CMOS IC
LC78637E
for Compact Disc Player Applications
Overview
The LC78637E combines audio CD RF signal processing, servo control, EFM signal processing, audio
signal processing, and a CDTEXT decoder in a single chip, enabling a system to be configured with very
few peripheral components. The RF signal processing block performs such functions as EFM signal
generation, error signal generation, and laser power control. The servo control block carries out A/D
conversion of focus error and tracking error signals from the RF signal processing block, and digitally
performs focus, tracking, sled, and spindle servo processing necessary for CD servo operation. The
functions of the EFM signal processing block cover EFM signal demodulation and synchronization
detection, protection, and interpolation, de-interleaving, and error detection and correction. The audio signal
processing block handles data interpolation/mute processing based on the error correction situation, and
incorporates an 8X over sampling filter, 1-bit DAC, and secondary LPF (differential amplifier). The status
and characteristics of each function block can be set, or ascertained by data reads, via the microcomputer
interface.
Playback functions
— Playback speed: 1X speed, 2X speed
— Jitter-free playback (VCEC)
— CD-R/W: 1X speed, 2X speed
— Simple CLV playback
RF processing block
— RF system: AGC, CD-R, R/W playback supported, peak hold, bottom hold
— Error system: Variable-balance TE signal generation, FE signal generation
— Detection: Track counting signal, jitter, flaws (black, mirror)
— Laser power control
— DC offset voltage cancellation
Servo control block
— Digital processing of tracking, focus, sled, and spindle servos
— Automatic adjustment functions: Focus gain, focus bias, focus offset, tracking gain, tracking offset,
tracking balance
— Use of Sanyo’s original high-performance servo control technology* to improve playability, covering
external vibration and playback of warped or eccentric discs
— Shock detection
— Interruption detection
* Robust control technology developed by Sanyo, offering remarkable ability to suppress vibration
and shocks, and to achieve tracking of warped or eccentric discs
EFM processing block
— Error detection and correction
— Built-in text decoder
(C1 = twofold, C2 = fourfold/twofold)
— EFM signal synchronization detection,
— Jitter margin: ± 13 frames
— DOUT output
protection, interpolation
Audio processing block
— Interpolation (4 interpolations)
— Digital attenuator
— Fadeout function
— Bilingual function
— Built-in de-emphasis filter
— Built-in secondary LPF for audio output
— DF and DAC clocks can be supplied externally
— 1-bit DAC (tertiary ∆ Σ noise shaper system)
— Built-in 8X oversampling digital filter