Capacitive load driving circuit and liquid crystal display

A capacitive load driving circuit for supplying a charging-current to a capacitive load and withdrawing a discharging-current from said capacitive load, comprising:

• an output circuit which comprises a power supply terminal, a ground terminal, and an output terminal connected to said capacitive load, and which performs a charging-current supplying operation of supplying a charging-current from said power supply terminal to said capacitive load and a discharging-current withdrawing operation of withdrawing a discharging-current from said capacitive load to said ground terminal;
• a current generation circuit for selecting, depending on the state of a control input signal, any one of a first state where a first current is supplied to said output circuit so as to cause said output circuit to select said charging-current supplying operation and a second state where a second current is supplied to said output circuit so as to cause said output circuit to select said discharging-current withdrawing operation;
• a charging and discharging control circuit for detecting the electric potential of said capacitive load and thereby controlling and causing said output circuit to continue said charging-current supplying operation until the electric potential of said capacitive load reaches a predetermined upper amplitude limit, to stop said charging-current supplying operation when said electric potential reaches said predetermined upper amplitude limit, to continue said discharging-current withdrawing operation until the electric potential of said capacitive load reaches a predetermined lower amplitude limit, and to stop said discharging-current withdrawing operation when said electric potential reaches said predetermined lower amplitude limit;
• and
• an overcurrent protection circuit for detecting a short circuit between said output terminal and said ground terminal so as to stop or suppress said charging-current supplying operation, and for detecting a short circuit between said output terminal and said power supply terminal so as to stop or suppress said discharging-current withdrawing operation.

A liquid crystal display comprising:

• a liquid crystal display panel common electrode;
• an output circuit which comprises a power supply terminal, a ground terminal, and an output terminal connected to said liquid crystal display panel common electrode, and which performs a charging-current supplying operation of supplying a charging-current from said power supply terminal to said liquid crystal display panel common electrode and a discharging-current withdrawing operation of withdrawing a discharging-current from said liquid crystal display panel common electrode to said ground terminal;
• and
• an overcurrent protection circuit for detecting a short circuit between said output terminal and said ground terminal so as to stop or suppress said charging-current supplying operation, and for detecting a short circuit between said output terminal and said power supply terminal so as to stop or suppress said discharging-current withdrawing operation;
• wherein
• said output circuit selects any one of said charging-current supplying operation and said discharging-current withdrawing operation depending on the state of a control input signal.

A liquid crystal display comprising:

• a liquid crystal display panel common electrode;
• an output circuit which comprises a power supply terminal, a ground terminal, and an output terminal connected to said liquid crystal display panel common electrode, and which performs a charging-current supplying operation of supplying a charging-current from said power supply terminal to said liquid crystal display panel common electrode and a discharging-current withdrawing operation of withdrawing a discharging-current from said liquid crystal display panel common electrode to said ground terminal;
• a current generation circuit for selecting, depending on the state of a control input signal, any one of a first state where a first current is supplied to said output circuit so as to cause said output circuit to select said charging-current supplying operation and a second state where a second current is supplied to said output circuit so as to cause said output circuit to select said discharging-current withdrawing operation;
• a charging and discharging control circuit for detecting the electric potential of said liquid crystal display panel common electrode and thereby controlling and causing said output circuit to continue said charging-current supplying operation until the electric potential of said liquid crystal display panel common electrode reaches a predetermined upper amplitude limit, to stop said charging-current supplying operation when said electric potential reaches said predetermined upper amplitude limit, to continue said discharging-current withdrawing operation until the electric potential of said liquid crystal display panel common electrode reaches a predetermined lower amplitude limit, and to stop said discharging-current withdrawing operation when said electric potential reaches said predetermined lower amplitude limit;
• and
• an overcurrent protection circuit for detecting a short circuit between said output terminal and said ground terminal so as to stop or suppress said charging-current supplying operation, and for detecting a short circuit between said output terminal and said power supply terminal so as to stop or suppress said discharging-current withdrawing operation.