Silverstone SFX Series ST45SF-G 450 W

Silverstone SFX Series ST45SF-G 450 W

Voltage Regulation, Hold-up Time & Inrush Current »

A Look Inside

We strongly suggest a look at this article, which will help you understand the internal components of a PSU much better, before reading this page.

The PCB is very small and overpopulated, so we had to remove some components in order to provide you a better view. The OEM is Enhance and the platform uses a modern design. The primary side has a half-bridge topology with an LLC converter, and the secondary side has synchronous rectification with two DC-DC converters for the generation of the minor rails. All components are of top quality, and only Japanese caps, which tend to last much longer than Chinese caps, are used.

The AC receptacle is installed on a small PCB that holds some of the transient filtering components consisting of one CM choke, two Y caps, and one X cap. We find the second part of the transient filtering stage consisting of one CM choke, two Y caps, one X cap, and a MOV (Metal Oxide Varistor) on the main PCB. The transient filtering stage has all the necessary components to provide adequate protection.

The bridge rectifier is bolted to the same heatsink as the primary switchers. Its model number is GBU1006, and it is powerful enough for the needs of this small PSU.

In the APFC, a single Infineon IPW50R140CP fet is used with the necessary boost diode, here a QH08TZ600. The hold-up cap is provided by Nippon Chemi-Con (450V, 330μF, 105°C, KMR series). The PFC controller, a Champion CM6502 IC, is installed on a vertical PCB that resides on the secondary side.

We find two STP20NM50FD arranged in a half-bridge topology as primary switchers. An LLC converter is also used to further increase efficiency. The LLC resonant controller is a CM6901 IC.

Synchronous design is used on the secondary side, and two IRLB3034PbF fets rectify the +12V rail. We find two NTC thermistors on the heatsink that holds these fets. The first is used by OTP (Over Temperature Protection), while the second is utilized by the fan speed control-circuit. All electrolytic filtering caps on the secondary side are Japanese. Most of them are provided by Chemi-Con (105°C, KY series). We also spotted a couple Rubycon electrolytic caps in the 5VSB fly-back converter and a single Teapo polymer cap.

The tiny DC-DC converters that handle the generation of the minor rails each use an APW7073 PWM controller and a TI 86350D fet.

Housekeeping tasks are handled by a SITI PS223 IC. It supports OCP for two +12V rails and includes OTP.

The standby PWM controller is an STR-A6062H IC.

We find two extra filtering caps on the modular PCB. Soldering quality is good on its rear side.

Soldering quality on the main PCB is quite good. We found two current shunt resistors, an indication for two +12V virtual rails, under the +12V islands.

The cooling fan is provided by Young Lin Tech, and its model number is DFB801512H (12V, 0.17 A, 3000 RPM, 31.2 CFM, 35 dBA). It uses ball bearings and is quite noisy at high RPM.
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