An organic light emitting diode display is disclosed. In more detail, a biodegradable plastic composition, characterized in that said composition is made by compounding 100 parts by weight of a biodegradable plastic, in particular, an aliphatic type polyester with 0. The excitation signal varies the associated sound produced by the EM musical instrument. The input level-shift circuit is configured to shift a voltage level of an input signal for the digital interface circuit.