ZHCSPK0 July   2022 ISOW7721

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 说明（续）
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Power Ratings
    6. 7.6  Insulation Specifications
    7. 7.7  Safety-Related Certifications
    8. 7.8  Safety Limiting Values
    9. 7.9  Electrical Characteristics - Power Converter
    10. 7.10 Supply Current Characteristics - Power Converter
    11. 7.11 Electrical Characteristics Channel Isolator - VIO, VISOIN = 5-V
    12. 7.12 Supply Current Characteristics Channel Isolator - VIO, VISOIN = 5-V
    13. 7.13 Electrical Characteristics Channel Isolator - VIO, VISOIN = 3.3-V
    14. 7.14 Supply Current Characteristics Channel Isolator - VIO, VISOIN = 3.3-V
    15. 7.15 Electrical Characteristics Channel Isolator - VIO, VISOIN = 2.5-V
    16. 7.16 Supply Current Characteristics Channel Isolator - VIO, VISOIN = 2.5-V
    17. 7.17 Electrical Characteristics Channel Isolator - VIO, VISOIN = 1.8-V
    18. 7.18 Supply Current Characteristics Channel Isolator - VIO, VISOIN = 1.8-V
    19. 7.19 Switching Characteristics - 5-V Supply
    20. 7.20 Switching Characteristics - 3.3-V Supply
    21. 7.21 Switching Characteristics - 2.5-V Supply
    22. 7.22 Switching Characteristics - 1.8-V Supply
    23. 7.23 Insulation Characteristics Curves
    24. 7.24 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
      1. 9.1.1 Power Isolation
      2. 9.1.2 Signal Isolation
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Electromagnetic Compatibility (EMC) Considerations
      2. 9.3.2 Power-Up and Power-Down Behavior
      3. 9.3.3 Protection Features
      4. 9.3.4 Multi-Device Chaining for Increased Power Output
    4. 9.4 Device Functional Modes
      1. 9.4.1 Device I/O Schematics
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curve
      4. 10.2.4 Insulation Lifetime
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 PCB Material
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Development Support
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 支持资源
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 术语表
  14. 14Mechanical, Packaging, and Orderable Information

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9.3.4 Multi-Device Chaining for Increased Power Output

The ISOW7721 supports daisy chaining multiple ISOW7721 devices to achive > 110 mA load as shown in Figure 9-4. The below equation provides an estimate for the required number of ISOW7721 devices to meet a target load current.

N u m b e r   o f   d e v i c e = c e i l T a r g e t   l o a d   c u r r e n t - M a x i u m u m   a v a i l a b l e   l o a d   c u r r e n t 0.8   M a x i u m u m   a v a i l a b l e   l o a d   c u r r e n t + 1

Example:

Design a multi-device chaning using ISOW7721 to drive a 680 mA load for VDD = 5 V and VSEL = 5 V.

The Maximum avaialble load current for VDD = 5 V, and VSEL = 5 V is 100 mA from page 1.

N u m b e r   o f   d e v i c e = c e i l 680 - 110 0.8   ( 110 ) + 1 = 8

From the above calculation, we need 8 ISOW7721 to drive a 680 mA load.

Follow the procedures below to configure multi-device chaining.

  1. Set LF to GND1 to make a device as the leader of the daisy chain (only one leader is allowed in a daisy chain). The CC pin of the leader is configured as an output
  2. Set LF to VDD to make the other device as a follower (may use more than one follower to meet your system current requirement). The CC pin of the follower is configured as an input.
  3. A voltage change on the LF pin requires a power cycling to put the device into the desired role. Please ensure that all devices are powered during multi-device chaining operation to prevent the VISOOUT pin of an unpowered device from exposing to an overvoltage condition. An unpowered device can cause the VSEL to set to GND and thus the maximum rating for its VISOOUT is 4 V. Device damage is possible if this VISOOUT pin is driven by another 5 V VISOOUT pin for an extensive long time.
  4. Connect the CC pin of the leader to the CC pin of the follower (may use more than one follower) and this will allow the leader to synchronize with the follower.
  5. Connect all the VISOOUT pins and VISOIN pins together for the leader and the follower(s).
  6. Connect all the GISOUT pins together for the leader and the follower(s).
  7. Connect all the VDD pins together for the leader and the follower(s).
  8. All the VSEL pins should be set to the same logic state.

Figure 9-4 Multi-Device Chaining