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Brainstorm: Low Power Designs

Mon, 11/28/2011 - 9:24am
Todd Hanson, Director of Strategic Marketing and Wireless Solutions at Honeywell Sensing and Control

Question: What are the primary drivers for developing low power designs? Cost savings, movement to green, longer life for batteries?

ToddHanson










One of the most critical factors for component and board designers pursuing low power wireless designs is the overall power budget. By reducing the power demand of the radio, the designer can allocate more power to other things on the board, adding more features and capabilities, without having to go through a new cycle of development and testing. Low power wireless means it’s easier to live within an existing design with regard to the power budget.

Using a low power radio is critical from the sensor and wireless enabled side that needs to be as ultra-low power as possible. Even if designer has line power to drive the wireless sensor, they still have a power budget to deal with.

For OEMs or circuit developer, the cost savings are not as important as the integrity of the wireless signal. For them, the driver for low power wireless is more about cost and functionality, and for industrial and manufacturing end-users, it is more about reduced maintenance. Battery powered wireless means they no longer have to worry about maintaining cables and connectors that wear out from continual flexing and movement. End users also appreciate the ability to easily and cost efficiently re configure a factory floor without having to run new communication cables and power lines.

There is an interesting green factor. Because of the ability to control and monitor power usage, wireless sensors can provide energy use data that is actionable (fume hoods, current consumption of coolers/freezers in grocery stores, rooftop units). There is a lot of waste in these industrial systems, and by monitoring when these appliances are wasting power, and controlling it, it is possible to greatly slash real world energy use. For example fume hoods are often left open when not in use, allowing hot air to escape during the winter and cool air to escape during the summer.

In addition, by monitoring current usage in motors and compressors, you can tell if the bearings are going bad. Going bad, uses more energy. From a sensor standpoint, developers have been able to do that for years, but it wasn’t feasible from a cost standpoint (too many wires back to a controller). Now with wireless, and the drive to save energy, it’s viable. There’s a value now. 

JohnCarpenter
KarthikKadirvel

by John Carpenter, Karthik Kadirvel, Texas Instruments

Over the past decade, the market has been pushing technology to produce lower power designs – especially for battery-powered products. This push can be attributed to several factors such as the need to increase usable time, reduce operating costs, and enable green-power alternatives. This article delves into these factors and explains how reduction of power consumption contributes to a sustainable planet.

In battery-powered applications, such as mobile phones or music players, the lower power consumed by various integrated circuits (ICs) increases the device’s operational time, which leads to longer time between charge cycles. Generally, batteries have a limited number of charge/discharge cycles. By increasing the usable time per charge/discharge cycle, total battery life is increased, which can significantly reduce the number of batteries being disposed of in landfills. Also, by reducing the frequency of charging, the load on the electrical grid is reduced, thus, reducing our carbon footprint.

In recent years, a considerable effort has been made to design perpetually-powered and battery-free systems that operate from ambient energy. With recent increases in power harvested by various energy transducers combined with the reduced power consumed by electronics, perpetually-powered wireless sensor network (WSN) systems are now feasible. Examples of a few low-power ICs that enable a WSN include power management ICs (bq25504), microprocessors (MSP430), and radios (CC1101). These devices have the potential to revolutionize many industries including environmental monitoring, structural health monitoring, and agricultural monitoring. For instance, self-powered WSNs can be retrofitted to older non-green buildings to monitor room occupancy and to automatically turn off the lights and HVAC systems. This reduces the building’s overall operating costs while also reducing the load on the grid. Another example is to use solar-powered WSNs in an open field to monitor the soil hydration level and turn the irrigation system on and off as needed. This saves water and prevents fertilizer run-off, which leads to a better crop yield with lower costs, and reduces the negative impact of excessive fertilizer runoff into our water drainage system.

In summary, lower power designs enable new applications that can reduce cost, decrease our dependence on fossil fuels, and make the planet a better place to live. 

CeesLinks



by Cees Links, CEO & Founder of GreenPeak - Marketing Chair of the ZigBee RF4CE group

More and more wireless devices around us in our homes are running on batteries: remote controls, thermostats, temperature, smoke and security sensors, etc. As a consequence, we have to often replace or recharge those depleted batteries. This can be quite a nuisance especially when they start beeping in the middle of the night.

As a result of technology improvements, battery life is slowly lengthening. However, the real solution is to make the devices that run of batteries require much less power. By developing smarter and more efficient radio chips in these wireless devices, engineers are working towards the goal of developing wireless devices that can operate for years on a single battery, that can be powered for longer than the estimated life of the product itself. This goal can also be reached with so-called energy harvesters, but these devices are usually too bulky and/or expensive for mass adoption.

At the same time as energy consumption is reduced, additional range and functionality is added. The latest generation low power wireless radio chips can provide a range of up to 150 feet, enough to enabling a remote control to provide an interactive, two way connection, to a central set top box (access point) and then out to the internet. For example, GreenPeak Technologies is developing transceiver chips that can be used in remote controls that support a battery life of more than 10 years at 500 key clicks per day – without compromising range and performance. Accelerating their acceptance, the GreenPeak enabled remote control provides better range than traditional IR-based remote controls along with a better user experience.

Low power wireless is green. Batteries have a heavy carbon footprint, are packed with heavy metals and toxic chemicals, and pose challenges for disposal and recycling. The development of ultra low power radio chips means that despite the exploding growth in the number of wireless devices in our homes, there does not have to be a corresponding demand for more batteries. With the efforts to make designs maintenance free (in other words, only using one battery for the whole life time) this demand for more batteries can be reduced and although not a primary driver for low power wireless – the environment definitely benefits.

Posted by Janine E. Mooney, Editor


November 28, 2011

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