ZHCSKL1A December   2019  – May 2022 TUSS4440

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  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  Power-Up Characteristics
    6. 6.6  Transducer Drive
    7. 6.7  Receiver Characteristics
    8. 6.8  Echo Interrupt Comparator Characteristics
    9. 6.9  Digital I/O Characteristics
    10. 6.10 Switching Characteristics
    11. 6.11 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Excitation Power Supply (VDRV)
      2. 7.3.2 Burst Generation
        1. 7.3.2.1 Burst Generation Diagnostics
      3. 7.3.3 Transformer Transducer Drive
      4. 7.3.4 Analog Front End
    4. 7.4 Device Functional Modes
    5. 7.5 Programming
    6. 7.6 Register Maps
      1. 7.6.1 REG_USER Registers
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Transformer Drive Configuration Options
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Transducer Driving Voltage
          2. 8.2.1.2.2 Transducer Driving Frequency
          3. 8.2.1.2.3 Transducer Pulse Count
          4. 8.2.1.2.4 Transformer Turns Ratio
          5. 8.2.1.2.5 Transformer Saturation Current and Main Voltage Rating
        3. 8.2.1.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 接收文档更新通知
    2. 11.2 支持资源
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 术语表
  12. 12Mechanical, Packaging, and Orderable Information

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8.2.1.2.4 Transformer Turns Ratio

A center-tap transformer is typically paired with the transducer to convert a DC voltage to a high-sinusoidal AC voltage. The center tap is a contact made to a point halfway along the primary winding of the transformer. The center tap is supplied with the DC voltage that is then multiplied on the secondary side based on the turns ratio of the transformer. Figure 8-4 shows the typical pinout of a center-tap transformer where pin 2 is the center tap, pins 1 and 3 are connected to OUTB and OUTA, pin 4 is connected to the positive terminal of the transducer, and pin 6 is connected to ground.

GUID-17C34EBD-A3F5-43F3-BD38-A3731A942D19-low.gifFigure 8-4 Typical Pinout of Center-Tap Transformer for Ultrasonic Transducers

Two modes to generate the transducer voltage using the center-tap transformer are available. These modes are defined as follows:

    Push-pullIn this mode, the two internal low-side switches of the TUSS4440 device are used to turn current on and off in two primary coils of the center-tap transformer.

    The primary coils have the same number of turns. The rate of change of current in the primary coil generates a voltage in the secondary coil of the transformer, which is connected to the transducer. The direction of current in the primary coils generates voltages of opposite polarity in the secondary coils which effectively doubles the peak-to-peak voltage in the secondary coil.

    Single-endedIn this mode, one low-side switch is used to turn current on and off in the primary of the transformer.

    The rate of change of current in the primary coil generates a voltage in the secondary coil of the transformer, which is connected to the transducer. The center tap of the transformer is not required for this mode, and can be left floating. Instead, the reference voltage is connected to an outermost primary-side terminal (pin 3) and either OUTA or OUTB is connected to the other primary-side terminal (pin 1).