REGISTER | LOGIN
Home    Bloggers    Blogs    Article Archives    Messages    About Us   
Tw  |  Fb  |  In  |  Rss
Dennis Feucht

Seemingly Simple Circuits, Part 6: The Refined Current-Loop Converter Model

Dennis Feucht
D Feucht
D Feucht
6/29/2015 5:41:06 PM
User Rank
Blogger
Re: help regarding flyback current mode design
Nishant,

Before inundating me with CAD details, would you please

1. Describe your circuit;

2. Explain the problem you are having with it.


You can reach me via email through innovatia-dot-com.

50%
50%
nipan
nipan
6/29/2015 7:31:41 AM
User Rank
Newbie
help regarding flyback current mode design
Hello Dennis,

would it be feasible if I could consult you on a flyback current mode control design I am doing for an automotive application?

If your time permits I could share the mathcad design file for your perusal.

Regards,

Nishant.

 

50%
50%
D Feucht
D Feucht
3/18/2015 7:27:58 PM
User Rank
Blogger
Re: Average current
Peak current is more closely related to power transfer in converters operating in DCM. Peak-current control is, of course, used in DCM flybacks, for instance, but in the series which this article finishes, operation deep into CCM is assumed all along. "Deep CCM" is a characterization of the kind of waveform that that has a large static (dc) component and small ripple (ac).

In this case, what determines power transfer is the average or static current value times the Delta current ripple. What is advantageous about CCM is that not only does the ripple size determine transfer power, but the average primary current does too. That means much power can be transferred with little ripple (and noise).

50%
50%
etnapowers
etnapowers
3/18/2015 10:00:29 AM
User Rank
Master
Re: Average current
@Dennis, I agree with you on the importance of average values in the dimensioning of a current loop model, I add that also the peak current plays a role for example to evaluate the charge that is transferred in a cycle of switching to the output capacitance of the converter.

50%
50%
D Feucht
D Feucht
3/17/2015 7:04:51 PM
User Rank
Blogger
Re: Average current
You'll have to explain to me what "dimensioning steps" are.

In the derivations, peak and valley values occur frequently. The main point is that the loop dynamics for the valley current is not the same as for the average current, and it is the response of the average that is usually of interest. The valley point dynamics tell us what is happening at one point in time each cycle. The average tells us something about the response over the entire cycle and is a (piecewise-) continuous measure of the dynamics.

50%
50%
etnapowers
etnapowers
3/17/2015 11:32:57 AM
User Rank
Master
Average current
"This is significant because the current of interest to us in power supply design is the average current. Power-supply ratings are based on it."

 

Right, but I would add many dimensioning steps have to be performed taking into consideration the maximum value of current. Do you agree Dennis?

50%
50%
More Blogs from Dennis Feucht
Previously we looked at the electronics and sensors involved in data acquisition systems (DASs). Now we look at what to do with the raw ADC data once it is acquired.
This is a tutorial presentation of principles of instrumentation that is typically multi-channel, medium to high resolution (12 to 20 bits) and relatively slow - slower than oscilloscopes in sample rate
Continuing the chat from last time, we turn now to a circuit-related topic, that of current waveforms. The typical converter input waveform is shown with a static (dc) component and a ripple (ac) component
Semiconductor companies have now had fully-differential amplifiers in their product lines for a few years, though these amplifiers have been in leading-edge electronics for decades. These diff-amps are differential not only at their input but also at their output, doubling output range.
flash poll
educational resources
 
follow Planet Analog on Twitter
Planet Analog Twitter Feed
like us on facebook
our partners
Planet Analog
About Us     Contact Us     Help     Register     Twitter     Facebook     RSS