SLVS074J January   1983  – September 2026 TL494

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  Electrical Characteristics, Reference Section
    6. 5.6  Electrical Characteristics, Oscillator Section
    7. 5.7  Electrical Characteristics, Error-Amplifier Section
    8. 5.8  Electrical Characteristics, Output Section
    9. 5.9  Electrical Characteristics, Dead-Time Control Section
    10. 5.10 Electrical Characteristics, PWM Comparator Section
    11. 5.11 Electrical Characteristics, Total Device
    12. 5.12 Switching Characteristics
    13. 5.13 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 5V Reference Regulator
      2. 7.3.2 Oscillator
      3. 7.3.3 Dead-time Control
      4. 7.3.4 Comparator
      5. 7.3.5 Pulse-Width Modulation (PWM)
      6. 7.3.6 Error Amplifiers
      7. 7.3.7 Output-Control Input
      8. 7.3.8 Output Transistors
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Input Power Source
        2. 8.2.2.2 Control Circuits
          1. 8.2.2.2.1 Oscillator
          2. 8.2.2.2.2 Error Amplifier
          3. 8.2.2.2.3 Current-Limiting Amplifier
          4. 8.2.2.2.4 Soft Start and Dead Time
        3. 8.2.2.3 Inductor Calculations
        4. 8.2.2.4 Output Capacitance Calculations
        5. 8.2.2.5 Transistor Power-Switch Calculations
      3. 8.2.3 Application Curves for Output Characteristics
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
        1. 8.4.1.1 Feedback Traces
        2. 8.4.1.2 Input/Output Capacitors
        3. 8.4.1.3 Compensation Components
        4. 8.4.1.4 Traces and Ground Planes
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Documentation Support
      1. 9.3.1 Related Documentation
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

8.2.2.3 Inductor Calculations

Figure 8-6 shows the switching circuit.

TL494 Switching Circuit Figure 8-6 Switching Circuit

The size of the inductor (L) required is:

Equation 14. d = d u t y   c y c l e = V O V I = 5 V 32 V = 0.156
Equation 15. f = 20 k H z   ( d e s i g n   o b j e c t i v e )
Equation 16. t O N = t i m e   o n   ( S 1   c l o s e d ) = ( 1 f ) × d = 7.8 μ s
Equation 17. t O F F = t i m e   o f f   ( S 1   o p e n ) = ( 1 f ) - t o n = 42.2 μ s
Equation 18. L ≉ ( V I - V O ) × t O N ∆ I L ≉ [ ( 32 V - 5 V ) × 7.8 μ s ] 1.5 A ≉ 140.4 μ H