Reinforced isolation for current sensor with magnetic field transducer

摘要

A current sensor packaged in an integrated circuit package to include a magnetic field sensing circuit, a current conductor and an insulator that meets the safety isolation requirements for reinforced insulation under the UL 60950-1 Standard is presented. The insulator is provided as an insulation structure having at least two layers of thin sheet material. The insulation structure is dimensioned so that plastic material forming a molded plastic body of the package provides a reinforced insulation. According to one embodiment, the insulation structure has two layers of insulating tape. Each insulating tape layer includes a polyimide film and adhesive. The insulation structure and the molded plastic body can be constructed to achieve at least a 500 VRMS working voltage rating.

主权项

1. A current sensor comprising:
a lead frame having a first portion comprising current leads connected to form a current conductor to carry a primary current and a second portion comprising signal leads; a die, coupled to the second portion by an interconnect, comprising a magnetic field sensing circuit to sense a magnetic field associated with the primary current and produce an output based on the sensed magnetic field at one of the signal leads; an insulation structure disposed between the current conductor and the die, comprising a first insulation layer and a second insulation layer; plastic material surrounding the die, the interconnect and at least a portion of the lead frame to form a molded package body; and wherein the insulation structure is dimensioned so that the plastic material provides a reinforced insulation; and wherein the insulation structure covers at least a portion of the current conductor and extends beyond a periphery of the current conductor.