US 2003/0151617 A1 · Reference voltage generation circuit, display driver circuit, display device, and method of generating reference voltage

Abstract

A reference voltage generation circuit outputs multi-valued reference voltages by a ladder resistance circuit connected between a first power supply line to which a power supply voltage on the high potential side is supplied and a second power supply line to which a power supply voltage on the low potential side is supplied. The ladder resistance circuit is formed by connecting a plurality of resistance circuits in series. A first impedance variable circuit of the reference voltage generation circuit changes a first impedance value (resistance value) between the first power supply line and a jth (j is an integer) divided node. A second impedance variable circuit in the reference voltage generation circuit changes a second impedance value (resistance value) between the kth (1≦j<k≦i, k is an integer) divided node and the second power supply line.

Claims29

Dependent claims

A reference voltage generation circuit which generates multi-valued reference voltages for generating grayscale values which are gamma-corrected based on grayscale data, comprising:

a ladder resistance circuit which comprises a plurality of resistance circuits connected in series between first and second power supply lines to which first and second power supply voltages are respectively supplied, and outputs voltages of first to ith (i is an integer of two or more) divided nodes, which are formed by dividing the ladder resistance circuit by the resistance circuits, as first to ith reference voltages;
a first impedance variable circuit which changes a first impedance value which is an impedance between jth (j is an integer) divided node and the first power supply line;
and
a second impedance variable circuit which changes a second impedance value which is an impedance between kth (1≦j<k≦i, k is an integer) divided node and the second power supply line,
wherein the first and second impedance variable circuits decrease the first and second impedance values during a given control period in a drive period based on the grayscale data, and
wherein the first and second impedance variable circuits return the first and second-impedance values to given first and second values after the control period has elapsed.

3 more elements

A reference voltage generation circuit which generates multi-valued reference voltages for generating grayscale values which are gamma-corrected based on grayscale data, comprising:

a ladder resistance circuit which comprises a plurality of resistance circuits connected in series between first and second power supply lines to which first and second power supply voltages are respectively supplied, and outputs voltages of first to ith (i is an integer of two or more) divided nodes, which are formed by dividing the ladder resistance circuit by the resistance circuits, as first to ith reference voltages;
a first switching circuit group which changes impedance of the resistance circuits disposed between the first power supply line and the jth (j is an integer) divided node among the plurality of resistance circuits;
and
a second switching circuit group which changes impedance of the resistance circuits disposed between the second power supply line and the kth (1≦j<k≦i, k is an integer) divided node among the plurality of resistance circuits,
wherein the first and second switching circuit groups decrease the impedance of the resistance circuits during a given control period in a drive period based on the grayscale data, and increase the impedance of the resistance circuits after the control period has elapsed.

2 more elements

Dependencies are inferred from the claim text.

Reference voltage generation circuit, display driver circuit, display device, and method of generating reference voltage

Life of this patent

Reference voltage generation circuit, display driver circuit, display device, and method of generating reference voltage

Life of this patent

Abstract

Claims29