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hi,liuyonggen_1
have you find the answer?i think it is (1-d) that the RHP zero."a more accurate current-control model" has given the expression of boost converter.,but i dont know how to get the expression
ωz,rhp=R(1-D)²/L
Maybe the article"a new small-signal model for current-mode control" talk about the question,but i can't find the artile.
reguards
sissi
Hi Sissi,
It can be simulated by simulink/pspice for both ac and transisent reponse (see Appendix B, Fundmental of Power Electronics by Erickson & Maksimovic) However, it does not have switch effect. It is also possible to bulid swich/state model in simulink and pspice/cadence. For the current mode control for boost, it is written down in ch. 12 at the same book.
hi,all
i have two questions.
1.what is the quiescent current of a boost converter? how to understand that condition:no switching?
2.what is the effiency? how to calculate?
sissi
1.what is the quiescent current of a boost converter? how to understand that condition:no switching?
Ans: The quiescent current is the current which is drawn from the supply when the DC DC converter is in the idle mode ie no switching activity .You may be having one control signal to switch and bias the current to the blocks,that signal should be zero ie low.
2.what is the effiency? how to calculate
Efficiency of the converter is normally calculated by = Pout/Pin= Vout * Iout/Vin * Iin
hi,kumard35b
i don't know what meaning it is"You may be having one control signal to switch and bias the current to the blocks,that signal should be zero ie low. "
i know the expression,but i don't know what is Vin * Iin incuding.could you explain clearly?
sissi
hi,I am doing a project on boost DC to DC ,Vin=2.8V--5.5V, Vout=10V Imax=250mA
my question is about slope compensation.
m1=vin/L ,-m2=(vout-vin-Vd)/L ,vin is not constant,so how to compensate the circuit to canceal the sub-H osc?
in buck ,ma>=1/2 m2, how to set ma in my design?
another question:
how to design a V to I converter in the slope compensation circuit?
boost:
worst case occurs @ maximum vout/vin,
ie @max. output mimum input situation
in Robert W. Erickson book "Fundamentals of Power Electronics" fomula(12.25)
x=(m2-ma)/(m1+ma)= (y-a)/(1+a) <1
if a>(y-1)/2 (where y=m2/m1, a=ma/m1,)
the fomula can determine min. slop u need.
2.
u can ref. the paper
"A 1-V Integrated Current-Mode Boost Converter in Standard 3.3/5-V CMOS Technologies" ,Philip K. T. Mok, but, the paper focus on low voltage solution,
so, you may be have better solution for V-I converter..
if helpful,pls let me know!!
dc-dc is a feedback system, so stability is a primary question. if there is a switch, perhaps building model that linearizes switch is necessary and ac simulation is done. question: how to build model can be done ac simulation?
thanks!
Hi,
I have a little experience in dc-dc boost converter.You may use the matlab simulink to do the behaviour level simulation and spice to simulate your circuits.
To sense the current using a resistor is a simple way. In a real chip there are still some other aspects to consider. Which control scheme are you using?
As for a white LED driver with current regulated, you may take fairchild's fan5608 as a reference. It's a good product.
Thank you for raise such a top. I'll learn much during the discussion.
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