Motorola Corporation

Paul G Alonas

Vernon P O'Neil, Ii

David M Gilbert

David M Heminger

Jang-Hun (James) Yeh

Austin Vincent Harton

Joseph H Slaughter, Iii

Niraj Kohli

William M Coppock

A triac (100) utilizes an FET (107) to inhibit firing of a transistor (112) that forms a portion of the SCR of the triac (100). A DMOS transistor (106) is used to supply a substantially constant bias current to the transistor (107) in order to facilitate rapid turn-on of the transistor (107) around the zero-crossing of the voltage applied to the triac (100).

Zero-crossing triac and method

An opto-isolator (10) increases optical efficiency by using holographic elements (22,24,26) to direct a beam of light (34) through an optical waveguide (20). An opto-electronic transmitter (12) and receiver (16) are connected to the waveguide to be in alignment with the beam of light reflected by the holographic elements. The transmitter and receiver are disposed on separate leadframe portions (14,18), and the opto-isolator is surrounded by a package (32).

Holographic optical isolator utilizing opto-electronic transmitter and

Improved resistance to electrical instability of opto-isolators subjected to large stand-off voltages is obtained by coating the semiconductor light sensing element with a high resistivity layer of amorphous silicon while leaving most of the surface PN junction perimeter and nearby regions free of metal. The amorphous silicon prevents mobile ions in the encapsulation, which are driven to the detector surface by the stand-off voltage, from inverting or modulating the conductivity of the detector surface and causing instability. The amorphous silicon also makes it possible to leave most of the light sensitive PN junctions and nearby regions free of metal, thereby simplifying design of complex IC detector chips and increasing sensitivity.

Complex opto-isolator with improved stand-off voltage stability

A monolithic light-activated line-operable zero-crossing switch and method of making the same. The device comprises anti-parallel thyristors, each of whose gates is shunted by a field effect transistor. Each device may also be shunted by a resistor to reduce the overall sensitivity. The method of making the device contemplates surrounding the field effect transistor gate electrode and an internal shunt electrode by the primary metallization which forms the contact to the two main terminals of the device.

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Scottsdale, AZ, United States of America

Paul G Alonas