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.


Once we removed the casing, a small, single-sided, PCB greeted us. Apparently the effort to minimize production cost prohibited the use of a double-sided PCB. Thankfully the production cost reduction didn't cause the LLC converter to get scrapped. Its loss less switching is achieved by the main choppers, thus efficiency gets a great boost. Also the heatsinks are quite large, for a Platinum unit with restricted energy/heat dissipation, but apparently they are essential for the fanless operation at lower loads. With its configuration the AP-550 uses all modern tricks to achieve Platinum efficiency and on top of that all caps are pure Japanese, so no compromises have been made in terms of performance and durability.


Usually the transient filtering stage consists of two parts, one located right after the AC receptacle and the second one on the main PCB. In this case the transient filtering components are all located on the main PCB, however their number is sufficient to do the job. So on the main PCB three X caps, two pairs of Y caps (the second after the bridge rectifier) and two CM chokes are installed. To our disappointment there is no MOV, which is responsible for removing dangerous spikes coming from the power grid. Since there is available space on the main PCB we can't help but wonder why Super Flower doesn't install this cheap, but valuable, component in any of their PSUs (so far none of their PSUs we have reviewed had it).


The bridge rectifier (GBU1506) is bolted on the APFC/Primary heatsink and it is quite powerful for the mere 550W capacity of this unit. Right in front of it we find the PFC input cap which filters the high frequency ripple of the fully rectified signal.


In the APFC a single IPW50R140CP fet is used to chop the incoming signal and the boost diode is a CREE C3D06060. The role of the hold up cap plays a large Nippon Chemi-Con (400V, 470μF, 105°C, KMQ series). The PFC controller, an Infineon NCP1653A IC, is housed on a small vertical PCB right next to the PFC transformer. Also between the latter and the hold up cap resides the thermistor responsible for protection against large inrush currents and the relay that cuts the thermistor off, once the start up phase completes. Unfortunately at this time we weren't able to to recognize the model number of the two main choppers, which would require removing the primary heatsink.


The standby PWM controller (Infineon ICE3B0565) resides close to the 5VSB circuit which to our surprise doesn't feature a PI filter. Normally all output rails should have a PI filter.


In the secondary side a synchronous design is used of course and the +12V rail is rectified by four IPP041N04N fets while the minor rails are generated from +12V through two DC-DC converters. All caps in the secondary side are provided by Nippon Chemi-Con and rated at 105°C. On the VRMs (Voltage Regulation Modules) two polymer caps are used.


This daughter-board hosts the LLC resonant controller which also plays the role of the supervisor IC. The specific IC, SF29601, is proprietary and no info is available about it. Apparently Super Flower doesn't want their competitors to learn any details from it.


Soldering quality on the main PCB is decent but certainly it doesn't reach the levels of high end Super Flower models. The good thing is however that we didn't spot any long component leads, which can cause lots of trouble.


The cooling fan has no model description on it and a plain Kingwin badge covers its center. However we took a peek under it and found out that the fan is equipped with ball bearings, something that means increased lifespan compared to a sleeved bearings one.