Supercapacitors Extend Operating Life of Battery-Powered Devices

Supercapacitors are special capacitors designed with high stored energy densities, allowing them to serve as reserve power sources, or even primary power, in portable and battery-powered systems.

 

Supercapacitors can provide standalone power for smart meters. Image used courtesy of Kyocera

 

Newly released by Kyocera AVX, the Gen II PrizmaCap SCP 2.5V supercapacitor is rated for operation up to 2.5 V and features a very low equivalent series resistance. It is ideal for battery-powered applications, such as wearables and handheld electronics,  requiring periodic high power pulses, frequent primary battery charge and discharge cycles, or the need to extend device operating life.

 

Gen II PrizmaCap 2.5V SCP supercapacitor. Image used courtesy of Kyocera

 

Littelfuse has introduced the LS0502SCD33 eFuse Super Capacitor Protection IC, the latest of its family of eFuse protection ICs. The chip is designed to manage the charge and discharge cycles of supercapacitors for backup power and similar applications. 

Combined with supercapacitors, the LS0502SCD33 can accommodate operating voltages above 3 V and has a wider operating temperature range than lithium-ion battery-based power backup solutions.  

 

Supercapacitors

Supercapacitors are special-purpose capacitors designed with high energy and power densities. They can back up a system’s primary or secondary battery or as a standalone power source, such as in smart meters. 

In addition to providing backup power, supercapacitors can also help meet peak power demands that might exceed the capabilities of the primary supply. Working in conjunction with the primary supply, they can also extend the operating life of a device.  

A supercapacitor's capacitance and voltage ratings help define its energy storage capabilities. Higher capacitance and voltage ratings mean a supercapacitor can store more charge (energy), with the size of the supercapacitor defining its energy density.     

Supercapacitors have a longer cycle life, faster charge/discharge cycles, and a better temperature range than batteries.  

 

Capacitance and voltage define energy storage capacity. Image used courtesy of Arrow

 

PrizmaCap SCP 2.5 V Supercapacitors

Compared with AVX’s other supercapacitor offerings, the PrizmaCap 2.5V SCP series features a low package profile (3.4 mm for 20 F-rated devices) and a wide operating temperature range (-25°C to +65°C at 2.5 V). The device packages are surface mountable with fixed-position terminals. 

The PrizmaCap SCP series comprises three models with improvements over the Gen I series, including capacitance ratings up to 20 F and an energy storage density as high as 3.47 Wh/kg. 

Target applications for the new supercapacitors include medical devices, tablets, Internet of Things (IoT) devices, virtual reality wearables, handheld electronics, and power peripherals.

 

Managing Supercapacitor Backup Power

The LS0502SCD33 supercapacitor protection chip from Littelfuse is designed to manage the interface between a device’s main supply and its supercapacitor backup energy source. The new IC is designed specifically for platforms that must operate in harsh environments where lithium-ion batteries are not a viable backup power solution due to their limited temperature range. 

 

LS0502SCD33 eFuse Super Capacitor Protection IC. Image used courtesy of Littelfuse

 

The LS0502SCD33 sits at the interface between the nominal system supply system load and reserve energy supercapacitor bank. The IC monitors the input supply, and when it detects that the supply voltage has dropped below its usable threshold, it switches supply power to the supercapacitors. 

Once main power is restored, the supercapacitors are disconnected from the load and can be re-charged via an integrated linear charger at up to 300 mA.

Provided in a 3 mm x 3 mm surface-mount DFN package, the LS0502SCD33 accommodates voltages above 5 V and can provide up to 2 A of discharge current from the supercapacitors.  

 

LS0502SCD33 functional schematic. Image used courtesy of Littelfuse

 

Target applications for the LS0502SCD33 include supercapacitor backup power for automotive dashboard cameras, smart meters, IoT devices, handheld industrial tools, and similar battery-powered devices that can be subject to potentially harsh operating environments.  

 

Supercapacitor Research

The capabilities of supercapacitors continue to evolve through advanced research. A research team from the Department of Instrumentation and Applied Physics (IAP) and the Indian Institute of Science (IISc) recently developed a novel and highly dense supercapacitor technology that can expand the application space for supercapacitors. 

 

Ultra-micro supercapacitor using FETs. Image used courtesy of Indian Institute of Science

 

The technology uses Field Effect Transistors (FETs) as charge collectors instead of the metallic-oxide-based electrodes used in traditional supercapacitor designs to achieve high energy densities.