Adventive Ipbank

Advanced Analogic Technologies Incorporated

Applied Biophotonics Ltd.

Advanced Analogic Technologies (hong Kong) Limited

Skyworks Solutions (hong Kong) Limited

Adventive International Ltd.

Williams, Richard K.

Keng Hung Lin

Richard Kent Williams

Daniel Schell

Joseph P Leahy

Yu-Min Lin

A variety of footed and leadless semiconductor packages, with either exposed or isolated die pads, are described. Some of the packages have leads with highly coplanar feet that protrude from a plastic body, facilitating mounting the packages on printed circuit boards using wave-soldering techniques.

Universal surface-mount semiconductor package

A rigid-flex PCB includes an array of rigid PCB 'islands' interconnected by a flexible PCB formed into flexible connectors. The conductive and insulating layers of the flexible PCB extend into the rigid PCBs, giving the electrical connections to the rigid PCBs added resistance to breakage as the rigid-flex PCB is repeatedly stressed by bending and twisting forces. In addition, the durability of the rigid-flex PCB is enhanced by making the power and signal lines driving the rigid PCBs redundant so that a breakage of a line will not necessarily affect the operation of the rigid PCB to which it is attached. The rigid-flex PCB is particularly applicable to light pads used in phototherapy, wherein LEDs mounted on the rigid-PCBs are powered and controlled through the redundant lines in the flexible PCB.

Method of supplying electrical power from rigid printed circuit board to another rigid printed circuit board in rigid-flex printed circuit board array

The LEDs in a phototherapy LED pad are controlled so that the intensity of the light varies in accordance with a sinusoidal function, thereby eliminating the harmonics that are generated when the LEDs are pulsed digitally. This is accomplished analogically by using a sinusoidal wave to control the gate of a MOSFET connected in series with the LEDs or by using a digital-to-analog converter to control the gate of the MOSFET with a stair step function representative of the values of a sinusoidal function at predetermined intervals. Alternatively, pulse-width modulation is used to control the gate of the MOSFET in such a way that the average current through the LEDs simulates a sinusoidal function. In additional to using a simple sine wave function, the LED current may also be controlled in accordance with 'chords' containing multiple sine waves of different frequencies.

Phototherapy system with dynamic drive for light-emitting diodes

The LEDs in a phototherapy LED pad are controlled so that the intensity of the light varies in accordance with a sinusoidal function, thereby eliminating the harmonics that are generated when the LEDs are pulsed digitally, in accordance with a square-wave function. This is accomplished analogically by using a sinusoidal wave to control the gate of a MOSFET connected in series with the LEDs or by using a digital-to-analog converter to control the gate of the MOSFET with a stair step function representative of the values of a sinusoidal function at predetermined intervals. Alternatively, pulse-width modulation is used to control the gate of the MOSFET in such a way that the average current through the LEDs simulates a sinusoidal function. In additional to using a simple sine wave function, the LED current may also be controlled in accordance with 'chords' containing multiple sine waves of different frequencies.

Sinusoidal drive system and method for phototherapy

A method is disclosed of fabricating a power package which includes a heat tab extending from a die pad exposed on the underside of the package, which facilitates the removal of heat from the die to the PCB or other surface on which the package is mounted. The heat tab has a bottom surface coplanar with the flat bottom surface of the die pad and bottom surface of a lead. The lead includes a horizontal foot segment, a vertical columnar segment, and a horizontal cantilever segment facing the die pad. The heat tab may also have a foot. A die containing a power device is mounted on a top surface of the die pad and may be electrically connected to the lead using a bonding wire or clip. The die may be mounted on the die pad with an electrically conductive material, and the package may also include a lead that extends from the die pad and is thus electrically tied to the bottom of the die. The result is a package with a minimal footprint that is suitable for the technique known as 'wave soldering' that is used in relatively low-cost printed circuit board assembly factories.

Method of fabricating low-profile footed power package

3D bendable printed circuit board with redundant interconnections

A method is disclosed of fabricating a power package which includes a heat tab extending from a die pad exposed on the underside of the package, which facilitates the removal of heat from the die to the PCB or other surface on which the package is mounted. The heat tab has a bottom surface coplanar with the flat bottom surface of the die pad and bottom surface of a lead. The lead includes a horizontal foot segment, a vertical columnar segment, and a horizontal cantilever segment facing the die pad. The heat tab may also have a foot. A die containing a power device is mounted on a top surface of the die pad and may be electrically connected to the lead using a bonding wire or clip. The die may be mounted on the die pad with as electrically conductive material, and the package may also include a lead that extends from the die pad and is thus electrically tied to the bottom of the die. The result is a package with a minimal footprint that is suitable for the technique known as 'wave soldering' that is used in relatively low-cost printed circuit board assembly factories.

In a flexible LED pad for use in phototherapy treatment of humans or animals, the PCBs in the pad are securely linked together with electrical connectors and ribbon cables to prevent the connections from being broken as the flexible pad is bent or otherwise deformed during the treatment. In one embodiment, low-profile socket connectors are mounted to the PCBs and mate with plug connectors at the ends of the ribbon cables. For similar reasons, the LED pad may be connected to an LED control unit by means of an electrical connector (e.g. a USB socket) mounted to a PCB in the LED pad. The PCBs, on which the LEDs are mounted, are fitted into a downset in the flexible pad to prevent the LEDs from becoming misaligned with openings in the flexible pad.

Flexible LED light pad for phototherapy

A power package includes a heat tab extending from a die pad exposed on the underside of the package, which facilitates the removal of heat from the die to the PCB or other surface on which the package is mounted. The heat tab has a bottom surface coplanar with the flat bottom surface of the die pad and bottom surface of a lead. The lead includes a horizontal foot segment, a vertical columnar segment, and a horizontal cantilever segment facing the die pad. The heat tab may also have a foot. A die containing a power device is mounted on a top surface of the die pad and may be electrically connected to the lead using a bonding wire or clip. The die may be mounted on the die pad with an electrically conductive material, and the package may also include a lead that extends from the die pad and is thus electrically tied to the bottom of the die. The result is a package with a minimal footprint that is suitable for the technique known as 'wave soldering' that is used in relatively low-cost printed circuit board assembly factories. Methods of fabricating the package are disclosed.

Low-profile footed power package

In the fabrication of semiconductor packages, a leadframe is formed by masking and etching a metal sheet from both sides, and a plastic block is formed over a plurality of dice attached to die pads in the leadframe. A laser beam is used to form individual plastic capsules for each package, and a second laser beam is used to singulate the packages by severing the metal conductors, tie bars and rails between the packages. A wide variety of different types of packages, from gull-wing footed packages to leadless packages, with either exposed or isolated die pads, may be fabricated merely by varying the patterns of the openings in the mask layers and the width of the plastic trenches created by the first laser beam.

In a bump-on-leadframe semiconductor package a metal bump formed on a integrated circuit die is used to facilitate the transfer of heat generated in a semiconductor substrate to a metal heat slug and then to an external mounting surface. A structure including arrays of thermal vias may be used to transfer the heat from the semiconductor substrate to the metal bump.

Integrated circuit die with low thermal resistance

To avoid shorts between adjacent die pads in mounting a multi-die semiconductor package to a printed circuit board (PCB), one of the die pads is embedded in the polymer capsule, while the other die pad is exposed at the bottom of the package to provide a thermal escape path to the PCB. This arrangement is particularly useful when one of the dice in a multi-die package generates more heat than another die in the package. A process for fabricating the package includes a partial etch that defines the bottom surface of the embedded die pad and may include a through-etch that leaves one or more of the contacts or leads integrally connected to the embedded die pad.

Process for fabricating multi-die semiconductor package with one or more embedded die pads

To avoid shorts between adjacent die pads in mounting a multi-die semiconductor package to a printed circuit board (PCB), one of the die pads is embedded in the polymer capsule, while the other die pad is exposed at the bottom of the package to provide a thermal escape path to the PCB. This arrangement is particularly useful when one of the dice in a multi-die package generates more heat than another die in the package.

Growing community of inventors

Chupei, Taiwan

Keng Hung Lin