Display panel driving apparatus having a structure capable of reducing power loss
View Patent ↗A display panel driving circuit for driving a display panel, in which the electric power consumption at the time of the switching can be reduced. The display panel driving apparatus allows the use of a switching device of a low withstanding voltage. A transition voltage generating circuit for shifting a voltage of a DC power source of the driving apparatus is provided. A resonance relay circuit is provided for generating a pulse having a leading edge which rises gradually and a trailing edge which decreases gradually based on the transition voltage and supplying it as a drive pulse to the display panel. A plurality of resonance circuits for driving and exciting capacitive devices of the display panel are provided in a range of different driving potentials. The drive pulse having the leading edge which rises gradually and the trailing edge which decreases gradually is generated by switching each of the resonance circuits by the switching device to make them operative sequentially.
1. A display panel driving apparatus for driving a display panel having a row electrode group, a column electrode group arranged so as to cross said row electrode group, and capacitive light emitting devices each of which is arranged at each of crossing points of said row electrode group and said column electrode group, wherein a drive pulse is supplied to each of said capacitive light emitting devices via an output terminal when driving the display panel, said apparatus comprising:
a first parallel circuit comprising a parallel connection of a series branch constructed by a serial connection of an inductor, a switch, and a diode and a series branch constructed by a serial connection of an inductor, a switch, and a diode whose polarity is opposite to that of said diode;
a second parallel circuit having a same construction as that of said first parallel circuit;
a serial circuit comprising a serial connection of a first switch, a first diode, a second switch, a second diode, a third switch, and a fourth switch;
first, second, and third capacitors;
an output terminal for generating a pulse signal; and
a DC power source having first and second electric potentials,
wherein one end of said first switch is connected to said first electric potential,
the other end of said first switch is connected to an anode of said first diode, one end of said first parallel circuit, and said output terminal,
the other end of said first parallel circuit is connected to one end of said first capacitor,
a cathode of said first diode is connected to one end of said second switch,
the other end of said second switch is connected to an anode of said second diode, the other end of said first capacitor, one end of said third capacitor, and said second electric potential,
a cathode of said second diode is connected to one end of said third switch,
the other end of said third switch is connected to one end of said fourth switch, one end of said second parallel circuit, and said output terminal,
the other end of said second parallel circuit is connected to one end of said second capacitor,
the other end of said fourth switch is connected to the other end of said second capacitor, the other end of said third capacitor, and an earth potential, and
ON/OFF states of each of said switches are controlled based on a control signal which is generated by a predetermined sequence, thereby generating said drive pulse onto said output terminal.
2. An apparatus according to claim 1 , wherein a drain terminal and a source terminal of an FET are used as said switches and said control signal is supplied to a gate terminal of each of said FETs.