Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Synchronous Flyback is cheapest way?

Status
Not open for further replies.
T

treez

Guest
Hi,
The attached is a Flyback with vin = 400V (post PFC bus) and vout = 4.5v and iout = 13A.
Its power factor corrected because its for lighting. The loads are multiple single LED linear current regulators.
The synchronous FET is needed due to the high current.
There is secondary side overcurrent sensing with latch off. A microcontroller is then needed to un-latch the overcurrent trip some 500us after overcurrent trip occurs.
Do you see any cheaper way of doing this?


(Ltspice sim and schem attached)
 

Attachments

  • Flyback 4v5 13a.txt
    18.6 KB · Views: 59
  • SCHEM _Flyback 4v5 13A.jpg
    SCHEM _Flyback 4v5 13A.jpg
    181.8 KB · Views: 144
  • schem_Flyback 4v5 13a.pdf
    34.2 KB · Views: 80

What kind of micro is it?

Some of Microchip's micros include opamps, comparators and programmable logic cells. In that case most of the circuitry in the lower right could be integrated into the micro. (This line of parts is like $2 and has fantastic power supply control potential)

https://www.microchip.com/wwwproducts/en/PIC16F1778
 
  • Like
Reactions: treez

    T

    Points: 2
    Helpful Answer Positive Rating
Looks like the latched OCP is all at the board level, though
there's ideal components which are always suspicious.
Why not make it a "motorboat" timeout (one-shot)
instead? If the uC (or whatever) is just going to keep on
resetting the OCP every time, seems like there is no real
intelligence and you could get the same action with a
74AC123, NE555, etc. after the comparator.
 
  • Like
Reactions: treez

    T

    Points: 2
    Helpful Answer Positive Rating
Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top