Titan-2000-pwr-sm维修电路原理图.pdf

Elektor Electronics2/99 It could be argued that most of the out- put amplifiers pub- lished in this maga- zine lack power. Although this is a debatable point, it was felt that a true heavyweight output amplifier would make a welcome change for many constructors. The Titan 2000 can produce 300 watts into 8 , 500 watts into 4 , and 800 watts into 2 . For those who believe that music power is a reputable quantity, the amplifier can deliver 2000 watts of this magical power into 4 . 58 Design by T. Giesberts Titan 2000 High-power hi-fi and public-address amplifier Brief parameters Sine-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 are intended to be linked to the output of the fan control circuit. As mentioned earlier, the action of each sensor results in the deenergizing of the output and mute relays in the amplifiers. This implies that the out- puts of the the various sensor circuits are interlinked. This is effected by com- bining the open-collector outputs of these circuits into a wired OR gate with R12functioning as the common pull- up resistance. The combined output signal serves to reset a number of 34 Elektor Electronics3/99 990001-2 (C) ELEKTOR B1 C1C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 C16 C17 C18 C19 C20 C21 C22 C23 C24 C25 C26 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 D13 F1 H1 H2 H3 H4 H5 H6 H7 H8 IC1 IC2 IC3 IC4 IC5 IC6 IC7 IC8 IC9 JP1 K1 K2 K3 K4 P1 P2 P3 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 R22 R23 R24 R25 R26 R27 R28 R29 R30 R31 R32 R33 R34 R35 R36 T1 T2 T3 T4 T5 T6 TR1 50mAT 0 +12V -12V intextVre0 0 LSP input T + IT +5V temp T mute 2R -12V+12V0+5V 990001-2 990001-2 (C) ELEKTOR Parts lists Protection network Resistors: R1, R33, R34= 100 k R2= 1.05 k R3, R4= 10.0 k R5= 680 R6= 820 k R7= 1 M R8, R11, R18, R19, R24, R25, R29= 47 k R9, R10= 470 R12, R21, R22= 2.2 k R13= 470 k R14= 2.2 M R15, R17= 1 k R16, R23, R26, R27= 4.7 k R20= 2.7 M R28= 3.9 k R30, R35= 3.3 k R31, R32= 15 k R36= 22 P1= 250 , multiturn preset (upright) P2= 500 , multitun preset (upright) P3= 500 k, multiturn preset (upright) Capacitors: C1, C3= 0.1 F C2= 0.001 F C4, C5, C6, C8, C12C17=0.1 F, ceramic C7= 0.47 F C9, C18, C19, C22= 4.7 F, 63 V, radial C10= 10 F, 63 V, radial C11, C23= 47 F, 25 V, radial C20= 1000 F, 25 V, radial C21= 470 F, 25 V, radial C24C26= 0.047 F, ceramic Semiconductors: D1, D2= BAT82 D3, D4= BAS45A D5, D7= 1N4148 D6, D8, D9, D13= 3 mm high-efficiency LED (yellow, red, green, green respectively) D10, D11= 1N4007 D12= 1N4001 T1, T3, T5, T6= BC547B T2, T4= BD140 Integrated circuits: IC1= OP249GP (Analog Devices) IC2= LM319N IC3= 74HC4060 IC4= 74HC175 IC5, IC6= 4N35 IC7= 7812 IC8= 7912 IC9= 7805 Miscellaneous: JP1= 2.54 mm pin strip and pin jumper K1, K2= 3-way terminal block, pitch 5 mm K3= 2-way terminal block, pitch 5 mm K4= 2-way terminal block, pitch 7.5 mm B1= bridge rectifier, rectangular, Type B80C1500 F1= fuse, 50 mAT and fuse holder Tr1= mains transformer, 15 VA, with 215 V secondary Heat sink (for IC7) = e.g. Fischer SK104, 50 mm Mains interference filter Figure 5. The printed-circuit board of the overall protec- tion network. Contents D-type bistables (flip- flops), contained in IC4, which are inter- connected to form a shift register. Note that D-type bistables are essential since these can be set and reset in a defined manner. The outputs of IC4are used to drive two level converters, T1-T2and T3-T4 respectively, which bridge the differ- ence between the 5 V level of the logic ICs and the 12 V supply for the relays. Jumper JP1enables a different, external supply voltage (VRE) to be used if 12 V relays are not employed. Transistors T1and T2drive Re1and Re2, which are the first to be energized (synchronously). On switch-off, capac- itor C9ensures that T2remains on for some milliseconds longer during which period Re3and Re4are deener- gized (see Part 1). The power-on delay, which also operates after a fault situation, is more complex than usual. To start with, after the supply voltage us switched on, input CLR of IC4is held low (active) for a few seconds by the circuit around T6. When, after this period, CLR is made high by R12which happens only when there is no error situation (any longer)the internal oscillator of IC3is enabled via D5. This results after a few seconds in a clock pulse appear- ing at the CLK input of IC4, where- upon Q4goes high. The period between the oscillator being enabled and the appearance of the first clock pulse is not defined since, owing to the presence of T6, a power-on reset is purposely not provided. To ensure a minimum delay in the energizing of Re1and Re2in spite of this, a high level is clocked into Q4after IC3has been enabled. The pre- cise moment at which this happens varies, therefore, only when the supply voltage is switched on for the first time. A period of IC3/Q3later, Q1of IC4 goes high, whereupon Re1and Re2are energized. After another period, Q2of IC4becomes high, whereupon Re3and Re4are energized. At the same time, IC3is disabled since its reset is inter- linked with Q2 of IC4. The red LED, D8, in parallel with Q1 of IC4lights when the relays in the amplifier are not energized, either because the amplifier is (not yet) switched on, or owing to an error. The yellow LED, D6, is linked to the output of the oscillator in IC3, causing it to flash until IC4is clocked. The green LED, D9, is connected in parallel with Re3and Re4, so that it lights only when the amplifier is fully switched on. T R A N S F O R M E R V O L T A G ES E N S O R The 50 V secondary voltages of the mains transformers in the amplifier are rectified by diodes D10and D11, and smoothed by R30-R31-R32-C10. The val- ues of these components ensure that the LED in optoisolator IC6lights suf- ficiently to hold the associated photo transistor on. This transistor pulls the base of T5to ground, causing T5to cut off. When the secondary voltages fail, T5is switched on immediately via R29, whereupon the D-type bistables in IC4 are reset. Use is made of an optoisolator pur- posely to avoid any risk of earth loops between the supply return and the ground of the protection network, which is linked to the input ground of the amplifier. T E M P E R A T U R ES E N S O R The temperature sensor works in a manner similar to that of the trans- former voltage sensor. The optoisolator in this circuit is IC5, which, in contrast to IC6, is normally cut off and comes on only when the heat sink becomes excessively hot. The sensor reacts to the fan control circuit switching the fan speed to max- imum (because the heat sink is getting too hot). A comparator in the fan con- trol circuit then toggles, whereupon IC5is actuated via the temp input and resets the D-type bistables in IC4. This situation changes only after the heat sink has cooled down to an acceptable temperature (although the fans may still be rotating). C U R R E N TS E N S O R To nullify high common-mode voltages and to prevent any risk of earth loops, the current sensor also uses an optoiso- lator, IC2(Figure 5). However, this is not 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 actuated when the output current is about 40 A. This may appear a very large current, but this is due entirely to the specified requirement that the amplifier must be capable of delivering 60 V into a load of 1.5 without the protection circuit being actuated. The current level may be lowered to some extent by increas- ing the value of R74in the amplifier. Output resistor R78is in parallel with R12by linking terminals I, +5 V and ground on the amplifier board to K1on the protection board via three lengths of insulated, stranded circuit wire twisted together. This arrange- 35 Elektor Electronics3/99 Figure 6. Completed pro- totype of the protection network. Contents 37 Elektor Electronics3/99 ment ensures a low impedance to any interference and a high reaction speed. D I R E C T-C U R R E N TA N D O V E R D R I V ES E N S O R The d.c. and overdrive sensor con- stantly compares the input and output signals of the amplifier and reacts when the difference between the two is too great. The comparison is effected with the aid of operational amplifier IC1which has a very low bias current and a very low offset. It is, of course, essential that during the comparison of the two signals by differential amplifier IC1bthe 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 be taken into account. The amplification is compensated by potential divider R1-R2-P1at input LSP . The potentiometer is a multiturn type to ensure accurate adjustment. The phase difference is compen- sated by the circuit based on IC1a. The transit at high and low cut-off points is simulated by first-order networks that can also be adjusted very accu- rately with multiturn poten- tiometers P2and P3. The inputs of IC1aand IC1b are protected by diodes. Since any leakage current of these diodes, com- bined with the high input impedance ( 1 M) of IC1a, might lead to an appreciable offset, and therefore to an unwanted error detection, the diodes, D3and D4, are special types with a leakage current of only 1 nA. The output of differential amplifier IC1bis monitored by a window com- parator formed by IC2aand IC2b. The value of the components used in potential dividers R8-R9and R10-R11 ensures that the protection circuit is actuated when the direct voltage reaches a level of 5V or the distortion becomes 2.5 per cent. Such distortion will normally be the result of over- drive, but the circuit reacts equally well to oscillations or other spurious signals that cause too large a difference to be detected. C O N S T R U C T I O NA N D S E T T I N GU P The integrated protection network is best built on the printed-circuit board shown in Figure 5. Populating this board should not present any undue difficulties, but it should be noted that diodes D6, D8, D9and D13, are not located on the board, but are linked to it 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 coil voltage other than 12 V are used. A prototype of the completed pro- tection board is shown in Figure 6. All input and output terminals of the board are clearly marked with the same symbols as shown in Figure 4. Most interconnections can be made in thin, stranded hook-up wire to DEF61-12, but the input and output links (input and LSP) must be screened audio cable. Although the power supply for the protection network can be fitted on the same board, the relevant section may be cut off and fitted elsewhere. Of course, the supply lines must then be linked to the relevant terminals on the protection board via insulated, stranded hook-up wire. The power supply is straightfor- ward. From the secondary output of the specified mains transformer, Tr1, a symmetrical 12 V supply is obtained with the aid of regulators IC7and IC8. From the same secondary, a +5 V sup- ply for the digital circuits is obtained with the aid of regulator IC9. Since the relays 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 on the mains supply, it is advisable to pre- cede the power supply by a suitable noise filter. This may be made from a 30 H choke and two 0.1 F, 300 V capacitors as shown in dashed lines in Figure 4. The network is set up by maximiz- ing the common-mode suppression (C) ELEKTOR 990001-3 C1 C2 C3 C4 D1 D2 D3 D4 D5 D6 D7 D8 F1 F2 H1 H2 H3 H4 K1 K2K3K4R1R2 TR1 TR2 990001-3 0-+ 0.16AT 0.16AT (C) ELEKTOR 990001-3 7 Parts lists Auxiliary power supply Resistors: R1, R2= 1 M Capacitors: C1, C2= 470 F, 100 V, radial C3, C4= 0.1 F, 100 V, pitch 7.5 mm Semiconductors: D1D8= 1N4007 Miscelleneous: K1= 2-way terminal block, pitch 7.5 mm K2= 3-way terminal block, pitch 7.5 mm K3, K4= 2-way terminal block, pitch 5 mm Tr1, Tr2= mains transformer, 1.5 VA, with 12 V secondart F1, F2= fuse, 160 mAT, and fuse holder Figure 7. Printed-circuit board for the auxiliary power supply described in Part 1. Contents 38 Elektor Electronics3/99 200V / 35A 200V / 35A 2x 50V 500VA 2x 50V 500VA 2A5 T 2A5 T 990001 - 2 - 12 70V 70V 1000VA 6x 22000 / 100V mains power-on delay mains power-on delay e.g. 974078 - 1 e.g. 974078 - 1 9 with the aid of an oscilloscope or a multimeter with sufficient bandwidth. Measurements need to be made at 1 kHz, 20 kHz, and 20 Hz. The open- circuit amplifier is driven as far as pos- sible by a suitable sine-wave generator or CD player with a test CD. With a signal of 1 kHz, set P1for minimum sign al at the output of IC1b, follow this with a signal of 20 kHz and adjusting P2, and finally, with a signal of 20 Hz, by adjusting P3. Since the set- tings influence one another to some extent, the potentiometers should be set a couple of times, perhaps also at some different audio frequencies. P O W E RS U P P L Y The auxiliary power supply described in Part 1 is best constructed on the printed-circuit board shown in Fig- ure 7. The mains voltage is linked to K1, the 70 V to K2and the +85 V and 85 V lines to K3and K4respectively. Since all currents are low level, the wiring may be made in thin, insulated, stranded hook-up wire. A completed prototype board is shown in Figure 8. The main supply for the amplifier is a straightforward, unregulated type, providing an output of 70 V. Its cir- cuit diagram is shown in Figure 9. Since the specified requirements call for a 2 load, the supply must be rated at 1000 VA, which necessitates two toroidal transformers. To prevent unforeseen equalizing currents, the dual secondaries are not linked in par- allel, but are individually connected to a bridge rectifier. The outputs of the rectifiers can be connected in parallel without any problem. The rectifiers need to be mounted on a suitable heat sink such as a Type SK01. It should be clear that the wiring of the power supply must allow for the large out- put currents of the amplifier. In the proto- type, the electrolytic capacitors are linked by 3 mm thick strips of aluminium. The remainder of the wiring should be in insulated, high-current wire to BS6231 with a conductor 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 as described is intended for use with a mono(phonic) ampli- fier that can deliver 800 W into 2 and should remain stable with loads of 1.5 . If you are certain that you will always use 4 or 8 loads, the power supply requirements may be relaxed to some extent. A reasonable relaxation is the use of 250V/300VA transformers and 10,000 F/100 V smoothing capacitors. The rating of the primary fuse