Corsair AX760i 760 W 29

Corsair AX760i 760 W

Voltage Regulation, Hold-up Time & Inrush Current »

A Look Inside & Component Analysis

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

The new AX760i and AX860i are manufactured by Flextronics; the same company that produced the AX1200i. Flextronics is, although they don't have a significant presence in the desktop PSU market, still able to produce products that can easily compete with the more experienced competition (Delta, Seasonic, Enermax etc.) Like its older brother, this unit utilizes a Digital Signal Processor or DSP instead of a conventional PFC/PWM controller and a supervisor IC. This allows for the best possible performance since the DSP is much faster than conventional ICs. DSP makes proper adjustments right on time and does, on top of that, take into account many more parameters. An LLC converter on the primary side and a DC-DC converters, for the generation of the minor rails on the secondary side, further boost efficiency. The unit does, all in all, use the best technology available for commercial PSUs.

The transient filtering stage starts at the AC receptacle with two Y caps and a ferrite ring in which the cables that transfer power to the main PCB are wrapped; this minimizes EMI. The transient filter continues on the main PCB with six Y caps, two X ones, two CM chokes, and an MOV.

The single bridge rectifier, a GSIB 2560L, is bolted onto a dedicated heatsink. It can handle up to 25 A of current, so it is quite strong for the capacity of the PSU.

In the APFC, both fets and the boost diode are covered by metal shields that reduce EMI, so we were unable to identify the components. The hold-up capacitor is a large Chemi-Con (420V, 560μF, 105°C, KMR series). Also right in front of the heatsink that holds the APFC choppers is a thermistor responsible for protection against large inrush currents. The corresponding electromagnetic relay is also installed here.

The two main switchers are also covered by metallic shields which we couldn't remove without desoldering them, something we avoided. To help increase efficiency, a resonant converter is utilized - a proven method that offers noticeable results.

This PCB holds the components that control the APFC circuit and the main switchers. This setup makes the AX760i stand out amongst the crowd of PSUs in its category. A 56F8014 Freescale DSC (Digital Signal Controller) is the brains of the PSU. This controller is, in essence, a hybrid of microcontrollers and DSPs, and combines the advantages of both. Its core is running at 32MHz and is rated at 32 Million Instructions per second (MIPS). It also includes five PWM outputs and two 12-bit Analog-to-Digital Converters (ADCs) that can be programmed using the C programming language. Above the 56F8014 DSC, we find an LM2902K quadruple operational amplifier and, to its left, four optocouplers that provide isolation to the circuit.

In the middle of the PCB, we meet two fully integrated Silicon Lab mixed-signal System-on-a-Chip MCUs that also play the role of a DSP with higher clock speeds. Their model numbers are C8051F310 and C8051F380. Both use the same 8051 µC core, but the core is clocked higher in the C8051F380. The same MCU also includes a USB 2.0 function controller. We also find three more LM2902K quadruple operational amplifiers on the left side of the PCB.

In front of the control board resides a small vertical daughter-board that holds the 5V DC-DC converter. On it, four IPD050N03L fets are installed.

Right next to the main transformer, we find a group of CapXon polymer caps used for filtering the +12V rail. We would highly prefer Japaneses caps here instead of Chinese caps, but Corsair must be pretty confident about the lifespan of these caps since they back the unit up with a seven-year warranty. On the metal bar, above the main transformer and the polymer caps, five thick wires transfer the +12V rail to the modular PCB. The same number of ferrite rings are used on the foregoing wires to suppress high frequency EMI/RFI electronic noise.

The 3.3V DC-DC converter resides between the modular PCB and the metal bar.

This daughter-board houses the 5VSB circuit. On it, we spotted some Rubycon and Nichicon caps.

An Infineon ICE2HS01G resonant controller and a high-voltage L6385E high and low-side driver are installed on the solder side of the main PCB. Soldering quality here is top notch, and the design is very clean.

At the front side of the modular PCB, we find many small FPCAP polymer caps that provide some extra ripple-filtering and two Rubycon electrolytic caps.

The cooling fan is provided by Yate Loon, and a large plastic baffle covers most of its area in order to direct the air towards the back side of the PSU. The fan's model number is D12BH-12 (12 V, 0.3 A, 2300 RPM, 89 CFM, 41 dBA). It uses ball-bearings for increased lifetime and is, at high RPM, quite audible.
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