EEVblog #272 - Manson 9400 40A 3-15V Switchmode PSU Teardown

[si2030]

Hi Dave,

So I watched with avid interest the episode on the above power supply... really helpful and informative... I was wondering though whether you might put an episode together specifically on the TL494 and in particular the way the error amps are being used in this and other supplies for those of us that are challenged in this area. I naturally downloaded the service manual on the above power supply and saw there was quite a bit of circuitry with regard to the error amp and how its been designed. I dont understand this part of the PWM and in particular how to work with error amps in this and other chips of this kind.  Is it possible to do an episode or episodes on the way this aspect of control works?

Kind regards
Simon

[xquercus]

Dave,

Thanks for the follow up blog on power factor correction.  I've never considered this issue in regard to power supply design.

-Jeff

[maxpayne]

Dave,

enjoyed the episode with great pleasure. I also support Si2030's comment. Please ada a tutorial on how to design and stabilize feedback loop and compensate for a stable design on various SMPS topology.

In this Manson SMPS which  topology is used ? its more like half-bridge. I have another question in my mind, why ac coupling is used instead of direct connection  in the primary of main power transformer ?

[jahonen]

AC coupling is there to avoid flux imbalance problems. If there would be even very slight DC component on the switching waveform, then the transformer would be saturated from that DC and switching mosfets would be destroyed. AC coupling is simple way to avoid that without adding much complexity.

Topology surely looks like a half-bridge to me.

Regards,
Janne

[aargee]

Well Dave, does it actually do a wire melting 15V @ 40A?