Electrically-isolated high-voltage sensor with low power dissipation

Abstract

Novel electrically-isolated high-voltage sensors are provided which have low power dissipation. The sensors are formed of a circuit comprising first and second portions separated by an electrical isolation boundary with the first portion used for high-voltage, and the second portion for low-voltage. While they are decoupled electrically, they are coupled both optically and magnetically. The first portion comprises an LED which generates an optical signal corresponding to a high-voltage signal across the electrical-isolation boundary. The second portion comprises a photodiode which receives the optical signal emitted from the LED and outputs a corresponding low-voltage electrical signal. A temperature-compensating LED biasing sub-circuit may span both portions and include a temperature sensor, a coupled inductor magnetically coupling the electrical isolation boundary, and a rectifier and filter, to provide a bias to the LED which biases the LED to operate in a substantially-linear manner irrespective of the ambient temperature.

Dependencies are inferred from the claim text.