Titan-2000-pwr-sm 维修电路原理图.pdf

Elektor Electronics2/99It could be arguedthat most of the out-put amplifiers pub-lished in this maga-zine lack power.Although this is adebatable point, itwas felt that a trueheavyweight outputamplifier would makea welcome change formany constructors.The Titan 2000 canproduce 300 wattsinto 8 , 500 wattsinto 4 , and800 watts into 2 .For those who believethat music power is areputable quantity, theamplifier can deliver2000 watts of thismagical power into4 .58Design by T. Giesberts Titan 2000High-power hi-fi andpublic-address amplifierBrief parametersSine-wave power output300 W into 8 ; 500 W into 4 ; 800 W into 2 Music power*2000 W into 4 Harmonic distortion on the amplifier board)via K1.The terminals marked temp areintended to be linked to the output ofthe fan control circuit.As mentioned earlier, the action ofeach sensor results in the deenergizingof the output and mute relays in theamplifiers. This implies that the out-puts of the the various sensor circuitsare interlinked. This is effected by com-bining the open-collector outputs ofthese circuits into a wired OR gate withR12functioning as the common pull-up resistance. The combined outputsignal serves to reset a number of34Elektor Electronics3/99990001-2(C) ELEKTORB1C1C2C3C4C5C6C7C8C9C10C11C12C13C14C15C16C17C18C19C20C21C22C23C24C25C26D1D2D3D4D5D6D7D8D9D10D11D12D13F1H1H2H3H4H5H6H7H8IC1IC2IC3IC4IC5IC6IC7IC8IC9JP1K1K2K3K4P1P2P3R1R2R3R4R5R6R7R8R9R10R11R12R13R14R15R16R17R18R19R20R21R22R23R24R25R26R27R28R29R30R31R32R33R34R35R36T1T2T3T4T5T6TR150mAT0+12V-12VintextVre00LSPinputT+IT+5VtempTmute2R-12V+12V0+5V990001-2990001-2(C) ELEKTORParts listsProtection networkResistors:R1, R33, R34= 100 kR2= 1.05 kR3, R4= 10.0 kR5= 680 R6= 820 kR7= 1 MR8, R11, R18, R19, R24, R25, R29= 47 kR9, R10= 470 R12, R21, R22= 2.2 kR13= 470 kR14= 2.2 MR15, R17= 1 kR16, R23, R26, R27= 4.7 kR20= 2.7 MR28= 3.9 kR30, R35= 3.3 kR31, R32= 15 kR36= 22 P1= 250 , multiturn preset (upright)P2= 500 , multitun preset (upright)P3= 500 k, multiturn preset (upright)Capacitors:C1, C3= 0.1 FC2= 0.001 FC4, C5, C6, C8, C12C17=0.1 F,ceramicC7= 0.47 FC9, C18, C19, C22= 4.7 F, 63 V, radialC10= 10 F, 63 V, radialC11, C23= 47 F, 25 V, radialC20= 1000 F, 25 V, radialC21= 470 F, 25 V, radialC24C26= 0.047 F, ceramicSemiconductors:D1, D2= BAT82D3, D4= BAS45AD5, D7= 1N4148D6, D8, D9, D13= 3 mm high-efficiencyLED (yellow, red, green, green respectively)D10, D11= 1N4007D12= 1N4001T1, T3, T5, T6= BC547BT2, T4= BD140Integrated circuits:IC1= OP249GP (Analog Devices)IC2= LM319NIC3= 74HC4060IC4= 74HC175IC5, IC6= 4N35IC7= 7812IC8= 7912IC9= 7805Miscellaneous:JP1= 2.54 mm pin strip and pin jumperK1, K2= 3-way terminal block, pitch5 mmK3= 2-way terminal block, pitch 5 mmK4= 2-way terminal block, pitch 7.5 mmB1= bridge rectifier, rectangular, TypeB80C1500F1= fuse, 50 mAT and fuse holderTr1= mains transformer, 15 VA, with215 V secondaryHeat sink (for IC7) = e.g. FischerSK104, 50 mmMains interference filterFigure 5. The printed-circuitboard of the overall protec-tion network.ContentsD-type bistables (flip-flops), contained inIC4, which are inter-connected to form ashift register. Note that D-type bistablesare essential since these can be set andreset in a defined manner.The outputs of IC4are used to drivetwo level converters, T1-T2and T3-T4respectively, which bridge the differ-ence between the 5 V level of the logicICs and the 12 V supply for the relays.Jumper JP1enables a different, externalsupply voltage (VRE) to be used if 12 Vrelays are not employed.Transistors T1and T2drive Re1andRe2, which are the first to be energized(synchronously). On switch-off, capac-itor C9ensures that T2remains on forsome milliseconds longer duringwhich period Re3and Re4are deener-gized (see Part 1).The power-on delay, which alsooperates after a fault situation, is morecomplex than usual. To start with, afterthe supply voltage us switched on,input CLR of IC4is held low (active)for a few seconds by the circuit aroundT6. When, after this period, CLR ismade high by R12which happensonly when there is no error situation(any longer)the internal oscillator ofIC3is enabled via D5. This results aftera few seconds in a clock pulse appear-ing at the CLK input of IC4, where-upon Q4goes high. The periodbetween the oscillator being enabledand the appearance ofthe first clock pulse isnot defined since,owing to the presenceof T6, a power-on reset is purposely notprovided. To ensure a minimum delayin the energizing of Re1and Re2inspite of this, a high level is clocked intoQ4after IC3has been enabled. The pre-cise moment at which this happensvaries, therefore, only when the supplyvoltage is switched on for the first time.A period of IC3/Q3later, Q1of IC4goes high, whereupon Re1and Re2areenergized. After another period, Q2ofIC4becomes high, whereupon Re3andRe4are energized. At the same time,IC3is disabled since its reset is inter-linked with Q2 of IC4.The red LED, D8, in parallel with Q1of IC4lights when the relays in theamplifier are not energized, eitherbecause the amplifier is (not yet)switched on, or owing to an error. The yellow LED, D6, is linked to theoutput of the oscillator in IC3, causingit to flash until IC4is clocked.The green LED, D9, is connected inparallel with Re3and Re4, so that itlights only when the amplifier is fullyswitched on.T R A N S F O R M E RV O L T A G ES E N S O RThe 50 V secondary voltages of themains transformers in the amplifier arerectified by diodes D10and D11, andsmoothed by R30-R31-R32-C10. The val-ues of these components ensure thatthe LED in optoisolator IC6lights suf-ficiently to hold the associated phototransistor on. This transistor pulls thebase of T5to ground, causing T5to cutoff. When the secondary voltages fail,T5is switched on immediately via R29,whereupon the D-type bistables in IC4are reset.Use is made of an optoisolator pur-posely to avoid any risk of earth loopsbetween the supply return and theground of the protection network,which is linked to the input ground ofthe amplifier.T E M P E R A T U R ES E N S O RThe temperature sensor works in amanner similar to that of the trans-former voltage sensor. The optoisolatorin this circuit is IC5, which, in contrast toIC6, is normally cut off and comes ononly when the heat sink becomesexcessively hot.The sensor reacts to the fan controlcircuit switching the fan speed to max-imum (because the heat sink is gettingtoo hot). A comparator in the fan con-trol circuit then toggles, whereuponIC5is actuated via the temp input andresets the D-type bistables in IC4. Thissituation changes only after the heatsink has cooled down to an acceptabletemperature (although the fans maystill be rotating).C U R R E N TS E N S O RTo nullify high common-mode voltagesand to prevent any risk of earth loops,the current sensor also uses an optoiso-lator, IC2(Figure 5). However, this isnot located on the protection board,but directly at the output of the ampli-fier.The values of the relevant compo-nents cause the sensor to be actuatedwhen the output current is about 40 A.This may appear a very large current,but this is due entirely to the specifiedrequirement that the amplifier must becapable of delivering 60 V into a loadof 1.5 without the protection circuitbeing actuated. The current level maybe lowered to some extent by increas-ing the value of R74in the amplifier.Output resistor R78is in parallelwith R12by linking terminals I, +5 Vand ground on the amplifier board toK1on the protection board via threelengths of insulated, stranded circuitwire twisted together. This arrange-35Elektor Electronics3/99Figure 6. Completed pro-totype of the protectionnetwork.Contents37Elektor Electronics3/99ment ensures a low impedance to anyinterference and a high reaction speed.D I R E C T-C U R R E N TA N DO V E R D R I V ES E N S O RThe d.c. and overdrive sensor con-stantly compares the input and outputsignals of the amplifier and reactswhen the difference between the twois too great. The comparison is effectedwith the aid of operational amplifierIC1which has a very low bias currentand a very low offset. It is, of course,essential that during the comparison ofthe two signals by differential amplifierIC1bthe differences in phase and tran-sit times do not lead to error detection.At the same time, the voltage amplifi-cation (43) of the amplifier must betaken into account.The amplification is compensatedby potential divider R1-R2-P1at inputLSP . The potentiometer is a multiturntype to ensure accurate adjustment.The phase difference is compen-sated by the circuit based on IC1a. Thetransit at high and low cut-off pointsis simulated by first-order networksthat can also be adjusted very accu-rately with multiturn poten-tiometers P2and P3.The inputs of IC1aand IC1bare protected by diodes. Since anyleakage current of these diodes, com-bined with the high input impedance( 1 M) of IC1a, might lead to anappreciable offset, and therefore to anunwanted error detection, the diodes,D3and D4, are special types with aleakage current of only 1 nA.The output of differential amplifierIC1bis monitored by a window com-parator formed by IC2aand IC2b. Thevalue of the components used inpotential dividers R8-R9and R10-R11ensures that the protection circuit isactuated when the direct voltagereaches a level of 5V or the distortionbecomes 2.5 per cent. Such distortionwill normally be the result of over-drive, but the circuit reacts equally wellto oscillations or other spurious signalsthat cause too large a difference to bedetected.C O N S T R U C T I O NA N DS E T T I N GU PThe integrated protection network isbest built on the printed-circuit boardshown in Figure 5. Populating thisboard should not present any unduedifficulties, but it should be noted thatdiodes D6, D8, D9and D13, are notlocated on the board, but are linked toit via flexible, stranded circuit wire.They are fitted to the front of the enclo-sure.Jumper JP1will normally be in posi-tion intern unless relays with a coilvoltage other than 12 V are used.A prototype of the completed pro-tection board is shown in Figure 6.All input and output terminals ofthe board are clearly marked with thesame symbols as shown in Figure 4.Most interconnections can be made inthin, stranded hook-up wire toDEF61-12, but the input and outputlinks (input and LSP) must bescreened audio cable.Although the power supply for theprotection network can be fitted on thesame board, the relevant section maybe cut off and fitted elsewhere. Ofcourse, the supply lines must then belinked to the relevant terminals on theprotection board via insulated,stranded hook-up wire.The power supply is straightfor-ward. From the secondary output ofthe specified mains transformer, Tr1, asymmetrical 12 V supply is obtainedwith the aid of regulators IC7and IC8.From the same secondary, a +5 V sup-ply for the digital circuits is obtainedwith the aid of regulator IC9. Since therelays are fed by the +12 V line, regu-lator IC7must be fitted on a heat sink.To ensure that the protection net-work is not actuated by interference onthe mains supply, it is advisable to pre-cede the power supply by a suitablenoise filter. This may be made from a30 H choke and two 0.1 F, 300 Vcapacitors as shown in dashed lines inFigure 4.The network is set up by maximiz-ing the common-mode suppression(C) ELEKTOR990001-3C1C2C3C4D1D2D3D4D5D6D7D8F1F2H1H2H3H4K1K2K3K4R1R2TR1TR2990001-30-+0.16AT0.16AT(C) ELEKTOR990001-37Parts listsAuxiliary power supplyResistors:R1, R2= 1 MCapacitors:C1, C2= 470 F, 100 V, radialC3, C4= 0.1 F, 100 V, pitch 7.5 mmSemiconductors:D1D8= 1N4007Miscelleneous:K1= 2-way terminal block, pitch 7.5mmK2= 3-way terminal block, pitch7.5 mmK3, K4= 2-way terminal block, pitch5 mmTr1, Tr2= mains transformer, 1.5 VA,with 12 V secondartF1, F2= fuse, 160 mAT, and fuseholderFigure 7. Printed-circuit boardfor the auxiliary power supplydescribed in Part 1.Contents38Elektor Electronics3/99200V / 35A200V / 35A2x 50V500VA2x 50V500VA2A5 T2A5 T990001 - 2 - 1270V70V1000VA6x 22000 / 100Vmainspower-ondelaymainspower-ondelaye.g. 974078 - 1e.g. 974078 - 19with the aid of an oscilloscope or amultimeter with sufficient bandwidth.Measurements need to be made at1 kHz, 20 kHz, and 20 Hz. The open-circuit amplifier is driven as far as pos-sible by a suitable sine-wave generatoror CD player with a test CD.With a signal of 1 kHz, set P1forminimum sign al at the output of IC1b,follow this with a signal of 20 kHz andadjusting P2, and finally, with a signalof 20 Hz, by adjusting P3. Since the set-tings influence one another to someextent, the potentiometers should beset a couple of times, perhaps also atsome different audio frequencies.P O W E RS U P P L YThe auxiliary power supply describedin Part 1 is best constructed on theprinted-circuit board shown in Fig-ure 7. The mains voltage is linked toK1, the 70 V to K2and the +85 V and85 V lines to K3and K4respectively.Since all currents are low level, thewiring may be made in thin, insulated,stranded hook-up wire. A completedprototype board is shown in Figure 8.The main supply for the amplifier isa straightforward, unregulated type,providing an output of 70 V. Its cir-cuit diagram is shown in Figure 9.Since the specified requirementscall for a 2 load, the supply must berated at 1000 VA, which necessitatestwo toroidal transformers. To preventunforeseen equalizing currents, thedual secondaries are not linked in par-allel, but are individually connected toa bridge rectifier. The outputs of therectifiers can be connected in parallelwithout any problem. The rectifiersneed to be mounted on a suitable heatsink such as a Type SK01. It should be clear that the wiring ofthe power supply mustallow for the large out-put currents of theamplifier. In the proto-type, the electrolyticcapacitors are linked by 3 mm thickstrips of aluminium. The remainder ofthe wiring should be in insulated,high-current wire to BS6231 with aconductor size of 50/0.25 mm (2.5 mm2)or better. The use of car-type connec-tors is recommended.Note that the power supply asdescribed is intended for use with amono(phonic) ampli-fier that can deliver800 W into 2 andshould remain stablewith loads of 1.5 . Ifyou are certain that you will alwaysuse 4 or 8 loads, the power supplyrequirements may be relaxed to someextent. A reasonable relaxation is theuse of 250V/300VA transformers and10,000 F/100 V smoothing capacitors.The rating of the primary fuses maythen be reduced to 1.5 AT.M A I N S-O ND E L A YThe use of a mains-on delay is recom-mended when heavy loads are to beswitched on, as in the case of the pre-sent amplifier. Such a delay circuitswitches on the mains to the load grad-ually to ensure that the switch-on cur-rent remains within certain limits and toprevent the mains fuses from blowing. The most recently published (in thismagazine) mains-on delay is found inthe July/August 1997 issue (p. 74),whose circuit diagram is reproduced inFigure 10. Its printed-circuit board isreadily connected with the primarywindings of the two mains transform-ers. The board is not available ready-made, however, an