A 12V-to-PoL CCC-Based Easy-Scalable Multiple-Phase Hybrid Converter with Auto VCF Balancing and Inactive CF Charging

In datacenter, a single-stage conversion from 12-V VIN to point-of-load PoL is favorable. Hybrid converters with 2:1 pre-stage switch-capacitor (SC), such as Double-Step-Down (DSD) [1] and flying capacitor <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CF</tex> -Cross-Connected (CCC) [2], have higher power density and efficiency than the conventional buck. Additionally, these hybrid converters fits the 12V-to-PoL applications better than those works with more complex SC networks. Meanwhile, to conduct a large load current <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ILOAD</tex> , a multiple-phase MP converter may be mandatory. <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">In</tex> this work, we propose CCC-based MP hybrid converter, evolving from the 2-phase (2P) CCC as shown in Fig. 1. The <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2P</tex> CCC has two CFS (CFA, CFB), two inductors <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LA, LB</tex> , two <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">VIN</tex> -stress switches <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MA 2, MB 2</tex> , four <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">VIN / 2</tex> -stress switches <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MA 1, MA 4, MB 1, MB 4</tex> . We split the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">VIN</tex> -stress switches into two <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">VIN/2</tex> -stress, e.g. <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MA2</tex> becomes <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MA2</tex> ' and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MA3()</tex> . The nodes between the split switches VOCA, VOCB are DC nodes <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">=VIN/2</tex> . Then, we connect the DC nodes as VDc, and now the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2P</tex> converter has two symmetric sub-converters. Fig. 1 shows that with the same total power switch area, the simulated power conversion efficiency PCE is almost the same before and after the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M₂</tex> split. This decouples the two phases of the original CCC, and we can extend the number of phases <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</tex> ., Meanwhile, it inherits most CCC's benefits, such as higher efficiency and power density than the MP buck, and fast transient response than DSD [2]. Its sub-converter shares a similar topology to [3], but removes DC capacitor.