DARE Page 1 Non-Invasive Induction Link Model for Implantable Biomedical Microsystems: Pacemaker to Monitor Arrhythmic Patients in Body Area Networks Prepared by: Anum Tauqir
Feb 23, 2016
DARE Page 1
Non-Invasive Induction Link Model for Implantable Biomedical Microsystems:
Pacemaker to MonitorArrhythmic Patients in Body Area
Networks
Prepared by:Anum Tauqir
DARE Page 2
Outline Background
Problem Statement
Motivation
Mathematical Model
Equivalent Circuits
Equations
Simulation Results
Conclusion
DARE Page 3
Background
DARE Page 4
Medical Implants aim to: replace missing body parts or
deliver medication, monitor body functions, or provide support to
organs and tissues.
Most widely implanted device: Pacemaker
monitor patients with heart related issues
Most commonly occurring is arrhythmia
DARE Page 5
an abnormal heart rhythm, due to changes in the
conduction of electrical impulses through the heart.
Pacemakers: use low-energy electrical pulses to overcome this abnormality.
They create forced rhythms according to natural human heart
beats, to let the heart to function in a normal manner.
consists of a small battery, a generator and wires attached to the
sensor to be inserted into the patients heart.
Arrhythmia
DARE Page 6
Working of Pacemaker
DARE Page 7
Problem Statement
DARE Page 8
To cater for arrhythmia: generated pulses carry sensed information regarding different
events occurring inside the heart to the doctor
processing and transmission of data,
create a strain on the battery of a pacemaker to consume huge
amount of power that ultimately;
depletes the sensor and hence becomes unable to further carry any
informational data.
DARE Page 9
Motivation
DARE Page 10
Induction technique is presented to: recharge the sensors battery, implanted inside a pacemaker to
avoid early depletion
Technique focuses on enhancing:
voltage gain
link efficiency
Two equivalent circuits: Series tuned primary circuit
Series tuned primary and parallel tuned secondary circuit
DARE Page 11
Mathematical Model
DARE Page 12
Induction Link
Primary Circuit powered by a voltage source
Secondary Circuit Source generates magnetic flux in order to induce power at
secondary side, implanted inside human body. Interface
skin acts as an interface or a barrier between the two circuits.
DARE Page 13
Induction Link Parameters Coupling Co-efficient (k)
degree of coupling between the two circuits.enhances the link efficiency In WBANs for body tissues safety:
k < 0.45
Voltage Gain (Vout / Vin) ratio that, indicates an increase in the voltage at the output side in
relative to the voltage applied at primary side Link Efficiency (η)
ability of transferring power from primary side to secondary side in an efficient manner.
DARE Page 14
Equivalent Circuits
DARE Page 15
Series Tuned Primary Circuit (STPC)
DARE Page 16
a capacitor is connected in series at primary side. as, only a small amount of voltage induces because of a low
coupling factor of 0.45 so, a series tuned circuit is used in order to:
induce sufficient amount of voltage to the secondary coil
DARE Page 17
Series Tuned Primary and Parallel Tuned Secondary Circuit (STPPTSC)
DARE Page 18
capacitor C2p is connected in parallel at secondary side as, the sensors implanted inside a human body operate under low
frequencies. parallel capacitor let the circuit to act as a low pass filter
which, allows low frequencies to pass through and, blocking the higher frequencies thereby,
preventing damages to body tissues
DARE Page 19
Model ParametersParameter Value
Operating frequency f = 13.56 MHz
Primary coil L1 = 5.48 μH
Secondary coil L2 = 1 μH
Parasitic resistance of the transmitter coil
RL1 2.12 ≃ Ω
Parasitic resistance of the receiver coil
RL2 1.63 ≃ Ω
Load resistance Rload = 320 Ω
DARE Page 20
Equations
DARE Page 21
Voltage Gain
For STPC
For STPPTSC
where,
DARE Page 22
Link Efficiency
For STPC
For STPPTSC
where,
where,
DARE Page 23
Simulation Results
DARE Page 24
Voltage Gain of Series Tuned Primary Circuit
DARE Page 25
Link Efficiency of Series Tuned Primary Circuit
DARE Page 26
Voltage Gain of Series Tuned Primary and Parallel Tuned Secondary Circuit
DARE Page 27
Link Efficiency of Series Tuned Primary and Parallel Tuned Secondary Circuit
DARE Page 28
Conclusion
DARE Page 29
DARE Page 30