A new embedded inductor for ZVS DC-DC converter applications

Abstract

In this paper, a new tapered silicon-embedded coreless power inductor is proposed and demonstrated. The width and depth for the different turns of the inductor are designed with different values to reduce the proximity effect. An 18.6 nH inductance and a peak Q factor of 12.1 are achieved at 23 MHz within a chip area of 0.8 mm 2 . The AC power loss of the inductor is reduced by a maximum of 56% using the novel design. The inductor shows a peak efficiency of 91% in ZVS conversion applications, and is the highest in monolithic ZVS DC-DC converters reported so far.

A low substrate loss, monolithically integrated power inductor for compact LED drivers

“…Therefore, the outer radius of the inductor is selected to be 2.75 mm, which corresponds to an outer diameter of 5.5 mm. The width of the inductor coil (w) is chosen as 30 μm, which is the skin depth of copper at 5 MHz, for suppressing the eddy current loss and proximity effect [8]. The spacing between adjacent turns (s) is designed to be 25 μm for a good mechanical support.…”

“…SU-8 is chosen for embedding the inductor because it is an insulating material with a low permittivity of 3.2 [10], so the capacitive substrate loss can be significantly reduced compared to the inductor which is embedded in a 10 Ω•cm silicon substrate [6,8,11]. HFSS simulation results in Fig.…”