LT1370 boost converter?

[danielm]

to start i have very little experience with vv units and none at all with boost converters . I was looking a boost converter that can handle at least 4 amps (thats 1.5 ohm at 6v) for triple coil cartos and a wide output voltage range at most 4v min output up to at least 7v max output. i like the PTN04050C but its watt max and amp max is to low by far for what i want it to be able to do so i was searching the internet for a qualifying boost regulator and came across the LT1370. and to my vv noob eyes it look like with some regulation and division and regulation of voltage outputs i can acheive what i am looking for. so can anyone tell me if this would work and/ or another booster that would qualify to my standards? here is the link to the booster LT1370 - 500kHz High Efficiency 6A Switching Regulator - Linear Technology

thanks

 

[asdaq]

Well if you are comfortable adding your own inductor, diodes, resistors and caps to complete the circuit then it looks fine. Maybe someone else is using these and would care to comment?

 

[slimest]

I was looking a boost converter that can handle at least 4 amps (thats 1.5 ohm at 6v)

36/1.5=24 Watts I can imagine your feelings...

 

[jhonutz]

i try to experiment some booster with this IC, it`s not works. Try ltc3872..good booster, much better than lavatube.

 

[CraigHB]

Makers of switching controllers seem to use the term "high efficiency" loosely. Those LT parts are relatively low efficiency controllers since they use current mode control and are asynchronous (they use a diode rectifier). This is a high efficiency controller. Though I would not recommend using that TI part unless you are well versed in the design of switching converters. It's voltage mode which means it requires type III compensation, in other words, its a RPITA to design and tune. It took me quite a bit of simulation and tuning to come up with a reliably stable 30W booster using the TI part. It was worth it though, the booster kicks .... It can drive a 1.2Ω atomizer at 6V with 92% efficiency.

If you want something easy to build, either of the LT parts mentioned would be good ones to use since they're easy to work with, though it comes at a cost. You'll probably get around 85% efficiency at 10W. The boost converter I built with the TPS43000 gets 95% at 10W. Probably not a big deal, but 10% more run time is 10% more run time. It's a reasonable trade off for the simplicity of a current mode asynchronous controller.

Even the simple designs are not always easy to get working well. There's lots of pitfalls in component selection and circuit board layout. It's not always easy to get them to put out as advertised. If someone is not well versed in PCB design and not comfortable with SMD assembly, I would recommend against trying it even with the most simple controller.

 

[asdaq]

Craig that sounds very impressive and certainly beyond my payscale. I think you mentioned before, but did you get the TPS43000 to work in SEPIC mode too?

 

[CraigHB]

Yes, I did actually get a SEPIC to work pretty well with the TPS43000, but the efficiency is just crap, only about 80%. It's mainly because of coupling losses in the dual wound inductor a SEPIC calls for. Also from losses in the bypass capacitor. I've come to the conclusion the best buck-boost topology is the type used, for example, with the LTC3785. The down side is the extra two MOSFETS it requires, takes up more space. I've only been doing boost, but If I ever do a buck-boost, it will be with that controller. Though it probably won't happen since I just don't think its worth the trouble for the limited useful range under 4V that I've since found I have no use for.