最近做一款NCP1200的电源,输出3
创维通病及疑难故障解决方法
创维通病及疑难故障解决方法电视机安装遥控器，它的场脉冲取出的脚就是场输出电路的输出脚（接场偏转的脚），因此按电视机安装遥控器的方法应急处理，也在AN5521的2脚取出场脉冲。
但需要适当改动一下就可12,机型：29T95HT,(6T18),故障：行、场不同步，无AV ：检修过程：对照电路图，查行电路上元件未见异常，无奈！代换数字板也无效。
再仔细检查TB1261及其外围，发现其34#电压异常。
在此脚外围有1个电容--C028（820P），查之漏电，换掉它，一切OK。
C028（820P）图纸上没有标着，希望大家以后注意！13,机型：29T96HS,(6M31),故障：图象左右晃动检修过程：因为以前见过6D81机芯出现过类似故障，故检查数字板上的行定时电容，结果发现，CM84（）电容不良。
换之，故障排除。
14,机型：34SIHT,（6D96）故障：吱吱响，不开机：检修过程：通电后，吱吱响，不开机。
测+B电容两端直流电阻，正反向都是560欧，断开行包+B供电脚，+B电容两端直流电阻恢复正常，怀疑行包不良。
代换后，故障依旧。
仔细检查发现，视放供电+200V存在短路，换视放块IC801（LM2429TE）后不再吱吱响；但是灯亮，不开机，+B电压不稳定，在110V—140V间抖动。
查行电路没有工作。
换掉IC501（LM1269）故障彻底排除。
15,机型：34SIHT,（6D96）故障：枕形失真。
检修过程：检查枕校电路所有元件，未见异常。
枕校管Q708的C极电压为0V，无奈！用代换法换掉所怀疑的所有元件，也没有解决。
随怀疑数字板上输出的EW 信号异常，换数字板，涛声依旧！没有办法只能怀疑断板，仔细测量枕校电路所有走线，发现，Q705（A1015）、Q706（A1015）的e极之间的走线不通，但外观没有断裂痕迹，连接之，故障排除。
16，机型：29T83HT/6T18故障现象；接受TV信号时不定时图象闪动，严重时无信号。
NCP1200 NCP1200A中文资料
控制芯片的自身供电往往是最关键的部分袁 关系到芯片自身的功耗和输出输入电压变化时芯 片工作的稳定性遥 另外袁峰值电流控制模式袁在输 出功率变化较大时袁电流峰值脉动较大袁产生很强 的音频噪声袁 而在低输出功率的条件下电路的效 率很低遥
NCP1200A 的动态自供电和跳周期功能成功 地解决了上述问题遥
中图分类号院TN492 文献标识码院A 文章编号院0219-2713渊2006冤05-0021-04
0 引言
反激电源由于拓扑简单袁输入输出电气隔离袁 升降压范围广袁成本低袁在小功率的辅助电源尧适 配器等场合得到广泛的应用遥
传统的单端反激电源采用经典芯片 UC3842 控制遥 但是 UC3842 需要辅助供电绕组尧外围电路 复杂尧所需器件多尧体积大并且成本高遥 安森美公 司推出的采用甚高电压集成电路渊VHVIC冤技术的 NCP1200 系列低功耗峰值电流控制芯片袁 将多种 功能集成于芯片内部袁 可以作为通用的离线式开 关电源的控制器遥 与 NCP1200 相比袁NCP1200A 提 高了输出驱动能力袁 用该芯片控制的反激电源具 有优越的性能遥
渊2冤 反馈电路 输出通过 TL431 直接反馈袁 使输出电压有较低的纹波系数及较理想的负荷调 整率曰
渊3冤电流采样输入的低通滤波器R5尧C3 实验 中发现功率管开通时产生的高频电流尖峰持续时 间很短袁完全可以被内部前沿消隐电路屏蔽袁不会 导致输出脉冲的误关断袁所以 R5尧C3 可以不接曰
渊4冤 电阻R3尧R4 芯片内部有驱动输出拉/灌 渊40/10 赘冤电阻袁R4 增加驱动电路电阻袁降低开通 时开关管的 dv/dt曰 R3 可以加快功率管的关断袁但 增加管子的 di/dt袁EMI 较大遥 调试的样机功率较 小袁省去这两个电阻袁电路工作良好遥
PR-NCP1200
Ground
T1
SMD + C1 4.7µF/350V + C2 4.7µF/350V
NCP1200
1 Fosc = 35kHz HV 8 Adj 2
FB
7
Universal Input 通用输入
3 4
CS 1 Vcc 6 Gnd Drv 5
M1 MTD1N60E
470pF/1kV C4 thru holes
Q1 2N3904 68 R7 C5 2.2nF Y type R9 2.2 100 R8
SMD
Christophe BASSO 12
安森美半导体
安森美半导体的开关电源方案 安森美半导体的开关电源方案
3.5W壁式变换器应用电路
330µH L1 D2 MBRA140LT3 L2 4.7µH 6V@600mA + 470µF/10V C6 + 10µF/10V C7
Clock
S Q Q R
至驱动器
V漏极 100V/格, X = 500µs / 格
1/4 FB CS
GAIN
Adj
+
1.2V
+
LEB
-
V漏极 100V/格, X = 5µs / 格
-
跳转电平可调
Christophe BASSO 7
安森美半导体
安森美半导体的开关电源方案 安森美半导体的开关电源方案
待机状态NCP1200运行无噪声 NCP1200
D3 MMSZ5V1
10 R1 1W + 1W SMD R4 2.7 IC1 SFH6156-2 R6 470
10µF/16V C3
C5 2.2nF Y type
NCP1200A中文资料
NCP1200APWM Current−Mode Controller for UniversalOff−Line Supplies Featuring Low Standby PowerHoused in SOIC−8 or PDIP−8 package, the NCP1200A enhances the previous NCP1200 series by offering a reduced optocoupler current together with an increased drive capability. Due to its novel concept, the circuit allows the implementation of complete off−line AC−DC adapters, battery charger or a SMPS where standby power is a key parameter.With an internal structure operating at a fixed 40 kHz, 60 kHz or 100kHz, the controller supplies itself from the high−voltage rail, avoiding the need of an auxiliary winding. This feature naturally eases the designer task in battery charger applications. Finally, current−mode control provides an excellent audio−susceptibility and inherent pulse−by−pulse control.When the current setpoint falls below a given value, e.g. the output power demand diminishes, the IC automatically enters the so−calledskip cycle mode and provides excellent efficiency at light loads. Because this occurs at a user adjustable low peak current, no acoustic noise takes place.The NCP1200A features an efficient protective circuitry which, in presence of an overcurrent condition, disables the output pulses while the device enters a safe burst mode, trying to restart. Once the default has gone, the device auto−recovers.Features•Pb−Free Packages are Available•No Auxiliary Winding Operation•Auto−Recovery Internal Output Short−Circuit Protection •Extremely Low No−Load Standby Power•Current−Mode Control with Skip−Cycle Capability •Internal Temperature Shutdown•Internal Leading Edge Blanking•250 mA Peak Current Capability•Internally Fixed Frequency at 40 kHz, 60 kHz and 100 kHz •Direct Optocoupler Connection•SPICE Models Available for TRANsient and AC Analysis •Pin to Pin Compatible with NCP1200Typical Applications•AC−DC Adapters for Portable Devices•Offline Battery Chargers•Auxiliary Power Supplies (USB, Appliances, TVs, etc.)SOIC−8D SUFFIXCASE 75118MARKINGDIAGRAMSPIN CONNECTIONSPDIP−8P SUFFIXCASE 6268181200APxxxAWLYYWW200AyALYWxxx=Specific Device Code(40, 60 or 100)y=Specific Device Code(4 for 40, 6 for 60, 1 for 100)A=Assembly LocationWL, L=Wafer LotY, YY=YearW, WW=Work Week1Adj8HV2FB3CS4GND7NC6V CC5Drv(Top View)MINIATURE PWMCONTROLLER FOR HIGHPOWER AC−DC WALLADAPTERS AND OFFLINEBATTERY CHARGERSSee detailed ordering and shipping information in the package dimensions section on page 13 of this data sheet.ORDERING INFORMATIONFigure 1. Typical Application ExampleV OUT*Please refer to the application information sectionPIN FUNCTION DESCRIPTIONFigure 2. Internal Circuit ArchitectureMAXIMUM RATINGSvalues (not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied, damage may occur and reliability may be affected.ELECTRICAL CHARACTERISTICS (For typical values T J = 25°C, for min/max values T J = 0°C to +125°C, Max T J = 150°C,Internal Oscillator (V = 11 V, pin 5 loaded by 1.0 k W)1.Max value at T J= 0°C.2.Maximum value @ T J = 25°C, please see characterization curves.3.Pin 5 loaded by 1.0 nF.60065070075080085090001020304050607011.111.311.511.711.912.112.312.5−252550751001253844505662687480869298104110−25255075100125L E A K A G E (m A )TEMPERATURE (°C)V C C (o f f ), T H R E S H O L D (V )Figure 4. V CC(off) vs. TemperatureV C C (o n ), (V )I C C 1 (m A )TEMPERATURE (°C)I C C 2 (m A )Figure 7. ICC2 vs. TemperatureTEMPERATURE (°C)F S W (k H z )Figure 8. Switching Frequency vs. Temperature1.001.051.101.151.201.251.301.351.40−25255075100125−25255075100125TEMPERATURE (°C)I C C 3 (m A)190220250280310340370400430460490Figure 9. V CC Latchoff vs. TemperatureFigure 10. ICC3 vs. TemperatureFigure 11. Drive and Source Resistance vs.TemperatureTEMPERATURE (°C)C U R R E N T S E T P O I N T (V )Figure 12. Current Sense Limit vs. TemperatureTEMPERATURE (°C)V S K I P (V )Figure 13. V SKIP vs. TemperatureFigure 14. Max Duty Cycle vs. TemperatureTEMPERATURE (°C)V C C L A T C H O FF5.155.205.255.305.355.405.455.50−25255075100125TEMPERATURE (°C)D U T Y M A X (%)−250255075100125TEMPERATURE (°C)O h m01020304050600.800.840.880.920.961.00−2502550751001257375777981838587−25025*******125APPLICATION INFORMATIONIntroductionThe NCP1200A implements a standard current mode architecture where the switch−off time is dictated by the peak current setpoint. This component represents the ideal candidate where low part−count is the key parameter,particularly in low−cost AC−DC adapters, auxiliary supplies, etc. Due to its high−performance High−V oltage technology, the NCP1200A incorporates all the necessary components normally needed in UC384X based supplies:timing components, feedback devices, low−pass filter and self−supply . This later point emphasizes the fact that ON Semiconductor’s NCP1200A does NOT need an auxiliary winding to operate: the product is naturally supplied from the high−voltage rail and delivers a V CC to the IC. This system is called the Dynamic Self−Supply (DSS).Dynamic Self−SupplyThe DSS principle is based on the charge/discharge of the V CC bulk capacitor from a low level up to a higher level. We can easily describe the current source operation with a bunch of simple logical equations:POWER−ON: IF V CC < VCC H THEN Current Source is ON, no output pulsesIF V CC decreasing > VCC L THEN Current Source is OFF,output is pulsingIF V CC increasing < VCC H THEN Current Source is ON,output is pulsingTypical values are: VCC H = 12 V , VCC L = 10 VTo better understand the operational principle, Figure 15’s sketch offers the necessary light:Figure 15. The charge/discharge cycle over a10 m F V CC capacitorV The DSS behavior actually depends on the internal IC consumption and the MOSFET’s gate charge Qg. If we select a MOSFET like the MTP2N60E, Qg max equals 22nC. With a maximum switching frequency of 68 kHz for the P60 version, the average power necessary to drive the MOSFET (excluding the driver efficiency and neglecting various voltage drops) is:F SW ⋅ Qg ⋅ V CC withF SW = maximum switching frequency Qg = MOSFET’s gate chargeV CC = V GS level applied to the gateTo obtain the final IC current, simply divide this result by V CC : I driver = F SW ⋅ Qg = 1.5 mA. The total standby power consumption at no−load will therefore heavily rely on the internal IC consumption plus the above driving current (altered by the driver’s efficiency). Suppose that the IC is supplied from a 350 VDC line. The current flowing through pin 8 is a direct image of the NCP1200A consumption (neglecting the switching losses of the HV current source).If ICC2 equals 2.3 mA @ T J = 25°C, then the power dissipated (lost) by the IC is simply: 350 x 2.3 m = 805 mW.For design and reliability reasons, it would be interesting to reduce this source of wasted power which increases the die temperature. This can be achieved by using different methods:e a MOSFET with lower gate charge Qg2.Connect pin through a diode (1N4007 typically) to one of the mains input. The average value on pin 8becomes V MAINS(peak)@2p. Our power contribution example drops to: 223 x 2.3 m = 512mW. If a resistor is installed between the mains and the diode, you further force the dissipation to migrate from the package to the resistor. Theresistor value should account for low−line startups.3.Permanently force the V CC level above VCC H with an auxiliary winding. It will automaticallydisconnect the internal startup source and the IC will be fully self−supplied from this winding.Again, the total power drawn from the mains will significantly decrease. Make sure the auxiliary voltage never exceeds the 16 V limit.Figure 16. A simple diode naturally reduces the average voltage on pin 8mainsSkipping Cycle ModeThe NCP1200A automatically skips switching cycles when the output power demand drops below a given level.This is accomplished by monitoring the FB pin. In normal operation, pin 2 imposes a peak current accordingly to the load value. If the load demand decreases, the internal loop asks for less peak current. When this setpoint reaches a determined level, the IC prevents the current from decreasing further down and starts to blank the output pulses: the IC enters the so−called skip cycle mode, also named controlled burst operation. The power transfer now depends upon the width of the pulse bunches (Figure 18).Suppose we have the following component values:Lp, primary inductance = 1 mH F SW , switching frequency = 61 kHz Ip skip = 200 mA (or 333 mV/R SENSE)The theoretical power transfer is therefore:12@Lp @Ip 2@FSW +1.2W If this IC enters skip cycle mode with a bunch length of 20ms over a recurrent period of 100 ms, then the total power transfer is: 1.2 . 0.2 = 240 mW.To better understand how this skip cycle mode takes place,a look at the operation mode versus the FB levelimmediately gives the necessary insight:Figure 17.When FB is above the skip cycle threshold (1 V by default), the peak current cannot exceed 1 V/R SENSE . When the IC enters the skip cycle mode, the peak current cannot go below Vpin1 / 3.3. The user still has the flexibility to alter this 1 V by either shunting pin 1 to ground through a resistor or raising it through a resistor up to the desired level.Grounding pin 1 permanently invalidates the skip cycle operation.Power P1Power P2Power P3Figure 18. Output Pulses at Various Power Levels (X = 5.0 m s/div) P1 t P2 t P3Figure 19. The Skip Cycle Takes Place at Low Peak Currents which Guaranties Noise−FreeOperation315.40882.70 1.450 M 2.017 M 2.585 M300 M200 M100 MWe recommend a pin 1 operation between 400 mV and 1.3V that will fix the skip peak current level between 120 mV / RSENSE and 390 mV / RSENSE.Non−Latching ShutdownIn some cases, it might be desirable to shut off the part temporarily and authorize its restart once the default hasdisappeared. This option can easily be accomplished through a single NPN bipolar transistor wired between FB and ground. By pulling FB below the Adj pin 1 level, the output pulses are disabled as long as FB is pulled below pin 1. As soon as FB is relaxed, the IC resumes its operation.Figure 20 depicts the application example:Figure 20. Another Way of Shutting Down the IC without a Definitive Latchoff StatePower DissipationThe NCP1200A is directly supplied from the DC rail through the internal DSS circuitry. The average current flowing through the DSS is therefore the direct image of the NCP1200A current consumption. The total power dissipation can be evaluated using: (V HVDC − 11 V) ⋅ ICC2. If we operate the device on a 250 V AC rail, the maximum rectified voltage can go up to 350 VDC. However, as the characterization curves show, the current consumption drops at high junction temperature, which quickly occurs due to the DSS operation. At T J = 50°C, ICC2 = 1.7 mA for the 61 kHz version over a 1 nF capacitive load. As a result, the NCP1200A will dissipate 350 . 1.7 mA@T J = 50°C = 595 mW. The SOIC−8 package offers a junction−to−ambient thermal resistance R q JA of 178°C/W. Adding some copper area around the PCB footprint will help decreasing this number: 12 mm x 12 mm to drop R q JA down to 100°C/W with 35 m copper thickness (1 oz.) or 6.5 mm x 6.5 mm with 70 m copper thickness (2 oz.). With this later number, we can compute the maximum power dissipation the package accepts at an ambient of 50°C:Pmax+T Jmax*T AmaxR q JA+750mWwhich is okay withour previous budget. For the DIP8 package, adding a min−pad area of 80 mm@ of 35 m copper (1 oz.), R q JA drops from 100°C/W to about 75°C/W.In the above calculations, ICC2 is based on a 1 nF output capacitor. As seen before, ICC2 will depend on your MOSFET’s Qg: ICC2 ≈ ICC1 + F SW x Qg. Final calculation shall thus accounts for the total gate−charge Qg your MOSFET will exhibit. The same methodology can be applied for the 100 kHz version but care must be taken to keep T J below the 125°C limit with the D100 (SOIC) version and activated DSS in high−line conditions.If the power estimation is beyond the limit, other solutions are possible a) add a series diode with pin 8 (as suggested in the above lines) and connect it to the half rectified wave. As a result, it will drop the average input voltage and lower the dissipation to:350@2p@1.7m+380mW b) put an auxiliary winding to disable the DSS and decrease the power consumption to V CC x ICC2. The auxiliary level should be thus that the rectified auxiliary voltage permanently stays above 10 V (to not re−activate the DSS) and is safely kept below the 16 V maximum rating.Overload OperationIn applications where the output current is purposely not controlled (e.g. wall adapters delivering raw DC level), it is interesting to implement a true short−circuit protection. A short−circuit actually forces the output voltage to be at a low level, preventing a bias current to circulate in the optocoupler LED. As a result, the FB pin level is pulled up to 4.2 V, as internally imposed by the IC. The peak current setpoint goes to the maximum and the supply delivers a rather high power with all the associated effects. Please note that this can also happen in case of feedback loss, e.g. a broken optocoupler. To account for this situation, NCP1200A hosts a dedicated overload detection circuitry. Once activated, this circuitry imposes to deliver pulses in a burst manner with a low duty cycle. The system auto−recovers when the fault condition disappears. During the startup phase, the peak current is pushed to the maximum until the output voltage reaches its target and the feedback loop takes over. This period of time depends on normal output load conditions and the maximum peak current allowed by the system. The time−out used by this IC works with the V CC decoupling capacitor: as soon as the V CC decreases from the UVLO H level (typically 12 V) the device internally watches for an overload current situation. If this condition is still present when the UVLO L level is reached, the controller stops the driving pulses, prevents the self−supply current source to restart and puts all the circuitry in standby, consuming as little as 350 m A typical (ICC3 parameter). As a result, the V CC level slowly discharges toward 0.TIMETIMETIMEV 12 V 10 V 5.4 VFigure 21. If the fault is relaxed during the V CC natural fall down sequence, the IC automatically resumes.If the fault still persists when V CC reached UVLO L , then the controller cuts everything off until recovery.When this level crosses 5.4 V typical, the controller enters a new startup phase by turning the current source on: V CC rises toward 12 V and again delivers output pulses at the UVLO H crossing point. If the fault condition has been removed before UVLO L approaches, then the IC continues its normal operation. Otherwise, a new fault cycle takes place. Figure 21 shows the evolution of the signals in presence of a fault.Calculating the V CC CapacitorAs the above section describes, the fall down sequence depends upon the V CC level: how long does it take for the V CC line to go from 12 V to 10 V? The required time depends on the startup sequence of your system, i.e. when you first apply the power to the IC. The corresponding transient fault duration due to the output capacitor charging must be less than the time needed to discharge from 12 V to 10 V ,otherwise the supply will not properly start. The test consistsin either simulating or measuring in the lab how much time the system takes to reach the regulation at full load. Let’s suppose that this time corresponds to 6 ms. Therefore a V CC fall time of 10 ms could be well appropriated in order to not trigger the overload detection circuitry. If the corresponding IC consumption, including the MOSFET drive, establishes at 1.8 mA for instance, we can calculate the required capacitor using the following formula:D t +D V @C, with D V = 2 V . Then for a wanted D t of 10 ms, C equals 9 m F or 22 m F for a standard value. When an overload condition occurs, the IC blocks its internal circuitry and its consumption drops to 350 m A typical. This happens at V CC = 10 V and it remains stuck until V CC reaches 5.4 V: we are in latchoff phase. Again, using the calculated 22 m F and 350m A current consumption, this latchoff phase lasts:296ms.Protecting the Controller Against Negative SpikesAs with any controller built upon a CMOS technology, it is the designer’s duty to avoid the presence of negative spikes on sensitive pins. Negative signals have the bad habit to forward bias the controller substrate and induce erratic behaviors. Sometimes, the injection can be so strong that internal parasitic SCRs are triggered, engendering irremediable damages to the IC if they are a low impedance path is offered between V CC and GND. If the current sense pin is often the seat of such spurious signals, the high−voltage pin can also be the source of problems in certain circumstances. During the turn−off sequence, e.g.when the user unplugs the power supply, the controller is stillfed by its V CC capacitor and keeps activating the MOSFET ON and OFF with a peak current limited by Rsense.Unfortunately, if the quality coefficient Q of the resonating network formed by Lp and Cbulk is low (e.g. the MOSFET Rdson + Rsense are small), conditions are met to make the circuit resonate and thus negatively bias the controller. Since we are talking about ms pulses, the amount of injected charge (Q = I x t) immediately latches the controller which brutally discharges its V CC capacitor. If this V CC capacitor is of sufficient value, its stored energy damages the controller. Figure 22 depicts a typical negative shot occurring on the HV pin where the brutal V CC dischargetestifies for latchup.Figure 22. A negative spike takes place on the Bulk capacitor at the switch−off sequenceSimple and inexpensive cures exist to prevent from internal parasitic SCR activation. One of them consists in inserting a resistor in series with the high−voltage pin to keep the negative current to the lowest when the bulk becomes negative (Figure 23). Please note that the negative spike is clamped to –2 x Vf due to the diode bridge. Please refer to AND8069/D for power dissipation calculations.Another option (Figure 24) consists in wiring a diode from V CC to the bulk capacitor to force V CC to reach UVLOlow sooner and thus stops the switching activity before the bulk capacitor gets deeply discharged. For security reasons, two diodes can be connected in series.Figure 23. A simple resistor in series avoids anylatchup in the controller CV CCD31N4007CV CCRbulk > 4.7 kFigure 24. or a diode forces V CC to reachUVLOlow soonerSpecifications Brochure, BRD8011/D.D SUFFIX CASE 751−07ISSUE AC*For additional information on our Pb−Free strategy and solderingdetails, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D.SOLDERING FOOTPRINT*NOTES:1.DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982.2.CONTROLLING DIMENSION: MILLIMETER.3.DIMENSION A AND B DO NOT INCLUDE MOLD PROTRUSION.4.MAXIMUM MOLD PROTRUSION 0.15 (0.006)PER SIDE.5.DIMENSION D DOES NOT INCLUDE DAMBAR PROTRUSION. ALLOWABLE DAMBARPROTRUSION SHALL BE 0.127 (0.005) TOTAL IN EXCESS OF THE D DIMENSION AT MAXIMUM MATERIAL CONDITION.6.751−01 THRU 751−06 ARE OBSOLETE. NEW STANDARD IS 751−07.DIM A MIN MAX MIN MAX INCHES4.805.000.1890.197MILLIMETERS B 3.80 4.000.1500.157C 1.35 1.750.0530.069D 0.330.510.0130.020G 1.27 BSC 0.050 BSC H 0.100.250.0040.010J 0.190.250.0070.010K 0.40 1.270.0160.050M 0 8 0 8 N 0.250.500.0100.020S5.806.200.2280.244YM0.25 (0.010)Z SXS____ǒmm inchesǓSCALE 6:1P SUFFIX CASE 626−05ISSUE LNOTES:1.DIMENSION L TO CENTER OF LEAD WHEN FORMED PARALLEL.2.PACKAGE CONTOUR OPTIONAL (ROUND OR SQUARE CORNERS).3.DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982.DIM MIN MAX MIN MAX INCHESMILLIMETERS A 9.4010.160.3700.400B 6.10 6.600.2400.260C 3.94 4.450.1550.175D 0.380.510.0150.020F 1.02 1.780.0400.070G 2.54 BSC 0.100 BSC H 0.76 1.270.0300.050J 0.200.300.0080.012K 2.92 3.430.1150.135L 7.62 BSC 0.300 BSC M −−−10 −−−10 N0.76 1.010.0300.040__The product described herein (NCP1200A), may be covered by the following U.S. patents: 6,271,735, 6,362,067, 6,385,060, 6,429,709, 6,587,357. There may be other patents pending.ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. 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ON NCP1200CH D 控制器 说明书
NCP1200CH/D标志图SO-8D 后缀管壳751DIP-8P 后缀管壳626定购信息（顶视图）定购信息器件封装装运NCP1200P DIP-850件/轨NCP1200D SO-898件/轨产品予告通用离线电源小功率电流模式脉宽调制控制器SO-8或DIP8封装的NCP1200代表了向超小型开关电源方向重大飞跃。
由于其采用新型µSell™方案，用它可以构成一个完全离线的电池充电器或只有少数外部元件的备用开关电源。
此外，由于输出短路保护集成在内可使设计人员用它来构成一个，只带简单反馈电路的、成本极低的壁式交流/直流适配器。
由于其内部结构工作于固定的40kHz 或60kHz ，以及控制器用来驱动像IGBT 或MOSFET 之类的低栅极电荷量的器件，因而只需很小的运行功率。
由于采用电流模式控制，NCP1200极大地简化了具有优异的音频敏感性和固有的逐脉冲控制的，可靠的廉价离线变换器的设计。
当电流设置点降到低于给定值时，例如当输出功率需要量减小时，该集成电路自动地进入所谓跳周期模式，以便在轻负载条件下达到极好的效率。
因为这种情况发生在低峰值电流条件下，所以不会产生听得到的噪声。
最后，该集成电路由直流干线自行供电，因而不需要辅助绕组。
这一特点可以保证，在出现低输出电压或短路时，仍正常运行。
特点：• 无需辅助电源绕组• 内部有输出短路保护电路• 空载待机功耗极低• 电流模式带跳周期功能• 内部有前沿消隐电路• 110mA 峰值拉/灌电流能力• 内部固定频率为40kHz 、 60kHz • 通过光耦合器直接连接典型应用• 交流/直流适配器• 离线电池充电器• 辅助/附属电源NCP1200DR2SO-82500/卷带本文件包含正在研制的产品的信息，安森美半导体有权改变或中止该产品的研制，恕不另行通知。
滤波器通用输入电磁干扰管脚功能描述管脚管脚名称功能描述1Adj 调整跳转峰值电流该管脚用来调整发生跳周期的电平2FB 设置峰值电流设定点将光耦合器接至该脚，根据输出功率需求调节峰值电流设定点3CS 电流检测输入该脚检测初级电流，并通过L.E.B 将检测值送入内部比较器4Gnd 集成电路地5Drv 驱动脉冲驱动器到外部MOSFET 的输出6Vcc 集成电路电源该脚接至典型值为10µF 的外部大容量电容7NC 空脚该不连接的管脚用来保证适当的漏电距离8HV由电源线产生Vcc接至高压干线，该管脚将恒定电流注入Vcc 大容量电容内部电路结构图跳周期比较器HV 电流源内部欠压锁定高和低内部稳压器Q 触发器DCmax=80%复位时钟过载故障持续时间地电流检测最大额定值额定值符号值单位电源电压V CC16V最大功耗P D待定W热阻，结至空气RθJA100°C/W工作环境温度T A-25至+85°C最大结温T Jmax125°C保存温度范围T stg-60至+150°C静电放电能力，人体模型（除Vcc和HV以外的所有管脚） 2.0kV静电放电能力，机器模型200V管脚8（HV）最大电压，管脚6（Vcc）接地450V管脚8（HV）最大电压，管脚6（Vcc）通过10µF电容去耦到地500V电气特性（对典型值T A=25°C，对最小/最大值T A=-特性25°C至+85°C，最大T J=125°C，Vcc=11V，除非另有规定）符号额定值管脚最小值典型值最大值单位动态自供电（V pin8=50V, f OSC=40kHz）自供电VCC ON Vcc增加时电流源断开的电平6待定12待定V VCC OFF Vcc减小时电流源接通的电平6待定10待定V ICC1集成电路内部电流消耗，管脚6无输出负载6400µA ICC2集成电路内部电流消耗，管脚接1nF输出负载6 1.5mA ICC3集成电路内部电流消耗，锁定状态6320µA 内部电流源IC1高压电流源，Vcc=VCC H MAX-100mV8待定 4.0待定mA IC2高压电流源，Vcc=08待定mA 驱动输出T r输出电压上升时间@ CL=1nF，输出信号的10-90%567ns T f揄出电压下降时间@ CL=1nF，输出信号的10-90%528ns R OH拉电阻（驱动=0，V gate=VCC H MAX-1V）536ΩR OL灌电阻（驱动=11V，V gate=1V）511Ω器（管脚5空载）电流比较器I IB输入偏置电流，管脚3的输入电平为1V3-0.50.020.5µA I Limit内部电流最大设定值30.9 1.0 1.1V I Lskip跳周期工作时的默认的内部电流设定值3300mV T DEL从电流检测到栅极关断状态的传输延时3200ns T LEB前沿消隐持续期3250ns 器（Vcc=11V，管脚5接1Ω负载）内部振荡器f OSC振荡器频率，40kHz版324048kHz f OSC振荡器频率，60kHz版486072kHz Dmax最大占空比80%反馈部分（Vcc=11V, 管脚5接1Ω负载）R up内部上拉电阻28.0kΩI ratio管脚3至电流设定点分配比 4.0跳周期产生V skip默认的跳转模式电平1 1.2V 管脚1内部输出阻抗1待定kΩ应用信息引言NCP1200采用标准的电流模式结构，其关断时间取决于峰值电流设定值。
AC.DC控制IC的杰作——NCP1200系列IC介绍
AC/DC控制IC的杰作——NCP1200系列IC介绍今年美国ONSEMI公司新推出的为AC/DC交流适配器设计的电流型准谐振式PWM控制IC，将近年来半导体的高科技及PWM IC的高科技集成在一起创造了最优秀的电源控制器系列，其代表产品为NCP1207。
NCP1207为电流型控制准谐振工作的控制IC。
输出的驱动信号由峰值电流设置点来决定其给出输出驱动信号还是关断。
并由磁复位检测到的工作状态来开启。
它共有7个引脚，每个都决定着IC控制的关键参数。
首先它通过磁复位检测确保电源工作在反激变换式断续导通型边缘，准谐振状态。
这样可以使主功率MOSFET工作于零电压开关的软开关状态，即ZVS状态，使功率MOS无开关损耗。
变压器二次侧若用二极管整流，则二极管无反向恢复损耗。
IC的供电采用动态自供电方式（DSS）。
它将内部集成的高压DMOS的漏极（8pin）直接接高压总线,并组成一个高压恒流源供给接在IC 6pin的电解电容充电，当充电电压达到12V时IC开始工作，并有驱动脉冲输出(5pin)。
而当6pin电压低于10V时输出关断。
对于驱动小功率MOSFET时,电容上的能量基本够用，可不必外接Vcc。
对于驱动功率较大的MOSFET时,需要再接入Vcc的供电绕组补充能量，以维持其在10V以上的电平,保持IC能正常工作。
NCP1207还有很好的极低的空载功耗的维持能力。
它采用的是跳跃周期工作形式。
在输出功率低于给定水平时，NCP1207进入自动跨跃开关周期的工作方式。
这是用监视IC的2pin FB端子电平来实现的。
IC正常工作时，2pin上给一个峰值电流，其值取决于负载。
如果负载减小，峰值电流即变小，当其达到设置点水平时，IC即开始消隐输出脉冲。
此时IC进入跨跃周期工作型。
当输出电压下跌到某一点时，输出再重新进入正常工作。
这就有效地保持了空载损耗很低的优点。
其跨越周期的长短还可以用一颗电阻去调整，以便达到最低空载功耗。
SmartPro LCD 120V 1200VA 700W 线型无中断电源说明书
SmartPro LCD 120V 1200VA 700W Line-Interactive UPS, AVR, 2U Rack/Tower, LCD, USB,DB9 Serial, 8 OutletsMODEL NUMBER:SMART1200LCDProvides reliable 1200VA/700W power protection for your desktop computer, network workstation,audio/video components or media center. Protects against surges, line noise, blackouts and brownouts.DescriptionThe SMART1200LCD SmartPro® LCD 120V 1200VA/700W Line-Interactive Uninterruptible Power Supply provides battery backup and AC power protection against blackouts, brownouts, power surges and line noise that can damage electronics or destroy data. Ideal for backing up your desktop computer or audio/visual components, this line-interactive UPS switches to battery backup mode in milliseconds to keep your connected equipment running long enough to save files and shut down safely with no data loss.Eight NEMA 5-15R outlets protect against surges, as well as provide up to 14.3 minutes of UPS battery support at half load (350W) and 4.0 minutes of support at full load (700W). Automatic voltage regulation (AVR) corrects severe undervoltages as low as 75V and overvoltages as high as 147V without using any battery power. EMI/RFI noise filtering improves your equipment's performance and prevents damage. A 870-joule surge suppression rating protects your equipment from harmful power surges.NEMA 5-15P plug with six-foot (1.8 meters) cord connects to any NEMA 5-15R socket. Large rotatable LCD screen shows real-time input voltage, overload, AVR and battery statuses at a glance. Alarm sounds to indicate power loss or low battery. With free PowerAlert® software (available via free web download),the SMART1200LCD enables safe unattended system shutdown and file saves in case of a prolonged power failure.FeaturesReliable Battery BackupProvides 1200VA/700W high-performance power protection for desktop computers, audio/video components, media centers and other electronicsq Supports 50% load (350W) up to 12 minutes and full load (700W) up to 4 minutes q Audible alarm indicates loss of utility power or low batteryq Battery access door enables hot-swappable, user-replaceable internal batteriesqOptimized Outlets8 NEMA 5-15R outlets provide battery backup and protect against surges or spikes that can harm equipment or dataq HighlightsSupports a half-load (350W) up to 14.3 min. during power outageqSupports a full load (700W) up to 4.0 min. during power outage qHigh 97% efficiency in line power modeqFeatures 8 protected NEMA 5-15R outletsqOffers automatic voltage regulation (AVR)qLCD screen reports real-time UPS and power statusqPackage IncludesSMART1200LCD UPS q USB cable q DB9 serial cable q Telephone cable q Mounting hardware qOwner’s ManualqSpecificationsAutomatic Voltage Regulation (AVR)Corrects undervoltages as low as 75V and overvoltages as high as 147V without drawing battery backup powerq Rotatable LCD Status ScreenLarge LCD screen shows real-time input voltage, overload, AVR and battery statusesq Rotates for easy viewing in both horizontal and vertical installations q Dimmer option controls brightness levelqAC Line, Tel/DSL and Ethernet Surge SuppressionSurge suppression rating of 870 joules protects connected equipment and data from harmful power surgesq Built-in RJ-45 jacks protect single-line tel/DSL or network Ethernet connectionqEMI/RFI Line Noise FilteringRemoves electromagnetic and radio frequency interference that can disrupt or damage your equipment's performanceq USB and DB9 Communication Ports and Free PowerAlert SoftwareHID-compliant USB port integrates with built-in power management and auto-shutdown of Windows and macOSq USB and DB9 serial ports work with PowerAlert software (available for free download at/products/power-alert) to enable safe, unattended system shutdown and file saves during prolonged power failureqDB9 port also supports contact closure messaging for AC Present and AC Fail statusqFlexible Installation OptionsNEMA 5-15P plug with 6-ft. (1.83 m) cord connects to any NEMA 5-15R socketq Adapts to vertical or horizontal installation without special hardware q Includes 2U brackets for rack-mount installationq© 2023 Eaton. All Rights Reserved. Eaton is a registered trademark. All other trademarks are the property of their respective owners.。
NCP1200(中文)
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内处于关断状态。则IC的功耗基值为：400V·4mA·0.16=256mW。如果由于设计原因该基值仍太高的话， 有几种方案可以解决该问题：
1、采用更低门控充电值Qg的MOSFET 2、通过二极管（典型应用1N4007）连接引脚到一个主输入端。引脚8上的平均值变为2*Vmains PEAK/
图 3 HV引脚的漏泄电流与温度的关系
图 4 VCC掉电（OFF）与温度的关系
图 5 VCC上电（ON）与温度的关系
图 6 ICC1与温度的关系
图 7 ICC2与温度的关系
图 8 开关频率与TJ的关系
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ON Semiconductor 公司产品
NCP1200
电流模式 PWM 控制器 用于低功耗通用性离线电源
采用 SO-8 或 DIP-8 封装，NCP1200 是向超压缩开关模式电源的一次重大跃进。由于有了全新的设计 理念，该电路接受完全离线电池充电器或待机 SMPS，并且只需要极少数外部元件。并且，集成的输出短 路保护功能让设计者可以组建一个极低成本、带有相应简单反馈器件的 AC/DC 插接式适配器。
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图 2 内部电路结构
极限参数
参
数
电源电压
热电阻结点到自然通风，PDIP8 型
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最近做一款NCP1200的电源，输出3.5W，考虑到减少待机功耗，设计时HV电压通过一个二极管从AC端直接整流（如图），但是在看DA TASHEET时对图中的220K电阻应有不是很明白，麻烦各位高手分析一下。
DA TASHEET中对这一段描述如下：
关于此电阻的应DA TASHEET中解释意思大概如下（图中划红线）：
由于DSS与AC整流的频率存在不同步，当二极管（采用1N4148）与DSS关断时，为了二极管端的电压平衡，需要在二极管两端并联一个220K的电阻。
不过如果采用1N4937可以省略掉该电阻。
分析了很久对，有几个问题：
1.不明白此二极管并联一个电阻是怎么使二极管电压平衡的。
如果去掉会有什么影响？
2.为什么采用1N4937就不用加电阻了？。