LOW-POWER PROCESSORS AND SYSTEMS ON CHIPS

zhang1998

LOW-POWER PROCESSORS AND SYSTEMS ON CHIPS
Christian Piguet
A CRC title, part of the Taylor & Francis imprint, a member of the
Taylor & Francis Group, the academic division of T&F Informa plc.
Boca Raton London New York
CSEM
Neuch^atel, Switzerland

The present book is a part of the book “Low-Power Electronics Design,” edited by Christian Piguet,
published in November 2004. It contains only the chapters that describe the design of low-power
processors and systems-on-chips from microprocessors, dsp cores, reconfigurable processors, memories,
systems-on-chip issues, applications such as ad hoc networks and finally embedded software. All the
other chapters, describing microelectronics technologies, transistor models, logic circuits and CAD tools,
are also included in another smaller book entitled “Low-Power CMOS Circuits: Technology, Logic Design
and CAD Tools.”
The goal of the present book “Low-Power Processors and Systems on Chips” is to cover all the aspects
of the design of low-power microprocessors in deep submicron technologies. Today, the power consumption
of microprocessors is considered as one of the most important problems for high-performance chips
as well as for portable devices. For the latter, it is due to the limited cell battery lifetime, while it is the
chip cooling for the first case. As a result, for any chip design, power consumption has to be taken into
account very seriously. Before 1993–1994, only speed and silicon area were important in the design of
integrated circuits, and power consumption was not an issue. Just after, it was recognized that power
consumption has to be taken into account as a main design parameter. Many papers and books were
written to describe all the first design methodologies to save power limited to circuit design. However,
today, we have to cope with many new problems implied by very deep submicron technologies, such as
leakage power, interconnect delays and robustness.
Today, we are close to designing one billion transistor microprocessor chips, down to 0.10
μ
m and
below, supplied at less than half a volt and working at some GHz. This is due to an unexpected evolution
of the microelectronics technologies and to very innovative microprocessor architectures. This evolution
is not yet at its end, so the next decade will also see some spectacular improvements in the design of
microprocessor circuits. However, it is sure that the microprocessor architecture evolution is not always
a revolution, but as pointed out by:
“I was greatly amused few years ago — when companies were introducing pipelined microprocessors
— to learn that RISC technology enabled pipelining. That this could be responsible for pipelining,
which has existed for more than 30 years, illustrates the amnesia present in computer engineering”