LEPA G1600-MA 1600 W Review 11

LEPA G1600-MA 1600 W Review

Voltage Regulation & Efficiency »

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 we found the same platform used on MaxRevo and the high capacity Platimax units. The design is unique, very clean and among the best we have ever seen. All components are neatly arranged onto the PCB and very few wires are used, in an effort to restrict energy losses. In the primary side we find a ZVS phase-shifted full-bridge topology while in the secondary synchronous rectification is utilized for the +12V rail along with VRMs for the generation of the minor voltages.


The AC receptacle incorporates a complete line filter (YO15T1, provided by Yunpen) and Enermax decided to reinforce it with two additional Y caps. The transient filter continues on the main PCB with three CM chokes, one X and two Y caps and an MOV.


The single bridge rectifier is bolted on a dedicated heatsink and it is provided by the Japanese company Shindengen. Its model number is LL25XB60 and it can handle up to 25A of current. After the bridge we find the large PFC choke (or boost inductor) and the PFC input capacitor.


In the APFC two SPW35N60C3 fets chop the incoming fully rectified signal.


The three hold up caps are provided by Panasonic/Matsushita (400V, 330μF, 105°C, HC series).


The main choppers are installed in a full bridge topology and with the help of the resonant converter they manage to achieve almost loss-less switching. Their model number is MDF18N50.


Between the APFC and the primary heatsink the thermistor, responsible for protection against large inrush currents during start up, is hiding. There is also a relay to bypass it once it finishes its job.


These two small PCBs house some interesting components. On the right one the PFC controller an ICE2PCS01 and an LM393 voltage comparator, which assists in overvoltage and undervoltage protection, are installed. On the left PCB resides a UCC28950 IC which is the controller responsible for the main switchers and the other IC on this board is a UCC27324, a high speed low-side power mosfet driver.


The main transformer looks small for the capacity of the unit but thanks to its high density it easily copes with the task. The secondary heatsink holds eight IPP015N04N fets which regulate +12V. Afterwards two large toroidal chokes along with a series of ten Rubycon caps (16V, 1500μF, 105°C, ZLK series) filter this rail.


The +12V are transferred to the modular PCB and the smaller PCB that houses the VRMs through several bus bars. This way the use of wires is avoided and voltage drops, especially at high loads, are minimized. The shunt resistors, used by OCP, are soldered on the bottom side of the modular PCB.


The VRMs that generate the minor rails can be found on a smaller PCB, right behind the modular one. On each one an APW7073 PWM controller and four APM2556N fets are used. The polymer caps in the VRMs are provided by Enesol.


On the front left side of the modular PCB resides the protections IC, a PS238 which provides OCP for up to six +12V channels, matching this way the virtual rails that the unit is equipped with.


A TOPSwitch-JX TOP265 integrated of-line switcher controls the 5VSB circuit and ensures the attainment of high efficiency at standby.


Soldering quality on the solder side of the double sided PCB is very good and thankfully we didn't spot any long component leads. Under the area that the +12V are rectified we find a large copper plate which enhances the PCB's conductivity thus decreases voltage drops especially when high currents pass through. Again Lora signs the PCB.


The fan is provided by Adda and according to its model number, ADN512UB-A90, it is equipped with ball bearings. It is rated for 0.44A when operating at 12VDC and in general it is fairly quiet although it has to cool such a monstrous (but highly efficient) unit.
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Nov 22nd, 2024 22:28 EST change timezone

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