|[February 21, 2013]
Toshiba Develops Time-Domain Analog and Digital Mixed-Signal Processing Circuitry
TOKYO --(Business Wire)--
Corporation (TOKYO: 6502) today announced that it has developed
time-domain analog and digital mixed-signal processing circuitry with
the potential to replace general digital signal processing in error
correction. The technology cuts the gate count of the low-density
parity-check (LDPC) decoder used in error correction of NAND flash
memory by 38% and will support Toshiba (News - Alert) in enhancing cost
competitiveness. The circuit was introduced at the
International Solid-State Circuit Conference in San Francisco on
February 20, 2013.
With advances in capacity, error correction is more important than ever
in ensuring the reliability of NAND flash memories. Advanced error
correction with improved correction rates is also a must in wirless
communication. In both areas, LDPC code is one of the most promising
error correction codes.
The problem with LDPC decoder circuitry is that it uses probability
information in volumes that surpass that of the bit information utilized
in classic error correction techniques, resulting in a large gate count.
Efforts to overcome this include using an analog quantity, such as
voltage, to represent probability information. This reduces the wiring
required to represent information, as a single wire can contain
multi-bit analog information but only one bit of digital information.
However, this approach is impractical, as the large-scale system
required cannot be designed with widely used design automation tools.
There is also the problem of integrating analog-to-digital and
digital-to-analog converters, which are large and power hungry.
Toshiba's time-domain analog and digital mixed-signal processing uses
"time" to represent information. Like a voltage-based analog signal,
"time" can contain multi-bit information, but its interface circuits,
time-to-digital and digital-to-time converters, are smaller and consume
less power than ADC (News - Alert) and DAC. All the circuit elements are digital,
allowing use of standard design automation tools, can be easily applied
to large scale systems.
Toshiba has fabricated LDPC decoder and demonstrated that the gate count
is 38% lower than with general digital implementation.
Mr. Daisuke Miyashita, a specialist of Toshiba Center for Semiconductor
Research & Development who worked for the development said "We are going
to advance research and development of the proposed method, with the
objective of applying it to various systems, including LDPC decoders
that handle large volumes of information."
Toshiba is a world-leading diversified manufacturer, solutions provider
and marketer of advanced electronic and electrical products and systems.
Toshiba Group brings innovation and imagination to a wide range of
businesses: digital products, including LCD TVs, notebook PCs, retail
solutions and MFPs; electronic devices, including semiconductors,
storage products and materials; industrial and social infrastructure
systems, including power generation systems, smart community solutions,
medical systems and escalators & elevators; and home appliances.
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