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Si824xClassD-KIT
2 Rev. 0.2
3. Hardware Overview and Demo
3.1. Reference Design Board Architecture
The Silicon Labs Class D reference design architecture uses a phase-shift, self-oscillating modulation approach
that is capable of achieving far greater signal-to-noise ratio than clock driven amplifiers (see Figure 2). This self-
oscillating implementation eliminates the circuitry necessary to generate the triangle waveform. To keep the circuit
as simple as possible, a two-state, half-bridge is implemented and exemplifies the benefits of using the Si8241
Audio Gate Driver.
Figure 2. Block Diagram of Si8241-Based Class D Amplifier
3.2. Setting up the Class D Amplifier
Figure 3 illustrates connections necessary to power the Class D amplifier. The user will need the following items:
MP3 player (or equivalent line out audio source)
Audio Y-Cable (stereo male to Dual RCA Male)
±50 V supply capable of sourcing 3 Amps
±12 V supply capable of sourcing 500 mA
Two speakers (up to 150 W)
Silicon Labs Class D reference design board
Warning:
1. To protect the amplifier and speakers, before turning on the main power (the ±50 V supplies) to the amplifier, ensure that
the audio source from the MP3 player has its volume set to the lowest possible level.
2. The L-bracket can heat up to 80 °C and should be handled with care.