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i'm afraid i don't know why they work, also, i don't know if they will suffer in a noisy environment due to the lack of loop compensation.

thanks for all this great advice! I cannot afford to patent it or anything, and i can't afford to set up myself, so i will be very happy to work as a designer to do these products just like any designer in any other company. By the way, these are mains domestic LED lighting products, specially...

Hello "Just to be clear: the "reflected" power concept is completely wrong. " ....the thing is, if you please see the following article.. http://www.scribd.com/doc/7694921/On-Switch-Mode-Power-Supply-Reference-Manual ..please see page 32, left-hand-side, 2nd paragraph down.. -It clearly...

Hello, I have designed a boost converter with the following specification Vin = 24V Vout = 40V Output power = 10W Switching frequency = 100KHz Continuous conduction mode Output caps = 400uF Output caps ESR = 0.33R Boost inductor = 1mH Ripple current = 10% PWM controller = LT1241 Current mode...

thankyou Zappedagain, Actually , i am wondering now if my uncompensated circuit is maybe OK. the HV9910B uses this uncompensated control and must be OK, i guess... http://www.supertex.com/pdf/datasheets/HV9910B.pdf also, the IRS2541 uses this type of control and must also be OK, agin...

Hello, A circuit that doesn’t work is not nice, but a circuit that does work when it shouldn’t is even worse!………. I am designing mains LED lighting and am using UC3842 PWM controller since it costs just 20 Cents. (Specific LED drivers are too expensive) I have designed two similar current...

You can use slope compensation in a current mode led driver see http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1094,C1766,P81080,D26364 it also has a Vc pin for loop compensation.

Thanks VE1BLL, i am now searching for latest literature on the lowest possible working voltage of a CFL though it does not seem to be available on the web.

Hello, I am writing concerning powering CFLs (Compact Fluorescent Lamps) from the mains. The following App Note from IRF.com shows a fluorescent lamp being powered from the UK mains (240V) .... ...but uses a "valley filler" passive power factor corrector, so the DC bus actually varies from...

Thankyou xnuke.. "I see iterative trial and error, and no satisfactory measure of a margin to instability is proposed." ..the supporters of this time domain analysis would say that they would get sufficient phase margin by changing compensation components until an optimised transient response...

Sorry i forgot to add the background to this post... A few years ago i was at an interview at a branch of a large and well known switcher company and the Engineering Manager (who i notice often contributes technical articles to power electronic periodicals) said that no matter how many...

hello, With these fora having recently debunked myths concerning 1. Power factor correction and efficiency 2. Right half plane zero of boost converter ...i wonder if the situation concerning ensuring the stability of a switcher power supply using time domain (step response) methods only is...

Hello, Sorry if i've missed something here, but Equation 13 (page 21) of the following "Control Loop Cookbook" by Lloyd Dixon http://focus.ti.com/lit/ml/slup113a/slup113a.pdf gives the Boost's and Flyback's RHPZ as having a D in the denominator. Sorry to drag this up again, but can we now...

Hello, I write concerning a flyback PFC stage with L6561. I refer to Figure 16, page 18 of the following app note... http://www.st.com/stonline/products/literature/an/5956.pdf There are feedback compensation components on both primary and secondary sides. Is this unusual? I would have...

Thankyou very much, soryy if this was hijacking the post away from OP.

Hello, I am writing with regard to the RMS capacitor current in the “valley filler” capacitors in an 8W off-line 1 transistor forward converter SMPS. I cannot understand why the LT Spice simulator has calculated this charging current so low. Here is the circuit…… *** FIGURE 1 The “valley...

Hello, Also of interest here is the effect that putting slope compensation in has. -Especially since slope compensation is so often needed in Continuous mode boosts and flybacks. In other words, i wonder what would be the RHPZ frequency when slope compensation is used ? Also, i wonder if...

Thankyou all for replying, VE1BLL....glad to hear yours only cost a dollar....my "1 Watt" LED bulb cost me £9.33 and took 2 weeks to arrive by post (an extra £3.50 packaging = £12.83 total) ....when i took it apart, i found the electronics was pretty much just a 220nF series cap dropper and a...

Hello, I recently purchased a 1 Watt Mains LED light bulb (240V, 50Hz) Using a 220R resistor in series with the live (hot) line i looked at the current entering the bulb using the scope. The bulb is said to be 1 Watt but i calculated that the RMS of the input current waveform was 8.75mA...

Hello, I just took apart a 15W CFL (240V 50Hz) and did a test on the DC bus just after the diode bridge. (This CFL has a mini , 2 transistor SMPS inside it to power the bulb) The Capacitor just after the diode bridge has 110V of (100Hz) ripple on it (it goes from 220V to 330V) I am trying to...