Providing the multiple supply rails required by SoCs, FPGAs, and ASICs always presents a design challenge with respect to power efficiency, PCB real estate, thermal management, and cost. Intel has just introduced an intriguing new step-down regulator, called the Intel® Enpirion® EC2650QI 6A bus converter, which might well find its way into your power supply toolbox. You can use this switching buck regulator/bus converter to convert a 12V main power bus into a 6V (5.5V at 6A) power bus, so that secondary regulators can then generate the final set of required supply voltages as illustrated in Figure 1. (Note: The secondary regulators attached to the 6V power rail shown in Figure 1 generate power supply rails with output currents on the order of 1A to 6A. For high-current supplies, it makes more sense to use the 12V supply directly, as shown at the top of Figure 1.)
Figure 1: The Intel Enpirion EC2650QI bus converter can create a 6V intermediate power supply bus, which deliver several design benefits including a small PCB real estate, lower power subsystem cost, and easier heat distribution.
Although it may seem counterintuitive, creating a secondary 6V supply bus to power a group of secondary POL regulators brings several significant design benefits including a reduction in the size of PCB real estate, the ability to use lower-cost final regulators, and easier thermal management.
Spacecraft power systems have long used intermediate power rails and modular point-of-load (POL) regulators to improve overall system performance and reliability and to help distribute and manage heat loads. The introduction of the Intel Enpirion EC2650QI bus converter now makes it possible to realize the benefits of such power-distribution systems while reducing overall costs.
First, the Intel Enpirion EC2650QI bus converter is quite small, measuring 5.5 by 5.5 by 0.9 mm. In addition, these converters employ a switched-capacitor topology with low-ESR ceramic filter capacitors on the inputs and outputs, as shown in Figure 2. They do not require bulky inductors and the lack of inductors reduces both board real estate and BOM cost. In fact, the Intel Enpirion EC2650QI bus converter is so thin (0.9mm) that it is often possible to put the entire intermediate bus-converter design on the back of a board, which can save even more PCB area.
Figure 2: Intel Enpirion EC2650QI bus converters use low-ESR ceramic capacitors instead of inductors for power conversion, which results in a small board footprint and lower BOM costs.
Second, using the Intel Enpirion EC2650QI bus converter to generate a secondary 6V power bus allows you to better distribute the heat in your system by moving roughly half of the heat dissipation from the power subsystem away from the POL regulators, when compared to 12V systems. The ability to more evenly distribute heat sources in a system can simplify and reduce the number of components needed for system cooling (heat sinks, heat pipes, fans, etc.).
Third, generating a lower bus voltage to power the secondary regulators actually can reduce the cost of the secondary regulators, because they can be fabricated in a lower-cost, lower-voltage IC process technology. These secondary POL regulators will therefore be less expensive because they can count on a low, constant input voltage for their input power.
Generating a secondary power bus in this manner only makes design sense if the bus converter is extremely efficient. At its nominal 100 KHz switching frequency, the Intel Enpirion EC2650QI converter is 94% efficient.
Another cost-reducing feature is the ability to wire as many as four Intel Enpirion EC2650QI bus converters in parallel using a master/slave configuration to increase the available power on the secondary 6V power bus. Each Intel Enpirion EC2650QI bus converter can source 33 watts of power, so four of these regulators wired in parallel can source 132 watts. Wiring two or more Enpirion EC2650QI bus converters in parallel and synchronizing them is a simple matter, as summarized in Figure 3.
Figure 3: Two to four Intel Enpirion EC2650QI regulators can be wired in parallel to boost secondary bus capacity to 144 watts.
Intel offers a wide range of high-efficiency PowerSoC switching regulators that can be powered from a secondary 6V supply bus generated by one or more Enpirion EC2650QI bus converters. Further, Intel has developed a number of drop-in boards based on these power devices, as shown in Figure 4 and 5 below, to make it easy for you to evaluate the Intel Enpirion EC2650QI bus converter and the range of compatible Intel Enpirion regulators for your system’s power requirements.
Figure 4: Drop-in board for the Intel Enpirion EC2650QI bus converter.
Figure 5: Drop-in boards for the Intel Enpirion EN6363QI and EN6382QI PowerSoC regulators.
Click here for the Intel Enpirion EC2650QI bus converter data sheet.
For more information on Intel Enpirion PowerSoC voltage regulators, click here.