Intermittent short-term power outages caused by local storms or other transient behavior can play havoc with computer-based systems. A power supply with ride-through capability provides power for a limited time during the outage. The LTC3350 announced recently by Linear Technology Corp is a high current backup controller and system monitor for power supplies using supercapacitors for ride-through energy storage.
It controls and balances the charge stored on up to four series connected supercapacitors and can handle 4.5V to 35V input voltage and over 10A of charge/backup current. A 14-bit analog-to-digital converter monitors both the input and output voltage and current. The chip uses a synchronous step-down controller to drive external N-channel MOSFETs for constant current/voltage charging of the capacitor stack allowing up to 5 V per cell. When backup is needed the step-down converter operates in reverse as a synchronous step-up DC/DC converter, drawing power from the supercapacitor stack to supply back-up power.
The LTC3350 Supercap Ride-through Controller – [Link]
Stephen Evanczuk writes:
Energy-microharvesting applications such as wireless sensor nodes require periodic bursts of power well beyond that available in steady state from most ambient sources. In this respect, supercapacitors offer performance characteristics that are well suited for energy-harvesting environments. By combining supercapacitors with appropriate power and charge management circuitry, and using specialized devices from manufacturers including Linear Technology, Maxim Integrated Products, and Texas Instruments, engineers can exploit microharvesting techniques in applications with demanding peak power requirements.
Power Management ICs Simplify Integration of Supercapacitors in Energy Microharvesting Designs – [Link]
John Donovan writes:
Alternative energy sources deliver small amounts of power intermittently, and at times power levels may not match the needs of the applications that depend on them. Some form of energy storage is needed, though the solution will vary with the demands of the application. This article will examine various energy buffering solutions, including small form-factor batteries, thin-film batteries, and supercapacitors, highlighting both their specifications and the applications to which they are best suited.
Storage Alternatives for Energy Harvesting Applications – [Link]
Double layer electrolytic capacitors already enable to replace backup batteries in many applications.
Modern high-capacity double layer capacitors (also known as supercapacitors) feature a very high energy/volume ratio, compared to usual electrolytic capacitors. Their capacity is so high, that they are able to replace backup batteries in many designs. On the market there are available miniature types as well as physically big types with capacities of tens to hundreds of Farads.
One of the biggest advantages of capacitors in comparison to batteries is their long lifetime, because their electrodes don´t undergo degradation neither after many thousands of cycles. On the other side, even modern batteries have a limited lifetime and a limited number of cycles, because energy storage in batteries is related to chemical changes of electrodes during charge/discharge (change from a solid to a liquid form, crystallization,…), what causes degradation of electrodes.
In our offer, you can find small “coin-type” double layer capacitors suitable for backup power supply of memories. For example a capacitor with a 1F (1000mF=1 000 000 uF) capacity charged at 5V can store energy of 12.5 Jouls (E=1/2*C*U2), what is 12.5 Wattseconds. This energy is in most cases sufficient to ensure a safe backup of memories at a voltage dropout. Such energy is also sufficient for a short time power supply of low power devices. This can be very useful for example for a safe write of data to EEPROM and a safe switch off of a device.
Supercapacitors instead of batteries? – [Link]
The U.S. Department of Energy (DoE)’s Brookhaven National Laboratory recently characterized activated graphene fabricated at the University of Texas-Austin, concluding that it had an energy density that could rival batteries, an energy-release and quick-recharge rate that exceeded batteries, and a lifetime of at least 10,000 charge/discharge cycles.
Used instead of batteries, activated-graphene supercapacitors could last 27 years for a plug-in vehicle recharged once a day. The DoE also speculates that gigantic activated-graphene supercapacitors at power-stations could smooth out power availability from intermittent energy sources, such as wind and solar. [via]
Activated graphene boosts supercaps – [Link]