Electricity: conductors and insulators – Boxes and housings – Hermetic sealed envelope type
Reexamination Certificate
2001-11-14
2004-03-30
Ngo, Hung V. (Department: 2831)
Electricity: conductors and insulators
Boxes and housings
Hermetic sealed envelope type
C174S050510, C174S050510, C336S096000
Reexamination Certificate
active
06713676
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates generally to the field of electronic devices and, more specifically, to a system and method for converting a DC input voltage to a DC output voltage.
BACKGROUND OF THE INVENTION
DC—DC converter systems are used to convert a direct current (“DC”) input voltage to a direct current (“DC”) output voltage that is normally at a different magnitude than the DC input voltage. There is two basic types of DC—DC converters: Buck and Boost converters. The Buck converter produces a lower DC output voltage from a higher input voltage, and the Boost converter produces a higher DC output voltage from a lower DC input voltage. Many Boost converters are used in portable applications such as DSP applications for cell phones where space and printed circuit board area is a premium concern. Therefore, it is desired that DC—DC converter systems be small in addition to being reliable and manufactured at low cost.
Some DC—DC converter systems are manufactured using printed circuit boards. An integrated circuit and inductor used for these converter circuits are discrete components, which requires a large amount of space as well as higher cost due to increased material needs and manufacturing steps. Another problem with manufacturing DC—DC converter systems using printed circuit boards is that the traces on printed circuit boards caused radio jamming because of the high frequency signals the traces carry. Dual in-line package (“DIP”) integrated circuits have been recently developed to address some of the problems of printed circuit board DC—DC conversion systems. These DIP's address a few of the problems of printed circuit board applications by reducing the space needed as well as reducing the electro-magnetic interference associated with printed circuit board methods. However, these DIP solutions can be expensive to manufacture and can be limited in their performance because of the non-ideal magnetic properties of their inductors.
SUMMARY OF THE INVENTION
The challenges in the field of electronic devices continue to increase with demands for more and better techniques having greater flexibility and adaptability. Therefore, a need has arisen for a new system and method for converting a DC input voltage to a DC output voltage.
In accordance with the present invention, a system and method for converting a DC input voltage to a DC output voltage is provided that addresses disadvantages and problems associated with previously developed systems and methods.
A system for converting a DC input voltage to a DC output voltage includes at least one integrated circuit die electrically coupled to a leadframe. An inductor is also coupled to the leadframe and electrically coupled to the integrated circuit die. An inductor casing generally surrounds the inductor, and a molding encapsulates the integrated circuit die, a portion of the leadframe, and a portion of the inductor. The integrated circuit die and the inductor are operable to receive the direct current input voltage and to convert the direct current input voltage to the direct current output voltage.
A method for converting a DC input voltage to a DC output voltage includes bonding at least one integrated circuit die to a leadframe, and electrically coupling the integrated circuit die to the leadframe. The method further includes coupling an inductor to the leadframe, and electrically coupling the inductor to the integrated circuit die. The method also includes generally surrounding the inductor with an inductor casing, and encapsulating the integrated circuit die, a portion of the leadframe, and a portion of the inductor with a molding. In addition, the method includes receiving the direct current input voltage and converting the direct current input voltage to the direct current output voltage.
Embodiments of the invention provide numerous technical advantages. For example, a technical advantage of one embodiment of the present invention is that less space is needed for the DC—DC converter system, which allows new applications such as small portable DSP applications. Another technical advantage of one embodiment of the present invention is that the design of DC—DC converter solutions becomes easier for the end user because selection of the inductor and integrated circuit die is already performed before being shipped to the end user. A further technical advantage of one embodiment of the present invention is that there is less electromagnetic interference associated with the DC—DC converter system because there are no traces between the coil and integrated circuit on a printed circuit board that carry high frequency signals. A still further technical advantage of one embodiment of the present invention is that there is a reduction in total costs for the DC—DC converter system because of less fabrication steps and less material needs.
Other technical advantages are readily apparent to one skilled in the art from the following figures, descriptions, and claims.
REFERENCES:
patent: 4780795 (1988-10-01), Meinel
patent: 5010314 (1991-04-01), Estrov
patent: 5815381 (1998-09-01), Newlin
“Isolated 1W Single Output SM DC-DC Converters,” NTE Series,Newport Components, issue 4, Dec. 1999, DCR 2446.
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