Due to the high number of people affected by sleep disorders, there is a need for more efficient, drug-free methods to treat these diseases. Brain stimulation has proven to be a potential solution and has gained popularity among scientists in recent years. Several stimulation waveforms have been used; however, the use of a waveform that resembles a brain signal during sleep has not yet been reported. In this work, a multi-tone generator with the ability to reproduce brain signals for a potential brain stimulation system is presented. Its functionality is based on easy-to-integrate square-waves. The proposed generator is designed and simulated in 130nm CMOS technology. It occupies 0.187mm2, and consumes 105uW. It is able to reproduce EEG signals from an open polysomnography database with a percentage root-mean-square difference of 12%.