JAJSR89 August   2024 AMC0106M25

ADVANCE INFORMATION  

  1.   1
  2. 特長
  3. アプリケーション
  4. 概要
  5. Pin Configuration and Functions
  6. Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information (DEN Package)
    5. 5.5 Package Characteristics
    6. 5.6 Electrical Characteristics
    7. 5.7 Switching Characteristics
    8. 5.8 Timing Diagrams
  7. Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Analog Input
      2. 6.3.2 Modulator
      3. 6.3.3 Isolation Channel Signal Transmission
      4. 6.3.4 Digital Output
        1. 6.3.4.1 Output Behavior in Case of a Full-Scale Input
        2. 6.3.4.2 Output Behavior in Case of a Missing High-Side Supply
    4. 6.4 Device Functional Modes
  8. Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Shunt Resistor Sizing
        2. 7.2.2.2 Input Filter Design
        3. 7.2.2.3 Bitstream Filtering
        4. 7.2.2.4 Designing the Bootstrap Supply
    3. 7.3 Best Design Practices
    4. 7.4 Power Supply Recommendations
    5. 7.5 Layout
      1. 7.5.1 Layout Guidelines
      2. 7.5.2 Layout Example
  9. Device and Documentation Support
    1. 8.1 Documentation Support
      1. 8.1.1 Related Documentation
    2. 8.2 ドキュメントの更新通知を受け取る方法
    3. 8.3 サポート・リソース
    4. 8.4 Trademarks
    5. 8.5 静電気放電に関する注意事項
    6. 8.6 用語集
  10. Revision History
  11. 10Mechanical, Packaging, and Orderable Information
    1. 10.1 Mechanical Data

Bitstream Filtering

The modulator generates a bitstream that is processed by a digital filter to obtain a digital word similar to a conversion result of a conventional analog-to-digital converter (ADC). Equation 2 shows a sinc3-type filter, which is a very simple filter built with minimal effort and hardware.

 

Equation 2. AMC0106M25

This filter provides the best output performance at the lowest hardware size (count of digital gates) for a second-order modulator. All characterization in this document is done with a sinc3 filter with an oversampling ratio (OSR) of 256 and a 16-bit output word width.

The Combining the ADS1202 with an FPGA Digital Filter for Current Measurement in Motor Control Applications application note discusses an example code. Use this example code for implementing a sinc3 filter in an FPGA. This application note is available for download at www.ti.com.

For modulator output bitstream filtering, use a device from TI's C2000 or Sitara microcontroller families. These families support multichannel dedicated hardwired filter structures that significantly simplify system level design by offering two filtering paths per channel. One path provides high-accuracy results for the control loop and the other provides a fast-response path for overcurrent detection.

A delta sigma modulator filter calculator is available for download at www.ti.com that aids in filter design and correct OSR and filter order selection. This calculator helps achieve the desired output resolution and filter response time.