Re: DC boost converter max power ?
Chips like the UC384x series, or MC34063, not to mention the zillions of knockoffs, despite calling them "advanced", simplify the matter of designing these simple DC-DC converters SO much, and they can be had for dirt cheap.
One could argue that designing a discrete version would actually be that much more difficult, due to the interactions between all the circuit elements (not to mention the tolerances).
In the case of the chips i've mentioned, you have all the equations in the datasheets (or worst case, in some application notes). All you'd need to do, to make it (even) easier, would be to plug all the needed formulas into a spreadsheet, and mess around with the component values for the passives needed around those chips (a few resistors & caps).
While technically cheaper, going discrete for a design like this is just making things harder than needed for yourself (not to mention people who are trying to help you). True, the component cost is less, but if you're talking about "profitable for production", you'd also need to factor in the man-hours (and associated cost) for the DESIGN of the thing
All that is if we disregard the fact that, especially in the case of boost converters, you very much DO want overvoltage protection, at the very least, which is a whole different headache if you insist on not using specialised PWM controllers.
Just a quick browse on fleabay:
http://www.ebay.com/itm/10Pcs-Dip-8-...MAAOSwHMJYI0rM
That's TEN pieces for 1.11$AU...
384x ones are a bit more, 5pcs for around the same price:
http://www.ebay.com/itm/5PCS-IC-UC38...sAAOSwg3FUbbBt
Mouser prices are, as you'd expect, a bit higher, but it's a 100% legit source (ie. there shouldn't be any risk of fakes, plus you'd have proof of sourcing the components, for RohS qualifications and whatnot).
34063's start from about 0.46$AU/pc @1pcs, and 384x's (in 8-pin packages) from around 0.79$AU/pc @10pcs, it would seem.
That's the cost argument right out the window. Next?
Chips like the UC384x series, or MC34063, not to mention the zillions of knockoffs, despite calling them "advanced", simplify the matter of designing these simple DC-DC converters SO much, and they can be had for dirt cheap.
One could argue that designing a discrete version would actually be that much more difficult, due to the interactions between all the circuit elements (not to mention the tolerances).
In the case of the chips i've mentioned, you have all the equations in the datasheets (or worst case, in some application notes). All you'd need to do, to make it (even) easier, would be to plug all the needed formulas into a spreadsheet, and mess around with the component values for the passives needed around those chips (a few resistors & caps).
While technically cheaper, going discrete for a design like this is just making things harder than needed for yourself (not to mention people who are trying to help you). True, the component cost is less, but if you're talking about "profitable for production", you'd also need to factor in the man-hours (and associated cost) for the DESIGN of the thing
All that is if we disregard the fact that, especially in the case of boost converters, you very much DO want overvoltage protection, at the very least, which is a whole different headache if you insist on not using specialised PWM controllers.
Just a quick browse on fleabay:
http://www.ebay.com/itm/10Pcs-Dip-8-...MAAOSwHMJYI0rM
That's TEN pieces for 1.11$AU...
384x ones are a bit more, 5pcs for around the same price:
http://www.ebay.com/itm/5PCS-IC-UC38...sAAOSwg3FUbbBt
Mouser prices are, as you'd expect, a bit higher, but it's a 100% legit source (ie. there shouldn't be any risk of fakes, plus you'd have proof of sourcing the components, for RohS qualifications and whatnot).
34063's start from about 0.46$AU/pc @1pcs, and 384x's (in 8-pin packages) from around 0.79$AU/pc @10pcs, it would seem.
That's the cost argument right out the window. Next?
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