I had incandescents in every room in the house with the exception of the kitchen and family room where we had conventional fluorescence. we had been in the house 8 years and changed only one incandescent globe. About 4 years ago we were given a bunch of GE CFL's to replace the standard size incandescents and have replaced 3 of them already. Given the increased price of them and the greater carbon footprint I would suggest that CFL's only make financial and environmental sense in locations where they run for hours at a time, because they certainly DO NOT last longer in terms of time since first turn on as our experiment has shown. I believe the CFL industry has pulled the wool over everyone's eyes on this one. As they say, the proof of the pudding.....
I agree with you, and preheating increases life of tube considerately but it also consumes more energy, in a CFL, a few milliwats plus the added cost...and in buildings, where common areas are lit by CFLs, the PFC becomes very important because it adds up to a lot of noise and distortion, but I haven´t seen the first CFL witha PCF controller
It would be interesting to know what issues this IC was intended to address, save for IC-controlled inductor saturation. Few commodity CFL incandescent lamp replacements actually use an IC, while demonstrating operation over a considerably wider operating input voltage range, without apparent resonant inductor saturation issues. Perhaps this is more of an issue at 240VAC?
Does the IC allow cooler operation? Generate less noise or distortion? Avoid the use of high voltage electrolytic or low temperature film capacitors? Cost less? Use mercury-free tubes? Allow hands-free assembly? Has NXP missed the boat on this one?
There are 4 major things (problems) that are basic for CFLs:
1. Colour - so called light temperature should always be below 4000K (nice sunny colour for domestic use) unless you're a fan of horror movies.
2. Warm start - if you want to enjoy your energy efficient light for long make sure you buy one with this feature. They're easy to spot - the warm start ones take longer to light up (about 1 sec) and the filaments light up first. This allows the gas to be heated inside to lower the ignition voltage. Most of the CFLs on the market DO NOT have it - manufacturers are sparing 30cc PTC posistor.
3. Position - if you place your CFL upside down it will live shorter because of the temperature - hot air tends to go up and if the electronics PCB is higher then the light tube then it heats more. The last CFLs I bought have even a warning on the box.
4. All (to my knowledge) CFLs at the market now DO NOT have any power factor correction therefore they draw non-sinusoidal highly distorted current (spikes with amplitude 5 times higher then RMS value). That is normally not a problem for a domestic lighting but may be a problem in a big building (neutrals wires overheating in 3 phase system) and makes the grid a bit less effective. Fortunately power drawn by CFLs (domestic) are just a small percentage of the whole power to make it a significant problem.
Blog Doing Math in FPGAs Tom Burke 12 comments For a recent project, I explored doing "real" (that is, non-integer) math on a Spartan 3 FPGA. FPGAs, by their nature, do integer math. That is, there's no floating-point ...