This power supply uses a synchronous design on its secondary, meaning that instead of using Schottky rectifiers it uses MOSFET transistors. These transistors generate the +12 V output. The +5 V and +3.3 V outputs are generated through DC-DC converters connected to the +12 V output. These DC-DC converters are located in two daughter boards present on the secondary.

TX950W has five IPA057N08N3 MOSFETs, each one capable of delivering up to 60 A at 25º C or up to 43 A at 100º C in continuous mode, or up to 240 A at 25º C in pulse mode, presenting an RDS(on) of only 5.7 mΩ, which is terrific (a low RDS(on) means that lower power is wasted and thus efficiency is higher).

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Figure 13: Transistors in charge of the rectification.

Each DC-DC converter uses solid aluminum caps and one APW7073 controller and four STD60N3LH5 MOSFETs, each one able to handle up to 48 A at 25º C or 42.8 A at 100º C in continuous mode, or up to 192 A at 25º C at pulse mode with an RDS(on) of only 8 mΩ.

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Figure 14: One of the DC-DC converters.

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Figure 15: One of the DC-DC converters.

This power supply uses a PS229 monitoring integrated circuit, which is in charge of the power supply protections. Unfortunately the manufacturer from this component does not publish the datasheet for this integrated circuit, so we couldn’t check what protections it really supports.

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Figure 16: Monitoring circuit.

Electrolytic capacitors from the secondary are also Japanese, from Chemi-Con and labeled at 105º C, with some of them being solid.