Radio Chip for the “Internet of things”

Circuit that reduces power leakage when transmitters are idle could greatly extend battery life

At this year’s Consumer Electronics Show in Las Vegas, the big theme was the “Internet of things” — the idea that everything in the human environment, from kitchen appliances to industrial equipment, could be equipped with sensors and processors that can exchange data, helping with maintenance and the coordination of tasks.

Realizing that vision, however, requires transmitters that are powerful enough to broadcast to devices dozens of yards away but energy-efficient enough to last for months — or even to harvest energy from heat or mechanical vibrations.

“A key challenge is designing these circuits with extremely low standby power, because most of these devices are just sitting idling, waiting for some event to trigger a communication,” explains Anantha Chandrakasan, the Joseph F. and Nancy P. Keithley Professor in Electrical Engineering at MIT. “When it’s on, you want to be as efficient as possible, and when it’s off, you want to really cut off the off-state power, the leakage power.”

This week, at the Institute of Electrical and Electronics Engineers’ International Solid-State Circuits Conference, Chandrakasan’s group will present a new transmitter design that reduces off-state leakage 100-fold. At the same time, it provides adequate power for Bluetooth transmission, or for the even longer-range 802.15.4 wireless-communication protocol.

“The trick is that we borrow techniques that we use to reduce the leakage power in digital circuits,” Chandrakasan explains. The basic element of a digital circuit is a transistor, in which two electrical leads are connected by a semiconducting material, such as silicon. In their native states, semiconductors are not particularly good conductors. But in a transistor, the semiconductor has a second wire sitting on top of it, which runs perpendicularly to the electrical leads. Sending a positive charge through this wire — known as the gate — draws electrons toward it. The concentration of electrons creates a bridge that current can cross between the leads.

But while semiconductors are not naturally very good conductors, neither are they perfect insulators. Even when no charge is applied to the gate, some current still leaks across the transistor. It’s not much, but over time, it can make a big difference in the battery life of a device that spends most of its time sitting idle.

Going negative

Chandrakasan — along with Arun Paidimarri, an MIT graduate student in electrical engineering and computer science and first author on the paper, and Nathan Ickes, a research scientist in Chandrakasan’s lab — reduces the leakage by applying a negative charge to the gate when the transmitter is idle. That drives electrons away from the electrical leads, making the semiconductor a much better insulator.

Of course, that strategy works only if generating the negative charge consumes less energy than the circuit would otherwise lose to leakage. In tests conducted on a prototype chip fabricated through the Taiwan Semiconductor Manufacturing Company’s research program, the MIT researchers found that their circuit spent only 20 picowatts of power to save 10,000 picowatts in leakage.

To generate the negative charge efficiently, the MIT researchers use a circuit known as a charge pump, which is a small network of capacitors — electronic components that can store charge — and switches. When the charge pump is exposed to the voltage that drives the chip, charge builds up in one of the capacitors. Throwing one of the switches connects the positive end of the capacitor to the ground, causing a current to flow out the other end. This process is repeated over and over. The only real power drain comes from throwing the switch, which happens about 15 times a second.

Turned on

To make the transmitter more efficient when it’s active, the researchers adopted techniques that have long been a feature of work in Chandrakasan’s group. Ordinarily, the frequency at which a transmitter can broadcast is a function of its voltage. But the MIT researchers decomposed the problem of generating an electromagnetic signal into discrete steps, only some of which require higher voltages. For those steps, the circuit uses capacitors and inductors to increase voltage locally. That keeps the overall voltage of the circuit down, while still enabling high-frequency transmissions.

What those efficiencies mean for battery life depends on how frequently the transmitter is operational. But if it can get away with broadcasting only every hour or so, the researchers’ circuit can reduce power consumption 100-fold.

This research was funded by Shell and Texas Instruments.

###

Written by Larry Hardesty, MIT News Office

Related links

Wireless Charging Technology: Receiver and Transmitter ICs Worldwide Forecasts

Radio Chip for the “Internet of things”

Radio Chip for the “Internet of things”

Circuit that reduces power leakage when transmitters are idle could greatly extend battery life

At this year’s Consumer Electronics Show in Las Vegas, the big theme was the “Internet of things” — the idea that everything in the human environment, from kitchen appliances to industrial equipment, could be equipped with sensors and processors that can exchange data, helping with maintenance and the coordination of tasks.

Realizing that vision, however, requires transmitters that are powerful enough to broadcast to devices dozens of yards away but energy-efficient enough to last for months — or even to harvest energy from heat or mechanical vibrations.

“A key challenge is designing these circuits with extremely low standby power, because most of these devices are just sitting idling, waiting for some event to trigger a communication,” explains Anantha Chandrakasan, the Joseph F. and Nancy P. Keithley Professor in Electrical Engineering at MIT. “When it’s on, you want to be as efficient as possible, and when it’s off, you want to really cut off the off-state power, the leakage power.”

This week, at the Institute of Electrical and Electronics Engineers’ International Solid-State Circuits Conference, Chandrakasan’s group will present a new transmitter design that reduces off-state leakage 100-fold. At the same time, it provides adequate power for Bluetooth transmission, or for the even longer-range 802.15.4 wireless-communication protocol.

“The trick is that we borrow techniques that we use to reduce the leakage power in digital circuits,” Chandrakasan explains. The basic element of a digital circuit is a transistor, in which two electrical leads are connected by a semiconducting material, such as silicon. In their native states, semiconductors are not particularly good conductors. But in a transistor, the semiconductor has a second wire sitting on top of it, which runs perpendicularly to the electrical leads. Sending a positive charge through this wire — known as the gate — draws electrons toward it. The concentration of electrons creates a bridge that current can cross between the leads.

But while semiconductors are not naturally very good conductors, neither are they perfect insulators. Even when no charge is applied to the gate, some current still leaks across the transistor. It’s not much, but over time, it can make a big difference in the battery life of a device that spends most of its time sitting idle.

Going negative

Chandrakasan — along with Arun Paidimarri, an MIT graduate student in electrical engineering and computer science and first author on the paper, and Nathan Ickes, a research scientist in Chandrakasan’s lab — reduces the leakage by applying a negative charge to the gate when the transmitter is idle. That drives electrons away from the electrical leads, making the semiconductor a much better insulator.

Of course, that strategy works only if generating the negative charge consumes less energy than the circuit would otherwise lose to leakage. In tests conducted on a prototype chip fabricated through the Taiwan Semiconductor Manufacturing Company’s research program, the MIT researchers found that their circuit spent only 20 picowatts of power to save 10,000 picowatts in leakage.

To generate the negative charge efficiently, the MIT researchers use a circuit known as a charge pump, which is a small network of capacitors — electronic components that can store charge — and switches. When the charge pump is exposed to the voltage that drives the chip, charge builds up in one of the capacitors. Throwing one of the switches connects the positive end of the capacitor to the ground, causing a current to flow out the other end. This process is repeated over and over. The only real power drain comes from throwing the switch, which happens about 15 times a second.

Turned on

To make the transmitter more efficient when it’s active, the researchers adopted techniques that have long been a feature of work in Chandrakasan’s group. Ordinarily, the frequency at which a transmitter can broadcast is a function of its voltage. But the MIT researchers decomposed the problem of generating an electromagnetic signal into discrete steps, only some of which require higher voltages. For those steps, the circuit uses capacitors and inductors to increase voltage locally. That keeps the overall voltage of the circuit down, while still enabling high-frequency transmissions.

What those efficiencies mean for battery life depends on how frequently the transmitter is operational. But if it can get away with broadcasting only every hour or so, the researchers’ circuit can reduce power consumption 100-fold.

This research was funded by Shell and Texas Instruments.

###

Written by Larry Hardesty, MIT News Office

Related links

Wireless Charging Technology: Receiver and Transmitter ICs Worldwide Forecasts

Radio Chip for the “Internet of things”

Radio Chip for the “Internet of things”

Circuit that reduces power leakage when transmitters are idle could greatly extend battery life

At this year’s Consumer Electronics Show in Las Vegas, the big theme was the “Internet of things” — the idea that everything in the human environment, from kitchen appliances to industrial equipment, could be equipped with sensors and processors that can exchange data, helping with maintenance and the coordination of tasks.

Realizing that vision, however, requires transmitters that are powerful enough to broadcast to devices dozens of yards away but energy-efficient enough to last for months — or even to harvest energy from heat or mechanical vibrations.

“A key challenge is designing these circuits with extremely low standby power, because most of these devices are just sitting idling, waiting for some event to trigger a communication,” explains Anantha Chandrakasan, the Joseph F. and Nancy P. Keithley Professor in Electrical Engineering at MIT. “When it’s on, you want to be as efficient as possible, and when it’s off, you want to really cut off the off-state power, the leakage power.”

This week, at the Institute of Electrical and Electronics Engineers’ International Solid-State Circuits Conference, Chandrakasan’s group will present a new transmitter design that reduces off-state leakage 100-fold. At the same time, it provides adequate power for Bluetooth transmission, or for the even longer-range 802.15.4 wireless-communication protocol.

“The trick is that we borrow techniques that we use to reduce the leakage power in digital circuits,” Chandrakasan explains. The basic element of a digital circuit is a transistor, in which two electrical leads are connected by a semiconducting material, such as silicon. In their native states, semiconductors are not particularly good conductors. But in a transistor, the semiconductor has a second wire sitting on top of it, which runs perpendicularly to the electrical leads. Sending a positive charge through this wire — known as the gate — draws electrons toward it. The concentration of electrons creates a bridge that current can cross between the leads.

But while semiconductors are not naturally very good conductors, neither are they perfect insulators. Even when no charge is applied to the gate, some current still leaks across the transistor. It’s not much, but over time, it can make a big difference in the battery life of a device that spends most of its time sitting idle.

Going negative

Chandrakasan — along with Arun Paidimarri, an MIT graduate student in electrical engineering and computer science and first author on the paper, and Nathan Ickes, a research scientist in Chandrakasan’s lab — reduces the leakage by applying a negative charge to the gate when the transmitter is idle. That drives electrons away from the electrical leads, making the semiconductor a much better insulator.

Of course, that strategy works only if generating the negative charge consumes less energy than the circuit would otherwise lose to leakage. In tests conducted on a prototype chip fabricated through the Taiwan Semiconductor Manufacturing Company’s research program, the MIT researchers found that their circuit spent only 20 picowatts of power to save 10,000 picowatts in leakage.

To generate the negative charge efficiently, the MIT researchers use a circuit known as a charge pump, which is a small network of capacitors — electronic components that can store charge — and switches. When the charge pump is exposed to the voltage that drives the chip, charge builds up in one of the capacitors. Throwing one of the switches connects the positive end of the capacitor to the ground, causing a current to flow out the other end. This process is repeated over and over. The only real power drain comes from throwing the switch, which happens about 15 times a second.

Turned on

To make the transmitter more efficient when it’s active, the researchers adopted techniques that have long been a feature of work in Chandrakasan’s group. Ordinarily, the frequency at which a transmitter can broadcast is a function of its voltage. But the MIT researchers decomposed the problem of generating an electromagnetic signal into discrete steps, only some of which require higher voltages. For those steps, the circuit uses capacitors and inductors to increase voltage locally. That keeps the overall voltage of the circuit down, while still enabling high-frequency transmissions.

What those efficiencies mean for battery life depends on how frequently the transmitter is operational. But if it can get away with broadcasting only every hour or so, the researchers’ circuit can reduce power consumption 100-fold.

This research was funded by Shell and Texas Instruments.

###

Written by Larry Hardesty, MIT News Office

Related links

Wireless Charging Technology: Receiver and Transmitter ICs Worldwide Forecasts

Radio Chip for the “Internet of things”

Wireless Charging ICs Market Report

The First Edition analysis of the Wireless Charging Market is an in-depth analysis detailing the latest developments in this important emerging market. The wireless power charging IC market will see tremendous growth over the next five years, with a dollar market increasing from $284.3 million in 2015 to over $2.8 billion in 2020, a compounded annual growth rate (CAGR) of 58.7%. The wireless power charging market covered in this report is made up of both wireless charging receiver ICs and transmitter ICs. But the longer-term market growth is still uncertain.

“While wireless charging is rapidly gaining market share, its continued success and the final size of the wireless charging market is still to be determined,” stated Richard Ruiz, analyst and author of this report. “There are a number of significant factors that could derail this emerging market including the continued uncertainty of the standards environment, especially the on-going development of a new standard by IEEE and the uncertainty regarding the efficacy of wireless charging relative to energy efficiency standards such as the California Energy Commission (CEC), Level V, that mandates ac adapters meet a minimum efficiency of 85%. It remains to be seen if wireless charging technology can meet this requirement. For these and other reasons, wireless charging is not a ‘done deal’,” Ruiz concluded. The elimination of the need to maintain multiple external power supplies, one for each electronic device, has long been a goal for both the consumers and manufacturers of consumer electronics equipment and over the past several years there have been a number of developments moving the industry towards this goal. In the medium- and longer-terms, the differing growth rates for transmitters and receivers will have a significant impact on the opportunities for companies offering wireless charging. For example, in 2015, the receiver units market is over three times as large and by 2020 it is almost five times larger. This spread will continue to grow as both markets approach different saturation levels and different long-term growth rates.

Additional forecasts in this report include both low and medium power receiver and transmitter ICs for both Wireless Power Consortium Qi technology and A4WP technology. Driven by the large mobile phone market, over the forecast period the receiver IC market is projected to be dominated by Qi technology, while the transmitter IC market will have a higher percentage of A4WP technology. For the purpose of this report, the A4WP and PMA products have been combined.

Among the additional areas to watch are advances in IC technology, in particular advanced semiconductor developments which are moving towards circuits with dual-mode wireless power capability, components and materials, and advances in digital power technology. Also important to observe are a number of long-term alliances and partnerships as well as developments in standards and regulations, efficiency and standby power requirements and the clear long-term shift from first generation (tightly-coupled) to second-generation (flexibly-coupled) wireless power transfer technologies.

Wireless Charging ICs Market Report

This 106-page report contains over 45 tables, graphs and illustrations covering the wireless charging market, including a market share for key suppliers. The focus of this comprehensive analysis is to provide decision makers and manufacturers and operations with a detailed and insightful look at the current and future opportunities available in the wireless charger IC market. Details of the new report, table of contents and ordering information can be found on Electronics.ca Publications’ web site.

View the report: “Wireless Charging Technology: Receiver and Transmitter ICs Worldwide Forecasts“.

 

Wireless Charging ICs Market Report

Wireless Charging ICs Market Report

The First Edition analysis of the Wireless Charging Market is an in-depth analysis detailing the latest developments in this important emerging market. The wireless power charging IC market will see tremendous growth over the next five years, with a dollar market increasing from $284.3 million in 2015 to over $2.8 billion in 2020, a compounded annual growth rate (CAGR) of 58.7%. The wireless power charging market covered in this report is made up of both wireless charging receiver ICs and transmitter ICs. But the longer-term market growth is still uncertain.

“While wireless charging is rapidly gaining market share, its continued success and the final size of the wireless charging market is still to be determined,” stated Richard Ruiz, analyst and author of this report. “There are a number of significant factors that could derail this emerging market including the continued uncertainty of the standards environment, especially the on-going development of a new standard by IEEE and the uncertainty regarding the efficacy of wireless charging relative to energy efficiency standards such as the California Energy Commission (CEC), Level V, that mandates ac adapters meet a minimum efficiency of 85%. It remains to be seen if wireless charging technology can meet this requirement. For these and other reasons, wireless charging is not a ‘done deal’,” Ruiz concluded. The elimination of the need to maintain multiple external power supplies, one for each electronic device, has long been a goal for both the consumers and manufacturers of consumer electronics equipment and over the past several years there have been a number of developments moving the industry towards this goal. In the medium- and longer-terms, the differing growth rates for transmitters and receivers will have a significant impact on the opportunities for companies offering wireless charging. For example, in 2015, the receiver units market is over three times as large and by 2020 it is almost five times larger. This spread will continue to grow as both markets approach different saturation levels and different long-term growth rates.

Additional forecasts in this report include both low and medium power receiver and transmitter ICs for both Wireless Power Consortium Qi technology and A4WP technology. Driven by the large mobile phone market, over the forecast period the receiver IC market is projected to be dominated by Qi technology, while the transmitter IC market will have a higher percentage of A4WP technology. For the purpose of this report, the A4WP and PMA products have been combined.

Among the additional areas to watch are advances in IC technology, in particular advanced semiconductor developments which are moving towards circuits with dual-mode wireless power capability, components and materials, and advances in digital power technology. Also important to observe are a number of long-term alliances and partnerships as well as developments in standards and regulations, efficiency and standby power requirements and the clear long-term shift from first generation (tightly-coupled) to second-generation (flexibly-coupled) wireless power transfer technologies.

Wireless Charging ICs Market Report

This 106-page report contains over 45 tables, graphs and illustrations covering the wireless charging market, including a market share for key suppliers. The focus of this comprehensive analysis is to provide decision makers and manufacturers and operations with a detailed and insightful look at the current and future opportunities available in the wireless charger IC market. Details of the new report, table of contents and ordering information can be found on Electronics.ca Publications’ web site.

View the report: “Wireless Charging Technology: Receiver and Transmitter ICs Worldwide Forecasts“.

 

Wireless Charging ICs Market Report

Radio Chip for the “Internet of things”

Circuit that reduces power leakage when transmitters are idle could greatly extend battery life

At this year’s Consumer Electronics Show in Las Vegas, the big theme was the “Internet of things” — the idea that everything in the human environment, from kitchen appliances to industrial equipment, could be equipped with sensors and processors that can exchange data, helping with maintenance and the coordination of tasks.

Realizing that vision, however, requires transmitters that are powerful enough to broadcast to devices dozens of yards away but energy-efficient enough to last for months — or even to harvest energy from heat or mechanical vibrations.

“A key challenge is designing these circuits with extremely low standby power, because most of these devices are just sitting idling, waiting for some event to trigger a communication,” explains Anantha Chandrakasan, the Joseph F. and Nancy P. Keithley Professor in Electrical Engineering at MIT. “When it’s on, you want to be as efficient as possible, and when it’s off, you want to really cut off the off-state power, the leakage power.”

This week, at the Institute of Electrical and Electronics Engineers’ International Solid-State Circuits Conference, Chandrakasan’s group will present a new transmitter design that reduces off-state leakage 100-fold. At the same time, it provides adequate power for Bluetooth transmission, or for the even longer-range 802.15.4 wireless-communication protocol.

“The trick is that we borrow techniques that we use to reduce the leakage power in digital circuits,” Chandrakasan explains. The basic element of a digital circuit is a transistor, in which two electrical leads are connected by a semiconducting material, such as silicon. In their native states, semiconductors are not particularly good conductors. But in a transistor, the semiconductor has a second wire sitting on top of it, which runs perpendicularly to the electrical leads. Sending a positive charge through this wire — known as the gate — draws electrons toward it. The concentration of electrons creates a bridge that current can cross between the leads.

But while semiconductors are not naturally very good conductors, neither are they perfect insulators. Even when no charge is applied to the gate, some current still leaks across the transistor. It’s not much, but over time, it can make a big difference in the battery life of a device that spends most of its time sitting idle.

Going negative

Chandrakasan — along with Arun Paidimarri, an MIT graduate student in electrical engineering and computer science and first author on the paper, and Nathan Ickes, a research scientist in Chandrakasan’s lab — reduces the leakage by applying a negative charge to the gate when the transmitter is idle. That drives electrons away from the electrical leads, making the semiconductor a much better insulator.

Of course, that strategy works only if generating the negative charge consumes less energy than the circuit would otherwise lose to leakage. In tests conducted on a prototype chip fabricated through the Taiwan Semiconductor Manufacturing Company’s research program, the MIT researchers found that their circuit spent only 20 picowatts of power to save 10,000 picowatts in leakage.

To generate the negative charge efficiently, the MIT researchers use a circuit known as a charge pump, which is a small network of capacitors — electronic components that can store charge — and switches. When the charge pump is exposed to the voltage that drives the chip, charge builds up in one of the capacitors. Throwing one of the switches connects the positive end of the capacitor to the ground, causing a current to flow out the other end. This process is repeated over and over. The only real power drain comes from throwing the switch, which happens about 15 times a second.

Turned on

To make the transmitter more efficient when it’s active, the researchers adopted techniques that have long been a feature of work in Chandrakasan’s group. Ordinarily, the frequency at which a transmitter can broadcast is a function of its voltage. But the MIT researchers decomposed the problem of generating an electromagnetic signal into discrete steps, only some of which require higher voltages. For those steps, the circuit uses capacitors and inductors to increase voltage locally. That keeps the overall voltage of the circuit down, while still enabling high-frequency transmissions.

What those efficiencies mean for battery life depends on how frequently the transmitter is operational. But if it can get away with broadcasting only every hour or so, the researchers’ circuit can reduce power consumption 100-fold.

This research was funded by Shell and Texas Instruments.

###

Written by Larry Hardesty, MIT News Office

Related links

Wireless Charging Technology: Receiver and Transmitter ICs Worldwide Forecasts

Radio Chip for the “Internet of things”