Abstract − In the design of a source driver in an active matrix LCD, of primal importance is the issue of how to restrict the admissible allowance of the RPV (i.e. the ratio of the pixel voltage to the video voltage) of a pixel within a specified narrow range, which determines the transmitted luminance of the pixel. This constraint on the RPV is analyzed in terms of parameters associated with the sampling switch and the sampling pulse, and then by using a minimal number of these parameters a design scheme is described dedicatedly for the sampling switch. Experimental results show that an optimal sampling switch can be attained by the proposed scheme, which gives rise to a source driver with almost 50 % less power consumption than the one by manual design. speed of the source driver in each column, henceforth designated as column driver, is far greater then that of the gate driver in each row, henceforth referred to as row driver. This implies that the column driver acts a principal role to determine the RPV (Ratio of Pixel voltage to Video voltage) of each pixel. 1

Abstract — In the design of an active matrix LCD, the ratio of the pixel voltage to the video voltage, abbreviated to RPV, is an important metric of the performance, since the pixel voltage determines the transmitted luminance of the pixel. Hence, in the design of a source driver circuit for an LCD, of primal importance is the issue of how to restrict the admissible allowance of the RPV of a pixel within a specified narrow range. This constraint on the RPV is analyzed in terms of parameters associated with the sampling switch and the sampling pulse, and then by using a minimal number of these parameters, a design scheme is described dedicatedly for the sampling switch, which finds an optimal sampling switch size and an optimal sampling pulse waveform. Experimental results show that an optimal sampling switch attained by the proposed scheme gives rise to a source driver with almost 50 % less power consumption than the one by manual design. Index Terms — CAD tool, sampling switch, sampling pulse, column driver circuit, active matrix liquid crystal display