Low power wake up reciever operating in the
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Transcript of Low power wake up reciever operating in the
Used for Wireless Sensor Networks (WSN).
WSN :- A set of sensor nodes deployed on a
specific location to gather intelligence.
Challenges in WSN are
• Power
• Cost
• Communication protocol
• Size
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Transmitter & Receiver consumes more power.
Ref : Design of an Ultra-Low Power Wake-Up Receiver: Master's Thesis
performed in Electronics systems, Fikre Tsigabu Gebreyohannes, 2012/06/12.
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To reduce power we are using wake up
receivers.
Txr & Rxr are in sleep mode or shut down
entirely.
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WUR is an additional circuitary.
Low power circuit.
Active for extended period of time.
Continuously listen to wireless channel.
When a wake up signal is recieved it activates
other circuits.
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Very low power consumption
Minimise the false wake up signals
Addressing Capability
Flexibility and Usability
• Antenna and Frequency Re-use
• Use Existing Transmitter
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An Envelope detector.
High-gain baseband amplifier
Clock and Data Recovery(CDR) circuit
A wake up signal recognition circuit
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A high-gain baseband amplifier with offset
canceller.
An all-digital, clock and data recovery (CDR)
circuit.
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Ref : Low-power wake-up receiver with subthreshold CMOS circuits for wireless
sensor networks: Kazuhiro Takahagi , Hiromichi Matsushita ,Tomoki Iida Masayuki Ikebe ,Yoshihito Amemiya,Eiichi Sano. IEEE Xplore,15 July 2012
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Ref : Low-power wake-up receiver with subthreshold CMOS circuits for wireless
sensor networks: Kazuhiro Takahagi , Hiromichi Matsushita ,Tomoki Iida Masayuki Ikebe ,Yoshihito Amemiya,Eiichi Sano. IEEE Xplore,15 July 2012
The feedback circuit consists of op amps.
The input-/output- voltages are fixed to Vcm.
The subthreshold op amps operate very slowly.
The differential amplifier operates as a HP filter.
Amp ouput has no DC offsets.
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MOSFETs in the input stage are biased in the
subthreshold region.
Envelope detection was performed with non-
linearity of drain current.
M2 was used as driving MOSFET.
M2 reduces 1/f noise.
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The Id responds instantaneously to variation of
the gate- voltage VGS of the MOSFET M2.
The high gain amplifier with this offset cancellation
circuit has no DC gain.
Amplifies AC input signals.
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Ref : Low-power wake-up receiver with subthreshold CMOS circuits for
wireless sensor networks: Kazuhiro Takahagi , Hiromichi Matsushita ,Tomoki
Iida Masayuki Ikebe ,Yoshihito Amemiya,Eiichi Sano. IEEE Xplore,15 July 2012
Three stage amplification is used.
MOSFET M8 was used as a current mirror circuit.
M8 determines the drain current of the drive
MOSFET (M2) in the detector.
The VCM2 of the 3-stage Amp. was determined
by the ratio of the R3 and R4 resistors.
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External resistors were used for R2–R4 to vary the
current in the gain stages and VCM2.
The circuit performance is affected by variations
in fabrication parameters and ambient
temperature.
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Ref : Low-power wake-up receiver with subthreshold CMOS circuits for wireless
sensor networks: Kazuhiro Takahagi , Hiromichi Matsushita ,Tomoki Iida Masayuki Ikebe ,Yoshihito Amemiya,Eiichi Sano. IEEE Xplore,15 July 2012
When a wake-up signal arrives at the CDR,
the turn- on detection circuit activates the ring OSC
resets the counter
transfers the content of the counter to the register.
The ring oscillator frequency is at least four times
higher than the baseband frequency.
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A 1-bit shifted value of the counted number is
transferred to the register.
When the contents of the counter and the register
coincide with each other, the clock becomes ‘‘high.’’
The clock turns on at the center position of the time
slot.
At this moment, the data is read by using the clock
and a value of ‘‘1’’ or ‘‘0’’ is registered in the D–F/F.
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When the wake-up signal stops and the counter
overflows, the ring oscillator is turned off.
No exact relationship is required between the
oscillation frequency and the baseband frequency.
It is an all-digital circuit.
Average power consumption is almost 0.
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Sensing of wildfires
Drought prediction
Sensing oil leakage
Environmental Monitoring
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Proposed wake up receiver operating in the subthreshold region consumes only less power.
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Low-power wake-up receiver with subthreshold CMOS circuits for wireless
sensor networks: Kazuhiro Takahagi , Hiromichi Matsushita ,Tomoki Iida
Masayuki Ikebe ,Yoshihito Amemiya,Eiichi Sano. IEEE Xplore,15 July
2012.
Design of an Ultra-Low Power Wake-Up Receiver: Master's Thesis
performed in Electronics systems, Fikre Tsigabu Gebreyohannes,
2012/06/12.
Low Power Wake up Receiver for Wireless Sensor Networks: Vikas Kumar
and Rajender Kumar.Electronics & Comm. Engineering Deptt., National
Institute of Technology, Kurukshetra.
www.wikipedia.com.
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THANK YOU
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