Volterra Semiconductor Corporation

Yang Lu

Marco A Zuniga

Jun Ruan

Amit Paul

Badredin Fatemizadeh

Jayasimha Prasad

Chiteh Chiang

Budong You

Hamza Yilmaz

Craig Cassella

John Xia

William Numann

A voltage regulator includes a high-side device, a low-side device, and a controller. The high-side device includes first and second transistors each coupled between an input terminal and an intermediate terminal, where the first transistor has a higher breakdown voltage than the second transistor. The low-side device is coupled between the intermediate terminal and a ground terminal. The controller is configured to drive the high-side and low-side devices to (a) alternately couple the intermediate terminal to the input terminal and the ground terminal and (b) cause the first transistor to control a voltage across the second transistor during switching transitions of the second transistor.

Voltage regulators with multiple transistors

The subject matter of this document can be embodied in a method that includes a voltage regulator having an input terminal and an output terminal. The voltage regulator includes a high-side transistor between the input terminal and an intermediate terminal, and a low-side transistor between the intermediate terminal and ground. The voltage regulator includes a low-side driver circuit including a capacitor and an inverter. The output of the inverter is connected to the gate of the low-side transistor. The voltage regulator also includes a controller that drives the high-side and low-side transistors to alternately couple the intermediate terminal to the input terminal and ground. The controller is configured to drive the low-side transistor by controlling the inverter. The voltage regulator further includes a switch coupled to the low-side driver circuit. The switch is configured to block charge leakage out of the capacitor during an off state of the low-side transistor.

Voltage regulators with kickback protection

The present application features a transistor that includes an n-well region implanted into a surface of a substrate, a gate region, and a source region, and a drain region. The source region is on a first side of the gate region and includes a p-body region in the n-well region. An n+ region and a p+ region are implanted in the p-body region such that the p+ region is below the n+ region. The drain region is on a second side of the gate region and includes an n+ region.

Transistor with buried P+ and source contact

A voltage regulator has an input terminal and a ground terminal. The voltage regulator includes a high-side device, a low side device, and a controller. The high-side device is coupled between the input terminal and an intermediate terminal. The high-side device includes first and second transistors each coupled between the input terminal and the intermediate terminal, such that the first transistor controls a drain-source switching voltage of the second transistor. The low-side device is coupled between the intermediate terminal and the ground terminal. The controller drives the high-side and low-side devices to alternately couple the intermediate terminal to the input terminal and the ground terminal.

A transistor includes a substrate, a well formed in the substrate, a drain including a first impurity region implanted in the well, a source including a second impurity region implanted in the well and spaced apart from the first impurity region, a channel for current flow from the drain to the source, and a gate to control a depletion region between the source and the drain. The channel has an intrinsic breakdown voltage, and the well, drain and source are configured to provide an extrinsic breakdown voltage lower than the intrinsic breakdown voltage and such that breakdown occurs in a breakdown region in the well located outside the channel and adjacent the drain or the source.

Method of fabricating power transistor with protected channel

This document describes systems and techniques related to voltage regulators. The subject matter of this document can be embodied in a method that includes measuring an output current of a switching regulator. The switching regulator includes a high-side transistor and a low side-transistor wherein the high-side transistor and the low-side transistor are driven using a first gate voltage and a second, different gate voltage, respectively. The method also includes adjusting a direct-current (DC) voltage source of the switching regulator such that the first gate voltage is adjusted in accordance with the measured output current.

Voltage regulators with load-dependent bias

Described here are transistors and fabrication methods thereof. In one implementation, a transistor includes an n-well region implanted into a surface of a substrate, and a trench in the n-well region. The trench extends from the surface to a first depth. The trench includes a gate of conductive material in the trench, and dielectric material filling a volume of the trench not filled by the conductive material. The transistor also includes a p-type material in a first region extending from a second depth to a third depth, the second depth and the third depth being greater than the first depth. The transistor further includes a source region and a drain region.

Vertical gate LDMOS device

A method of fabricating a vertical gate region in LDMOS transistor includes depositing a first masking layer on an n-well region implanted on a substrate, patterning the first masking layer to define an area, depositing a second masking layer over the area, etching through the second masking layer in a first portion of the area to expose the n-well region, and etching the exposed n-well region to form a first trench. The first trench, extending from a surface of the n-well region to a first depth, is filled with an oxide. The second masking layer is etched through in a second portion of the area to expose the n-well region. A second trench is formed in the n-well, the second trench extending from the surface to a second depth, less than the first depth. An asymmetric vertical gate is formed by filling the second trench with a conductive material.

The present application features methods of fabricating a gate region in a vertical laterally diffused metal oxide semiconductor (LDMOS) transistor. In one aspect, a method includes depositing a masking layer on an n-well region implanted on a substrate, patterning the masking layer to define an area, and forming a first trench in the area such that a length of the first trench extends from a surface of the n-well region to a first depth in the n-well region. The method also includes filling the first trench by a conductive material and depositing a layer of oxide over the area. The method further includes etching out at least a portion of the oxide layer to expose a portion of the conductive material, removing the conductive material from the exposed portion to form a second trench, and filling the second trench with an oxide to form an asymmetric gate of the transistor.

A transistor includes a substrate, a well formed in the substrate, a drain including a first impurity region implanted in the well, a source including a second impurity region implanted in the well and spaced apart from the first impurity region, a channel for current flow from the drain to the source, and a gate to control a depletion region between the source and the drain The channel has an intrinsic breakdown voltage, and the well, drain and source are configured to provide an extrinsic breakdown voltage lower than the intrinsic breakdown voltage and such that breakdown occurs in a breakdown region in the well located outside the channel and adjacent the drain or the source.

Power transistor with protected channel

An LDMOS transistor includes a gate including a conductive material over an insulator material, a source including a first impurity region and a second impurity region, a third impurity region, and a drain including a fourth impurity region and a fifth impurity region. The first impurity region is of a first type, and the second impurity region is of an opposite second type. The third impurity region extends from the source region under the gate and is of the first type. The fourth impurity region is of the second type, the fifth impurity region is of the second type, and the fourth impurity region impinges the third impurity region.

Growing community of inventors

Fremont, CA, United States of America

Yang Lu