Robust design for Class D audio amp

An International Rectifier product story

Edited by the Electronicstalk editorial team Dec 14, 2004

A new audio amplifier reference design offers a complete and robust solution for designers looking to move up to the performance potential of a Class D audio amplifier in a smaller footprint.

The IRAUDAMP1 Class D audio amplifier reference design from International Rectifier is a complete and robust solution for designers looking to move up to the performance potential of a Class D audio amplifier in a smaller footprint.

This latest reference design features the 200V-rated IR2011S high-speed gate driver IC, which drives a pair of IRFB23N15D HEXFET MOSFETs for each channel in the power stage to provide the amplified audio PWM (pulsewidth modulated) waveform.

The reference design is a complete analogue input, Class D audio power amplifier with 500W + 500W peak stereo output into 4ohm.

The IRAUDAMP1 is based on a self-oscillating PWM modulator for the lowest component count and a robust design, with protection functions and housekeeping power supplies to simplify use.

This reference design is intended to demonstrate how to use the IR2011S, implement protection circuit features and design an optimum PCB layout.

Performance highlights of the IRAUDAMP1 include: total harmonic distortion plus noise of 0.008% at 1kHz, 100W, 4ohm; high efficiency of 93% at 350W, 1kHz, 4ohm; and a wide operating supply voltage range +/-25 to 60V.

Protection circuits include overvoltage (OVP) and overcurrent (OCP) protection.

In addition, DC voltage output protection prevents speaker damage from DC current.

The IR2011 200V-rated high- and low-side MOSFET driver IC is designed for 100-1000W Class D audio amplifier circuits.

Housed in an 8-pin DIP or SO-8 package, it has a maximum ambient temperature rating of 125C, which improves safety margins compared with similar devices rated at 85C.