JAJSQ69B december   2015  – may 2023 TPS65265

PRODUCTION DATA  

  1.   1
  2. 特長
  3. アプリケーション
  4. 概要
  5. Revision History
  6. Device Comparison Table
  7. Pin Configuration and Functions
  8. 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 Typical Characteristics
  9. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Adjusting the Output Voltage
      2. 8.3.2  Mix PGOOD, PG_DLY Functions
        1. 8.3.2.1 Programmable PGOOD DELAY
        2. 8.3.2.2 Relay Control
      3. 8.3.3  Enable and Adjusting UVLO
      4. 8.3.4  Soft-Start Time
      5. 8.3.5  Power-Up Sequencing
        1. 8.3.5.1 External Power Sequencing
        2. 8.3.5.2 Automatic Power Sequencing
      6. 8.3.6  V7V Low Dropout Regulator and Bootstrap
      7. 8.3.7  Out of Phase Operation
      8. 8.3.8  Output Overvoltage Protection (OVP)
      9. 8.3.9  PSM
      10. 8.3.10 Slope Compensation
      11. 8.3.11 Overcurrent Protection
        1. 8.3.11.1 High-Side MOSFET Overcurrent Protection
        2. 8.3.11.2 Low-Side MOSFET Overcurrent Protection
      12. 8.3.12 Adjustable Switching Frequency
      13. 8.3.13 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Operation With VIN < 4 V (Minimum VIN)
      2. 8.4.2 Operation With EN Control
  10. 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 Output Inductor Selection
        2. 9.2.2.2 Output Capacitor Selection
        3. 9.2.2.3 Input Capacitor Selection
        4. 9.2.2.4 Loop Compensation
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 ドキュメントの更新通知を受け取る方法
    2. 10.2 サポート・リソース
    3. 10.3 Trademarks
    4. 10.4 静電気放電に関する注意事項
    5. 10.5 用語集
  12. 11Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ(パッケージ|ピン)
サーマルパッド・メカニカル・データ
発注情報

Adjustable Switching Frequency

The ROSC pin can be used to set the switching frequency by connecting a resistor to GND. The switching frequency of the device is adjustable from 250 kHz to 2.3 MHz.

To determine the switching frequency for a given ROSC resistance, use Equation 8 or the curve in Figure 8-10. To reduce the solution size one must set the switching frequency as high as possible, but tradeoffs of the supply efficiency and minimum controllable on time must be considered.

Equation 8. ƒosc (kHz) = 30975 × Rosc (kΩ)–0.889
GUID-672194BF-C46C-41C3-8650-20F099F28CD0-low.gifFigure 8-10 Switching Frequency versus ROSC

When an external clock applies to ROSC pin, the internal phase locked loop (PLL) has been implemented to allow internal clock synchronizing to an external clock between 250 kHz and 2.3 MHz. To implement the clock synchronization feature, connect a square wave clock signal to the ROSC pin with a duty cycle between 20% to 80%. The clock signal amplitude must transition lower than 0.4 V and higher than 2.0 V. The start of the switching cycle is synchronized to the falling edge of ROSC pin.

In applications where both resistor mode and synchronization mode are needed, the device can be configured as shown in Figure 8-11. Before an external clock is present, the device works in resistor mode and ROSC resistor sets the switching frequency. When an external clock is present, the synchronization mode overrides the resistor mode. The first time the ROSC pin is pulled above the ROSC high threshold (2.0 V), the device switches from the resistor mode to the Synchronization mode and the ROSC pin becomes high impedance as the PLL starts to lock onto the frequency of the external clock. TI does not recommend to switch from the synchronization mode back to the resistor mode because the internal switching frequency drops to 100 kHz first before returning to the switching frequency set by ROSC resistor.

GUID-2C1333BC-3D25-438E-B0A3-85AE239D5632-low.gifFigure 8-11 Works With Resistor Mode and Synchronization Mode