SLVSBK1E September   2012  – May 2014 TPS65631

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Simplified Schematic
  5. 5 Revision History
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 Handling Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Boost Converter
      2. 8.3.2 Inverting Buck-Boost Converter
        1. 8.3.2.1 Programming VNEG
        2. 8.3.2.2 Controlling the VNEG Transition Time
      3. 8.3.3 Soft-Start and Start-Up Sequence
      4. 8.3.4 Enable (CTRL)
      5. 8.3.5 Undervoltage Lockout
      6. 8.3.6 Short Circuit Protection
        1. 8.3.6.1 Short-Circuits During Normal Operation
        2. 8.3.6.2 Short-Circuits During Start-Up
      7. 8.3.7 Output Discharge During Shutdown
      8. 8.3.8 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Operation with VI < 2.9 V
      2. 8.4.2 Operation with VI ≈ VPOS (Diode Mode)
      3. 8.4.3 Operation with CTRL
  9. 9 Applications and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Inductor Selection
        2. 9.2.2.2 Capacitor Selection
        3. 9.2.2.3 Stability
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Trademarks
    3. 12.3 Electrostatic Discharge Caution
    4. 12.4 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9 Applications and Implementation

9.1 Application Information

Figure 10 shows a typical application circuit suitable for supplying AMOLED displays in smartphone applications. The circuit is designed to operate from a single-cell Li-Ion battery and generates a positive output voltage VPOS of 4.6 V and a negative output voltage of –4 V. Both outputs are capable of supplying up to 300 mA of output current.

9.2 Typical Application

Schem_03_SLVSBK1.gifFigure 10. Typical Application Schematic

9.2.1 Design Requirements

For this design example, use the following input parameters.

Table 2. Design Parameters

DESIGN PARAMETER EXAMPLE
Input voltage range 2.9 V to 4.5 V
Output voltage VPOS = 4.6V, VNEG = –4 V
Switching frequency 1.7 MHz

9.2.2 Detailed Design Procedure

In order to maximize performance, the TPS65631 has been optimized for use with a relatively narrow range of component values, and customers are strongly recommended to use the application circuit shown in Figure 10 with the components listed in Table 3 and Table 4.

9.2.2.1 Inductor Selection

The boost converter and inverting buck-boost converter have been optimized for use with 4.7 µH inductors, and it is recommended that this value be used in all applications. Customers using other values of inductor are strongly recommended to characterize circuit performance on a case-by-case basis.

Table 3. Inductor Selection

PARAMETER VALUE MANUFACTURER PART NUMBER
L1, L2 4.7 µH Coilmaster MMPP252012-4R7N
Toko 1239AS-H-4R7M
ABCO LPP252012-4R7N
Coilcraft XFL4020-4R7ML

9.2.2.2 Capacitor Selection

The recommended capacitor values are shown in Table 4. Applications using less than the recommended capacitance (e.g. to save PCB area) may experience increased voltage ripple. In general, the lower the output power, the lower the necessary capacitance.

Table 4. Capacitor Selection

PARAMETER VALUE MANUFACTURER PART NUMBER
C1 2 × 10 µF Murata GRM21BR71A106KE51
C2 10 µF Murata GRM21BR71A106KE51
C3 2 × 10 µF Murata GRM21BR71A106KE51
C4 100 nF Murata GRM21BR71E104KA01

9.2.2.3 Stability

Applications using component values that differ significantly from those recommended in Table 3 and Table 4 should be checked for stability over the full range of operating conditions.

9.2.3 Application Curves

The performance shown in the following graphs was obtained using the circuit shown in Figure 10 and the external components shown in Table 3 and Table 4. The output voltage settings for these measurements were VPOS = 4.6 V and VNEG = –4 V.

SLVSBK1_APP_PERF_01.png
Figure 11. Efficiency vs. Output Current
AppPerf_03_SLVSBK1.gifFigure 13. VPOS Switch Voltage, Inductor Current and Output Voltage Ripple (IO = 100 mA)
AppPerf_05_SLVSBK1.gifFigure 15. VNEG Switch Voltage, Inductor Current and Output Voltage Ripple (IO = 100 mA)
SLVSBK1_APP_PERF_07.png
Figure 17. Boost Converter Line Regulation
SLVSBK1_APP_PERF_09.png
Figure 19. Boost Converter Load Regulation
AppPerf_11_SLVSBK1.gifFigure 21. Line Transient Response
AppPerf_13_SLVSBK1.gifFigure 23. Inverting Buck-Boost Converter Load Transient Response
AppPerf_02_SLVSBK1.gifFigure 12. Start-Up Waveforms
AppPerf_04_SLVSBK1.gifFigure 14. VPOS Switch Voltage, Inductor Current and Output Voltage Ripple (IO = 300 mA)
AppPerf_06_SLVSBK1.gifFigure 16. VNEG Switch Voltage, Inductor Current and Output Voltage Ripple (IO = 300 mA)
SLVSBK1_APP_PERF_08.png
Figure 18. Inverting Buck-Boost Converter Line Regulation
SLVSBK1_APP_PERF_10.png
Figure 20. Inverting Buck-Boost Converter Load Regulation
AppPerf_12_SLVSBK1.gifFigure 22. Boost Converter Load Transient Response