IEEE Solid-State Circuits Magazine - Winter 2016 - 52

Table 1. THe power converTer caTegory.
dc-dc/ac-dc

Switching converter

Voltage gain
(VOUT /VIN)

Inductor
Capacitor
Switching device

Capacitor
Switching device

Boost converter

Voltage multiplier or charge pump

Buck converter

Fractional regulator

Table 2. a brief HisTory of THe sc volTage mulTiplier.
year

auTHor(s)

Topology

experimenTal
or THeoreTical

reference

1914

Greinacher

Doubler

Experimental

[1] Phys. Zeit.

1923

Marx

Parallel to
serial

Experimental

[2] German patent

1932

Cockcroft-
Walton

Ladder

Experimental

[3] Proc. Royal.
Soc.

1958

Kilby

Invention of IC

1971

Brugler

Serial-parallel

Theoretical

[5] JSSC

1973

Falkner

Parallel

Theoretical

[6] Elec. Lett.

[4] U.S. Patent

1976

Dickson

Parallel

Experimental

[7] JSSC

1991

Ueno et al.

Fibonacci

Experimental

[8] ISCAS

1995

Cernea

Theoretical

[9] U.S. Patent

V1 = VIN
0V

Phase 1

VIN
2Q

VIN

Phase 2

VOUT

V1 = 2VIN
D2
Q

VIN
0V

VOUT_MAX = 2VIN
VOUT

and the SC converter, as shown in
Table 1. The switching converter
is composed of one or more inductors, one or more capacitors, and
several switching devices. The SC
convertor is composed of one to
many capacitors and one to many
switching devices. The differences
are 1) with or without inductors
and 2) single or many stages. Presently, the degree of integration is
all components except for inductor
for switching converter whereas all
components for SC. This is because
the inductance of an integrated
inductor is much smaller than the
value required for generating a high
voltage when the silicon area is limited. This concentrates on SC voltage multipliers or charge pumps.
Table 2 summarizes representative two-phase clock SC voltage multipliers. Grenacher is known as an
inventor of the so-called SC voltage
doubler in 1914 [1]. Marx developed
a pulse power generator for the R&D
of lightning in 1923 [2]. Cockcroft
and Walton built a voltage multiplier for a particle accelerator with
a dc voltage gain greater than two
in 1932 [3]. After Kilby invented the
IC in 1958 [4], Brugler [5], Falkner
[6], and Dickson [7] have realized
the integration of SC voltage multiplier in ICs. Another direction was
how the number of discrete capacitors and switching devices could be
reduced for small form factor and
low cost for high power applications.
Other types of circuit topology that
have been developed by Ueno et al.
[8] and Cernea [9] are also described
in this article.

Figure 1: an sc voltage doubler [1].

performance such as output voltage current and power efficiency.
There have been also several design
innovations in switching circuits
to enable to work at extremely low
voltages. This article shows state
of the art for switching circuits for
both dc-dc and ac-dc voltage multipliers and their applications as well.
There will be three parts to this
article series:

W I N T E R 2 0 16

■

Part 1, detailing the history of the
SC voltage multiplier
Part 2, fundamentals of charge
pump
Part 3, state-of-the-art switching
circuits and applications.

A Brief History of
the SC Voltage Multiplier
Voltage converters are categorized
into two groups, the switching converter

IEEE SOLID-STATE CIRCUITS MAGAZINE

Greinacher SC Voltage
Doubler (1914) Figure 1
To generate 200-V dc from 110-V
ac for an ionometer for measuring
the intensity of ionizing radiation
in 1914, Greinacher built a voltage
doubler, using an ac power source,
one capacitor, and two diodes, as
shown in Figure 1 [1]. There are two
phases: charging the capacitor from
the power source in phase 1 and discharging the capacitor to the output

Table of Contents for the Digital Edition of IEEE Solid-State Circuits Magazine - Winter 2016