PhD student Aidan Rodgers with Advisor A. Stillwell

Data centers require power delivery at a low voltage and a very high current, necessitating high power density and high efficiency point-of-load (PoL) conversion.  As the power demand of data centers increases, processors must include more pins for power delivery.  In-package integration of the point-of-load converter directly with the processor could reduce the current that must be delivered to the processor package, simplifying the power delivery network.  Current-sourced hybrid switched-capacitor converters (SCCs) have recently been proposed for integrated PoL conversion.  This design approach could allow for magnetic components to be connected externally at the input, while the rest of the converter can be more feasibly integrated in-package.  This research proposes a current-sourced hybrid SCC with an input inductor flying capacitor multilevel (FCML) converter as an input stage, shown in Figure 15.  By implementing a multilevel input stage, the input inductors experience a low current ripple, allowing for small input inductors.  A 48 V to 3 V, 100 W prototype with a 4-level input inductor FCML input stage and a 4:1 series-parallel SCC output stage is demonstrated in hardware, shown in Figure 16, using discrete components.  The hardware implementation exhibits a peak efficiency of 93.9% and a power density of 134 W/in3.

High level diagram of proposed current-sourced hybrid SCC.

Hardware prototype of proposed converter.