EVGA's new 700B based on new DC-DC design
Posted on December 12, 2015, 13:52
EVGA launched the 700B model, that you could see in earlier news posts. It doesn't use the group regulated design from the 500B and 600B units, but a new platform with DC-DC modules on the secondary side.
| Series || Model, 80+ ||OEM||The platform||Internal photo||OEM platform reference||Notes|
|B||500B||HEC||"B500"||The 600B uses better APFC FETs and +12V rectifiers.|
|700B||Unnamed||Uses DC-DC converters instead of group regulation scheme|
The DC-DC modules are visible in the top middle part of the picture above. This implementation greatly improves voltage stability in situations with unbalanced loads, where the majority of the power comes from +12V with very little of it being put on the remaining voltages. It also improves efficiency.
Another advantage of power supplies with DC-DC converters is that they can provide the majority of their power on the +12V rail alone, without the need of loading the minor rails with a certain load for it to work. For example, in a good DC-DC PSU you'd be able to get full 700W by only loading the +12V rail, where some older group regulated 700W PSU would only keep voltages in spec if you loaded the +12V rail to 630W and the +5V&3.3V to 70W.
EVGA 700B can provide 672W on the +12V rail, which is an unusually low value compared to other DC-DC units - most of the time their +12V rating doesn't drop further than 0-10 W from the total wattage rating.
As you can see on the photo, the unit uses a Teapo primary capacitor and Teapo electrolytic capacitors on the secondary side. There are two Nippon Chemi-Con capacitors on what is presumably a controller/protection IC board, and two solid capacitors by the DC-DC converters that also seem to be Teapo.
The unit doesn't use an LLC resonant converter and doesn't seem to use any extraordinary topology on the primary side,so it definitely isn't meant to compete with higher-end 80+ Bronze units. Unfortunately it has only two PCI-express 6+2pin connectors, which severely limits its usefulness - 700W is far too much for a single-GPU system, and two connectors are not enough for a Crossfire or SLI configuration.
It currently retails for $75 at Amazon and $65 (discount) at Newegg - we will see if it's a good price once this unit gets properly tested and reviewed.