A Look Inside And Component Analysis
Our main tools for disassembling PSUs are a Thermaltronics soldering and rework station, and a Hakko 808 desoldering gun.
|Transient Filter||6x Y caps, 2x X caps, 2x CM chokes, 1x MOV|
|Inrush Protection||NTC thermistor|
|Bridge Rectifier(s)||1x GBU10V08 (800V, 10A @ 85 °C)|
|APFC MOSFETs||2x Infineon IPP50R399CP (560V, 6A @ 100 °C, 0.399 ohm)|
|APFC Boost Diode||1x STMicroelectronics STTH8S06D (600V, 8A @ 175 °C)|
|Hold-up Cap(s)||1x Nippon Chemi-Con (420V, 270uF, 2000h @ 105 °C, KMR)|
|Main Switchers||2x Infineon IPP50R399CP (560V, 6A @ 100 °C, 0.399 ohm)|
|APFC Controller||Infineon ICE3PCS01|
|Switching Controller||Infineon ICE2HS01G|
|Topology||Primary side: Half Bridge & LLC Resonant Converter Secondary side: Synchronous Rectification & DC-DC converters|
|+12V MOSFETs||2x NXP PSMN2R6-40YS MOSFETs (40V, 100A @ 100 °C, 3.7 ohm) 2x SBR10U45S SBRs (45V, 10A @ 110 °C, 0.54V forward voltage drop @ 125 °C)|
|5V & 3.3V||DC-DC Converters|
|Filtering Capacitors||Electrolytics: Nippon Chemi-Con (KY, KZE, 5000h @ 105 °C), Rubycon (ZLH, 105 °C) Polymers: Enesol|
|Supervisor IC||SITI PS223 (OVP, UVP, OCP, SCP, OTP )|
|Fan Model||ADDA AD1212MB-A70GL (120mm, 12 V, 0.33 A, 80.5 CFM, 38 dB[A], 2050 RPM, double ball-bearing)|
|Standby PWM Controller||Infineon ICE2QR4765|
The platform used by all G-series PSUs is a budget-oriented one compared to Seasonic's KM3 and XP3 designs. At least it's modern and utilizes decent components. In the primary side of the G-450, an LLC resonant converter is used for increased efficiency; in the secondary side, DC-DC converters generate the minor rails. The unit's PCB is quite small and equipped with four heat sinks in total, the largest of which is located in the APFC converter. Seasonic could easily increase this platform's efficiency with some component changes. However, the main purpose of this unit was to decrease production costs rather than to offer the best-performing PSU in its category.
The first part of the transient/EMI filter is located on a small PCB right behind the AC receptacle, and includes two pairs of Y caps, a single X cap and one CM choke. The same filter continues on the main PCB, with two Y caps and one X cap and an additional CM choke. We also spotted an MOV, which is a small and inexpensive component that protects again spikes coming from the main grid. The inrush current protection is handled by an NTC thermistor that is located right next to the bulk cap.
The single bridge rectifier is bolted onto a dedicated heat sink. Its model number is GBU10V08, and it can handle enough current to meet the demands of this PSU. In the APFC converter, two Infineon IPP50R399CP power transistors are used, along with a single STMicroelectronics STTH8S06D boost diode. The bulk cap is provided by Chemi-Con (420V, 270uF, 2000h at 105 °C/221 °F, KMR), and although its capacity looks low, it provides a pretty high hold-up time.
On the left of the PCB shown in the photos above, there are two Infineon ICs. One of them, the ICE3PCS01, controls the APFC converter, while the other one, an ICE2HS01G, controls the primary switchers and the +12V FETs.
Two FETs are used as main switchers, and they are exactly the same as the FETs on the APFC converter. We noticed that Seasonic used FETs with high Rds (on) value in the primary side, which will have a notable effect on this unit's efficiency. The Rds (on) is the Drain - Source On Resistance of a FET; in other words, the total resistance between the drain and the source of a FET during the on state. It is one of the most crucial features of a FET because it provides a clear indication of how much energy can go wasted during switching. The lower the Rds (on) value of a FET, the less energy is wasted, especially under increased loads when lots of amperes pass through it.
In the secondary side, the small heat sink is empty, and its role is to help in the cooling of the +12V FETs and SBRs that are installed under it on the solder side of the PCB. Two NXP PSMN2R6-40YS FETs, along with an equal number of SBR10U45S Schottky barrier diodes, regulate this rail. The SBRs actually replace the embedded diodes of the FETs, offering increased efficiency thanks to their lower voltage drops.
In the secondary side, several Enesol polymer caps filter the rails along with a top-notch mix of Rubycon and Nippon Chemi-Con caps, all rated at 105 °C (221 °F). When it comes to electrolytic caps, we couldn't ask for anything better, and this is why Seasonic is so confident about this platform's reliability, providing a long warranty period.
Both DC-DC converters are installed on a vertical daughterboard. Unfortunately, without some serious desoldering, we cannot identify the components on this board, and we didn't want to risk destroying a fine PSU.
The supervisor IC is a SITI PS223, and it is installed on a small daughterboard. This is one of the few protection ICs supporting over-temperature protection (OTP) out of the box.
The standby PWM controller was partially covered by white glue, but we were able to identify it. It is an Infineon ICE2QR4765, and the 5VSB rectifier, a SBR10U45, is installed on the solder side of the main PCB.
On the front side of the modular PCB, several Chemi-Con and Rubycon electrolytic caps provide some extra ripple filtering. It is always nice to see filtering components on this board.
The soldering quality is quite good, as you can see from the photos above. On top of that, we didn't spot any long component leads, which can cause dangerous shorts.
The cooling fan is provided by Adda, a respected fan manufacturer, and its model number is AD1212MB-A70GL (120mm, 12V, 0.33A, 80.5 CFM, 38 dB[A], 2050 RPM). This fan uses double ball bearings, so it should last for quite a while. Because it is a high-speed fan, Seasonic should have used a relaxed rotational speed profile, especially at mid- and higher loads, instead of staying on the safe side. That's why, with increased loads and even with ambient temperatures below 30 °C (86 °F), the fan spins quickly, outputting a loud noise that won't please many users.