JAJU873 August   2020

 

  1.   概要
  2.   リソース
  3.   特長
  4.   アプリケーション
  5.   5
  6. 1 System Description
    1. 1.1 Medical Respiratory Systems
    2. 1.2 Respirator System Components
    3. 1.3 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Brushless DC Motor (BLDC)
        1. 2.2.1.1 DRV8323RS BLDC Motor Driver Design Calculations
        2. 2.2.1.2 BLDC Motor Driver Circuit
      2. 2.2.2 Solenoid Valve Drivers
        1. 2.2.2.1 DRV8847 Solenoid Driver Design Calculations
        2. 2.2.2.2 Solenoid Driver Circuit
      3. 2.2.3 Power Tree Architecture
        1. 2.2.3.1 Input protection - overvoltage and reverse voltage
        2. 2.2.3.2 LM5122 Boost Design Calculations
        3. 2.2.3.3 LMR33630 Buck Design Calculations
        4. 2.2.3.4 Secondary Power Stage – TPS62840 3.3V Buck
        5. 2.2.3.5 Secondary Power Stage – TPS7A02 3.3V LDO
        6. 2.2.3.6 Power Tree Circuit
    3. 2.3 Highlighted Products
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware and Software Requirements
    2. 3.2 Test Setup
      1. 3.2.1 Hardware Configuration
      2. 3.2.2 Software Configuration
    3. 3.3 Test Results
      1. 3.3.1 Motor Test Result
      2. 3.3.2 Valve Test Result
      3. 3.3.3 Power Tree Test Result
      4. 3.3.4 Key Test Summary
  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 サポート・リソース
    4. 4.4 Trademarks
  10. 5About the Author

2.1 Block Diagram

GUID-20200801-CA0I-1VVD-PJPJ-ZD4NGZRPRSHV-low.gifFigure 2-1 TIDA-010072 Block Diagram

This reference design is capable of driving a BLDC motor, four unidirectional valves, and two bidirectional valves in a compact and efficient platform. The DRV8323RS is selected as the BLDC motor driver with FOC control provided from an off-board Piccolo MCU. Three TMP1075 Integrted Circuits (ICs) are selected to monitor the temperature of the BLDC half-bridges to prevent over-temperature conditions. Two DRV8847 ICs are selected to drive the solenoid valves with control provided by the MSP430FR2155.

The system is capable of running off of a wide input voltage range of 6-28 V. This range covers typical battery input voltages as well as typical regulated DC voltages that are seen in many respiratory systems. The LM5122 boost controller is used to convert lower input voltages to 14 V, with a pass-through mode for higher voltages. The LMR33630 buck converter is used to step the output of the LM5122 down to a regulated 12 V, which is used by the DRV8847 ICs. The DRV8323RS uses the full input voltage range, and also integrates a buck converter, which is used to step the full input voltage range down to 4 V. The TPS7A02 low-dropout linear regulator (LDO) is selected to step 4 V down to a clean 3.3 V to power the temperature sensors. The TPS62840 buck converter is selected to step 4 V down to 3.3 V to provide power for the remaining digital devices including the MCU, and system pull-up resistors.