StackFET circuit working: DER-712
I was referring to DER-712 and have questions regarding its operation
- I saw the switching wfms given in the document, what determines the voltage distribution between Q3 and innoswitch MOSFET?
- the document says "the voltage across the internal MOSFET of INN3679C IC however will be limited by the TVSClamp VR2". Could you tell the working of the clamping action (when input is higher and lower than 648VDC). How does VR1 work corresponding to VR2 operation.
- What is the use of C27, and why 22pf?
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Could you show zoomed in switching wfms of Q3 and innoswitch MOSFET (VGS, VDS). I want to see how does the switching process occur.
Files
| 첨부 파일 | 파일 크기 |
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| innosw forum_der712_1.jpg | 59.92 KB |
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I'm operating at 2kV. Intended output of PSU 20W.
StackFET seems like a cost effective solution, so I wanted to know its operation to build a prototype
the 1250-1700V offerings are expensive for my application, so i'm leaning towards 650-750V controllers. The controller in DER-712 fit my bill, hence me questions pertaining to the StackFET implementation shown in the DER-712 design
Operating at 2kV input is a very ambitious goal. Losses associated with parasitic capacitances in the transformer and the StackFET chain will eat into your efficiency. If you have more questions about the operation of StackFET, our Power Pros team may be of some assistance:
https://www.power.com/design-support/online-support-request.
What are your power requirements? There are Innoswitch options that allow you to skip using the StackFET approach altogether, as they use a switch with 1250V or 1700V rating.