Micro-Electromechanical Switch Performance Enhancement

Abstract

In methods and circuits for using associated circuitry to enhance performance of a micro-electromechanical switch, one of the method embodiments is a contact conditioning process including applying a time-varying voltage to the control element of a closed switch. In another embodiment, a voltage profile applied to the control element of the switch can be tailored to improve the actuation speed or reliability of the switch. In another method embodiment, the performance of a switch may be evaluated by measuring a performance parameter, and corrective action initiated if the switch performance is determined to need improvement. An embodiment of a circuit for maintaining performance of a micro-electromechanical switch includes first and second signal line nodes, sensing circuitry coupled to the signal line nodes and adapted to sense a performance parameter value of the switch, and control circuitry operably coupled to at least one terminal of the switch.

1 . A method of actuating a micro-electromechanical switch, said method comprising applying a voltage profile including at least two nonzero voltage levels to a control element of the switch.  
   
   
       2 . The method of  claim 1 , wherein said actuating comprises closing the switch, and wherein the voltage profile includes: 
 a nonzero initial level; and    a subsequently-applied operating level having a voltage greater than the actuation voltage of the switch.    
   
   
       3 . The method of  claim 2 , wherein the initial level comprises a pre-bias level having a voltage less than the actuation voltage of the switch, and the operating level has a voltage greater than that of the initial level.  
   
   
       4 . The method of  claim 2 , wherein the initial level has a voltage at or slightly above the actuation voltage of the switch, and the operating level has a voltage greater than that of the initial level.  
   
   
       5 . The method of  claim 2 , wherein the initial level comprises a high-voltage pulse, and the operating level has a voltage less than that of the initial level.  
   
   
       6 . The method of  claim 5 , wherein a duration of the high-voltage pulse is shorter than the time needed for the switch to become physically closed in response to the pulse.  
   
   
       7 . The method of  claim 1 , wherein one or both of the nonzero voltage levels comprises a gradual voltage ramp.  
   
   
       8 . The method of  claim 1 , wherein a transition to one or more of the nonzero voltage levels comprises a voltage ramp.  
   
   
       9 . A method for maintaining performance of a micro-electromechanical switch comprising applying an electrical, thermal or magnetic stimuli during a time in which the switch is closed in order to condition contacts of the switch prior to another time in which the switch is open.  
   
   
       10 . A circuit for actuating a micro-electromechanical switch, said circuit comprising: 
 a control node operably coupled to a control element of the switch;    signal generation circuitry adapted for application of a voltage profile including at least two nonzero voltage levels to the control node; and    control circuitry operably coupled to the signal generation circuitry, wherein the control circuitry is adapted to initiate the application of a voltage profile in order to actuate the switch.    
   
   
       11 . The circuit of  claim 10 , wherein actuating the switch comprises closing the switch, and wherein the voltage profile includes: 
 a nonzero initial level; and    a subsequently-applied operating level having a voltage greater than the actuation voltage of the switch.    
   
   
       12 . The circuit of  claim 11 , further comprising sensing circuitry operably coupled to the control circuitry, wherein the sensing circuitry is adapted to determine the actuation voltage of the switch.  
   
   
       13 . The circuit of  claim 10 , further comprising voltage translation circuitry coupled between the signal generation circuitry and the control node, wherein the voltage translation circuitry is adapted to convert voltages output by the signal generation circuitry to relatively higher voltages needed to actuate the switch.  
   
   
       14 . The circuit of  claim 10 , further comprising electrostatic discharge protection circuitry coupled between the control element of the switch and an externally-accessible terminal of the switch.