 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
HT7L5820 Datasheet(PDF) 9 Page - Holtek Semiconductor Inc |
|
|
|||||||||||||||||||||||||||||
HT7L5820 Datasheet(HTML) 9 Page - Holtek Semiconductor Inc |
|
|
9 / 14 page  Rev. 1.20 9 November 17, 2016 HT7L5820/HT7L5821 Temp(°C) Over Temperature Protection Threshold Voltage of RT Pin Functional Description PFC Stage Error Amplifier ThePFCerroramplifierisusedforregulatingthe PFCoutputvoltage.Theerroramplifierinputisthe INVpinanditisconnectedtoaresistordividerfrom thePFCoutput.Theerroramplifierinputvoltageis comparedwithaninternalreferencevoltageof2.5V tomaketheerroramplifiersourceorsinkcurrent tochargeanddischargeitsoutputcapacitor.The capacitorvoltagewilldeterminetheon-timeofthe PFCcontrollertoregulatetheoutputvoltage.The sinkandsourcecapabilityoftheerroramplifieris approximately30uAduringnormaltheoperationand thetypicaltransconductancevalueis150μS. Dynamic Response ThePFCdynamicresponseisveryslowbecauseof thePFCvoltagelooplowfrequencybandwidth.The deviceprovidesanenhanceddynamicresponsefor thePFCloopbydetectingthefeedbackvoltageon theINVpin.WhenevertheINVvoltageislowerthan thereferencevalue2.3V,itwillincreasetheerror amplifiertransconductanceandinturnincreasethe PFCdutycycledirectly.Thischangeindutycycle bypassestheslowchangeoftheCOMPvoltageand thusresultsinafastdynamicresponseforthePFC stage. ZCD Pin Thedeviceperformszerocurrentdetectionbyusing anauxiliarywindingonthePFCboostinductor. Duringnormaloperation,whenthePFCMOSis switchedoff,thestoredenergyinthePFCboost inductorwillreleaseitsenergytotheoutput.The voltageontheZCDpindecreasesasthestoredenergy inthePFCboostinductorisreleasedtotheoutput. WhentheZCDpinvoltageislowerthan0.7V,the internalZCDcomparatoristriggeredandaPFC gatesignalisgenerated.Ifnotriggeringsignalis detectedontheZCDpin,thedevicewillgeneratea restartsignal190μsafterthelastPFCgatesignal.The maximumandminimumvoltageoftheZCDpinis internallyclampedto5.7Vand0Vrespectively SEL Pin Abuilt-inlowvoltageswitchcanbeturnedonoroff accordingtoVINvoltagelevel.Thedrainpinofthis internalswitchisconnectedtotheSELpin. Brown-in/out Protection – VIN Pin Thedevicefeaturesbrown-in/outprotectionusingAC voltagedetection.TheVINpinisusedtodetectthe ACinputvoltageusingaresistordivider.AstheAC voltagedropsandtheVVINvoltagedropsbelow0.9V for100ms,theUVPprotectionfunctionisactivated andtheCOMPpinvoltageisclampedtoaround1.6V. SincealowerCOMPvoltageresultsinareduced PFCon-time,theenergyconcentrationislimitedand thereforethePFCoutputvoltagedecreases.Whenthe INVpinislowerthan1.2V,thedeviceturnsoffall PFCandPWMswitchingoperationsandtheVCCvolt- ageentersthehiccupmode.NotuntiltheVVINvoltage increasesbeyond1.25V(typical)andVCCreachesits turn-onvoltageagainwillthePWMandPFCgate signalsbegenerated. Peak Current Limiting – CSPFC Pin TheCSPFCpinisusedtosensethePFCswitch current.DuringnormalPFCoperation,thevoltage ontheCSPFCpiniscomparedwithathreshold voltage of 0.8V using the internal comparator. WhentheCSPFCpinvoltageisgreaterthanthe thresholdvoltage,thePFCswitchwillbeturnedoff immediately.Thecurrent-senseresistorisadjustable todeterminethePFCswitchpeakcurrent. |
|
|
Link URL |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link to Datasheet | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
