To provide a common voltage regulating circuit of a liquid crystal display device, which facilitates adjusting a common voltage by adjusting the common voltage by software by means of a surplus pulse width modulation signal generated in a liquid crystal peripheral main board, without installing separate hardware such as a variable resistor, and which reduces the possibility of breakage and the manufacturing cost.
The common voltage regulating circuit includes: a data storage means for input of a synchronizing signal, a parallel digital data signal (hereinafter abbreviated as D), a first selection signal, a second selection signal, and storing or output of the synchronizing signal and D according to a combination of the selection signals; a Digital/Analog converting means for converting the externally input parallel D into an analog signal (hereinafter abbreviated as A) in response to the externally input synchronizing signal input when writing in the storage means and output from the means are inhibited, and for converting the parallel D from the storage means into A in response to the synchronizing signal supplied from the storage means when the storage means outputs; and a buffer amplifying means for buffering A converted by the digital/analog converting means and then for output of a common voltage signal.
COPYRIGHT: (C)2011,JPO&INPIT
KIM JIN TAK
OH HANG SEOK
| JPH0882785A | 1996-03-26 | |||
| JPH08122734A | 1996-05-17 | |||
| JPH1093984A | 1998-04-10 |