IP Library › Granted Patent US 7,242,399
Granted Patent B2
US 7,242,399 · App. 10/298,607 · Granted Jul 10, 2007

Capacitive load drive circuit and plasma display apparatus

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Quick Facts
Patent No.
US 7,242,399
App. No.
10/298,607
Granted
Jul 10, 2007
Kind
B2
Abstract

A low-cost capacitive load drive circuit, in which a reference voltage, a first voltage, and a second voltage are supplied to a capacitive load, and a plasma display apparatus using it, have been disclosed. The capacitive load drive circuit comprises a reference voltage switch the breakdown voltage of which is properly adjusted, a first switch, a reference voltage phase adjusting circuit, and a first phase adjusting circuit, and malfunctions due to the difference in switching characteristics can be prevented from occurring even when devices of different breakdown voltages are used.

Claims (22)

1. A capacitive load drive circuit in which a low potential reference voltage, a first positive voltage, and a second voltage greater than the first voltage are supplied to a capacitive load, comprising:

a first switch that supplies the first voltage to the capacitive load;

a second switch that supplies the low potential reference voltage to the capacitive load;

a first phase adjusting circuit that adjusts the phase of a drive pulse that drives the first switch; and

a second phase adjusting circuit that adjusts the phase of a drive pulse that drives the second switch, wherein the voltage rating of the first switch is less than that of the second switch, and wherein

the first voltage is supplied to the first switch via a first diode, the second voltage is supplied to the first switch via an additional switch and a second diode, and the first switch is driven so as to be always on while the additional switch is on.

2. A capacitive load drive circuit, as set forth in claim 1 , wherein a third switch that supplies a third voltage between the low potential reference voltage and the first voltage to the capacitive load when a voltage to be supplied to the capacitive load is changed from the low potential reference voltage to the first voltage, a fourth switch that supplies the third switch when a voltage to be supplied to the capacitive load is changed from the first voltage to the low potential reference voltage, a third phase adjusting circuit that adjusts the phase of a drive pulse that drives the third switch, and a fourth phase adjusting circuit that adjusts the phase of a drive pulse that drives the fourth switch are provided, and the voltage rating of the third switch is less than that of the fourth switch.

3. A capacitive load drive circuit, as set forth in claim 1 , wherein the first switch and the second switch are composed of power MOSFETs.

4. A capacitive load drive circuit, as set forth in claim 1 , wherein the low potential reference voltage is a negative voltage.

5. A plasma display apparatus in which at least either a sustain electrode drive circuit or a scan electrode drive circuit comprises the capacitive load drive circuit set forth in claim 1 .

6. A capacitive load drive circuit in which a low potential reference voltage, a first positive voltage, and a second voltage greater than the first voltage are supplied to a capacitive load, respectively, comprising:

a first switch that is composed of a power MOSFET and supplies the first voltage to the capacitive load; and

a second switch that is composed of an insulated gate bipolar transistor and supplies the low potential reference voltage to the capacitive load, wherein the voltage rating of the first switch is less than that of the second switch, and wherein

the first voltage is supplied to the first switch via a first diode, the second voltage is supplied to the first switch via an additional switch and a second diode, and the first switch is driven so as to be always on while the additional switch is on.

7. A capacitive load drive circuit, as set forth in claim 6 , further comprising:

a first phase adjusting circuit that adjusts the phase of a drive pulse that drives the first switch; and

a second phase adjusting circuit that adjusts the phase of a drive pulse that drives the second switch.

8. A capacitive load drive circuit in which a reference voltage, a first voltage and a second voltage are supplied to a capacitive load, comprising:

a first switch that supplies the first voltage to the capacitive load and a second switch that supplies the reference voltage to the capacitive load;

a first phase adjusting circuit that adjusts the phase of a drive pulse that drives the first switch; and

a second phase adjusting circuit that adjusts the phase of a drive pulse that drives the second switch, wherein

the first voltage is supplied to the first switch via a first diode, the second voltage is supplied to the first switch via an additional switch and a second diode, and the first switch is driven so as to be always on while the additional switch is on.