WM8602SEDSSLASHV datasheet(14/46 Pages) WOLFSON

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WM8602

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PP Rev 1.5 May 2004

DEVICE DESCRIPTION

INTRODUCTION

The WM8602 is a high-performance multi-channel Pulse-Width Modulation (PWM) digital power

amplifier controller. The device accepts up to 2 channels of audio in PCM input format, and outputs 2

PWM full-bandwidth channels, plus a PWM sub-woofer channel. The outputs are suitable for directly

driving integrated switching output stages available from a number of vendors. The device is also

compatible with discrete MOSFET output stages. In both cases, Wolfson Microelectronics offer

Reference Designs for complete PWM digital power amplifiers.

The WM8602 has a configurable input processor which accepts Stereo channels of PCM audio and

outputs Stereo or 2.1 outputs. The sub channel is generated from the filtered sum of the low

frequency components of the input data.

The device has a Bass Management function, which has low-pass and high-pass filters for feeding

the sub channel and main output channels. It also provides selectable boost for the LFE channel.

Each channel can be configured to drive either “large” full-range speakers or “small” satellite

speakers with limited bass capability.

A Tone Control function is provided, plus selectable high frequency equalisation to compensate for

different loudspeaker characteristics. Independent volume control is provided for all channels, with

comprehensive mute features.

A Dynamic Peak Compressor with programmable attack and decay times is included, which allows

headroom for tone control, bass management and extra digital gain to be provided, without clipping

occurring.

The device is controlled via a 2/3 wire serial interface. The interface provides access to all features

including channel selection, volume controls, mute, de-emphasis and power management facilities.

SIGNAL PATH

The WM8602 receives digital input data via a 2-channel digital audio interface. The data is processed

in turn by the Input Processor, Bass Management and Equalisation, Volume Control and Dynamic

Peak Compressors, Interpolation Filters, and PCM-PWM Converters, as shown in Figure 7. The

PWM signals are output via CMOS drivers.

Figure 7 Signal Processing Block Diagram

Volume Control / Dynamic

Peak Compressors

PCM - PWM Converter

Interpolation Filters

Input Processor

Bass Management and

Equalisation

CMOS Output

2 Channel Input

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