ZHCU763 March   2021

 

  1.   说明
  2.   资源
  3.   特性
  4.   应用
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Multichannel SSR with Independent Isolation Between SSR Channels
      2. 2.2.2 Design Challenge With Single Isolation
      3. 2.2.3 Multichannel SSR Drive With Single Isolation Multichannel Digital Isolator
      4. 2.2.4 Need of High-Impedance Voltage Translator
      5. 2.2.5 Design to Minimize Cross-Coupling and MOSFET Gate Pick up Due to Other SSR Switching
      6. 2.2.6 Schematic: Design of Gate-Drive Circuit
        1. 2.2.6.1 Calculation of Gate-Driver Power Consumption
      7. 2.2.7 Schematic: Digital Isolator Circuit
      8. 2.2.8 Schematic: 3.3 V to 10V_ISO, 5V_ISO Power Supply
    3. 2.3 Highlighted Products
      1. 2.3.1 ISO7760
      2. 2.3.2 ISO7740
      3. 2.3.3 ISO7041
      4. 2.3.4 CSD19538Q2
      5. 2.3.5 CSD17382F4
      6. 2.3.6 TPL7407LA
      7. 2.3.7 TLV760
      8. 2.3.8 TLC555
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
      1. 3.1.1 Test Equipment Needed to Validate Board
      2. 3.1.2 Test Conditions
      3. 3.1.3 Test Procedure
    2. 3.2 Test Setup
    3. 3.3 Test Results
      1. 3.3.1 Functional Tests
      2. 3.3.2 Overcurrent Testing With External Fuse
      3. 3.3.3 Surge Testing
      4. 3.3.4 Multichannel SSR Driven From Two 24-VAC Transformers
      5. 3.3.5 Alternate SSR Topology for High Voltage
  9. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Documentation Support
    3. 4.3 支持资源
    4. 4.4 Trademarks
  10. 5About the Author

2.3.1 ISO7760

The ten channel SSR solution need a digital isolator circuit with a total of 10 channels. This is realized by using ISO7760 (6-channel digital isolator) and ISO7740 (4 channel digital isolator).

The ISO7760 devices are high-performance, six-channel digital isolators with 5000-VRMS (DW package) and 3000-VRMS (DBQ package) isolation ratings per UL 1577. This family of devices is also certified according to VDE, CSA, TUV, and CQC. The device has a robust isolation barrier with more than 100-Year projected lifetime, up to 12.8-kV surge capability and ±100 kV/μs Typical CMTI. The ISO776x family of devices provides high-electromagnetic immunity and low emissions at low-power consumption, while isolating CMOS or LVCMOS digital I/Os. Each isolation channel has a logic-input and logic-output buffer separated by a double capacitive silicon dioxide (SiO2) insulation barrier. The ISO776x family of devices is available in 16-pin SOIC and SSOP packages.

The ISO776x family of devices is available in all possible pin configurations such that all six channels are in the same direction, or one, two, or three channels are in reverse direction while the remaining channels are in forward direction. If the input power or signal is lost, the default output is high for devices without suffix F and low for devices with suffix F. These options allow the designer to select the variant providing safe off state when the input side power supply is lost. This reference design uses the device with suffix F to make sure that in the absence of input side powers supply all the SSR are turned off.