[braillediver]

Cleaning up here at work I found some LTC1144 “Switched-Capacitor Wide Input Range Voltage Converter with Shutdown”. The Data sheet claims “Simple Conversion of 15V to -15V Supply”.

http://www.linear.com/prod/datasheet.html?datasheet=246

Has anyone ever used these? Seems like an easy way to get + and – from a single source?

I’m gonna play with these this weekend.

 

[aeberbach]

I've used a Cosel ZW30515 - similar thing except that this one needs no external caps. 5V in, +- 15V out. Headroom use the same component in a couple of their designs. Keep it as far away from other components as physically possible and make sure everything is grounded/shielded as appropriate, they use an osciallator internally. The ZW30515 comes in a can so it shields itself somewhat.

 

[jasong]

Seems like a bit of a communication problem here...the datasheet for LTC1144 says that it takes 15v (for instance) and converts to
-15 v, not 15 to +-15.

> It performs supply voltage conversion from positive to negative from an input range of 2V to 18V, resulting in complementary output voltages of -2V to -18V<


-jasong

 

[CaptBubba]

yeah, and look at that graph at the bottom. The output voltage will be all over the place when using an amplifier, because the current drawn isn't constant. I don't see that as being a good thing. Or maybe I am wrong and just seeing problems where none exist.

 

[braillediver]

Thanks this input will save me some time.

I also found some OP27's. The data sheet has a phono pre-amp schematic. The best part is the References at the end

http://www.analog.com/productSelection/pdf/OP27_a.pdf

Jung, Lip****z I haven't read the books but the names are familiar.

 

[tangent]

That's what the power capacitors are for -- to smooth out the current demand on the power supply.

 

[Joobu]

Capacitors can smooth out transients but in terms of switchers, inductor-less (capacitor) voltage converters typically have poor load regulation. Load variations over several mA can seriously affect the voltage. The way I see it, all switchers are a headache unless absolutely necessary (weight, size).