Alpha & Omega Semiconductor Patent Grants

Dual trench-gate IGBT structure

Granted: July 18, 2017
Patent Number: 9711631
An IGBT device includes a substrate having a bottom semiconductor layer of a first conductivity type and an upper semiconductor layer of a second conductivity type, at least one first gate formed in a corresponding first trench disposed over the substrate, and a second gate formed in a second trench disposed over the bottom semiconductor layer. The first and second trenches are provided with gate insulators on each side of the trenches and filled with polysilicon. The second trench…

Molded intelligent power module

Granted: July 11, 2017
Patent Number: 9704789
An intelligent power module (IPM) has a first, second, third and fourth die paddles, a first, second, third, fourth, fifth and sixth transistors, a tie bar, a low voltage IC, a high voltage IC, a first, second and third boost diodes, a plurality of leads and a molding encapsulation. The first transistor is attached to the first die paddle. The second transistor is attached to the second die paddle. The third transistor is attached to the third die paddle. The fourth, fifth and sixth…

Power trench MOSFET with improved unclamped inductive switching (UIS) performance and preparation method thereof

Granted: July 11, 2017
Patent Number: 9704948
A trench type power semiconductor device with improved breakdown voltage and UIS performance and a method for preparation the device are disclosed. The trench type power semiconductor device includes a first contact hole formed in a mesa in the active area and a second contact hole formed in a mesa in an active to termination intermediate area, where the first contact hole is deeper and wider than the second contact hole.

Nanotube semiconductor devices

Granted: July 11, 2017
Patent Number: 9704955
Semiconductor devices are formed using a thin epitaxial layer (nanotube) formed on sidewalls of dielectric-filled trenches. In one embodiment, a method for forming a semiconductor device includes forming a first epitaxial layer on sidewalls of trenches and forming second epitaxial layer on the first epitaxial layer where charges in the doped regions along the sidewalls of the first and second trenches achieve charge balance in operation. In another embodiment, the semiconductor device…

Fault tolerant power supply incorporating intelligent gate driver-switch circuit to provide uninterrupted power

Granted: July 11, 2017
Patent Number: 9705395
A fault tolerant power supply system includes at least one load switch configured to connect an input voltage to an output node of the load switch when the load switch is turned on and at least one power channel coupled to the load switch to receive the input voltage. The power channel is configured as a buck converter and includes at least a high-side power switch and a low-side power switch. The fault tolerant power supply system is configured to measure a current flowing through the…

Magnetic stripe data transmission system and method for reliable data transmission and low power consumption

Granted: July 4, 2017
Patent Number: 9697450
A magnetic stripe data transmission (MST) driver and a method for driving the MST are disclosed. The MST driver is configured to transmit magnetic strip data comprising of streams of pulses. The MST driver comprises a pair of high side switches and a pair of low side switches. The pair of high side switches comprises a first switch and a second switch. The pair of low side switches comprises a third switch and a fourth switch. The first, second, third and fourth switches are arranged in…

Lateral PNP bipolar transistor with narrow trench emitter

Granted: July 4, 2017
Patent Number: 9698237
A lateral bipolar transistor includes trench emitter and trench collector regions to form ultra-narrow emitter regions, thereby improving emitter efficiency. The same trench process is used to form the emitter/collector trenches as well as the trench isolation structures so that no additional processing steps are needed to form the trench emitter and collector. In embodiments of the present invention, the trench emitter and trench collector regions may be formed using ion implantation…

Self-aligned contact for trench power MOSFET

Granted: June 27, 2017
Patent Number: 9691863
Embodiments of the present disclosure provide a self-aligned contact for a trench power MOSFET device. The device has a layer of nitride provided over the conductive material in the gate trenches and over portions of mesas between every two adjacent contact structures. Alternatively, the device has an oxide layer over the conductive material in the gate trenches and over portions of mesas between every two adjacent contact structures. It is emphasized that this abstract is provided to…

Method and circuit for detecting short circuit in an asynchronous DC-DC boost converter

Granted: June 20, 2017
Patent Number: 9684326
A simple, cost-effective and efficient short circuit protection with simple routing of the ground on the PCB is achieved in an asynchronous DC-DC boost converter wherein a voltage sensing controller selectively isolates an input power supply to a load in the event of a short circuit. The controller alleviates need for additional components by utilizing the circuit for under voltage lockout protection and the circuit for overvoltage protection to generate signals for detecting short…

Embedded package and method thereof

Granted: June 20, 2017
Patent Number: 9685430
A method of manufacturing an embedded package comprises attaching a plurality of chips on a pre-mold lead frame; forming a first lamination layer on the plurality of chips, the pre-mold lead frame and a plurality of pins; forming a first plurality of vias and a second plurality of vias through the first lamination layer; forming a respective conductive plug of a plurality of conductive plugs by depositing a respective conductive material in each of the first plurality of vias and each of…

Integrated snubber in a single poly MOSFET

Granted: June 20, 2017
Patent Number: 9685435
Aspects of the present disclosure describe MOSFET devices that have snubber circuits. The snubber circuits comprise one or more resistors with a dynamically controllable resistance that is controlled by changes to a gate and/or drain potentials of the one or more MOSFET structures during switching events.

Compact guard ring structure for CMOS integrated circuits

Granted: June 20, 2017
Patent Number: 9685443
An integrated circuit includes an active device formed in a semiconductor layer of a first conductivity type, a first guard ring of the first conductivity type formed in the semiconductor layer surrounding at least part of the active device; a second guard ring of the second conductivity type formed in the semiconductor layer surrounding the first guard ring and the active device and including comprising alternating first well regions of the first conductivity type and the second well…

Diode structures with controlled injection efficiency for fast switching

Granted: June 20, 2017
Patent Number: 9685523
This invention discloses a semiconductor device disposed in a semiconductor substrate. The semiconductor device includes a first semiconductor layer of a first conductivity type on a first major surface. The semiconductor device further includes a second semiconductor layer of a second conductivity type on a second major surface opposite the first major surface. The semiconductor device further includes an injection efficiency controlling buffer layer of a first conductivity type…

Circuit and method for evaluation overload condition in flyback converter

Granted: June 20, 2017
Patent Number: 9685874
A circuit and a method for evaluating a load condition in a flyback converter are disclosed. A first current source is used for providing a preset current ISUM equal to a sum of the off current value IOFF and the blanking current value ILEB to charge a first capacitor, and a second current source is used for providing a reference current IREF to charge a second capacitor. A comparator receives a voltage applied on the first capacitor at its positive input end and a voltage applied on the…

Method for monitoring epitaxial growth geometry shift

Granted: June 13, 2017
Patent Number: 9679822
A method of monitoring an epitaxial growth geometry shift is disclosed. First, second and third trenches are formed on a semiconductor wafer. An epitaxial layer is grown. The epitaxial layer covers the first trenches and the second trenches but not the third trenches. First and second recesses on a top surface of the epitaxial layer are formed. First and second openings aligned with the first and the second recesses and a third openings aligned with the third trenches are formed in a…

Semiconductor package with small gate clip and assembly method

Granted: June 13, 2017
Patent Number: 9679833
A method of manufacturing a semiconductor package having a small gate clip is disclosed. A first and second semiconductor chips, each of which includes a source electrode and a gate electrode at a top surface, are attached on two adjacent lead frame units of a lead frame such that the lead frame unit with the first chip formed thereon is rotated 180 degrees in relation to the other lead frame unit with the second semiconductor chip formed thereon. A first and second clip sets are mounted…

Dual oxide trench gate power MOSFET using oxide filled trench

Granted: June 6, 2017
Patent Number: 9673289
A power MOSFET device including a semiconductor layer, an active trench formed in the semiconductor layer and housing a dual oxide thickness trench gate structure where a bottom of the trench gate is isolated from a bottom of the active trench by a liner oxide layer having a first thickness, and a termination trench formed in the semiconductor layer apart from the active trench and housing a dual oxide thickness trench gate structure where a bottom of the trench gate is isolated from a…

Methods and devices for detecting the input voltage and discharging the residuevoltage

Granted: May 30, 2017
Patent Number: 9664714
The present invention relates to power conversion systems, specifically, it relates to a device for detecting the DC voltage rectified from the AC power supply voltage in an AC-DC converter, primarily used to determine whether the DC input voltage is under a brown-out level and to monitor whether the AC power supply is removed and to discharge the residue DC voltage generated in a high frequency filter capacitor, which is used to filter high frequency noise signals of the AC power…

Dual-gate trench IGBT with buried floating P-type shield

Granted: May 30, 2017
Patent Number: 9666666
A method of manufacturing an insulated gate bipolar transistor (IGBT) device comprising 1) preparing a semiconductor substrate with an epitaxial layer of a first conductivity type supported on the semiconductor substrate of a second conductivity type; 2) applying a gate trench mask to open a first trench and second trench followed by forming a gate insulation layer to pad the trench and filling the trench with a polysilicon layer to form the first trench gate and the second trench gate;…

Semiconductor device with thick bottom metal and preparation method thereof

Granted: May 16, 2017
Patent Number: 9653383
A semiconductor device with thick bottom metal comprises a semiconductor chip covered with a top plastic package layer at its front surface and a back metal layer at its back surface, the top plastic package layer surrounds sidewalls of the metal bumps with a top surface of the metal bumps exposing from the top plastic package layer, a die paddle for the semiconductor chip to mount thereon and a plastic package body.