A novel phase-shifting circuit using digital first-in-first-out (FIFO) for multiphase power converter interleaved control

Multiphase interleaving technology allows significant reduction on current ripple and filter size, and thus is well received in power electronics industry. Conventional interleaved control signals are generated by multiple RC timing circuits, which are synchronized externally to obtain phase shift between two adjacent phases. Because of the variation of RC component values, the unbalance between phases is unavoidable. In this paper, the use of digital FIFO circuit as a phase-shifter is proposed. It inherently benefits from the advantage of digital circuit accuracy and stability, and saves a lot of efforts on synchronizing multiple timing signal sources. The principle of such phase-shifter is explained, and the method of applying FIFO phase-shifter for converter interleaved control is depicted. A design example is shown for a 3-phase 6-leg converter control. The hardware test and experimental results verify the effectiveness of such digital FIFO circuit in the power converter controller design.