Sustain driver, sustain control system, and display device

A sustain driver for applying a sustaining voltage pulse to electrodes of a display panel and comprising:

• a floating voltage generating circuit including first to fourth output terminals,
• maintaining said first output terminal at a potential equal to or above a predetermined lower limit,
• maintaining said second output terminal at a potential equal to a constant voltage lower than the potential of said first output terminal,
• maintaining said third output terminal at a constant potential, and
• maintaining said fourth output terminal at a potential equal to a constant voltage lower than the potential of said third output terminal;
• an output circuit comprising
• a high potential power supply terminal connected to an external constant-voltage source and maintained at a predetermined high potential,
• two output transistors connected in series between said high potential power supply terminal and the fourth output terminal of said floating voltage generating circuit, and turned on and off under high and low side output signals received from the outside, and
• a voltage pulse output terminal connected between the node of said two output transistors and the electrodes of said display panel;
• and
• a control circuit comprising:
• a high side power supply terminal connected to the first output terminal of said floating voltage generating circuit,
• a floating power supply terminal connected to the second output terminal of said floating voltage generating circuit,
• a low side power supply terminal connected to the third output terminal of said floating voltage generating circuit,
• a low potential power supply terminal connected to the fourth output terminal of said floating voltage generating circuit,
• an input circuit generating high and low side control signals based on a control signal received from the outside,
• a level shift circuit including a resistance element with a first terminal connected to said high side power supply terminal, and a level shift transistor having an output section, said level shift transistor being connected between a second terminal of said resistance element and said low potential power supply terminal and changing the potential of the second terminal of said resistance element under said high side control signal,
• a high side circuit including an input terminal connected to the second terminal of said resistance element and converting a potential change of said input terminal into said high side output signal, by using the potential difference between said high side and floating power supply terminals,
• a low side circuit converting said low side control signal into said low side output signal, by using the potential difference between said low side and low potential power supply terminals, and
• a bipolar transistor circuit including a collector connected to said high side power supply terminal, an emitter connected to said output section of said level shift transistor, and a base connected to said floating power supply terminal.

A display device comprising:

• a display panel including:
• luminescent cells;
• and electrodes applying a voltage pulse received from the outside to said luminescent cells;
• and
• a sustain driver for applying said sustaining voltage pulse to the electrodes of said display panel and comprising:
• a floating voltage generating circuit including first to fourth output terminals,
• maintaining said first output terminal at a potential equal to or above a predetermined lower limit,
• maintaining said second output terminal at a potential equal to a constant voltage lower than the potential of said first output terminal,
• maintaining said third output terminal at a constant potential, and
• maintaining said fourth output terminal at a potential equal to a constant voltage lower than the potential of said third output terminal;
• an output circuit comprising
• a high potential power supply terminal connected to an external constant-voltage source and maintained at a predetermined high potential,
• two output transistors connected in series between said high potential power supply terminal and the fourth output terminal of said floating voltage generating circuit, and turned on and off under high and low side output signals received from the outside, and
• a voltage pulse output terminal connected between a node of said two output transistors and the electrodes of said display panel;
• and
• a control circuit comprising:
• a high side power supply terminal connected to the first output terminal of said floating voltage generating circuit,
• a floating power supply terminal connected to the second output terminal of said floating voltage generating circuit,
• a low side power supply terminal connected to the third output terminal of said floating voltage generating circuit,
• a low potential power supply terminal connected to the fourth output terminal of said floating voltage generating circuit,
• an input circuit generating high and low side control signals based on a control signal received from the outside,
• a level shift circuit including a resistance element with a first terminal connected to said high side power supply terminal, and a level shift transistor having an output section, said level shift transistor being connected between a second terminal of said resistance element and said low potential power supply terminal and changing the potential of the second terminal of said resistance element under said high side control signal,
• a high side circuit including an input terminal connected to the second terminal of said resistance element and converting a potential change of said input terminal into said high side output signal, by using the potential difference between said high side and floating power supply terminals,
• a low side circuit converting said low side control signal into said low side output signal, by using the potential difference between said low side and low potential power supply terminals, and
• a bipolar transistor circuit including a collector connected to said high side power supply terminal, an emitter connected to said output section of said level shift transistor, and a base connected to said floating power supply terminal.