SLVS493E March   2004  – April 2022 TPS65130 , TPS65131

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 Switching Characteristics
    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 Power Conversion
      2. 7.3.2 Control
      3. 7.3.3 Enable
      4. 7.3.4 Load Disconnect
      5. 7.3.5 Soft-Start
      6. 7.3.6 Overvoltage Protection
      7. 7.3.7 Undervoltage Lockout
      8. 7.3.8 Overtemperature Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Power-Save Mode
      2. 7.4.2 Full Operation with VIN > 2.7 V
      3. 7.4.3 Limited Operation with VUVLO < VIN < 2.7 V
      4. 7.4.4 No Operation with VIN < VUVLO
  8. 8 Applications 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 Programming the Output Voltage
          1. 8.2.2.1.1 Boost Converter
          2. 8.2.2.1.2 Inverting Converter
        2. 8.2.2.2 Inductor Selection
        3. 8.2.2.3 Capacitor Selection
          1. 8.2.2.3.1 Input Capacitor
          2. 8.2.2.3.2 Output Capacitors
        4. 8.2.2.4 Rectifier Diode Selection
        5. 8.2.2.5 External PMOS Selection
        6. 8.2.2.6 Stabilizing the Control Loop
          1. 8.2.2.6.1 Feedforward Capacitor
          2. 8.2.2.6.2 Compensation Capacitors
      3. 8.2.3 Analog Supply Filter
        1. 8.2.3.1 RC-Filter
        2. 8.2.3.2 LC-Filter
      4. 8.2.4 Application Curves
  9. 9 Layout
    1. 9.1 Layout Guidelines
    2. 9.2 Layout Example
    3. 9.3 Thermal Considerations
  10. 10Device and Documentation Support
    1. 10.1 Device Support
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RGE|24
Thermal pad, mechanical data (Package|Pins)
Orderable Information
8.2.2.3.2 Output Capacitors

One of the major parameters necessary to define the capacitance value of the output capacitor is the maximum allowed output voltage ripple of the converter. This ripple is determined by two parameters of the capacitor, the capacitance and the ESR. It is possible to calculate the minimum capacitance needed for the defined ripple, supposing that the ESR is zero. Use Equation 7 for the boost converter output capacitor (C4min) and Equation 8 for the inverting converter output capacitor (C5min).

Equation 7. GUID-F028FA7D-F680-4794-BED6-2491FA9A9A68-low.gif
Equation 8. GUID-C0EF703E-AEDE-4D0A-911E-D65E877C98F7-low.gif

The parameter f is the switching frequency. ΔVPOS and ΔVNEG are the maximum allowed ripple voltages for each converter. Choosing a ripple voltage in the range of 10 mV requires a minimum capacitance of 12 μF. The total ripple is larger due to the ESR of the output capacitor. Use Equation 9 for he boost converter and Equation 10 for the inverting converter to calculate this additional ripple component.

Equation 9. GUID-54A72173-54EA-4639-9EEB-C4D01D9F6BB6-low.gif
Equation 10. GUID-CAB8280D-D467-4190-8C56-8D76C5FB1928-low.gif

In this example, an additional ripple of 2 mV is the result of using a typical ceramic capacitor with an ESR in the 10-mΩ range. The total ripple is the sum of the ripple caused by the capacitance and the ripple caused by the ESR of the capacitor. In this example, the total ripple is 10 mV.

Load transients can create additional ripple. When the load current increases rapidly, the output capacitor must provide the additional current until the inductor current increases by the control loop which sets a higher ON-time (duty cycle) of the main switch. The higher duty cycle results in longer inductor charging periods. The inductance itself also limits the rate of increase of the inductor current. When the load current decreases rapidly, the output capacitor must store the excess energy (stored in the inductor) until the regulator has decreased the inductor current by reducing the duty cycle. TI recommends using greater capacitance values, as the foregoing calculations show.