Level converter circuit, display device and portable terminal device

A display device comprising a pixel unit having pixels arrayed in a matrix on a board, driving means provided on the same board as the pixel unit and adapted for driving the pixels of the pixel unit, and a level converter circuit for performing level conversion of a timing pulse of a first voltage amplitude inputted from outside the board to a second voltage amplitude and supplying the level-converted timing pulse to the driving means,

• the level converter circuit comprising:
• a first circuit that is constantly in an operating state and performs level conversion of a first timing pulse that becomes active during a horizontal blanking period of an image signal, from the first voltage amplitude to the second voltage amplitude;
• and
• a second circuit that is in an operating state during an active period of the first timing pulse using the first timing pulse after the level conversion by the first circuit and performs level conversion of a second timing pulse from the first voltage amplitude to the second voltage amplitude wherein the level converter circuit further comprises:
• a timing control circuit for generating a control pulse that becomes active during the active period of the first timing pulse on the basis of the first and second timing pulses after the level conversion by the first and second circuits;
• and
• a third circuit that is in an operating state during an active period of the control pulse using the control pulse and performs level conversion of a third timing pulse from the first voltage amplitude to the second voltage amplitude.

A display device comprising:

• a pixel unit having pixels arrayed in a matrix on a board and having signal lines arranged for each row of the pixel array;
• selection means provided on the same board as the pixel unit and adapted for time-divisionally selecting a set of plural signal lines and supplying a signal thereto;
• and
• level conversion means for converting a selector pulse with a first voltage amplitude inputted from outside the board to a second voltage amplitude and supplying the converted selector pulse to the selection means, the level conversion means being inactive when the selection means is in a non-selection state and wherein the level conversion means has a first level shifter that becomes active in response to an enable pulse allowing supply of a signal to the signal lines and performs level shift of a first shift pulse, a second level shifter that becomes active at timing of vanishing of the first shift pulse level-shifted by the first level shifter and performs level shift of a second shift pulse, and a third level shifter that becomes active at timing of vanishing of the second shift pulse level-shifted by the second level shifter and performs level shift of a third shift pulse,
• the first level shifter becoming inactive at timing of generation of the second shift pulse, the second level shifter becoming inactive at timing of generation of the third shift pulse, and the third level shifter becoming inactive at timing of vanishing of the enable pulse.

A portable telephone device using, as an output display unit, a display device comprising a pixel unit having pixels arrayed in a matrix on a board, driving means provided on the same board as the pixel unit and adapted for driving the pixels of the pixel unit, and a level converter circuit for performing level conversion of a timing pulse of a first voltage amplitude inputted from outside the board to a second voltage amplitude and supplying the level-converted timing pulse to the driving means,

• the level converter circuit comprising:
• a first circuit that is constantly in an operating state and performs level conversion of a first timing pulse that becomes active during a horizontal blanking period of an image signal, from the first voltage amplitude to the second voltage amplitude;
• and
• a second circuit that is in an operating state during an active period of the first timing pulse using the first timing pulse after the level conversion b the first circuit and performs level conversion of a second timing pulse from the first voltage amplitude to the second voltage amplitude, and wherein the level converter circuit further comprises:
• a timing control circuit for generating a control pulse that becomes active during the active period of the first timing pulse on the basis of the first and second timing pulses after the level conversion by the first and second circuits;
• and
• a third circuit that is in an operating state during an active period of the control pulse using the control pulse and performs level conversion of a third timing pulse from the first voltage amplitude to the second voltage amplitude.

A portable telephone device having an output display unit and using a liquid crystal display device as the output display unit,

• the liquid crystal display device comprising:
• a pixel unit having pixels arrayed in a matrix on a board and having signal lines arranged for each row of the pixel array;
• selection means provided on the same board as the pixel unit and adapted for time-divisionally selecting a set of plural signal lines and supplying a signal thereto;
• and
• level conversion means for converting a selector pulse with a first voltage amplitude inputted from outside the board to a second voltage amplitude and supplying the converted selector pulse to the selection means, the level conversion means being inactive when the selection means is in a non-selection state and wherein the level conversion means has a first level shifter that becomes active in response to an enable pulse allowing supply of a signal to the signal lines and performs level shift of a first shift pulse, a second level shifter that becomes active at timing of vanishing of the first shift pulse level-shifted by the first level shifter and performs level shift of a second shift pulse, and a third level shifter that becomes active at timing of vanishing of the second shift pulse level-shifted by the second level shifter and performs level shift of a third shift pulse,
• the first level shifter becoming inactive at timing of generation of the second shift pulse, the second level shifter becoming inactive at timing of generation of the third shift pulse, and the third level shifter becoming inactive at timing of vanishing of the enable pulse.