Ballasting network with integral trap

• US 5,477,112 A
• Filed: 04/27/1993
• Issued: 12/19/1995
• Est. Priority Date: 04/27/1993
• Status: Expired due to Fees

• Current Assignee: Electroning Lighting Incorporated
• Original Assignee: Electronic Lighting
• Inventors: Lesea, Ronald A.
• Primary Examiner(s): Pascal, Robert J.
• Assistant Examiner(s): KINKEAD, ARNOLD M
• Application Number:
  US08/053,144
• Time in Patent Office: 966 Days
• Field of Search: 315/219, 315/244, 315/DIG. 7, 315/209 R, 315/247, 315/111.21, 363/24, 363/26, 363/39, 363/40, 363/17, 363/97, 363/134, 363/45, 363/47, 331/113 A, 331/76
• US Class Current: 315/219
• CPC Class Codes: H02M 3/155 using semiconductor devices only
• CPC Class Codes: H05B 41/282 with semiconductor devices H05B41/2806, H05B41/288, H05B41/295 take precedence
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
• CPC Class Codes: Y10S 315/07 Starting and control circuits for gas discharge lamp using transistors

Abstract

Briefly, to reduce switching stresses, employed is a high-frequency AC power source (110) and a current-limiting (ballasting) network (116). The network ( 116 ) includes a high-frequency trap ( 120 ) and an impedance transforming network (122), which is coupled to the AC power source (110) by the trap (120) and which is for connection to a load that includes at least one gaseous discharge (fluorescent) lamp or other non-linear or negative-resistance load (102). The trap, which has the parallel resonant combination of an inductor ( 130 ) and a capacitor ( 132 ), is resonant at a frequency chosen such that the switching-circuit transistor(s) (210, or 230 and 232, or 250 and 252, or 270 and 272, or 708) of the AC power source (110) switch at times when the level of the current (charge flowing) therein and/or the voltage developed there across is zero, preferably, at a frequency slightly higher than a harmonic frequency of the high-frequency AC power source ( 110 ).

Claims

1. A ballast circuit, comprising:

an alternating current (AC) power source (110) including an output switch transistor (204, 224, 244,

     264) for operating at a first frequency;

at least one parallel-resonant trap (120, 276,

     278) connected to be driven by said transistor in the AC power source (110) and including a first capacitor means (132,292,296) and a first inductor means (130, 290,

     294) connected in parallel providing for frequency resonance at a second frequency which is slightly higher in frequency thatn an odd harmonic of said first frequency, wherein said output switch transistor switches at one of a zero-voltage point and a zero-current point according to the relationship of said first frequency to said second frequency; and

a negative-resistance load (102) connected with an impedance transforming network (122) in series with an AC power source (110) and the at least one parallel-resonant trap (120, 276,

     278), said impedance transformer network (122) including-a second inductor means (420) connected to said at least one parallel-resonant trap (120), third inductor means (460), second capacitor means (366), and third capacitor means (370) connected in series with said third inductor means (460) and said second capacitor means (366) across said second inductor means (420), said negative-resistance load (102) being connected across said third capacitor means (370).

2. The ballast circuit of claim 1, wherein:

the at least one parallel-resonant trap is an integral part of the impedance transforming network.

3. The ballast circuit of claim 2, wherein:

said output switch is active for approximately 180 degrees of each cycle of said first frequency.