A Look Inside

Before reading this page we strongly suggest to take a look at this article, which will help you understand the internal components of a PSU much better.


The OEM of this unit is Seasonic and currently this is the strongest platform that the company has manufactured (for desktop PCs). It uses cutting edge technology to offer the best possible performance/efficiency including a full bridge LLC-resonant topology, synchronous design on the secondary, integrated to the modular panel DC-DC converters and an innovative cooling system for the mosfets that regulate +12V. To provide you a better view we removed a CM choke from the transient filtering stage and the middle APFC capacitor.


The AC receptacle incorporates a complete line filter from Yunpen (Y015T1) which consists of one X and two Y caps and a CM choke. On the main PCB we also find four Y, two X, one CM choke, one DM choke and an MOV. Right next to the MOV we find an NTC thermistor which provides protection against large inrush currents and in front of the thermistor the large white component is an electromagnetic relay which isolates it from the circuit once it completes its job.


The two parallel rectifier bridges (GBJ 2506) are bolted on a dedicated heatsink. In front of the bridges an X capacitor filters the high frequency ripple of the pulsating DC signal and afterwards we meet the large PFC choke.


In the APFC two IPW60R099CP mosfets along with a CREE C3D10060 boost diode are used. The three parallel hold up caps are provided by Nippon Chemi-Con (330μF, 420V, 105°C, KMR series).


Behind the APFC cap, which we removed, a CM6901 SRC/LLC+SR controller is hiding. This controller provides one FM and two PWM modes. At light loads it operates at PWM mode while at higher loads it switches to FM mode.


An LLC converter is utilized, to provide an efficiency boost, along with a full bridge topology. Four 60R160C6 fets are used as primary choppers.


The standby PWM controller is an ICE2QR4765 and is soldered on the component side of the main PCB.


The mosfets that regulate +12V are located on the solder side of the main PCB and are cooled passively from the casing of the unit and three small heatsinks on the component side of the PCB also assist in their cooling. In total eight BSC018N04LS fets handle +12V. All filtering caps in the secondary are Japan made (Nippon Chemi-Con) and we find many polymers and several electrolytics.


The DC-DC converters responsible for the generation of the minor rails are located on the modular PCB. Their common PWM controller is an APW7159. Each VRM uses three mosfets which unfortunately we weren't able to identify, since their markings were partially erased.


On the face of the modular PCB several polymer caps are soldered. Most of them are used by the VRMs that generate the minor rails while the remaining ones perform additional ripple filtering to +12V.


Housekeeping duties are handled by a PS232F supervisor IC which provides OCP for up to four +12V rails. Nevertheless this unit features a single +12V rail so it uses only one OCP channel.


Soldering quality on the main PCB is very good with nice and clean solders. Also we didn't spot any long component leads, something that greatly pleased us since they can easily cause trouble (shorts).


The seven blade cooling fan is provided by Protechnic Electric and its model number is MGA13512YF-025 (12V, 0.5A). At full speed it is quite noisy, unfortunately. Thankfully it is temperature controlled and due to the low energy dissipation of this unit it will rarely work at full RPM.