On Tue, Jul 5, 2011 at 2:10 AM, IVP wrote: > Hi all, > > is it possible to make -10V from one or more PIC pins ? The graphic > LCDs I need to use for a project require about -10V @ 5mA for Vee. > The -10V is fairly specific. Even slightly less negative than that and th= e > contrast is no good > > I've looked around and found switched capacitor and capacitor-diode > designs for positive doublers, positive triplers but not greater than uni= ty > inverters. Some of those designs I've used before and found them quite > adequate. A Schottky diode-capacitor inverter is pretty close to -5V > but I think a tripler would be better than a doubler so I can adjust down > to -10V > > For the time being I'm using an SMPS IC to make it but would like to > know if it's possible with discretes, and without an inductor if that's > possible. Unless the omission of an inductor means the inclusion of a > heap of other components > Yes, you can get switched capacitor negative voltage generators which generate either -Vin or -2Vin and stack them. Mouser has a bunch in stock. --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .