This PSU has an ordinary appearance, differing from Seasonic’ previous products with the shape of the heatsinks only. Two of them have acquired very wide petals while the third, with the power elements of the active PFC device, has become smaller and is inconspicuous among other components.
The PSU has one power transformer. Its active PFC and main regulator are based on the Champion Micro CM6802 controller (a 338KB PDF).
The most interesting thing is hidden beneath the cables: it is a narrow aluminum bar standing near the big heatsink. This bar is a dedicated heatsink of a DC-DC converter that delivers +3.3V and +5V voltages.
Seasonic was kind to provide this converter to me and I did not have to dismantle the PSU to get to it.
There are two chokes on the face side of it – one for each output voltage – and filtering capacitors. Take note of the size: no wonder that the manufacturers prefer to use such compact cards instead of additional chokes of magnetic amplifiers.
The back side of the module is covered with a heatsink. Without it the converter, squeezed between the cables and the large heatsink of the PSU, would overheat. It is easy to take the heatsink off, though.
You can see two Anpec APW7073 PWM-controllers and seven transistors. This is the control and power sections of the DC-DC converter. It is fully autonomous. You can take this card apart from the PSU and connect +12V to it – and it will yield +5V and +3.3V at the output.
KZE series capacitors from United Chemi-Con are used at the PSU’s output (in the 12V rail, to be exact).