TEA1733T 设计手册AN10868_图文.pdf

AN10868GreenChip TEA1733 series fixed frequency flyback controllerRev. 3.1 — 22 May 2013 Application noteDocument informationInfo ContentKeywords GreenChip, TEA1733, SMPS, flyback, adapter, notebook, LCD monitor.Abstract The TEA1733 is a low cost member of the GreenChip family. It is a fixed-frequency flyback controller intended for power supplies up to 75 W for applications such as notebooks, printers and LCD monitors.AN10868 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.Application note Rev. 3.1 — 22 May 2013 2 of 46Contact informationFor more information, please visit: For sales office addresses, please send an email to: salesaddresses@NXP Semiconductors AN10868GreenChip TEA1733 series fixed frequency flyback controllerRevision historyRev Date Descriptionv.3.1 20130522 updated issueModifications: • Section 3.2.5 “VCC capacitor” has been updated.• Section 3.4.11 “UnderVoltage LockOut (UVLO)” has been updated.v.3 20101124 third issuev.2 20100601 second issuev.1 20091209 first issueAN10868 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.Application note Rev. 3.1 — 22 May 2013 3 of 46NXP Semiconductors AN10868GreenChip TEA1733 series fixed frequency flyback controller1. IntroductionThe TEA1733 is a fixed frequency flyback controller that can be used for Discontinuous Conduction Mode (DCM) as well as Continuous Conduction Mode (CCM).1.1 ScopeThis application note describes the functionality of the TEA1733 series. Fixed-frequency flyback fundamentals and calculation of transformer and other large signal parts are not dealt with in this application note. The TEA1733 demoboard is described in a separate user manual (UM10385).1.2 Features• SMPS controller IC enabling low cost applications• Large input voltage range (12 V to 30 V, 35 V peak allowed for 100 ms)• Very low supply current during start and restart (typically 10 PA)• Low supply current during normal operation (typically 500 PA, no load)• Overpower compensation (high/low line compensation)• Adjustable overpower time-out• Adjustable overpower restart timer• Fixed frequency with frequency jitter to reduce EMI• Frequency reduction with fixed minimum peak current at low power operation to maintain high efficiency at low output power levels• Slope compensation for CCM operation• Low and adjustable OverCurrent Protection (OCP) trip level• Soft start• Two independent general purpose protection inputs combined on a single pin (e.g. for OverTemperature Protection (OTP) and output OverVoltage Protection (OVP))• Internal OTP1.3 ApplicationsThe TEA1733 is intended for applications that require an efficient and cost-effective power supply solution up to 75 W such as:• Notebooks• LCD monitors• PrintersAN10868 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.Application note Rev. 3.1 — 22 May 2013 4 of 46NXP Semiconductors AN10868GreenChip TEA1733 series fixed frequency flyback controller1.4 TEA1733 series type overview[1] The only difference between the latch version and the restart version is how the overpower protection is handled (in the N2 versions this is also how UVLO is handled). Protection triggered by the PROTECT pin (output overvoltage protection, overtemperature protection) or by the internal overtemperature protection always results in latched off-state. Protection triggered by the VINSENSE pin (brownout, input overvoltage protection) always triggers a restart.1.5 Latched versions TEA1733LT, TEA1733MT, TEA1733LT/N2 and TEA1733MT/N2All TEA1733 versions are available in a restart version and a latch version. The only difference between the two versions is how the OverPower Protection (OPP) is handled:• TEA1733T, TEA1733P, TEA1733AT, TEA1733BT: OPP event initiates safe restart• TEA1733LT, TEA1733MT: OPP event sets IC in latched off-state• TEA1733LT/N2, TEA1733MT/N2: OPP or UVLO event sets IC in latched off-state1.6 Higher switching frequency versions TEA1733AT, TEA1733MT(/N2) and TEA1733BTIncreasing the switching frequency has an important advantage:• More output power possible with same inductor core sizeBut it also has disadvantages:• Higher switching losses• The switching frequency 2nd harmonic exceeds the 150 kHz boundary and must comply to the EMI standards for conducted emission. This can be a problem if there is no margin left in the low frequency area.Note that in CCM, the power transferred from input to output does not increase linearly with the switching frequency. If the goal is to convert as much energy as possible with the smallest possible core size, CCM should be avoided.1.7 Application schematicFigure 1 shows a typical TEA1733 application schematic.Table 1. TEA1733 series type overviewThis table only shows the differences between the various TEA1733 versions, all other properties are identical.Property T LT LT/N。