ZHCSI48B September   2017  – June 2018 TPS560430

UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.  

  1. 特性
  2. 应用
  3. 说明
    1.     Device Images
      1.      简化原理图
      2.      效率与输出电流间的关系 VOUT = 5V,1100kHz,PFM
  4. 修订历史记录
  5. Device Comparison Table
  6. Pin Configuration and Functions
    1.     Pin Functions
  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 Switching Characteristics
    8. 7.8 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Fixed Frequency Peak Current Mode Control
      2. 8.3.2 Adjustable Output Voltage
      3. 8.3.3 Enable
      4. 8.3.4 Minimum ON-Time, Minimum OFF-Time and Frequency Foldback
      5. 8.3.5 Bootstrap Voltage
      6. 8.3.6 Over Current and Short Circuit Protection
      7. 8.3.7 Soft Start
      8. 8.3.8 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Active Mode
      3. 8.4.3 CCM Mode
      4. 8.4.4 Light-Load Operation (PFM Version)
      5. 8.4.5 Light-Load Operation (FPWM Version)
  9. Application 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 Custom Design With WEBENCH® Tools
        2. 9.2.2.2 Output Voltage Set-Point
        3. 9.2.2.3 Switching Frequency
        4. 9.2.2.4 Inductor Selection
        5. 9.2.2.5 Output Capacitor Selection
        6. 9.2.2.6 Input Capacitor Selection
        7. 9.2.2.7 Bootstrap Capacitor
        8. 9.2.2.8 Under Voltage Lockout Set-Point
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Compact Layout for EMI Reduction
      2. 11.1.2 Feedback Resistors
    2. 11.2 Layout Example
  12. 12器件和文档支持
    1. 12.1 器件支持
      1. 12.1.1 开发支持
        1. 12.1.1.1 使用 WEBENCH® 工具创建定制设计
    2. 12.2 文档支持
      1. 12.2.1 相关文档
    3. 12.3 接收文档更新通知
    4. 12.4 社区资源
    5. 12.5 商标
    6. 12.6 静电放电警告
    7. 12.7 术语表
  13. 13机械、封装和可订购信息

封装选项

请参考 PDF 数据表获取器件具体的封装图。

机械数据 (封装 | 引脚)
  • DBV|6
散热焊盘机械数据 (封装 | 引脚)
订购信息

Minimum ON-Time, Minimum OFF-Time and Frequency Foldback

Minimum ON-time, TON_MIN, is the smallest duration of time that the HS switch can be on. TON_MIN is typically 60 ns in the TPS560430. Minimum OFF-time, TOFF_MIN, is the smallest duration that the HS switch can be off. TOFF_MIN is typically 100 ns. In CCM operation, TON_MIN and TOFF_MIN limit the voltage conversion range without switching frequency foldback.

The minimum duty cycle without frequency foldback allowed is

Equation 2. DMIN = TON_MIN X fSW

The maximum duty cycle without frequency foldback allowed is

Equation 3. DMAX = 1 - TOFF_MIN X fSW

Given a required output voltage, the maximum VIN without frequency foldback can be found by

Equation 4. TPS560430 slvse22-equation-4.gif

The minimum VIN without frequency foldback can be calculated by

Equation 5. TPS560430 slvse22-equation-5.gif

In the TPS560430, a frequency foldback scheme is employed once the TON_MIN or TOFF_MIN is triggered, which may extend the maximum duty cycle or lower the minimum duty cycle.

The on-time decreases while VIN voltage increases. Once the on-time decreases to TON_MIN, the switching frequency starts to decrease while VIN continues to go up, which lowers the duty cycle further to keep VOUT in regulation according to Equation 2.

The frequency foldback scheme also works once larger duty cycle is needed under low VIN condition. The frequency decreases once the device hits its TOFF_MIN, which extends the maximum duty cycle according to Equation 3. In such condition, the frequency can be as low as about 133 kHz minimum. Wide range of frequency foldback allows the TPS560430 output voltage stay in regulation with a much lower supply voltage VIN, which leads to a lower effective drop-out.

With frequency foldback, VIN_MAX is raised, and VIN_MIN is lowered by decreased fSW.

TPS560430 D012_SLVSE22.png
VOUT = 1 V fSW = 1.1 MHz
Figure 16. Frequency Foldback at TON_MIN
TPS560430 D011_SLVSE22.png
VOUT = 5 V fSW = 1.1 MHz
Figure 17. Frequency Foldback at TOFF_MIN