Apparatus and system using active-matrix electrowetting-on-dielectric (AM-EWOD)
An apparatus including a pixel electrode circuit is provided. The pixel electrode circuit includes a first switch, a second switch, a first-type transistor, a first second-type transistor, and a second second-type transistor. The first switch and the second switch are respectively controlled by a first control signal and a second control signal. The first-type transistor includes a gate electrically connected to a first node, a first terminal connected to a first power supply voltage, and a second terminal connected to a third node. The first second-type transistor includes a gate electrically connected to a second node, a first terminal connected to a second power supply voltage, and a second terminal connected to the third node. The second second-type transistor includes a gate electrically connected to the second node, a first terminal being grounded, and a second terminal providing an output voltage.
1. An apparatus, comprising:
a pixel electrode circuit, comprising:
a first switch, controlled by a first control signal, the first switch comprising a first terminal electrically connected to an input voltage, and a second terminal electrically connected to a first node;
a cascode inverter stage, coupled between the first node and a second node;
a first transistor, having a gate electrically connected to a third node, a first terminal connected to a fourth node, and a second terminal connected to a fifth node, the first transistor being a first-type transistor;
a second transistor, having a gate electrically connected to the second node, a first terminal being grounded, and a second terminal connected to the fourth node, the second transistor being a second-type transistor; and
a first capacitor and a second capacitor, wherein the first capacitor is coupled between the first node and a ground, and the fifth node is coupled to an alternating-current (AC) voltage through the second capacitor.
2. The apparatus of claim 1 , wherein the first-type transistor is a P-type transistor, and the second-type transistor is an N-type transistor.
3. The apparatus of claim 1 , wherein the cascode inverter stage comprises:
a first inverter, having an input terminal connected to the first node, and an output terminal connected to the third node; and
a second inverter, having an input terminal connected to the third node, and an output terminal connected to the second node.
4. The apparatus of claim 3 , wherein the first inverter and the second inverter are supplied with a first power supply voltage and a second power supply voltage.
5. The apparatus of claim 4 , wherein the first power supply voltage is a positive power supply voltage, and the second power supply voltage is a negative power supply voltage.
6. The apparatus of claim 5 , wherein
when the pixel electrode circuit enters a pull-down mode,
the input voltage is equal to the first power supply voltage,
a first voltage at the third node is equal to the second power supply voltage, and
a second voltage at the second node is equal to the first power supply voltage,
wherein the first transistor and the second transistor are turned on, and an output voltage at the fifth node is pulled down to the ground.
7. The apparatus of claim 5 , wherein
when the pixel electrode circuit enters a floating mode,
the input voltage is equal to the second power supply voltage,
a first voltage at the third node is equal to the first power supply voltage, and
a second voltage at the second node is equal to the second power supply voltage,
wherein an output voltage at the fifth node follows the AC voltage through the second capacitor.
8. The apparatus of claim 7 , wherein when the output voltage at the fifth node is positive, the first transistor is turned on, and the second transistor is turned off, the fifth node is floating, and the output voltage at the fifth node follows the AC voltage through the second capacitor.
9. The apparatus of claim 7 , wherein when the output voltage at the fifth node is negative, the first transistor is turned off, the fifth node is floating, and the output voltage at the fifth node follows the AC voltage through the second capacitor.
10. An apparatus, comprising:
a pixel electrode circuit, comprising:
a first switch, controlled by a first control signal, the first switch comprising a first terminal electrically connected to an input voltage, and a second terminal electrically connected to a first node;
an inverter, coupled between the first node and a second node;
a first transistor, having a gate electrically connected to the second node, a first terminal connected to a fourth node, and a second terminal connected to a fifth node, the first transistor being a first-type transistor;
a second transistor, having a gate electrically connected to the first node, a first terminal being grounded, and a second terminal connected to the fourth node, the second transistor being a second-type transistor; and
a first capacitor and a second capacitor, wherein the first capacitor is coupled between the first node and a ground, and the fifth node is coupled to an alternating-current (AC) voltage through the second capacitor.
11. The apparatus of claim 10 , wherein the first transistor is a P-type transistor, and the second transistor is an N-type transistor.
12. The apparatus of claim 10 , wherein the inverter is supplied with a first power supply voltage and a second power supply voltage.
13. The apparatus of claim 12 , wherein the first power supply voltage is a positive power supply voltage, and the second power supply voltage is a negative power supply voltage.
14. The apparatus of claim 13 , wherein when the pixel electrode circuit enters a pull-down mode, the input voltage is equal to the first power supply voltage, and a first voltage at the first node is equal to the first power supply voltage, and a second voltage at the second node is equal to the second power supply voltage.
15. The apparatus of claim 14 , wherein the first transistor and the second transistor are turned on, and an output voltage at the fifth node is pulled down to the ground.
16. The apparatus of claim 13 , when the pixel electrode circuit enters a floating mode, the input voltage is equal to the second power supply voltage, and a first voltage at the first node is equal to the second power supply voltage, and a second voltage at the second node is equal to the first power supply voltage,
wherein an output voltage at the fifth node follows the AC voltage through the second capacitor.
17. The apparatus of claim 16 , wherein when the output voltage at the fifth node is positive, the first transistor is turned on, and the second transistor is turned off, the fifth node is floating, and the output voltage at the fifth node follows the AC voltage through the second capacitor.
18. The apparatus of claim 16 , wherein when the output voltage at the fifth node is negative, the first transistor is turned off, the fifth node is floating, and the output voltage at the fifth node follows the AC voltage through the second capacitor.