Patent ID: 6081075
Filing Date: 2000-06-27
Classification: H05B,Y02B,Y10S

Abstract:
A switching circuit for a DC to AC inverter utilized for driving a substantially capacitive load, the switching circuit comprising:first and second input terminals connected to a DC voltage and a DC reference, respectively;first and second output terminals for connection to said capacitive load;a control circuit exhibiting first, second, third, and fourth states of operation;first switching means responsive to said control circuit for connecting said first input terminal to said first output terminal during said first state of operation;second switching means responsive to said control circuit for connecting said first input terminal to said second output terminal during said third state of operation;first current conduction means for connecting said first output terminal to said DC reference, said first current conduction means presenting an open circuit in which current flow therethrough is substantially zero during said first state of operation, said first current conduction means being operative for conducting a substantially constant current during said second state of operation while the voltage at said first output terminal is substantially greater than said DC reference, said constant current dropping to a relatively small value when the voltage at said first output terminal is substantially equal to said DC reference, said first current conduction means being further operative for conducting a substantially constant current from said first output terminal during said third state of operation while the voltage at said first output terminal is substantially greater than said DC reference, said constant current dropping to a relatively small value as the voltage at said first output terminal is substantially equal to said DC reference, said first current conduction means being further operative for maintaing the voltage at said first output terminal substantially equal to said DC reference during said fourth state of operation;second current conduction means for connecting said second output terminal to said DC reference, said second current conduction means being operative for conducting a substantially constant current from said second output terminal during said first state of operation while the voltage at said second output terminal is substantially greater than said DC reference, said constant current dropping to a relatively small value when the voltage at said second output terminal is substantially equal to said DC reference, said second current conduction means being further operative for maintaining the voltage at said second output terminal substantially equal to said DC reference voltage during said second state of operation, said second current conduction means presenting an open circuit in which the current flow therethrough is substantially zero during said third state of operation, said second current conduction means being further operative for conducting a substantially constant current from said second output terminal during said fourth state of operation while the voltage at said second output terminal is substantially greater than said DC reference, said constant current dropping to a relatively small value when the voltage at said second output terminal is substantially equal to said DC reference.