IEEE Solid-States Circuits Magazine - Winter 2022 - 26

For portable devices such as smartphones,
and for long-term operation
and carbon neutrality, the technology
commonly necessary is low-power electronics.
At present, the importance of
low-power technology has become a
recognized in the world, but this was
not the case until the middle of the
1990s. The first priority for IC technology
is high performance, especially
high speed, and the concern
with low power consumption was
thin. However, low-power technology
is important for the realization
of consumer portable equipment and
long battery life.
In 1994, I gave an invited talk on
low-power IC design at the 1994 IEEE
VLSI Circuits Symposium [8], and the
paper was published in IEEE Journal of
Solid-State Circuits in 1994 [9]. On the
low power of the consumer portable
equipment, both the digital and analog
circuits were mentioned, and it was
pointed out that the low power of the
whole system is important. In the same
year, I wrote the article " White Paper
for Low Power LSI Technology: Challenge
Toward 1 Milliwatt Operation, "
published by Nikkei BP [10], and pointed
out the importance of not only circuits
but also systems and architectures to
reduce power consumption.
In 1995, I organized and cochaired
the Low Power Electronics Workshop
with Dr. Kubo from Hitachi and R.-H.
Yan from AT&T Bell Labs. Aside from
ADCs, our technological development
on low-power electronics was
a low-power DSP using an adaptive
power supply [see Figure 8(a)] [11]
and an on-chip power supply [12]. A
low-power DSP using the power supply
control to the DSP core with an
on-chip dc-dc power supply for wireless
communication was developed.
The replica circuit is used to find the
minimum operating voltage that can
satisfy the given processing speed
and to reduce the power dissipation
by giving the voltage from the onchip
dc-dc power supply.
Figure 8(b) presents the wristwatchtype
Personal Handyphone System
(PHS) equipped with the DSP. This
wristwatch PHS was used for communication
among officers at the 1998 Winter
Olympics in Nagano, Japan.
A low-power, wireless personal
digital assistant using Fully Depleted
Silicon on Insulator (FD-SOI) that
has excellent low-voltage and lowpower
characteristics was developed
by members of several companies
including Panasonic and universities
centered on Nippon Telegraph
and Telephone Corporation (NTT) for
four years, beginning in 2000 [13]. It
is possible to transmit and receive
images using power generated by
temperature difference in body temperature
using the Peltier effect. This
technology was summarized in our
published in [14].
(a)
(b)
FIGURE 8: (a) A low-power DSP using an adaptive power supply [11], [12] and (b) a wristwatch-type
PHS for the 1988 Winter Olympics in Nagano, Japan.
VariableGain
Amplifier
DVD,
HDD
Analog
Filter
ADC
7 b, 400 MS/s
VoltageControlled
Oscillator
(a)
Clock
Recovery
Digital
FIR
Filter
Viterbi
Error

IEEE Solid-States Circuits Magazine - Winter 2022

Table of Contents for the Digital Edition of IEEE Solid-States Circuits Magazine - Winter 2022