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 much better. Our main tool for the disassembly of the PSU is a Thermaltronics TMT-9000S soldering and rework station. It is of extreme quality and is equipped with a matching de-soldering gun. With such equipment in hand, breaking apart every PSU is like a walk in the park!


Delta Electronics, the largest and definitely one of the best manufacturers in the world, is this unit's original manufacturer (OEM). The company has unfortunately stopped manufacturing desktop PSUs within the last few years to focus on server-specific ones instead. However, it seems as though Antec managed to persuade them into manufacturing some units under their label. Like its bigger brothers, the HCP-850 utilizes a full-bridge LLC topology, which offers many advantages. These include zero-voltage switching with a varying switching frequency, reduced EMI and RFI noise, and the ability to use higher switching frequencies, which greatly reduces the size of components and lowers cost. The secondary side utilizes a synchronous rectification and two DC-DC converters to generate the minor rails.


The first part of the transient filtering stage is by the AC receptacle and consists of one X and two Y caps. We find the other transient-filtering components, four Y and one X caps, two CM chokes, and an MOV, on the main PCB.


There are two parallel bridge rectifiers. Both are bolted to a dedicated heatsink.


Three AOTF27S60 fets and a CREE C3D08060A boost diode are used in the APFC. The two parallel caps are provided by Nippon Chemi-Con (450V, 390 µF each or 780 µF combined, 105°C, KMQ series), and the PFC controller is mounted to a small PCB along the main PCB's edge. The PCB's controller is a Champion CM6502S IC designed to provide more than 90% efficiency.


The NTC thermistor that protects the unit from high inrush current and its corresponding relay that cuts it off the circuit once the start-up phase completes.


The standby PWM controller is a TNY280PG IC.


The four main switches (STF25NM60ND) are arranged into a full-bridge topology. On top of that, an LLC resonant converter is utilized to provide zero voltage switching and minimize energy losses, which boosts efficiency.


The fets rectifying the +12V rail are directly attached to the main transformer, which greatly reduces energy losses and EMI noise. As you can see in the photographs above, a small heatsink is firmly latches onto the +12V fets to cool them down. A great number of solid capacitors also filter the +12V rail, along with several Nippon Chemi-Con electrolytic caps.


Both DC-DC converters that generate the minor rails are on a PCB right behind the modular one. Two wide bus bars transfer the required power from the +12V rail and ground to this PCB, where two fets, each, handle both minor rails. The PCB is connected to the modular one via three bus bars right on top of it.


Some more electrolytic Chemi-Con caps on the modular PCB further filter ripple on the rails, and several bus bars transfer the +12V rail to the sockets on this PCB. A wide bus bar also provides ground. The bottom sockets directly attach to the main PCB to avoid any additional wiring, which reduces forward voltage drops with high current significantly.


The supervisor IC, a DWA103N, is on a vertical PCB in the secondary side. On the solder side of the same PCB is an AS339 quad voltage comparator. It provides additional OCP channels.


Soldering quality is typical of Delta, top-notch. Delta installed the LLC resonant controller, a Champion CM6901X IC, on this side of the main PCB. The CM6901 operates in PWM mode at low loads and uses FM mode in all other states.


Delta also manufactured the cooling fan. Its model number is AFB1312M (12V, 0.38A), and its relaxed fan profile has it produce very little noise with even high loads. The fan is very quiet with light loads ( it rotates at a mere 600-700 RPM with light loads).