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1. 目的 /Objective
元件使用率的测试是检查元件在不同的测试条件下﹐实际使用电压﹑电流和功率跟其额定值的比值﹐这是确保产品没有由于元件超出使用范围而引起损坏。
Component derating test is to check the ratio of actual voltage, current and power applied to a component against their rated value under various test conditions. This is to ensure that no component is overstressed which may cause failure of the product.
2. 范围 /Scope
适用于柏怡电子厂开发的所有产品。
Applicable to all products developed by PI Electronics.
3. 使用仪器 /Main equipment
在工程样板1(EVT)和工程样板2(DVT)阶段﹐所有元件均必须测试。 数字存储示波器 /Storage oscilloscope 数字万用表 /DVM 电子负载 /Electronic load 有效值数字表 /RMS meter 电流探头 /Current probe
4. 步骤 /Procedure
在工程样板1(EVT)和工程样板2(DVT)阶段﹐所有元件均必须测试。 All components shall be tested once in EVT stage, once in DVT stage.
4.1 使用率测试覆盖范围 /Test coverage
在工程样板2(DVT)阶段后﹐如有任何元件改变﹐则只重检由于改变而影响的元件。 If there is any component change after DVT, recheck components affected by the change.
4.2 测试条件 /Test condition
除非有特别规定﹐否则使用下列定义﹕
Unless otherwise specifed, following definition were used.
最大输入电压﹕2Vac(对于仅用110V供电的产品则用135Vac) Max Vin : 2Vac (or 135Vac for 110Vac only system)
最小输入电压﹕90Vac (对于仅用220V供电的产品则用180Vac) Min Vin : 90Vac (or 180Vac for 220Vac only system) 最大输出负载﹕最大的连续负载 Max load : maximum continuous load. 最小输出负载﹕最小的连续负载
Min load : minimum continuous load.
除非有特别规定﹐正常工作条件的使用率测试必须在室温下对所有元件并按下列三种条件进行测试﹕
Unless otherwise specified, nominal condition derating test shall be done for all components at room temperature under following 3 conditions.
最大输入电压﹐最大输出负载 /Max Vin, max load. 最大输入电压﹐最小输出负载 /Max Vin, min load. 最小输入电压﹐最大输出负载 /Min Vin, max load.
除非有特别规定﹐浪涌/瞬态使用率必须对关键性元件﹐例如﹕开关管﹐输出整流管。在高温及低温下按下列条件进行测试﹕
Unless otherwise specified, surge/transient derating shall be done for critical components, e.g. switching FET, output rectifiers at both low and high temperature under following conditions:
最大输入电压﹐最大输出负载﹐起机 /. Max Vin, max load, start up 最小输入电压﹐最大输出负载﹐关机 /. Min Vin, max load, shutdown 最大输入电压﹐最小输出负载﹐起机 /. Max Vin, min load, start up 最小输入电压﹐最小输出负载﹐关机 /. Min Vin, min load, shutdown
最大输入电压﹐最小输出负载﹐输出短路 /. Max Vin, min load, output short circuit 最大输入电压﹐输出短路然后起机 /. Max Vin, output short circuit, then start up 对于NJRC的产品﹐参阅NJRC的使用率表。 For NJRC product, refer to NJRC derating table.
对于其它的产品﹐参阅柏怡电子厂内部使用率表或客户提供的使用率表。 For other products, refer to PI internal derating table or the derating table provided by customer.
4.3 使用率的要求 /Derating requirement
4.4 测试方法 /Test method
由于在输入大电容上100赫兹的纹波电压﹐用示波器测量时峰值电压或电流会有跳动﹐因此示波器的触发模式应设定为 “正常”﹐然后调节触发电平去找出最大的峰值电压或电流。 Due to 100Hz ripple voltage in bulk capacitor, the peak voltage or current measurement with oscilloscope will also vary at 100Hz. So the trigger mode of oscilloscope shall be set to 'Normal', then adjust the trigger level to find the maximum peak voltage or current. A. 静态条件 /Static condition
必须记录关键性元件的电压和电流波形﹕例如开关管﹐输出整流管。
Voltage and current waveform shall be captured for critical components: e.g. switching FET, output rectifiers.
B. 瞬态条件 /Transient condition
每个测试必须记录两个波形。使用单一模式获得。一个波形用慢速的Hor/Div设置以便整个变化能观察到。一个波形用快速的Hor/Div设置显示2~3个周期﹐调节触发点来得到电压或电流的峰值。两者的波形的峰值必须能对应。
Two waveforms shall be captured for each test. Use single mode acquisition. One waveform with a slow Hor/Div setting so that the whole transition can be seen. One waveform with a fast Hor/Div setting to display 2 or 3 period, adjust the trigger position to find the peak voltage or current waveform. The peak in both waveform shall be correspond. 从这些波形﹐可以得到电压或电流的峰值和计算使用率。
From the waveform, find the peak voltage or current and calculate the derating. 4.4.1 电阻 /Resistor A. 功率 /Power
用RMS 表测量电阻两端的电压﹐根据P=U2/R计算出使用功率﹐有效值表的低端必须连
接到电阻稳定且没有电压跳动的一端。
Measure RMS voltage across resistor, calculate power with the formula P=U^2/R. Lo terminal of RMS meter shall be connected to the resistor end with no voltage swing.
如果电阻两端的电压都有跳动﹐则 If both end of the resistor is swinging, then.
- 如果只有交流电流过电阻﹐用一个交流电流探头和有效值表测量流过电阻的电流。用公式P=I^2*R计算功率。这个方法适用于如, 缓冲电阻﹐MOSFET栅极的驱动电阻。 If only AC flow through the resistor, measure the current flowing through the resistor with an AC current probe and RMS meter. Calculate power with the formula P=I^2*R. This method applies to e.g. snubber resistors, resistors driving MOSFET gate.
- 如果流过电阻的电流有直流成份﹐但是峰值因数很高(为5或者更大)﹐而且电阻的降额使用率有许多余量(为20%或更小)。则用电流探头和有效值表测量流过电阻的电流。功率可以近似的使用公式P=I^2*R来计算。
If current flowing through the resistor got DC component but the crest factor is very high (5 or above), and the derating of the resistor got much margin (20% or less). Then measure the current flowing through the resistor with an AC current probe and RMS meter. Power can be approximated with the formula P=I^2*R.
- 如果流过电阻的电流有直流成份﹐并且峰值因素较低。使用两个探头﹐CH1连接电阻的一端﹐CH2连接电阻的另一端﹐连接一个与电阻电压接近并且没有电压跳动的点作为公共接地点。使用示波器上的MATH功能(CH1-CH2)﹐用示波器预设的功能测量CH1-CH2的RMS值。用公式P=V^2/R计算功率。
If current flowing through the resistor got DC component and crest factor is low. Use 2 probe, CH1 connect to 1 end of resistor, CH2 connect to other end of resistor, GND to a node with no voltage swing and voltage level nearest to that of resistor. Use the MATH
function (CH1-CH2) on oscilloscope, measure the rms value of of CH1-CH2 with the build in function of the oscilloscope. Then calculate power with the formula P=V^2/R
- 以上任何一种情况都可以用直流电流探头。用公式P=I^2*R计算功率。如果电流很小﹐可先把电流通过100圈线圈﹐再测量100圈之总电流﹐这样电流可被放大一百倍。 DC current probe may also be used to measure current through resistor in any case above. Power P=I^2*R. If the current is very small, pass the current through a 100T coil, then measure the total current of the 100T coil, thus the current can be magnified 100 times.
B. 电压 /Voltage
使用示波器测量电阻两端的峰值电压﹐探头的地必须连接到电阻稳定且没有电压跳动的一端。
Use oscilloscope to measure the peak voltage across the resistor, GND of scope probe shall be connected to resistor end with no voltage swing.
如果电阻两未端均有电压跳动﹐用两探头进行测量﹐CH1连到电阻一未端﹐CH2连接到电阻的另一未端﹐探头的地连到一稳定的且电压水平跟电阻电压水平差别较小的一点﹐利用示波器上的MATH(CH1-CH2)﹐CH1-CH2 峰值即为该电阻的峰值电压。
If both end of resistor got voltage swing, use 2 probe, CH1 connect to 1 end of resistor, CH2 connect to other end of resistor, GND to a node with no voltage swing and voltage level nearest to that of resistor. Use the MATH function (CH1-CH2) on oscilloscope, the peak value of CH1-CH2 will be the peak voltage across the resistor.
仅需要测试下列一些电阻的电压使用率。 Need to check voltage derating of some resistors only. - 启机电阻 /Start up resistor.
- 箝位用的放电电阻 /Discharge resistor for clamp. - 缓冲电阻 /Snubber resistor.
4.4.2 电解电容 /Electrolytic capacitor A. 电压 /Voltage
用电压探头去测量电容两端的峰值电压。
Use voltage probe to measure peak voltage across capacitor. B. 纹波电流 /Ripple current
对频率在1KHZ以上的﹐把电容的一脚从电路板上断开﹐串入一小段导线﹐用电流探头
卡在此导线上﹐用有效值表测出输出的纹波电流。
For frequencies above 1KHz, insert a current probe between one capacitor pin and circuit, measure current probe output with rms meter.
对频率在1KHZ以下的﹐把电容的一脚从电路板上断开﹐串入一个电流检测电阻(<0.1Ω的无电感电阻),用有效值表测出检测电阻两端的有效值电压﹐再根据 I=U/R ﹐即可得到纹波电流。
For frequencies below 1KHz, insert a current sense resistor (< 0.1 ohm non inductive resistor) between capacitor and circuit, measure rms voltage across sense resistor. Calculate the ripple current with I=U/R.
对于输入大容量的电容﹐有低频(100HZ)和高频(开关频率﹐如100KHZ)两种电流流过﹐电流的测量必须串一个电流检测电阻去获得﹐而且低频纹波电流和高频纹波电流应分别测量。
For bulk capacitor, both low frequency (100Hz) and high frequency (switching frequency, say 100KHz) current are flowing. The current shall be measured with a current sense resistor. As the low and high frequency ripple shall be measured separately.
在检测电阻上并接一个RC(1k5﹑0.1uF)电路﹐(如下图所示)用有效值表测此0.1uF两端的有效值电压﹐即可得低频纹波电流值﹐此时高频成份已被滤除。
Add an RC (1K5, 0.1uF) across the sense resistor, measure rms voltage across 0.1uF, this will filter out the high frequency, leaving the 100Hz ripple current.
在检测电阻上并接一个RC(0.1u F ﹑1K5)电路(如下图所示)﹐用有效值表测1K5电阻两端的有效值电压﹐根据 I=U/R即可获得高频纹波电流值﹐此时低频成份已被滤除。 Add a CR (0.1uF, 1K5) across the sense resistor, measure rms voltage across 1K5, this will filter out the low frequency, leaving the switching frequency ripple current. Calculate with I=U/R. (Note : R is 0.1 ohm, not 1K5).
当检查两个并连使用的电容的纹波电压时﹐由于接入的测量设备阻抗的影响﹐大部分纹波电流只流经另外一个电容而不流过被测量的这个电容﹐因而测量出的纹波电流值将小于实际值﹐解决的方法是同时在两个电容上都加上测量设备(电流探头或0.1Ω的无电感电阻)然后用有效值表检测和测量设备。(如下图所示)
When checking ripple current of 2 capacitors in parallel, because of the insertion impedance of the measuring device, most ripple current will flow in the other capacitor not under
measurement, the measured ripple current is smaller than actual. Solution is to insert measuring device (current probe or 0.1 ohm non inductive resistor) in each of both capacitor simultaneouly, then measurement each device with RMS meter.
对於直流输入之滤波电解电容﹐如DC-DC换流器﹐DC-AC逆换流器。须使用高交流阻抗之直流电源作输入来测量纹波电流。如此纹波电流才不被分流至直流电源而做成过低之纹波电流读数。
For filtering E-cap used at DC input, e.g. input filter cap of DC-DC converter, DC-AC inverter. The input ripple current shall be measured by supplying the input with a DC source of high AC impedance, so that ripple current will not be diverted to the DC source and cause lower ripple current reading through E-cap.
4.4.3 薄膜电容 / Film capacitor A. 直流电压 / DC Voltage
使用电压探头去测量电容两端的峰值电压。
Use voltage probe to measure peak voltage across capacitor. B. 交流电压 / AC voltage
用一个有效值表去测量电容两端的交流电压。
Measure the AC voltage across the capacitor with an RMS meter. 4.4.4 陶瓷电容 / Ceramic capacitor A. 直流电压 / DC Voltage
用电压探头去测量电容两端的峰值电压。
Use voltage probe to measure peak voltage across capacitor. 4.4.5 晶体三极管和场效应管 /Transistor and FET A. 电压 / Voltage
用电压探头去测量 Vce (或 Vds), Vbe (或 Vgs) 的峰值电压。 Use voltage probe to measure peak Vce (or Vds), Vbe (or Vgs) voltage. B. 电流 / Current
用电流探头去测量 Ice (或 Ids) 的峰值电流。
Use current probe to measure the peak Ice (or Ids) current.
用一个小电阻(0.1Ω或更小的无电感电阻)和一个直流电压表去测量直流平均电流。或用
直流电探头。
Use a small resistor (0.1 ohm or less) and a DC voltmeter to measure the average DC current. Or use DC current probe.
C. 功率 / Power
晶体三极管﹑场效应管的损耗可以分三个部分 The loss in transistor or FET can be divided into 3 parts.
分别用电压和电流探头测量出 Vce (或 Vds) 电压及 Ice (或 Ids) 电流。
Measure Vce (or Vds) voltage and Ic (or Id) current waveform with a voltage and a current
probe respectively.
要准确地测量V1和V2是困难的﹐因为V0和V3高压远远超过示波器上的输入放大器的范围。以下电路或有帮助。
It is difficult to measure V1 and V2 accurately because high voltage of V0 and V3 overload the input amplifier in oscilloscope. The following circuit may help. 电流/电压开关波型 / Current/voltage switching waveform﹕
传导损耗 / Conduction loss = 1/6*(2*V1*I1+2*V2*I2+V1*I2+V2*I1)*Ton/period.
对于场效应管﹐可用Rds(on)计算,但由于Rds受温度影响比较大﹐(在100° C时比25° C时高出70%)﹐因此需要测量在操作条件下场效应管的温度并从供应商提供的数据表中找出相应温度下的Rds(on).
For FET case, Rds(on) may be used for calculation. But Rds(on) varies a lot with temperature. (At 100 deg.C, it is 70% higher than at 25 deg.C). So it is necessary to measure the FET temperature at the operating conditon and find the Rds(on) at that temperature from the data sheet provided by manufacturer.
传导损耗 / Conduction loss =1/3*(I12+I22+I1*I2)*Rds(on)*Ton/Period. 开机损耗 / Turn on loss (假定 / assume V2,V3< 用电压探头去测量二极管两端的峰值电压。 Use voltage probe to measure peak voltage across rectifier. B. 电流 / Current 用一个小电阻(0.1Ω或更小的无电感电阻)﹐或直流电探头去测量直流平均电流及峰值电流。 Use a small resistor (0.1 ohm or less), or DC current probe to measure the average DC current, peak current. 4.4.7 稳压二极管 / Zener Diode A. 电压 /Voltage 用电压探头去测量稳压二极管两端的峰值电压Vrp﹐只需测量反向电压。 Use voltage probe to measure peak voltage Vrp across zener diode, measure reverse peak voltage only. B. 电流 / Current 和稳压管串一个小电阻(0.1Ω或更小的无电感电阻)﹐或钳上一个直流电流探头﹐从示波器上的波型﹐计算平均反向电流 Iravg。(不可以包括正向直流) Insert a small resistor (0.1 ohm or less non inductive) in series with the zener diode, or clamp a DC current probe to it, from the waveform on oscilloscope, calculate the average reverse current Iravg. (The forward current must not be included in the measurement.) C. 功率 / Power 计算功率消耗 / Calculate Power dissipation, P = Vrp*Iravg 4.4.8 反激式功率变压器。/ Flyback power transformer. A. 一般条件 / Nominal condition 检查通过变压器的峰值电流。计算功率变压器的最大磁通密度 。 Check peak current through transformer. Calculate maximum flux density for power transformer Bmax = L * Ipk / (N * Ae) 其中 /Where L = 功率变压器初级绕组的电感 / Inductance of power transformer primary winding N = 初级绕组的圈数 / Number of turns for primary winding Ae = 磁心的有效截面积 / Effective cross section area of ferrite center pole Bmax = 最大磁通密度 / maximum flux density B. 静态过载条件 / Static overload condition 对於此测试﹐开发部须提供一台过流保护被调到规格内最大的一端。 For this test, DE need to supply one unit with OCP adjusted to the maximum end as stated in specification. 在高温﹐最小输入电压条件下﹐增加输出负载以便使输出功率达到最大﹐让设备工作发热。用示波器监测开关管的电流。通过调节触发点来得出Ids的最大值﹐必须没有饱和的迹象。然后计算有关功率变压器的最大磁通密度。 At max temp, min Vin. Increase output load so that output power is maximum. Let the unit run hot. Monitor FET current Ids with a storage scope. find Idsmax by adjusting the trigger position, there shall be no sign of saturation. Calculate maximum flux density for power transformer. 须同时监控功率变压器﹐开关管﹐输出整流管之温度﹐它不能超过元件之温度极限。(对於开关管及整流管﹐无需考虑使用率。对於功率变压器﹐跟异常条件之温度比较。) The temperature of power transformer, FET and output rectifier shall be monitored, it shall not exceed temperature limit of the device (for FET and rectifier, derating is not required, for transformer, compare to the temperature limit under abnormal condition.) C. 瞬态条件 /Transient condition 从整个瞬态条件期间场效应开关管Ids的波形﹐找出Ids的最大值。计算有关功率变压器的最大磁通密度。在评估报告里﹐计算时须列出产生最大Ids(即Bmax)之条件。 From switching FET Ids waveform during transient condition, find Idsmax. Calculate maximum flux density for power transformer. On the evaluation report, list out the conditon where maximum Ids (hence Bmax) occur when performing the calculation. 4.4.9 正激式功率变压器 / Forward converter transformer A. 一般条件 / Nominal condition 检查通过功率变压器之最大VT。计算磁通密度Bmax = V*T/(N*Ae) Check the maximum VT through the power transformer. Calculate flux density Bmax = V*T/(N*Ae) B. 静态过载条件 / Static overload condition 在高温﹐增加输出负载使输出功率为最大。让被测机发热。用一般条件的方法计算最大磁通密度。须在最高及最低输入电压测试。 At maximum temperature, increase output load so that output power is maximum. Let the unit run hot. Calculate maximum flux density in same way as nominal condition. Test at both max and min Vin. C. 瞬态条件 / Transient condition 如果变压器每周期没有完全复位﹐VT便能累积﹐通过VT计算最大磁通密度并不实际。所以须要观察场效应晶体管之电流波型﹐看在高温下开机﹐输出短路﹐输出短路再开机的情况下﹐有没有饱和现象。 Since VT can accumulate if the transformer is not fully resetted every cycle, it is not practical to calculate the maximum flux density from VT. So it is necessary to observe the FET current, see whether there is sign of saturation during power on, output s/c, and s/c then power on at high temp. 正激式功率镇流器 / Forward converter power choke A. 一般条件 / Nominal condition 测试方法跟反激式功率变压器﹐测量电流为通过功率镇流器之电流。 B. 瞬态条件 / Transient condition 功率镇流器之饱和比反激式功率变压器之饱和﹐对场效应晶体管之危险低很多。所以最大 磁通密度祗作为参考。但最坏情况下测出来之效应晶体管电流峰值应少于额定效应晶体管电流峰值的50%才安全。 Saturation of power choke is much less dangerous to the switching FET than saturation of flyback power transformer. So the maximum flux density calculated shall be used as reference only. But the measured peak FET current under worse case shall be less than 50% of the peak FET current rating for the FET to be safe. 铁粉芯镇流器 / Iron power choke 磁通密度计算方法对铁粉芯镇流器无效﹐因为镇流器电感随电流上升而下降。 Flux density calculation method for iron power choke is not valid because the choke inductance drop as current through it increase. 测量通过镇流器之电流。计算NI (圈数 * 电感)﹐另找出磁芯之编号。然后从那磁芯编号之NI 对能量曲线﹐找出储存于磁芯之能量。在同一曲线上﹐找出此磁芯能储存之最大能量。储存之能量应少于磁芯能储存之最大能量。 Measure the current through the power choke. Calculate NI (number of turns * current), and find the p/n of the core. Then use NI vs Energy curve of that particular core p/n, find the energy stored in the core. From the same curve, find the maximum energy that can be handled by the core. The energy stored shall be lower than maximum energy that can be handled by the core. 5. 使用率一览表 /Derating table 5.1 柏怡电子厂内部使用率一览表 / PI internal derating table 浪涌/瞬态工作条件的正常工作条件的使用率 零件类型 参数 使用率比值比值 Component parameter Surge/transient Nominal conditions derating derating 功耗 0.5 1* 电阻 power 电压 resistors 1.0 1 voltage 电压 0.85 0.9 voltage 晶体管 电流 0.9(安全工作区限内) 0.7 bipolar current (SOA limit) transistors 结温 Max Tj-20 ° C Max Tj-10 ° C Tj 电压 0.9#3 1 voltage MOS场效应电流 0.7 0.9* 管 current mosfets 结温 Max Tj-20 ° C Max Tj-10 ° C Tj 电压 0.9 0.9 voltage 整流二极管 电流 0.7 0.9* rectifiers current 结温 Max Tj-20 ° C Max Tj-10 ° C Tj 电压 0.9#1 1 voltage 肖特基二极管 电流 0.8 0.9* schottkies current 结温 Max Tj-20 ° C Max Tj-10 ° C Tj 电压 集成电路 / IC 0.9 1 voltage 二极管电流 0.7 0.9 LED current 光偶 晶体管电压 0.85 0.9 Opto Coupler TR voltage 晶体管电流 0.7 0.9 TR current 电压 voltage 电解电容 Electrolytic capacitors 纹波电流 ripple current 电容寿命 0.9#2 取决于电容寿命及<2.0 Depends on life of cap and <2.0 1.0* 10000Hrs capacitors life DC电压 0.9#4 塑料薄膜电容 DC voltage Plastic film AC 电压 capacitors 1.0 AC voltage 陶瓷电容 电压 0.8 Ceramic voltage capacitors 磁通密度 无饱和 磁性元件 Flux density no saturation 温度 依安规要求 #5 Magnetics temperature According to safety #5. 温度 依IEC950要求(如105°C temperature 规格PCB板温度不超过 塑料/PCB 100°C) Plastic/PCB AC 电压 AC voltage DC 电压 DC voltage 电流 current 1.0 0.8 0.8 0.9* 0.8* 无饱和 no saturation IEC950 limits (below 100 deg.C for 105 deg.C PCB) 连接器 Connectors 注: * 标记的比例基于零件的浪涌/瞬态规格值 * Ratio is based on rated surge/transient limits of the component. #1 VQC部门必须100%检查以及拒收一些漏电电流远大于正常值的元件。但对由于附有很大散热片的而漏电流较大的肖特基二极管可以放宽此要求﹐只要在正常条件下结温是在使用率要求的温度范围之内。 VQC must screen leakage current 100% to ensure devices with leakage currents far away from nominal will be rejected. This condition can be waived only if the schottky is attached to a sufficiently large heatsink so that even for very leaky schottky rectifiers, junction temperature will be kept within temperature derating requirements under nominal conditions. #2 对于276Vac输入﹐400V的电解电容可在桥式整流管之后作电能储存使用。 400V E-cap can be used as bulk storage capacitor after bridge rectification for 276 Vac input. #3 如果测量的峰值电压超过使用率要求 (0.9 * Vdsmax)。使用率还未算不合格。须测量超出使用率范围 (0.9 * Vdsmax) 电压之能量。然后跟场效应管之重复性雪崩能量规格比较﹐如测量之能量须较小﹐使用率可定为合格。 If the measured peak voltage exceed derating (0.9 * Vdsmax). Then the derating is not considered as failed yet. Measure the energy for the portion which voltage exceed 0.9 * Vdsmax. (e.g. for a 600V FET, measure the energy above 0V.) Then compare this energy to the repetitive avalanche energy rating of the FET, if the measured energy is lower, derating is considered as pass. Energy = 1/6*(2*V1*I1 +2*V2*I2 +V1*I2 +V2*I1) *T1 + 1/6*(2*V2*I2 +2*V3*I3 +V2*I3 +V3*I2)*T2 #4 400V之塑料薄膜电容可在桥式整流管之后作滤波使用。 400V polyester film cap can be used as filter capacitor after bridge rectification for 276Vac input. #5 检查须符合那一个安规及变压器的温度等级以决定温度﹐(例如﹐UL1950 class A 最大100 摄氏度, UL1950 class E最大115 摄氏度, UL1950 class B最大120 摄氏度)。如果使用热电偶测量温度﹐必须有十摄氏度余量。如果使用电阻法测量温度﹐则不需要余量。 Check which safety regulation to meet and temperature class of the transformer to decide the temperature limit. (e.g. UL1950 class A 100 deg.C maximum, UL1950 class E 115 deg.C maximum, UL1950 class B 120 deg.C maximum). If temperature is measured with thermocouple, 10 deg.C margin is required. If temperature is measured with resistance method then no margin is required. 5.2 NJRC使用率一览表 /NJRC derating table 5.2.1 元件 /Component 零件类型 Component 正常条件的Derating 比值 Normal conditions derating < 90% Less than 90% 电解电容 Electrolytic Capacitor < 90% Less than 90% 钽电容 < 30% Less than 30% Tantalum Capacitor 薄膜电容 < 80% Less than 80% Film Capacitor 陶瓷电容 < 80% Less than 80% Ceramic Capacitor < 90% 集射结电压Vceo: Less than 90% < 50% 开关晶体管 集电极电流Ic: Less than 50% SW-transistor 结温 < 80% (在室温为 40degC时) Tj: Less than 80% (at Ta=40 deg C) 输出电流 < 70% Less than 70% Io: 二极管 < 80% 浪涌电流Isurge: (快速恢复二极管) Less than 80% < 90% 桥式二极管 重复峰值电压Vrm: Less than 90% Diode Bridge 结温 < 80% (在室温为 40degC时) Tj: Less than 80% (at Ta=40 deg C) 输出电流(平均值) < 70% Less than 70% Io(ave): < 80% 浪涌电流Isurge: 二极管 Less than 80% (肖特基二极管) < 90% 重复峰值电压Vrm: Less than 90% 结温 < 80% (在室温为 40degC室) Tj: Less than 80% (at Ta=40 deg C) < 50% 集电极电流Ic: Less than 50% < 80% 光耦 集射结电压Vceo: Less than 80% Optical isolator < 30% 功率损耗 Less than 30% Pc: 电阻 功率(W) < 50% (PCB温度<100degC) Resistor P(w): Less than 50% (PCB temp < 100 deg C) 参数 Parameter 电压 Voltage : 纹波 Ripple : 电压 Voltage: 电压 Voltage: 电压 Voltage: 5.2.2 温升 /Temperature rise: (输入电压90-110 1: 最大输出负载) 2: ( Input 90-110 Output Max. Load ) 3: 5.2.3 余量﹕/Margin: 平均余量AVR Margin: 绕组﹕最大 60degC /Coil: Max. 60 deg. 外壳﹕最大 30degC /Case: Max. 30 deg. PCB: 45degC /PWB: 45 deg. 最大 80Vac /Max. 80Vac 6. 6.1. 数据的记录 /Data recording 在进行测试以前﹐用电脑作出一份如附录所示Derating test的表格﹐根据元件的多少定 复印的份数。 Before test, print out the derating form as shown in appendix. Duplicate sufficient copies according to the number of components. 6.2. 在进行测试以前﹐首先找出所有元件的使用规格并填入表格中﹐所有元件的填写要分类并按元件号码依次进行如﹕R1﹑R2﹑R3……或C1﹑C2﹑C3…… Before test, find out the component specification and fill into the form. The components shall be classified and filled in order, e.g. R1, R2, R3...., or C1, C2, C3..... 6.3. 6.4. 6.5. 6.6. 6.7. 在做完一个元件的数据测量後﹐要把测量结果及时填入表格中﹐并计算出其使用率。 After testing the data of one component, fill the result into the form, then calculate the derating. 做完一个元件测试的上述步骤後﹐方可进行下一个元件的测试。 After finishing above steps for one component. Proceed to another component. 必须在报告中填写上测试人姓名﹑测试时间﹑样机编号。 Fill in the technicain's name, date, sample number on the form. 不及格的项目必须用红色显示﹐适用于所有元件。 Failed items shall be highlighted in red, apply to all components. 及格并有很大余量的项目必须用蓝色显示﹐适用于较昂贵的元件﹕电解电容﹐场效应管﹐功率整流器。 Items passed with a lot of margin shall be highlighted in blue, apply to more expensive components : E-cap, FET, Power rectifier. 因篇幅问题不能全部显示，请点此查看更多更全内容
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