The bq25504 from Texas Instruments is a good candidate to become a milestone on the road to micro-power management and energy harvesting. A prominent feature of this IC is its ability to start up at a supply voltage as low as 330 mV typically, and 450 mV guaranteed. With an SMD inductor and a few capacitors and resistors, it forms a dc-dc converter with a high power efficiency that is unprecedented, especially in the ultralow-power region.
DC-DC converter starts up and operates from a single photocell – [Link]
There is energy everywhere around us and in many different forms. Many devices have been developed to harvest light, wind, waves, and more. One unusual place of energy harvesting is from passing cars. As cars pass by some of their energy is released in form of sound. Even though the overall energy maybe small it can be harvested. In this Instructable I will show how to apply the solution of Euler–Bernoulli beam theory to design a cantilever beam to oscillate at such a frequency to adsorb sound waves as well as converting its mechanical motion into electricity.
Harvesting Sound Energy From Passing Cars – [Link]
Renesas Electronics Corporation announced the successful development of a new low-power SRAM circuit technology that achieves a record ultra-low power consumption of 13.7 nW/Mbit in standby mode. The prototype SRAM also achieves a high-speed readout time of 1.8 ns during active operation. RenesasElectronics applied its 65nm node silicon on thin buried oxide (SOTB) process to develop this record-creating SRAM prototype.
This new low-power SRAM circuit technology can be embedded in application specific standard products (ASSPs) for Internet of Things (IoT), home electronics, and healthcare applications. The fast growth of IoT is requiring all the devices be connected to a wireless network all the time. Hence, products must consume less power to prolong battery life. With this new technology applied, much longer battery life can be achieved enabling maintenance-free applications.
One essential part of the development of IoT applications is the miniaturization of end products. This can be achieved by lowering battery capacity requirement of ASSPs. As an effort to reduce the power consumption in ASSPs for the IoT, there is a technique in which the application is operated in the standby mode and only goes to the active mode when data processing is required.
Now, the conventional way of saving power is to store all important data to an internal/external non-volatile memory and cut off the power supply to the circuit. If the wait time is long enough, this method is effective. But in most of the cases, the device has to switch between standby mode and active mode very quickly causing data-saving and restarting process extremely inefficient. There are even cases where, inversely, this increases power consumption.
In contrary to above, the new technology by Renesas Electronics uses a method where power consumption in standby mode is reduced a lot enabling switching operation to be performed frequently without leading to increased power consumption. Hence, it’s no more required to save data to non-volatile memory. This improves the efficiency further.
The low-power embedded SRAM which is fabricated using the 65 nm SOTB process, achieves both the low standby mode power consumption and increased operating speed. Such features were difficult to achieve with the continuing progress of the semiconductor process miniaturization. Renesas plans to support both energy harvesting operation and development of maintenance free IoT applications that do not require battery replacement by enabling ASSPs that adopt the embedded SRAM with SOTB structure.
To learn about all the complex technical information which is not covered in the scope of this article, visit the press release page of Renesas Electronics.
Vamsi Talla at the University of Washington in Seattle build a mobile phone that can rely only on energy that it could harvest from its surroundings. Imagine if you can send SMS or make a call when you are out of battery. That’s what’s the team trying to achieve.
Ambient light can be turned into a trickle of electricity with solar panels or photodiodes. Radio-frequency TV and Wi-Fi broadcasts can be converted into energy using an antenna. A hybrid system using both technologies might generate a few tens of microwatts.
Cell Phone Can Make Calls Without a Battery – [Link]
Cypress Semiconductor has introduced what it believes to be the lowest-available-power PMICs that enable an integrated module size of 1 cm² for solar-powered wireless sensor node (WSN) designs.
Intended to manage solar-powered wireless sensors for Internet of Things (IoT) applications, these parts are said to be the lowest-power, single-chip Energy Harvesting PMICs, and can be used with solar cells as small as 1 cm². Cypress offers a complete, battery-free energy harvesting solution that pairs the S6AE101A PMIC, the first device in the new family, with the EZ-BLE PRoC module for Bluetooth Low Energy connectivity, along with supporting software, in a $49 kit.
Energy-harvesting power management ICs for wireless sensor nodes – [Link]
Recently, I built an energy harvesting circuit based on an ultra low voltage DC/DC step up converter chip (LTC3108) from Linear Technology. With a 1:100 coil transformer (CoilCraft LPR6235), it converts the tiny voltage generated from Peltier thermo-electric generator into high enough level to drive small circuits.