SLVS992D September   2009  – April 2019 TPS61093

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  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 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 Shutdown and Load Discharge
      2. 7.3.2 Overload and Overvoltage Protection
      3. 7.3.3 UVLO
      4. 7.3.4 Thermal Shutdown
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 15 V Output Boost Converter
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Custom Design With WEBENCH® Tools
          2. 8.2.1.2.2 Output Program
          3. 8.2.1.2.3 Without Isolation FET
          4. 8.2.1.2.4 Start-Up
          5. 8.2.1.2.5 Switch Duty Cycle
          6. 8.2.1.2.6 Inductor Selection
          7. 8.2.1.2.7 Input and Output Capacitor Selection
          8. 8.2.1.2.8 Small Signal Stability
        3. 8.2.1.3 Application Curves
      2. 8.2.2 10 V, –10 V Dual Output Boost Converter
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
      2. 11.1.2 Development Support
        1. 11.1.2.1 Custom Design With WEBENCH® Tools
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.1.2.8 Small Signal Stability

The TPS61093 integrates slope compensation and the RC compensation network for the internal error amplifier. Most applications are control loop stable if the recommended inductor and input/output capacitors are used. For those few applications that require components outside the recommended values, the internal error amplifier’s gain and phase are presented in Figure 9.

TPS61093 bode_plot_lvs992.gifFigure 9. Bode Plot of Error Amplifier Gain and Phase

The RC compensation network generates a pole fp-ea of 57 kHz and a zero fz-ea of 1.9 kHz, shown in Figure 9. Use Equation 7 to calculate the output pole, fP, of the boost converter. If fP << fz-ea. due to a large capacitor beyond 10 μF, for example, a feed forward capacitor on the resistor divider, as shown in Figure 9, is necessary to generate an additional zero fz-f. to improve the loop phase margin and improve the load transient response. The low frequency pole fp-f and zero fz-f generated by the feed forward capacitor are given by Equation 8 and Equation 9:

Equation 7. TPS61093 eq8_fp_lvs992.gif
Equation 8. TPS61093 eq9_fpf_lvs992.gif
Equation 9. TPS61093 eq10_fzf_lvs992.gif

where

  • Cff = the feed-forward capacitor

For example, in the typical application circuitry (see Figure 7), the output pole fP is approximately 1 kHz. When the output capacitor is increased to 100 μF, then the fP is reduced to 10 Hz. Therefore, a feed-forward capacitor of 10 nF compensates for the low frequency pole.

A feed-forward capacitor that sets fz-f near 10 kHz improves the load transient response in most applications, as shown in Figure 11.