1、1 Roman Stuler & Vaclav Drda -January 2015 Confidential ProprietaryNCP1399 current mode resonant controller Evaluation board with NCP4305 SRRoman Stuler & Vaclav DrdaON SemiconductorEvaluation results of final silicon samples NCP1399 current mode LLC controllerTheboardusesNCP1602PFCcontrollerthatisn
2、otfinalsilicon. An errataregardingtheDRVisavailable.NCP1602 DRV issue occurs during the light load operation when PFCstageoperatesinskipmode.The PFC DRV output voltage is 5 V when this issue appears which2 Roman Stuler & Vaclav Drda January -2015 Confidential ProprietarydrivespowerMOSFETintolinearre
3、gionforashorttime.The board is capable safe operation despite this issue but this shouldtakethisintoaccountwhenreviewingPFCstageoperation.FinalNCP1602sampleswillbeavailablemid-AprilNCP1399 Device Overview Features:BO protection Natural line feed-forwardTrue current mode control for improved transien
4、t responseAutomatic dead-time adjust with max DT clampDedicated startup sequence and digital soft-startLatched or auto-recovery input for OVP/OTP protectionsLatched or auto-recovery output short circuit protectionInherent out of resonance switching protectionOpen feedback loop protection Programmabl
5、e fault timer/counter on overload /faultPFC stage operation control according to load conditions3 Roman Stuler & Vaclav Drda January -2015 Confidential ProprietarySkip mode for improved light load efficiencyOff-mode operation for extremely low no-load consumptionVccoperation up to 20 V600 V HighVolt
6、age Floating Driver1 A/0.5 A Peak Current Sink/Source Drive Capability Internal temperature shutdownDesigned with pin-to-adjacent-pin short testing safety considerationsDesigned with open pin testing safety considerationsHigh Voltage Startup Current Source with Extremely low Leakage CurrentDSS Opera
7、tion in off-mode or fault modesVarious device options available and programmable via USB from GUIEvaluation board specification AC input 100 to 275 Vac50/60 Hz PFC with NCP1602 included DC input 350 to 420 Vdccan also be used when the PFC is OFF in order to evaluate LLC stage separately if needed Ou
8、tput: 12 V, 20A max. Auto-recovery overload and short circuit protections NCP4305 & NTMFS5830 are used for secondary rectification, 4 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietarythe SR controller turns-off automatically during skip mode Skip mode under light load conditions with
9、 PFC stage running in skip mode as well Latched Secondary OVP 13.5 V with NCP431 and opto.Evaluation board schematic 5 Roman Stuler & Vaclav Drda January -2015 Confidential ProprietaryNote: Actual setup used for board assembly and measurements. Other PCB layout options exist. Please, refer to backup
10、 slides for full board schematic and layout.Evaluation Board Photo Top Side6 Roman Stuler & Vaclav Drda January -2015 Confidential ProprietaryLLC stage PFC stage EMI filterDC OutputAC InputEvaluation Board Photo Bottom Side7 Roman Stuler & Vaclav Drda January -2015 Confidential ProprietaryNCP1399 an
11、dLLC stage componentsPFC stage componentsSecondary regulatorand OVPDC OutputSR componentsAC InputEvaluation Results boxshadowdwn Test measurementsboxshadowdwn Demonstration of operation of each IC blockboxshadowdwn Medium and full load efficiency results8 Roman Stuler & Vaclav Drda January -2015 Con
12、fidential Proprietaryboxshadowdwn Light-load efficiency and no-load consumption resultsboxshadowdwn Closed loop gain-phase characteristics the LLC power stage The NCP1399 features a high-voltage startup current source The startup source ramps-up the VCC and enables the PFC stage The PFC stage builds
13、 up the Vbulkand Brown-out OK condition for the controller is detected via Vbulk/PFC FB pinApplication Startup primary ICs powering9 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary The LLC stage is enabled The LLC stage turns-on and provides Voutand Vaux to supply PFC and LLC contr
14、ollersApplication Startup primary ICs powering10 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary-Regulator from discrete components is used to limit VCC for the controllers and still allow operation under no load conditions Application Startup 110 Vacprimary ICs poweringCaption:CH1
15、 NCP1399HBCH2 NCP1399VCCCH3 11 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary-Application startup time: 120 ms 110 Vacinput VbulkCH4 IprimaryApplication Startup 230 Vacprimary ICs poweringCaption:CH1 NCP1399HBCH2 NCP1399VCCCH3 12 Roman Stuler & Vaclav Drda January -2015 Confidenti
16、al ProprietaryVbulkCH4 Iprimary-Application startup time: 60 ms 230 Vacinput Startup Sequence and Soft-Start-The resonant converter startup behavior depends on many factors:-Actual bulk capacitor voltage -Actual resonant capacitor voltage-Actual secondary capacitor voltage -Actual resonant tank comp
17、onents parameters-NCP1399 discharges the resonant capacitor and provides a dedicated startup sequence ensuring no hard switching and fast 13 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietarybalancing of average resonant capacitor voltage to Vbulk/2 level.-Digital soft start is placed
18、 after the resonant capacitor voltage is balanced. The soft-start increment and time can be adjusted internally. The current mode operation is initiated naturally during the soft-start phase.Startup Sequence and Soft-StartCaption:CH1 HBCH4 Iprimary14 Roman Stuler & Vaclav Drda January -2015 Confiden
19、tial Proprietary-The resonant capacitor is always discharged before startup to always ensure the same initial conditionStartup Sequence and Soft-StartCaption:CH1 HBCH2 MlowerCH3 15 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary-Startup sequence is then placed with preselected init
20、ial on-times-This technique ensures fast resonant voltage balancing to Vbulk/2Mupper-HBCH4 IprimaryStartup Sequence and Soft-StartCaption:CH1 HBCH4 Iprimary16 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary-Transition to current mode operation occurs after several pulses-The on-tim
21、e is then defined by the internal FB and CS pin signalsStartup Sequence and Soft-StartCH2 NCP1399 FB pinCH3 Vout17 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary-The smooth Voutramp-up is assured by NCP1399-Voutreaches nominal level in 4.5 ms CH4IprimarySteady-state Operation and
22、Current Mode Control18 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary The NCP1399 uses divided resonant capacitor voltage in order to indirectly sense primary resonant tank voltage The CS pin voltage is internally processed and compared with FB pin voltage to define on-time for gi
23、ven switching period The ON-time is processed digitally with a 10 ns resolution= excellent transient response, DC symmetry, Out of res. switching protectionSteady-state Operation 1 A outputCaption:CH1 HBCH4 Iprimary19 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary-Perfect DC symme
24、try assured by the NCP1399 on-time modulationSteady-state Operation 5 A outputCaption:CH1 HBCH4 Iprimary20 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary-Perfect DC symmetry is assured by the NCP1399 on-time modulationSteady-state Operation 10 A outputCaption:CH1 HBCH4 Iprimary21
25、Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary-Perfect DC symmetry is assured by the NCP1399 on-time modulationSteady-state Operation 20 A outputCaption:CH1 HBCH4 Iprimary22 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary-Perfect DC symmetry is assured by the NCP
26、1399 on-time modulationAutomatic Dead-Time Adjust The automatic DT adjust system uses dV/dtsensors on the Vboot pin and prolongs the DT period between HB drivers as long as the dV/dtstays above a certain threshold Maximum DT period clamp is implemented in the IC so that the drivers are turned ON in
27、case the DT period reaches preselected clamp this happens for instance after 1st low side DRV pulse when there is no energy in the resonant tank yet23 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary The DT clamp activation can activate latched or auto recovery DT_maxfault when reac
28、hed during operation The DT_maxfault counter is available to overcome false triggering of the DT_maxfault system in some applications Fixed DT option is also included in the IC and can be programmedAutomatic Dead-Time AdjustCaption:CH1 HBCH2 MlowerCH3 24 Roman Stuler & Vaclav Drda January -2015 Conf
29、idential Proprietary-There is no current in the tank after 1st Mlower pulse thus the maximum DT clamp (600 ns in this case) is reachedMupper-HBCH4 IprimaryAutomatic Dead-Time AdjustCaption:CH1 HBCH2 MlowerCH3 25 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary-There is already curre
30、nt in the tank after few pulses and DT is adjusted automatically according to the HB pin transitionMupper-HBCH4 IprimaryAutomatic Dead-Time Adjust HB going downCaption:CH1 HBCH2 MlowerCH3 26 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary-Total DT period includes 180 ns delay from
31、ZVS sensor and driverMupper-HBAutomatic Dead-Time Adjust HB going upCaption:CH1 HBCH2 MlowerCH3 27 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary-Total DT period includes 180 ns delay from ZVS sensor and driverMupper-HBOver Temperature/Voltage Protection The OTP/OVP pin allow for
32、simple IC implementation in adapters, chargers, or other applications28 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary The OTP/OVP fault can be latched or auto-recovery with a preselected auto-recovery timeOver Temperature/Voltage Protection29 Roman Stuler & Vaclav Drda January -2
33、015 Confidential Proprietary Secondary OVP is implemented in the demo-board IC latches OFF when OVP occurs in this version of demo-board Board needs to be disconnected from mains to allow restartOver Temperature/Voltage ProtectionCaption:CH2 OVP/OTPCH3 VoutCH4 30 Roman Stuler & Vaclav Drda January -2015 Confidential Proprietary-The OVP/OTP pin is pulled up by opto when Vout is above 13.5 VIprimary
