US 6,806,861 B1 · Reference gamma compensation voltage generation circuit

Abstract

The object of the present invention is to reduce the number of inputs to LCD driver chips, and to suppress the occurrence of variances between the chips. A ten bit wide binary counter 202 is self activated in synchronization with a system clock. Each of multiple five-step shift registers 200 having ten bit widths stores gamma compensation data received from a PC. Each of multiple comparators 204 compares a binary counter value (X) with a value (Y) stored in a ten bit wide five-step shift register 200, and converts the gamma compensation data into a pulse width. The output of each comparator 204 is latched by each of multiple D-FFs 206 in synchronization with the system clock, and each of multiple time/voltage converters 208 passes the output of a D-FF 206 through an LPF and generates a reference gamma compensation voltage.

Claims5

Dependent claims

A reference gamma compensation voltage generation circuit comprising:

a counter, for system clocks, that generates a clock count values;
a register for storing a set gamma compensation function value;
signal generation means for receiving clock values from the counter and for receiving the compensation function value from the register, and including a comparator for repeatedly comparing clock values from the counter with the compensation function value from the register, and to generate, on the basis of said comparison, a pulse width modulation (PWM) signal wherein, for each gamma compensation cycle, said gamma compensation function value is represented as a pulse width;
and
a voltage generation circuit for employing said PWM signal to generate a reference gamma compensation voltage.

2 more elements

Dependencies are inferred from the claim text.

Reference gamma compensation voltage generation circuit

Life of this patent

Reference gamma compensation voltage generation circuit

Life of this patent

Abstract

Claims5