The interior design is instantly recognizable. It is the well-known platform developed and manufactured by Channel Well. It is also used in the 1500W unit from Thermaltake (which will be discussed later in this review) as well as in 1000W and higher power supplies selling under several other brands.
The photo shows clearly the symmetric design of the PSU. You can divide it along the middle into two identical halves. These are actually two power supplies, each for 750W, within a common housing.
The sub-PSUs are only connected by the turn-on circuit because they are started up simultaneously. Each sub-PSU has an active PFC device (the PFC chokes can be seen between the heatsinks in the photo), PWM controller, power transformer, and output rectifiers. In other words, if you take the NRP-HC1501 apart and unsolder about half the components, it will work like a regular 750W power supply.
The single important difference between the sub-PSUs is the selection of voltages they provide. One yields +12V and +5V while the other, +12V and +3.3V. The +5V and +3.3V voltages are generated by dedicated switching regulators mounted on small cards (one such card can be seen in the photo above). These are full-featured power sources with a PWM controller, choke, synchronous rectifier and smoothing capacitors. Each source lowers the input +12V voltage to the necessary level. Thus, the NRP-HC1501 implements dedicated voltage regulation.
The controllers of the main regulators of the sub-PSUs are located on small separate cards and based on Champion Micro CM6800G chips.
And there are two more cards (one for each sub-PSU) with a fan controller and overload & overvoltage protection. Since there is only one fan in the PSU, one card only controls the currents and voltages of its sub-PSU.
In fact, there is nothing extraordinary about the design of each of the sub-PSUs. Excepting the step-down regulators for +5V and +3.3V voltages, they are ordinary modern power supplies with active PFC. And the regulators are used to save space in the first place. The component density is high, and the more widespread design for providing +5V and +3.3V in mainstream and top-end power supplies – by means of saturated-core chokes – just would not fit into the housing. The regulators employed here are more complex and expensive but are implemented as a narrow card that can be easily installed at the side panel of the case.
So, it is the joining of two virtually independent power supplies within one housing that is the unique idea here. But I doubt it will ever be really popular among the manufacturers. This design is complex and expensive and the load must be distributed symmetrically between the sub-PSUs’ outputs in order to get the full output power from the PSU. Moreover, such a high wattage is not actually needed by modern computers.
There is one more card near the external vent grid. It carries the standby source which is shared by both sub-PSUs.
KY series capacitors from United Chemi-Con are installed at the PSU’s output. This company’s products enjoy good reputation, but the KY series has the highest ESR rating among all the series intended for switching power supplies. PSU makers usually prefer the KZE series which has lower ESR.