(12)
`
`United States Patent
`Kuennenet al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 6,825,620 B2
`Nov. 30, 2004
`
`US006825620B2
`
`INDUCTIVELY COUPLED BALLAST
`....cccseeees 315/248
`2/1907 Hewitl
`843,534 A
`4/1915 Klorer .....
`weve 403/57
`1,137,333 A
`CIRCUIT
`
`1,604,870 A LO/1926 ASIAN .......ceceences sree 403/396
`1,803,571 A
`5/1931 Ulan .....c..cccceccesereres 362/92
`(75)
`Inventors: Roy W. Kuennen, Caledonia, MI (US);
`Scott A. Mollema, Grand Rapids, MI
`(US); David W. Baarman, Fennville,
`MI (US); Ronald C. Markham, Grand
`Rapids, MI (US); Dennis J. Denen,
`Westerville, OH (US)
`
`(54)
`
`
`
`(List continued on next page.)
`
`FOREIGN PATENT DOCUMENTS
`
`(73)
`
`Assignee:
`
`Access Business Group International
`LLC, Ada, MI (US)
`
`(*)
`
`Notice:
`
`Subject to any disclaimer, the term of this
`patent
`is extended or adjusted under 35
`U.S.C. 154(b) by 156 days.
`
`(21)
`
`Appl. No.: 10/246,155
`
`Filed:
`
`(22
`
`(65)
`
`Sep. 18, 2002
`Prior Publication Data
`
`US 2003/0015479 Al Jan. 23, 2003
`
`AT
`AU
`DE
`DE
`DE
`
`370929
`A-61741/86
`2029468
`4100272
`9012505
`
`5/1983
`2/1988
`12/1971
`7/1991
`8/1991
`
`(List continued on next page.)
`
`OTHER PUBLICATIONS
`
`“Best of Show”, Fortune, Feb. 17, 2003.
`
`(List continued on next page.)
`
`Related U.S. Application Data
`
`Continuation-in-part of application No. 10/175,095, filed on
`Jun. 18, 2002, now Pat. No. 6,673,250, which is a continu-
`ation-in-part ofapplication No. 09/592,194, filed on Jun. 12,
`2000, now Pat. No. 6,436,299.
`Provisional application No. 60/140,159, filed on Jun. 21,
`1999, and provisional application No. 60/140,090, filed on
`Jun. 21, 1999,
`
`Int. C1) cocecccccceeeeeseesseesseeeeeee HOSB 37/02
`
`ULS. Ch. veces. 315/224; 315/276; 315/283;
`315/291
`.................... 315/209 R, 219-220,
`Field of Search.
`315/224—225, 244, 291, 302, 307, DIG. 7,
`57, 62, 248, 276, 283
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`Primary Examiner—Tbuy Vinh Tran
`(74) Attorney, Agent, or Firm—Warner Norcross & Judd
`LLP
`
`(57)
`
`ABSTRACT
`
`Aballast circuit is disclosed for inductively providing power
`to a load. The ballast circuit includes an oscillator, a driver,
`a switching circuit, a resonant tank circuit and a current
`sensing circuit. The current sensing circuit provides a cur-
`rent feedback signal to the oscillator that is representative of
`the current in the resonant tank circuit. The current feedback
`signal drives the frequency of the ballast circuit causing the
`ballast circuit to seek resonance. The ballast circuit prefer-
`ably includes a current
`limit circuit
`that
`is inductively
`coupled tothe resonant tank circuit. The current limit circuit
`disables the ballast circuit when the current in the ballast
`circuit exceeds a predetermined threshold or falls outside a
`predetermined range.
`
`602,966 A
`
`4/1898 Wallach .0...4:.ccccciccanees 362/219
`
`59 Claims, 15 Drawing Sheets
`
`fs. 3
`.
`i Pea eee
`plan (ie
`| ieee} PL
`oe
`[oemHt | =I
`: Vs —— es|c
`
`Ss
`
`
`
`
`
`
`ver
`» Ltt
`maior}ae
`[ise
`
`ANKER 1008
`ANKER1008
`
`1
`
`

`

`
`
`PRPrrrrrrrrrrrrrrrrrrrrrrereeererrrerrrreererErrerererereeerrree
`
`1,852,740
`2,199,107
`2,265,475
`2,353,063
`2,686,866
`2,726,116
`2,731,547
`3,047,765
`3,292,579
`3,550,682
`3,551,091
`3,628,086
`3,641,336
`3,743,989
`3,746,906
`3,867,661
`3,885,185
`3,885,211
`3,923,663
`3,938,018
`4,005,330
`4,010,400
`4,017,764
`4,038,625
`4,093,893
`4,101,777
`4,117,378
`4,282,563
`4,300,073
`4,389,595
`4,414,489
`4,615,799
`4,637,434
`4,675,573
`4,675,638
`4,752,401
`4,762,613
`4,772,991
`4,800,328
`4,812,702
`4,816,977
`4,818,855
`4,838,797
`4,854,214
`4,857,204
`4,894,591
`4,954,756
`4,958,266
`4,968,437
`4,971,687
`4,972,120
`4,977,354
`5,030,889
`5,039,903
`5.041.763
`5,070,293
`5,101,332
`5.122.729
`5,141,325
`5,146,140
`5,158,361
`5,173,643
`5,184,891
`5,216,402
`5,229,652
`5,267,997
`5,280,416
`5,289,085
`5,300,860
`5,301,096
`
`U.S. PATENT DOCUMENTS
`
`4/1932
`4/1940
`12/1941
`7/1944
`8/1954
`12/1955
`1/1956
`7/1962
`12/1966
`12/1970
`12/1970
`12/1971
`2/1972
`WAIT3
`F/1973
`2/1975
`5/1975
`5/1975
`12/1975
`2/1976
`1/1977
`3/1977
`4/1977
`T1977
`6/1978
`FA9T8
`9/1978
`8/1981
`11/1981
`6/1983
`11/1983
`10/1986
`1/1987
`6/1987
`6/1987
`6/1988
`8/1988
`9/1988
`1/1989
`3/1989
`3/1989
`4/1989
`6/1989
`8/1989
`8/1989
`1/1990
`9/1990
`9/1990
`11/1990
`11/1990
`11/1990
`12/1990
`T1991
`8/1991
`8/1991
`12/1991
`3/1992
`6/1992
`8/1992
`9/1992
`10/1992
`12/1992
`2/1993
`6/1993
`7/1993
`12/1993
`1/1994
`2/1994
`4/1994
`4/1994
`
`
`
`
`PRGATE enecyeeercnenanscewsneee
`362/304
`Kibbe ...
`eit 359/801
`Fodor...
`315/76
`GS cssecuves
`40/406
`Williams ..
`362/231
`Barner
`.....
`eins 239/18
`Callard .....
`seven OZPQS7
`Vichill
`......
`313/318.08
`Buchanan .
`veers 119/245
`Fowler .....
`eee 166/338
`Veloz wisi.
`
`ee 210/251
`Nuckolls ..
`... 315/80
`Boin .....s00
`.. 362/183
`Nicolas et al.
`wee 336/5
`Cardwell, Jr.
`..........
`313/318.04
`Waltz et al.
`............-
`. 313/26
`THeéy scsvs
`313/318.03
`Gulai
`.. 320/108
`
`210/151
`320/140
`
`......
`Glascock, Jr. et al.
`315/248
`Hollister .........+6
`
`315/57
`Anderson sancccsneecs
`315/248
`Tompkinset al. v.00...
`336/83
`Anderson .......
`-. 315/48
`
`Reid?
`escczcyeces
`.. 250/436
`Glascock, Jr. spusitsits
`315/248
`OWES ercersenennaernn
`362/216
`Skwirutet al.
`
`wes 315/53
`Kameiet al.
`....
`
`vee 315/57
`
`YOUNZ wees
`w. 315/51
`Mortensen ...
`eevee 210/177
`Moen ..........
`137/625.66
`Miram etal.
`
`veseee
`315/94
`Szabo wvcccccee
`336/83
`Bodenstein ..
`210/476
`Snowball
`.....
`
`210/192
`Wood .........
`362/287
`
`Bolger etal.
`vee 320/106
`Anderson ....
`eevee 313/153
`Sorensen ........
`
`eevee 362/448
`Mongeon etal.
`wees 235/440
`Dodier
`...........
`a 439/138
`Lowe....
`... 84/404
`Joklik ...
`seed 210/695
`Willing .......
`vee 315/248
`Wood etal.
`.....
`.. 315/39
`Sorensen et al. wo...
`362/360
`Noll et al... ee
`210/748
`Anderson ....
`eevee 604/248
`
`Witting .
`.. 313/638
`Bergervoet¢eltal. —
`- 315/248
`El-Hamamsyetal. ..
`315/200 R
`Farrall: sis iincheuiaesaty
`313/160
`Sullivan et al.
`". 315/176
`Ishii et al.
`...
`wennay
`SSOOID
`Hsia ..iseass
`ses 362/401
`Itoga etal.
`weve 323/347
`Huang ........
`eevee 362/413
`Piejak et al.
`.. 315/248
`a 362/414
`Huang ..
`Sullivan et al.
`vesss 315/276
`
`.. 362/419
`Shpigel
`.......
`Carosa .....
`a 336/66
`wees 307/104
`Hough .....
`Farin et al...
`.... 606/38
`wes 362/98
`...
`Hartley et al.
`.. 136/244
`..
`Godyaket al.
`.. 315/39
`Godyaket alow...
`RlOnie CE W1,)
`..cerscnercenes
`363/37
`
`
`
`
`
`
`
`S 6,825,620 B2
`Page 2
`
`
`
`PPPrrererrrrrrrerrrerrererrrerrrrrrrrrrrrrrrerrrre
`
`BL
`Bl
`Bl
`Bl
`B2
`
`5/1994
`8/1994
`5/1995
`6/1995
`9/1995
`10/1995
`10/1995
`11/1995
`4/1996
`7/1996
`8/1996
`1/1997
`3/1997
`4/1997
`8/1997
`10/1997
`10/1997
`2/1998
`5/1998
`5/1998
`8/1998
`9/1998
`11/1998
`11/1998
`11/1998
`5/1999
`6/1999
`F/1999
`7/1999
`7/1999
`7/1999
`9/1999
`9/1999
`9/1999
`11/1999
`11/1999
`12/1999
`2/2000
`2/2000
`2/2000
`6/2000
`9/2000
`12/2000
`12/2000
`12/2000
`2/2001
`2/2001
`4/2001
`6/2001
`7/2001
`8/2001
`8/2001
`9/2001
`10/2001
`10/2001
`11/2001
`12/2001
`1/2002
`2/2002
`8/2002
`10/2002
`7/2003
`
`
`
`
`
`
`............0.. 250/497.1
`Glavish.
`VANE cssocsanes
`++ 362/402
`Shackle ...
`«. 315/219
`Russell
`.......
`+ 307/104
`Boyse@ al:
`saciassaumzens 363/24
`Parks et al.
`.
`.. 307/104
`Young et al.
`......:0:+++ 307/104
`Hendrickson .....
`i 313/318.09
`Takeuchi et al. .............. 336/83
`McEachernetal. ........_ 307/104
`Shirai et al.
`.......
`wove SQO/2
`Graber .......
`we 315/85
`Markham ...
`eee 210/87
`Robb.
`......05:
`«. 340/479
`Yang .. musa SOQ352
`Davenportet al.
`were SBS/31
`McEacherm ......ccccee. 320/2
`Meyer .........
`=. 362/287
`Hirai et al.
`.
`w. 307/104
`Ranganath ........0... 315/224
`Beasley: aciianninnc 315807
`Esser et al.
`.
`. 307/104
`
`Nishizawa ..
`. 307/104
`Jennings oo..."340/392.4
`Godyak et al.
`............. 315/248
`McCamant
`....
`we 315/57
`Qian et al.
`......
`w. 315/307
`Uran0 .oeceeceeceseseseeeereeee 363/92
`Zeng et al. cece 315/224
`vee 210/91
`Inakagata et al.
`
`Nakamaet al. ....
`w 320/107
`..
`«-- 307/107
`Tamura et al.
`
`ssssiv
`-+ 362/490
`Lamser
`
`VanLerserghe
`w+ 320/108
`WeSE scares
`wee 362/86
`
`w+. 313/493
`bee sini
`
`Seelig .....
`w 307/104
`Holzer
`....
`++ 313/493
`+ 362/183
`Martin et ‘ihe:
`w 320/108
`Brockmann ....
`
`wee 356/212
`Onoet al.
`Brockmann et al.
`- 320/108
`Tachikawa...........+"318/568.11
`PRERET csecevsescanearszencssxee 600/424
`
`. 315/209 R
`Green .....
`
`.....
`wee 315/244
`Boys et al.
`
`Kohneet al.
`...
`veo 313/493
`..........
`Incerti
`315/185 S
`Lin ..........
`w. 362/96
`Mueller et al.
`... 607/60
`Stobbe v.05
`340/10.34
`
`Dolan .....ccsccsee
`+ 362/414
`MacLennanet al.
`» 315/39
`Jang etal. occ. 363/17
`Holzer
`.......
`+ 313/493
`Dickson s.isscsssescccsssess 362/33
`MacLennanet al. ........ 315/248
`Goral
`....cccceecereeeseeenees 515/86
`Mueller et al,
`see 607/60
`Baarman et al.
`w. 210/748
`Seelig et al.
`...........000 307/133
`Scheible et al.
`............. 307/104
`
`
`
`
`
`5,311,028
`5,339,233
`5,416,388
`5,422,519
`5,450,305
`5,455,466
`5,455,467
`5,465,025
`5 506,560
`5,536,979
`5,550,452
`5,594,304
`5,611,918
`5,619,182
`5,653,531
`5,675,677
`5,680,028
`5,716,126
`5,747,894
`5,747,942
`5,796,216
`5,814,900
`5,831,348
`5,831,516
`5,834,905
`5,905,343
`5,914,572
`5,923,544
`5,925,985
`5,928,505
`5,929,598
`5,949,155
`5,951,155
`5,952,814
`5,980,056
`5,990,611
`6,005,304
`6,020,682
`6,027,225
`6,028,413
`6,075,433
`6,118,249
`6,160,371
`6,161,032
`6,166,494
`6,188,179
`6,194,828
`6,218,785
`6,241,359
`6,263,247
`6,275,143
`6,280,066
`6,291,936
`6,301,128
`6,307,316
`6,322,226
`6,326,739
`6,339,296
`6,345,203
`6,436,299
`6,462,432
`6,597,076
`
`FOREIGN PATENT DOCUMENTS
`
`DE
`DE
`DE
`DE
`EP
`EP
`GB
`
`4238388
`4421253
`4412957
`19540854
`0 433 752 Al
`0825577
`1349788
`
`*
`
`5/1994
`3/1995
`10/1995
`5/1997
`6/1991
`2/1998
`4/1974
`
`2
`
`

`

`US 6,825,620 B2
`Page 3
`
`2388715 A
`2388716 A
`8-31585
`WO 97/17761
`WO 97/26705
`WO 00/22892
`WO 010/32298
`WO 01/26427
`WO 01/26431
`
`11/2003
`11/2003
`2/1996
`5/1997
`7/1997
`4/2000
`6/2000
`4/2001
`4/2001
`
`wo
`wo
`
`WO 03/096361
`WO 03/L05311
`
`11/2003
`12/2003
`
`OTHER PUBLICATIONS
`
`“Splashpower”, www.splashpower.com, Feb. 11, 2003.
`“Mobilewise”, www.mobilewise.com, Feb. 11, 2003.
`
`* cited by examiner
`
`3
`
`

`

`U.S. Patent
`
`Nov. 30, 2004
`
`Sheet 1 of 15
`
`US 6,825,620 B2
`
`
`
`4
`
`

`

`U.S. Patent
`
`Nov. 30, 2004
`
`Sheet 2 of 15
`
`US 6,825,620 B2
`
`
`
`5
`
`

`

`U.S. Patent
`
`Noy. 30, 2004
`
`Sheet 3 of 15
`
`US 6,825,620 B2
`
`ogi
`
`vZl
`
`etl
`
`20
`
`
`
`WADE{SOO
`
`
`
`“1padnesAeayanpuy
`
`BUT[SsyUOD
`
`Och
`
` PAQoSues
`
`wdaraist,
`
`6
`
`
`
`
`
`
`

`

`Sheet 4 of 15
`
`US 6,825,620 B2
`
`Noy. 30, 2004
`
`U.S. Patent
`
`7
`
`

`

`U.S. Patent
`
`Noy. 30, 2004
`
`Sheet 5 of 15
`
`US 6,825,620 B2
`
`
`
`8
`
`

`

`U.S. Patent
`
`Noy. 30, 2004
`
`Sheet 6 of 15
`
`US 6,825,620 B2
`
`308
`
`60
`
`300
`
`304
`
`External Control Mechanism
`
`
`
`i
`
`312
`
`
`
`9
`
`

`

`U.S. Patent
`
`Nov. 30, 2004
`
`Sheet 7 of 15
`
`US 6,825,620 B2
`
`ent320
`
`Fic.7
`
`10
`
`10
`
`

`

`U.S. Patent
`
`Noy. 30, 2004
`
`Sheet 8 of 15
`
`US 6,825,620 B2
`
`
`
`Sarogc
`
`
`gzPLritZivabwe90%
`
`|
`361+
`
`b
`92
`
`ret
`
`96f
`Jit
`
`rEzor
`
`Are
`
`x01
`
`+0b
`
`cor
`
`AOl
`
`CONTROL
`UNIT
`
`11
`
`

`

`U.S. Patent
`
`Nov. 30, 2004
`
`Sheet 9 of 15
`
`US 6,825,620 B2
`
`
`
`12
`
`12
`
`

`

`U.S. Patent
`
`Nov. 30, 2004
`
`Sheet 10 of 15
`
`US 6,825,620 B2
`
`110
`
`488
`
`482
`
`484
`
`470
`
`180
`
`
`
`FIG.
`
`14
`
`490
`
`ggg
`
`FIG.
`
`l2
`
`13
`
`13
`
`

`

`U.S. Patent
`
`Nov. 30, 2004
`
`Sheet 11 of 15
`
`US 6,825,620 B2
`
`118
`
`184
`
`yB4
`
`102
`
`CONTROL
`UNIT
`
`522
`
`4.7K #19
`
`O
`10K
`
`an
`
`S36
`
`‘otur +19
`
`1B4
`
`
`
`FIG, 13
`
`14
`
`14
`
`

`

`U.S. Patent
`
`Nov. 30, 2004
`
`Sheet 12 of 15
`
`US 6,825,620 B2
`
`184
`
`184
`
`568
`
`+19¥
`
`+19¥
`
`120
`
`mePs
`Ww
`
`180
`
`F\G.-14
`
`272
`
`352
`
`10K
`
`362
`
`102
`
`15
`
`

`

`U.S. Patent
`
`Nov. 30, 2004
`
`Sheet 13 of 15
`
`US 6,825,620 B2
`
`606
`
`600
`
`608
`
`602
`
`604
`
`10
`
`FIG. 15
`
`16
`
`

`

`U.S. Patent
`
`Nov. 30, 2004
`
`Sheet 14 of 15
`
`US 6,825,620 B2
`
`
`
`a|QeusISelleqg
`
`
`
`
`
`™80
`
`17
`
`
`
` 1D“70219DAODAawhon|)
`
`pel70APOL
`
` 199]yv:1SWOINYsJO}yNOWIDpwryuUEUNDSXgq)7WYSXozz
`
`|821
`
`NIA9,7OO
`
`17
`
`

`

`U.S. Patent
`
`Nov. 30, 2004
`
`Sheet 15 of 15
`
`US 6,825,620 B2
`
`232
`
`218'
`
`FIG. 17
`
`18
`
`

`

`US 6,825,620 B2
`
`1
`INDUCTIVELY COUPLED BALLAST
`CIRCUIT
`
`ws
`
`This application is a continuation-in-part of U.S. patent
`application Ser. No. 10/175,095 entitled Fluid Treatment
`System, which wasfiled on Jun. 18, 2002 now U.S. Pat. No.
`6,673,250, which is a continuation-in-part of U.S. patent
`application Ser. No. 09/592,194 entitled Fluid Treatment
`System, which wasfiled on Jun. 12, 2000 now U.S. Pat. No.
`6,436,299, U.S. patent application Ser. No. 09/592,194
`claims the benefit under 35 U.S.C. $119(e) of U.S. provi-
`sional patent application Ser. No. 60/140,159 entitled Water
`Treatment System with an Inductively Coupled Ballast,
`which was filed on Jun. 21, 1999, and U.S. provisional
`patent application Ser. No. 60/140,090 entitled Port-of-Use
`Water Treatment System, which wasfiled on Jun. 21, 1999.
`This application hereby incorporates by reference U.S.
`patent application Ser. No. 09/596,416 entitled Point-of-Use
`Water Treatment System, which wasfiled on Jun. 12, 2000,
`“3
`and U.S. patent application Ser. No. 10/133,860 entitled 2
`Inductively Powered Lamp Assembly, which was filed on
`Apr. 26, 2002.
`
`15
`
`FIELD OF THE INVENTION
`
`The present invention generally relates to ballasts and
`more particularly,
`to an inductively coupled ballast
`for
`non-contact powertransfer to a secondary circuit or load.
`
`BACKGROUND OF THE INVENTION
`
`Ballasts are commonly used to supply power to a wide
`variety of electrically powered components. Often ballasts
`are connected directly to the component (or
`load),
`for
`example, by “permanent” connections, such as wires or
`soldered leads on a circuit board, or by “removable”
`connections, such as plugs or other connectors. Direct
`electrical connections present a number of problems. First,
`direct electrical connections makeit difficult to install and
`remove the load from the ballast. With permanent
`connections, the electrical leads must be soldered or other-
`wise secured directly between the ballast and the load. If the
`ballast or the load is damaged, replacement is complicated
`by the permanent connections. Removable connections
`make separation of the ballast and the load easier, but still
`require some manual manipulation. Removable connectors
`are also subject to corrosion and may be inadvertently or
`unintentionally disconnected,
`for example, by vibrations.
`Second, in many environments,direct electrical connections
`must be insulated from the environment to prevent damage
`to the circuit. For example, in wet environments, exposed
`electrical connections are subject to a short circuit. Third,
`direct electrical connections provide a direct and essentially
`unimpeded path for electricity to flow between the ballast
`and the load. As a result, power surges and other potentially
`damaging abnormalities in one element can be directly
`transfer to the other, thereby permitting problems in one
`component to damage or even destroy the other,
`To address these and other significant problems, there is
`an increasing trend to replace conventional direct electrical
`connections with inductive connections.
`Inductively
`coupled systems provide a number of significant advantages
`over direct connections. First, inductive couplings do not
`include permanent or removable physical connectors.
`Instead, the secondary coil of the load (or secondary circuit)
`simply needs to be placed in the close proximity to the
`primary coil of the ballast. This greatly simplifies installa-
`tion and removal ofthe load. Second, the inductive coupling
`
`30
`
`40
`
`45
`
`50
`
`aa
`
`60
`
`2
`provide a significant level of isolation between the ballast
`and the load. This isolation can protect one component from
`power surges and other potentially damaging abnormalities
`in the other component.
`Unfortunately, conventional inductively coupled ballasts
`suffer from a numberof problems associated primarily with
`efficiency. To provide maximum efficiency,it is desirable for
`the circuit to operate at resonance, Conventional ballasts are
`designed to operate at resonance by carefully selecting the
`components of the ballast in view ofthe precise character-
`istics of the load. Any variation in the load can move the
`circuit dramatically out of resonance. Accordingly, conven-
`tional ballasts require very precise selection of the compo-
`nents of the ballast circuit and secondary circuit. In some
`applications,
`the impedance of the secondary circuit will
`vary over time, thereby changing the resonant frequency of
`the circuit. For example,
`in many conventional
`lighting
`applications, the impedance of the lamp will vary as the
`lamp is heated and will also vary overthe life of the lamp.
`Asa result of these changes, the efficiency of conventional,
`fixed-frequency ballasts will vary over time.
`Conventional ballast control circuits employ bipolar tran-
`sistors and saturating transformers to provide power. The
`ballast control circuits oscillate at frequencies related to the
`magnetic properties of the materials and winding arrange-
`ments of these transformers, Circuits with saturating trans-
`former oscillators produce an output in the category of a
`square wave, require the transistors of the half bridge to
`hard-switch under load and require a separate inductor to
`limit
`the current
`through the load. Conventional circuits
`chopthe available power supply voltage, developing voltage
`spikes at the corners of the square wave as a consequence of
`the current limiting inductor. Inductive couplings rely on
`electromagnetic induction to transfer power from a primary
`coil to a secondary coil. The amount of current induced in
`the secondary coil
`is a function of the changes in the
`magnetic field generated by the primary coil. Accordingly,
`the amount of current
`transferred through an inductive
`coupling is dependent,
`in part, on the waveform of the
`current driving the primary. A square waveform has rela-
`tively small regions of change and therefore provides rela-
`tively inefficient transfer of power.
`These and other deficiencies in prior ballasts are
`addressed by the present invention.
`SUMMARY OF THE INVENTION
`
`The present invention discloses an inductively powered
`ballast circuit having a current sensing circuit that automati-
`cally adjusts the frequency of the ballast to maintain opera-
`tion of the ballast at or near unity powerfactor.
`In one embodiment, the inductively coupled ballast circuit
`is a self-oscillating half-bridge switching design that oper-
`ates at high frequencies. In addition, the inductively coupled
`ballast circuit self-oscillates partly as a function of the
`current sensing circuit to maintain resonance, uses MOSFET
`transistors as switching elements, and is designed to accom-
`modate an air-core transformer coupling arrangement.
`One embodiment of the inductively coupled ballast circuit
`includes a control circuit, an oscillator, a driver, a half-
`bridge switching circuit, and a series resonant tank circuit.
`The secondary circuit preferably includes a secondary coil
`and a load. During operation,
`the control circuit provides
`electrical signals to the oscillator, which, in turn, provides
`electrical signals to direct the driver. The driver then causes
`the half-bridge switching circuit to become energized. The
`half-bridge switching circuit energizes the series resonant
`
`19
`
`19
`
`

`

`US 6,825,620 B2
`
`3
`tank circuit, which includes a primary coil. Once the series
`resonant tank circuit, and consequently the primary coil, is
`energized,
`the secondary coil becomes inductively
`energized, thereby providing power to the load.
`In one embodiment, the resonant frequency for the induc-
`tively coupled ballast circuit is about 100 kHz. In addition,
`the secondary circuit preferably resonates at about 100 kHz
`as well. The resonant frequency of operation can be adjusted
`up or down by the control unit to accommodate for conve-
`nient component selection.
`In addition, selection of the
`resonant frequencyis a function of the component selection
`in the series resonant tank and the characteristics of the
`secondary circuit.
`An interesting feature of the inductively coupled ballast
`circuit is the inductive coupling. The series resonant tank
`circuit includes an inductive coupler. In one embodiment,
`the inductive coupler is positioned adjacent the secondary
`coil with an air gap therebetween to form an air core
`transformer. When voltage is applied to the inductive
`coupler, magnetic flux in the air gap induces voltage in the
`secondary coil thereby energizing the secondary load.
`Another interesting feature of the inductively coupled
`ballast circuit involves the air gap of one embodiment. The
`air gap is the distance between the inductive coupler and the
`secondary coil. The air gap may be selected to provide a
`current limiting function. In addition, the air gap provides a
`magnetic flux path for inducing sufficient voltage in the
`secondary coil to establish and maintain an operating point
`for the secondary load.
`Yet another interesting feature involves the frequency of
`operation of the inductively coupled ballast circuit. Both the
`series resonant tank and the secondary load may be tuned by
`proper selection of components to operate at a similar
`resonant
`frequency.
`In addition,
`impedance matching
`between the series resonant tank and the secondary load may
`occurat the resonant frequency. Accordingly, power transfer
`from the inductive coupler to the secondary coil may be
`optimized at a resonant frequency to maximize power effi-
`ciency.
`Still another interesting feature involves self-oscillation
`of the inductively coupled ballast circuit with the oscillator.
`The oscillator may include feedback control for monitoring
`the series resonance tank. The feedback control may allow
`the oscillator to adjust the frequency to minimize reflected
`impedance from the secondary circuit. Adjusting the fre-
`quency to maintain resonance minimizes the reflected
`impedance and maintains optimum powertransfer as the
`impedance of the secondary circuit varies,
`In another aspect,
`the present
`invention preferably
`includes a current
`limit circuit
`that monitors the ballast
`circuit and disables the ballast circuit if the current to the
`
`limit
`primary exceeds a desired threshold. The current
`circuit protects both the load and the ballast circuit from
`excessive current. The current
`limit circuit
`is preferably
`latched to keep the ballast circuit disabled until reset, for
`example, by a manual reset switch.
`In an alternative embodiment,
`the current limit circuit
`may be configured to disengage the ballast circuit if the
`current
`falls outside of a desired operating range. This
`embodiment ts particularly useful in application where the
`load may be damaged or function improperly when operat-
`ing under low current.
`These and other features and advantages of the invention
`will become apparent upon consideration of the following
`detailed description of the presently preferred embodiments
`of the invention, viewed in conjunction with the appended
`drawings.
`
`4
`DETAILED DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a perspective view of a main housing of the
`water treatment system with its top shroud removed and a
`filter assembly and the ultraviolet lamp assembly removed
`from the base unit.
`
`ws
`
`FIGS. 2A-C are exploded perspective views of major
`components of the water treatment system.
`FIG. 3 depicts a block diagram of the major circuits and
`assemblies of the water treatment system.
`FIG. 4 depicts a block diagram ofthe inductively coupled
`ballast circuit.
`
`FIG. 3 is an electrical circuit schematic ofa portion of the
`inductively coupled ballast circuit,
`the ballast
`feedback
`circuit and the interlock circuit.
`
`15
`
`lamp
`lamp
`
`the resonant
`FIG. 6 depicts the secondary coil,
`circuit and the ultraviolet
`lamp of the ultraviolet
`assembly.
`FIG. 7 is an electrical circuit schematic of the starter
`circuit.
`FIG. 8 illustrates an electrical circuit schematic of the
`radio frequency identification system used in the water
`treatment system
`FIG. 9 is an electrical circuit schematic ofthe flow sensor
`circuit,
`FIG. 10 is an electrical circuit schematic of the ambient
`light sensor circuit.
`FIG. 11 is an electrical circuit schematic of the ultraviolet
`light sensor circuit.
`FIG. 12 is an electrical circuit schematic of the ambient
`
`temperature sensor circuit.
`FIG, 13 is an electrical circuit schematic of the audible
`generation circuit.
`FIG. 14 is an electrical circuit schematic of the commu-
`nication port.
`FIG. 15 is a plurality of waveforms representing operation
`of the current sensing circuit.
`FIG. 16 is an electrical circuit schematic of the current
`limit circuit.
`
`FIG. 17 is an electrical circuit schematic of a portion of
`an alternative current feedback circuit.
`
`DETAILED DESCRIPTION OF THE
`ILLUSTRATED EMBODIMENT OF THE
`INVENTION
`
`invention is directed to an inductively
`The present
`coupled ballast circuit that is capable of providing powerto
`a wide variety of electrically powered components in numer-
`ous applications. For purposes of disclosure, embodiments
`ofthe ballast circuit will be described in connection with a
`
`water treatment system, and more specifically in connection
`with the powering of an ultraviolet lamp in a water treatment
`system. Although described in connection with this particu-
`lar application, the present invention is well-suited for use in
`providing power to other
`types of lamps, such as
`incandescent, fluorescent and halogen lamps used in numer-
`ous lighting applications, such as indoor and outdoor light
`fixtures, desk lamps, outdoor signage, decorative lighting,
`automotive lighting, underwater lighting, intrinsically safe
`lighting, and landscapelighting, to name only a few lighting
`configurations and applications. The present
`invention is
`also well suited for providing power to non-lighting
`components, such as integrated battery chargers in various
`electronic components, including cell phones, personal digi-
`tal assistants and the like.
`
`30
`
`40
`
`45
`
`50
`
`aa
`
`60
`
`20
`
`20
`
`

`

`US 6,825,620 B2
`
`5
`Referring to FIG, 1, the present invention, as used in the
`illustrated embodiment, discloses an electronic control sys-
`tem for a water treatment system 10 that generally uses
`carbon-based filters and ultraviolet light to purify water. In
`order to appreciate the present invention,it is helpful to have
`a general background of the mechanical aspects of water
`treatment system 10 for which this illustrated embodiment
`was intended. Water treatment system 10 includes a main
`housing 12, a replaceable ultraviolet lamp assembly 14 and
`a filter assembly 16. The ultraviolet lamp assembly 14 and
`the filter assembly 16 are removable and replaceable from
`the main housing 12. The main housing 12 includes a bottom
`shroud 18, a back shroud 20, a front shroud 22, a top shroud
`24 and an inner sleeve shroud26. A lens 28 accommodates
`a display 106 (see FIG. 3) so that
`information may be
`displayed about the status of the water treatment system LO
`through the display 106. To assemble the water treatment
`system 10,
`the ultraviolet
`lamp assembly 14 is securely
`mounted to the main housing 12 and thereafter the filter
`assembly 16 is mounted over the ultraviolet lamp assembly
`14 and to the main housing 12.
`Asthose skilled in the art would recognize, the replace-
`able ultraviolet lamp assembly 14 may be made in such a
`manner that the ultraviolet lamp assembly 14 may not be
`replaceable.
`In addition,
`those skilled in the art would
`recognize that the replaceable ultraviolet lamp assembly 14
`may be interchanged with several different types of electro-
`magnetic radiation emitting assemblies. As such, the present
`invention should not be construed to cover only systems that
`use ultraviolet lamp assemblies and those skilled in the art
`should recognize that the disclosure of the ultraviolet lamp
`assembly 14 represents only one embodiment of the present
`invention.
`
`Referring to FIGS, 2A-C, the major mechanical compo-
`nents of the water treatment system LO are shown in per-
`spective view, as relevant
`to the present
`invention. As
`illustrated in FIG. 2A, the inner sleeve shroud 26 includes a
`plurality of inner sleeve covers 30, an inlet valve assembly
`32 and an outlet cup assembly 34 with an outlet cup 36. A
`bottom shroud assembly 38is further disclosed that includes
`the bottom shroud 18 along with an inlet assembly 40 and an
`outlet assembly 42. An electronics assembly 44fits securely
`in the bottom shroud 18, the details of which will be set forth
`below in detail. These components are securely mounted to
`the bottom shroud 18, the back shroud 20, the front shroud
`22, the top shroud 24, the inner sleeve shroud 26 and the lens
`28 when the water treatment system 10 is fully assembled.
`A magnet holder 46 and a magnet 48 are also housed in the
`top shroud 24 in the illustrated embodiment.
`Referring to FIG, 2B, the ultraviolet lamp assembly 14
`generally includes a base subassembly 50, a secondary coil
`52, a bottom support subassembly 54, a top support assem-
`bly 56, a pair of quartz sleeves 58, an ultraviolet lamp 60, an
`O-ring 62 and a pair of cooperating enclosure reflector
`subassemblies 64. Generally speaking, the secondary coil
`52, the bottom support subassembly 54 and the enclosure
`reflector subassemblies 64 are connected with the base
`subassembly 50. The enclosure reflector subassemblies 64
`house the pair of quartz tubes 58, the ultraviolet lamp 60 and
`the O-ring 62. The top support assembly 56 fits securely over
`ihe top of the enclosure reflector assemblies 64 when the
`ultraviolet lamp assembly 14 is fully assembled.
`As illustrated in FIG. 2C,the filter assembly 16 generally
`includes a base assembly 66, a filter block assembly 68, a
`filter housing 70 and an elastomeric filter-housing grip 72.
`Generally speaking,the filter block assembly 68fits over the
`base assembly 66 which, in turn, is encapsulated by the filter
`
`ws
`
`15
`
`30
`
`40
`
`45
`
`50
`
`aa
`
`60
`
`6
`housing 70. The filter housing grip 72 fits over the top of the
`filter housing 70, thereby providing a better grip for remov-
`ing the filter housing 70. The filter assembly 16 filters a ow
`of water by directing the flow through the filter block
`assembly 68 before being directed to the ultraviolet lamp
`assembly 14.
`FIG, 3 illustrates an electronic control system LOO for the
`water treatment system 10 generally described above. In the
`illustrated embodiment,
`the water treatment system 10 is
`controlled by a control unit 102, which is preferably a
`microprocessor.Asillustrated in FIG. 4, the control unit 102
`is electrically connected with the inductively coupled ballast
`circuit 103 of the present invention. The ballast circuit 103
`includes the ultraviolet lamp assembly 14 and electronic
`assembly 44, which are inductively coupled as illustrated by
`the dotted line in FIG. 4. This control unit 102 is also
`
`electrically connected to the ultraviolet lamp assembly 14
`through two-way wireless communication, as will be set
`forth in greater detail below. During operation, the control
`unit 102 is capable of generating a predetermined electric
`signal
`that
`is directed to the inductively coupled ballast
`circuit 103, which instantaneously energizes the lamp
`assembly 14 which, in turn, provides high-intensity ultra-
`violet light that treats the flow of water.
`In the illustrated embodiment, the control unit 102 is also
`electrically connected with a flow sensor circuit 104, a
`display 106, an ambient light sensor circuit 108, a visible
`light sensor circuit 110, a power detection circuit 112, an
`ambient temperature sensor circuit 114, an audio generation
`circuit 116, a memory storage device 118, a communications
`port 120, a ballast feedback circuit 122 and a radio fre-
`quency identification system 124. As further illustrated in
`FIG. 3, an ultraviolet
`light radio frequency identification
`transponder 126 is connected with the ultraviolet
`lamp
`assembly 14 and a filter
`radio frequency identification
`transponder 128 is connected with the filter assembly 16.
`The ultraviolet radio frequency identification transponder
`126 and the filter radio frequency identification transponder
`128 communicate with the radio frequency identification
`system 124 using two-way wireless communication, as will
`be set forth in greater detail below.
`Generally speaking, the flow sensorcircuit 104 is used by
`the control unit 102 to determine when water or fluid is
`flowing and to keep track of the volumeof wateror fluid that
`is being processed by the water treatment system 10. The
`display 106 is driven by the control unit 102 and is used to
`display information about the status of the water treatment
`system 10. Several different types of displays are known in
`the art and may be used in the present invention; however,
`the preferred display is a vacuum florescent display. The
`ambient light sensor circuit 108 measures the amount of
`ambient light and, in turn, provides electrical signals to the
`control unit 102 so that it can adjust the intensity of the
`display 106 accordingly.
`The visible light sensor circuit 110 provides the control
`unit 102 with electrical signals related to the intensity level
`of the light that is being emitted by the ultraviolet lamp
`assembly 14. This is important because these signals allow
`the control unit 102 to increase or decrease the intensity of
`the electromagnetic radiation being emitted by the ultravio-
`let
`lamp assembly 14. Those skilled in the art would
`recognize that
`the visible light sensor circuit 110 may be
`interchanged with various electromagnetic radiation sensor
`circuit