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.


We couldn't figure out the OEM of this unit since we didn't encounter this design before. We suspect two things, either Thortech heavily modified a platform of another OEM or they designed a fresh platform. We bet on the first of the above.


The transient filter starts at the AC receptacle with one X and two Y caps. On the main PCB we find the remaining components of the transient filter: two coils, an MOV, one X and two Y caps. There is also a thermistor for inrush current protection along with a bypass relay. Finally the bridge rectifier is a GSIB2580 and is cooled by heatsink.


The TTB800G utilizes interleaved APFC, where two CCM (Continuous Conduction Mode) topologies are working in parallel with a phase difference. This results in lower ripple and gives an efficiency boost. Each of the CCM topologies uses an IXFH44N50P mosfet and a boost diode. The smoothing/reservoir capacitors are provided by Nippon Chemi-Con and are labeled at 105°C (270 & 220µF capacitance respectively, 450V). The APFC controller is a UCC28061 and the daughter board that houses this IC gives also shelter to the resonant controller (L6599). The PSU uses a half bridge resonant topology so along with the LLC resonant converter we find two primary switches (IXFH44N50P). Here we should note the the L6599 IC has the ability to shut down the APFC circuit in case something goes wrong (e.g. if OCP or OTP is triggered). The same IC also shuts down the APFC in low loads, in order to increase efficiency. Voltage drops on APFC's boost diodes have a significant impact to efficiency when the load is low.


In the secondary side four IXTH260N055T2 mosfets regulate +12V. The minor rails are generated through two DC-DC converters. All capacitors in the secondary side are from Nippon Chemi-Con and besides electrolytics we find many polymer ones.


The DC-DC converters are located on the modular PCB, a technique widely used by Seasonic and Enermax. This greatly decreases energy losses since the minor rails are fed directly to the modular sockets without travelling long distances. In each VRM (Voltage Regulation Module) we find an APW7073 PWM controller and two pairs of APM3109 and APM3116 mosfets.


In the above daughter board resides the housekeeping IC, a PS232S and an Atmega ATmega88 8-bit microcontroller which controls the iPower Meter's functions.


Soldering quality overall is quite good with clean joints and short component leads.


The cooling fan is made by Protechnic and is equipped with a plastic baffle to control the air direction. Its model number is MGT13512XB-025 and it can work up to 1800 RPM with 100 CFM. During our tests the max we saw was 1428 RPM while in an older TTB800G sample we have tested it went up to 1578RPM. As it seems Thortech decided to drop its max RPM to decrease the output noise.