Rocketfish 700 W Power Supply Review

[Hardware Secrets Team]

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Title: Rocketfish 700 W Power Supply Review
URL: http://www.hardwaresecrets.com/article/556

Here is a snippet:
"Rocketfish and Dynex are two brands owned by Best Buy sold only on their chain of retail stores (and also on their website, of course). Today we are going to review Rocketfish 700 W, a power supply fe..."

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Hardware Secrets Team
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[Travis]

Originally Posted by Hardware Secrets Team

http://www.hardwaresecrets.com/article/556/4

The primary section is controlled two separated integrated circuits, one for the active PFC circuit (ICE2PCS01) and one for driving the switching transistor (i.e. PWM, TNY278P integrated circuit), instead of using just one combo controller as it happens with almost all modern power supplies.

The TNY278P PWM controller chip you saw on the primary side is not the main PWM controller, but the StandBy Power controller.

In traditional half-bridge designs, the main PWM controller chip is usually positioned next to the secondary side to receive voltage feedback directly from the secondary, then the driving transformer is used as the isolator. So the SG6105 you saw on the Dynex 400W and Green Star 450W is the main PWM controller chip (with monitoring/protection circuit integrated).
For that Rocketfish or say Titan 650W, the main controller is AZ7500B
http://www.beareyes.com.cn/2/lib/200...1/DSC_7459.jpg
(AZ7500B is equivalent to KA7500B, or say similar to the TL494 controller
http://www.bcdsemi.com/ProductCenter...ow.aspx?id=205 )

So next time when you autopsy a half-bridge unit, keep an eye on the secondary side and search "494(TL494)", "7500(KA7500B/KA7500C/AZ7500B)", "SG6105" chips. Deer/Solytech loves using an unfamiliar "AT2005B" chip. You can't expect it capable with this strange controller and usually the voltage regulation of this chip is really bad.

Usually Forward design put the PWM chip (ML4800/CM6800G, UC3845B) on the primary side so the PWM signal go through the optical coupler (isolator) and drive the primary MOSFETs. That is often the case in Forward designs.

But still the PWM controller chip can position next to the secondary and receive the feedback signals directly and uses a driving transformer as isolator. Since this approach gets signal faster than optical couplers, it has a faster transcient response.

[Gabriel Torres]

Originally Posted by Travis

The TNY278P PWM controller chip you saw on the primary side is not the main PWM controller, but the StandBy Power controller.

Thanks, I will edit this review to fix this error.

Gabriel.

[Gabriel Torres]

Fixed, thanks!