System and method for optically isolated current or voltage sensing
AssigneeToshiba America Electronic Components, Inc.
InventorJurgis Astrauskas
Life of this patent
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Abstract
A system and method for monitoring, testing or configuring electrical devices includes an input amplifier having an input connected to a device load line to generate an output linearly proportional to a voltage on the load line. An output of the input amplifier is connected to a photodiode in an optical path with a phototransistor. The phototransistor generates an output proportional to light generated by the photodiode, and this output is amplified and passed to an analog-to-digital converter. The converter generates a digital voltage level corresponding to the amplified output of the phototransistor. Digital temperature information is used to further enhance linearity of a generated digital voltage level. Multiple quantum well photodiodes further improve measurement linearity.
Claims13
An optically isolated sensing system comprising:
- an input connector configured to receive an input voltage;
- an output connector configured to output an output voltage linearly proportional to the received input voltage;
- a photodiode having an anode and a cathode;
- a ground connector configured to be connected to ground;
- a first operational amplifier including,
- a first operational amplifier output in electrical connection with the anode,
- a first operational amplifier inverting input in electrical connection with the cathode and the ground connector, and
- a first operational amplifier non-inverting input in electrical connection with the ground connector and the input connector;
- a phototransistor, having a collector and an emitter configured for electrical connection with an associated voltage source, the phototransistor secured proximate the photodiode in a light path with the photodiode;
- an isolated ground connector electrically isolated from the first ground connector;
- and
- a second operational amplifier electrically isolated from the first operational amplifier including,
- a second operational amplifier output in electrical connection with the output connector,
- a second operational amplifier non-inverting input in electrical connection with the collector and the second operational amplifier output, and
- a second operational amplifier inverting input in electrical connection with the isolated ground connector.
A system comprising:
- an input amplifier having an input connected to a load line so as to generate an output linearly proportional to a voltage on the load line;
- a photodiode connected to the output of the input amplifier;
- a phototransistor configured to receive light from the photodiode so as to generate an output proportional to the light generated by the photodiode;
- an output amplifier configured to amplify the output of the phototransistor;
- and
- an analog-to-digital converter configured to generate a digital voltage level corresponding to the amplified output of the phototransistor.
Dependencies are inferred from the claim text.