United States Patent
`
`119]
`
`Tucker et a1.
`
`1111
`
`[45]
`
`4,308,443
`
`Dec. 29, 1981
`
`INDUCTION COOK-TOP WITH IMPROVED
`TOUCH CONTROL
`
`[54]
`
`[75]
`
`Inventors: Raymond M. Tucker; Clarence L.
`Dyer; Gregory P. Maman, all of
`Cleburne’ Tex,
`
`.
`[73] America: Rangaire Corporation, Cleburne,
`Tex.
`
`[21] APP]. N°-= 35,083
`-
`,
`May 1’ 1979
`[22] Flled‘
`[51]
`Int. Cl.3 ......................... H05B 6/06; H05B 6/ 12;
`Gogc 9/02
`[52] US. Cl. .......................... 219/10.49 R; 219/1077;
`219/506; 307/116; 340/365 C; 340/365 E;
`328/5' ZOO/DIG. 1
`.
`’
`F1eld of Search ..................... 219/10.77, 10.49 R,
`219/10-55 13, 445, 453, 459, 492-494, 490, 497,
`499, 501. 506; ZOO/DIG. 1; 307/116, 126, 96,
`97, 308, 252 K, 252 M, 238, 239, 296; 363/57,
`135, 95, 96; 361/94, 97; 328/48, 71, 5; 340/365
`s, 365 C, 365 E, 366 R, 382, 716; 235/92 CT,
`92 EV, 92 PE; 323/101
`
`[58]
`
`[56]
`
`References Cited
`
`U‘S' PATENT DOCUMENTS
`3,530,310 9/1970 Adelson et a1. ................. 340/365 C
`3,530,499 9/1970 Schroeder .....
`219/1049 R
`
`........ 219/1075
`3,637,970
`1/1972 Cunningham .
`
`3,697,716 10/1972 Komrumpf
`2151/1049 R
`
`3,697,717 10/1972 Kornrumpf
`219/10.49 R
`....... 200/ 167 R
`3,701,869 10/1972 Jacob et a1.
`
`.
`3,710,062
`1/1973 Peters, Jr.
`219/10.49 R
`1/1973 Moreland ......
`3,711,672
`219/10.49 R
`
`.. 219/1o,49 R
`3,715,550 2/1973 Harnden, Jr, ,
`3/1973 Harnden, Jr. .....
`3,719,739
`219/1049 R
`
`........ 219/1041
`3,742,173
`6/1973 Komrumpf et al
`3,742,174 6/1973 Harnden, Jr.
`.
`" 219/10‘49 R
`3,742,175
`6/1973 Harnden,Jr..
`3:8;1818 g
`3,742,178
`6/1973 Harnden, Jr. .
`3,742,179
`6/1973 Harnden, Jr,
`,
`__ 219/1049 R
`
`3,742,337 6/1973 Digneffe ...................... 307/252 B
`...... 219/10.49 R
`3,745,290 7/1973 Harnden, Jr. et a1.
`3,745,450
`7/1973 Wilt ................................. 340/382
`3,761,667
`9/1973 Walden ..................... 219/1049 R
`
`3,761,668- 9/1973 Harnden, Jr. et a1.
`219/10.49 R
`3,770,928 11/1973 Komrumpf et a1.
`........ 219/10.49R
`
`
`
`..
`
`3,775,577 11/1973 Peters, Jr.
`.................... 219/10.49 R
`
`3,777,094 12/ 1973 Peters, Jr. ................ 219/1049 R
`3,781,503 12/1973 Harnden, Jr. et a1
`..... 219/10.49 R
`3,781,504 12/1973 Harnden, Jr. ............ 219/10.49 R
`
`3,781,506 12/1973 Ketchum ........... 219/10.49 R
`
`
`3,781,508 12/1973 Steigerwald .......... 219/10.49 R
`1/1974 Kornrumpf et a1.
`..... 219/10.49 R
`3,786,219
`3,786,220
`1/1974 Harnden, Jr. ................ 219/10.49 R
`3,786,222
`1/1974 Harnden, Jr. ct a1.
`..... 219/10.49 R
`3,796,850 3/ 1974 Moreland et a1.
`........... 219/10.49 R
`3,806,688 4/1974 Mackenzie et al.
`.
`..... 219/1049 R
`
`..... 219/10.49 R
`3,814,888
`6/1974 Bowers et al.
`
`6/1974 Steigerwald .....
`. 219/10.77 x
`3,820,005
`
`..... 219/ 10.77
`3,823,297
`7/1974 Cunningham
`
`. 219/1049 R
`3,843,857 10/1974 Cunningham
`
`3352558 12/1974 McCleerey e! 31.
`-
`219/1049 R
`
`5/1975 Peters, Jr ............. 219/10.49 R
`3,886,342
`6/1975 Peters, Jr. ......... 219/10.49 R
`3,887,781
`
`..... ZOO/DIG. 1
`3,887,848
`6/1975 Larson et a1.
`6/1975 Makenzie .......... 2,9/10‘49 R
`3,889,090
`
`8/1975 Peters, Jr. ......... 219/1049 R
`3,898,410
`
`..... 219/10.49 R
`3,906,181
`9/1975 Hibino et a1.
`3,925,633 12/1975 Partridge .........
`. 219/10.49 R
`
`..
`3,927,336 12/1975 Carlson et al.
`307/116 X
`3,928,744 12/1975 Hibino et a1. ......... 219/10.49 R
`
`219/10.49 R X
`3,932,801
`1/1976 Peters, Jr.
`
`3/1976 Cobb .............. 219/ 10.79
`3,947,652
`3,949,183 4/1976 Usami et a1.
`.
`......... 219/10.49
`
`219/10.49 R X
`3,953,783 4/1976 Peters, Jr.
`
`3,966,426 6/1976 McCoy et a1.
`. 219/10.49 R X
`-------- 219/506 X
`3,974,472
`8/1976 0011115, JY-
`
`. 219/10.49 R
`4,010,342
`3/1977 Austin .......
`3/1977 FosnOUgh et al-
`- 219/1055 B
`4,011,428
`
`9/1977 Sefton et al. ............. 219/497
`4,046,991
`2/1978 Kiuchi et al-
`. 219/10.49 R
`4,074,101
`
`4,081,700 3/1973 Hamilton -------------- 328/5 X
`
`.
`8/1978 Iwai et al.
`4,105,902
`340/365 E X
`
`..
`----- 219/10-77
`4,149,217 4/1979 TUCRCI'
`6/1979 Mason ............................. 219/506 X
`4,158,759
`
`OTHER PUBLICATIONS
`“Power on Reset For Machine Circuits”, IBM Techni-
`cal Disclosure Bulletin, vol. 9, No. 6, Nov. 1966.
`_
`G.E. Semiconductor Products Department, “A Low
`Cost, Ultrasonic Frequency Inverter using a Single
`SCR,” Note 20049, Neville Mapham, F611, 1967.
`-
`.
`n
`-
`-
`Envffonmental/‘me’ Annual Report’ Llcensmg Bus"
`“555 -
`IEEE Transactions on Industry Applications, “The
`
`1
`
`_ APPLE 1019
`
`1
`
`APPLE 1019
`
`

`

`Page 2
`
`4,308,443
`
`Induction Range: Its Performance and Its Development
`Problems”, W. C. Moreland II, Jan/Feb, 1973, vol.
`1A—9, No. 1.
`IEEE Transactions on Industry Applications, “A Por-
`table Cool—Surface Induction Cooking Appliances”,
`Philiph, Peters, Nov/Dec. 1974, vol.
`lA—lO, No. 6.
`“Induction Range Circuits-Past, Present, Future”, Jul.
`30, 1973.
`“Non—Heating Range Using Induction Method”, Mit-
`subishi Electric Corp.
`RCA, Solid State Division, Thyristors and Rectifiers
`“Characteristics and Applications of RCA Fast—S—
`witching ASCR’s”, Application note AN6456, Henri
`Digneffe, Jan. 1976.
`“Solid State Power Control Program”, Dr. Richard G.
`Hoft, Aug. 21, 1973.
`
`Primary Examiner—Gene Z. Rubinson
`Assistant Examiner—Philip H. Leung
`Attorney, Agent, or Firm—Richards, Harris & Medlock
`
`[57]
`
`ABSTRACT
`
`An induction heating system (40) is provided and in-
`cludes a plurality of induction heating coils (118).
`Touch control pads (50, 52, 70, and 72) are provided
`together with circuitry (80) for generating energization
`, control signals. Circuitry (112 and 116) is provided for
`electrically energizing the induction heating coils (118).
`An electronic digital processor (82) is responsive to the
`energization control signals for generating energization
`signals for actuating and controlling the energization
`circuitry (112 and 116) to thereby vary the energization
`of the plurality of induction heating coils (118). Cir-
`cuitry (150 and 152) is provided for maintaining touch
`control pads (50, 52, 70 and 72) operable when an opera-
`tor is in contact with a pan disposed adjacent the plural-
`ity of induction heating coils (118).
`
`13 Claims, 24 Drawing Figures
`
`2
`
`

`

`US. Patent
`
`Dec. 29, 1981
`
`Sheet 1 of 22
`
`4,308,443
`
`
`
`
`
`
`
`
`
`
`3
`
`

`

`US. Patent
`
`Dec. 29, 1981
`
`Sheet-2 of 22
`
`4,308,443
`
`
`
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`

`US. Patent
`
`Dec. 29, 1981
`
`Sheet 4 of 22
`
`4,308,443
`
`DISPLAY A
`
`I
`
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`
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`
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`
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`
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`
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`t” 282
`284 " & I». >80
`l-
`= 134
`DISPLAY BLANKING
`
`6
`
`

`

`U.S. Patent
`
`Sheet 5 of 22
`
`4,308,443
`
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`

`

`US. Patent
`
`Sheet 6 01°22
`Dec. 29, 1981
`
`
`4,308,443
`
`454
`
`
`
`
`
`Fig, ?
`
`464
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`US. Patent
`
`Dec. 29, 1981
`
`Sheet 7 of 22
`
`4,308,443
`
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`
`

`

`US. Patent
`>
`+
`
`Dec. 29, 1981
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`US. Patent
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`1
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`4,308,443
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`

`US. Patent
`
`Dec. 29, 1981
`
`Sheet 10 of 22
`
`4,308,443
`
`TIMER INTERRUPT
`
`
`
`STACK
`MAINTANENCE
`
`700
`
`
`
`702
`
`INCREMENT ICT'
`
`I
`
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`
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`
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`=0
`
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`
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`
`FIG. ll
`
`12
`
`12
`
`

`

`US. Patent
`
`Dec. 29, 1981
`
`Sheet 11 of 22
`
`4,308,443
`
`7/0
`
`CLOCK
`
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`
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`
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`BH‘=I
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`
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`
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`FIG. 12
`
`13
`
`13
`
`

`

`US. Patent
`
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`4,308,443
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`US. Patent
`
`Dec. 29, 1981
`
`Sheet 13 0122
`
`4,308,443
`
`826
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`
`15
`
`

`

`US. Patent
`
`Dec. 29, 1981
`
`Sheet 14 of 22
`
`4,308,443
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`(\l—
`to
`NN
`(In:
`
`NZhum
`
`16
`
`16
`
`
`
`
`
`
`
`
`
`
`
`

`

`US. Patent
`
`Dec. 29, 1981
`
`Sheet 15 of 22
`
`4,308,443
`
`672
`
`855%.?8”
`ROUHNE
`
`
`
`994
`
`6/
`
`SET
`R40=O
`SET
`
`‘ A COUNT=O
`
`.956
`
`Y
`
`a COUNT
`
`972
`
`980
`
`N
`
`INCREMENT
`
`958
`Y
`
`964
`
`
`983
`
`
`
`Y
`
`SET
`R41=o
`U)m_{
`B COUNT=O
`
`974
`
`~
`
`982
`
`R42
`
`990
`
`998
`
`Y
`
`SET _
`C COUNT=O
`
`I514“
`
`V
`;
`
`’
`
`.
`
`
`
`
`
`
`
`
`976
`
`SCAN LOCK 81
`UNLOCK PADS
`ROUTINE
`
`960
`Y
`
`~
`
`.984
`
`,
`
`SET R43=O
`
`R43
`
`Y
`
`
`
`
`1000
`
`992
`
`Y
`
`SET
`R43=O
`SET
`
`‘ D COUNT=O
`
`SET R8=O
`
`970
`
`FIG. 16
`
`17
`
`17
`
`

`

`US. Patent
`
`4,308,443
`
`Dec. 29, 1981
`40 SEC TURN OFF f
`ROUTINE
`
`
`
`CLEAR BITS 4 BI 5
`OF I/O PORT 4 BY
`WRITING A O
`
`READ PORT 4
`
`SHIFT RIHT
`4 PLACES
`
`SET BITS
`283 TO ZERO
`
`.
`
`;
`
`1
`
`1002
`
`I004
`
`1006
`
`10/2
`
`Sheet 16 of 22
`674
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`[0/0
`
`BITO 0R1
`=1
`
`
`
`Y
`
`STORE LOCK
`IN R30
`
`
`
`SET UPPER 5 BITS
`
`OF RII =OOIOI
`"OR” WITH
`
`FAN BIT
`
`
`SET BI
` T 6 OF
`PORT
`4 =RESULT
`
`
`[034
`
`
`
`
`
`
`DISABLE UP CMDS
`
`
`BY SETTING BIT]
`
`OF R30 TO I
`
`
`
`
`SET BIT 0 OF
`R30 TO I
`
`N
`
`
`
`FIG; 17
`
`18
`
`18
`
`

`

`US. Patent
`
`Dec. 29, 1981
`
`Sheet 17 of 22
`
`4,308,443
`
`Y
`
`'
`
`a
`N
`
`
`
`UPPER_OBITS
`
`pom
`O
`
`682
`
`1050
`
`1052
`
`1054
`
`1056
`
`1082
`
`1
`
`Y
`
`a
`
`1074
`1056
`N DECREMENT
`5
`
`A COUNT
`
`
`SET MUX
`
`w
`
`[060
`
`1068
`
`1076
`
`1084
`
`COSNT
`N DECREMENT
`»
`
`
`a :0
`B COUNT
`
`1070
`10 78
`
`Y
`
`062
`
`SET MUX
`
`1086
`
`READ PORT 0
`
`Y
`
`M
`
`N DECREMENT
`
`‘
`
`SET MUX
`
`‘
`
`
`
`C COUNT
`
`
`READ PORT 0
`
`,064
`
`1072
`
`1080
`
`1088
`
`Y
`
`®.@ D COUNT
`
`N
`
`DECREMENT
`
`SET MUX
`
`FIG. 18
`
`19
`
`19
`
`

`

`US. Patent
`
`Dec. 29, 1981
`
`‘
`
`Sheet 18 0f22
`
`4,308,443
`
`SCAN DOWN
`
`/ '
`
`; 686
`
`IIOO
`
`/ 694
`
`ELEMENTS ROUTINE ;;
`
`N
`
`~
`
`FLASH ACTIVE
`
`’
`
`i
`
`1/02”
`
`_
`
`690
`
`~
`
`
`ELEMENT ROUTINE
`
`
`
`4
`
`“08
`N
`
`“,0
`ACOUNT
`
`m2
`
`[1/8
`N ACOUNT=
`
`11/6
`,
`
`
`
`_ “06
`— -'
`‘
`1108
`1110
`
`SET
`ACOUNT-IOO’
`-
`1118
`
`‘
`
`1/14
`
`1116
`
`1/12
`
`
`
`N
`
`BCOUNT
`
`~
`
`N BCOUNT;
`
`_3
`'
`
`1108
`
`1/10
`
`1/12
`
`BCOUNHOO
`
`1/14
`
`11/8
`
`1116
`
`N
`
`CCOUNT
`
`N CCOUNT=
`
`,.Y
`
`[/06
`
`READ PORT O
`E
`
`‘4
`
`‘3
`“
`1108
`/
`
`11/0
`
`”/2
`
`N
`
`DCOUNT
`
`¢ ¢
`Y
`
`"
`
`C COUNT=IOO
`
`1118
`
`1114
`1116
`
`N DCOUNT:
`
`,
`
`-DCOUNT=IOO
`
`1114
`
`HG- 19
`
`692
`
`20
`
`
`
`20
`
`

`

`US. Patent
`
`Dec. 29, 1981
`
`Sheet 19 of 22
`
`4,308,443
`
`
`
`690
`
`688
`
`
`VERIFY SELECTED
`ELEMENT SETTING
`ROUTINE
`
`
`SCAN UF’ RADS
`ROUTINE
`
`
`
`
`SCAN FOR TURN OFF
`COMMANDS ROUTINE
`
`F/G. 20
`
`CLOCK SETTING
`ROUTINE
`
`21
`
`21
`
`

`

`US. Patent
`
`Dec. 29, 1981
`
`Sheet 20 of 22
`
`4,308,443
`
`222222 '
`ROUTINE
`_
`
`4
`
`692
`
`682
`
`H82
`
`I 186
`
`'7
`SET CLOCK
`CTIVE = l
`
`7/90
`
`1/92
`
`INCREM T
`MINUTES UNITS
`
`,
`;
`
`
`
`
`[/96
`
`ET MINUTES
`UNITS =0
`
`‘
`1
`
`SET HOURS’=I
`HOURS UNITS=1
`HOURS TENS =0
`
`
`
`
`1/94 4‘Eflfl¥fi§’>
`
`
`“‘EEEE§"’
`
`;
`f_;
`SET MINUTES
`
`
`I200
`
`1202
`
`FiG: 22
`
`N
`
`SET HOURS
`TENS=I
`
`-
`
`HOURS — IO
`
`STORE IN
`HOURS UNITS
`
`
`
`;
`;
`
`22
`
`22
`
`

`

`U.S. Patent
`
`Dec. 29, 1981
`
`Sheet 21 of 22
`
`4,308,443
`
`684
`
`
`
`CLOCK SETTING
`ROUTINE
`
`‘
`
`SCAN UP PADS
`ROUTINE
`
`688
`
`12.36
`
`
`
`1232
`
`I
`
`B COUNT
`
`
`
`1234
`
`1232
`
`I236
`
`
`
`FETCH D COUNT
`
`1234
`
`1232
`
`1236
`
`BIT3 =0
`
`BIT 3 :1
`
`SET FLASH R20
`
`1240
`
`1248
`
`N
`
`STORE
`
`IN
`
`’250
`
`N
`
`1242
`
`FETCH R8
`
`I244
`
`COMPLEMENT
`
`1246
`
`AND WITH R20
`
`’252
`
`SET FAN BIT =0
`
`658
`
`DISABLE
`INTERRUPTS
`
`'
`
`:
`
`FIG. 23
`
`23
`
`23
`
`

`

`US. Patent
`
`Dec. 29, 1981
`
`Sheet 22 of 22
`
`4,308,443
`
`STACK
`MAINTANENCE
`
`I
`
`'
`
`I
`
`[260
`
`1262
`
`
`1270 ® Y
`Y
`1254
`
`- -l»
`
`
`
` AND WITH PORT 4
`
`
`
`
`
`
`
`
`N
`
`COMPLEMENT
`
`RESULT
`
`SET UPPER BITS :0
`AND STORE IN RIO ,
`
`SET BITS 48x 5 =0
`
`COMPLEMENT
`
`
`EXCLUSIVE OR
`WITH INTERRUPT
`
`SOURCES
`STORE IN
`INTERRUPT SOURCES
`
`
`
`I310
`
`13/2
`
`SET PORT 4
`BIT 7 =0
`
`WAIT 3OMSEC
`
`SET PORT 4
`BIT 7 =1
`
`COUNT=O
`
`., SET c
`COUNT=O
`
`7 SET 8
`COUNT=O
`
`/
`
`
`
`;
`
`‘
`:
`
`1
`
`SETA
`COUNT=O
`
`.
`
`FETCH MUX
`
`COMPLEMENT
`
`i
`
`1278
`
`I280
`
`AND WITH
`PORT 4
`
`~
`OUTPUT TO
`PORT 4
`
`‘
`
`’23?
`
`[284
`
`I
`5
`
`I
`
`'
`
`AND PORT 4
`
`LOWER BITS
`WITH PORT 5
`LOWER BITS
`
`
`1285
`
`FIG 24
`.
`
`-‘
`MAINTANENCE
`
`PREVIOUS
`ROUTINE POSITION
`
`[3/6
`
`24
`
`24
`
`

`

`I
`
`4,308,443
`
`INDUCTION COOK-TOP WITH IMPROVED
`TOUCH CONTROL
`
`RELATED APPLICATIONS
`
`This application is an improvement of co-pending
`U.S. patent application Ser. No. 819,164, filed July 26,
`1977, U.S. Pat. No. 4,169,222, and entitled “Induction
`Cook-Top System and Control” and U.S. patent appli-
`cation Ser. No. 819,169, filed July 26, 1977, U.S. Pat.
`No. 4,149,217, and entitled “Touch Control Panel For
`Induction Heating Cook-Top.”
`TECHNICAL FIELD
`
`This invention relates to cook systems, and more
`particularly relates to an induction cook-top system.
`BACKGROUND ART
`
`10
`
`.
`
`15
`
`20
`
`30
`
`35
`
`The basic principles of induction heating have been
`known for quite some time. It has heretofore been
`known to utilize power sources including rectifiers and
`inverters -in order to drive an induction heating coil,
`thereby producing an alternating magnetic field which
`is coupled through a planar cooling surface to a cooking
`pan in order to provide cooking action. Examples of 25
`such previously developed induction cooking systems
`may be found in U.S Pat. No. 3,637,970 issued to Cun-
`ningham on Jan. 25, 1972 and entitled “Induction Heat-
`ing Apparatus”; U.S. Pat. No. 3,697,716 issued to Korn-
`rumpf on Oct. 10, 1972 and entitled “Induction Cooking
`Power Converter with Improved Coil Position” and
`U.S. Pat. No. 3,823,297 issued to Cunningham on July 9,
`1974 and entitled “Load Controlled Induction Heat-
`ing”. It has also been known to utilize touch control
`devices to control the operation of such induction cook-
`ing devices.
`Previously developed induction cook-top devices
`have not provided adequate control systems for con-
`trolling the energization, deenergization, and variation
`of heating levels of induction heating coils. Lack of 40
`such control introduces unsafe operating conditions in
`the use of induction cook-top devices. For example, one
`such unsafe operating characteristic observed in prior
`art induction cook-top devices has been the inability to
`decrease a heating level of an induction heating coil
`when the induction heating coil is operating at a high
`level and the operator is in physical contact with the
`cooking pan or a utensil, such as a spoon, inside the
`cooking pan. The operator must therefore remember
`not to touch the cooking pan or a utensil in order to
`decrease the heating level or shut off an induction heat-
`ing coil. This operating requirement makes the opera-
`tion of induction cooking devices cumbersome and
`hazardous. Consequently, a need has arisen for an in-
`duction cook-top system which is economical to manu-
`facture and simple in operation, including touch con-
`trols that are accurate to safely control heating levels
`and energization of the system.
`DISCLOSURE OF THE INVENTION
`
`45
`
`50
`
`55
`
`60
`
`In accordance with the present invention, an induc-
`tion cook-top system is provided which substantially
`eliminates or reduces the problems heretofore present in
`prior multi-coil
`induction cook—tops utilizing touch
`control systems and visual displays.
`In accordance with the present invention in an induc-
`tion cooking system a plurality of induction heating
`coils is provided. Circuitry is provided for electrically
`
`65
`
`2
`energizing the plurality of induction heating coils. Con-
`trols are provided for generating energization control
`signals. Circuitry is further provided being responsive
`to the energization control signals generated by the
`controls for generating energization signals. The energi-
`zation signal actuate and control the energization cir-
`cuitry to thereby vary the energization of the plurality
`of induction heating coils. Circuitry is provided for
`maintaining the controls operable when an operator is
`in contact with a pan disposed adjacent the plurality of
`induction heating coils. Circuitry is further provided for
`reducing the voltage stress on the energization circuitry
`without changing the normal operating voltage levels
`of the energization circuitry.
`
`BRIEF DESCRIPTION OF DRAWINGS
`
`For a more complete understanding of the present
`invention and. for
`further objects and advantages
`thereof, reference is now made to the following De-
`tailed Description taken in conjunction with the accom-
`panying Drawings in which:
`FIG. 1 is a perspective top view of an induction cook-
`top utilizing a touch control panel according to the
`present invention;
`FIG. 21s a top plan view of the touch control panel
`of the present invention shown1n FIG. 1;
`FIG. 3 is an electrical block diagram of the electrical
`control and logic circuitry of the touch control panel of
`the present invention;
`FIG. 4 is a detailed schematic diagram of the touch
`pads and touch input circuit shown in the block diagram
`of FIG. 3;
`FIG. 5 is a detailed schematic diagram of the micro-
`processor and related circuitry shown in the block dia-
`gram of FIG. 3;
`FIG. 6IS a detailed schematic diagram of the pan and
`temperature sensors shown in the block diagram of
`FIG. 3;
`FIG. 7 is a detailed schematic diagram illustrating the
`power drivers shown in the block diagram of FIG. 3;
`FIG. 8 is a detailed schematic diagram of the inverter
`and induction heating coil circuitry shown in the block
`diagram of FIG. 3;
`FIG. 91s a detailed schematic diagram illustrating the
`display and display drivers shown1n the block diagram
`of FIG. 3;
`FIG. 1015 a software flow diagram of the basic sys-
`tem program for the microprocessor shown1n the block
`diagram of FIG. 3,
`1"
`FIG. 11 is a software flow diagram of the Timer
`Interrupt Routine;
`FIG. 12 is a software flow diagram of the Display
`Routine;
`FIG. 13 is a software flow diagram of the Gate Pulse
`Routine;
`FIG. 14 is a software flow diagram of the Clock
`Routine;
`FIG. 15 is a software flow diagram of the Display
`Digit Processing Routine;
`FIG. 16 is a software flow diagram of the Forty Sec-
`ond Turnoff Routine;
`FIG. 17 is a software flow diagram of the Scan Lock
`and Unlock Pads Routine;
`FIG. 18 is a software flow diagram of the Scan Down
`Pads Routine,
`FIG. 191s a software flow diagram of the Scan Up
`Pads Routine;
`
`25
`
`25
`
`

`

`4,308,443
`
`3
`FIG. 20 is a software flow diagram of the Verify
`Selected Element Setting Routine;
`FIG. 21 is a software flow diagram of the Scan For
`Turnoff Commands Routine;
`FIG. 22 is a software flow diagram of the Clock
`Setting Routine;
`FIG. 23 is a software flow diagram of the Flash Ac-
`tive Elements Routine; and
`FIG. 24 is a software flow diagram of the External
`Interrupt Routine.
`DETAILED DESCRIPTION
`
`Referring to FIG. 1, a perspective top view of an
`induction cook-top surface is illustrated and is generally
`identified by the numeral 40. Cook-top surface 40 in-
`cludes a rectangular planar surface 42 having four cook-
`ing units or areas identified as A, B, C and D provided
`thereon. Cooking areas A and C are smaller than cook-
`ing areas B and D in order to enable the accommodation
`of different size cooking pans. Surface 42 comprises a
`suitable ceramic or other material able to withstand
`high temperatures. Circular patterned indicia are
`formed in surface 42 to denote cooking areas A, B, C
`and D which are above four induction heating coils, not
`shown in FIG. 1, and which are located beneath surface
`42.
`
`Surface 42 is maintained in place within a conven-
`tional kitchen counter 44 by a stainless steel mounting
`rim 46. A touch control panel of cook-top surface 40 is
`generally identified by the numeral 48 and includes
`touch control areas or pads 56 associated with each
`cooking area A-D. Touch control pads 56 provide con-
`trol of cooking areas A-D when the operator places a
`finger in contact with a designated surface of touch
`control pads 56. Touch control pads 56 illustrated in
`FIG. 1 comprise merely indicia formed on a glass plate
`57 and do not require physical depression by the opera-
`tor.
`‘
`
`Referring simultaneously to FIGS. 1 and 2, touch
`control panel 48 includes a LOCK TOUCH CON-
`TROL PAD 50 and an UNLOCK TOUCH CON-
`
`TROL PAD 52 provided at the upper portion of touch
`control panel 48. The operation of LOCK TOUCH
`CONTROL PAD 50 and UNLOCK TOUCH CON-
`TROL PAD 52 will be subsequently described. Associ-
`ated with each touch control pad 56 is a status display
`indicator 58, SSA—58D, to provide a visual indication
`when one or more cooking areas A—D are energized.
`Touch control panel 48 further includes a display gener-
`ally identified by the numeral 60 for alternately display-
`ing a visual indication of the desired power to be deliv-
`ered to each of the cooking aread A-D. A representa-
`tion of the cooking power desired is displayed in display
`62 while the letter of the corresponding cooking area
`A-D is illustrated in display 64.
`Touch control pads 56 each include a HI TOUCH
`CONTROL PAD 70, 70A—70D, and a LOW TOUCH
`CONTROL PAD 72, 72A-72D, which may be touched
`by the operator in order to set the heat indicator at a
`desired level. Touch control pads 56 further include an
`OFF TOUCH CONTROL PAD 74, 74A~74D, which
`may be touched by the operator in order to shut the
`associated cooking area A-D off. OFF TOUCH CON~
`TROL PAD 74 is disposed between HI TOUCH CON-
`TROL PAD 70 and LOW TOUCH CONTROL PAD
`72, such that the finger of an operator when in contact
`with OFF TOUCH CONTROL PAD 74 bridges the
`area between HI TOUCH CONTROL PAD 70 and
`
`4
`LOW TOUCH CONTROL PAD 72 to simultaneously
`touch both HI TOUCH CONTROL PAD 70 and
`LOW TOUCH CONTROL PAD 72.
`
`In operation of induction cook-top surface 40, touch
`control pads 56 are initially locked in an off- condition.
`The operator’s finger is, initially placed on the UN-
`LOCK TOUCH CONTROL PAD 52 to enable opera-
`tion of touch control pads 56. The operator may then
`turn on a cooking area A—D by touching a HI TOUCH
`CONTROL PAD 70. As soon as a HI TOUCH CON-
`TROL PAD 70 is touched, the corresponding status
`display indicator 58 is illuminated to indicate that a
`cooking area has been selected.
`For example, if an operator desires to turn on cooking
`area A, HI TOUCH CONTROL PAD 70A is lightly
`touched with one finger by the operator. No pressure or
`depression by the finger of the operator is required. The
`display 64 displays the letter “A” to indicate that cook-
`ing area A is actuated. Display 62 will display in incre—
`ments of ten the relative cooking power delivered to, the
`cooking area A until 100 is reached. The percentage of
`the total power available for cooking area A will con-
`tinue to increase depending upon the length of time the
`operator’s finger is held on HI TOUCH CONTROL
`PAD 70A until 100 is reached, as illustrated in FIG. 2.
`The displayed power percentage rises at a relatively fast
`rate when a HI TOUCH CONTROL PAD 70 is
`touched.
`
`To adjust the heat setting of a cooking area A-D, the
`LOW TOUCH CONTROL PADS 72 are utilized. The
`amount of power applied to a cooking area A-D will
`decrease as long as the operator’s finger is held on LOW
`TOUCH CONTROL PAD 72A until display 62 indi-
`cates a 0. The rate of decrease in power to a cooking
`area is at a much slower rate, in increments of one, than
`the increase rate of ten controlled by HI TOUCH
`CONTROL PAD 70, thus enabling a very accurate
`setting of the desired cooking power level. If the opera-
`tor desires to again raise the temperature of cooking
`area A,
`it will be necessary to touch UNLOCK
`TOUCH CONTROL PAD 52.
`The heat applied to each cooking area B-D may be
`regulated in a similar manner by touching touch control
`pads 56B—56D of the respective positions of touch con-
`trol panel 48.
`In order to turn a cooking unit completely off, the
`operator touches both the HI TOUCH CONTROL
`PAD 70 and the LOW TOUCH CONTROL PAD 72
`
`for a cooking area A-D at the same time by placing a
`finger on each pad. The cooking area will be immedi-
`ately turned off and the status display indicator 58 will
`be extinguished. The display 64 will indicate the cook-
`ing area A-D previously actuated and display 62 will
`illustrate a 0. If none of the other cooking areas are on,
`display 60 will indicate the time of day.
`The use of LOCK TOUCH CONTROL PAD 50
`will cause all touch control pads 56 to be locked for a
`predetermined time, such as for five seconds, and each
`cooking area A-D will remain at its heat level setting at
`the time LOCK TOUCH CONTROL PAD 50 was
`
`touching any of touch control
`touched. Thereafter,
`pads 56 will have no effect on heating levels as long as
`induction cook-top surface 40 is in the locked mode. In
`order to restore operation from the locked mode before
`the predetermined locked time has elapsed, the operator
`merely touches UNLOCK TOUCH CONTROL PAD
`52. UNLOCK TOUCH CONTROL PAD 52 must be
`
`touched before any cooking area A—D can be turned on
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`60
`
`65
`
`26
`
`26
`
`

`

`4,308,443
`
`5
`or the power level setting of a cooking area A-D in-
`creased. While any of the cooking areas A-D are on,
`holding the operator’s finger on LOCK TOUCH CON-
`TROL PAD 50 for a predetermined time will cause
`display 60 to indicate the time of day and touch control
`pads 56 will be inoperative. After a predetermined time
`after the operator’s finger is removed from LOCK
`TOUCH CONTROL PAD 50, display 60 will revert to
`display the cooking area A-D in display 62 and the
`relative percent of heat applied to the cooking area A-D
`in display 62.
`Touch control panel 48 provides numerous safety
`features. Cook-top surface 40 is automatically locked in
`the off position when power is initially applied to cook-
`top surface 40 and cook-top surface 40 cannot be oper-
`ated unless UNLOCK TOUCH CONTROL PAD 52 is
`touched. When cook-top surface 40 is turned on by
`holding of a finger on UNLOCK TOUCH CONTROL
`PAD 52, a cooking area A-D must be turned on within
`a predetermined time period, such as five seconds, or
`cook-top surface 40 and touch control pads 56 will
`automatically turn off. Each of cooking areas A-D may
`be turned off immediately by touching both HI and
`LOW TOUCH CONTROL PADS 70 and 72 associ-
`ated with a cooking area A—D simultaneously. Due to
`the present inductive heating design, heat is immedi-
`ately extinguished and cook-top surface 40 does not
`retain heat which could cause serious burns to the oper-
`ator.
`
`As will subsequently be described, cooking areas
`A-D will not operate unless a proper cooking pan is
`placed on the cooking area A-D. If the cooking area
`A-D is turned on with an improper pan or with no pan
`on the cooking area A-D, status display indicator 58 for
`that cooking area will flash for a predetermined time,
`such as forty seconds, or until the proper pan is put on
`the cooking area A-D. During the flashing of status
`display indicator 58, no heat1s generated from the cook-
`ing area A-D. If a pan is removed from the cooking area
`A-D during the cooking operation, the cooking area
`A-D will automatically terminate heating and the status
`display indicator 58 will flash. If the pan is returned to
`the cooking area A-D within a’ predetermined time
`period after removal, heating will resume in that cook-
`ing area. Otherwise, at the end of this predetermined
`time period, the cooking area A-D will return to the off
`state and status display indicator 58 will be extin-
`guished.
`Each cooking area A—D is equipped with a sensor
`which will turn the cooking area A-D off if a maximum
`level of operating temperature is exceeded, such as
`would occur if a cooking pan boiled dry.
`.Touch control panel 48 is constructed to minimize
`fabrication expense while providing ease of mainte-
`nance. Such a control panel is described in co-pending
`US. patent application Ser. No. 810,169 filed July 26,
`1977 and entitled “Touch Control Panel for Induction
`Heating Cook-top” and assigned to the assignee of the
`present invention FIG. 3 illustrates a block diagram of
`the electrical circuitry of the present touch control
`panel 48. Touch control panel 48 includes HI and LOW
`TOUCH CONTROL PADS 70, 72, LOCK TOUCH
`CONTROL PAD 50 and UNLOCK TOUCH CON-
`TROL PAD 52. Touch control pads 70,72, 50 and 52
`are interconnected to touch input circuit 80 which
`senses that a touch control pad 70, 72, 50 and 52 has
`been touched by an operator. Touch input circuit 80
`senses which of touch control pads 70, 72, 50 and 52
`
`6
`have been touched and provides energization control
`signals for cooking areas A-D to a microprocessor cir-
`cuit 82 via signal lines 84, 86, 88 and 90. Logic signals
`are also applied to microprocessor circuit 82 from tem-
`perature sensors generally identified by the numeral 92
`via signal lines 94 and pan sensors generally identified
`by the numeral 96 via signal lines 98 located adjacent
`each_ of the cooking areas A-D. Microprocessor circuit
`82 also receives the input from an oscillator 100 via a
`signal line 102.
`Microprocessor circuit 82 generates energization
`I signals for cooking areas A-D and applies these energi—
`z'ation signals via signal lines 110 to power drivers 112
`'which generate selected electrical power
`signals
`through transformers generally identified by the nu-
`meral 114 to inverters 116. The outputs of inverters 116
`are applied to the designated one of four induction
`heating coils generally identified by the numeral 118,
`one each for cooking areas A—D. Induction heating coils
`118 are located beneath surface 42 of induction cook-
`top surface 40 in the vicinity of cooking areas A-D.
`AC voltage is applied from a power source 122 to a
`DC power supply 124 whose output is applied to invert-
`ers 116 in the manner to be subsequently described.
`Circuitry associated with power drivers 112 senses the
`zero voltage potential crossing of the AC voltage po-
`tential and generates the ZERO VOLTAGE CROSS-
`ING signal applied along signal
`line 126 to micro-
`processor circuit 82. The function of the ZERO VOLT-
`AGE CROSSING signal will be subsequently de-
`scribed.
`.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`An output of microprocessor circuit 82 is applied
`along signal line 128 to fan driver 130 for operating a fan
`132 located within the interior of induction cook-top
`surface 40 to provide cooling. Fan 132 operates when
`UNLOCK TOUCH CONTROL PAD 52 is touched
`and is deactivated after all cooking areas A-D have
`been turned off.
`
`Microprocessor circuit 82 also generates via signal
`lines 134 output signals to display drivers 136 which
`generate signals via signal lines 138 to operate display
`60.
`
`AC power is also a