Electrophoresis display appparatus and power control method thereof
View Patent ↗An electrophoresis display apparatus is provided comprising a display panel comprising data lines and gate lines crossing the data lines, a data driving circuit generating data voltages selected among a positive voltage, a negative voltage, and a ground voltage during an image update period and supplying the data voltages to the data lines, a gate driving circuit supplying gate pulses to the gate lines in synchronization with the data voltages during the image update period, and a control logic circuit blocking an output of the data driving circuit based on a variation in one of the positive voltage and a logic power voltage immediately after the image update period, wherein the logic power voltage is lower than the positive voltage and higher than the ground voltage and wherein the ground voltage is lower than the logic power voltage and higher than the negative voltage.
1. An electrophoresis display apparatus comprising:
a display panel comprising data lines and gate lines crossing the data lines;
a data driving circuit generating data voltages selected among a positive voltage, a negative voltage, and a ground voltage during an image update period and supplying the data voltages to the data lines;
a gate driving circuit supplying gate pulses to the gate lines in synchronization with the data voltages during an image update period; and
a control logic circuit blocking an output of the data driving circuit when the positive voltage is lowered to less than a logic power voltage or when the logic power voltage is lowered to less than a preset internal voltage immediately after the image update period, wherein the positive voltage and the logic power voltage are direct current (DC) voltages, and
wherein the logic power voltage is lower than the positive voltage and higher than the ground voltage and wherein the ground voltage is lower than the logic power voltage and higher than the negative voltage.
2. The electrophoresis display apparatus of claim 1 , wherein the data driving circuit comprises,
a first level shifter outputting one of the positive and negative voltages in response to an input data;
a second level shifter outputting one of the positive and negative voltages in response to the input data;
a third level shifter outputting one of the positive and negative voltages in response to the input data;
a first transistor outputting the positive voltage to an output terminal of the data driving circuit in response to an output voltage of the first level shifter;
a second transistor outputting the negative voltage to the output terminal of the data driving circuit in response to an output voltage of the second level shifter;
a third transistor outputting the ground voltage to the output terminal of the data driving circuit in response to an output voltage of the third level shifter;
a first switch turning on/off a current path between an output terminal of the first level shifter and a gate electrode of the first transistor under control of the control logic circuit;
a second switch turning on/off a current path between an output terminal of the second level shifter and a gate electrode of the second transistor under control of the control logic circuit; and
a third switch turning on/off a current path between an output terminal of the third level shifter and a gate electrode of the third transistor under control of the control logic circuit.
3. The electrophoresis display apparatus of claim 2 , wherein the control logic circuit turns off the first, second and third switches when the positive voltage is lowered to less than the logic power voltage.
4. The electrophoresis display apparatus of claim 2 , further comprising:
an internal voltage generating circuit dividing the positive voltage to generate an internal voltage lower than the logic power voltage and higher than the ground voltage, wherein the control logic circuit turns off the first, second and third switches when the logic power voltage is lowered to less than the internal voltage.
5. The electrophoresis display apparatus of claim 1 , wherein the data driving circuit comprises,
a first level shifter outputting one of the positive and negative voltages in response to input data;
a second level shifter outputting one of the positive and negative voltages in response to the input data;
a third level shifter outputting one of the positive and negative voltages in response to the input data;
a first transistor outputting the positive voltage to an output terminal of the data driving circuit in response to an output voltage of the first level shifter;
a second transistor outputting the negative voltage to the output terminal of the data driving circuit in response to an output voltage of the second level shifter;
a third transistor outputting the ground voltage to the output terminal of the data driving circuit in response to an output voltage of the third level shifter;
a first switch turning on/off a current path between an output terminal of the first level shifter and a gate electrode of the first transistor under control of the control logic circuit; and
a switch turning on/off a current path between the transistors and the output terminal of the data driving circuit under control of the control logic circuit.
6. The electrophoresis display apparatus of claim 5 , wherein the control logic circuit turns off the switch when the positive voltage is lowered to less than the logic power voltage.
7. The electrophoresis display apparatus of claim 5 , further comprising:
an internal voltage generating circuit dividing the positive voltage to generate an internal voltage lower than the logic power voltage and higher than the ground voltage, wherein the control logic circuit turns off the switch when the logic power voltage is lowered to less than the internal voltage.
8. The electrophoresis display apparatus of claim 7 , further comprising:
a controller supplying digital data to the data driving circuit and controlling operation timing of the data and gate driving circuits, wherein the control logic circuit and the internal voltage generating circuit are embedded in one of the data driving circuit and the controller.
9. A power control method for an electrophoresis display apparatus comprising a display panel comprising data lines and gate lines crossing the data lines, a data driving circuit generating data voltages selected among a positive voltage, a negative voltage, and a ground voltage during an image update period and supplying the data voltages to the data lines, and a gate driving circuit supplying gate pulses to the gate lines in synchronization with the data voltages during an image update period, the method comprising:
detecting a variation in one of the positive voltage and a logic power voltage immediately after the image update period; and
blocking an output of the data driving circuit when the positive voltage is lowered to less than the logic power voltage or when the logic power voltage is lowered to less than a preset internal voltage, wherein the positive voltage and the logic power voltage are direct current (DC) voltages, and wherein the logic power voltage is lower than the positive voltage and higher than the ground voltage and wherein the ground voltage is lower than the logic power voltage and higher than the negative voltage.
10. The power control method of claim 9 , wherein blocking the output of the data driving circuit is performed when the positive voltage is lowered to less than the logic power voltage.
11. The power control method of claim 9 , further comprising:
generating an internal voltage lower than the logic power voltage and higher than the ground voltage, wherein blocking the output of the data driving circuit is performed when the logic power voltage is lowered to less than the internal voltage.