Modecom Volcano 750 Gold – mainstream unit with high-end features

Primary side

The primary side of the Volcano 750 Gold begins with two input bridge rectifiers connected in parallel, the GBU1006. Both share the same large primary heatsink also with the PFC and switching transistors and PFC diode. Each bridge can handle up to 10 A at 100 °C and 800 V continuously, or 22 A peak (for 8.3 ms). The voltage drop (which counts for losses) is rated as 1.1 V per diode at 10 A. The PFC coil is similar to what CWT uses, with the winding hidden within the core. Two Infineon IPW50R140CP (23/56 A at 550 V, RDS(On) 0.14 Ω at 14 A and 25 °C, 0.32 Ω at 150 °C) transistors in large TO-247 package switch in the PFC circuit. The diode is a Cree C3D06060 (6/200 A, 600 V, drop of 1.8 V at 8 A and 25 °C, 2.4 V at 175 °C) in TO-220-2 package.

The bulk capacitor that gets charged from the PFC is a Teapo LH 470 μF/450 V. I measured its true capacitance at 409 μF. This series has a minimum lifetime of 2000 hours at the maximum temperature (just 85 °C) and ripple. Well, it could be worse. The switching transistors it feeds are the ROHM Semiconductor R6030ENX (30/80 A, 600 V, 0.13 Ω @25 °C, 0.255 Ω @125 °C) in TO-220F package. The configuration in use is half-bridge, LLC resonant, you can see one of the inductors and the capacitor on the very left. On the picture with the bottom plate you can also see how much wasted space there is in the case. Also you see that the orientation is highly ineffective for cooling as the primary heatsink creates a great barrier for the outcoming air.

As for the driving circuitry, we have Champion Micro silicon here. Firstly, there’s the CM03X to reduce losses, and then the CM6502UHHX to drive the PFC. The resonant switching controller is the usual CM6901X with all the things we are used to (location on the secondary side, three-way switching etc.). This time there is just no isodriver, rather a transformer to carry the driving signal to the transistors. The power silicon on the primary side is seriously overspec’ed for mainstream, that would be three points extra for that.

+5 V stand-by rail

The stand-by rail in the Volcano 750 Gold uses a PWM microchip with integrated transistor, the Xuanyan XY6112P (Chinese only). It carries a small heatsink which is nice. A transformer with a 21mm core is used. Notice more Teapo caps around.

A single diode in a DO-201 package is used for one-way rectification. Two capacitors in parallel are there for filtering. The first one is a Teapo SC 2200/10 and the other 1000/16. At least the first one is in D10 package as the D8 Teapo SC rated (and also real) life sucks. Still, SAMA could have used something decent at least here. You can see on this close picture how dirty the unit is from lacquer, soldering flux and other dust particles.

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