SLUS719H MARCH   2007  – May 2019 TPS40192 , TPS40193

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Application Diagram
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Dissipation Ratings
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Voltage Reference
      2. 7.3.2  Oscillator
      3. 7.3.3  UVLO
      4. 7.3.4  Enable Functionality
      5. 7.3.5  Start-Up Sequence and Timing
      6. 7.3.6  Selecting the Short Circuit Current
      7. 7.3.7  5-V Regulator
      8. 7.3.8  Prebias Start-Up
      9. 7.3.9  Drivers
      10. 7.3.10 Power Good
      11. 7.3.11 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Continuous Conduction Mode
      2. 7.4.2 Low-Quiescent Shutdown
  8. 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  Selecting the Switching Frequency
        2. 8.2.2.2  Inductor Selection
        3. 8.2.2.3  Output Capacitor Selection (C8)
        4. 8.2.2.4  Peak Current Rating of the Inductor
        5. 8.2.2.5  Input Capacitor Selection (C7)
        6. 8.2.2.6  MOSFET Switch Selection (Q1, Q2)
        7. 8.2.2.7  Boot Strap Capacitor
        8. 8.2.2.8  Input Bypass Capacitor (C6)
        9. 8.2.2.9  BP5 Bypass Capacitor (C5)
        10. 8.2.2.10 Input Voltage Filter Resistor (R11)
        11. 8.2.2.11 Short Circuit Protection (R9)
        12. 8.2.2.12 Feedback Compensation (Modeling the Power Stage)
        13. 8.2.2.13 Feedback Divider (R7, R8)
        14. 8.2.2.14 Error Amplifier Compensation (R6, R10, C1, C2, C3)
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Related Devices
      2. 11.1.2 Device Nomenclature
    2. 11.2 Documentation Support
    3. 11.3 Related Links
    4. 11.4 Receiving Notification of Documentation Updates
    5. 11.5 Community Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.2.2.14 Error Amplifier Compensation (R6, R10, C1, C2, C3)

Place two zeros at 50% and 100% of the resonance frequency to boost the phase margin before resonance frequency generates –180° of phase shift. For fRES = 11.7 kHz, fZ1 = 5.8 kHz and fZ2 = 11 kHz. Selecting the crossover frequency (fCO) of the control loop between 3 times the LC filter resonance and 1/5th the switching frequency. For most applications 1/10th the switching frequency provides a good balance between ease of design and fast transient response.

  • If fESR < fCO ; fP1 = fESR and fP2 = 4 × fCO
  • If fESR > 2 × fCO; fP1 = fCO and fP2 = 8 × fCO.

    • For this design

  • fSW = 600 kHz
  • fRES = 11.7 kHz
  • fESR = 636 kHz
  • fCO = 60 kHz and because
  • fESR > 2 × fCO, FP1 = fCO = 60 kHz and fP2 = 4 × fCO = 500 kHz.

Because fCO < fESR the power stage gain at the desired crossover can be approximated in Equation 31.

Equation 31. TPS40192 TPS40193 q_apsfco_slus719.gif

Table 5. Error Amplifier Design Parameters

PARAMETER SYMBOL VALUE UNITS
First zero frequency fZ1 5.8 kHz
Second zero frequency fZ2 11.0
First pole frequency fP1 60
Second pole frequency fP2 500
Midband gain AMID(band) 1.86 V/V

Approximate C2 with the formula described in Equation 32.

Equation 32. TPS40192 TPS40193 q_c2_slus719.gif

For a calculated value for C2 of 723 pF, the closest standard capacitor value is 1000 pF.

Approximate R10 using Equation 33.

Equation 33. TPS40192 TPS40193 q_r10_slus719.gif

For a calculated value for R10 of 2.65 kΩ, the closest standard resistor value is 2.61 kΩ.

Calculate R6 using Equation 34.

Equation 34. TPS40192 TPS40193 q_r6_slus719.gif

For a calculated value for R6 of 4.29 kΩ, the closest standard resistor value is 4.22 kΩ.

Calculate C1 and C3 using Equation 35 and Equation 36.

Equation 35. TPS40192 TPS40193 q_c3_slus719.gif
Equation 36. TPS40192 TPS40193 q_c1_slus719.gif

Using the a standard value close to 75 pF, select C1 = 100 pF. Likewise, using a standard value close to 6.5 nF, select C3 = 10 nF.

The error amplifier straight line approximation transfer function is described in Figure 18.

TPS40192 TPS40193 fre_xfer_log_slus719.gifFigure 18. Error Amplifier Transfer Function Approximation