Design and fabrication of a 29 H bondwire micro-transformer with LTCC magnetic core on silicon for energy harvesting applications

This paper presents the design of a 1 : 50 bondwire micro-transformer assembled with IC gold bonding wires and a toroidal LTCC magnetic core with race-track shape. The transformer is fabricated on-top of a standard BCD IC in a 15 mm footprint area for micro-power energy harvesting applications. Measurements show a secondary self-inductance up to 29 μH with a maximum Q-factor of 11.6 at 1.3 MHz, and a coupling coefficient of 0.65 with an effective turns ratio of 19. This miniaturized technology finds also applications in power supply in package (PwrSiP) and power supply on chip (PwrSoC).