Method and apparatus for driver circuit in a MEMS device

• US 7,203,111 B2
• Filed: 02/08/2005
• Issued: 04/10/2007
• Est. Priority Date: 02/08/2005
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Martin, Eric, Wang, Stanley J., Enciso, Edward
• Primary Examiner(s): NGUYEN, VAN THU T
• Application Number:
  US11/054,075
• Publication Number:
  US 20060176746A1
• Time in Patent Office: 791 Days
• Field of Search: 365/203.O, 365/230.06 X, 365/244, 365/203, 365/230.06
• US Class Current: 365/203
• CPC Class Codes: G11C 7/12 Bit line control circuits, e.g. drivers, boosters, pull-up circuits, pull-down circuits, precharging circuits, equalising circuits, for bit lines

Abstract

An embodiment includes a first semiconductor element coupled between a precharge signal and a node, the first semiconductor element to allow current to flow from the precharge signal to the node when a positive voltage is present on the precharge signal, and a switching device coupled between the node and a voltage signal, the switching device to allow current flow between the node and the voltage signal when an enable signal is asserted.

Claims

1. An apparatus, comprising:

a MEMS device;

a first semiconductor element coupled between a precharge signal and a node coupled to the MEMS device, the first semiconductor element to allow current to flow from the precharge signal to the node when a positive voltage is present on the precharge signal; and

a switching device coupled between the node and a voltage signal, the switching device to allow current flow between the node and the voltage signal to partially discharge an appropriate amount of charge to set a desired voltage level between the voltage signal and the precharge signal when an enable signal is asserted.

2. The apparatus of claim 1, the first semiconductor element comprising a diode.

3. The apparatus of claim 2, the switching device comprising a transistor including a gate, the enable signal coupled to the gate.

4. The apparatus of claim 3, the diode including an anode and a cathode, the anode coupled to the precharge signal and the cathode coupled to the node.

5. The apparatus of claim 1, further comprising a capacitor coupled between the node and ground.

6. The apparatus of claim 5, the precharge signal comprising a row precharge signal and the voltage signal comprising a column voltage signal.

7. A method, comprising:

applying a row precharge voltage to a node coupled to a MEMS device;

setting a column voltage; and

asserting a row enable signal to a switching device coupled between the node and the column voltage to cause the node voltage to approximately match the column voltage to partially discharge an appropriate amount of charge to set a desired voltage level between the column voltage and the row precharge voltage.

8. The method of claim 7, wherein applying a row precharge voltage to a node includes applying a row precharge voltage to an anode of a diode.

9. The method of claim 8, wherein applying a row precharge voltage to a node further includes coupling a cathode of the diode to the node.

10. The method of claim 9, wherein applying a row precharge voltage to a node further includes applying a row precharge voltage to the MEMS device coupled to the node.

11. An apparatus, comprising:

means for allowing current to flow from a precharge signal to a node coupled to a MEMs device when a positive voltage is present on the precharge signal; and

means for allowing current to flow between the node and a voltage signal when an enable signal is asserted to partially discharge an appropriate amount of charge to set a desired voltage level between the voltage signal and the precharge signal.

12. The apparatus of claim 11, further comprising means for holding charge coupled between the node and ground.

13. The apparatus of claim 11, the precharge signal comprising a row precharge signal and the voltage signal comprising a column voltage signal.

14. An apparatus, comprising:

one or more semiconductor devices adapted to provide an input node signal to a MEMS device, as follows;

applying a row precharge voltage to an input node;

setting a column voltage; and

asserting a row enable signal to a switching device coupled between the input node and the column voltage to cause the input node voltage to partially discharge an appropriate amount of charge to set a desired voltage level between the column voltage and the row precharge voltage.

15. The apparatus of claim 14, wherein applying a row precharge voltage to an input node includes applying a row precharge voltage to an anode of a diode.

16. The apparatus of claim 15, wherein applying a row precharge voltage to an input node further includes coupling a cathode of the diode to the input node.

17. The apparatus of claim 16, wherein applying a row precharge voltage to an input node further includes applying a row precharge voltage to the MEMS device coupled to the input node.