I. Introduction
In the last decade, because of the advantages of fast response time, wide viewing angle, high contrast ratio and low power consumption, active-matrix organic light-emitting diode (AMOLED) displays were quickly received by industries such as Mobile Phone, Tablet and TV field [1], [2]. Combined with Thin-film-transistor (TFT) integrated gate driver on array (GOA) technology, a narrow bezel design and low costs display could be achieved[3~5]. But as the threshold voltage (Vth) variation, especially the driving TFTs’s Vth shifting, The brightness of the panel will become uneven. In order to solve this problem, many compensation schemes have been proposed[6-12], which can be divided into two categories, external compensation and internal compensation.Where the internal compensation can achieve the function-real-time compensation.