Driver circuit for driving a plasma display panel driver module incorporating said circuit and method of testing such a module
AssigneeSTMicroelectronics S.r.l.
InventorsCéline Lardeau, Gilles Troussel, Eric Benoit
Life of this patent
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Abstract
A driver circuit for driving a plasma display panel comprising a plurality of cells arranged in a matrix of lines and columns; comprising a set of driver output stages connected to line or column electrodes to which a first electrode of cells of a same line or a same column are connected, respectively. The driver circuit includes a detection device for detecting a short circuit between two or more of the outputs of the driver output stages. It allows to test for alignment faults in the flexible cable connecting together the driver module housing incorporating the driver circuit and the electrodes of the plasma display panel.
Claims20
A driver circuit for driving a plasma display panel formed of cells arranged in a matrix of lines and columns, said driver circuit comprising:
- a set of driver output stages having outputs connected to line or column electrodes which are each connected to a first electrode of cells of a same line or a same column, respectively;
- and
- detection means for detecting a short circuit between two of the outputs of the driver output stages,
- wherein the detection means includes:
- a shunt resistor connected between a first node common to all of the driver output stages and one of a high voltage power supply source and ground;
- and
- comparison means for comparing the voltage drop across the terminals of the shunt resistor with a predetermined threshold, the comparison means delivering a short circuit detection signal based on the result of the comparison, and
- the value of the shunt resistor is low so as not to increase prohibitively the resistance of the driver output stages.
A method of testing a driver module for driving a plasma display panel, the driver module comprising a shunt resistor and a set of driver output stages each having a charging transistor and a discharging transistor, said method comprising the following steps:
- (a) switching to the ON state the charging transistor of a single driver output stage;
- (b) while the charging transistor of the single driver output stage is in the ON state, comparing the value of the voltage drop across the terminals of the shunt resistor with a predetermined threshold;
- and
- (c) in the event of the threshold being exceeded by said voltage drop, generating a short circuit detection signal that indicates a short circuit has been detected.
A plasma display panel comprising:
- a plurality of cells arranged in a matrix of lines and columns;
- and
- a driver circuit comprising:
- a set of driver output stages having outputs connected to line or column electrodes which are each connected to a first electrode of the cells of a same line or a same column, respectively;
- and
- detection means for detecting a short circuit between two of the outputs of the driver output stages,
- wherein the detection means includes:
- a shunt resistor connected between a first node common to all of the driver output stages and one of a high voltage power supply source and ground;
- and
- comparison means for comparing the voltage drop across the terminals of the shunt resistor with a predetermined threshold, the comparison means delivering a short circuit detection signal based on the result of the comparison, and
- the value of the shunt resistor is low so as not to increase prohibitively the resistance of the driver output stages.
Dependencies are inferred from the claim text.