Power Supply For Ultra High-Fidelity Audio Amplifier LME49810, LME49811, LME49830
This application note will cover the design of a ±72V unregulated power supply designed specifically for the LME49810, LME49811 and LME49830 high-fidelity audio amplifier modules. The output power of the modules are approximately 220W to 250W into 8Ω and 350W to 400W into 4Ω. Complete documentation for the amplifier modules can be found in the documents listed below. AN-1625 LME49810TB Ultra-High Fidelity, High-Power Amplifier Reference Design AN-1850 LME49830TB Ultra-High Fidelity, High-Power Amplifier Reference Design Although the power supply design is specific to the amplifier modules the concepts and circuit design may be used for any power supply purpose. The power supply is an unregulated design with an option to allow connection to either 120V or 240V mains. The design uses toroidal transformers, a fully integrated bridge, and various rail capacitors for ripple voltage reduction, noise suppression, and to act as high current reservoirs. Additional circuitry to control inrush current on power up and power up/ down Mute control are also included. A complete schematic, PCB views, and Bill of Materials are provided for the power supply design.