6V to 12 volt converter ckt dicrete or IC based

[nikhil arora]

I have a 6V SLA battery from which I want to generate 12V
now battery voltage can vary from 4.8V to 7.2V

few of the IC's from Maxim like max1771,max771 , national's LM2577 etc i have seen. but these are not available in my city.

So I am planning for discrete also.

If you are suggestion any IC plz see that it is very very widely used like LM7805.

I was not able to get LM78S40 universal switching regulator.

 

[justDIY]

how much current do you need at 12v... I assume its more than a few ma?

a simple capacitor charge pump could double your voltage, but only supplies very small current

a lot of the simple single chip boost converters out there have a limit of 6 or 6.5 volts, so your SLA when fully charged, will exceed the design specification ... although perhaps you could use a series diode or two, to drop some of the excess voltage, keeping the voltage within the working range.

visit the Texas Inst website and get some free samples (they claim world wide) of the TPS61040 ... it's very simple to work with and can easily be used to supply up to 400mA at 12 volts from a 2 to 6v supply

 

[nikhil arora]

my current requirement is 1A@12

 

[RadioRon]

1 Amp is getting a bit high for many of the small ICs. We used to build voltage converters using two 2N3055 NPN power transistors in a circuit with a center tapped transformer. The transistors are arranged to oscillate using the primary windings in a push pull configuration, while the secondary feeds a bridge rectifier and DC filter. This old circuit can generate a lot of power, but its a bit more complicated than using an IC boost converter.

Maybe have a look at LM2733 from National. I'm not sure it can handle 1A output though.

RadioRon

 

[justDIY]

MC34063A or 33063A (from TI, ON and others)

buck or boost, 1.5a output, or more with external switch

pretty simple and small 8 pin chip

 

[nikhil arora]

i have sucess fully used mc34063 and i am impressed by simplicity of IC.

Sir I would like to design my own converter using discrete
can any one help me on this