JAJSV09 July   2024 LMG2100R026

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
  7. 6 Parameter Measurement Information
    1. 6.1 Propagation Delay and Mismatch Measurement
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Control Inputs
      2. 7.3.2 Start-Up and UVLO
      3. 7.3.3 Bootstrap Supply Voltage Clamping
      4. 7.3.4 Level Shift
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 VCC Bypass Capacitor
        2. 8.2.2.2 Bootstrap Capacitor
        3. 8.2.2.3 Slew Rate Control
        4. 8.2.2.4 Power Dissipation
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Examples
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 サポート・リソース
    4. 9.4 Trademarks
    5. 9.5 静電気放電に関する注意事項
    6. 9.6 用語集
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Package Information
    2. 11.2 Mechanical Data

8.2.2.2 Bootstrap Capacitor

The bootstrap capacitor provides the gate charge for the high-side gate drive, dc bias power for HB UVLO circuit, and the reverse recovery charge of the bootstrap diode. The required bypass capacitance can be calculated using Equation 2.

Equation 2. CBST = (QG + QRR + IHB × tON(max)) / ΔV

where

  • IHB is the quiescent current of the high-side gate driver
  • tON(maximum) is the maximum on-time period of the high-side gate driver
  • QRR is the reverse recovery charge of the bootstrap diode
  • QG is the gate charge of the high-side GaN FET
  • ΔV is the permissible ripple in the bootstrap capacitor (< 100mV, typical)

A 0.1µF, 16V, 0402 ceramic capacitor is suitable for most applications. Place the bootstrap capacitor as close as possible to the HB and HS pins.