEAS5 Register (Address = Ch) [Reset = 0000h]
      7. 7.2.7 MEAS6 Register (Address = Dh) [Reset = 0000h]
    3. 7.3 CONFIG A Registers
      1. 7.3.1 CONFIG_A0 Register (Address = 10h) [Reset = C040h]
      2. 7.3.2 CONFIG_A1 Register (Address = 11h) [Reset = C040h]
      3. 7.3.3 CONFIG_A2 Register (Address = 12h) [Reset = 2424h]
      4. 7.3.4 CONFIG_A3 Register (Address = 13h) [Reset = 0088h]
      5. 7.3.5 CONFIG_A4 Register (Address = 14h) [Reset = 130Ch]
      6. 7.3.6 CONFIG_A5 Register (Address = 15h) [Reset = 8000h]
      7. 7.3.7 CONFIG_A6 Register (Address = 16h) [Reset = 0000h]
    4. 7.4 CONFIG B Registers
      1. 7.4.1 CONFIG_B0 Register (Address = 17h) [Reset = 2623h]
      2. 7.4.2 CONFIG_B1 Register (Address = 18h) [Reset = 0040h]
      3. 7.4.3 CONFIG_B2 Register (Address = 19h) [Reset = 0B0Bh]
      4. 7.4.4 CONFIG_B3 Register (Address = 1Ah) [Reset = 8000h]
      5. 7.4.5 CONFIG_B4 Register (Address = 1Bh) [Reset = 0000h]
    5. 7.5 CMD Registers
      1. 7.5.1 CMD0 Register (Address = 1Ch) [Reset = 8000h]
      2. 7.5.2 CMD1 Register (Address = 1Dh) [Reset = 0000h]
      3. 7.5.3 CMD2 Register (Address = 1Eh) [Reset = 0000h]
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Transient Thermal Impedance and Current Capability
      3. 8.2.3 Application Performance Plots
      4. 8.2.4 PVDD Capacitance Value Estimation
    3. 8.3 Initialization Setup
      1. 8.3.1 Device Initialization – NAD
      2. 8.3.2 Device Initialization – Configuration
      3. 8.3.3 System Initialization
        1. 8.3.3.1 EN/EN1 and DIS/EN2 Function Check
        2. 8.3.3.2 nFAULT Signalling Check
        3. 8.3.3.3 Device Timing Check
        4. 8.3.3.4 Secondary Logic Check
      4. 8.3.4 Turn On Relay
      5. 8.3.5 Turn Off Relay
        1. 8.3.5.1 Using Target Device Command
        2. 8.3.5.2 Using Broadcast Command
    4. 8.4 Power Supply Recommendations
      1. 8.4.1 PVDD Supply Requirements
      2. 8.4.2 PVDD Undervoltage Transients - Contactor Chatter or Weld Prevention
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Package Option Addendum
    2. 11.2 Tape and Reel Information

3 Description

The DRV3946-Q1 is a highly integrated solution to drive two solenoids for automotive applications such as contactor relays in EV battery management systems. It includes power supplies, current sensing and current regulation, configurable peak and hold currents and associated timings, and diagnostics and protection functions. It also incorporates several unique functions that enhance performance compared to traditional discrete solenoid drivers. These functions include integrated redundant clamp circuits to quickly discharge the load current, an addressable SPI, and modified half-bridge driver stage with low on-resistance switches.

The device controls solenoid loads through a single wire low-side connection and can pair with an external high-side switch (that can be shared) for redundant shut-off function. Integrated switches perform charging, recirculation and clamping. The device supports internal and external current control modes. The PWM frequency is configurable, with added low frequency dithering using automatic pseudo random frequencies generation and wave shaping. Internal PWM current control loop leads to reduced software development, since MCU current control loop is not needed. The DRV3946-Q1 supports flexible current control parameters to support wide range of solenoid types. Configurable peak and hold current and corresponding timing parameters allow system level power saving.

The DRV3946-Q1 is targeted to be functional safety-compliant, with ASIL-C rated functional safety goal for relay control and avoiding unintended operation. The device supports comprehensive protection and diagnostic features, such as continuous monitoring of load for open and short detection, on and off-state diagnostics, voltage monitors, short protection and high voltage rated IOs.

An addressable SPI allows multiple devices to be controlled on a shared SPI bus. In addition to reducing required MCU resources, the addressable SPI incorporates a broadcast command structure that can enable all devices on the shared addressed bus to take certain actions simultaneously. The SPI incorporates multiple robustness functions including a CRC, address readback capability, and various bus fault detection mechanisms.

DRV3946-Q1 Simplified Schematic Simplified Schematic