PFC Regulator using basic components  - Page 1
Forum section: electronics / projects

author: akhi
author_rank: Newbie
timestamp: August 07, 2023, 02:30:01 pm
content: Dear Community,I would like to design my own PFC Controller using basic components (OPAMP, Comparators, Transistors...). Is it a hard task? Is there any guideline books or application note or maybe better a reference design. I want to replace NCP1654 on my board.

author: jbb
author_rank: Super Contributor
timestamp: August 08, 2023, 04:09:24 am
content: You could in principle, but it would be a lot of work.If you look at the functional block diagram of the NCP1654, it shows some special analog processing around the current control loop: a multiplier for scaling the current sense target into a (rectified) sine wave and a divider for scaling the DC link voltage control signal into a current demand. Those functions can be done with basic parts (eg exponential and logarithmic converters using BJTs) but it would turn into a LOT of parts.Could be an interesting ‘learn about analog’ project. I’m practice I think you’d have a lot of trouble getting anything to operate nicely. For example, noise from the power switching could couple into the analog electronics and make the whole thing go haywire.

author: Konkedout
author_rank: Frequent Contributor
timestamp: August 08, 2023, 04:43:50 am
content: There are a lot of variables. Perhaps the most basic type of PFC boost stage runs in "critical conduction mode." I just googled that and came up with a bunch of "hits" from IC manufacturers describing how it works. One disadvantage of this is a switching frequency which varies down to low (such as maybe 25 KHz) so greater filtering is required. In general there is a lot to go wrong with a PFC pre-regulator, so it is wise to read up as much as possible before diving in.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 08, 2023, 05:18:29 am
content: Not terribly difficult in BCM, though I make no claims that this circuit is anywhere near production-ready.https://www.eevblog.com/forum/projects/power-factor-correction-discrete-control-circuit-(for-bcm)/Tim

author: Terry Bites
author_rank: Super Contributor
timestamp: August 08, 2023, 07:44:49 am
content: Welcome to the reinventing the wheel forum.You can I suppose you might build one but you need to think about the risks.The pfc sits just down stream from the mains rectifier so it needs to be constructed to a very high standard even for a lab demo.Working on it while powered up could be fatal for you and your lab equipment.If you live alone in your own detached house, then go ahead.I wouldn't let a home made pfc out of my sight and I'm a paid up pyromaniac!

author: asis
author_rank: Frequent Contributor
timestamp: August 08, 2023, 09:01:33 am
content: Hi,I suggest that you read a detailed description of the work of PFC:https://techweb.rohm.com/product/power-device/si/si-basic/7389/https://techweb.rohm.com/product/power-device/si/si-basic/7485/https://techweb.rohm.com/product/power-device/si/si-basic/7540/https://techweb.rohm.com/product/power-device/si/si-basic/7834/

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 08, 2023, 01:33:47 pm
content: For learning about it, using low voltage AC from a transformer would make it a lot safer. You can even go a step further and make your own grid tie inverter, which can be thought of as a PFC with the current direction in reverse.