Hello,
We have four narrow rectangular LED PCB's, each one comprising three 1W LEDs. These are double sided PCB's with thermal vias to the bottom layer.
Each PCB is mounted on one of the four faces of a vertical, solid aluminium bar...so we have light shining North, East, South & West from...
Hello,
My company has been putting 1A power LEDs from Cree and Osram in parallel for soome time now.
We only ever use a single current source, and NEVER use series current equalisation resistors or current mirrors.
We have encountered no problems......so why is everyone telling us we are...
Hello,
We are in Brisbane and are having big trouble (and angry customers) with a 6.8W flashing LED light which is a warning light…………
The linear regulator (LM350) keeps blowing up (its case is blown wide open).
Here is the schematic.
http://i48.tinypic.com/2cfxwqq.jpg
(the schematic uses...
Hi,
Why do Class D amplifier designers prefer high voltage supply rails?
Please find attached here two Full-Bridge , Class D amplifier simulations which run in the free simulator called LTspice by linear.com.
Each simulation is of a 4KHz sine wave which gives 100W of power in the speaker...
hello
do you know what are likely values of the Cpole parameter for this optocoupler?
CNY17-2
http://www.vishay.com/docs/83606/cny17.pdf
I am talking about when there is round 3mA flowing in the opto diode.
I need the full tolerance range....i.e min and max of Cpole.
This optocoupler will...
Hello,
Please can you tell if our method of measuring a 500KHz triangular current waveform is accurate?
We are just measuring the voltage across a series sense resistor.
This is the shape of current waveform we are trying to measure the average value of:-
http://i39.tinypic.com/2vwsht1.jpg...
Hello,
I am designing a 330W flyback. (Vin = 180-373VDC, Vout = 80V, 4A)
The problem is that at light load the RCD clamp dissipates about 2.8W.
So i have come up with this switchable RCD clamp.......
http://i43.tinypic.com/2h71de9.jpg
Can you see any problems with this?
Is it OK?
Here is...
Hello,
We need to design an SMPS where efficiency is not that important.
(its for a guitar amplifier)
Max Load = 320W
Vout = +/-40V at 4A
Switching frequency = 66.7KHz.
Vin = 385VDC.
Can we use a Current Mode Flyback in Continuous Mode?
The maximum duty cycle would be 0.25...
Hello,
We want to put a 20W LED tube into a socket for a fluorescent tube with a high frequency, switch mode fluorescent ballast driver.
...we dont want to remove the fluorescent ballast as it would be inconvenient.
Are there any standard solutions for this?
-we still want it to be quite...
Hello,
Is there any company, anywhere in the world, that can provide us with Bode Plots for the SMPS Feedback loop if we send them our SMPS schematic and the specification to which the SMPS is intended.?
We would pay for this.
Hi,
I was recently sacked from my job as a SMPS designer at a new start-up Class D amplifier company
Was i sacked because my voltage mode, full-bridge SMPS with +/-40V rails would have resonated at the output LC resonant frequency when audio pulses at that frequency were drawn from it?
It was...
Regarding Full or half bridge SMPS for audio, (with split +/- output rails) Does any reader know :-
1. What percentage of the output inductors should be coupled.?
2. How to get good transient response , in spite of having coupled inductors.?
(-because coupled inductors improves...
I think that Offline Half-Bridge converters are a complete waste of time....am i right?
The full-bridge is cheaper and better......
FET RMS current will be much higher with a half-bridge than a full bridge, and the half-bridge fets will need to be more pricey with bigger heatsinks.
-this is...
Hello
Please could you tell if an off-the-shelf inductor will be ok for our requirement?
Eg will this inductor be ok….
2209-RC (47uH from Bourns.com)
http://www.bourns.com/data/global/pdfs/2200_series.pdfhttp://www.bourns.com/data/global/pdfs/2200_series.pdf
It is the output inductor on a...
Hi,
I am designing an offline Half-Bridge SMPS at 350W and Vin = 90-265VAC.
(there is no PFC stage)
I am finding that I need to use an ETD44 core , but this seems awfully large.
-I am wondering if it is normal to allow the core to go into saturation (i.e. above 300mT during transients etc?)...
Hello,
We are worried about nuisance tripping of our mains input fuse in our Offline 270W (at the output) SMPS which supplies a guitar amplifier
Vin (min) = 90VAC and uses a voltage doubler mains rectifier.
There is no Power Factor Correction stage, its just a half-bridge SMPS.
The...
Hi,
I have just seen the datasheet for a 180W (peak) offline SMPS which comprises a single stage active power factor corrector...
here it is, its the SMPS180 by Hypex......
http://www.hypex.nl/docs/SMPS180_datasheet.pdf
I cannot , for the life of me, understand why Hypex have made a Power...
