TIDUF39 March   2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 DAC70502: Dual-Channel, 1-LSB INL, 14-Bit, SPI Voltage-Output Digital-to-Analog Converter (DAC)
      2. 2.3.2 INA818: 35μV Offset, 8nV/√Hz Noise, Low-Power, Precision Instrumentation Amplifier
      3. 2.3.3 OPA192: High-Voltage, Rail-to-Rail Input/Output, 5µV, 0.2µV/°C, Precision Operational Amplifier
      4. 2.3.4 LM5146: 100V Synchronous Buck DC/DC Controller With Wide Duty Cycle Range
  9. 3System Design Theory
    1. 3.1 Constant Current Control Design
    2. 3.2 Constant Current and Voltage Simulation
  10. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
    2. 4.2 Software Requirements
    3. 4.3 Test Setup
      1. 4.3.1 Constant Current Test Setup
      2. 4.3.2 Constant Voltage Test Setup
    4. 4.4 Test Results
      1. 4.4.1 Current Control Accuracy
      2. 4.4.2 Voltage Control Accuracy
      3. 4.4.3 CC, CV Transformation
      4. 4.4.4 Constant Current Transient Response
      5. 4.4.5 Constant Voltage Transient Response
      6. 4.4.6 Voltage Ripple at Short Circuit
      7. 4.4.7 Tracking DC-DC output
  11. 5Design and Documentation Support
    1. 5.1 Design Files
      1. 5.1.1 Schematics
      2. 5.1.2 BOM
    2. 5.2 Tools and Software
    3. 5.3 Documentation Support
    4. 5.4 Support Resources
    5. 5.5 Trademarks
  12. 6About the Author

4.1 Hardware Requirements

Figure 4-1 shows the hardware snapshot for this reference design. Jumper J9, J10, J12, and J13 configure the power rail connections to circuitry on the board. The J5 jumper provides reference voltage programmed by the DAC to the control system for configuring operation mode. J7 can disable the solid-state relay to interrupt output states. J8 controls functionality of the output switch relay based on the sensing signal from the feedback, safeguarding the circuit from reverse polarity.

TIDA-010089 TIDA010089 Hardware Figure 4-1 TIDA010089 Hardware

The MOSFETs in the output stage are responsible for either sourcing or sinking current from the battery side, the excess heat must be carried away from both MOSFETS to provide normal operation. The heat sink and fan is applied in this design to dissipate any excess amount of heat. Particularly, the P-channel metal-oxide-semiconductor (PMOS) handles sinking the current and has higher thermal resistance. The selection of the heat sink and fan is contingent upon the specific power dissipation requirements and case temperature criteria. In this design, the target power dissipation is 8W without the fan, and the chosen heat sink is capable of dissipating 20W with an airflow of 30ft3/min. This makes sure that the thermal management of the system meets the design specifications for reliable operation.