Dimming control circuit

United States Patent m

Cunningham

[54] DIMMING CONTROL CIRCUIT

[75] Inventor: David W. Cunningham, Los Angeles, Calif.

[73] Assignee: Gregory Esakoff, Huntington Beach, Calif.

[21] Appl. No.: 63,839

[22] Filed: May 11, 1993

Related U.S. Application Data

[63] Continuation of Ser. No. 759,500, Sep. 13, 1991, abandoned.

[51] Int.C1.5 G05F1/00

[52] U.S. CI 315/195; 315/198;

315/199; 315/291; 315/DIG. 4

[58] Field of Search 315/294, 195, 198, 205,

315/250, 252, 313, 314, 315, 312, 324, 295, 296, 297, 199, 291, DIG. 4

[56] References Cited

U.S. PATENT DOCUMENTS

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3,193,728 7/1965 Skirpan 315/251

3,222,573 12/1965 Lord 315/194

3,265,907 9/1966 Kurata et al 307/321

3,290,555 12/1966 Davis 315/194

3,299,319 1/1967 Nomura 315/199

3,358,186 12/1967 Nomura 315/194

3,369,150 2/1968 Malmin 315/194

3,434,039 3/1969 Misencik et al 323/327

3,496,451 2/1970 Duncan 323/326

3,517,259 6/1970 Dotto 315/200

3,523,212 8/1970 Murphy 315/291

3,614,527 10/1971 Wirtz '. 315/199

3,684,919 8/1972 Cramer 315/194

3,757,199 9/1973 Minks 322/28

3,789,211 1/1974 Kramer 315/195

3,927,349 12/1975 Suhren et al 315/205

US005323088A

[ii] Patent Number: 5,323,088 [45] Date of Patent: Jun. 21, 1994

4,057,751 11/1977 Bonsignore et al 315/294

4,093,943 6/1978 Knight 340/220

4,213,075 7/1980 Ericson 315/83

4,241,295 12/1980 Williams, Jr 315/294

4,290,057 9/1981 Knight 340/539

4,395,660 7/1983 Waszkiewicz 315/291

4,478,468 10/1984 Schoen et al 315/291

4,904,906 2/1990 Atherton et al 315/291

5,004,957 4/1991 Cunningham 315/199

FOREIGN PATENT DOCUMENTS

7729136 12/1977 Fed. Rep. of Germany .
4005012 8/1991 Fed. Rep. of Germany .

Primary Examiner—Robert J. Pascal
Assistant Examiner—Haissa Philogene
Attorney, Agent, or Firm—Pretty, Schroeder,
Brueggemann & Clark

[57] ABSTRACT

A dimming control circuit for a plurality of lighting fixtures includes a separate semiconductor power switch, e.g., a silicon-controlled rectifier or SCR, for providing controlled amounts of pulsed, unidirectional electrical current to each lighting fixture. In one embodiment, a pair of SCRs, arranged in parallel, opposed relationship, are controllably pulsed to produce an alternating sequence of positive and negative electrical current pulses, of independently-controlled duration, and oppositely-conducting diodes then connect these SCRs to two separate lighting fixture. One such lighting fixture thus receives the positive current pulses, and the other such lighting fixture thus receives the negative current pulses. In an alternative embodiment, each lighting fixture receives pulsed, unidirectional current directly from a separate, independently-controlled SCR.

22 Claims, 4 Drawing Sheets