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TIDA-00127: Power Supply Topology

Jonathon Dahl
Prodigy 70 points
Part Number: TIDA-00127
Other Parts Discussed in Thread: TIDA-00227, UCC28700

I started with a design a power supply for meter the flow when the main request is universal input AC and DC ultra high Voltage range and lower cost.

The main parameters are in a document.

I consider the two topologies

  1. LV boost + HV flyback
  2. HV buck / PFC  + LV flyback

 

I research some sources and  found on TI side TIDA-00127 and TIDA-00227, seems the variant A) is generally preferred.

My question is Is any tried design the variant B) HV buck / PFC  + LV flyback?

 

If I will continue with variant A) I would like to reduce disipated power on HV  switch so it leads to using quasiresonant or some active clamp . So since on the output are two 24V independent outputs there wil be complicated to aply multiple feedback . From this point of view I will prefer primary side regulation like UCC28Cxx

Do you have any recommendations of that? How reduce switching looses?

ultra wide range power.docx

  • 0
    TI__Intellectual 2745 points

    Hi Jonathon,

    You are correct, variant A is preferred.  With variant B, the high-side, HV FET is always passing current.  A 85VAC-265VAC QR or valley switching flyback is very common, low cost and fairly efficient. The valley switching reduces switching loss by turning on with reduce voltage on the switch. Our PMP10468 reference design is an example of an optocoupler-less 24W flyback for this input range. It uses our UCC28700 valley switching flyback controller. This design is a little older, and I recommend upgrading the controller to our newer generation UCC28704 controller.

    thanks,

    Brian