LTC3780英文原版手册_图文

1、T YPICAL APPLICATIONF EATURESA PPLICATIONSD ESCRIPTION High Ef ciency, Synchronoous, 4-Switch Buck-Boost ControllerThe L TC ®3780 is a high performance buck-boost switch-ing regulator controller that operates from input voltagesabove, below or equal to the output voltage. The constant frequency

2、 current mode architecture allows a phase-lock-able frequency of up to 400kHz. With a wide 4V to 30V (36V maximum input and output range and seamless transfers between operating modes, the L TC3780 is ideal for automotive, telecom and battery-powered systems.The operating mode of the controller is d

3、etermined through the FCB pin. For boost operation, the FCB mode pin can select among Burst Mode ® operation, D iscontinuous mode and forced continuous mode. During buck operation, the FCB mode pin can select among skip-cycle mode, discon-tinuous mode and forced continuous mode. Burst Mode oper

4、ation and skip-cycle mode provide high ef ciency operation at light loads while forced continuous mode and discontinuous mode operate at a constant frequency. Fault protection is provided by an output overvoltage comparator and internal foldback current limiting. A power good output pin indicates wh

5、en the output is within 7.5% of its designed set point.High Ef ciency buck-Boost ConverternSingle Inductor Architecture Allows V IN Above, Below or Equal to V OUTn Wide V INRange: 4V to 36V Operation n Synchronous Recti cation: Up to 98% Ef ciency n Current Mode Controln ±1% Output Voltage Accu

6、racy: 0.8V < V OUT < 30V n Phase-Lockable Fixed Frequency: 200kHz to 400kHz n Power Good Output Voltage Monitor n Internal LDO for MOSFET Supplyn Quad N-Channel MOSFET Synchronous Drive n V OUT Disconnected from V IN During Shutdown n Adjustable Soft-Start Current Ramping n Foldback Output Cur

7、rent Limiting n Selectable Low Current Modes n Output Overvoltage Protectionn Available in 24-Lead SSOP and Exposed Pad (5mm × 5mm 32-Lead QFN PackagesnAutomotive Systems n Telecom Systemsn DC Power Distribution Systemsn High Power Battery-Operated Devices n Industrial Control, L T , L TC and L

8、 TM are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners.Protected by U.S. Patents including 5481178, 6304066, 5929620, 5408150, 6580258, patent pending on c

9、urrent mode architecture and protection+V IN TG20.1F 0.1FBOOST2SW2BG2TG1BOOST1SW1BG1PLLIN RUN V OSENSEI TH SSSGND FCB 0.0104.7FABDC 2200pF1F CER100F 16V CER330F 16VON/OFF0.1F4.7H20kPGOOD L TC3780INTV CC SENSE +SENSE PGND7.5k 1%105k 1%22F 50V CERV IN 5V TO 32VV OUT 12V 5A+V IN (VE F F I C I E N C Y (

10、%POWER LOSS (W909510015253780 TA01b8580510203035757089107654321Ef ciency and Power Loss V OUT = 12V , I LOAD = 5AA BSOLUTE MAXIMUM RATINGS Input Supply Voltage (V IN . 0.3V to 36V Topside Driver Voltages (BOOST1, boost2 . 0.3V to 42V Switch Voltage (SW1, SW2 . 5V to 36V INTV CC , EXTV CC , RUN, SS,

11、(BOOST SW1,(BOOST2 SW2, PGOOD . 0.3V to 7V PLLIN Voltage . 0.3V to 5.5V PLLFL TR Voltage .0.3V to 2.7V FCB, STBYMD Voltages . 0.3V to INTV CC I TH , V OSENSE Voltages . 0.3V to 2.4V(Note 1Peak Output Current <10s (TG1, TG2, BG1, BG2 .3A INTV CC Peak Output Current . 40mA Operating Temperature Ran

12、ge (Note 7 L TC3780E .40°C to 85°C L TC3780I.40°C to 125°C Junction Temperature (Note 2 . 125°C Storage Temperature Range .65°C to 125°C Lead Temperature (Soldering, 10 sec SSOP Only .300°CORDER INFORMATIONLEAD FREE FINISH TAPE AND REEL PART MARKINGPACKAGE DES

13、CRIPTION TEMPERATURE RANGE L TC3780EG#PBF L TC3780EG#TRPBF 24-Lead Plastic SSOP 40°C to 85°C L TC3780IG#PBF L TC3780IG#TRPBF 24-Lead Plastic SSOP40°C to 125°C L TC3780EUH#PBF L TC3780EUH#TRPBF 378032-Lead (5mm × 5mm Plastic QFN 40°C to 85°C L TC3780IUH#PBF L TC3780

14、IUH#TRPBF 3780I 32-Lead (5mm × 5mm Plastic QFN 40°C to 125°C LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE L TC3780EG L TC3780EG#TR 24-Lead Plastic SSOP 40°C to 85°C L TC3780IG L TC3780IG#TR 24-Lead Plastic SSOP40°C to 125°C L T

15、C3780EUH L TC3780EUH#TR 378032-Lead (5mm × 5mm Plastic QFN 40°C to 85°C L TC3780IUHL TC3780IUH#TR3780I 32-Lead (5mm × 5mm Plastic QFN40°C to 125°CConsult L TC Marketing for parts speci ed with wider operating temperature ranges.For more information on lead free part mar

16、king, go to: http:/www.linear .com/leadfree/For more information on tape and reel specications, go to: http:/www.linear .com/tapeandreel/123456789101112TOP VIEWG PACKAGE24-LEAD PLASTIC SSOP 242322212019181716151413PGOODSS SENSE +SENSE I TH V OSENSE SGND RUN FCBPLLFL TR PLLIN STBYMD BOOST1TG1SW1V IN

17、EXTV CC INTV CC BG1PGND BG2SW2TG2BOOST2T JMAX = 125°C, JA = 130°C/W32313029282726259101112TOP VIEW 33UH PACKAGE32-LEAD (5mm s 5mm PLASTIC QFN13141516171819202122232487654321SENSE +SENSE I TH V OSENSE SGND RUN FCB PLLFTR SW1V IN EXTV CC INTV CC BG1PGND BG2SW2N CS SP G O O DN CN CB O O S T 1

18、T G 1N CN CP L L I NS T B Y M DN CN CB O O S T 2T G 2N CT JMAX = 125°C, JA = 34°C/WEXPOSED PAD (PIN 33 IS GND, MUST BE SOLDERED TO PCBP IN CONFIGURATIONE LECTRICAL CHARACTERISTICSThel denotes the speci cations which apply over the full operating temperature range, otherwise speci cations a

19、re at T A = 25°C. V IN = 15V unless otherwise noted.SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Main Control LoopV OSENSE Feedback Reference Voltage I TH = 1.2V, 40°C T 85°C (Note 340°C T 125°C ll0.7920.7920.8000.8000.8080.811VVI VOSENSE Feedback Pin Input Current(Note 355

20、0nAV LOADREG Output Voltage Load Regulation(Note 3I TH = 1.2V to 0.7VI TH = 1.2V to 1.8V ll0.5%V REF(LINEREGReference Voltage Line Regulation V IN = 4V to 30V, I TH = 1.2V (Note 30.0020.02%/V g m(EAError Ampli er T ransconductance I TH = 1.2V, Sink/Source = 3A (Note 30.32mS g m(GBWError Amp

21、li er GBW0.6MHzI Q Input DC Supply CurrentNormalStandbyShutdown Supply Current (Note 4V RUN = 0V, V STBYMD > 2VV RUN = 0V, V STBYMD = Open240015005570AAAV FCB forced continuous Threshold0.760.8000.84V I FCB forced continuous Pin Current V FCB = 0.85V0.300.180.1A V BINHIBIT Burst Inhibit (Constant

22、 FrequencyThresholdMeasured at FCB Pin 5.3 5.5V UVLO Undervoltage Reset V IN Falling l 3.84V V OVL Feedback Overvoltage Lockout Measured at V OSENSE Pin0.840.860.88V I SENSE Sense Pins Total Source Current V SENSE = V SENSE+ = 0V380A V STBYMD(STARTStart-Up Threshold V STBYMD Rising0.40.7V V STBYMD(K

23、AKeep-Alive Power-On Threshold V STBYMD Rising, V RUN = 0V 1.25V DF MAX, boost Maximum Duty Factor% switch C On99% DF MAX, buck Maximum Duty Factor% switch A On (in Dropout99% V RUN(ONRUN Pin On Threshold V RUN Rising1 1.52V I SS Soft-Start Charge Current V RUN = 2V0.5 1.2AV SENSE(MAXMaximum Current

24、 Sense Threshold Boost: V OSENSE = V REF 50mVBuck: V OSENSE = V REF 50mV ll95160130185150mVmVV SENSE(MIN,BUCKMinimum Current Sense Threshold Discontinuous Mode6mV TG1, TG2 t r TG Rise Time C LOAD = 3300pF (Note 550ns TG1, TG2 t f TG Fall Time C LOAD = 3300pF (Note 545ns BG1, BG2 t r BG Rise Time C L

25、OAD = 3300pF (Note 545ns BG1, BG2 t f BG Fall Time C LOAD = 3300pF (Note 555ns TG1/BG1 t1D TG1 Off to BG1 On Delay,Switch C On DelayC LOAD = 3300pF Each Driver80nsBG1/TG1 t2D BG1 Off to TG1 On Delay,Synchronous switch D On DelayC LOAD = 3300pF Each Driver80nsTG2/BG2 t3D TG2 Off to BG2 On Delay,Synch

26、ronous switch B On DelayC LOAD = 3300pF Each Driver80nsBG2/TG2 t4D BG2 Off to TG2 On Delay,Switch A On DelayC LOAD = 3300pF Each Driver80nsModeT ransition 1BG1 Off to BG2 On Delay,Switch A On DelayC LOAD = 3300pF Each Driver90nsE LECTRICAL CHARACTERISTICSThel denotes the speci cations which apply ov

27、er the full operating temperature range, otherwise speci cations are at T A = 25°C. V IN = 15V unless otherwise noted.SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITSModeT ransition 2BG2 Off to BG1 On Delay,Synchronous switch D On DelayC LOAD = 3300pF Each Driver90nst ON(MIN,BOOSTMinimum On-Time f

28、or Main switch inboost OperationSwitch C (Note 6200nst ON(MIN,BUCKMinimum On-Time for synchronousswitch in buck OperationSwitch B (Note 6180ns Internal V CC RegulatorV INTVCC Internal V CC Voltage7V < V IN < 30V, V EXTVCC = 5V l 5.76 6.3V V LDO(LOADREGInternal V CC Load Regulation I CC = 0mA t

29、o 20mA, V EXTVCC = 5V0.22% V EXTVCC EXTV CC switchover Voltage I CC = 20mA, V EXTVCC Rising l 5.4 5.7V V EXTVCC(HYSEXTV CC switchover Hysteresis200mV V EXTVCC EXTV CC switch Drop Voltage I CC = 20mA, V EXTVCC = 6V150300mV Oscillator and Phase-Locked Loopf NOM Nominal Frequency V PLLFL TR = 1.2V26030

30、0330kHz f LOW Lowest Frequency V PLLFL TR = 0V170200220kHz f HIGH Highest Frequency V PLLFL TR = 2.4V340400440kHz R PLLIN PLLIN Input Resistance50kI PLLLPF Phase Detector Output Current f PLLIN < f OSCf PLLIN > f OSC 1515AAPGOOD OutputV FBH PGOOD Upper Threshold V OSENSE Rising 5.57.510%V FBL

31、PGOOD Lower Threshold V OSENSE Falling5.57.510%V FB(HYSTPGOOD Hysteresis V OSENSE Returning 2.5% V PGL PGOOD Low Voltage I PGOOD = 2mA0.10.3V I PGOOD PGOOD Leakage Current V PGOOD = 5V±1ANote 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device

32、. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime.Note 2: T J for the QFN package is calculated from the temperature T A and power dissipation P D according to the following formula:T J = T A + (P D 34°C/WNote 3: The IC is tested

33、 in a feedback loop that servos V ITH to a speci ed voltage and measures the resultant V OSENSE.Note 4: Dynamic supply current is higher due to the gate charge being delivered at the switching frequency. Note 5: Rise and fall times are measured using 10% and 90% levels. Delay times are measured usin

34、g 50% levels.Note 6: The minimum on-time condition is speci ed for an inductor peak-to-peak ripple current 40% of I MAX (see minimum on-time considerations in the Applications Information section.Note 7: The L TC3780E is guaranteed to meet performance speci cations from 0°C to 85°C. Perfor

35、mance over the 40°C to 85°C operating temperature range is assured by design, characterization and correlation with statistical process controls. The L TC3780I is guaranteed over the40°C to 125°C operating temperature range.T YPICAL PERFORMANCE CHARACTERISTICS Ef ciency vs Output

36、 Current(Boost OperationEf ciency vs Output CurrentEf ciency vs Output Current(Buck OperationSupply Current vs Input VoltageInternal 6V LDO Line RegulationEXTV CC Voltage Drop INTV CC and EXTV CC switch Voltage vs TemperatureEXTV CC switch Resistance vs TemperatureLoad RegulationT A = 25°C unle

37、ss othewise noted.I LOAD (A0.0140E F F I C I E N C Y (%80901000.11103780 G01706050BURST DCMCCMV IN = 6V V OUT = 12VI LOAD (A0.0140E F F I C I E N C Y (%80901000.11103780 G02706050BURSTDCMCCMV IN = 12V V OUT = 12VI LOAD (A0.0140E F F I C I E N C Y (%80901000.11103780 G03706050SCDCMCCM V IN = 18V V OU

38、T = 12VINPUT VOLTAGE (V50S U P P L Y C U R R E N T (A 100025001020253780 G0450020001500153035V FCB = 0VSTANDBYSHUTDOWNINPUT VOLTAGE (V0I N T V C C V O L T A G E (V 5.56.06.515253780 G055.04.55102030354.03.5CURRENT (mA00E X T V C C V O L T A G E D R O P (m V 20406080100120102030403780 G0650 TEMPERATU

39、RE (°C505.55I N T V C C A N D E X T V C C S W I T C H V O L T A G E (V 5.605.705.755.806.055.90050753780 G075.655.956.005.852525100125INTV CC VOLTAGEEXTV CC SWITCHOVER THRESHOLDTEMPERATURE (°C50250E X T V C C S W I T C H R E S I S T A N C E (25050753780 G0814325100125LOAD CURRENT (AN O R M

40、 A L I Z E D V O U T (%0.20.143780 G01235V IN = 18VFCB = 0V V OUT = 12V V IN = 12VV IN = 6V63780fdContinuous Current Mode(CCM, V IN = 6V , V OUT = 12VContinuous Current Mode (CCM, V IN = 12V , V OUT = 12VContinuous Current Mode (CCM, V IN = 18V , V OUT = 12VBurst Mode Operation (V IN = 6V

41、, V OUT = 12VBurst Mode Operation (V IN = 12V , V OUT = 12VSkip Cycle Mode(V IN = 18V , V OUT = 12VDiscontinuous Current Mode (DCM, V IN = 6V , V OUT = 12VDiscontinuous Current Mode (DCM, V IN = 12V , V OUT = 12VDiscontinuous Current Mode (DCM, V IN = 18V , V OUT = 12VT YPICAL PERFORMANCE CHARACTERI

42、STICS T A = 25°C unless othewise noted.SW210V/DIVSW110V/DIV V OUT 100mV/DIV5s/DIVV IN = 6V V OUT = 12V3780 G10I L 2A/DIVSW210V/DIV SW110V/DIVV OUT 200mV/DIV10s/DIVV IN = 12V V OUT = 12V3780 G14I L 2A/DIVSW210V/DIV SW110V/DIVV OUT 100mV/DIV5s/DIVV IN = 6V V OUT = 12V3780 G16I L 1A/DIV73780fdOsci

43、llator Frequencyvs TemperatureUndervoltage Reset vs TemperatureMinimum Current SenseThreshold vs Duty Factor (BuckMaximum Current SenseThreshold vs Duty Factor (BoostMaximum Current SenseThreshold vs Duty Factor (BuckMinimum Current Sense Threshold vs TemperaturePeak Current Threshold vs V ITH (Boos

44、tValley Current Threshold vs V ITH (BuckCurrent Foldback LimitT YPICAL PERFORMANCE CHARACTERISTICS T A = 25°C unless othewise noted.TEMPERATURE (°C500F R E Q U E N C Y (k H z 50150200250504503780 G191000257510025125300350400V PLLFLTR = 2.4V V PLLFLTR = 1.2VV PLLFLTR = 0VTEMPERATURE (°

45、C50253.0U N D E R V O L T A G E R E S E T (V 3.44.0050753780 G25100 125DUTY FACTOR (%80I S E N S E + (m V 604020806040203780 G21 100DUTY FACTOR (%0I S E N S E + (m V 140160803780 G221201002040 60100180DUTY FACTOR (%110I S N E S E + (m V 120130140204060803780 G23 1000TEMPERATURE (°C50

46、5010020025753780 G240502550100125100150150M A X I M U M I S N E S E + T H R E S H O L D (m V BOOSTBUCKV ITH (V0100I S E N S E + (m V 50050100200 1.63780 G251.8 2.4150V ITH (V0150I S E N S E + (m V 10050050100 1.6 3780 G262.0 2.4V OSENSE (V00I S E N S E + (m V 4080120160200BUCKBOOST

47、 3780 G320.883780fdP IN FUNCTIONS Load StepLoad StepLoad StepLine T ransient Line T ransientT YPICAL PERFORMANCE CHARACTERISTICS T A = 25°C unless othewise noted.V OUT 500mV/DIV200s/DIV V IN = 18V V OUT = 12VLOAD STEP: 0A TO 5A CONTINUOUS MODE3780 G27I L 5A/DIV(SSOP/QFNPGOOD (Pin 1/Pin

48、 30: Open-Drain Logic Output. PGOOD is pulled to ground when the output voltage is not within ±7.5% of the regulation point.SS (Pin 2/Pin 31: Soft-start reduces the input power sources surge currents by gradually increasing the controllers current limit. A minimum value of 6.8nF is recommended

49、on this pin.SENSE + (Pin 3/Pin 1: The (+ Input to the Current Sense and Reverse Current D etect Comparators. The I TH pinvoltage and built-in offsets between SENSE and SENSE + pins, in conjunction with R SENSE , set the current trip threshold.SENSE (Pin 4/Pin 2: The ( Input to the Current Sense and

50、Reverse Current Detect Comparators.I TH (Pin 5/Pin 3: Current Control Threshold and Error Ampli er Compensation Point. The current comparator threshold increases with this control voltage. The voltage ranges from 0V to 2.4V .P IN FUNCTIONS(SSOP/QFNV OSENSE (Pin 6/Pin 4: Error Ampli er Feedback Input

51、. This pin connects the error ampli er input to an external resistor divider from V OUT.SGND (Pin 7/Pin 5: Signal Ground. All small-signal com-ponents and compensation components should connect to this ground, which should be connected to PGND at a single point.RUN (Pin 8/Pin 6: Run Control Input. F

52、orcing the RUN pin below 1.5V causes the IC to shut down the switching regulator circuitry. There is a 100k resistor between the RUN pin and SGND in the IC. Do not apply >6V to this pin. FCB (Pin 9/Pin 7: Forced continuous Control Input. The voltage applied to this pin sets the operating mode of

53、the controller. When the applied voltage is less than 0.8V, the forced continuous current mode is active. When this pin is allowed to oat, the burst mode is active in boost opera-tion and the skip cycle mode is active in buck operation. When the pin is tied to INTV CC, the constant frequency discont

54、inuous current mode is active in buck or boost operation.PLLFLTR (Pin 10/Pin 8: The Phase-Locked Loops Lowpass Filter is Tied to This Pin. Alternatively, this pin can be driven with an AC or DC voltage source to vary the frequency of the internal oscillator.PLLIN (Pin 11/Pin 10: External Synchroniza

55、tion Input to Phase Detector. This pin is internally terminated to SGND with 50k. The phase-locked loop will force the rising bottom gate signal of the controller to be synchronized with the rising edge of the PLLIN signal.STBYMD (Pin 12/Pin 11: LDO Control Pin. Determines whether the internal LDO r

56、emains active when the control-ler is shut down. See Operation section for details. If the STBYMD pin is pulled to ground, the SS pin is internally pulled to ground, preventing start-up and thereby provid-ing a single control pin for turning off the controller. To keep the LDO active when RUN is low, for example to power a “wake