Common voltage regulating circuit of liquid crystal display device

The present invention, in particular, the up / down signal in response to the pulse signal generating means for outputting a pulse width modulation signal for a common voltage to the common adjustment of the voltage adjusting circuit in the liquid crystal display device can be adjusted by software; Smoothing means for smoothing the pulse width modulated signal from the means generating the pulse signal to the DC level; And it characterized in that it comprises an amplifying means for outputting a common voltage signal to a predetermined level, amplifying the smoothed signal from the smoothing means. Accordingly, the present invention can be made, facilitating the modification of the common voltage by making it possible to adjust the common voltage without the additional hardware using the excess pulse width modulation signal generated by the integrated board in software, the variable resistance the do not use while reducing the risk of damage can reduce the manufacturing cost.