SNAS491C February   2010  – January 2025 LM48580

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  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: VDD = 3.6 V #GUID-238D0643-98EF-4676-B2E1-A584A5DF74F7/SNAS491599
    6. 5.6 Typical Performance Characteristics
  7.   Parameter Measurement Information
  8. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Class H Operation
      2. 6.3.2 Properties of Piezoelectric Elements
      3. 6.3.3 Differential Amplifier Explanation
      4. 6.3.4 Thermal Shutdown
      5. 6.3.5 Gain Setting
    4. 6.4 Device Functional Modes
      1. 6.4.1 Shutdown Function
  9. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
        1. 7.2.1.1 Proper Selection of External Components
          1. 7.2.1.1.1 Boost Converter Capacitor Selection
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Boost Converter Output Capacitor Selection
          1. 7.2.2.1.1 Inductor Selection
          2. 7.2.2.1.2 Diode Selection
        2. 7.2.2.2 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  10. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Development Support
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Community Resources
    4. 8.4 Trademarks
  11. 9 Revision History
  12. 10Mechanical, Packaging, and Orderable Information

6.3.1 Class H Operation

Class H is a modification of another amplifier class (typically Class B or Class AB) to increase efficiency and reduce power dissipation. To decrease power dissipation, Class H uses a tracking power supply that monitors the output signal and adjusts the supply accordingly. When the amplifier output is below 3 VP-P, the nominal boost voltage is 6 V. As the amplifier output increases above 3 VP-P, the boost voltage tracks the amplifier output as shown in Figure 6-1. When the amplifier output falls below 3 VP-P, the boost converter returns to its nominal output voltage. Power dissipation is greatly reduced compared to conventional Class AB drivers.

LM48580 Class H OperationFigure 6-1 Class H Operation