US 7,508,367 B2
Drive circuit for improved brightness control in liquid crystal displays and method therefor
Eugene Murphy O'Donnell, Fishers, Ind. (US)
Assigned to Thomson Licensing, Boulogne-Billancourt (France)
Appl. No. 10/182,479
PCT Filed Nov. 29, 2001, PCT No. PCT/US01/44745
§ 371(c)(1), (2), (4) Date Jul. 30, 2002,
PCT Pub. No. WO02/45065, PCT Pub. Date Jun. 06, 2002.
Claims priority of provisional application 60/250196, filed on Nov. 30, 2000.
Prior Publication US 2003/0001811 A1, Jan. 02, 2003
Int. Cl. G09G 3/36 (2006.01)
U.S. Cl. 345—90  [345/92] 12 Claims
OG exemplary drawing
 
1. A display driver for a display unit having a memory element and a liquid crystal cell, comprising:
a first display driver circuit having a first storage capacitor and a first differential amplifier coupled between the first storage capacitor and the liquid crystal cell;
a second display driver circuit having a second storage capacitor and a second differential amplifier coupled between the second storage capacitor and the liquid crystal cell;
a first switching arrangement coupled to the liquid crystal cell and enabling switching the output of the first differential amplifier to the cell during a positive frame and the output of the second differential amplifier to the cell during a negative frame; and
a second switching arrangement coupled to the liquid crystal cell and coupled to at least a supply voltage, wherein the second switching arrangement is controlled by at least one global address line that operates to blank the display unit while leaving unaltered data stored in the first storage capacitor and the second storage capacitor; wherein the second switching arrangement comprises a first transistor configured to force the liquid crystal cell to display white during blanking the display unit and a second transistor configured to force the liquid crystal cell to display black during blanking the display unit.