NCP1252 - Current Mode PWM Controller ... - ON …

1 Semiconductor Components Industries, LLC, 2016 April, 2019 Rev. 81 Publication Order Number: NCP1252 /DNCP1252 Current Mode PWMC ontroller for Forward andFlyback ApplicationsThe NCP1252 Controller offers everything needed to build cost effective and reliable ac dc switching supplies dedicated to ATXpower supplies. Thanks to the use of an internally fixed timer, NCP1252 detects an output overload without relying on the auxiliaryVcc. A Brown Out input offers protection against low input voltagesand improves the converter safety. Finally a SOIC 8 package savesPCB space and represents a solution of choice in cost sensitive Peak Current Mode Control Adjustable Switching Frequency up to 500 kHz Jittering Frequency 5% of the Switching Frequency Latched Primary Over Current Protection with 10 ms Fixed Delay Delay Extended to 150 ms in E Version Delayed Operation Upon Start up via an Internal Fixed Timer(A, B and C versions only) Adjustable Soft start Timer Auto recovery Brown Out Detection UC384X like UVLO Thresholds Vcc Range from 9 V to 28 V with Auto recovery UVLO Internal 160 ns Leading Edge Blanking Adjustable Internal Ramp Compensation +500 mA / 800 mA Source / Sink Capability Maximum 50% Duty Cycle: A Version Maximum 80% Duty Cycle.

2 B Version Maximum 65% Duty Cycle: C Version Maximum Duty Cycle: D & E Versions Ready for Updated No Load Regulation Specifications SOIC 8 and PDIP 8 Packages These are Pb Free DevicesTypical Applications Power Supplies for PC Silver Boxes, Games Flyback and Forward ConverterSOIC 8 CASE 751 SUFFIX DPIN CONNECTIONSMARKING DIAGRAMS(Top View)OFFLINE A, B, C, D or EA= Assembly LocationL, WL= Wafer LotY, YY= YearW, WW = Work WeekG or G = Pb Free Package1252xALYWX G18 See detailed ordering and shipping information in the packagedimensions section on page 18 of this data INFORMATIONSSVCCDRVGNDFBBOCSRT1 PDIP 8 CASE 626 SUFFIX nF**Minimum recommendeddecoupling capacitor valueFigure 1. Typical ApplicationTable 1. PIN FUNCTIONSPin NameFunctionPin Description1 FBFeedbackThis pin directly connects to an optocoupler out inputThis pin monitors the input voltage image to offer a Brown out senseMonitors the primary Current and allows the selection of the ramp com-pensation elementA resistor connected to ground fixes the switching The Controller ground pin connects to the MOSFET gate7 VCCVCCThis pin accepts voltage range from 8 V up to 28 V8 SSTARTSoft startA capacitor connected to ground selects the soft start duration.

3 The softstart is grounded during the delay timerTable 2. MAXIMUM RATINGS TABLE (Notes 1 and 2)SymbolRatingValueUnitVCCP ower Supply voltage, Vcc pin, transient voltage: 10 ms with IVcc < 20 mA30 VVCCP ower Supply voltage, Vcc pin, continuous voltage28 VIVccMaximum Current injected into pin 720mAVDRVM aximum voltage on DRV pin to VCCVM aximum voltage on low power pins (except pin 6, 7) to 10VR JA PDIP8 Thermal Resistance Junction to Air PDIP8131 C/WR JA SOIC8 Thermal Resistance Junction to Air SOIC8169 C/WTJ(MAX)Maximum Junction Temperature150 CTSTGS torage Temperature Range 60 to +150 CESDHBMESD Capability, HBM Capability, Machine Model200 VStresses exceeding those listed in the Maximum Ratings table may damage the device.

4 If any of these limits are exceeded, device functionalityshould not be assumed, damage may occur and reliability may be This device series contains ESD protection and exceeds the following tests: Human Body Model 1800 V per JEDEC StandardJESD22 A114E. Machine Model Method 200 V per JEDEC Standard JESD22 This device contains latch up protection and exceeds 100 mA per JEDEC Standard + LEBCSR senseSRQfs wSRQDrvVccmana ge ments hutdown(FC S)Vbulk15 VBootstrap30 VGrandResetBOKUV LO r ampRcompUVLO+ VBOFa ul t Ti me rCountClockResetOutVdd+ LOGrand ResetSST ARTIssVddFi x e dDelay120 msSoft startRTFs wselection+ 1V+ Fs wi ngSoft StartStatusSRQR esetEndSet10 kHzclk2 bits counterMaxDCNote:MaxDC = 50% with A versionMaxDC = 80% with B versionFigure 2.

5 Internal Circuit ArchitectureRTVccUVLOQQQ resetMaxDC = 65% with C versionMaxDC = with D & E 3. ELECTRICAL CHARATERISTICS(VCC = 15 V, RT = 43 kW, CDRV = 1 nF. For typical values TJ = 25 C, for min/max values TJ = 25 C to +125 C, unless otherwise noted)CharacteristicsTest ConditionSymbolMinTypMaxUnitSUPPLY SECTION AND VCC MANAGEMENTS tartup threshold at which driving pulses are authorizedVCC increasingA, B, C versionsD & E versionsVCC(on) Operating voltage at which driving pulsesare stoppedVCC decreasingVCC(off) between VCC(on) and VCC(min)A, B and C versionsD & E versionsVCC(HYS) VStart up Current , Controller disabledVCC < VCC(on) & VCC increasingfrom zeroICC1 100mAInternal IC consumption, Controller switchingFsw =100 kHz, DRV = IC consumption, Controller switchingFsw =100 kHz, CDRV = 1 COMPARATORC urrent Sense Voltage Edge Blanking DurationtLEB 160 nsInput Bias Current (Note 3)Ibias mAPropagation delayFrom CS detected to gateturned offtILIM 70150nsInternal Ramp Compensation Voltage level@ 25 C (Note 4) Ramp Compensation resistance to CS pin@ 25 C (Note 4)Rramp kWINTERNAL OSCILLATORO scillator FrequencyRT = 43 kW & DRV pin = 47 kWfOSC92100108kHzOscillator FrequencyRT = kW & DRV pin = 47 kWfOSC425500550kHzFrequency Modulation in percentage of fOSC(Note 3)fjitter 5 %Frequency modulation Period(Note 3)

6 Tswing msMaximum operating frequency(Note 3)fMAX500 kHzMaximum duty cycle A duty cycle B versionDCmaxB768084%Maximum duty cycle C versionDCmaxC616569%Maximum duty cycle D & E SECTIONI nternal voltage division from FB to CS setpointFBdiv 3 Internal pull up resistorRpull up kWFB pin maximum currentFB pin = mAInternal feedback impedance from FB to GNDZFB 40 kWOpen loop feedback voltageFB pin = openVFBOL VInternal Diode forward voltage(Note 3)Vf VDRIVE OUTPUTDRV Source resistanceRSRC 1030 WDRV Sink resistanceRSINK 619 WOutput voltage rise timeVCC = 15 V, CDRV = 1 nF,10 to 90%tr 26 ns3. Guaranteed by design4. Vramp, Rramp Guaranteed by 3. ELECTRICAL CHARATERISTICS(VCC = 15 V, RT = 43 kW, CDRV = 1 nF.)

7 For typical values TJ = 25 C, for min/max values TJ = 25 C to +125 C, unless otherwise noted)CharacteristicsUnitMaxTypMinSymbol Test ConditionDRIVE OUTPUTO utput voltage fall timeVCC = 15 V, CDRV = 1 nF,90 to 10%tf 22 nsClamping voltage (maximum gate voltage)VCC = 25 VRDRV = 47 kW, CDRV = 1 nFVCL 1518 VHigh state voltage dropVCC = VCC(min) + 100 mV, RDRV= 47 kW, CDRV = 1 nFVDRV(clamp) 50500mVCYCLE SKIPSkip cycle threshold ResetVskip(reset) Vskip+Vskip(HYS) VSkip threshold HysteresisVskip(HYS) 25 mVSOFT STARTSoft start charge currentSS pin = start completion voltage delay before starting the Soft start whenVCC(on) is reachedFor A, B and C versions only No delay for D & E versionsSSdelay100120155msPROTECTIONC urrent sense fault voltage level triggering delay before latching a fault (overload orshort circuit) A/B/C/D versionsWhen CS pin > FCST fault101520msTimer delay before latching a fault (overload orshort circuit) E versionWhen CS pin > FCST fault120155200msBrown out Current source generating the Brown outhysteresis 5 C TJ +125 C 25 C TJ +125 Guaranteed by design4.

8 Vramp, Rramp Guaranteed by designTable 4. SELECTION TABLENCP1252 Start up DelayDuty Ratio MaxVCC Start (Typ.)Fault Timer (Typ.)FaultAYe s50%10 V15 msLatchedBYe s80%10 V15 msLatchedCYe s65%10 V15 V15 V150 CHARACTERISTICSF igure 3. Supply Voltage Threshold Temperature (A, B and C Versions)Figure 4. Supply Voltage Hysteresis Temperature (A, B and C Versions)TEMPERATURE ( C)TEMPERATURE ( C)100806040200 20 20 VOLTAGE LOCK OUT LEVEL (V)SUPPLY VOLTAGE HYSTERESIS LEVEL (V)120 VCC(on)VCC(off)120 Figure 5. Supply Voltage VCC(ON) Threshold Temperature (D Version)Figure 6. Supply Voltage Hysteresis Temperature (D Version)TEMPERATURE ( C)TEMPERATURE ( C)100806040200 20 20 VOLTAGE LOCK OUT LEVEL (V)SUPPLY VOLTAGE HYSTERESIS LEVEL (V)120120 Figure 7.

9 Start up Current (ICC1) vs. JunctionTemperatureFigure 8. Supply Current (ICC3) vs. JunctionTemperatureTEMPERATURE ( C)TEMPERATURE ( C)100806040200 20 4001020304050100806040200 20 40012345 STARTUP Current ICC1 (mA)SUPPLY Current ICC3 (mA) CHARACTERISTICSF igure 9. Supply Current (ICC3) vs. SupplyVoltageFigure 10. Current Sense Voltage Thresholdvs. Junction TemperatureSUPPLY VOLTAGE Vcc (V)TEMPERATURE ( C)302520151001234120806040200 20 11. Leading Edge Blanking Time TemperatureFigure 12. Leading Edge Blanking Time VoltageTEMPERATURE ( C)SUPPLY VOLTAGE Vcc (V)100806040200 20 4005010015020025030030252015100501001502 00250300 SUPPLY Current ICC3 (mA) Current SENSE VOLTAGETHRESHOLD (V)LEADING EDGE BLANKING TIME (ns)LEADING EDGE BLANKING TIME (ns) 13.

10 Propagation Delay from CS to DRVvs. Junction TemperatureFigure 14. Propagation Delay from CS to DRVvs. Supply VoltageTEMPERATURE ( C)SUPPLY VOLTAGE Vcc (V)1201008060200 20 4002040608010014016030252015100204060801 20140160 PROPAGATION DELAY (ns)PROPAGATION DELAY (ns) CHARACTERISTICSF igure 15. Oscillator Frequency vs. JunctionTemperatureFigure 16. Oscillator Frequency vs. SupplyVoltageTEMPERATURE ( C)SUPPLY VOLTAGE Vcc (V)120806040200 20 4092949698100104106108302520151092949698 100104106108 Figure 17. Oscillator Frequency vs. OscillatorResistorRt RESISTOR (kW)TEMPERATURE ( C)10080604020005015020030035040050010080 6040200 20 4045464849 OSCILLATOR FREQUENCY @ Rt = 43 kW (kHz)SWITCHING FREQUENCY, FSW (kHz)MAXIMUM DUTY CYCLE (%)102100102 OSCILLATOR FREQUENCY @ Rt = 43 kW (kHz)10025045047120 Figure 18.