Modeling, Design, and Fabrication of High-Inductance Bond Wire Microtransformers With Toroidal Ferrite Core

Macrelli, Enrico; Romani, Annalisa; Wang, Ningning; Roy, Saibal; Hayes, Michael; Paganelli, Rudi Paolo; Mathúna, Cian Ó; Tartagni, Marco

doi:10.1109/tpel.2014.2370814

Cited by 32 publications

(25 citation statements)

References 23 publications

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“…In order to resolve this issue, a biasing inductance Lin is added in parallel with C1 in order to let a DC current flow through the FET during the initial stage. [16] The open-loop gain of the oscillator is characterized by the trans-conductance of the transistor, the input impedance of the piezoelectric transformer and its voltage gain. The input & output capacitance are simply the result of having a dielectric between the two metallic plates.…”

Section: Operating Principlementioning

confidence: 99%

Energy Harvesting from a Piezoelectric Transformer

Hallur¹

2018

IJRASET

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Abstract:The piezoelectric transformer is a combination of piezoelectric actuators as the primary side and piezoelectric transducers as the secondary side, both of which work in longitudinal or transverse vibration mode. These actuators and transducers are both made of piezoelectric elements, which are composed of electrode plates and piezoelectric ceramic materials. Instead of the magnetic field coupling between the primary and secondary windings in a conventional magnetic core transformer, piezoelectric transformers transfer electrical energy via electro-mechanical coupling that occurs between the primary and secondary piezoelectric elements for isolation and step-up or step-down voltage conversion. Currently, there are three major types of piezoelectric transformers: Rosen, thickness vibration mode, and radial vibration mode, all three of which are used in DC/DC converters or in electronic ballasts for fluorescent Lamps. Unlike the other 2 transformers, the characterization and modeling of the radial vibration mode piezoelectric transformer have not been studied and developed prior to this work.

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Section: Operating Principlementioning

confidence: 99%

Energy Harvesting from a Piezoelectric Transformer

Hallur¹

2018

IJRASET

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“…, and , as shown in [32] and [37], which comprise eddy-current effects and the complex permeability model, together with an estimate (or measure) of the coupling and of . In Section IV, (16) will be resolved numerically by finding the point at which the oscillation frequency equals the operating frequency of the microtransformer.…”

Section: B Circuit Analysismentioning

confidence: 99%

“…4). The first is the 1:38 turns toroidal MnZn 75 ferrite core reported in [32], with a area and inductance per unit area of 12.8 up to 0.3 MHz. The second is a 1:52 toroidal race-track shaped 40011 ferromagnetic LTCC core similar to that shown in [34], with a area and 1.1 up to several MHz.…”

Section: Properties Of the Bond Wire Microtransformersmentioning

confidence: 99%

“…Nowadays, commercial miniature transformers for EH are available with high inductance and high turns ratio [29], [30], however with: i) high dc resistance, i.e., 200 at secondary for 1:50 turns; ii) large dimensions, i.e., ( ); iii) high profile compared to micro-structures [31]. Besides this, literature reports toroidal microtransformers with bonding wires [32]- [34] with high quality-factor , small area and high turns ratio, which are features of paramount importance for low-voltage step-up oscillators [27]. The use of bonding wires allows in perspective die-level or in-package integration of the whole converter with the magnetics mounted on-top of the IC.…”

Section: Introductionmentioning

confidence: 99%

“…The use of bonding wires allows in perspective die-level or in-package integration of the whole converter with the magnetics mounted on-top of the IC. In [32] and [33], transformers with NiZn and MnZn ferrite cores on a printed circuit board (PCB) substrate are reported with a turns ratio up to 1:38, a self-inductance up to 315…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Design of Low-Voltage Integrated Step-up Oscillators with Microtransformers for Energy Harvesting Applications

Macrelli

Romani

Paganelli

et al. 2015

IEEE Trans. Circuits Syst. I

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This paper describes the modeling of startup circuits in battery-less micropower energy harvesting systems and investigates the use of bond wire micromagnetics. The analysis focuses on step-up Meissner oscillators based on magnetic core transformers operating with input voltages down to 100 mV, e.g., from thermoelectric generators. As a key point, this paper examines the effect of core losses and leakage inductances on the startup requirements obtained with the classical Barkhausen criterion, and demonstrates the minimum transconductance for oscillations to occur. For validation purposes, a step-up oscillator IC is fabricated in a STMicroelectronics 0.32 technology, and connected to two bond wire microtransformers, respectively, with a 1:38 MnZn ferrite core and with a 1:52 ferromagnetic low-temperature co-fired ceramic (LTCC) core. Coherently with the proposed model, experimental measurements show a minimum startup voltage of 228 mV for the MnZn ferrite core and of 104 mV for the LTCC core.

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