At today's International Solid State Circuit Conference, imec
and Holst Centre report a 2.4GHz/915MHz wake-up receiver which consumes only
51µW power. This record low power achievement opens the door to battery-less
or energy-harvesting based radios for a wide range of applications including
long-range RFID and wireless sensor nodes for logistics, smart buildings, healthcare
etc.
Test board of imec and Holst Centre's wake up receiver.
Today’s battery-operated wireless communication systems consume a lot
of power at times when the radio does not have to transmit or receive data.
This means that most of their time Bluetooth or WLAN radios on mobile phones
are taking energy from the battery without adding functionality. Imec and Holst
Centre’s wake-up receiver with ultra-low power consumption and fast response
time can be put in parallel with the conventional radio to switch it on when
data needs to received or transmitted.
Imec and Holst Centre developed an innovative radio architecture based on double
sampling to overcome the 1/f noise problem. This noise affects most low data
rate (10-100kbps) radios. As a consequence, these radios traditionally have
a higher power budget than higher data rate radios achieving the same performance.
By using a double-sampling technique the offset and 1/f noise is reduced and
consequently the sensitivity of the receiver improves proportionally as data-rate
scales.
The wake-up receiver chip was implemented in a 90nm digital CMOS technology
and occupies an area of 0.36mm2. Measurements on silicon show a sensitivity
of -75dBm (SNR>12dB) for the 915MHz receiver at 100kbps OOK (on off keying)
modulation. When scaling the data rate to 10kbps and filtering the out-of-band
noise, the sensitivity is improved by 5dB. For the 2.4GHz receiver, the sensitivity
is -64dBm and -69dBm for 100kbps and 10kbps data rate respectively.
“Within our wireless autonomous sensor system research, we aim to develop
wireless sensor systems powered by energy harvested from the environment instead
of using batteries. The power budget of such systems is only 100µW for
the DSP, radio and sensor. This ultra-low power radio of only 51µW with
small form factor is a major step forward to achieve our goal. It opens the
door to many new battery-less applications such as long-range RFID, smart lighting,
and sensor tags.” said Bert Gyselinckx, general manager imec the Netherlands
at Holst Centre.
Imec performs world-leading research in nano-electronics. Imec leverages its
scientific knowledge with the innovative power of its global partnerships in
ICT, healthcare and energy. Imec delivers industry-relevant technology solutions.
In a unique high-tech environment, its international top talent is committed
to providing the building blocks for a better life in a sustainable society.
Posted February 8th, 2010