LM2665 Switched Capacitor Voltage Converter

http://www.ti.com/lit/ds/symlink/lm2665.pdf

The LM2665 CMOS charge-pump voltage converter operates as a voltage doubler for an input voltage in the range of 2.5 V to 5.5 V. Two low-cost capacitors and a diode (needed during start-up) are used in this circuit to provide up to 40 mA of output current.