Patent ID: 9620053
Date: 2017-04-11
CPC Classifications: G09G

Claim:
1. A threshold voltage sensing circuit of an OLED display device including an OLED, comprising: a sampling capacitor configured to sample a threshold voltage of the OLED; a charge-share capacitor configured to charge-share the voltage sampled in the sampling capacitor; an amplification unit configured to amplify the threshold voltage outputted from the charge-share capacitor; a sensing switch coupled between one terminal of the sampling capacitor and a sensing voltage input terminal to which the threshold voltage is inputted; a second reference voltage switch coupled between the other terminal of the sampling capacitor and one terminal of a second reference voltage source for supplying a second reference voltage; a charge-share switch having one terminal coupled to the one terminal of the sampling capacitor; a first reference voltage switch having one terminal coupled to the other terminal of the sampling capacitor and the other terminal commonly coupled to a first reference voltage source for supplying the first reference voltage and the other terminal of the charge-share capacitor; a charge-sharing operation switch having one terminal coupled to the one terminal of the charge-share capacitor and the other terminal coupled to the other terminal of the charge-share switch; and a comparator configured to compare a variation range of the threshold voltage to a reference value, wherein when the variation range of the threshold voltage is larger than the reference value, the threshold voltage is stored in the sampling capacitor and the charge-share capacitor to make the variation range of the threshold voltage smaller than the reference value, and then transmitted to the amplification unit, wherein when the variation range of the threshold voltage is smaller than the reference value, the threshold voltage is stored in the sampling capacitor.