Service Manual guide

The IRAUDAMP4 reference design is an example of a two-channel 120 W half-bridge
Class D audio power amplifier. The reference design will demonstrate how to use the
IRS20955, implement protection circuits, and design an optimum PCB layout using the
IRF6645 DirectFET MOSFETs. The resulting design requires no heatsink for normal
operation (one-eighth of continuous rated power). The reference design contains all the
required housekeeping power supplies for ease of use. The two-channel design is
scalable, for power and the number of channels.


Applications
AV receivers
Home theater systems
Mini component stereos
Sub-woofers
Features
Output Power: 120 W x two channels,
Total Harmonic Distortion (THD) = 1%, 1 kHz
Residual Noise: 52 μV, IHF-A weighted, AES-17 filter
Distortion: 0.004% THD+N @ 60 W, 4 Ω
Efficiency: 96% @ 120 W, 4 Ω, single-channel driven, Class D stage
Multiple Protection Features: Over-current protection (OCP),
Over-voltage protection (OVP),
Under-voltage protection (UVP),
DC-protection (DCP),
Over-temperature protection (OTP)
PWM Modulator: Self-oscillating half-bridge topology with optional clock
synchronization