Download High-Capacitance Supercapacitors Suit to Broade

TECH | FOCUS
High-Capacitance Supercapacitors
Suit to Broader Application Fields
New product: DMF series 1000mF
14 × 30 × 3.7mm
Part No.
Conventional product: DMF series 470mF
14 × 21 × 3.2mm
Rated
ESR
Nominal
Operating
voltage (@1kHz) capacitance temperature range
DMF4B5R5G105M3DTA0 5.5V
40mΩ
1,000mF
-40°C - 70°C
DMF3Z5R5H474M3DTA0 5.5V
45mΩ
470mF
-40°C - 70°C
Photo: DMF Series EDLC products
Typical
Supercapacitor
Usage
The low-ESR
and high-capacitance DMF Series
is used as an auxiliary power supply
for assistance during peak output or
backup. It can also
be used in various devices, for example,
it can reduce the load of a battery or
serve as a maintenance-free power supply in combination with a power generation element. It can contribute to reducing the size of a power supply, and to the
implementation of higher functionality
and energy saving.
Output
Auxiliary power supply for peak
output (Fig. 1)
When the DMF Series is used as an
auxiliary power supply during peak output, it is highly possible to reduce the
size of power supply units, add a higher
output function, and improve the performance. A sample application includes
as peak-output auxiliary power supply
for light-emitting diodes (LEDs), compact DC motor devices, gas and water
smart meters, and Remote Keyless Entry
(RKE) system.
EDLC
Load
converter
Battery
Time
Power
supply
EDLC
Fig. 1: EDLC as auxiliary power supply for
peak output
Auxiliary power supply for backup
(Fig. 2)
The DMF Series makes it possible to
achieve a high-output backup function
in a confined space by taking full advantage of its features such as long life, as
well as lower ESR and size smaller than
a battery. In particular, it can be used as
a memory backup for solid-state drives
(SSD) and programmable logical controllers (PLC), and last gasp of communication devices.
Power shutdown
Output
M
urata Manufacturing Co.,
Ltd. has started mass production of the DMF Series supercapacitors, also
called as electrical double-layer capacitors (EDLCs), that feature low equivalent series resistance (ESR) and high
capacitance (1,000mF) from Oct. 2014.
A supercapacitor is an electricity storage device that has higher capacitance
than conventional capacitors such as
ceramic capacitors and electrolytic
capacitors, has lower ESR than batteries, and has long life. Among various
supercapacitors, Murata’s DMF Series
has the industry's lowest ESR level and
can discharge electricity with a large
output of several tens of watts. When
Murata’s DMF Series is used as an
auxiliary power supply for assistance
during peak output or backup, the size
of batteries and power supply units can
be made smaller, energy loss can be reduced, and a high output function can
be achieved. Murata has added a highcapacitance supercapacitor of 1,000mF
to the DMF Series lineup besides the
conventional 470mF supercapacitor
products. This new DMF Series product enables peak output assistance
and backup for even longer hours, and
therefore there is high expectation for
its use in various devices. This article
introduces some applications that take
maximum advantage of DMF Series supercapacitors.
Power
supply
Power shutdown
Load
EDLC
PS
EDLC
Time
Fig. 2: EDLC as auxilliary power supply for
backup
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TECH | FOCUS
Battery load reduction (Fig. 3)
The low-ESR and high-capacitance
features of the DMF Series can be used
to improve device functions and stabilize
operations by leveling large fluctuations
of a power voltage line. For example, it
can be used as a power supply for audio
equipment, various communication devices, portable printers, and security and
health-care devices.
Voltage
Battery+EDLC
Load
Battery
Battery only
EDLC
Time
Fig. 3: Battery load reduction
Energy storage device (Fig. 4)
The DMF Series can serve as a maintenance-free power supply by making
the most of supercapacitor’s long-life
feature in combination with various
power generation elements. The DMF
Series can also minimize energy loss
caused by an unstable input and high
output by taking advantage of its lowESR feature. For example, it can be used
a power supply for a sensor network
system and the Internet of Things (IoT)
device using energy harvesting.
Fig. 5: Application example of EDLC for SSD backup
CH1: Input signal
CH3: Load current (use of current probe)
Sound source
(stereo output)
R+
DC power supply
(Stabilized power
supply or Battery)
Output
EDLC
Speaker
Audio signal
Power
supply line
Unstable input
Class D
amplifier
stereo
specifications
R-
L+
L-
Load
Harvester
EDLC
Time
Inserting EDLC
Fig. 4: Energy storage device
Supercapacitor Sample
Applications and Effects
For SSDs
When used as backup for enterprise
SSDs (SAS, SATA, and PCIe) (Fig. 5),
the DMF Series contributes to space
saving by reducing the required number
of tantalum capacitors and aluminum
electrolytic capacitors. The energy that
can be stored in a Murata supercapacitor 470mF product is 100 times or higher
than high-capacitance tantalum capacitors. For example, when discharging
is performed from 5.5 to 2.0V at 10W,
supercapacitor can supply backup power
for approximately 1sec.
For battery-operated audio devices
(Fig. 6)
Supercapacitors are employed to sta34
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AEI May 2015
Polymer capacitor
220 F
Approx.
700mAp-p
EDLC
350mF
Approx.
250mAp-p
Fig. 6: Application example of EDLC for audio amplifier
bilize the power supply of high-end portable audio devices (sound quality improvement). As a result, they contribute
to sound quality improvement by stabilizing the power supply line.
For gas, water smart meters (Fig. 7)
When the DMF Series is used as an
auxiliary power supply for communications and valve opening and closing, it
contributes to extending the 15-year life
of a primary battery to 20 years. The
DMF Series can utilize the energy stored
in a battery efficiently because it has low
ESR and low loss in a low temperature
environment.
For LEDs (Fig. 8)
Supercapacitors used in LED flash of
digital still cameras and digital video
cameras and LED beacon of fire alarms
contribute to improving functions by
enabling LED light emission through
the high current. Regarding the supercapacitor application for flash, when
LEDs are used for camera flash, they
can provide longer life and the size
of the circuit for flash function can be
reduced. Such an application also can
provide unique functions, for example,
making it possible to change the light
emission time and brightness more
flexibly and perform continuous shooting function.
Enables discharge for approximately
1sec with a potential difference from 5.5
to 2.5V when a DMF Series 1,000mF
product is discharged at 4A.
<After 15 years, 35ºC, 3.6V>
2W Constant Power Discharge by temperaure
Power supply
Output assist by
EDLC
Power
management
Load
3.8
P/N: DMF4B5R5G105M3DTA0
3.6
3.6V
DMF
series
Voltage(V)
Battery
(Li-SOCl2, etc.)
Balancing resistor
3.4
Communication
function
Metering
function
Power
management
3.2
3.0
2.8
-30
2.6
25
2.4
M
2.2
Motor function
2.0
0.0
0.5
1.0
1.5
2.0
Time(sec)
Other functions (display, etc.)
Fig. 7: Application example of EDLC for smart meters
Vout ( - 8V) or Vout ( - 5.5V)
Vin
Constant Current Discharge(@25ºC)
(Charge Voltage: 5.5V)
Vedlc ( - 5.5V)
Lithium-ion
rechargeable
battery, etc.
LEDs
Murata’s EDLC
series
or
AS3630
TPS6130*
SCF04
Series
connection
AS3630
Parallel
connection
TPS6130*
SCF04
Capacitor Voltage(V)
LED
FLASH
Driver
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
1A
2A
4A
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
Time (sec.)
Fig. 8: Application example of EDLC for LED flash
Conclusion
This article has introduced some applications and application examples of
low-ESR and high-capacitance supercapacitors that make the most of their ad-
vantages. Murata continues to work on
developing even smaller products with
lower ESR so that the devices can have
higher functionality, smaller size, and
energy-saving features.
About This Article:
The author, Atsushi Kawashima, is
from the Planning and Sales Promotion
Section, High Performance Power Device
Dept. of Murata Manufacturing Co., Ltd.
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