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US 2020/0007047 A1Published application
Variable voltage generator circuit, capacitor and method
AssigneeComet AG
InventorsThomas Fink, Ralf Negele
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AssigneeComet AG
InventorsThomas Fink, Ralf Negele
Estimating the term…
A variable voltage generator circuit is described for generating, from a substantially constant supply voltage VS, a variable high-voltage control voltage VC for a variable power capacitor (1) having a variable-permittivity dielectric. The control voltage generator circuit comprises a top-up circuit (10) for maintaining the voltage VCin on an input capacitor (12) at least at supply voltage VS, and a bidirectional DC-DC converter circuit (20) having a variable voltage conversion factor G controlled by control input signal (27). The bidirectional DC-DC converter (20) is arranged to convert voltage, at the voltage conversion factor G, between the input capacitor voltage VCin and the output voltage VC. When VC<G×VCin, the DC-DC converter circuit (20) uses charge stored in the input capacitor (12) to charge the capacitive load (1). When VC>G×VCin, the DC-DC converter circuit (20) uses charge stored in the load capacitance (1) to charge the input capacitor (12).
A variable voltage generator circuit for generating an output voltage, VC, which is variable in dependence on a voltage control input signal, for output to a substantially purely capacitive load, the circuit comprising:
A method of varying an output voltage VC applied to a substantially purely capacitive load, such that the net amount of electrical energy supplied to the load is substantially zero, the method comprising varying a voltage conversion factor G of a variable bidirectional DC-DC converter connected between an input capacitor and the load capacitance so as to convert a voltage VCin on the input capacitor to the output voltage VC on the load capacitance or vice versa, the method characterised by:
Dependencies are inferred from the claim text.