Controller Chip Design of A Simple Switched-Coupled-Inductor Boost DC-AC Inverter

This work presents the design and implementation of the controller chip used in a simple switched-coupled-inductor inverter (SCII) for the boost DC-AC conversion/regulation. In the power-conversion part, there are two sub-circuits as: switched-coupled-inductor booster and half-bridge DC-link in a cascade between supply Vs and output Vo, so as to obtain the AC output range: +(1+nD)Vs/(1-D) ~ -nVs (n: turn ratio of coupled inductor, D: ON ratio cycle of inductor-charging). To achieve the boost DC-AC, the control part consists of phase generator and sinusoidal pulse-width-modulation (SPWM) block, and the chip internal circuit is made through pre/post-layout design via Cadence. By the assistance of Chip Design and Implementation Center, this control part is practically fabricated on a real chip (D35-106B-E0027, TSMC 0.35μm 2P4M, 3.3V, 2.146mW, max 100kHz). When n=6, D=0.42, this SCII performs the conversion from DC 24V to AC 100Vrms, 60Hz. Finally, the prototype circuit is implemented, and several cases are illustrated to show the practicality.