Contents
- 1Introduction
- 1.1Packaging and accessories
- 2Connectors & cabling
- 2.1Casing & cooling
- 3Input filtering
- 4Primary side
- 4.1+5 V stand-by rail
- 5Secondary side
- 5.1Build quality
- 6Load testing
- 6.1Loading +5 V SB
- 6.2Voltage hold-up time
- 6.3Combined loading
- 6.4Combined loading ripple
- 6.5Crossloading, overloading
- 6.6Crossloading, overloading ripple
- 6.7Fan speed and temperatures
- 7Conclusion and evaluation
- 7.1Thanks
- 8Addendum - working on the unit
- 8.1Discussion
Primary side
The primary side starts with a bridge rectifier, the GBU806, which has its own aluminium heatsink. It can handle a continuous current of 8 A when heatsinked and running at under the maximum of 100 °C @ 600 V, or 200 A surge (8.3 ms) at 25 °C. The voltage drop is 1 V per diode at 4 A. There are two Infineon IPA50R380CE transistors (9.9/32.4 A at 500 V and 25 °C, Rds(On) is 0.38 Ω at 3.2 A and 25 °C, 0.89 Ω at 150 °C) in a TO-220FP package in the boost-type PFC circuit. The diode in the PFC is an NXP BYC10-600 (10/71 A at 25 °C and 600 V, voltage drop is 2.9 V at 10 A and 25 °C, 1.8 V at 150 °C) in a TO-220-2 package. The PFC coil seems quite undersized to me, it has a small core and uses thin wire, and I think that with this PSU running on 115V mains it’ll get quite hot. The capacitor which is charged from the PFC is a Nippon Chemi-Con KMR Series 330 μF/400 V. This series has lifetime of 2000 hours at 105 °C when running at its maximum ripple spec.
Two Champion Micro ICs are located on the solder side, quite close to each other: The first is the 10pin CM6805BG combo controller which controlls both the PFC and PWM switching. The second is the CM03X which lowers the power consumption when there is no load (or as CM refers to this, “phantom power”). Two Chemi-Con capacitors filter the 6805’s supply power, a KMG 47/50 and a KY 10/50. This IC then controls two Magnachip MDP18N50 transistors (18/72 A at 25 °C and 500 V, Rds(On) 0.27 Ω at 9 A) in a TO-220 package, in a forward configuration. The same thick aluminium heatsink is used for all the power silicon just as in most other Sirtec units, but only this time, it hasn’t been coated in any color.
The main transformer has a 36 mm wide core. Overall I would say that the silicon they’ve used so far is only average by mainstream unit standards; with only slightly less rated PFC silicon but also quite over-spec’d switching silicon, so we shall see how it performs. You may notice some resemblance here to the Silverstone Strider Essential Series 600 W, which is based on Sirtec’s non-modular platform. If you remember, that unit performed quite poorly on the ripple suppression and crossload voltage regulation tests…
+5 V stand-by rail
Some very small 6pin PWM controller is used to drive the stand-by rail. It is labeled 09 D0T, and I have no idea what it is. But it drives a single MOSFET, the Unisonic Technologies 2N60L (2/8 A at 25 °C and 600 V, Rds(On) 5 Ω) in a TO-220F package with no heatsink. The transformer uses a 16mm core.
There’s a single DO-package diode for single-way rectification. Two Chemi-Con caps are used for filtering, both KY Series 1000/10.
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