JAJSVT7 December   2024 LMG5126

ADVANCE INFORMATION  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Timing Requirements
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Device Configuration
      2. 6.3.2 Switching Frequency and Synchronization (SYNCIN)
      3. 6.3.3 Dual Random Spread Spectrum (DRSS)
      4. 6.3.4 Operation Modes (BYPASS, DEM, FPWM)
    4. 6.4 Device Functional Modes
      1. 6.4.1 Shutdown State
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Feedback Compensation
    2. 7.2 Typical Application
      1. 7.2.1 Application
      2. 7.2.2 Design Requirements
      3. 7.2.3 Detailed Design Procedure
        1. 7.2.3.1 Determining the Duty Cycle
        2. 7.2.3.2 Timing Resistor RT
        3. 7.2.3.3 Vout Programming
        4. 7.2.3.4 Inductor Selection Lm
        5. 7.2.3.5 Output Capacitor Cout
      4. 7.2.4 Application Curves
        1. 7.2.4.1 Efficiency
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 ドキュメントの更新通知を受け取る方法
    2. 8.2 サポート・リソース
    3. 8.3 Trademarks
    4. 8.4 静電気放電に関する注意事項
    5. 8.5 用語集
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information
    1. 10.1 Package Option Addendum
    2. 10.2 Tape and Reel Information
    3. 10.3 Mechanical Data

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）
  • VBT|22
サーマルパッド・メカニカル・データ

6.3.4 Operation Modes (BYPASS, DEM, FPWM)

The device supports bypass mode, forced PWM (FPWM) and diode emulation mode (DEM) operation. The mode can be changed on the fly and is set by the MODE-pin. Bypass mode is automatically activated for VOUT < VI. In multi-device stacked operation all devices must use the same mode.

The device operation mode is set to DEM for VMODE < 0.4V and to FPWM for VMODE > 1.2V.

Table 6-4 Mode-pin Settings
Operation Mode MODE-pin
DEM VMODE < 0.4V
FPWM VMODE > 1.2V

Details about the different operation modes are described in table Table 6-5.

Table 6-5 Operation Modes
Operation Mode Description
BYPASS VI is connected to VOUT (no regulation) while current flow from VOUT to VI is prevented for DEM selection and limited to VNCLTH for FPWM selection.
DEM Current flow from VOUT to VI is prevented. The SW-pin voltage is monitored during the high-side on time and the high-side switch is turned off when the voltage falls below the zero current detection threshold VZCD. This improves light load efficiency.
FPWM Converter keeps switching also for light load with fixed frequency in continuous conduction mode (CCM) for best light load transient response.

The device enters and exits Bypass mode when the conditions in table Table 6-6 are met.

Table 6-6 Bypass Mode Entry, Exit
Operation Mode Bypass Conditions
DEM / FPWM Entry VOUT < VI − 100mV and
VCOMP < VCOMP-MIN + 100mV
DEM Exit VCOMP > VCOMP-MIN + 100mV
||
((VCSP1 − VCSN1) < VZCD_BYP || (VCSP2 − VCSN2) < VZCD_BYP)
FPWM Exit VCOMP > VCOMP-MIN + 100mV
||
((VCSP1 − VCSN1) < VNCLTH || (VCSP2 − VCSN2) < VNCLTH)
LMG5126 Bypass Mode Entry, Exit Figure 6-3 Bypass Mode Entry, Exit