SLVS977B February   2010  – July 2016 TPS61325

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD 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 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1  LED High-current Regulators, Unused Inputs
      2. 9.3.2  Safety Timer Accuracy
      3. 9.3.3  Current Limit Operation
      4. 9.3.4  Start-Up Sequence
      5. 9.3.5  Power Good (Flash Ready)
      6. 9.3.6  LED Temperature Monitoring
      7. 9.3.7  Hot Die Detector
      8. 9.3.8  Undervoltage Lockout
      9. 9.3.9  Storage Capacitor Active Cell Balancing
      10. 9.3.10 RED Light Privacy Indicator
      11. 9.3.11 White LED Privacy Indicator
      12. 9.3.12 Storage Capacitor, Precharge Voltage Calibration
      13. 9.3.13 Storage Capacitor, Adaptive Precharge Voltage
      14. 9.3.14 Serial Interface Description
        1. 9.3.14.1 F/S-Mode Protocol
        2. 9.3.14.2 HS-Mode Protocol
    4. 9.4 Device Functional Modes
      1. 9.4.1  Down Mode In Voltage Regulation Mode
      2. 9.4.2  Power-Save Mode Operation, Efficiency
      3. 9.4.3  Mode Of Operation: DC-Light and Flashlight
      4. 9.4.4  Flash Strobe Is Level Sensitive (STT = 0): LED Strobe Follows STRB0 and STRB1 Inputs
      5. 9.4.5  Flash Strobe Is Leading Edge Sensitive (STT = 1): One-Shot LED Strobe
      6. 9.4.6  LED Failure Modes and Overvoltage Protection
      7. 9.4.7  Hardware Voltage Mode Selection
      8. 9.4.8  Flashlight Blanking (Tx-MASK)
      9. 9.4.9  Shutdown
      10. 9.4.10 Thermal Shutdown
    5. 9.5 Programming
      1. 9.5.1 TPS6132x I2C Update Sequence
    6. 9.6 Register Maps
      1. 9.6.1  Slave Address Byte
      2. 9.6.2  Register Address Byte
      3. 9.6.3  REGISTER0 (address = 0x00)
      4. 9.6.4  REGISTER1 (address = 0x01)
      5. 9.6.5  REGISTER2 (address = 0x02)
      6. 9.6.6  REGISTER3 (address = 0x03)
      7. 9.6.7  REGISTER4 (address = 0x04)
      8. 9.6.8  REGISTER5 (address = 0x05)
      9. 9.6.9  REGISTER6 (address = 0x06)
      10. 9.6.10 REGISTER7 (address = 0x07)
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 4100-mA Two White High-Power LED Flashlight With Storage Capacitor
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
          1. 10.2.1.2.1 Inductor Selection
          2. 10.2.1.2.2 Input Capacitor
          3. 10.2.1.2.3 Output Capacitor
          4. 10.2.1.2.4 NTC Selection
          5. 10.2.1.2.5 Checking Loop Stability
        3. 10.2.1.3 Application Curves
      2. 10.2.2 Other Application Circuit Examples
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
    3. 12.3 Thermal Considerations
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Third-Party Products Disclaimer
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Community Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

12 Layout

12.1 Layout Guidelines

As for all switching power supplies, the layout is an important step in the design, especially at high peak currents and high switching frequencies. If the layout is not carefully done, the regulator could show stability problems as well as EMI problems. Therefore, use wide and short traces for the main current path and for the power ground tracks.

The input capacitor, output capacitor, and the inductor must be placed as close as possible to the IC. Use a common ground node for power ground and a different one for control ground to minimize the effects of ground noise. Connect these ground nodes at any place close to one of the ground pins of the IC.

TI recommends using short traces to lay out the control ground, separated from the power ground traces. This avoids ground shift problems, which can occur due to superimposition of power-ground current and control-ground current.

12.2 Layout Example

TPS61325 TPS61326 top_layout_lvs977.gif Figure 89. Suggested Layout (Top)

12.3 Thermal Considerations

Implementation of integrated circuits in low-profile and fine-pitch surface-mount packages typically requires special attention to power dissipation. Many system-dependant issues such as thermal coupling, airflow, added heat sinks and convection surfaces, and the presence of other heat-generating components affect the power-dissipation limits of a given component.

Three basic approaches for enhancing thermal performance are listed below:

  • Improving the power dissipation capability of the PCB design
  • Improving the thermal coupling of the component to the PCB
  • Introducing airflow in the system

Junction-to-ambient thermal resistance is highly application and board-layout dependent. In applications where high maximum power dissipation exists, pay special attention to thermal dissipation issues in board design. The maximum junction temperature (TJ) of the TPS6132x is 150°C.

The maximum power dissipation is especially critical when the device operates in the linear down mode at high LED current. For single pulse power thermal analysis, for example, flashlight strobe, the allowable power dissipation for the device is given by Figure 90. These values are derived using the reference design.

TPS61325 TPS61326 sing_pulse_lvs957.gif Figure 90. Single Pulse Power Capability