Temperature compensated closed-loop hall effect current transformer
AssigneeCrown Audio, Inc.
InventorGerald R. Stanley
Life of this patent
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Abstract
A closed loop Hall effect current transformer in which the Hall effect device has an input resistance which varies with its operating temperature. The Hall effect device is driven by a fixed voltage passing through a current limiting a resistor with variations in voltage across the resistor being indicative of the operating temperature of the device. Further, variations in the input resistance of the device caused by variations in its operating temperature is corrected for by mixing a correcting signal with the outputted signal from the device, said correcting signal being derived from a voltage signal taken across the resistor at the driving input of the device.
Claims14
In a closed loop Hall effect current transformer comprising a magnetic core having an air gap and being adapted to surround a conductor which produces a magnetic flux in said gap upon current flow through the conductor, a Hall effect device located in said core air gap, an operational amplifier connected to said device to receive a voltage signal from the device induced by said magnetic flux in said gap, a conductive winding about said core connected to said amplifier to receive a current produced by the amplifier in response to said voltage signal, said current serving to drive said voltage signal to zero, said device having an operating temperature coefficient, a regulating amplifier for applying a fixed voltage to said device, a resistor between said regulating amplifier and said device wherein the voltage across said resistor during operation of said device serves as a means for indicating the operating temperature of said device.
A closed-loop current transformer including:
- a core forming a gap and an opening for receiving a conductor, the conductor producing flux across the gap when current passes through the conductor;
- a winding extending around the core;
- a Hall effect device located in the gap and outputting a first signal proportional to the flux;
- a first amplifier receiving the first signal and outputting a second signal to the winding to reduce the first signal;
- a second amplifier outputting a fixed voltage to the device;
- and
- a resistor connected between the second amplifier and the device, the voltage across the resistor indicating the temperature of the device.
Dependencies are inferred from the claim text.