555 Timer Generating Negative Voltage

hi, i was following this circuit http://www.csgnetwork.com/ne555c1.html and i think i know how it works... but i'm not sure if it generates enough current.

I need -5v for my 4x40 LCD, so far i've tried this circuit using slightly different valued resistors and capacitors and so far it works, but it doesn't charge/pump fast enough. Is there any way i can enhance this circuit to be able to supply more current using common parts?

Try making the two resistors equal (2K) and reduce the 1nF to 100 pF Use schotkey diodes. Another circuit to try is Maxim MAX1681, just two 1uF capacitors and 5 volt regulator.

As Russlk implies, the 555 is not ideal for this type of circuit. Even at low current loads, you lose 2 diode drops in the conversion process. The 555 also does not have a full rail-to-rail output swing, which causes you to lose even more voltage. With a 1k load, you'll probably only get about -3.6 volts. With a 100 ohm load, it might be more like -2.5 volts. This type of converter works fairly well with higher supply voltages, but for 5 volts, Russlk's suggestion is a much better solution.