Charge pump systems, devices, and methods
The present subject matter relates to charge pump devices, systems, and methods in which a plurality of series-connected charge-pump stages are connected between a supply voltage node and a primary circuit node, and a discharge circuit is connected to the plurality of charge-pump stages, wherein the discharge circuit is configured to selectively remove charge from the primary circuit node.
1. A micro-electro-mechanical systems (MEMS) array comprising:
a plurality of charge pumps, each of the plurality of charge pumps comprising a plurality of series-connected charge-pump stages connected between a supply voltage node and a primary circuit node;
a plurality of MEMS devices, each of the plurality of MEMS devices connected to one of the plurality of charge pumps and comprising:
at least one fixed electrode; and
a movable beam including at least one movable electrode that is spaced apart from the at least one fixed electrode and is movable with respect to the at least one fixed electrode;
wherein the primary circuit node of the one of the plurality of charge pumps is connected to one of the at least one movable electrode or the at least one fixed electrode; and
a controller in communication with each of the plurality of charge pumps, wherein the controller is configured to control the plurality of charge pumps to drive a corresponding combination of the plurality of MEMS devices that corresponds to a desired total array behavior of the plurality of MEMS devices.
2. The micro-electro-mechanical systems (MEMS) array of claim 1 , wherein each of the charge-pump stages comprises a silicon-on-insulator (SOI) device.
3. The micro-electro-mechanical systems (MEMS) array of claim 1 , wherein each of the plurality of charge pumps comprises a discharge circuit connected to the plurality of charge-pump stages, wherein the discharge circuit is configured to selectively remove charge from the primary circuit node.
4. The micro-electro-mechanical systems (MEMS) array of claim 3 , wherein the discharge circuit comprises a plurality of transistors arranged in a cascaded array between the primary circuit node and a reference, wherein each of the plurality of transistors is connected to one of the plurality of charge pump stages.
5. The micro-electro-mechanical systems (MEMS) array of claim 4 , wherein the discharge circuit comprises a diode connected between a gate and a drain of each of the plurality of transistors.
6. The micro-electro-mechanical systems (MEMS) array of claim 1 , comprising a voltage measurement device configured to measure a present charge state at the primary circuit node;
wherein the voltage measurement device is connected in communication with one of the plurality of charge-pump stages, and
wherein the voltage measurement device is configured to extrapolate the present charge state at the primary circuit node from a voltage measurement taken at the one of the plurality of charge-pump stages.
7. A method for operating a micro-electro-mechanical systems (MEMS) array comprising a plurality of MEMS devices, each of the plurality of MEMS devices comprising at least one fixed electrode and a movable beam including at least one movable electrode that is spaced apart from the at least one fixed electrode and is movable with respect to the at least one fixed electrode, the method comprising:
connecting a plurality of charge pumps to the plurality of MEMS devices, each of the plurality of charge pumps comprising a supply voltage node, a primary circuit node, and a plurality of series-connected charge-pump stages connected between the supply voltage node and the primary circuit node, wherein the primary circuit node of each of the plurality of charge pumps is connected to one of the at least one movable electrode or the at least one fixed electrode of one of the plurality of MEMS devices; and
selectively operating the plurality of charge pumps to drive a corresponding combination of the plurality of MEMS devices that corresponds to a desired total array behavior of the plurality of MEMS devices.
8. The method of claim 7 , wherein selectively operating the plurality of charge pumps comprises driving charge between the series-connected charge-pump stages in response to a control input from a clock driver circuit.
9. The method of claim 7 , further comprising selectively removing charge from the primary circuit node through a discharge circuit connected to the plurality of charge-pump stages.
10. The method of claim 9 , wherein selectively removing charge comprises controlling a diode connected between a gate and a drain of each of the plurality of transistors.
11. The method of claim 7 , further comprising measuring a present charge state at the primary circuit node by extrapolating the present charge state from a voltage measurement taken at one of the plurality of charge-pump stages.
12. The method of claim 11 , wherein selectively operating the plurality of charge pumps comprises driving charge between the stages of the plurality of series-connected charge-pump stages if the present charge state is less than a desired charge state.