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Patent Issued for Methods for Protecting Electronic Circuits Operating under High Stress Conditions

July 23, 2014



By a News Reporter-Staff News Editor at Journal of Engineering -- Analog Devices, Inc. (Norwood, MA) has been issued patent number 8772091, according to news reporting originating out of Alexandria, Virginia, by VerticalNews editors.

The patent's inventors are Salcedo, Javier A (North Billerica, MA); Whitney, David Hall (Westford, MA).

This patent was filed on August 14, 2013 and was published online on July 8, 2014.

From the background information supplied by the inventors, news correspondents obtained the following quote: "Embodiments of the invention relate to electronic systems, and more particularly, to protection circuits for integrated electronic systems.

"Certain electronic systems can be exposed to a transient electrical event, or an electrical signal of a relatively short duration having rapidly changing voltage and high power. Transient electrical events can include, for example, electro static discharge (ESD) events arising from the abrupt release of charge from an object or person to an electronic system. Transient electrical events can also include, for example, voltage spikes resulting from delivering a varying current to an inductive load, signals received by way of electromagnetic inductive coupling, or transient electrical events arising from starting a motor, such as a load dump transient electrical event resulting from starting an automotive engine.

"Transient electrical events can destroy an integrated circuit (IC) inside an electronic system due to overvoltage conditions and high levels of power dissipation over relatively small areas of the IC. High power dissipation can increase IC temperature, and can lead to numerous problems, such as gate oxide punch-through, junction damage, metal damage, and surface charge accumulation. Moreover, transient electrical events can induce latch-up (in other words, inadvertent creation of a low-impedance path), thereby disrupting the functioning of the IC and potentially causing permanent damage to the IC from self-heating in the latch-up current path.

"Certain integrated circuits, for instance, those used in automotive signal conditioning and sensing applications, are required to tolerate a relatively high level of over-voltage stress as well as false conditions at the input and/or output pins, such as short-to-battery condition. Thus, there is a need to provide an IC with protection from such transient electrical events. Furthermore, there is a need for a protection component providing an asymmetrical current versus voltage characteristics and that is able to safely sustain over-voltage stress and false conditions encountered in the relatively harsh automotive environment applications."

Supplementing the background information on this patent, VerticalNews reporters also obtained the inventors' summary information for this patent: "In one embodiment, an apparatus comprises a semiconductor substrate including a first p-well and a second p-well adjacent the first p-well. The first and second p-wells are separated by an n-type region. A first n-type active area is disposed over the first p-well and is electrically connected to a cathode of a first high reverse blocking voltage (HRBV) device. A first p-type active area is disposed over the second p-well and is electrically connected to an anode of the first HRBV device. The first n-type active area, the first p-well and the n-type region are configured to operate as an emitter, a base, and a collector of a NPN bipolar transistor, respectively, and the second p-well, the n-type region, and the first p-well are configured to operate as an emitter, a base, and a collector of a PNP bipolar transistor, respectively. The NPN bipolar transistor defines a forward trigger voltage of the first HRBV device and the PNP bipolar transistor defines a reverse breakdown voltage of the first HRBV device. The apparatus is configured to provide protection from a transient electrical event.

"In another embodiment, a method for providing protection from a transient electrical event includes providing a semiconductor substrate, forming a first p-well in the substrate, forming a second p-well in the substrate adjacent the first p-well such that the first and second p-wells are separated by an n-type region, forming a first n-type active area over the first p-well, and forming a first p-type active area over the second p-well. The first n-type active area is electrically connected to a cathode of a first high reverse blocking voltage (HRBV) device, and the first p-type active area is electrically connected to an anode of the first HRBV device. The first n-type active area, the first p-well and the n-type region are configured to operate as an emitter, a base, and a collector of a NPN bipolar transistor, respectively, and the second p-well, the n-type region, and the first p-well are configured to operate as an emitter, a base, and a collector of a PNP bipolar transistor, respectively. The NPN bipolar transistor defines a forward trigger voltage of the first HRBV device and the PNP bipolar transistor defines a reverse breakdown voltage of the first HRBV device.

"In another embodiment, an apparatus includes a semiconductor substrate having a first well and a second well adjacent the first well. The first and second wells have a doping of a first type and are separated by a doped region having a doping of a second type opposite the first. A first active area is over the first well, and has a doping of the second type. The first active area is electrically connected to a first terminal of a first high reverse blocking voltage (HRBV) device. A second active area is over the second well, and has a doping of the first type. The second active area is electrically connected to a second terminal of the first HRBV device. The first active area, the first well and the doped region are configured to operate as an emitter, a base, and a collector of a first bipolar transistor, respectively, and the second well, the doped region, and the first well are configured to operate as an emitter, a base, and a collector of a second bipolar transistor, respectively. The first bipolar transistor defines a forward trigger voltage of the first HRBV device and the second bipolar transistor defines a reverse breakdown voltage of the first HRBV device. The apparatus is configured to provide protection from a transient electrical event.

"In another embodiment, a method for providing protection from a transient electrical event includes providing a semiconductor substrate, forming a first well in the substrate, and forming a second well in the substrate adjacent the first well such that the first and second wells are separated by a doped region. The first and second wells have a doping of a first type, and the doped region has a doping of a second type opposite the first. The method further includes forming a first active area over the first well, the first active area having a doping of the second type and electrically connected to a first terminal of a first high reverse blocking voltage (HRBV) device. The method further includes forming a second active area over the second well, the second active area having a doping of the first type and electrically connected to a second terminal of the first HRBV device. The first active area, the first well and the doped region are configured to operate as an emitter, a base, and a collector of a first bipolar transistor, respectively, and the second well, the doped region, and the first well are configured to operate as an emitter, a base, and a collector of a second bipolar transistor, respectively. The first bipolar transistor defines a forward trigger voltage of the first HRBV device and the second bipolar transistor defines a reverse breakdown voltage of the first HRBV device."

For the URL and additional information on this patent, see: Salcedo, Javier A; Whitney, David Hall. Methods for Protecting Electronic Circuits Operating under High Stress Conditions. U.S. Patent Number 8772091, filed August 14, 2013, and published online on July 8, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8772091.PN.&OS=PN/8772091RS=PN/8772091

Keywords for this news article include: Automobiles, Electronics, Semiconductor, Transportation, Analog Devices Inc., Medical Device Companies.

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Source: Journal of Engineering


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