Power supply device, liquid crystal display device, and method of supplying power

A power supply device comprising a multi-value voltage generation means for supplying multi-value driving supply voltages, wherein:

• said multi-value voltage generation means comprises a voltage divider means for generating divided voltages at divider terminals thereof, and at least three impedance conversion means connected between said divider terminals and capacitive objects to be driven for converting the impedances of said divided voltages generated at said divider terminals;
• said impedance conversion means includes at least one first impedance conversion means having a drive portion that is capable of drawing in a greater amount of positive charge than a negative charge and at least one second impedance conversion means having a drive portion that is capable of drawing in a greater amount of negative charge than a positive charge, said first impedance conversion means being connected to a first type object to be driven, the polarity of the charge that should be transferred from said first type object to be driven to said first impedance conversion means during the drive period being positive in total, and said second impedance conversion means being connected to a second type object to be driven, the polarity of the charge that should be transferred from said second type object to be driven to said second impedance conversion means during the drive period being negative in total.

A power supply device comprising a multi-value voltage generation means and configured to supply multi-value driving supply voltages from said multi-value voltage generation means, wherein:

• said multi-value voltage generation means comprises a voltage divider means for generating divided voltages at divider terminals thereof;
• a plurality of impedance conversion means connected between said divider terminals and said objects to be driven for converting the impedances of said divided voltages generated at said divider terminals, thus generating multi-value driving supply voltages intended for capacitive objects to be driven;
• and means for controlling said impedance conversion means;
• said impedance conversion means is formed of a voltage-follower connected operational amplifier comprising a differential portion and a drive portion;
• and said drive portion comprises a constant-current source or resistor connected at one end to a first power-source side and at the other end to an output-terminal side, and a drive transistor connected at one end to a second power-source side and at the other end to an output-terminal side;
• and
• said means for controlling said impedance conversion means controls a current to flow through said constant-current source or said resistor of said impedance conversion means only during a fixed period immediately after the rise or fall of the reference clock that is used in driving said object to be driven.

A power supply device comprising a multi-value voltage generation means and configured to supply multi-value driving supply voltages from said multi-value voltage generation means, wherein:

• said multi-value voltage generation means comprises a voltage divider means for generating divided voltages at divider terminals thereof;
• a plurality of impedance conversion means connected between said divider terminals and said objects to be driven for converting the impedances of said divided voltages generated at said divider terminals, thus generating multi-value driving supply voltages intended for capacitive objects to be driven;
• and means for controlling said impedance conversion means;
• said impedance conversion means is formed of a voltage-follower connected operational amplifier comprising a differential portion and a drive portion;
• and said drive portion comprises a constant-current source or resistor connected at one end to a first power-source side and at the other end to an output-terminal side, and a drive transistor connected at one end to a second power-source side and at the other end to an output-terminal side;
• and
• when a frame signal for driving an object to be driven is at a predetermined level, said means for controlling said impedance conversion means puts limitations on a current that flows through said constant-current source or said resistor of said impedance conversion means.

A power supply device comprising a voltage regulation means and a multi-value voltage generation means, and configured to supply multi-value driving supply voltages generated by said multi-value voltage generation means from a regulated voltage generated by said voltage regulation means, wherein:

• said voltage regulation means comprises an operational amplifier which has first and second input terminals and an output terminal for outputting an output voltage based on voltages input to said first and second input terminals;
• a reference voltage source electrically connected to said first input terminal;
• a first resistor electrically connected at one end to said second input terminal of said operational amplifier and at the other end to a fixed potential;
• a second resistor electrically connected at one end to said second input terminal of said operational amplifier and at the other end to said output terminal of said operational amplifier;
• variably controlling means for variably controlling a current which flows through said second resistor;
• said multi-value voltage generation means comprises a voltage divider means for generating divided voltages at divider terminals thereof, and at least three impedance conversion means connected between said divider terminals and capacitive objects to be driven for converting the impedances of said divided voltages generated at said divider terminals;
• said impedance conversion means includes at least one first impedance conversion means having a driven portion that is capable of drawing in a greater amount of positive charge than a negative charge and at least one second impedance conversion means having a drive portion that is capable of drawing in a greater amount of negative charge than a positive charge, said first impedance conversion means being connected to a first type object to be driven, the polarity of the charge that should be transferred from said first type object to be driven to said first impedance conversion means during the drive period being positive in total, and said second impedance conversion means being connected to a second type object to be driven, the polarity of the charge that should be transferred from said second type object to be driven to said second impedance conversion means during the drive period being negative in total.

A liquid crystal display device comprising a voltage regulation means, wherein supply voltages for driving liquid crystal elements are regulated by said voltage regulation means, thus regulating contrast for a liquid crystal display, and wherein:

• said voltage regulation means comprises an operational amplifier which has first and second input terminals and an output terminal for outputting an output voltage based on voltages input to said first and second input terminals;
• a reference voltage source electrically connected to said first input terminal;
• a first resistor electrically connected at one end to said second input terminal of said operational amplifier and at the other end to a fixed potential;
• a second resistor electrically connected at one end to said second input terminal of said operational amplifier and at the other end to said output terminal of said operational amplifier;
• variably controlling means for variably controlling a current which flows through said second resistor.

A liquid crystal display device characterized in comprising a multi-value voltage generation means configured to use a 6-level drive method to drive a liquid crystal element that is an object to be driven, on the basis of multi-value driving supply voltages generated by said multi-value voltage generation means wherein:

• said multi-value voltage generation means comprises a voltage divider means for generating divided voltages at divider terminals thereof;
• a plurality of impedance conversion means connected between said divider terminals and said objects to be driven for converting the impedances of said divided voltages generated at said divider terminals, thus generating multi-value driving supply voltages intended for said objects to be driven;
• and
• supply voltages for driving liquid crystal elements by using said 6-level drive method, said supply voltages termed driving supply voltages at a zero level, a first level, a second level, a third level, a fourth level, and a fifth level from a high-potential side, each of said second and fourth levels of driving supply voltage is generated by a first impedance conversion means having a drive portion that is capable of drawing in a greater amount of positive charge than a negative charge from said object to be driven to said first impedance conversion means, and each of said first and third levels of driving supply voltage is generated by a second impedance conversion means having a drive portion that is capable of drawing in a greater amount of negative charge than a positive charge from said object to be driven to said second impedance conversion means wherein each of said first and said second impedance conversion means is formed of a voltage follower connected operational amplifier comprising a differential portion and a drive portion.