DAREPage 1 Non-Invasive Induction Link Model for Implantable Biomedical Microsystems: Pacemaker to Monitor Arrhythmic Patients in Body Area Networks Prepared by: Anum Tauqir

DAREPage 2 Outline  Background  Problem Statement  Motivation  Mathematical Model  Equivalent Circuits  Equations  Simulation Results  Conclusion

DAREPage 3 Background

DAREPage 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

DAREPage 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

DAREPage 6 Working of Pacemaker

DAREPage 7 Problem Statement

DAREPage 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.

DAREPage 9 Motivation

DAREPage 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

DAREPage 11 Mathematical Model

DAREPage 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.

DAREPage 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 (V out / V in )  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.

DAREPage 14 Equivalent Circuits

DAREPage 15 Series Tuned Primary Circuit (STPC)

DAREPage 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

DAREPage 17 Series Tuned Primary and Parallel Tuned Secondary Circuit (STPPTSC)

DAREPage 18  capacitor C 2p 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

DAREPage 19 Model Parameters ParameterValue Operating frequencyf = MHz Primary coilL 1 = 5.48 μH Secondary coilL 2 = 1 μH Parasitic resistance of the transmitter coil R L1 ≃ 2.12 Ω Parasitic resistance of the receiver coil R L2 ≃ 1.63 Ω Load resistanceR load = 320 Ω

DAREPage 20 Equations

DAREPage 21 Voltage Gain For STPC For STPPTSC where,

DAREPage 22 Link Efficiency For STPC For STPPTSC where,

DAREPage 23 Simulation Results

DAREPage 24 Voltage Gain of Series Tuned Primary Circuit

DAREPage 25 Link Efficiency of Series Tuned Primary Circuit

DAREPage 26 Voltage Gain of Series Tuned Primary and Parallel Tuned Secondary Circuit

DAREPage 27 Link Efficiency of Series Tuned Primary and Parallel Tuned Secondary Circuit

DAREPage 28 Conclusion

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