assuming you're using a ucontroller: if you have a spare output pin (one of the PWM pins would be simplest) you can make a capacitor multiplier with a couple of diodes and caps. The lcds generally only draw a mA or so
But I think you'll find it easier to just run a sim or do some trial and error until you get an output with the right voltage and sufficiently small ripple. Increasing the frequency will allow for greater output current, but will be limited by the IO pin output drive capabilities.
proteus does it well the f=voltage seems to forever rise. Even when i lower the rate at which i pulse..
Im assuming i can use this meathod and when i find a suitable speed i can use a cheap 555 timer to accomplish the same speed (pulse) and control it with that....
Im assuming i can use this meathod and when i find a suitable speed i can use a cheap 555 timer to accomplish the same speed (pulse) and control it with that....
A 555 timer doesn't have a rail-rail output, so unless you use a CMOS version you'll need to increase the number of multiplier stages; but otherwise, yes you could use a 555.
If you have a spare IO pin it can be used for free and will be able to supply the required current for an LCD (I'm assuming you use PICs).
heh yeah im toggling from RD6.. on actual circuit it turns my 2.5 volt to alittle above 5 which is awesome!!!!
But i need to get a new pot for contrast control.. for some reason my doesnt work using this meathod. I assume because the current is less anyway. heh i have a 5k pot i think. ill get a 100ohm or something heh thanks alot i learned something new