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

1.3 Key System Specifications

This reference design showcases a compact driver system design used to drive a single brushless DC (BLDC) motor and up to six solenoid valves. The BLDC motor is used to quietly and efficiently generate pressurized airflow. The solenoid valves are used to both create different gas mixtures and to provide safety mechanisms in the event of failures. The design supports up to 10 A of continuous motor drive, which can cover the motor operating requirements in most respirator applications. Additionally, this design includes a power tree capable of handling typical regulated DC voltage rails and battery voltage levels (6-28 V) for applications that are moving to portable designs.

Table 1-4 lists the different characteristics and specifications of the TIDA-010072 board.

Table 1-4 TIDA-010072 Key System Specifications
KEY REQUIREMENTSTYPICAL
Input Voltage6-28 V
BLDC Motor Current10 A Continuous, 20 A peak
Max electrical frequency1.2 kHz
Max Pulse Width Modulation (PWM) Frequency45 kHz
Key Protection FeaturesSurge, OCP, UVLO, OTW/OTSD, and RVP
BLDC Motor Max Acceleration200 kRPM/s
Solenoid Operating Voltage12 V
Unidirectional Solenoid Drive4 Channels
Bidirectional Solenoid Drive2 Channels
Solenoid Drive Current4x 0.5 A (unidirectional), 2x 0.5 A (bidirectional)
Max valve response time1 ms
Operation Temperature Range5 to 40 °C

DRV8323RS Integrated Protection Features:

  • VM Undervoltage Lockout (UVLO)
  • Charge Pump Undervoltage (CPUV)
  • MOSFET Overcurrent Protection (OCP)
  • Gate Driver Fault (GDF)
  • Thermal Warning and Shutdown (OTW/OTSD)
  • Fault Condition Indicator (nFAULT)

DRV8847 Integrated Protection Features:

  • VM undervoltage lockout
  • Overcurrent protection
  • Open load detection
  • Thermal shutdown
  • Fault condition indication pin (nFAULT)