EE Senior Design Team ß: Design Report for Push-Button Power

Abstract

In contrast to conventional college laboratory power supplies, Push-Button Power will be stable and user-friendly. The device will feature fixed 5V and +/-15V supplies and a variable +/-35V supply. A 16-bit Motorola 68HC12 microcontroller will manage a combination of switching and digitally controlled shunt supplies. The user interface will consist of a custom keypad for input and a multi-line LCD panel for output. In addition to technical specifications, a budget and plan for implementing the project are presented.

Contents

• Executive Summary
• Introduction
• Problem Statement
• High Level Specifications
  • Capabilities
  • User Interface
  • Use Cases
    • Set Voltage
    • Stop System
    • Short Circuit
• Design Procedures
  • System Block Diagram
  • Supply Blocks
    • Design Parameters
    • Overview of solutions
    • AC to DC conversion
      • Switching Regulators vs. Transformers
      • Transformer And Rectifier Board
    • Measurement, Feedback and Control
      • Board Selection
      • Measurement system
      • Feedback
    • Fixed Supplies
    • Microprocessor and Control Supplies
    • Variable Supplies
  • Control Blocks
    • Processor Hardware
    • Processor Software
    • LCD
    • Keypad and Controller
    • COP
      • COP to Processor Interface
      • Relay Interface
    • Alarm
    • Thermal Monitor
• Simulation and Laboratory Testing
• Spring Implementation Schedule
• Budget
  • Time Already Spent
  • Estimated Time To Spend
  • Cost of Parts
• Conclusion
• Appendices
  • Appendix A: Bibliography
  • Appendix B: Tracking Progress on the Web
  • Appendix C: Microprocessor Specifications
  • Appendix D: LCD Panel Specifications
  • Appendix E: Keypad And Keypad Controller Specifications
  • Appendix F: Alarm Circuit Specifications
  • Appendix G: COP Circuit Specifications
  • Appendix H: National Application Note 556
  • Appendix I: National ADC10462 Data Sheet
  • Appendix J: Maxim MAX471 Data Sheet
  • Appendix K: Supply Schematics
  • Appendix L: Regulator Specifications

Figures

• Figure 1: Keypad Layout
• Figure 2: Display Format
• Figure 3: System Block Diagram
• Figure 4: Block Diagram For Supply Section
• Figure 5: Schematic of Flyback Switching Supply
• Figure 6: Main Software Loop
• Figure 7: Supply Control Subroutine
• Figure 8: Keypad ISR
• Figure 9: Comparison Of Set Voltage And Output Voltages
• Figure 10: Digital Simulation
• Figure 11: Comparison of R2 v. LM338 Output
• Figure 12: Spring Implementation Plan

Tables

• Table 1: I/O Pin Requirements
• Table 2: Accumulated Project Time
• Table 3: Estimated Project Time
• Table 4: Bill of Materials