US 8,077,189 B2 · Drive circuit

Abstract

A drive circuit of the present invention is a drive circuit for driving a display element in accordance with grayscale information, which circuit outputs a drive waveform controlled through (i) plural-stepped voltage amplitude modulation and (ii) a pulse width modulation which is settable for each voltage amplitude of the plural-stepped voltage amplitude modulation, the drive circuit including an output control section for (A) latching a pulse width corresponding to a maximum voltage amplitude, according to the grayscale information, which amplitude is one of plural steps of amplitudes of the drive waveform, and which amplitude is to be outputted, so as to control a pulse width of the maximum voltage amplitude, and (B) outputting a maximum pulse width for a voltage amplitude smaller than the maximum voltage amplitude. With this drive circuit, it is possible to realize a drive circuit, whose circuit scale is smaller, for driving a display device including luminescent elements arranged in a matrix manner, the drive circuit generating a drive signal having been controlled by a voltage amplitude modulation (AM) and a pulse width modulation (PWM).

Claims11

Dependent claims

A drive circuit for outputting a drive waveform so as to drive a display element in accordance with grayscale information, the drive waveform being controlled by (i) a plural-stepped voltage amplitude modulation including only one single voltage value data latching section that latches maximum amplitude data from the grayscale information and only one single PWM data latching section that latches pulse width data of the maximum voltage amplitude and (ii) a pulse width modulation which is settable for each voltage amplitude of the plural-stepped voltage amplitude modulation,

wherein among the plural-stepped voltage amplitudes, a smaller voltage amplitude is wider in maximum pulse width;
said drive circuit comprising an output control circuit that controls the drive waveform, at a time of modulating arbitrary grayscale information, said output control circuit (A) latching a signal indicating a pulse width corresponding to a maximum voltage amplitude to be outputted so as to control a pulse width of the maximum voltage amplitude, and (B) outputting a maximum pulse width for a voltage amplitude smaller than the maximum voltage amplitude.

wherein among the plural-stepped voltage amplitudes, a smaller voltage amplitude is wider in maximum pulse width;
wherein said only one single voltage value data latching section, at a time of modulating arbitrary grayscale information, latches first data indicating a maximum voltage amplitude to be outputted;
wherein said only one single PWM data latching section, at the time of modulating arbitrary grayscale information, latches second data indicating a pulse width of the maximum voltage amplitude;
wherein said drive circuit further comprises:
an output-range signal generating section that, at the time of modulating arbitrary grayscale information, generates and outputs an output-range signal in accordance with a maximum pulse width of each voltage amplitude;
and
one or more control sections that output, at the time of modulating arbitrary grayscale information,
(a) a pulse width of the maximum voltage amplitude according to the first data and the second data, and
(b) a maximum pulse width according to the output-range signal, when a voltage amplitude is smaller than the maximum voltage amplitude.

6 more elements

Dependencies are inferred from the claim text.

Drive circuit

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Drive circuit

Life of this patent

Abstract

Claims11