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Introduction

The IRAUDAMP18 reference design is a two-channel, 35W/ch half-bridge Class D audio power

amplifier with single power supply. This reference design demonstrates how to use the IR4312 IC

with single power supply, implement protection circuits, and design an optimum PCB layout using

PowIRaudio integrated Class D IC. This reference design does not require additional heatsink or fan

cooling for normal operation (one-eighth of continuous rated power).The reference design provides all

the required housekeeping power supplies for ease of use. The two-channel design is scalable for

power and the number of channels.

Applications



Docking station audio systems



PC audio systems



Musical instruments



Karaoke amplifiers



Game consoles



Powered speaker systems



Car audio amplifiers

Features

Output Power:

35W x 2 channels (4Ω load)

Multiple Protection Features:

Over-current protection (OCP), high side and low side

Over-voltage protection (OVP),

Under-voltage protection (UVP), high side and low side

Over-temperature protection (OTP)

PWM Modulator:

Self-oscillating half-bridge topology

Specifications

General Test Conditions (unless otherwise noted)

Notes / Conditions

Supply Voltages

18-31V

Load Impedance

2-4Ω

Resistive load

Self-Oscillating Frequency

400kHz

No input signal, Adjustable

Gain Setting

21.4dB

1Vrms input yields rated power

Electrical Data

Typical

Notes / Conditions

IR Devices Used

IR4312 PowIRaudio integrated Class D IC

Modulator

Self-oscillating, second order sigma-delta modulation, analog input

Power Supply Range

18-31V

Single power supply;

Output Power CH1-2: (1% THD+N)

26W

1kHz

Output Power CH1-2: (10% THD+N)

35W

1kHz

Rated Load Impedance

2-4Ω

Resistive load

Idling Supply Current

70mA

No input signal

Total Idle Power Consumption

2.2W

No input signal

Distortion

0.018%

THD+N @ 3W, 4Ω

Residual Noise

180

V

IHF-A weighted, AES-17 filter

Channel Efficiency

96%

Single-channel driven, 35W, Class D

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