Lamp ballast configuration
First Claim
1. A lamp ballast for exciting a gas containing lamp comprising:
- first and second circuit boards, each having first and second major surfaces;
first and second packaged semiconductor switching devices;
a heat sink;
a drive transformer system including first and second control signal outputs;
a power supply input connection;
said first and second circuit boards having their first major surfaces disposed substantially parallel and spaced apart in a direction perpendicular thereto;
the device package having a first major surface and extending from a connection to a first conductor on said first major surface of said first circuit board to a connection to a second conductor on said first major surface of said second circuit board;
said heat sink having a portion extending generally parallel to the plane of said first major surface of said package which is disposed in thermal contact with said package; and
said drive transformer system being disposed between said circuit boards with said device package disposed intermediate said transformer and said heat sink.
1 Assignment
0 Petitions
Accused Products
Abstract
A lamp ballast configuration in which input power is conducted by one circuit board to the switching devices of a half bridge circuit whose output is conducted on a second circuit board with the two circuit boards mounted parallel and spaced apart disposes the device package which extends between the two circuit boards in an exposed position for direct contact to a heat sink. Drive transformers for the switching devices are preferably mounted between the circuit boards and shielded on four of their six sides by a combination of ground planes on the circuit boards and wide, flat ground conductors connecting the ground planes of the two circuit boards. A compact, high efficiency (>91%) RF system is obtained which is suitable for excitation of an electrodeless, high-intensity-discharge lamp.
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Citations
14 Claims
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1. A lamp ballast for exciting a gas containing lamp comprising:
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first and second circuit boards, each having first and second major surfaces; first and second packaged semiconductor switching devices; a heat sink; a drive transformer system including first and second control signal outputs; a power supply input connection; said first and second circuit boards having their first major surfaces disposed substantially parallel and spaced apart in a direction perpendicular thereto; the device package having a first major surface and extending from a connection to a first conductor on said first major surface of said first circuit board to a connection to a second conductor on said first major surface of said second circuit board; said heat sink having a portion extending generally parallel to the plane of said first major surface of said package which is disposed in thermal contact with said package; and said drive transformer system being disposed between said circuit boards with said device package disposed intermediate said transformer and said heat sink. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification