SMPS Design - Power Integrations TOP264EG - Review

Hi All,

I am trying to design a multi output SMPS deriving the following rails.

1. +3.3V - 1A, Continuous Operating Current - 300mA. Minimum Idle Current - 150mA. Regulation less than 5%.
2. +5V - 2A, Idle Current - 200mA, Continuous Operating Current - 1A. Regulation less than 5%.
3. +12V - 0.5A, Idle Current - 50mA, Continuous Operating Current - 300mA, Regulation about 10%
4. -5V - 0.5A - Idle Current - 25mA, Continuous Operating Current - 200mA

I have attached the schematic for this design along with board design. The SMPS will power electronics required for my custom application. All are resistive loads and do not have any inductive loads. Board design is done in accordance with recommended board layout by PIExpert.

1. Can somebody review the schematic and board designs? This is my first SMPS design and hence have played safe w.r.t cross regulation by including LDO's at the output.
2. I have added some LED's at the output to indicate power in rail, and can this act as the bleeder to discharge the capacitor charge once SMPS is turned off or should I add a separate circuit for this?

Regards,
Manju

you don't need "bleeder" ..voltage is too low at output to be dangerous, in any case, the leakage current of the electrolytics will bleed it down,

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Hello,
That’s a lot of secondaries that you’ve got there, and are you sure that the ee25 bobbin is actually deep enough to be able to take all those layers and the tape between them?……I cannot find a datasheet for the EE25 core, but the EFD25 core is surely not much different in size, and its bobbin is only 3.85mm deep…….i doubt that is enough for all that you want to wind on it?…..its going to be horrendously tight


**broken link removed**

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You might well be better off just having a single secondary, and feeding off it with inverting and non-inverting smps’s to get your rails….at those low powers there are IC’s which can do the FET and control on a single ic