In this work, the use of different techniques to achieve a fully implantable neurostimulator is analyzed. The target is invasive electrical stimulation for applications requiring a large number of stimulation sites, such as implants to restore vision, e.g. retinal implants. The approaches analyzed are: the use of metal electrodes covered by a conductive polymer, PEDOT, which reduces the electrode impedance; the use of non-rectangular waveforms to save energy during the electrical stimulation; and high circuitry integration in an ASIC to combine the above mentioned techniques. The result is a design with small silicon area and low energy requirements.