Variable impedance circuit
AssigneeWestinghouse Electric Corp.
InventorsKlaus D. May, Dana L. Eckstein
Life of this patent
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Abstract
The variable impedance circuit comprising the invention provides a circuit having an impedance which varies in response to an input signal. The invention utilizes a control circuit which samples the load current and compares it to the demand signal to generate a control signal. The control signal is coupled to a load driver circuit to cause the required current to flow through this circuit. The load driver circuit and one or more substantially identical load circuits are series coupled to form a variable impedance circuit having the desired voltage and current capability.
Claims9
A variable impedance circuit for loading a voltage source to a desired current, the magnitude of said desired current being specified by a demand signal, comprising in combination:
- (a) a control circuit for sensing the current loading of said voltage source and for comparing said sensed current to said demand signal to generate a control signal;
- said control circuit also including an optical isolator providing electrical isolation between said demand signal and the remainder of said variable impedance circuit
- (b) a load driver circuit responsive to said control signal to adjust the current through said load driver circuit to the value specified by said demand signal;
- (c) at least one load circuit series coupled with said load driver circuit, said at least one load circuit being responsive to the voltage drop across the series combination of said load driver circuit and said at least one additional load circuit to provide a current through the series combination of said load driver circuit and said at least one load circuit substantially equal to the current specified by said current demand signal, and a substantially equal voltage drop across said load driver circuit and each of said at least one additional load circuits.
Dependencies are inferred from the claim text.