ZHCSHC3B january   2018  – june 2023 TPS61280D , TPS61280E , TPS61281D

PRODUCTION DATA  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  5. 4 Revision History
  6. 5 说明（续）
  7. 6 Device Comparison Table
  8. 7 Pin Configuration and Functions
  9. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 I2C Interface Timing Characteristics #GUID-BD85FD7C-B9AF-4F5D-9DFF-CD61365A592A/SLVS5401494
    7. 8.7 I2C Timing Diagrams
    8. 8.8 Typical Characteristics
  10. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Voltage Scaling Management (VSEL)
      2. 9.3.2 Spread Spectrum, PWM Frequency Dithering
    4. 9.4 Device Functional Modes
      1. 9.4.1 Power-Save Mode
      2. 9.4.2 Pass-Through Mode
      3. 9.4.3 Mode Selection
      4. 9.4.4 Current Limit Operation
      5. 9.4.5 Start-Up and Shutdown Mode
      6. 9.4.6 Undervoltage Lockout
      7. 9.4.7 Thermal Shutdown
      8. 9.4.8 Fault State and Power-Good
    5. 9.5 Programming
      1. 9.5.1 Serial Interface Description (TPS61280D/E)
      2. 9.5.2 Standard-, Fast-, Fast-Mode Plus Protocol
      3. 9.5.3 HS-Mode Protocol
      4. 9.5.4 TPS6128xD/E 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  I2C Registers, E2PROM, Write Protect
      4. 9.6.4  E2PROM Configuration Parameters
      5. 9.6.5  CONFIG Register [reset = 0x01]
      6. 9.6.6  VOUTFLOORSET Register [reset = 0x02]
      7. 9.6.7  VOUTROOFSET Register [reset = 0x03]
      8. 9.6.8  ILIMSET Register [reset = 0x04]
      9. 9.6.9  Status Register [reset = 0x05]
      10. 9.6.10 E2PROMCTRL Register [reset = 0xFF]
  11. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 TPS61281D with 2.5V-4.35 VIN, 1500 mA Output Current (TPS61280D with default I2C Configuration)
        1. 10.2.1.1 Design Requirement
        2. 10.2.1.2 Detailed Design Parameters
          1. 10.2.1.2.1 Inductor Selection
          2. 10.2.1.2.2 Output Capacitor
          3. 10.2.1.2.3 Input Capacitor
          4. 10.2.1.2.4 Checking Loop Stability
        3. 10.2.1.3 Application Performance Curves
      2. 10.2.2 TPS61282D with 2.5V-4.35 VIN, 2000 mA Output Current (TPS61280D with I2C Programmable)
        1. 10.2.2.1 Design Requirements
        2. 10.2.2.2 Detailed Design Procedures
        3. 10.2.2.3 Application Performance Curves
  12. 11Power Supply Recommendations
  13. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
    3. 12.3 Thermal Information
  14. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 第三方产品免责声明
    2. 13.2 接收文档更新通知
    3. 13.3 支持资源
    4. 13.4 Trademarks
    5. 13.5 静电放电警告
    6. 13.6 术语表
  15. 14Mechanical, Packaging, and Orderable Information
    1. 14.1 Package Summary

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订购信息
10.2.1.2.4 Checking Loop Stability

The first step of circuit and stability evaluation is to look from a steady-state perspective at the following signals:

  • Switching node, SW
  • Inductor current, IL
  • Output ripple voltage, VOUT(AC)

These are the basic signals that need to be measured when evaluating a switching converter. When the switching waveform shows large duty cycle jitter or the output voltage or inductor current shows oscillations, the regulation loop may be unstable. This is often a result of board layout and/or L-C combination.

As a next step in the evaluation of the regulation loop, the load transient response is tested. The time between the application of the load transient and the turn on of the P-channel MOSFET, the output capacitor must supply all of the current required by the load. VOUT immediately shifts by an amount equal to ΔI(LOAD) x ESR, where ESR is the effective series resistance of COUT. ΔI(LOAD) begins to charge or discharge COUT generating a feedback error signal used by the regulator to return VOUT to its steady-state value. The results are most easily interpreted when the device operates in PWM mode.

During this recovery time, VOUT can be monitored for settling time, overshoot or ringing that helps judge the converter’s stability. Without any ringing, the loop has usually more than 45° of phase margin. Because the damping factor of the circuitry is directly related to several resistive parameters (that is, MOSFET rDS(on)) that are temperature dependant, the loop stability analysis has to be done over the input voltage range, load current range, and temperature range.

The TPS6128xD series of step-up converters have been optimized to operate with a effective inductance in the range of 200 nH to 800 nH and with output capacitors in the range of 8 µF to 100 µF. The internal compensation is optimized for an output filter of L = 0.5 µH and CO = 15 µF.

Table 10-3 Component List
REFERENCE DESCRIPTION PART NUMBER, MANUFACTURER(1)
CIN 1.5μF, 6.3V, 0402, X5R ceramic GRM155R60J155ME80D
COUT 2 x 10μF, 6.3V, 0603, X5R ceramic 2 x GRM188R60J106ME84
L 470nH, 47mΩ, 2.5mm x 2.0mm x 1.2mm DFE252012CR470