Patent ID: 10854138

Abstract:
An OLED external compensation circuit of a depletion type TFT includes a first thin film transistor, a second thin film transistor, a capacitor, an organic light emitting diode, and a compensation circuit. The second thin film transistor is of a depletion type. The compensation circuit is connected with a first node and a second node. A reset signal is inputted into the compensation circuit. The OLED external compensation circuit is suitable for a depletion type TFT in view of the complicated characteristics of the conventional designs of the depletion type TFT and the OLED external compensation. Other examples of the OLED external compensation circuit of another depletion type TFT are also provided and help reduce the cost of the system chip, thereby achieving cost reduction. The OLED external compensation circuit is compatible with an enhanced TFT circuit of which Vth is positive.