SLVS704C November   2011  – January 2017 TPS65135

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Advanced Power-Save Mode for Light-Load Efficiency
      2. 7.3.2 Buck-Boost Mode Operation
      3. 7.3.3 Inherently Good Line-Transient Regulation
      4. 7.3.4 Overvoltage Protection
      5. 7.3.5 Short-Circuit Protection
      6. 7.3.6 Soft-Start Operation
      7. 7.3.7 Output-Current Mismatch
      8. 7.3.8 Setting the Output Voltages
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operation with 2.5 V ≤ VI ≤ 5.5 V
      2. 7.4.2 Operation with VI < 2.5 V
      3. 7.4.3 Operation with VI > 5.5 V
      4. 7.4.4 Operation with EN
  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 Choosing a Suitable Inductor
        2. 8.2.2.2 Choosing Suitable Input and Output Capacitors
        3. 8.2.2.3 Choosing Suitable Feedback Resistors
        4. 8.2.2.4 Measurement Circuit
      3. 8.2.3 Application Curves
  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. 11.2 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 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

8.1 Application Information

The TPS65135 device can be used to generate spilt-rail supplies from input supply voltages in the range 2.5 V to 5.5 V and has been optimized for use with 3.3-V rails of single-cell Li-ion batteries. It can generate positive output voltages up to 6 V and negative voltages down to –7 V with buck-boost action (i.e. the input supply voltage may be above or below the positive output voltage), as long as the output current mis-match is 50% or less. Both outputs are controlled by the EN pin: a high logic level enables both outputs, and a low logic level disables them. An integrated UVLO function disables the device when the input supply voltage is too low for proper operation.

8.2 Typical Application

Figure 8 shows a typical application for a ±5-V AMOLED display supply.

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TPS65135 Schem_01_SLVS704.gif Figure 8. Standard Application ±5-V Supply

8.2.1 Design Requirements

Table 2 shows the design requirements for a ±5-V AMOLED supply application used as an example to illustrate the design process.

Table 2. Design Parameters

PARAMETER SYMBOL EXAMPLE VALUE
Input Supply Voltage Range VI 2.5 V to 5.5 V
Positive Output Voltage VO(POS) 5 V
Negative Output Voltage VO(NEG) –5 V
Maximum Positive Output Current IO(POS) max 80 mA
Maximum Negative Output Current IO(NEG) max –80 mA

8.2.2 Detailed Design Procedure

8.2.2.1 Choosing a Suitable Inductor

The TPS65135 device is internally compensated and operates best with a 2.2-µH inductor. For this type of converter, selection of the inductor is a key element in the design process because it has a big impact on the efficiency, the line and load transient response, and the maximum output current the device is able to deliver. Because the inductor ripple current is fairly large in the SIMO topology, the inductor core losses largely determine converter efficiency. As a result, an inductor with a relatively large dc winding resistance (DCR) but low core losses can often achieve higher converter efficiencies than other inductors with lower DCR but higher core losses.

As previously described, the converter's line transient response is highest when the converter operates in DCM, and since larger inductor values cause the converter to enter CCM operation at lower load currents, smaller inductor values give the best line transient response. The formula to calculate the output current at which the converter enters CCM operation is shown in Equation 3. The inductors listed in Table 3 achieve a good overall converter efficiency while having a low height. The first two TOKO inductors achieve the highest efficiency (almost identical) followed by the LPS3008. The best compromise between efficiency and inductor size is given by the XFL2006 inductor. The inductor saturation current should typically be 1 A or higher, however, if the output current required by the application is low, inductors with smaller saturation current ratings may be considered.

Table 3. Inductor Selection

INDUCTOR VALUE COMPONENT SUPPLIER DIMENSIONS in mm Isat / DCR
2.2 µH TOKO DFE252010C 2.5 x 2 x 1 1.9 A / 130 mΩ
TOKO DFE252012C 2.5 x 2 x 1.2 2.2 A / 90 mΩ
Coilcraft XFL2006-222 2 × 1.9 × 0.6 0.8 A / 278 mΩ
Coilcraft LPS3008-222 3 × 3 × 0.8 1.1 A / 175 mΩ
Samsung CIG2MW2R2NNE 2 × 1.6 × 1 1.2 A / 110 mΩ
TOKO FDSE0312-2R2 3.3 × 3.3 × 1.2 1.2 A / 160 mΩ
ABCO LPF3010T-2R2 2.8 × 2.8 × 1 1.0 A / 100 mΩ
Maruwa CXFU0208-2R2 2.65 × 2.65 × 0.8 0.85 A / 185 mΩ

8.2.2.2 Choosing Suitable Input and Output Capacitors

The TPS65135 device typically requires a 10-µF ceramic input capacitor. Larger values can be used to lower the input voltage ripple. Table 4 lists capacitors suitable for use on the TPS65135 input.

Table 4. Input Capacitor Selection

CAPACITOR COMPONENT SUPPLIER SIZE
10 µF / 6.3V Murata GRM188R60J106ME84D 0603
10 µF / 6.3 V Taiyo Yuden JMK107BJ106 0603

A 4.7-µF output capacitor is generally sufficient for most applications, but larger values can be used as well for improved load- and line-transient response at higher load currents. The capacitors of Table 5 have been found to work well with the TPS65135 device.

Table 5. Output Capacitor Selection

CAPACITOR COMPONENT SUPPLIER SIZE
10 µF / 6.3 V Murata GRM188R60J106ME84D 0603
4.7 µF / 10 V Taiyo Yuden LMK107BJ475 0603
10 µF / 6.3 V Taiyo Yuden JMK107BJ106 0603

8.2.2.3 Choosing Suitable Feedback Resistors

Equation 7 can be used to calculate a suitable value for R2, so that the recommended current of ≈10 µA flows through the feedback resistors.

The value of R1 can be calculated by rearranging Equation 7, so that

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Equation 10. TPS65135 Eqn_09_SLVS704.gif

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Inserting R2 = 120 kΩ, Vref1 = 1.24 V and VO(POS) = 5 V into Equation 10, we get

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Equation 11. TPS65135 Eqn_12_SLVS704.gif

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The closest 1%-tolerance standard value is 365 kΩ, which will generate a nominal output voltage of 5.012 V.

The value of R3 can be calculated by rearranging Equation 9, so that

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Equation 12. TPS65135 Eqn_11_SLVS704.gif

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Inserting R2 = 120 kΩ, Vref1 = 1.24 V and VO(NEG) = –5 V into Equation 12, we get

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Equation 13. TPS65135 Eqn_13_SLVS704.gif

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The closest 1%-tolerance standard value is 487 kΩ, which will generate a nominal output voltage of –5.032 V.

8.2.2.4 Measurement Circuit

The following application curves were obtained using the circuit shown in Figure 9 and the external components listed in Table 6.

TPS65135 Schem_02_SLVS704.gif Figure 9. Measurement Circuit

Table 6. Component List

Reference Description Manufacturer and Part Number
C1, C2, C3 10 μF, 6.3 V, 0603, X5R, ceramic Murata, GRM188R60J106ME84D
C4 100 nF, 10 V, 0603, X7R, ceramic Murata, GRM188R71H104KA93D
L1 2.2 μH, 2.2 A, 90 mΩ, 2.5 mm × 2.0 mm × 1.2 mm Toko, 1239AS-H-2R2M
R1 Depending on the output voltage, 1%, (all measurements with ±5 V output voltage uses 365 kΩ)
R2 Depending on the output voltage, 1%, (all measurements with ±5 V output voltage uses 120 kΩ)
R3 Depending on the output voltage, 1%, (all measurements with ±5 V output voltage uses 487 kΩ)
U1 TPS65135RTE Texas Instruments

8.2.3 Application Curves

In the following curves VI = 3.7 V, VO(POS) = 5 V, VO(NEG) = –5 V unless otherwise noted. Where the symbol IO is used, it implies that IO(POS) = |IO(NEG)|. All measurements at TA = 25°C unless otherwise noted.

TPS65135 TypChar_01_SLVS704.png
L1 = 2.2 µH
Figure 10. Efficiency vs Load Current
TPS65135 TypChar_04_SLVS704.gif
IO = 10 mA
Figure 12. Operation at Light Load Current (DCM)
TPS65135 TypChar_06_SLVS704.gif
IO = 10 mA VI = 2.9 V, 3.4 V
Figure 14. Line Transient Response
TPS65135 TypChar_08_SLVS704.gif
IO = 0 mA
Figure 16. Start Up (VI Rising)
TPS65135 TypChar_10_SLVS704.gif
IO = 0 mA
Figure 18. Shut Down – (VI Falling)
TPS65135 TypChar_12_SLVS704.gif
IO = 10 mA, 50 mA
Figure 20. Load Transient Response
TPS65135 TypChar_16_SLVS704.png
Figure 22. Positive Output Load Regulation
TPS65135 TypChar_14_SLVS704.png
Figure 24. Switching Frequency vs Load Current
TPS65135 TypChar_03_SLVS704.gif
Figure 26. Output Current Mismatch
TPS65135 TypChar_02_SLVS704.png
L1 = 4.7 µH
Figure 11. Efficiency vs Load Current
TPS65135 TypChar_05_SLVS704.gif
IO = 80 mA
Figure 13. Operation at High Load Current (CCM)
TPS65135 TypChar_07_SLVS704.gif
IO = 50 mA VI = 2.9 V, 3.4 V
Figure 15. Line Transient Response
TPS65135 TypChar_09_SLVS704.gif
IO = 0 mA
Figure 17. Start Up (V(EN) Rising)
TPS65135 TypChar_11_SLVS704.gif
IO = 0 mA
Figure 19. Shut Down (V(EN) Falling)
TPS65135 TypChar_13_SLVS704.gif
IO = 20 mA, 80 mA
Figure 21. Load Transient Response
TPS65135 TypChar_17_SLVS704.png
Figure 23. Negative Output Load Regulation
TPS65135 TypChar_15_SLVS704.png
Figure 25. Input Current vs Input Voltage