Re: Re: Hypex SMPS - When Is It Coming? Alternatives?
Hi Pjotr,
we are working on a SMPS. Our new Class-D engineer is started with a half bridge design, resonant topology and with synchrone rectification.
We have hired again an ex-Philips (NXP...) Engineer.....
Cheers,
Jan-Peter
Pjotr said:
Yup, did put up the same question a few weeks ago here. But it seems JP from Hypex is on holiday
Cheers
Hi Pjotr,
we are working on a SMPS. Our new Class-D engineer is started with a half bridge design, resonant topology and with synchrone rectification.
We have hired again an ex-Philips (NXP...) Engineer.....
Cheers,
Jan-Peter
Hi Jan-Peter,
Thanks for the clarification. Because of the delay and no commercial design really fits my needs for a pair of UCD180’s, I just started my own design including PFC. Resonant topology looks a bit overdone for this application IMHO. There are other and simpler ways.
Glad you found an engineer. Skilled engineers for power electronics are very hard to find at the moment, I know. We have at our company 2 vacancies for such engineers which are hard to fulfil.
Success with the design,
Cheers
Thanks for the clarification. Because of the delay and no commercial design really fits my needs for a pair of UCD180’s, I just started my own design including PFC. Resonant topology looks a bit overdone for this application IMHO. There are other and simpler ways.
Glad you found an engineer. Skilled engineers for power electronics are very hard to find at the moment, I know. We have at our company 2 vacancies for such engineers which are hard to fulfil.
Success with the design,
Cheers
Pjotr said:
Why???
We like to have as low as possible EMI, and high efficiency. For the smaller SMPS we are not suing a PFC to save cost. But a clever design to have an autoranging mains voltage detecting circuit.
Yes I know, it's difficult to get good people. However we are lucky that we get quite easy good people and students....
Cheers,
Jan-Peter
Dag said:So what happened to the Hypex SMPS??
We are working on it. We have evaluated severel different designs in the past, and we are now close to a pre-pre-production version.
Our SMPS will be with PFC, the first version will be rated for 180W at 20Hz. We will rate our SMPS with a power at 20Hz and not 1kHz.
The next will be with double output power, and after this we go for real high power.
Regards,
Jan-Peter
JP, ofcourse they are isolated but sometimes they are not up to the isolation value you will need with a 2pin mains plug without a mains ground pin(like in the living/bedrooms in NL). The KEMA says you'll need a 3KV isolation or 8mm distance between mains and secundary side of the SMPS regarding pcb lines/to chassis with no isolation.
When you have mains ground than the risk of being electrocuted in case of isolation failure or mains surges is minimal.
In other words, would you need a mains ground on your SMPS's to be safe. (on a 2 pin mains(without mains ground) system!!)
When you have mains ground than the risk of being electrocuted in case of isolation failure or mains surges is minimal.
In other words, would you need a mains ground on your SMPS's to be safe. (on a 2 pin mains(without mains ground) system!!)
I think the question might be about something like....
Is it 'Double Insulated'.
Sad to say Jan but if you are going to claim your supply can be operated without mains earth connected and did not know that one then you and your engineer need a slap upside the head.
:-(
If you are going to ignore that one then that probably means you are not going to read or be bothered about the EMC compliance testing.
:-(
Go buy some Standards and bend your head reading them.
DNA
Is it 'Double Insulated'.
Sad to say Jan but if you are going to claim your supply can be operated without mains earth connected and did not know that one then you and your engineer need a slap upside the head.
:-(
If you are going to ignore that one then that probably means you are not going to read or be bothered about the EMC compliance testing.
:-(
Go buy some Standards and bend your head reading them.
DNA
Sigh. There are words such as Class I and Class II and things like basic, double and reinforced. Then there is other stuff about how earthing is applied and bonded.
Other than general creepage and clearance requirements for your wiring, connections and PCB the most important component is the transformer and how it is constructed.
Layers and type of insulation, noise and earth screens and how they are connected and, if necessary fault currents they may have to carry.
It's not a total minefield but the standards are written more along the lines of legal rather than technical documents and it takes a bit to decipher what the accepted practice for your particular piece of equipment might be.
The requirements for a CD player are going to be slightly different to those for the power supply you are designing. The chances are that they can achieve the required performance and incorporate double insulation without trying too hard.
Look on the back of the box, there is probably a square within a square sign close to the mains inlet.
DNA
Other than general creepage and clearance requirements for your wiring, connections and PCB the most important component is the transformer and how it is constructed.
Layers and type of insulation, noise and earth screens and how they are connected and, if necessary fault currents they may have to carry.
It's not a total minefield but the standards are written more along the lines of legal rather than technical documents and it takes a bit to decipher what the accepted practice for your particular piece of equipment might be.
The requirements for a CD player are going to be slightly different to those for the power supply you are designing. The chances are that they can achieve the required performance and incorporate double insulation without trying too hard.
Look on the back of the box, there is probably a square within a square sign close to the mains inlet.
DNA
"Double insulated" requirements are very hard to fulfill. "Double insulated" rated SMPS designs above, say 100W, are quite hard to find.
Jan-Peter doesn't seem to know the standards, but those papers are ugly and dumb and are intended mostly to steal big money from designers and manufacturers and Eliminate Minor Competitors, so who cares? The papers are not even public domain, you have to buy them!!! Then you have to pay huge money to buy compliance.
Furthermore, most of the China-made stuff that we use *everyday* is actually not compliant with any of those safety standards. Most computer power supplies doesn't have any creepage at all between transformer primaries and secondaries. This is not only unreliable but a quite frustrating and unfair competition, but it's being tolerated by certification agencies and authorities.
The one that makes the laws is the same that makes the cheats...
Jan-Peter doesn't seem to know the standards, but those papers are ugly and dumb and are intended mostly to steal big money from designers and manufacturers and Eliminate Minor Competitors, so who cares? The papers are not even public domain, you have to buy them!!! Then you have to pay huge money to buy compliance.
Furthermore, most of the China-made stuff that we use *everyday* is actually not compliant with any of those safety standards. Most computer power supplies doesn't have any creepage at all between transformer primaries and secondaries. This is not only unreliable but a quite frustrating and unfair competition, but it's being tolerated by certification agencies and authorities.
The one that makes the laws is the same that makes the cheats...
Eva said:
You're telling me all the kind of stuff we are already highly aware about. So aware, in fact, that we're quite comfortable that we have the relevant variables under control. Given our understanding of the technical issues I understand your skepticism but I don't think I'm going to allay it simply by *talking* about it. So I suggest we leave it at this and let the product speak for itself when it's finished.
Cheers,
Jan-Peter
If you have a psu(smps) with KEMA label on it(in NL) you're safe. They are only allowed to have this if it complies to the KEMA(like the German TUFF)isolation rules = min. 3KV isolation from mains to chassis or any touchable metal part.
I opened a lot of stuff in my house in all those years to see if there is sufficient isolation on the 2 pin mains psu's but in general thats OK. The only sad thing I often see in the small psu's(switched) is the 2.2nF capacitor from MAINS IN to secundary DC 0V. I always take this out. 8mm creepage on the PCB is ok as is the double choke transformers isolation.
The KEMA has a test station in China also.
I opened a lot of stuff in my house in all those years to see if there is sufficient isolation on the 2 pin mains psu's but in general thats OK. The only sad thing I often see in the small psu's(switched) is the 2.2nF capacitor from MAINS IN to secundary DC 0V. I always take this out. 8mm creepage on the PCB is ok as is the double choke transformers isolation.
The KEMA has a test station in China also.
If you take that cap out, it's highly likely that the PSU will no longer meet the conducted-noise emissions requirements. I've designed three off-line SMPSUs in the past 4 years that have gone into equipment that had to be fully EMC tested, and in all cases, meeting the conducted noise emission and susceptibility proved to be hard. Admitedly, it doesn't help that the company I design for always designs equipment to meet the Class-B limits for emissions, and the Class-A limits for susceptibility. (This combination makes it hardest for us for both!).
Meeting the EN60950 safety requirements is trivial compared with the EMC, especially now that EN60950-compliant triple-insulated wire is available to ease the isolation-barrier problems on the transformer bobbin.
Meeting the EN60950 safety requirements is trivial compared with the EMC, especially now that EN60950-compliant triple-insulated wire is available to ease the isolation-barrier problems on the transformer bobbin.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.