Crest-Pulse-series-pwr-sm维修电路原理图.pdf

T E C H N I C A L S P E C I F I C A T I O N STechnical SpecificationsPower RatingsPulse 4x300Pulse 2x650Pulse 2x1100Measured per channel, both channels driven at 1kHz to no more than 0.1% THD+N8 Ohms170Wrms400Wrms700Wrms4 Ohms300Wrms650Wrms1100Wrms2 Ohms330Wrms*850Wrms*1500Wrms* Note: 2 Ohm spec is at 1% THDBridged Mono16 Ohms400Wrms800Wrms1200Wrms8 Ohms600Wrms1300Wrms2200Wrms4 Ohms660Wrms*1700Wrms*3000Wrms* Note: 4 Ohm bridged spec is at 1% THDInput Sensitivity+1dBu for full outputInput Impedance20kOhmDistortion0.006% THD, 1kHz, 1dB below clip,22kHz measurement bandwidthFrequency Resp.20Hz to 20kHz, +0/-0.2dB;120kHz +0/-3dBControlsPower switch, bridge mode switching,indented level controls (these maybe made tamper-proof)IndicatorsMains present, Operate, Signal, Bridge,Clip, Overtemperature, Protect, RemoteProtectionMicroprocessor supervised:overtemperature, DC on outputs, outputstage overload, inrush current surge,mains fail and brownout.Noise50 V/microsecondDamping Factor200 ref 8 OhmOutput Connectors4x300 - Binding post or Speakon2x650, 2x1100 - Binding post and SpeakonPower115 or 230 volts AC nominal, internallyselectable, 2000VA, all channelsdriven (4x300, 2x650); 3000VA (2x1100)Dimensions3.5 (89mm) x 18.2 (460mm) x 19 (483mm)- with rear rack ears depth 19.5”, -21”, 20” (494, 511, 530mm)Weight24lbs (11kg)Trade Descriptions Act: C Audio have a policy of continued product improvement and accordinglyreserve the right to change features and specifications without prior notice.Benefits of thePulse Series Very light weight Switched mode power supplies give solid performance at all power levels Microprocessor protection system Massive heatsinks for cooler operation and higher reliability Binding Post or Speakon output connector options Optional Remote control via C Audio CONNECT Internal crossover card optionsPulse 4x300Into 8 Ohms170WInto 4 Ohms300WInto 2 Ohms330WPulse 2x650Into 8 Ohms400WInto 4 Ohms650WInto 2 Ohms850WPulse 2x1100Into 8 Ohms700WInto 4 Ohms1100WInto 2 Ohms1500WPower RatingsThe Pulse Series com-bines state-of-the-artswitched mode powersupplies to not onlyreduce amplifier weightby as much as 70%compared to conventionalamps, but also to providesolid, consistentperformance at all powerlevels.Occupying just 2U of rackspace, Pulse usesmassive heatsinks andfront-venting fans tokeep the electronicsreally cool, plus a built-inmicroprocessor whichcontinually monitors allthe protection aspects ofPulse - these factors alldramatically enhancereliability.Pulse amplifiers willperform for longerperiods than conventionalamplifiers at high outputlevels.The combination of theswitched mode PSU and arugged steel chassismeans inherent strength.Cooler, Lighter, StrongerPulse SeriesMarch 2000RadioFans.CN 收音机爱 好者资料库Pulse P2X1100 circuit description1. switching power supply2. power amplifiers3. protection4. frontpanel & flashing lights5. PIC and system protectionRadioFans.CN 收音机爱 好者资料库1. Switching Power SupplyMains voltage is inserted via filtered IEC CN3. Earth is connected directly to chassis from thebody of CN3. Live passes through fuse F2.Live and Neutral pass though a further filter consisting of C2 (X2 rated), L1 - a common modechoke - and C15 & 14 (Y2 rated).Live passes through the soft-start system, TH1, R14 and RLY1. R14 limits the initial currentsurge caused by the primary reservoir capacitors charging up. TH1 protects R14 if a faultcauses excessive dissipation in R14. RLY1 shorts out TH1 and R14 when the PSU is running.Live and Neutral then pass to bridge rectifier BR2 which, for the 230V setting full-waverectifies mains, smoothing performed by reservoir capacitors C22,23,44,45,32,33. In the 115Vsetting, this power supply is configured as a voltage doubler. Thus, the High Tension (+HT)DC generated is approximately equal for 230V mains and 115V mains.This will result in about 320Vdc between LIVE GND and +HT. LIVE GND is named as suchbecause it is not isolated from mains but it is the reference point for the PSU. If you need tostick a scope probe around the primary side with the unit plugged in you must connect mainsvia an Isolation Transformer. Without this, at best you will only trip your RCD breaker, atworst you or your scope may not live to regret it. Do not forget that 320Vdc is still prettyshocking whether it is isolated or not.R36 and R37 ensure proper voltage sharing of the reservoir capacitors.Power for the switching controller circuit is provided from two sources.At start-up, the power comes from R93,113, ZD2, D22 and C75. C75 is charged up to about47V through D22 from Zener regulator R93,113 and ZD2. The command to start the PSUcomes from the PIC (+5V for off, 0V to switch on) via R33. The LED in OPT1 is turned onwhich turns the transistor on, shorting out pins 5&4. While the transformer windings are coolerthan 1200C the thermal cut-out (TX5-B) will be a short circuit. So R166 will be connected tothe top of C75 and will form a Zener regulator with ZD9. The output of this zener regulator isbuffered by TR49 which then powers the switching controller circuit.C75 stores enough energy to run the controller for long enough until the second source ofpower is ready.The second source of power comes from the transformer on pins 3 and 14. This secondary isvoltage doubled by C82, D29,31 and C74 and produces about 48Vdc on VAUX. This isconnected via D32 to the top of C75 so the controller circuit can continue running.VAUX is used to directly power RLY1 to short TH1 and R14 out while the PSU is running.The circuit comprising R165,R172,ZD10,R178,TR47 and R180 shut down the PSU when thevoltage on C75 falls below about 32V. while the voltage on C75 is greater than 32V, TR47 isswitched on and pulls pin10 of IC6 down to 0V which enables IC6. When the voltage on C75falls below 32V, TR47 switches off and pin10 of IC6 is pulled up to 20V through R180,disabling IC6.R92,8,85,C67,ZD3 and TR23 form a time delayed drive for RYL2. At start-up, RLY2 will beopen and R127,145 will be in series with the primary of the transformer. These resistors limitthe current surge caused by charging up the secondary reservoir capacitorsC113,114,137,138. About 100ms after a successful start-up, TR23 will energise RLY2,shorting R127,145.The switching controller circuit is based around IC6, and SG3525 PWM controller. Switchingfrequency is set by R175 and C199 to about 85kHz. R176 controls the dead time period,setting it to between 500ns and 1s. Outputs appear at pins11 and 14. These two outputs arecomplementary, that is when one is high (20V), the other is low (0V). Due to the dead timecontrol, neither outputs are high at the same time but both are low for the dead time period.These outputs are fed through R169,170 to high current buffers TR40,41 and TR42,43. Thebuffered outputs push-pull drive the primary of Pulse transformer TX4. R160 is a dampingresistor used to minimise ringing caused by imperfections in TX4. The transformer has twosecondaries, each driving one IGBT in anti-phase. The turns ratio is 1.5:1 (pri:sec) and due tothe push-pull connection of the primary, the output of TX4 swings positive to about 15V to turnthe IGBT on, falls to 0V switching the IGBT off during dead time and falls to about -15V whilstthe other IGBT is switched on.IGBTs TR24,29 form a half bridge driver for TX5. D14,23 provide flyback protection forTR24,29. These are not fitted as we are currently using IGBTs with integral flyback diodes.Snubbers R84,C56,R117,C68 damp any ringing which may occur.The drive for the transformer from the IGBTs is an 85kHz square wave almost hitting +HT atthe top of its travel and bottoming out slightly above LIVE GND. This drive is connected tothe primary of TX5 at pins 15&16. The other end of the primary at pins 1&2 connects to LIVEGND through the closed RLY2 and C63,64,65.C63,64,65 perform two important functions.1.they prevent DC current flowing through TX5 thus preventing early saturation of the core.2.they form a discontinuous resonant circuit with the leakage and stray inductance of thetransformer. This means that the current will not be the same shape as the voltage. It isarranged that, for instance, positive current flow through TR24 will start from 0A, rise andfall in a half-sinusoidal fashion, reach 0A and stop before TR24 is switched off. This meansthat switching losses in the IGBTs are virtually eliminated because switching occurs whilst0A of current is flowing.There are two main secondaries.1. Pins 10,11,4&5 are the low voltage centre tapped secondary winding. Output of this is full-wave rectified by D49,50,54,55 and smoothed by C126,C132. Further filtering is providedby L2,3 and C120,130 before passing to 15V regulator IC7 and -15V regulator IC8. The+15V and -15V outputs are decoupled by C124,133 close to the regulators to ensurestability. C28 and C29 provide further decoupling close to the option connectors CN11,12.D51 half-wave rectifies the secondary output. This is lightly smoothed by C117 and loadedby R219. This is passed via ZD15,R34,R35 and C25 to the PIC. While the PSU is running,this circuit will produce a digital high at the PIC input. If the PSU stops for any reason, thesmall value of C117 means that the PIC will receive a digital low well before any of thePower supplies have drooped significantly allowing the PIC time to prevent plops.2. Pins is the main Power centre tapped stacked secondary. This is full-wave rectified byC45,48,53,61,57,60,36,47 and smoothed by C113,137,138,114 to produce HT+, HT- andMT+, MT- so that MT+ is half HT+ and MT- is half HT-. R7,112 roughly equalise thedischarge rate when the PSU is stopped.2. AmplifierRefer to channel 1The amplifier consists of a Class A driver and a Class AB rail switched power output stage.The driver provides voltage gain only, the output stage provides current gain only.Audio signal enters the amplifier through DC blocking capacitor C149, then low-pass filter R88& C51 and onto the base of TR30. R261 provides a low source impedance in case thefrontpanel board is disconnected. R89 provides a DC path to ground for the base current ofTR30.The output of the amplifier is fed-back through potential divider R104 and R102 to the base ofTR31. C58 decouples the feedback signal at DC so that DC offsets generated by TR30,31 arenot amplified at the output. D15,19 protect C58 in the event of a DC fault.TR30 and TR31 form a Long Tailed Pair to amplify the difference between the input signal andthe feedback signal. The gain of the LTP is reduced by R99 and R100 to help preventoscillations and de-sensitise the performance of the input stage to parametric variations of thetwo transistors. A bias current of about 2.8mA for this LTP is provided through R98 fromcurrent source TR19, R57, D6,7 & R75. In the quiescent state half of this current is driventhrough each of TR30 and TR31. The collector current of TR30 and TR31 pass through ZD7and ZD5 and are loaded through D27 and D26 by R137 and R146.The outputs of TR30 and TR31 are taken from the anodes of D27 and D26 to the bases ofanother LTP - TR38 and TR37. C70 determines the frequency response to ensure stability. Asbefore, R139 and R140 reduce the gain of this LTP and the bias current is set to about 8mAby R138. The collectors of TR37 and TR38 are loaded with a current mirror - TR20 & TR21 tomaximise gain and provide a push-pull output.Some of this output is fed-back to the base of TR31 through C63 and R103. This defines theopen-loop frequency response independently of the output stage characteristics to ensurestability.Finally, the Vbe multiplier - TR25, R82&83 - provides the output stage with two voltage signalswhich are identical except they are offset by a voltage varying between about 2.1V (heatsinkhot) and 2.4V (heatsink cold). C53 ensures that the two offset signals are identical at AC.The Current source consisting of TR19, R57, D6,7 and R75 determines the operating point ofthe whole class A driver. Therefore, one can mute the amplifier by switching this currrentsource off.The current source is switched off by TR18, R68 and C37. When TR18 is switched on, D6,7are shorted out through R68 which mutes the current source. C37 is discharged in theprocess. When TR18 is switched off, C37 charges up through R75 until D6,7 are fullyconducting which activates the current source.TR18 is controlled by TR11, R56, R46, ZD1, R47 and R48.If the PIC is absent or its +5V supply has failed the MUTE1 line will be in a high impedancestate, i.e. nothing doing. The 4.7V reference supplied by R46 & ZD1 and emitter resistor R47set the current through TR11 to about 200A. This is enough to switch TR18 on and mute theamplifier. This is the default state.When working, the PIC controls the state of the MUTE1 line. To mute the amplifier, theMUTE1 line is set to 0V. The current through TR11 is then set to about 4.2mA because R48is now essentially in parallel with R47. This mutes the amplifier as before.To activate the amplifier, the MUTE1 line is set to +5V. This, through R48, reverse biases thebase-emitter junction of TR11. Thus TR11 is switched off as is TR18 so the amplifierbecomes active.Under normal conditions the signals at the bases of TR30 and TR31 will be the same.However, under fault conditions, such as a DC offset at the output, the base voltages willbecome offset also. For example, in the event of a large DC offset of +50V at the output, apositive DC voltage will appear at the feedback point and hence at the base of TR31. This DCvoltage will make D65 conduct protecting C126, so the voltage at TR31 base should be 0.6 +50V x R102/(R102+R104), about 4V. However, the important issue is that the voltage ispositive. In the event the voltage is negative this indicates that the feedback divider is faulty.The voltage at TR31 base being positive whilst the base of TR30 is close to 0V will thenreverse bias TR31 base-emitter, turning off the transistor. Therefore, no voltage shouldappear across R100 and R146 whilst double the normal voltage will appear across R99 andR137. Should this not be the case, it indicates a fault in the input stage itself.The same process should now cause TR37 and TR20 &21 to be off and TR81 to be full onClass AB output stageThe input of the Output stage is loaded by C46. This defines the HF input impedance and thusaverts very nasty oscillations that are caused by the variable, non-linear and sometimesnegative raw input impedance. Resistors R60 and R182 ensure that output offsets areminimised when the amplifier is muted. D5 and D39 stop the Class A driver over-saturatingTR12 and TR55. D11 and D40 prevent the output exceeding the power supply rails in the faceof flyback pulses from reactive loads.The output stage consists of a symmetrical Siklai follower - TR12, TR13, R61, TR55, TR56,R181, R81, R80, C52, D13, D17 - generating the high current drive required for the parallelconnected symmetrical follower output stage - TR26, TR14, TR34, TR46, R115, R94, R121,R124, TR72, TR59, TR88, TR79, R147, R141, R168, R159. V-I limiting is controlled